InternPool: remove slice from byte aggregate keys

This deletes a ton of lookups and avoids many UAF bugs.

Closes #19485

lib/std/zig/Zir.zig

@@ -106,12 +106,8 @@ pub const NullTerminatedString = enum(u32) {
 
 /// Given an index into `string_bytes` returns the null-terminated string found there.
 pub fn nullTerminatedString(code: Zir, index: NullTerminatedString) [:0]const u8 {
-    const start = @intFromEnum(index);
+    const slice = code.string_bytes[@intFromEnum(index)..];
-    var end: u32 = start;
+    return slice[0..std.mem.indexOfScalar(u8, slice, 0).? :0];
-    while (code.string_bytes[end] != 0) {
-        end += 1;
-    }
-    return code.string_bytes[start..end :0];
 }
 
 pub fn refSlice(code: Zir, start: usize, len: usize) []Inst.Ref {

src/Compilation.zig

@@ -3159,7 +3159,7 @@ pub fn addModuleErrorMsg(mod: *Module, eb: *ErrorBundle.Wip, module_err_msg: Mod
         const rt_file_path = try module_reference.src_loc.file_scope.fullPath(gpa);
         defer gpa.free(rt_file_path);
         ref_traces.appendAssumeCapacity(.{
-            .decl_name = try eb.addString(ip.stringToSlice(module_reference.decl)),
+            .decl_name = try eb.addString(module_reference.decl.toSlice(ip)),
             .src_loc = try eb.addSourceLocation(.{
                 .src_path = try eb.addString(rt_file_path),
                 .span_start = span.start,
@@ -4074,8 +4074,7 @@ fn workerCheckEmbedFile(
 fn detectEmbedFileUpdate(comp: *Compilation, embed_file: *Module.EmbedFile) !void {
     const mod = comp.module.?;
     const ip = &mod.intern_pool;
-    const sub_file_path = ip.stringToSlice(embed_file.sub_file_path);
+    var file = try embed_file.owner.root.openFile(embed_file.sub_file_path.toSlice(ip), .{});
-    var file = try embed_file.owner.root.openFile(sub_file_path, .{});
     defer file.close();
 
     const stat = try file.stat();
@@ -4444,7 +4443,7 @@ fn reportRetryableEmbedFileError(
     const ip = &mod.intern_pool;
     const err_msg = try Module.ErrorMsg.create(gpa, src_loc, "unable to load '{}{s}': {s}", .{
         embed_file.owner.root,
-        ip.stringToSlice(embed_file.sub_file_path),
+        embed_file.sub_file_path.toSlice(ip),
         @errorName(err),
     });
 

src/InternPool.zig

@@ -351,7 +351,7 @@ const KeyAdapter = struct {
     pub fn eql(ctx: @This(), a: Key, b_void: void, b_map_index: usize) bool {
         _ = b_void;
         if (ctx.intern_pool.items.items(.tag)[b_map_index] == .removed) return false;
-        return ctx.intern_pool.indexToKey(@as(Index, @enumFromInt(b_map_index))).eql(a, ctx.intern_pool);
+        return ctx.intern_pool.indexToKey(@enumFromInt(b_map_index)).eql(a, ctx.intern_pool);
     }
 
     pub fn hash(ctx: @This(), a: Key) u32 {
@@ -385,7 +385,7 @@ pub const RuntimeIndex = enum(u32) {
     _,
 
     pub fn increment(ri: *RuntimeIndex) void {
-        ri.* = @as(RuntimeIndex, @enumFromInt(@intFromEnum(ri.*) + 1));
+        ri.* = @enumFromInt(@intFromEnum(ri.*) + 1);
     }
 };
 
@@ -418,12 +418,44 @@ pub const OptionalNamespaceIndex = enum(u32) {
 
 /// An index into `string_bytes`.
 pub const String = enum(u32) {
+    /// An empty string.
+    empty = 0,
     _,
+
+    pub fn toSlice(string: String, len: u64, ip: *const InternPool) []const u8 {
+        return ip.string_bytes.items[@intFromEnum(string)..][0..@intCast(len)];
+    }
+
+    pub fn at(string: String, index: u64, ip: *const InternPool) u8 {
+        return ip.string_bytes.items[@intCast(@intFromEnum(string) + index)];
+    }
+
+    pub fn toNullTerminatedString(string: String, len: u64, ip: *const InternPool) NullTerminatedString {
+        assert(std.mem.indexOfScalar(u8, string.toSlice(len, ip), 0) == null);
+        assert(string.at(len, ip) == 0);
+        return @enumFromInt(@intFromEnum(string));
+    }
+};
+
+/// An index into `string_bytes` which might be `none`.
+pub const OptionalString = enum(u32) {
+    /// This is distinct from `none` - it is a valid index that represents empty string.
+    empty = 0,
+    none = std.math.maxInt(u32),
+    _,
+
+    pub fn unwrap(string: OptionalString) ?String {
+        return if (string != .none) @enumFromInt(@intFromEnum(string)) else null;
+    }
+
+    pub fn toSlice(string: OptionalString, len: u64, ip: *const InternPool) ?[]const u8 {
+        return (string.unwrap() orelse return null).toSlice(len, ip);
+    }
 };
 
 /// An index into `string_bytes`.
 pub const NullTerminatedString = enum(u32) {
-    /// This is distinct from `none` - it is a valid index that represents empty string.
+    /// An empty string.
     empty = 0,
     _,
 
@@ -447,6 +479,19 @@ pub const NullTerminatedString = enum(u32) {
         return @enumFromInt(@intFromEnum(self));
     }
 
+    pub fn toSlice(string: NullTerminatedString, ip: *const InternPool) [:0]const u8 {
+        const slice = ip.string_bytes.items[@intFromEnum(string)..];
+        return slice[0..std.mem.indexOfScalar(u8, slice, 0).? :0];
+    }
+
+    pub fn length(string: NullTerminatedString, ip: *const InternPool) u32 {
+        return @intCast(string.toSlice(ip).len);
+    }
+
+    pub fn eqlSlice(string: NullTerminatedString, slice: []const u8, ip: *const InternPool) bool {
+        return std.mem.eql(u8, string.toSlice(ip), slice);
+    }
+
     const Adapter = struct {
         strings: []const NullTerminatedString,
 
@@ -467,11 +512,11 @@ pub const NullTerminatedString = enum(u32) {
         return @intFromEnum(a) < @intFromEnum(b);
     }
 
-    pub fn toUnsigned(self: NullTerminatedString, ip: *const InternPool) ?u32 {
+    pub fn toUnsigned(string: NullTerminatedString, ip: *const InternPool) ?u32 {
-        const s = ip.stringToSlice(self);
+        const slice = string.toSlice(ip);
-        if (s.len > 1 and s[0] == '0') return null;
+        if (slice.len > 1 and slice[0] == '0') return null;
-        if (std.mem.indexOfScalar(u8, s, '_')) |_| return null;
+        if (std.mem.indexOfScalar(u8, slice, '_')) |_| return null;
-        return std.fmt.parseUnsigned(u32, s, 10) catch null;
+        return std.fmt.parseUnsigned(u32, slice, 10) catch null;
     }
 
     const FormatData = struct {
@@ -484,11 +529,11 @@ pub const NullTerminatedString = enum(u32) {
         _: std.fmt.FormatOptions,
         writer: anytype,
     ) @TypeOf(writer).Error!void {
-        const s = data.ip.stringToSlice(data.string);
+        const slice = data.string.toSlice(data.ip);
         if (comptime std.mem.eql(u8, specifier, "")) {
-            try writer.writeAll(s);
+            try writer.writeAll(slice);
         } else if (comptime std.mem.eql(u8, specifier, "i")) {
-            try writer.print("{p}", .{std.zig.fmtId(s)});
+            try writer.print("{p}", .{std.zig.fmtId(slice)});
         } else @compileError("invalid format string '" ++ specifier ++ "' for '" ++ @typeName(NullTerminatedString) ++ "'");
     }
 
@@ -504,9 +549,12 @@ pub const OptionalNullTerminatedString = enum(u32) {
     none = std.math.maxInt(u32),
     _,
 
-    pub fn unwrap(oi: OptionalNullTerminatedString) ?NullTerminatedString {
+    pub fn unwrap(string: OptionalNullTerminatedString) ?NullTerminatedString {
-        if (oi == .none) return null;
+        return if (string != .none) @enumFromInt(@intFromEnum(string)) else null;
-        return @enumFromInt(@intFromEnum(oi));
+    }
+
+    pub fn toSlice(string: OptionalNullTerminatedString, ip: *const InternPool) ?[:0]const u8 {
+        return (string.unwrap() orelse return null).toSlice(ip);
     }
 };
 
@@ -690,6 +738,10 @@ pub const Key = union(enum) {
         len: u64,
         child: Index,
         sentinel: Index = .none,
+
+        pub fn lenIncludingSentinel(array_type: ArrayType) u64 {
+            return array_type.len + @intFromBool(array_type.sentinel != .none);
+        }
     };
 
     /// Extern so that hashing can be done via memory reinterpreting.
@@ -1043,7 +1095,7 @@ pub const Key = union(enum) {
         storage: Storage,
 
         pub const Storage = union(enum) {
-            bytes: []const u8,
+            bytes: String,
             elems: []const Index,
             repeated_elem: Index,
 
@@ -1203,7 +1255,7 @@ pub const Key = union(enum) {
 
                 if (child == .u8_type) {
                     switch (aggregate.storage) {
-                        .bytes => |bytes| for (bytes[0..@intCast(len)]) |byte| {
+                        .bytes => |bytes| for (bytes.toSlice(len, ip)) |byte| {
                             std.hash.autoHash(&hasher, KeyTag.int);
                             std.hash.autoHash(&hasher, byte);
                         },
@@ -1240,7 +1292,7 @@ pub const Key = union(enum) {
 
                 switch (aggregate.storage) {
                     .bytes => unreachable,
-                    .elems => |elems| for (elems[0..@as(usize, @intCast(len))]) |elem|
+                    .elems => |elems| for (elems[0..@intCast(len)]) |elem|
                         std.hash.autoHash(&hasher, elem),
                     .repeated_elem => |elem| {
                         var remaining = len;
@@ -1505,11 +1557,11 @@ pub const Key = union(enum) {
                 if (a_info.ty == .c_longdouble_type and a_info.storage != .f80) {
                     // These are strange: we'll sometimes represent them as f128, even if the
                     // underlying type is smaller. f80 is an exception: see float_c_longdouble_f80.
-                    const a_val = switch (a_info.storage) {
+                    const a_val: u128 = switch (a_info.storage) {
-                        inline else => |val| @as(u128, @bitCast(@as(f128, @floatCast(val)))),
+                        inline else => |val| @bitCast(@as(f128, @floatCast(val))),
                     };
-                    const b_val = switch (b_info.storage) {
+                    const b_val: u128 = switch (b_info.storage) {
-                        inline else => |val| @as(u128, @bitCast(@as(f128, @floatCast(val)))),
+                        inline else => |val| @bitCast(@as(f128, @floatCast(val))),
                     };
                     return a_val == b_val;
                 }
@@ -1560,11 +1612,11 @@ pub const Key = union(enum) {
                 const len = ip.aggregateTypeLen(a_info.ty);
                 const StorageTag = @typeInfo(Key.Aggregate.Storage).Union.tag_type.?;
                 if (@as(StorageTag, a_info.storage) != @as(StorageTag, b_info.storage)) {
-                    for (0..@as(usize, @intCast(len))) |elem_index| {
+                    for (0..@intCast(len)) |elem_index| {
                         const a_elem = switch (a_info.storage) {
                             .bytes => |bytes| ip.getIfExists(.{ .int = .{
                                 .ty = .u8_type,
-                                .storage = .{ .u64 = bytes[elem_index] },
+                                .storage = .{ .u64 = bytes.at(elem_index, ip) },
                             } }) orelse return false,
                             .elems => |elems| elems[elem_index],
                             .repeated_elem => |elem| elem,
@@ -1572,7 +1624,7 @@ pub const Key = union(enum) {
                         const b_elem = switch (b_info.storage) {
                             .bytes => |bytes| ip.getIfExists(.{ .int = .{
                                 .ty = .u8_type,
-                                .storage = .{ .u64 = bytes[elem_index] },
+                                .storage = .{ .u64 = bytes.at(elem_index, ip) },
                             } }) orelse return false,
                             .elems => |elems| elems[elem_index],
                             .repeated_elem => |elem| elem,
@@ -1585,18 +1637,15 @@ pub const Key = union(enum) {
                 switch (a_info.storage) {
                     .bytes => |a_bytes| {
                         const b_bytes = b_info.storage.bytes;
-                        return std.mem.eql(
+                        return a_bytes == b_bytes or
-                            u8,
+                            std.mem.eql(u8, a_bytes.toSlice(len, ip), b_bytes.toSlice(len, ip));
-                            a_bytes[0..@as(usize, @intCast(len))],
-                            b_bytes[0..@as(usize, @intCast(len))],
-                        );
                     },
                     .elems => |a_elems| {
                         const b_elems = b_info.storage.elems;
                         return std.mem.eql(
                             Index,
-                            a_elems[0..@as(usize, @intCast(len))],
+                            a_elems[0..@intCast(len)],
-                            b_elems[0..@as(usize, @intCast(len))],
+                            b_elems[0..@intCast(len)],
                         );
                     },
                     .repeated_elem => |a_elem| {
@@ -4175,10 +4224,10 @@ pub const Float64 = struct {
     }
 
     fn pack(val: f64) Float64 {
-        const bits = @as(u64, @bitCast(val));
+        const bits: u64 = @bitCast(val);
         return .{
-            .piece0 = @as(u32, @truncate(bits)),
+            .piece0 = @truncate(bits),
-            .piece1 = @as(u32, @truncate(bits >> 32)),
+            .piece1 = @truncate(bits >> 32),
         };
     }
 };
@@ -4197,11 +4246,11 @@ pub const Float80 = struct {
     }
 
     fn pack(val: f80) Float80 {
-        const bits = @as(u80, @bitCast(val));
+        const bits: u80 = @bitCast(val);
         return .{
-            .piece0 = @as(u32, @truncate(bits)),
+            .piece0 = @truncate(bits),
-            .piece1 = @as(u32, @truncate(bits >> 32)),
+            .piece1 = @truncate(bits >> 32),
-            .piece2 = @as(u16, @truncate(bits >> 64)),
+            .piece2 = @truncate(bits >> 64),
         };
     }
 };
@@ -4222,12 +4271,12 @@ pub const Float128 = struct {
     }
 
     fn pack(val: f128) Float128 {
-        const bits = @as(u128, @bitCast(val));
+        const bits: u128 = @bitCast(val);
         return .{
-            .piece0 = @as(u32, @truncate(bits)),
+            .piece0 = @truncate(bits),
-            .piece1 = @as(u32, @truncate(bits >> 32)),
+            .piece1 = @truncate(bits >> 32),
-            .piece2 = @as(u32, @truncate(bits >> 64)),
+            .piece2 = @truncate(bits >> 64),
-            .piece3 = @as(u32, @truncate(bits >> 96)),
+            .piece3 = @truncate(bits >> 96),
         };
     }
 };
@@ -4244,7 +4293,7 @@ pub fn init(ip: *InternPool, gpa: Allocator) !void {
     assert(ip.items.len == 0);
 
     // Reserve string index 0 for an empty string.
-    assert((try ip.getOrPutString(gpa, "")) == .empty);
+    assert((try ip.getOrPutString(gpa, "", .no_embedded_nulls)) == .empty);
 
     // So that we can use `catch unreachable` below.
     try ip.items.ensureUnusedCapacity(gpa, static_keys.len);
@@ -4329,13 +4378,13 @@ pub fn indexToKey(ip: *const InternPool, index: Index) Key {
         .type_int_signed => .{
             .int_type = .{
                 .signedness = .signed,
-                .bits = @as(u16, @intCast(data)),
+                .bits = @intCast(data),
             },
         },
         .type_int_unsigned => .{
             .int_type = .{
                 .signedness = .unsigned,
-                .bits = @as(u16, @intCast(data)),
+                .bits = @intCast(data),
             },
         },
         .type_array_big => {
@@ -4354,8 +4403,8 @@ pub fn indexToKey(ip: *const InternPool, index: Index) Key {
                 .sentinel = .none,
             } };
         },
-        .simple_type => .{ .simple_type = @as(SimpleType, @enumFromInt(data)) },
+        .simple_type => .{ .simple_type = @enumFromInt(data) },
-        .simple_value => .{ .simple_value = @as(SimpleValue, @enumFromInt(data)) },
+        .simple_value => .{ .simple_value = @enumFromInt(data) },
 
         .type_vector => {
             const vector_info = ip.extraData(Vector, data);
@@ -4506,9 +4555,9 @@ pub fn indexToKey(ip: *const InternPool, index: Index) Key {
         } },
         .type_function => .{ .func_type = ip.extraFuncType(data) },
 
-        .undef => .{ .undef = @as(Index, @enumFromInt(data)) },
+        .undef => .{ .undef = @enumFromInt(data) },
         .opt_null => .{ .opt = .{
-            .ty = @as(Index, @enumFromInt(data)),
+            .ty = @enumFromInt(data),
             .val = .none,
         } },
         .opt_payload => {
@@ -4670,11 +4719,11 @@ pub fn indexToKey(ip: *const InternPool, index: Index) Key {
         },
         .float_f16 => .{ .float = .{
             .ty = .f16_type,
-            .storage = .{ .f16 = @as(f16, @bitCast(@as(u16, @intCast(data)))) },
+            .storage = .{ .f16 = @bitCast(@as(u16, @intCast(data))) },
         } },
         .float_f32 => .{ .float = .{
             .ty = .f32_type,
-            .storage = .{ .f32 = @as(f32, @bitCast(data)) },
+            .storage = .{ .f32 = @bitCast(data) },
         } },
         .float_f64 => .{ .float = .{
             .ty = .f64_type,
@@ -4771,10 +4820,9 @@ pub fn indexToKey(ip: *const InternPool, index: Index) Key {
         },
         .bytes => {
             const extra = ip.extraData(Bytes, data);
-            const len: u32 = @intCast(ip.aggregateTypeLenIncludingSentinel(extra.ty));
             return .{ .aggregate = .{
                 .ty = extra.ty,
-                .storage = .{ .bytes = ip.string_bytes.items[@intFromEnum(extra.bytes)..][0..len] },
+                .storage = .{ .bytes = extra.bytes },
             } };
         },
         .aggregate => {
@@ -4809,14 +4857,14 @@ pub fn indexToKey(ip: *const InternPool, index: Index) Key {
                 .val = .{ .payload = extra.val },
             } };
         },
-        .enum_literal => .{ .enum_literal = @as(NullTerminatedString, @enumFromInt(data)) },
+        .enum_literal => .{ .enum_literal = @enumFromInt(data) },
         .enum_tag => .{ .enum_tag = ip.extraData(Tag.EnumTag, data) },
 
         .memoized_call => {
             const extra = ip.extraDataTrail(MemoizedCall, data);
             return .{ .memoized_call = .{
                 .func = extra.data.func,
-                .arg_values = @as([]const Index, @ptrCast(ip.extra.items[extra.end..][0..extra.data.args_len])),
+                .arg_values = @ptrCast(ip.extra.items[extra.end..][0..extra.data.args_len]),
                 .result = extra.data.result,
             } };
         },
@@ -5596,9 +5644,8 @@ pub fn get(ip: *InternPool, gpa: Allocator, key: Key) Allocator.Error!Index {
             switch (aggregate.storage) {
                 .bytes => |bytes| {
                     assert(child == .u8_type);
-                    if (bytes.len != len) {
+                    if (sentinel != .none) {
-                        assert(bytes.len == len_including_sentinel);
+                        assert(bytes.at(@intCast(len), ip) == ip.indexToKey(sentinel).int.storage.u64);
-                        assert(bytes[@intCast(len)] == ip.indexToKey(sentinel).int.storage.u64);
                     }
                 },
                 .elems => |elems| {
@@ -5641,11 +5688,16 @@ pub fn get(ip: *InternPool, gpa: Allocator, key: Key) Allocator.Error!Index {
             switch (ty_key) {
                 .anon_struct_type => |anon_struct_type| opv: {
                     switch (aggregate.storage) {
-                        .bytes => |bytes| for (anon_struct_type.values.get(ip), bytes) |value, byte| {
+                        .bytes => |bytes| for (anon_struct_type.values.get(ip), bytes.at(0, ip)..) |value, byte| {
-                            if (value != ip.getIfExists(.{ .int = .{
+                            if (value == .none) break :opv;
-                                .ty = .u8_type,
+                            switch (ip.indexToKey(value)) {
-                                .storage = .{ .u64 = byte },
+                                .undef => break :opv,
-                            } })) break :opv;
+                                .int => |int| switch (int.storage) {
+                                    .u64 => |x| if (x != byte) break :opv,
+                                    else => break :opv,
+                                },
+                                else => unreachable,
+                            }
                         },
                         .elems => |elems| if (!std.mem.eql(
                             Index,
@@ -5670,9 +5722,9 @@ pub fn get(ip: *InternPool, gpa: Allocator, key: Key) Allocator.Error!Index {
 
             repeated: {
                 switch (aggregate.storage) {
-                    .bytes => |bytes| for (bytes[1..@as(usize, @intCast(len))]) |byte|
+                    .bytes => |bytes| for (bytes.toSlice(len, ip)[1..]) |byte|
-                        if (byte != bytes[0]) break :repeated,
+                        if (byte != bytes.at(0, ip)) break :repeated,
-                    .elems => |elems| for (elems[1..@as(usize, @intCast(len))]) |elem|
+                    .elems => |elems| for (elems[1..@intCast(len)]) |elem|
                         if (elem != elems[0]) break :repeated,
                     .repeated_elem => {},
                 }
@@ -5681,7 +5733,7 @@ pub fn get(ip: *InternPool, gpa: Allocator, key: Key) Allocator.Error!Index {
                         _ = ip.map.pop();
                         const elem = try ip.get(gpa, .{ .int = .{
                             .ty = .u8_type,
-                            .storage = .{ .u64 = bytes[0] },
+                            .storage = .{ .u64 = bytes.at(0, ip) },
                         } });
                         assert(!(try ip.map.getOrPutAdapted(gpa, key, adapter)).found_existing);
                         try ip.items.ensureUnusedCapacity(gpa, 1);
@@ -5710,7 +5762,7 @@ pub fn get(ip: *InternPool, gpa: Allocator, key: Key) Allocator.Error!Index {
                 try ip.string_bytes.ensureUnusedCapacity(gpa, @intCast(len_including_sentinel + 1));
                 try ip.extra.ensureUnusedCapacity(gpa, @typeInfo(Bytes).Struct.fields.len);
                 switch (aggregate.storage) {
-                    .bytes => |bytes| ip.string_bytes.appendSliceAssumeCapacity(bytes[0..@intCast(len)]),
+                    .bytes => |bytes| ip.string_bytes.appendSliceAssumeCapacity(bytes.toSlice(len, ip)),
                     .elems => |elems| for (elems[0..@intCast(len)]) |elem| switch (ip.indexToKey(elem)) {
                         .undef => {
                             ip.string_bytes.shrinkRetainingCapacity(string_bytes_index);
@@ -5730,15 +5782,14 @@ pub fn get(ip: *InternPool, gpa: Allocator, key: Key) Allocator.Error!Index {
                         else => unreachable,
                     },
                 }
-                const has_internal_null =
-                    std.mem.indexOfScalar(u8, ip.string_bytes.items[string_bytes_index..], 0) != null;
                 if (sentinel != .none) ip.string_bytes.appendAssumeCapacity(
                     @intCast(ip.indexToKey(sentinel).int.storage.u64),
                 );
-                const string: String = if (has_internal_null)
+                const string = try ip.getOrPutTrailingString(
-                    @enumFromInt(string_bytes_index)
+                    gpa,
-                else
+                    @intCast(len_including_sentinel),
-                    (try ip.getOrPutTrailingString(gpa, @intCast(len_including_sentinel))).toString();
+                    .maybe_embedded_nulls,
+                );
                 ip.items.appendAssumeCapacity(.{
                     .tag = .bytes,
                     .data = ip.addExtraAssumeCapacity(Bytes{
@@ -5780,7 +5831,7 @@ pub fn get(ip: *InternPool, gpa: Allocator, key: Key) Allocator.Error!Index {
                 .tag = .memoized_call,
                 .data = ip.addExtraAssumeCapacity(MemoizedCall{
                     .func = memoized_call.func,
-                    .args_len = @as(u32, @intCast(memoized_call.arg_values.len)),
+                    .args_len = @intCast(memoized_call.arg_values.len),
                     .result = memoized_call.result,
                 }),
             });
@@ -6753,7 +6804,7 @@ fn finishFuncInstance(
     const decl = ip.declPtr(decl_index);
     decl.name = try ip.getOrPutStringFmt(gpa, "{}__anon_{d}", .{
         fn_owner_decl.name.fmt(ip), @intFromEnum(decl_index),
-    });
+    }, .no_embedded_nulls);
 
     return func_index;
 }
@@ -7216,7 +7267,7 @@ pub fn remove(ip: *InternPool, index: Index) void {
 }
 
 fn addInt(ip: *InternPool, gpa: Allocator, ty: Index, tag: Tag, limbs: []const Limb) !void {
-    const limbs_len = @as(u32, @intCast(limbs.len));
+    const limbs_len: u32 = @intCast(limbs.len);
     try ip.reserveLimbs(gpa, @typeInfo(Int).Struct.fields.len + limbs_len);
     ip.items.appendAssumeCapacity(.{
         .tag = tag,
@@ -7235,7 +7286,7 @@ fn addExtra(ip: *InternPool, gpa: Allocator, extra: anytype) Allocator.Error!u32
 }
 
 fn addExtraAssumeCapacity(ip: *InternPool, extra: anytype) u32 {
-    const result = @as(u32, @intCast(ip.extra.items.len));
+    const result: u32 = @intCast(ip.extra.items.len);
     inline for (@typeInfo(@TypeOf(extra)).Struct.fields) |field| {
         ip.extra.appendAssumeCapacity(switch (field.type) {
             Index,
@@ -7286,7 +7337,7 @@ fn addLimbsExtraAssumeCapacity(ip: *InternPool, extra: anytype) u32 {
         @sizeOf(u64) => {},
         else => @compileError("unsupported host"),
     }
-    const result = @as(u32, @intCast(ip.limbs.items.len));
+    const result: u32 = @intCast(ip.limbs.items.len);
     inline for (@typeInfo(@TypeOf(extra)).Struct.fields, 0..) |field, i| {
         const new: u32 = switch (field.type) {
             u32 => @field(extra, field.name),
@@ -7374,7 +7425,7 @@ fn limbData(ip: *const InternPool, comptime T: type, index: usize) T {
 
         @field(result, field.name) = switch (field.type) {
             u32 => int32,
-            Index => @as(Index, @enumFromInt(int32)),
+            Index => @enumFromInt(int32),
             else => @compileError("bad field type: " ++ @typeName(field.type)),
         };
     }
@@ -7410,8 +7461,8 @@ fn limbsSliceToIndex(ip: *const InternPool, limbs: []const Limb) LimbsAsIndexes
     };
     // TODO: https://github.com/ziglang/zig/issues/1738
     return .{
-        .start = @as(u32, @intCast(@divExact(@intFromPtr(limbs.ptr) - @intFromPtr(host_slice.ptr), @sizeOf(Limb)))),
+        .start = @intCast(@divExact(@intFromPtr(limbs.ptr) - @intFromPtr(host_slice.ptr), @sizeOf(Limb))),
-        .len = @as(u32, @intCast(limbs.len)),
+        .len = @intCast(limbs.len),
     };
 }
 
@@ -7683,7 +7734,7 @@ pub fn getCoerced(ip: *InternPool, gpa: Allocator, val: Index, new_ty: Index) Al
                 .val = error_union.val,
             } }),
         .aggregate => |aggregate| {
-            const new_len = @as(usize, @intCast(ip.aggregateTypeLen(new_ty)));
+            const new_len: usize = @intCast(ip.aggregateTypeLen(new_ty));
             direct: {
                 const old_ty_child = switch (ip.indexToKey(old_ty)) {
                     inline .array_type, .vector_type => |seq_type| seq_type.child,
@@ -7696,16 +7747,11 @@ pub fn getCoerced(ip: *InternPool, gpa: Allocator, val: Index, new_ty: Index) Al
                     else => unreachable,
                 };
                 if (old_ty_child != new_ty_child) break :direct;
-                // TODO: write something like getCoercedInts to avoid needing to dupe here
                 switch (aggregate.storage) {
-                    .bytes => |bytes| {
+                    .bytes => |bytes| return ip.get(gpa, .{ .aggregate = .{
-                        const bytes_copy = try gpa.dupe(u8, bytes[0..new_len]);
+                        .ty = new_ty,
-                        defer gpa.free(bytes_copy);
+                        .storage = .{ .bytes = bytes },
-                        return ip.get(gpa, .{ .aggregate = .{
+                    } }),
-                            .ty = new_ty,
-                            .storage = .{ .bytes = bytes_copy },
-                        } });
-                    },
                     .elems => |elems| {
                         const elems_copy = try gpa.dupe(Index, elems[0..new_len]);
                         defer gpa.free(elems_copy);
@@ -7729,14 +7775,13 @@ pub fn getCoerced(ip: *InternPool, gpa: Allocator, val: Index, new_ty: Index) Al
             // lifetime issues, since it'll allow us to avoid referencing `aggregate` after we
             // begin interning elems.
             switch (aggregate.storage) {
-                .bytes => {
+                .bytes => |bytes| {
                     // We have to intern each value here, so unfortunately we can't easily avoid
                     // the repeated indexToKey calls.
-                    for (agg_elems, 0..) |*elem, i| {
+                    for (agg_elems, 0..) |*elem, index| {
-                        const x = ip.indexToKey(val).aggregate.storage.bytes[i];
                         elem.* = try ip.get(gpa, .{ .int = .{
                             .ty = .u8_type,
-                            .storage = .{ .u64 = x },
+                            .storage = .{ .u64 = bytes.at(index, ip) },
                         } });
                     }
                 },
@@ -8169,9 +8214,8 @@ fn dumpStatsFallible(ip: *const InternPool, arena: Allocator) anyerror!void {
 
             .bytes => b: {
                 const info = ip.extraData(Bytes, data);
-                const len = @as(u32, @intCast(ip.aggregateTypeLenIncludingSentinel(info.ty)));
+                const len: usize = @intCast(ip.aggregateTypeLenIncludingSentinel(info.ty));
-                break :b @sizeOf(Bytes) + len +
+                break :b @sizeOf(Bytes) + len + @intFromBool(info.bytes.at(len - 1, ip) != 0);
-                    @intFromBool(ip.string_bytes.items[@intFromEnum(info.bytes) + len - 1] != 0);
             },
             .aggregate => b: {
                 const info = ip.extraData(Tag.Aggregate, data);
@@ -8434,15 +8478,35 @@ pub fn destroyNamespace(ip: *InternPool, gpa: Allocator, index: NamespaceIndex)
     };
 }
 
+const EmbeddedNulls = enum {
+    no_embedded_nulls,
+    maybe_embedded_nulls,
+
+    fn StringType(comptime embedded_nulls: EmbeddedNulls) type {
+        return switch (embedded_nulls) {
+            .no_embedded_nulls => NullTerminatedString,
+            .maybe_embedded_nulls => String,
+        };
+    }
+
+    fn OptionalStringType(comptime embedded_nulls: EmbeddedNulls) type {
+        return switch (embedded_nulls) {
+            .no_embedded_nulls => OptionalNullTerminatedString,
+            .maybe_embedded_nulls => OptionalString,
+        };
+    }
+};
+
 pub fn getOrPutString(
     ip: *InternPool,
     gpa: Allocator,
-    s: []const u8,
+    slice: []const u8,
-) Allocator.Error!NullTerminatedString {
+    comptime embedded_nulls: EmbeddedNulls,
-    try ip.string_bytes.ensureUnusedCapacity(gpa, s.len + 1);
+) Allocator.Error!embedded_nulls.StringType() {
-    ip.string_bytes.appendSliceAssumeCapacity(s);
+    try ip.string_bytes.ensureUnusedCapacity(gpa, slice.len + 1);
+    ip.string_bytes.appendSliceAssumeCapacity(slice);
     ip.string_bytes.appendAssumeCapacity(0);
-    return ip.getOrPutTrailingString(gpa, s.len + 1);
+    return ip.getOrPutTrailingString(gpa, slice.len + 1, embedded_nulls);
 }
 
 pub fn getOrPutStringFmt(
@@ -8450,23 +8514,24 @@ pub fn getOrPutStringFmt(
     gpa: Allocator,
     comptime format: []const u8,
     args: anytype,
-) Allocator.Error!NullTerminatedString {
+    comptime embedded_nulls: EmbeddedNulls,
+) Allocator.Error!embedded_nulls.StringType() {
     // ensure that references to string_bytes in args do not get invalidated
     const len: usize = @intCast(std.fmt.count(format, args) + 1);
     try ip.string_bytes.ensureUnusedCapacity(gpa, len);
     ip.string_bytes.writer(undefined).print(format, args) catch unreachable;
     ip.string_bytes.appendAssumeCapacity(0);
-    return ip.getOrPutTrailingString(gpa, len);
+    return ip.getOrPutTrailingString(gpa, len, embedded_nulls);
 }
 
 pub fn getOrPutStringOpt(
     ip: *InternPool,
     gpa: Allocator,
-    optional_string: ?[]const u8,
+    slice: ?[]const u8,
-) Allocator.Error!OptionalNullTerminatedString {
+    comptime embedded_nulls: EmbeddedNulls,
-    const s = optional_string orelse return .none;
+) Allocator.Error!embedded_nulls.OptionalStringType() {
-    const interned = try getOrPutString(ip, gpa, s);
+    const string = try getOrPutString(ip, gpa, slice orelse return .none, embedded_nulls);
-    return interned.toOptional();
+    return string.toOptional();
 }
 
 /// Uses the last len bytes of ip.string_bytes as the key.
@@ -8474,7 +8539,8 @@ pub fn getOrPutTrailingString(
     ip: *InternPool,
     gpa: Allocator,
     len: usize,
-) Allocator.Error!NullTerminatedString {
+    comptime embedded_nulls: EmbeddedNulls,
+) Allocator.Error!embedded_nulls.StringType() {
     const string_bytes = &ip.string_bytes;
     const str_index: u32 = @intCast(string_bytes.items.len - len);
     if (len > 0 and string_bytes.getLast() == 0) {
@@ -8483,6 +8549,14 @@ pub fn getOrPutTrailingString(
         try string_bytes.ensureUnusedCapacity(gpa, 1);
     }
     const key: []const u8 = string_bytes.items[str_index..];
+    const has_embedded_null = std.mem.indexOfScalar(u8, key, 0) != null;
+    switch (embedded_nulls) {
+        .no_embedded_nulls => assert(!has_embedded_null),
+        .maybe_embedded_nulls => if (has_embedded_null) {
+            string_bytes.appendAssumeCapacity(0);
+            return @enumFromInt(str_index);
+        },
+    }
     const gop = try ip.string_table.getOrPutContextAdapted(gpa, key, std.hash_map.StringIndexAdapter{
         .bytes = string_bytes,
     }, std.hash_map.StringIndexContext{
@@ -8498,58 +8572,10 @@ pub fn getOrPutTrailingString(
     }
 }
 
-/// Uses the last len bytes of ip.string_bytes as the key.
-pub fn getTrailingAggregate(
-    ip: *InternPool,
-    gpa: Allocator,
-    ty: Index,
-    len: usize,
-) Allocator.Error!Index {
-    try ip.items.ensureUnusedCapacity(gpa, 1);
-    try ip.extra.ensureUnusedCapacity(gpa, @typeInfo(Bytes).Struct.fields.len);
-
-    const str: String = @enumFromInt(ip.string_bytes.items.len - len);
-    const adapter: KeyAdapter = .{ .intern_pool = ip };
-    const gop = try ip.map.getOrPutAdapted(gpa, Key{ .aggregate = .{
-        .ty = ty,
-        .storage = .{ .bytes = ip.string_bytes.items[@intFromEnum(str)..] },
-    } }, adapter);
-    if (gop.found_existing) return @enumFromInt(gop.index);
-
-    ip.items.appendAssumeCapacity(.{
-        .tag = .bytes,
-        .data = ip.addExtraAssumeCapacity(Bytes{
-            .ty = ty,
-            .bytes = str,
-        }),
-    });
-    return @enumFromInt(ip.items.len - 1);
-}
-
 pub fn getString(ip: *InternPool, s: []const u8) OptionalNullTerminatedString {
-    if (ip.string_table.getKeyAdapted(s, std.hash_map.StringIndexAdapter{
+    return if (ip.string_table.getKeyAdapted(s, std.hash_map.StringIndexAdapter{
         .bytes = &ip.string_bytes,
-    })) |index| {
+    })) |index| @enumFromInt(index) else .none;
-        return @as(NullTerminatedString, @enumFromInt(index)).toOptional();
-    } else {
-        return .none;
-    }
-}
-
-pub fn stringToSlice(ip: *const InternPool, s: NullTerminatedString) [:0]const u8 {
-    const string_bytes = ip.string_bytes.items;
-    const start = @intFromEnum(s);
-    var end: usize = start;
-    while (string_bytes[end] != 0) end += 1;
-    return string_bytes[start..end :0];
-}
-
-pub fn stringToSliceUnwrap(ip: *const InternPool, s: OptionalNullTerminatedString) ?[:0]const u8 {
-    return ip.stringToSlice(s.unwrap() orelse return null);
-}
-
-pub fn stringEqlSlice(ip: *const InternPool, a: NullTerminatedString, b: []const u8) bool {
-    return std.mem.eql(u8, stringToSlice(ip, a), b);
 }
 
 pub fn typeOf(ip: *const InternPool, index: Index) Index {
@@ -8767,7 +8793,7 @@ pub fn aggregateTypeLenIncludingSentinel(ip: *const InternPool, ty: Index) u64 {
     return switch (ip.indexToKey(ty)) {
         .struct_type => ip.loadStructType(ty).field_types.len,
         .anon_struct_type => |anon_struct_type| anon_struct_type.types.len,
-        .array_type => |array_type| array_type.len + @intFromBool(array_type.sentinel != .none),
+        .array_type => |array_type| array_type.lenIncludingSentinel(),
         .vector_type => |vector_type| vector_type.len,
         else => unreachable,
     };

src/Module.zig

@@ -763,11 +763,11 @@ pub const Namespace = struct {
     ) !InternPool.NullTerminatedString {
         const ip = &zcu.intern_pool;
         const count = count: {
-            var count: usize = ip.stringToSlice(name).len + 1;
+            var count: usize = name.length(ip) + 1;
             var cur_ns = &ns;
             while (true) {
                 const decl = zcu.declPtr(cur_ns.decl_index);
-                count += ip.stringToSlice(decl.name).len + 1;
+                count += decl.name.length(ip) + 1;
                 cur_ns = zcu.namespacePtr(cur_ns.parent.unwrap() orelse {
                     count += ns.file_scope.sub_file_path.len;
                     break :count count;
@@ -793,7 +793,7 @@ pub const Namespace = struct {
             };
         }
 
-        return ip.getOrPutTrailingString(gpa, ip.string_bytes.items.len - start);
+        return ip.getOrPutTrailingString(gpa, ip.string_bytes.items.len - start, .no_embedded_nulls);
     }
 
     pub fn getType(ns: Namespace, zcu: *Zcu) Type {
@@ -980,17 +980,13 @@ pub const File = struct {
         const ip = &mod.intern_pool;
         const start = ip.string_bytes.items.len;
         try file.renderFullyQualifiedName(ip.string_bytes.writer(mod.gpa));
-        return ip.getOrPutTrailingString(mod.gpa, ip.string_bytes.items.len - start);
+        return ip.getOrPutTrailingString(mod.gpa, ip.string_bytes.items.len - start, .no_embedded_nulls);
     }
 
     pub fn fullPath(file: File, ally: Allocator) ![]u8 {
         return file.mod.root.joinString(ally, file.sub_file_path);
     }
 
-    pub fn fullPathZ(file: File, ally: Allocator) ![:0]u8 {
-        return file.mod.root.joinStringZ(ally, file.sub_file_path);
-    }
-
     pub fn dumpSrc(file: *File, src: LazySrcLoc) void {
         const loc = std.zig.findLineColumn(file.source.bytes, src);
         std.debug.print("{s}:{d}:{d}\n", .{ file.sub_file_path, loc.line + 1, loc.column + 1 });
@@ -2534,6 +2530,7 @@ fn updateZirRefs(zcu: *Module, file: *File, old_zir: Zir) !void {
                 const name_ip = try zcu.intern_pool.getOrPutString(
                     zcu.gpa,
                     old_zir.nullTerminatedString(name_zir),
+                    .no_embedded_nulls,
                 );
                 try old_names.put(zcu.gpa, name_ip, {});
             }
@@ -2551,6 +2548,7 @@ fn updateZirRefs(zcu: *Module, file: *File, old_zir: Zir) !void {
                 const name_ip = try zcu.intern_pool.getOrPutString(
                     zcu.gpa,
                     old_zir.nullTerminatedString(name_zir),
+                    .no_embedded_nulls,
                 );
                 if (!old_names.swapRemove(name_ip)) continue;
                 // Name added
@@ -3555,37 +3553,46 @@ fn semaDecl(mod: *Module, decl_index: Decl.Index) !SemaDeclResult {
     const gpa = mod.gpa;
     const zir = decl.getFileScope(mod).zir;
 
-    const builtin_type_target_index: InternPool.Index = blk: {
+    const builtin_type_target_index: InternPool.Index = ip_index: {
         const std_mod = mod.std_mod;
-        if (decl.getFileScope(mod).mod != std_mod) break :blk .none;
+        if (decl.getFileScope(mod).mod != std_mod) break :ip_index .none;
         // We're in the std module.
         const std_file = (try mod.importPkg(std_mod)).file;
         const std_decl = mod.declPtr(std_file.root_decl.unwrap().?);
         const std_namespace = std_decl.getInnerNamespace(mod).?;
-        const builtin_str = try ip.getOrPutString(gpa, "builtin");
+        const builtin_str = try ip.getOrPutString(gpa, "builtin", .no_embedded_nulls);
-        const builtin_decl = mod.declPtr(std_namespace.decls.getKeyAdapted(builtin_str, DeclAdapter{ .zcu = mod }) orelse break :blk .none);
+        const builtin_decl = mod.declPtr(std_namespace.decls.getKeyAdapted(builtin_str, DeclAdapter{ .zcu = mod }) orelse break :ip_index .none);
-        const builtin_namespace = builtin_decl.getInnerNamespaceIndex(mod).unwrap() orelse break :blk .none;
+        const builtin_namespace = builtin_decl.getInnerNamespaceIndex(mod).unwrap() orelse break :ip_index .none;
-        if (decl.src_namespace != builtin_namespace) break :blk .none;
+        if (decl.src_namespace != builtin_namespace) break :ip_index .none;
         // We're in builtin.zig. This could be a builtin we need to add to a specific InternPool index.
-        for ([_]struct { []const u8, InternPool.Index }{
+        for ([_][]const u8{
-            .{ "AtomicOrder", .atomic_order_type },
+            "AtomicOrder",
-            .{ "AtomicRmwOp", .atomic_rmw_op_type },
+            "AtomicRmwOp",
-            .{ "CallingConvention", .calling_convention_type },
+            "CallingConvention",
-            .{ "AddressSpace", .address_space_type },
+            "AddressSpace",
-            .{ "FloatMode", .float_mode_type },
+            "FloatMode",
-            .{ "ReduceOp", .reduce_op_type },
+            "ReduceOp",
-            .{ "CallModifier", .call_modifier_type },
+            "CallModifier",
-            .{ "PrefetchOptions", .prefetch_options_type },
+            "PrefetchOptions",
-            .{ "ExportOptions", .export_options_type },
+            "ExportOptions",
-            .{ "ExternOptions", .extern_options_type },
+            "ExternOptions",
-            .{ "Type", .type_info_type },
+            "Type",
-        }) |pair| {
+        }, [_]InternPool.Index{
-            const decl_name = ip.stringToSlice(decl.name);
+            .atomic_order_type,
-            if (std.mem.eql(u8, decl_name, pair[0])) {
+            .atomic_rmw_op_type,
-                break :blk pair[1];
+            .calling_convention_type,
-            }
+            .address_space_type,
+            .float_mode_type,
+            .reduce_op_type,
+            .call_modifier_type,
+            .prefetch_options_type,
+            .export_options_type,
+            .extern_options_type,
+            .type_info_type,
+        }) |type_name, type_ip| {
+            if (decl.name.eqlSlice(type_name, ip)) break :ip_index type_ip;
         }
-        break :blk .none;
+        break :ip_index .none;
     };
 
     mod.intern_pool.removeDependenciesForDepender(gpa, InternPool.Depender.wrap(.{ .decl = decl_index }));
@@ -3725,8 +3732,7 @@ fn semaDecl(mod: *Module, decl_index: Decl.Index) !SemaDeclResult {
             } else if (bytes.len == 0) {
                 return sema.fail(&block_scope, section_src, "linksection cannot be empty", .{});
             }
-            const section = try ip.getOrPutString(gpa, bytes);
+            break :blk try ip.getOrPutStringOpt(gpa, bytes, .no_embedded_nulls);
-            break :blk section.toOptional();
         };
         decl.@"addrspace" = blk: {
             const addrspace_ctx: Sema.AddressSpaceContext = switch (ip.indexToKey(decl_val.toIntern())) {
@@ -4101,7 +4107,10 @@ fn newEmbedFile(
         .sentinel = .zero_u8,
         .child = .u8_type,
     } });
-    const array_val = try ip.getTrailingAggregate(gpa, array_ty, bytes.len);
+    const array_val = try ip.get(gpa, .{ .aggregate = .{
+        .ty = array_ty,
+        .storage = .{ .bytes = try ip.getOrPutTrailingString(gpa, bytes.len, .maybe_embedded_nulls) },
+    } });
 
     const ptr_ty = (try mod.ptrType(.{
         .child = array_ty,
@@ -4111,7 +4120,6 @@ fn newEmbedFile(
             .address_space = .generic,
         },
     })).toIntern();
-
     const ptr_val = try ip.get(gpa, .{ .ptr = .{
         .ty = ptr_ty,
         .addr = .{ .anon_decl = .{
@@ -4122,7 +4130,7 @@ fn newEmbedFile(
 
     result.* = new_file;
     new_file.* = .{
-        .sub_file_path = try ip.getOrPutString(gpa, sub_file_path),
+        .sub_file_path = try ip.getOrPutString(gpa, sub_file_path, .no_embedded_nulls),
         .owner = pkg,
         .stat = stat,
         .val = ptr_val,
@@ -4214,11 +4222,11 @@ const ScanDeclIter = struct {
         const zcu = iter.zcu;
         const gpa = zcu.gpa;
         const ip = &zcu.intern_pool;
-        var name = try ip.getOrPutStringFmt(gpa, fmt, args);
+        var name = try ip.getOrPutStringFmt(gpa, fmt, args, .no_embedded_nulls);
         var gop = try iter.seen_decls.getOrPut(gpa, name);
         var next_suffix: u32 = 0;
         while (gop.found_existing) {
-            name = try ip.getOrPutStringFmt(gpa, fmt ++ "_{d}", args ++ .{next_suffix});
+            name = try ip.getOrPutStringFmt(gpa, "{}_{d}", .{ name.fmt(ip), next_suffix }, .no_embedded_nulls);
             gop = try iter.seen_decls.getOrPut(gpa, name);
             next_suffix += 1;
         }
@@ -4300,7 +4308,11 @@ fn scanDecl(iter: *ScanDeclIter, decl_inst: Zir.Inst.Index) Allocator.Error!void
             };
         } else info: {
             if (iter.pass != .named) return;
-            const name = try ip.getOrPutString(gpa, zir.nullTerminatedString(declaration.name.toString(zir).?));
+            const name = try ip.getOrPutString(
+                gpa,
+                zir.nullTerminatedString(declaration.name.toString(zir).?),
+                .no_embedded_nulls,
+            );
             try iter.seen_decls.putNoClobber(gpa, name, {});
             break :info .{
                 name,
@@ -4362,9 +4374,10 @@ fn scanDecl(iter: *ScanDeclIter, decl_inst: Zir.Inst.Index) Allocator.Error!void
             if (!comp.config.is_test) break :a false;
             if (decl_mod != zcu.main_mod) break :a false;
             if (is_named_test and comp.test_filters.len > 0) {
-                const decl_fqn = ip.stringToSlice(try namespace.fullyQualifiedName(zcu, decl_name));
+                const decl_fqn = try namespace.fullyQualifiedName(zcu, decl_name);
+                const decl_fqn_slice = decl_fqn.toSlice(ip);
                 for (comp.test_filters) |test_filter| {
-                    if (mem.indexOf(u8, decl_fqn, test_filter)) |_| break;
+                    if (mem.indexOf(u8, decl_fqn_slice, test_filter)) |_| break;
                 } else break :a false;
             }
             zcu.test_functions.putAssumeCapacity(decl_index, {}); // may clobber on incremental update
@@ -4377,8 +4390,8 @@ fn scanDecl(iter: *ScanDeclIter, decl_inst: Zir.Inst.Index) Allocator.Error!void
         // `is_export` is unchanged. In this case, the incremental update mechanism will handle
         // re-analysis for us if necessary.
         if (prev_exported != declaration.flags.is_export or decl.analysis == .unreferenced) {
-            log.debug("scanDecl queue analyze_decl file='{s}' decl_name='{s}' decl_index={d}", .{
+            log.debug("scanDecl queue analyze_decl file='{s}' decl_name='{}' decl_index={d}", .{
-                namespace.file_scope.sub_file_path, ip.stringToSlice(decl_name), decl_index,
+                namespace.file_scope.sub_file_path, decl_name.fmt(ip), decl_index,
             });
             comp.work_queue.writeItemAssumeCapacity(.{ .analyze_decl = decl_index });
         }
@@ -5300,7 +5313,7 @@ pub fn populateTestFunctions(
     const builtin_file = (mod.importPkg(builtin_mod) catch unreachable).file;
     const root_decl = mod.declPtr(builtin_file.root_decl.unwrap().?);
     const builtin_namespace = mod.namespacePtr(root_decl.src_namespace);
-    const test_functions_str = try ip.getOrPutString(gpa, "test_functions");
+    const test_functions_str = try ip.getOrPutString(gpa, "test_functions", .no_embedded_nulls);
     const decl_index = builtin_namespace.decls.getKeyAdapted(
         test_functions_str,
         DeclAdapter{ .zcu = mod },
@@ -5327,16 +5340,16 @@ pub fn populateTestFunctions(
 
         for (test_fn_vals, mod.test_functions.keys()) |*test_fn_val, test_decl_index| {
             const test_decl = mod.declPtr(test_decl_index);
-            const test_decl_name = try gpa.dupe(u8, ip.stringToSlice(try test_decl.fullyQualifiedName(mod)));
+            const test_decl_name = try test_decl.fullyQualifiedName(mod);
-            defer gpa.free(test_decl_name);
+            const test_decl_name_len = test_decl_name.length(ip);
             const test_name_anon_decl: InternPool.Key.Ptr.Addr.AnonDecl = n: {
                 const test_name_ty = try mod.arrayType(.{
-                    .len = test_decl_name.len,
+                    .len = test_decl_name_len,
                     .child = .u8_type,
                 });
                 const test_name_val = try mod.intern(.{ .aggregate = .{
                     .ty = test_name_ty.toIntern(),
-                    .storage = .{ .bytes = test_decl_name },
+                    .storage = .{ .bytes = test_decl_name.toString() },
                 } });
                 break :n .{
                     .orig_ty = (try mod.singleConstPtrType(test_name_ty)).toIntern(),
@@ -5354,7 +5367,7 @@ pub fn populateTestFunctions(
                     } }),
                     .len = try mod.intern(.{ .int = .{
                         .ty = .usize_type,
-                        .storage = .{ .u64 = test_decl_name.len },
+                        .storage = .{ .u64 = test_decl_name_len },
                     } }),
                 } }),
                 // func

src/Value.zig

@@ -52,30 +52,31 @@ pub fn toIpString(val: Value, ty: Type, mod: *Module) !InternPool.NullTerminated
     assert(ty.zigTypeTag(mod) == .Array);
     assert(ty.childType(mod).toIntern() == .u8_type);
     const ip = &mod.intern_pool;
-    return switch (mod.intern_pool.indexToKey(val.toIntern()).aggregate.storage) {
+    switch (mod.intern_pool.indexToKey(val.toIntern()).aggregate.storage) {
-        .bytes => |bytes| try ip.getOrPutString(mod.gpa, bytes),
+        .bytes => |bytes| return bytes.toNullTerminatedString(ty.arrayLen(mod), ip),
-        .elems => try arrayToIpString(val, ty.arrayLen(mod), mod),
+        .elems => return arrayToIpString(val, ty.arrayLen(mod), mod),
         .repeated_elem => |elem| {
-            const byte = @as(u8, @intCast(Value.fromInterned(elem).toUnsignedInt(mod)));
+            const byte: u8 = @intCast(Value.fromInterned(elem).toUnsignedInt(mod));
-            const len = @as(usize, @intCast(ty.arrayLen(mod)));
+            const len: usize = @intCast(ty.arrayLen(mod));
             try ip.string_bytes.appendNTimes(mod.gpa, byte, len);
-            return ip.getOrPutTrailingString(mod.gpa, len);
+            return ip.getOrPutTrailingString(mod.gpa, len, .no_embedded_nulls);
         },
-    };
+    }
 }
 
 /// Asserts that the value is representable as an array of bytes.
 /// Copies the value into a freshly allocated slice of memory, which is owned by the caller.
 pub fn toAllocatedBytes(val: Value, ty: Type, allocator: Allocator, mod: *Module) ![]u8 {
-    return switch (mod.intern_pool.indexToKey(val.toIntern())) {
+    const ip = &mod.intern_pool;
-        .enum_literal => |enum_literal| allocator.dupe(u8, mod.intern_pool.stringToSlice(enum_literal)),
+    return switch (ip.indexToKey(val.toIntern())) {
+        .enum_literal => |enum_literal| allocator.dupe(u8, enum_literal.toSlice(ip)),
         .slice => |slice| try arrayToAllocatedBytes(val, Value.fromInterned(slice.len).toUnsignedInt(mod), allocator, mod),
         .aggregate => |aggregate| switch (aggregate.storage) {
-            .bytes => |bytes| try allocator.dupe(u8, bytes),
+            .bytes => |bytes| try allocator.dupe(u8, bytes.toSlice(ty.arrayLenIncludingSentinel(mod), ip)),
             .elems => try arrayToAllocatedBytes(val, ty.arrayLen(mod), allocator, mod),
             .repeated_elem => |elem| {
-                const byte = @as(u8, @intCast(Value.fromInterned(elem).toUnsignedInt(mod)));
+                const byte: u8 = @intCast(Value.fromInterned(elem).toUnsignedInt(mod));
-                const result = try allocator.alloc(u8, @as(usize, @intCast(ty.arrayLen(mod))));
+                const result = try allocator.alloc(u8, @intCast(ty.arrayLen(mod)));
                 @memset(result, byte);
                 return result;
             },
@@ -85,10 +86,10 @@ pub fn toAllocatedBytes(val: Value, ty: Type, allocator: Allocator, mod: *Module
 }
 
 fn arrayToAllocatedBytes(val: Value, len: u64, allocator: Allocator, mod: *Module) ![]u8 {
-    const result = try allocator.alloc(u8, @as(usize, @intCast(len)));
+    const result = try allocator.alloc(u8, @intCast(len));
     for (result, 0..) |*elem, i| {
         const elem_val = try val.elemValue(mod, i);
-        elem.* = @as(u8, @intCast(elem_val.toUnsignedInt(mod)));
+        elem.* = @intCast(elem_val.toUnsignedInt(mod));
     }
     return result;
 }
@@ -96,7 +97,7 @@ fn arrayToAllocatedBytes(val: Value, len: u64, allocator: Allocator, mod: *Modul
 fn arrayToIpString(val: Value, len_u64: u64, mod: *Module) !InternPool.NullTerminatedString {
     const gpa = mod.gpa;
     const ip = &mod.intern_pool;
-    const len = @as(usize, @intCast(len_u64));
+    const len: usize = @intCast(len_u64);
     try ip.string_bytes.ensureUnusedCapacity(gpa, len);
     for (0..len) |i| {
         // I don't think elemValue has the possibility to affect ip.string_bytes. Let's
@@ -104,10 +105,10 @@ fn arrayToIpString(val: Value, len_u64: u64, mod: *Module) !InternPool.NullTermi
         const prev = ip.string_bytes.items.len;
         const elem_val = try val.elemValue(mod, i);
         assert(ip.string_bytes.items.len == prev);
-        const byte = @as(u8, @intCast(elem_val.toUnsignedInt(mod)));
+        const byte: u8 = @intCast(elem_val.toUnsignedInt(mod));
         ip.string_bytes.appendAssumeCapacity(byte);
     }
-    return ip.getOrPutTrailingString(gpa, len);
+    return ip.getOrPutTrailingString(gpa, len, .no_embedded_nulls);
 }
 
 pub fn fromInterned(i: InternPool.Index) Value {
@@ -256,7 +257,7 @@ pub fn getUnsignedIntAdvanced(val: Value, mod: *Module, opt_sema: ?*Sema) !?u64
                     const base_addr = (try Value.fromInterned(field.base).getUnsignedIntAdvanced(mod, opt_sema)) orelse return null;
                     const struct_ty = Value.fromInterned(field.base).typeOf(mod).childType(mod);
                     if (opt_sema) |sema| try sema.resolveTypeLayout(struct_ty);
-                    return base_addr + struct_ty.structFieldOffset(@as(usize, @intCast(field.index)), mod);
+                    return base_addr + struct_ty.structFieldOffset(@intCast(field.index), mod);
                 },
                 else => null,
             },
@@ -351,17 +352,17 @@ pub fn writeToMemory(val: Value, ty: Type, mod: *Module, buffer: []u8) error{
             bigint.writeTwosComplement(buffer[0..byte_count], endian);
         },
         .Float => switch (ty.floatBits(target)) {
-            16 => std.mem.writeInt(u16, buffer[0..2], @as(u16, @bitCast(val.toFloat(f16, mod))), endian),
+            16 => std.mem.writeInt(u16, buffer[0..2], @bitCast(val.toFloat(f16, mod)), endian),
-            32 => std.mem.writeInt(u32, buffer[0..4], @as(u32, @bitCast(val.toFloat(f32, mod))), endian),
+            32 => std.mem.writeInt(u32, buffer[0..4], @bitCast(val.toFloat(f32, mod)), endian),
-            64 => std.mem.writeInt(u64, buffer[0..8], @as(u64, @bitCast(val.toFloat(f64, mod))), endian),
+            64 => std.mem.writeInt(u64, buffer[0..8], @bitCast(val.toFloat(f64, mod)), endian),
-            80 => std.mem.writeInt(u80, buffer[0..10], @as(u80, @bitCast(val.toFloat(f80, mod))), endian),
+            80 => std.mem.writeInt(u80, buffer[0..10], @bitCast(val.toFloat(f80, mod)), endian),
-            128 => std.mem.writeInt(u128, buffer[0..16], @as(u128, @bitCast(val.toFloat(f128, mod))), endian),
+            128 => std.mem.writeInt(u128, buffer[0..16], @bitCast(val.toFloat(f128, mod)), endian),
             else => unreachable,
         },
         .Array => {
             const len = ty.arrayLen(mod);
             const elem_ty = ty.childType(mod);
-            const elem_size = @as(usize, @intCast(elem_ty.abiSize(mod)));
+            const elem_size: usize = @intCast(elem_ty.abiSize(mod));
             var elem_i: usize = 0;
             var buf_off: usize = 0;
             while (elem_i < len) : (elem_i += 1) {
@@ -380,17 +381,17 @@ pub fn writeToMemory(val: Value, ty: Type, mod: *Module, buffer: []u8) error{
             const struct_type = mod.typeToStruct(ty) orelse return error.IllDefinedMemoryLayout;
             switch (struct_type.layout) {
                 .auto => return error.IllDefinedMemoryLayout,
-                .@"extern" => for (0..struct_type.field_types.len) |i| {
+                .@"extern" => for (0..struct_type.field_types.len) |field_index| {
-                    const off: usize = @intCast(ty.structFieldOffset(i, mod));
+                    const off: usize = @intCast(ty.structFieldOffset(field_index, mod));
                     const field_val = Value.fromInterned(switch (ip.indexToKey(val.toIntern()).aggregate.storage) {
                         .bytes => |bytes| {
-                            buffer[off] = bytes[i];
+                            buffer[off] = bytes.at(field_index, ip);
                             continue;
                         },
-                        .elems => |elems| elems[i],
+                        .elems => |elems| elems[field_index],
                         .repeated_elem => |elem| elem,
                     });
-                    const field_ty = Type.fromInterned(struct_type.field_types.get(ip)[i]);
+                    const field_ty = Type.fromInterned(struct_type.field_types.get(ip)[field_index]);
                     try writeToMemory(field_val, field_ty, mod, buffer[off..]);
                 },
                 .@"packed" => {
@@ -423,7 +424,7 @@ pub fn writeToMemory(val: Value, ty: Type, mod: *Module, buffer: []u8) error{
                     const field_index = mod.unionTagFieldIndex(union_obj, union_tag).?;
                     const field_type = Type.fromInterned(union_obj.field_types.get(&mod.intern_pool)[field_index]);
                     const field_val = try val.fieldValue(mod, field_index);
-                    const byte_count = @as(usize, @intCast(field_type.abiSize(mod)));
+                    const byte_count: usize = @intCast(field_type.abiSize(mod));
                     return writeToMemory(field_val, field_type, mod, buffer[0..byte_count]);
                 } else {
                     const backing_ty = try ty.unionBackingType(mod);
@@ -471,7 +472,7 @@ pub fn writeToPackedMemory(
     const target = mod.getTarget();
     const endian = target.cpu.arch.endian();
     if (val.isUndef(mod)) {
-        const bit_size = @as(usize, @intCast(ty.bitSize(mod)));
+        const bit_size: usize = @intCast(ty.bitSize(mod));
         std.mem.writeVarPackedInt(buffer, bit_offset, bit_size, @as(u1, 0), endian);
         return;
     }
@@ -507,17 +508,17 @@ pub fn writeToPackedMemory(
             }
         },
         .Float => switch (ty.floatBits(target)) {
-            16 => std.mem.writePackedInt(u16, buffer, bit_offset, @as(u16, @bitCast(val.toFloat(f16, mod))), endian),
+            16 => std.mem.writePackedInt(u16, buffer, bit_offset, @bitCast(val.toFloat(f16, mod)), endian),
-            32 => std.mem.writePackedInt(u32, buffer, bit_offset, @as(u32, @bitCast(val.toFloat(f32, mod))), endian),
+            32 => std.mem.writePackedInt(u32, buffer, bit_offset, @bitCast(val.toFloat(f32, mod)), endian),
-            64 => std.mem.writePackedInt(u64, buffer, bit_offset, @as(u64, @bitCast(val.toFloat(f64, mod))), endian),
+            64 => std.mem.writePackedInt(u64, buffer, bit_offset, @bitCast(val.toFloat(f64, mod)), endian),
-            80 => std.mem.writePackedInt(u80, buffer, bit_offset, @as(u80, @bitCast(val.toFloat(f80, mod))), endian),
+            80 => std.mem.writePackedInt(u80, buffer, bit_offset, @bitCast(val.toFloat(f80, mod)), endian),
-            128 => std.mem.writePackedInt(u128, buffer, bit_offset, @as(u128, @bitCast(val.toFloat(f128, mod))), endian),
+            128 => std.mem.writePackedInt(u128, buffer, bit_offset, @bitCast(val.toFloat(f128, mod)), endian),
             else => unreachable,
         },
         .Vector => {
             const elem_ty = ty.childType(mod);
-            const elem_bit_size = @as(u16, @intCast(elem_ty.bitSize(mod)));
+            const elem_bit_size: u16 = @intCast(elem_ty.bitSize(mod));
-            const len = @as(usize, @intCast(ty.arrayLen(mod)));
+            const len: usize = @intCast(ty.arrayLen(mod));
 
             var bits: u16 = 0;
             var elem_i: usize = 0;
@@ -644,22 +645,22 @@ pub fn readFromMemory(
         .Float => return Value.fromInterned((try mod.intern(.{ .float = .{
             .ty = ty.toIntern(),
             .storage = switch (ty.floatBits(target)) {
-                16 => .{ .f16 = @as(f16, @bitCast(std.mem.readInt(u16, buffer[0..2], endian))) },
+                16 => .{ .f16 = @bitCast(std.mem.readInt(u16, buffer[0..2], endian)) },
-                32 => .{ .f32 = @as(f32, @bitCast(std.mem.readInt(u32, buffer[0..4], endian))) },
+                32 => .{ .f32 = @bitCast(std.mem.readInt(u32, buffer[0..4], endian)) },
-                64 => .{ .f64 = @as(f64, @bitCast(std.mem.readInt(u64, buffer[0..8], endian))) },
+                64 => .{ .f64 = @bitCast(std.mem.readInt(u64, buffer[0..8], endian)) },
-                80 => .{ .f80 = @as(f80, @bitCast(std.mem.readInt(u80, buffer[0..10], endian))) },
+                80 => .{ .f80 = @bitCast(std.mem.readInt(u80, buffer[0..10], endian)) },
-                128 => .{ .f128 = @as(f128, @bitCast(std.mem.readInt(u128, buffer[0..16], endian))) },
+                128 => .{ .f128 = @bitCast(std.mem.readInt(u128, buffer[0..16], endian)) },
                 else => unreachable,
             },
         } }))),
         .Array => {
             const elem_ty = ty.childType(mod);
             const elem_size = elem_ty.abiSize(mod);
-            const elems = try arena.alloc(InternPool.Index, @as(usize, @intCast(ty.arrayLen(mod))));
+            const elems = try arena.alloc(InternPool.Index, @intCast(ty.arrayLen(mod)));
             var offset: usize = 0;
             for (elems) |*elem| {
                 elem.* = (try readFromMemory(elem_ty, mod, buffer[offset..], arena)).toIntern();
-                offset += @as(usize, @intCast(elem_size));
+                offset += @intCast(elem_size);
             }
             return Value.fromInterned((try mod.intern(.{ .aggregate = .{
                 .ty = ty.toIntern(),
@@ -795,7 +796,7 @@ pub fn readFromPackedMemory(
             };
 
             // Slow path, we have to construct a big-int
-            const abi_size = @as(usize, @intCast(ty.abiSize(mod)));
+            const abi_size: usize = @intCast(ty.abiSize(mod));
             const Limb = std.math.big.Limb;
             const limb_count = (abi_size + @sizeOf(Limb) - 1) / @sizeOf(Limb);
             const limbs_buffer = try arena.alloc(Limb, limb_count);
@@ -812,20 +813,20 @@ pub fn readFromPackedMemory(
         .Float => return Value.fromInterned((try mod.intern(.{ .float = .{
             .ty = ty.toIntern(),
             .storage = switch (ty.floatBits(target)) {
-                16 => .{ .f16 = @as(f16, @bitCast(std.mem.readPackedInt(u16, buffer, bit_offset, endian))) },
+                16 => .{ .f16 = @bitCast(std.mem.readPackedInt(u16, buffer, bit_offset, endian)) },
-                32 => .{ .f32 = @as(f32, @bitCast(std.mem.readPackedInt(u32, buffer, bit_offset, endian))) },
+                32 => .{ .f32 = @bitCast(std.mem.readPackedInt(u32, buffer, bit_offset, endian)) },
-                64 => .{ .f64 = @as(f64, @bitCast(std.mem.readPackedInt(u64, buffer, bit_offset, endian))) },
+                64 => .{ .f64 = @bitCast(std.mem.readPackedInt(u64, buffer, bit_offset, endian)) },
-                80 => .{ .f80 = @as(f80, @bitCast(std.mem.readPackedInt(u80, buffer, bit_offset, endian))) },
+                80 => .{ .f80 = @bitCast(std.mem.readPackedInt(u80, buffer, bit_offset, endian)) },
-                128 => .{ .f128 = @as(f128, @bitCast(std.mem.readPackedInt(u128, buffer, bit_offset, endian))) },
+                128 => .{ .f128 = @bitCast(std.mem.readPackedInt(u128, buffer, bit_offset, endian)) },
                 else => unreachable,
             },
         } }))),
         .Vector => {
             const elem_ty = ty.childType(mod);
-            const elems = try arena.alloc(InternPool.Index, @as(usize, @intCast(ty.arrayLen(mod))));
+            const elems = try arena.alloc(InternPool.Index, @intCast(ty.arrayLen(mod)));
 
             var bits: u16 = 0;
-            const elem_bit_size = @as(u16, @intCast(elem_ty.bitSize(mod)));
+            const elem_bit_size: u16 = @intCast(elem_ty.bitSize(mod));
             for (elems, 0..) |_, i| {
                 // On big-endian systems, LLVM reverses the element order of vectors by default
                 const tgt_elem_i = if (endian == .big) elems.len - i - 1 else i;
@@ -909,7 +910,7 @@ fn bigIntToFloat(limbs: []const std.math.big.Limb, positive: bool) f128 {
     var i: usize = limbs.len;
     while (i != 0) {
         i -= 1;
-        const limb: f128 = @as(f128, @floatFromInt(limbs[i]));
+        const limb: f128 = @floatFromInt(limbs[i]);
         result = @mulAdd(f128, base, result, limb);
     }
     if (positive) {
@@ -934,7 +935,7 @@ pub fn ctz(val: Value, ty: Type, mod: *Module) u64 {
 pub fn popCount(val: Value, ty: Type, mod: *Module) u64 {
     var bigint_buf: BigIntSpace = undefined;
     const bigint = val.toBigInt(&bigint_buf, mod);
-    return @as(u64, @intCast(bigint.popCount(ty.intInfo(mod).bits)));
+    return @intCast(bigint.popCount(ty.intInfo(mod).bits));
 }
 
 pub fn bitReverse(val: Value, ty: Type, mod: *Module, arena: Allocator) !Value {
@@ -1191,7 +1192,7 @@ pub fn compareAllWithZeroAdvancedExtra(
             inline else => |x| if (std.math.isNan(x)) return op == .neq,
         },
         .aggregate => |aggregate| return switch (aggregate.storage) {
-            .bytes => |bytes| for (bytes) |byte| {
+            .bytes => |bytes| for (bytes.toSlice(lhs.typeOf(mod).arrayLenIncludingSentinel(mod), &mod.intern_pool)) |byte| {
                 if (!std.math.order(byte, 0).compare(op)) break false;
             } else true,
             .elems => |elems| for (elems) |elem| {
@@ -1279,7 +1280,7 @@ pub fn elemValue(val: Value, zcu: *Zcu, index: usize) Allocator.Error!Value {
             if (index < len) return Value.fromInterned(switch (aggregate.storage) {
                 .bytes => |bytes| try zcu.intern(.{ .int = .{
                     .ty = .u8_type,
-                    .storage = .{ .u64 = bytes[index] },
+                    .storage = .{ .u64 = bytes.at(index, ip) },
                 } }),
                 .elems => |elems| elems[index],
                 .repeated_elem => |elem| elem,
@@ -1318,28 +1319,37 @@ pub fn sliceArray(
     start: usize,
     end: usize,
 ) error{OutOfMemory}!Value {
-    // TODO: write something like getCoercedInts to avoid needing to dupe
     const mod = sema.mod;
-    const aggregate = mod.intern_pool.indexToKey(val.toIntern()).aggregate;
+    const ip = &mod.intern_pool;
-    return Value.fromInterned(try mod.intern(.{ .aggregate = .{
+    return Value.fromInterned(try mod.intern(.{
-        .ty = switch (mod.intern_pool.indexToKey(mod.intern_pool.typeOf(val.toIntern()))) {
+        .aggregate = .{
-            .array_type => |array_type| try mod.arrayType(.{
+            .ty = switch (mod.intern_pool.indexToKey(mod.intern_pool.typeOf(val.toIntern()))) {
-                .len = @as(u32, @intCast(end - start)),
+                .array_type => |array_type| try mod.arrayType(.{
-                .child = array_type.child,
+                    .len = @intCast(end - start),
-                .sentinel = if (end == array_type.len) array_type.sentinel else .none,
+                    .child = array_type.child,
-            }),
+                    .sentinel = if (end == array_type.len) array_type.sentinel else .none,
-            .vector_type => |vector_type| try mod.vectorType(.{
+                }),
-                .len = @as(u32, @intCast(end - start)),
+                .vector_type => |vector_type| try mod.vectorType(.{
-                .child = vector_type.child,
+                    .len = @intCast(end - start),
-            }),
+                    .child = vector_type.child,
-            else => unreachable,
+                }),
-        }.toIntern(),
+                else => unreachable,
-        .storage = switch (aggregate.storage) {
+            }.toIntern(),
-            .bytes => .{ .bytes = try sema.arena.dupe(u8, mod.intern_pool.indexToKey(val.toIntern()).aggregate.storage.bytes[start..end]) },
+            .storage = switch (ip.indexToKey(val.toIntern()).aggregate.storage) {
-            .elems => .{ .elems = try sema.arena.dupe(InternPool.Index, mod.intern_pool.indexToKey(val.toIntern()).aggregate.storage.elems[start..end]) },
+                .bytes => |bytes| storage: {
-            .repeated_elem => |elem| .{ .repeated_elem = elem },
+                    try ip.string_bytes.ensureUnusedCapacity(sema.gpa, end - start + 1);
+                    break :storage .{ .bytes = try ip.getOrPutString(
+                        sema.gpa,
+                        bytes.toSlice(end, ip)[start..],
+                        .maybe_embedded_nulls,
+                    ) };
+                },
+                // TODO: write something like getCoercedInts to avoid needing to dupe
+                .elems => |elems| .{ .elems = try sema.arena.dupe(InternPool.Index, elems[start..end]) },
+                .repeated_elem => |elem| .{ .repeated_elem = elem },
+            },
         },
-    } }));
+    }));
 }
 
 pub fn fieldValue(val: Value, mod: *Module, index: usize) !Value {
@@ -1350,7 +1360,7 @@ pub fn fieldValue(val: Value, mod: *Module, index: usize) !Value {
         .aggregate => |aggregate| Value.fromInterned(switch (aggregate.storage) {
             .bytes => |bytes| try mod.intern(.{ .int = .{
                 .ty = .u8_type,
-                .storage = .{ .u64 = bytes[index] },
+                .storage = .{ .u64 = bytes.at(index, &mod.intern_pool) },
             } }),
             .elems => |elems| elems[index],
             .repeated_elem => |elem| elem,
@@ -1461,7 +1471,7 @@ pub fn getErrorName(val: Value, mod: *const Module) InternPool.OptionalNullTermi
 
 pub fn getErrorInt(val: Value, mod: *const Module) Module.ErrorInt {
     return if (getErrorName(val, mod).unwrap()) |err_name|
-        @as(Module.ErrorInt, @intCast(mod.global_error_set.getIndex(err_name).?))
+        @intCast(mod.global_error_set.getIndex(err_name).?)
     else
         0;
 }
@@ -2413,14 +2423,14 @@ pub fn intTruncBitsAsValue(
         for (result_data, 0..) |*scalar, i| {
             const elem_val = try val.elemValue(mod, i);
             const bits_elem = try bits.elemValue(mod, i);
-            scalar.* = (try intTruncScalar(elem_val, scalar_ty, allocator, signedness, @as(u16, @intCast(bits_elem.toUnsignedInt(mod))), mod)).toIntern();
+            scalar.* = (try intTruncScalar(elem_val, scalar_ty, allocator, signedness, @intCast(bits_elem.toUnsignedInt(mod)), mod)).toIntern();
         }
         return Value.fromInterned((try mod.intern(.{ .aggregate = .{
             .ty = ty.toIntern(),
             .storage = .{ .elems = result_data },
         } })));
     }
-    return intTruncScalar(val, ty, allocator, signedness, @as(u16, @intCast(bits.toUnsignedInt(mod))), mod);
+    return intTruncScalar(val, ty, allocator, signedness, @intCast(bits.toUnsignedInt(mod)), mod);
 }
 
 pub fn intTruncScalar(
@@ -2468,7 +2478,7 @@ pub fn shlScalar(lhs: Value, rhs: Value, ty: Type, allocator: Allocator, mod: *M
     // resorting to BigInt first.
     var lhs_space: Value.BigIntSpace = undefined;
     const lhs_bigint = lhs.toBigInt(&lhs_space, mod);
-    const shift = @as(usize, @intCast(rhs.toUnsignedInt(mod)));
+    const shift: usize = @intCast(rhs.toUnsignedInt(mod));
     const limbs = try allocator.alloc(
         std.math.big.Limb,
         lhs_bigint.limbs.len + (shift / (@sizeOf(std.math.big.Limb) * 8)) + 1,
@@ -2530,7 +2540,7 @@ pub fn shlWithOverflowScalar(
     const info = ty.intInfo(mod);
     var lhs_space: Value.BigIntSpace = undefined;
     const lhs_bigint = lhs.toBigInt(&lhs_space, mod);
-    const shift = @as(usize, @intCast(rhs.toUnsignedInt(mod)));
+    const shift: usize = @intCast(rhs.toUnsignedInt(mod));
     const limbs = try allocator.alloc(
         std.math.big.Limb,
         lhs_bigint.limbs.len + (shift / (@sizeOf(std.math.big.Limb) * 8)) + 1,
@@ -2587,7 +2597,7 @@ pub fn shlSatScalar(
 
     var lhs_space: Value.BigIntSpace = undefined;
     const lhs_bigint = lhs.toBigInt(&lhs_space, mod);
-    const shift = @as(usize, @intCast(rhs.toUnsignedInt(mod)));
+    const shift: usize = @intCast(rhs.toUnsignedInt(mod));
     const limbs = try arena.alloc(
         std.math.big.Limb,
         std.math.big.int.calcTwosCompLimbCount(info.bits) + 1,
@@ -2659,7 +2669,7 @@ pub fn shrScalar(lhs: Value, rhs: Value, ty: Type, allocator: Allocator, mod: *M
     // resorting to BigInt first.
     var lhs_space: Value.BigIntSpace = undefined;
     const lhs_bigint = lhs.toBigInt(&lhs_space, mod);
-    const shift = @as(usize, @intCast(rhs.toUnsignedInt(mod)));
+    const shift: usize = @intCast(rhs.toUnsignedInt(mod));
 
     const result_limbs = lhs_bigint.limbs.len -| (shift / (@sizeOf(std.math.big.Limb) * 8));
     if (result_limbs == 0) {

src/arch/aarch64/CodeGen.zig

@@ -4345,8 +4345,8 @@ fn airCall(self: *Self, inst: Air.Inst.Index, modifier: std.builtin.CallModifier
                 .data = .{ .reg = .x30 },
             });
         } else if (func_value.getExternFunc(mod)) |extern_func| {
-            const decl_name = mod.intern_pool.stringToSlice(mod.declPtr(extern_func.decl).name);
+            const decl_name = mod.declPtr(extern_func.decl).name.toSlice(&mod.intern_pool);
-            const lib_name = mod.intern_pool.stringToSliceUnwrap(extern_func.lib_name);
+            const lib_name = extern_func.lib_name.toSlice(&mod.intern_pool);
             if (self.bin_file.cast(link.File.MachO)) |macho_file| {
                 _ = macho_file;
                 @panic("TODO airCall");

src/arch/wasm/CodeGen.zig

@@ -2199,9 +2199,9 @@ fn airCall(func: *CodeGen, inst: Air.Inst.Index, modifier: std.builtin.CallModif
             const atom = func.bin_file.getAtomPtr(atom_index);
             const type_index = try func.bin_file.storeDeclType(extern_func.decl, func_type);
             try func.bin_file.addOrUpdateImport(
-                mod.intern_pool.stringToSlice(ext_decl.name),
+                ext_decl.name.toSlice(&mod.intern_pool),
                 atom.sym_index,
-                mod.intern_pool.stringToSliceUnwrap(ext_decl.getOwnedExternFunc(mod).?.lib_name),
+                ext_decl.getOwnedExternFunc(mod).?.lib_name.toSlice(&mod.intern_pool),
                 type_index,
             );
             break :blk extern_func.decl;
@@ -7236,8 +7236,8 @@ fn getTagNameFunction(func: *CodeGen, enum_ty: Type) InnerError!u32 {
     defer arena_allocator.deinit();
     const arena = arena_allocator.allocator();
 
-    const fqn = ip.stringToSlice(try mod.declPtr(enum_decl_index).fullyQualifiedName(mod));
+    const fqn = try mod.declPtr(enum_decl_index).fullyQualifiedName(mod);
-    const func_name = try std.fmt.allocPrintZ(arena, "__zig_tag_name_{s}", .{fqn});
+    const func_name = try std.fmt.allocPrintZ(arena, "__zig_tag_name_{}", .{fqn.fmt(ip)});
 
     // check if we already generated code for this.
     if (func.bin_file.findGlobalSymbol(func_name)) |loc| {
@@ -7268,17 +7268,18 @@ fn getTagNameFunction(func: *CodeGen, enum_ty: Type) InnerError!u32 {
     // generate an if-else chain for each tag value as well as constant.
     const tag_names = enum_ty.enumFields(mod);
     for (0..tag_names.len) |tag_index| {
-        const tag_name = ip.stringToSlice(tag_names.get(ip)[tag_index]);
+        const tag_name = tag_names.get(ip)[tag_index];
+        const tag_name_len = tag_name.length(ip);
         // for each tag name, create an unnamed const,
         // and then get a pointer to its value.
         const name_ty = try mod.arrayType(.{
-            .len = tag_name.len,
+            .len = tag_name_len,
             .child = .u8_type,
             .sentinel = .zero_u8,
         });
         const name_val = try mod.intern(.{ .aggregate = .{
             .ty = name_ty.toIntern(),
-            .storage = .{ .bytes = tag_name },
+            .storage = .{ .bytes = tag_name.toString() },
         } });
         const tag_sym_index = try func.bin_file.lowerUnnamedConst(
             Value.fromInterned(name_val),
@@ -7338,7 +7339,7 @@ fn getTagNameFunction(func: *CodeGen, enum_ty: Type) InnerError!u32 {
 
             // store length
             try writer.writeByte(std.wasm.opcode(.i32_const));
-            try leb.writeULEB128(writer, @as(u32, @intCast(tag_name.len)));
+            try leb.writeULEB128(writer, @as(u32, @intCast(tag_name_len)));
             try writer.writeByte(std.wasm.opcode(.i32_store));
             try leb.writeULEB128(writer, encoded_alignment);
             try leb.writeULEB128(writer, @as(u32, 4));
@@ -7359,7 +7360,7 @@ fn getTagNameFunction(func: *CodeGen, enum_ty: Type) InnerError!u32 {
 
             // store length
             try writer.writeByte(std.wasm.opcode(.i64_const));
-            try leb.writeULEB128(writer, @as(u64, @intCast(tag_name.len)));
+            try leb.writeULEB128(writer, @as(u64, @intCast(tag_name_len)));
             try writer.writeByte(std.wasm.opcode(.i64_store));
             try leb.writeULEB128(writer, encoded_alignment);
             try leb.writeULEB128(writer, @as(u32, 8));

src/arch/x86_64/CodeGen.zig

@@ -2247,7 +2247,7 @@ fn genLazy(self: *Self, lazy_sym: link.File.LazySymbol) InnerError!void {
             var data_off: i32 = 0;
             const tag_names = enum_ty.enumFields(mod);
             for (exitlude_jump_relocs, 0..) |*exitlude_jump_reloc, tag_index| {
-                const tag_name_len = ip.stringToSlice(tag_names.get(ip)[tag_index]).len;
+                const tag_name_len = tag_names.get(ip)[tag_index].length(ip);
                 const tag_val = try mod.enumValueFieldIndex(enum_ty, @intCast(tag_index));
                 const tag_mcv = try self.genTypedValue(tag_val);
                 try self.genBinOpMir(.{ ._, .cmp }, enum_ty, enum_mcv, tag_mcv);
@@ -12314,8 +12314,8 @@ fn genCall(self: *Self, info: union(enum) {
                 },
                 .extern_func => |extern_func| {
                     const owner_decl = mod.declPtr(extern_func.decl);
-                    const lib_name = mod.intern_pool.stringToSliceUnwrap(extern_func.lib_name);
+                    const lib_name = extern_func.lib_name.toSlice(&mod.intern_pool);
-                    const decl_name = mod.intern_pool.stringToSlice(owner_decl.name);
+                    const decl_name = owner_decl.name.toSlice(&mod.intern_pool);
                     try self.genExternSymbolRef(.call, lib_name, decl_name);
                 },
                 else => return self.fail("TODO implement calling bitcasted functions", .{}),

src/codegen.zig

@@ -97,7 +97,7 @@ fn writeFloat(comptime F: type, f: F, target: Target, endian: std.builtin.Endian
     _ = target;
     const bits = @typeInfo(F).Float.bits;
     const Int = @Type(.{ .Int = .{ .signedness = .unsigned, .bits = bits } });
-    const int = @as(Int, @bitCast(f));
+    const int: Int = @bitCast(f);
     mem.writeInt(Int, code[0..@divExact(bits, 8)], int, endian);
 }
 
@@ -136,24 +136,24 @@ pub fn generateLazySymbol(
     if (lazy_sym.ty.isAnyError(zcu)) {
         alignment.* = .@"4";
         const err_names = zcu.global_error_set.keys();
-        mem.writeInt(u32, try code.addManyAsArray(4), @as(u32, @intCast(err_names.len)), endian);
+        mem.writeInt(u32, try code.addManyAsArray(4), @intCast(err_names.len), endian);
         var offset = code.items.len;
         try code.resize((1 + err_names.len + 1) * 4);
         for (err_names) |err_name_nts| {
-            const err_name = zcu.intern_pool.stringToSlice(err_name_nts);
+            const err_name = err_name_nts.toSlice(ip);
-            mem.writeInt(u32, code.items[offset..][0..4], @as(u32, @intCast(code.items.len)), endian);
+            mem.writeInt(u32, code.items[offset..][0..4], @intCast(code.items.len), endian);
             offset += 4;
             try code.ensureUnusedCapacity(err_name.len + 1);
             code.appendSliceAssumeCapacity(err_name);
             code.appendAssumeCapacity(0);
         }
-        mem.writeInt(u32, code.items[offset..][0..4], @as(u32, @intCast(code.items.len)), endian);
+        mem.writeInt(u32, code.items[offset..][0..4], @intCast(code.items.len), endian);
         return Result.ok;
     } else if (lazy_sym.ty.zigTypeTag(zcu) == .Enum) {
         alignment.* = .@"1";
         const tag_names = lazy_sym.ty.enumFields(zcu);
         for (0..tag_names.len) |tag_index| {
-            const tag_name = zcu.intern_pool.stringToSlice(tag_names.get(ip)[tag_index]);
+            const tag_name = tag_names.get(ip)[tag_index].toSlice(ip);
             try code.ensureUnusedCapacity(tag_name.len + 1);
             code.appendSliceAssumeCapacity(tag_name);
             code.appendAssumeCapacity(0);
@@ -241,13 +241,13 @@ pub fn generateSymbol(
         },
         .err => |err| {
             const int = try mod.getErrorValue(err.name);
-            try code.writer().writeInt(u16, @as(u16, @intCast(int)), endian);
+            try code.writer().writeInt(u16, @intCast(int), endian);
         },
         .error_union => |error_union| {
             const payload_ty = ty.errorUnionPayload(mod);
-            const err_val = switch (error_union.val) {
+            const err_val: u16 = switch (error_union.val) {
-                .err_name => |err_name| @as(u16, @intCast(try mod.getErrorValue(err_name))),
+                .err_name => |err_name| @intCast(try mod.getErrorValue(err_name)),
-                .payload => @as(u16, 0),
+                .payload => 0,
             };
 
             if (!payload_ty.hasRuntimeBitsIgnoreComptime(mod)) {
@@ -357,15 +357,13 @@ pub fn generateSymbol(
         },
         .aggregate => |aggregate| switch (ip.indexToKey(ty.toIntern())) {
             .array_type => |array_type| switch (aggregate.storage) {
-                .bytes => |bytes| try code.appendSlice(bytes),
+                .bytes => |bytes| try code.appendSlice(bytes.toSlice(array_type.lenIncludingSentinel(), ip)),
                 .elems, .repeated_elem => {
                     var index: u64 = 0;
-                    const len_including_sentinel =
+                    while (index < array_type.lenIncludingSentinel()) : (index += 1) {
-                        array_type.len + @intFromBool(array_type.sentinel != .none);
-                    while (index < len_including_sentinel) : (index += 1) {
                         switch (try generateSymbol(bin_file, src_loc, Value.fromInterned(switch (aggregate.storage) {
                             .bytes => unreachable,
-                            .elems => |elems| elems[@as(usize, @intCast(index))],
+                            .elems => |elems| elems[@intCast(index)],
                             .repeated_elem => |elem| if (index < array_type.len)
                                 elem
                             else
@@ -399,7 +397,7 @@ pub fn generateSymbol(
                         }) {
                             .bool_true => true,
                             .bool_false => false,
-                            else => |elem| switch (mod.intern_pool.indexToKey(elem)) {
+                            else => |elem| switch (ip.indexToKey(elem)) {
                                 .undef => continue,
                                 .int => |int| switch (int.storage) {
                                     .u64 => |x| switch (x) {
@@ -420,7 +418,7 @@ pub fn generateSymbol(
                     }
                 } else {
                     switch (aggregate.storage) {
-                        .bytes => |bytes| try code.appendSlice(bytes),
+                        .bytes => |bytes| try code.appendSlice(bytes.toSlice(vector_type.len, ip)),
                         .elems, .repeated_elem => {
                             var index: u64 = 0;
                             while (index < vector_type.len) : (index += 1) {
@@ -457,7 +455,7 @@ pub fn generateSymbol(
                     const field_val = switch (aggregate.storage) {
                         .bytes => |bytes| try ip.get(mod.gpa, .{ .int = .{
                             .ty = field_ty,
-                            .storage = .{ .u64 = bytes[index] },
+                            .storage = .{ .u64 = bytes.at(index, ip) },
                         } }),
                         .elems => |elems| elems[index],
                         .repeated_elem => |elem| elem,
@@ -493,7 +491,7 @@ pub fn generateSymbol(
                             const field_val = switch (aggregate.storage) {
                                 .bytes => |bytes| try ip.get(mod.gpa, .{ .int = .{
                                     .ty = field_ty,
-                                    .storage = .{ .u64 = bytes[index] },
+                                    .storage = .{ .u64 = bytes.at(index, ip) },
                                 } }),
                                 .elems => |elems| elems[index],
                                 .repeated_elem => |elem| elem,
@@ -513,7 +511,7 @@ pub fn generateSymbol(
                             } else {
                                 Value.fromInterned(field_val).writeToPackedMemory(Type.fromInterned(field_ty), mod, code.items[current_pos..], bits) catch unreachable;
                             }
-                            bits += @as(u16, @intCast(Type.fromInterned(field_ty).bitSize(mod)));
+                            bits += @intCast(Type.fromInterned(field_ty).bitSize(mod));
                         }
                     },
                     .auto, .@"extern" => {
@@ -529,7 +527,7 @@ pub fn generateSymbol(
                             const field_val = switch (ip.indexToKey(val.toIntern()).aggregate.storage) {
                                 .bytes => |bytes| try ip.get(mod.gpa, .{ .int = .{
                                     .ty = field_ty,
-                                    .storage = .{ .u64 = bytes[field_index] },
+                                    .storage = .{ .u64 = bytes.at(field_index, ip) },
                                 } }),
                                 .elems => |elems| elems[field_index],
                                 .repeated_elem => |elem| elem,
@@ -625,7 +623,8 @@ fn lowerParentPtr(
     reloc_info: RelocInfo,
 ) CodeGenError!Result {
     const mod = bin_file.comp.module.?;
-    const ptr = mod.intern_pool.indexToKey(parent_ptr).ptr;
+    const ip = &mod.intern_pool;
+    const ptr = ip.indexToKey(parent_ptr).ptr;
     return switch (ptr.addr) {
         .decl => |decl| try lowerDeclRef(bin_file, src_loc, decl, code, debug_output, reloc_info),
         .anon_decl => |ad| try lowerAnonDeclRef(bin_file, src_loc, ad, code, debug_output, reloc_info),
@@ -636,10 +635,10 @@ fn lowerParentPtr(
             eu_payload,
             code,
             debug_output,
-            reloc_info.offset(@as(u32, @intCast(errUnionPayloadOffset(
+            reloc_info.offset(@intCast(errUnionPayloadOffset(
-                Type.fromInterned(mod.intern_pool.typeOf(eu_payload)),
+                Type.fromInterned(ip.typeOf(eu_payload)),
                 mod,
-            )))),
+            ))),
         ),
         .opt_payload => |opt_payload| try lowerParentPtr(
             bin_file,
@@ -655,19 +654,19 @@ fn lowerParentPtr(
             elem.base,
             code,
             debug_output,
-            reloc_info.offset(@as(u32, @intCast(elem.index *
+            reloc_info.offset(@intCast(elem.index *
-                Type.fromInterned(mod.intern_pool.typeOf(elem.base)).elemType2(mod).abiSize(mod)))),
+                Type.fromInterned(ip.typeOf(elem.base)).elemType2(mod).abiSize(mod))),
         ),
         .field => |field| {
-            const base_ptr_ty = mod.intern_pool.typeOf(field.base);
+            const base_ptr_ty = ip.typeOf(field.base);
-            const base_ty = mod.intern_pool.indexToKey(base_ptr_ty).ptr_type.child;
+            const base_ty = ip.indexToKey(base_ptr_ty).ptr_type.child;
             return lowerParentPtr(
                 bin_file,
                 src_loc,
                 field.base,
                 code,
                 debug_output,
-                reloc_info.offset(switch (mod.intern_pool.indexToKey(base_ty)) {
+                reloc_info.offset(switch (ip.indexToKey(base_ty)) {
                     .ptr_type => |ptr_type| switch (ptr_type.flags.size) {
                         .One, .Many, .C => unreachable,
                         .Slice => switch (field.index) {
@@ -723,11 +722,12 @@ fn lowerAnonDeclRef(
 ) CodeGenError!Result {
     _ = debug_output;
     const zcu = lf.comp.module.?;
+    const ip = &zcu.intern_pool;
     const target = lf.comp.root_mod.resolved_target.result;
 
     const ptr_width_bytes = @divExact(target.ptrBitWidth(), 8);
     const decl_val = anon_decl.val;
-    const decl_ty = Type.fromInterned(zcu.intern_pool.typeOf(decl_val));
+    const decl_ty = Type.fromInterned(ip.typeOf(decl_val));
     log.debug("lowerAnonDecl: ty = {}", .{decl_ty.fmt(zcu)});
     const is_fn_body = decl_ty.zigTypeTag(zcu) == .Fn;
     if (!is_fn_body and !decl_ty.hasRuntimeBits(zcu)) {
@@ -735,7 +735,7 @@ fn lowerAnonDeclRef(
         return Result.ok;
     }
 
-    const decl_align = zcu.intern_pool.indexToKey(anon_decl.orig_ty).ptr_type.flags.alignment;
+    const decl_align = ip.indexToKey(anon_decl.orig_ty).ptr_type.flags.alignment;
     const res = try lf.lowerAnonDecl(decl_val, decl_align, src_loc);
     switch (res) {
         .ok => {},
@@ -787,8 +787,8 @@ fn lowerDeclRef(
     });
     const endian = target.cpu.arch.endian();
     switch (ptr_width) {
-        16 => mem.writeInt(u16, try code.addManyAsArray(2), @as(u16, @intCast(vaddr)), endian),
+        16 => mem.writeInt(u16, try code.addManyAsArray(2), @intCast(vaddr), endian),
-        32 => mem.writeInt(u32, try code.addManyAsArray(4), @as(u32, @intCast(vaddr)), endian),
+        32 => mem.writeInt(u32, try code.addManyAsArray(4), @intCast(vaddr), endian),
         64 => mem.writeInt(u64, try code.addManyAsArray(8), vaddr, endian),
         else => unreachable,
     }
@@ -859,6 +859,7 @@ fn genDeclRef(
     ptr_decl_index: InternPool.DeclIndex,
 ) CodeGenError!GenResult {
     const zcu = lf.comp.module.?;
+    const ip = &zcu.intern_pool;
     const ty = val.typeOf(zcu);
     log.debug("genDeclRef: val = {}", .{val.fmtValue(zcu)});
 
@@ -869,7 +870,7 @@ fn genDeclRef(
     const ptr_bits = target.ptrBitWidth();
     const ptr_bytes: u64 = @divExact(ptr_bits, 8);
 
-    const decl_index = switch (zcu.intern_pool.indexToKey(ptr_decl.val.toIntern())) {
+    const decl_index = switch (ip.indexToKey(ptr_decl.val.toIntern())) {
         .func => |func| func.owner_decl,
         .extern_func => |extern_func| extern_func.decl,
         else => ptr_decl_index,
@@ -909,12 +910,9 @@ fn genDeclRef(
 
     if (lf.cast(link.File.Elf)) |elf_file| {
         if (is_extern) {
-            const name = zcu.intern_pool.stringToSlice(decl.name);
+            const name = decl.name.toSlice(ip);
             // TODO audit this
-            const lib_name = if (decl.getOwnedVariable(zcu)) |ov|
+            const lib_name = if (decl.getOwnedVariable(zcu)) |ov| ov.lib_name.toSlice(ip) else null;
-                zcu.intern_pool.stringToSliceUnwrap(ov.lib_name)
-            else
-                null;
             const sym_index = try elf_file.getGlobalSymbol(name, lib_name);
             elf_file.symbol(elf_file.zigObjectPtr().?.symbol(sym_index)).flags.needs_got = true;
             return GenResult.mcv(.{ .load_symbol = sym_index });
@@ -927,11 +925,8 @@ fn genDeclRef(
         return GenResult.mcv(.{ .load_symbol = sym.esym_index });
     } else if (lf.cast(link.File.MachO)) |macho_file| {
         if (is_extern) {
-            const name = zcu.intern_pool.stringToSlice(decl.name);
+            const name = decl.name.toSlice(ip);
-            const lib_name = if (decl.getOwnedVariable(zcu)) |ov|
+            const lib_name = if (decl.getOwnedVariable(zcu)) |ov| ov.lib_name.toSlice(ip) else null;
-                zcu.intern_pool.stringToSliceUnwrap(ov.lib_name)
-            else
-                null;
             const sym_index = try macho_file.getGlobalSymbol(name, lib_name);
             macho_file.getSymbol(macho_file.getZigObject().?.symbols.items[sym_index]).flags.needs_got = true;
             return GenResult.mcv(.{ .load_symbol = sym_index });
@@ -944,12 +939,9 @@ fn genDeclRef(
         return GenResult.mcv(.{ .load_symbol = sym.nlist_idx });
     } else if (lf.cast(link.File.Coff)) |coff_file| {
         if (is_extern) {
-            const name = zcu.intern_pool.stringToSlice(decl.name);
+            const name = decl.name.toSlice(ip);
             // TODO audit this
-            const lib_name = if (decl.getOwnedVariable(zcu)) |ov|
+            const lib_name = if (decl.getOwnedVariable(zcu)) |ov| ov.lib_name.toSlice(ip) else null;
-                zcu.intern_pool.stringToSliceUnwrap(ov.lib_name)
-            else
-                null;
             const global_index = try coff_file.getGlobalSymbol(name, lib_name);
             try coff_file.need_got_table.put(gpa, global_index, {}); // needs GOT
             return GenResult.mcv(.{ .load_got = link.File.Coff.global_symbol_bit | global_index });
@@ -1012,6 +1004,7 @@ pub fn genTypedValue(
     owner_decl_index: InternPool.DeclIndex,
 ) CodeGenError!GenResult {
     const zcu = lf.comp.module.?;
+    const ip = &zcu.intern_pool;
     const ty = val.typeOf(zcu);
 
     log.debug("genTypedValue: val = {}", .{val.fmtValue(zcu)});
@@ -1024,7 +1017,7 @@ pub fn genTypedValue(
     const target = namespace.file_scope.mod.resolved_target.result;
     const ptr_bits = target.ptrBitWidth();
 
-    if (!ty.isSlice(zcu)) switch (zcu.intern_pool.indexToKey(val.toIntern())) {
+    if (!ty.isSlice(zcu)) switch (ip.indexToKey(val.toIntern())) {
         .ptr => |ptr| switch (ptr.addr) {
             .decl => |decl| return genDeclRef(lf, src_loc, val, decl),
             else => {},
@@ -1041,7 +1034,7 @@ pub fn genTypedValue(
                     return GenResult.mcv(.{ .immediate = 0 });
                 },
                 .none => {},
-                else => switch (zcu.intern_pool.indexToKey(val.toIntern())) {
+                else => switch (ip.indexToKey(val.toIntern())) {
                     .int => {
                         return GenResult.mcv(.{ .immediate = val.toUnsignedInt(zcu) });
                     },
@@ -1052,8 +1045,8 @@ pub fn genTypedValue(
         .Int => {
             const info = ty.intInfo(zcu);
             if (info.bits <= ptr_bits) {
-                const unsigned = switch (info.signedness) {
+                const unsigned: u64 = switch (info.signedness) {
-                    .signed => @as(u64, @bitCast(val.toSignedInt(zcu))),
+                    .signed => @bitCast(val.toSignedInt(zcu)),
                     .unsigned => val.toUnsignedInt(zcu),
                 };
                 return GenResult.mcv(.{ .immediate = unsigned });
@@ -1075,7 +1068,7 @@ pub fn genTypedValue(
             }
         },
         .Enum => {
-            const enum_tag = zcu.intern_pool.indexToKey(val.toIntern()).enum_tag;
+            const enum_tag = ip.indexToKey(val.toIntern()).enum_tag;
             return genTypedValue(
                 lf,
                 src_loc,
@@ -1084,7 +1077,7 @@ pub fn genTypedValue(
             );
         },
         .ErrorSet => {
-            const err_name = zcu.intern_pool.indexToKey(val.toIntern()).err.name;
+            const err_name = ip.indexToKey(val.toIntern()).err.name;
             const error_index = zcu.global_error_set.getIndex(err_name).?;
             return GenResult.mcv(.{ .immediate = error_index });
         },
@@ -1094,7 +1087,7 @@ pub fn genTypedValue(
             if (!payload_type.hasRuntimeBitsIgnoreComptime(zcu)) {
                 // We use the error type directly as the type.
                 const err_int_ty = try zcu.errorIntType();
-                switch (zcu.intern_pool.indexToKey(val.toIntern()).error_union.val) {
+                switch (ip.indexToKey(val.toIntern()).error_union.val) {
                     .err_name => |err_name| return genTypedValue(
                         lf,
                         src_loc,

src/codegen/c.zig

@@ -505,7 +505,7 @@ pub const Function = struct {
                     .never_inline,
                     => |owner_decl| try ctype_pool.fmt(gpa, "zig_{s}_{}__{d}", .{
                         @tagName(key),
-                        fmtIdent(zcu.intern_pool.stringToSlice(zcu.declPtr(owner_decl).name)),
+                        fmtIdent(zcu.declPtr(owner_decl).name.toSlice(&zcu.intern_pool)),
                         @intFromEnum(owner_decl),
                     }),
                 },
@@ -898,7 +898,7 @@ pub const DeclGen = struct {
                 },
             },
             .err => |err| try writer.print("zig_error_{}", .{
-                fmtIdent(ip.stringToSlice(err.name)),
+                fmtIdent(err.name.toSlice(ip)),
             }),
             .error_union => |error_union| {
                 const payload_ty = ty.errorUnionPayload(zcu);
@@ -1178,7 +1178,7 @@ pub const DeclGen = struct {
                             switch (ip.indexToKey(val.toIntern()).aggregate.storage) {
                                 .bytes => |bytes| try ip.get(zcu.gpa, .{ .int = .{
                                     .ty = field_ty.toIntern(),
-                                    .storage = .{ .u64 = bytes[field_index] },
+                                    .storage = .{ .u64 = bytes.at(field_index, ip) },
                                 } }),
                                 .elems => |elems| elems[field_index],
                                 .repeated_elem => |elem| elem,
@@ -1212,7 +1212,7 @@ pub const DeclGen = struct {
                                 const field_val = switch (ip.indexToKey(val.toIntern()).aggregate.storage) {
                                     .bytes => |bytes| try ip.get(zcu.gpa, .{ .int = .{
                                         .ty = field_ty.toIntern(),
-                                        .storage = .{ .u64 = bytes[field_index] },
+                                        .storage = .{ .u64 = bytes.at(field_index, ip) },
                                     } }),
                                     .elems => |elems| elems[field_index],
                                     .repeated_elem => |elem| elem,
@@ -1258,7 +1258,7 @@ pub const DeclGen = struct {
                                     const field_val = switch (ip.indexToKey(val.toIntern()).aggregate.storage) {
                                         .bytes => |bytes| try ip.get(zcu.gpa, .{ .int = .{
                                             .ty = field_ty.toIntern(),
-                                            .storage = .{ .u64 = bytes[field_index] },
+                                            .storage = .{ .u64 = bytes.at(field_index, ip) },
                                         } }),
                                         .elems => |elems| elems[field_index],
                                         .repeated_elem => |elem| elem,
@@ -1299,7 +1299,7 @@ pub const DeclGen = struct {
                                     const field_val = switch (ip.indexToKey(val.toIntern()).aggregate.storage) {
                                         .bytes => |bytes| try ip.get(zcu.gpa, .{ .int = .{
                                             .ty = field_ty.toIntern(),
-                                            .storage = .{ .u64 = bytes[field_index] },
+                                            .storage = .{ .u64 = bytes.at(field_index, ip) },
                                         } }),
                                         .elems => |elems| elems[field_index],
                                         .repeated_elem => |elem| elem,
@@ -1392,7 +1392,7 @@ pub const DeclGen = struct {
                         try writer.writeAll(" .payload = {");
                     }
                     if (field_ty.hasRuntimeBits(zcu)) {
-                        try writer.print(" .{ } = ", .{fmtIdent(ip.stringToSlice(field_name))});
+                        try writer.print(" .{ } = ", .{fmtIdent(field_name.toSlice(ip))});
                         try dg.renderValue(writer, Value.fromInterned(un.val), initializer_type);
                         try writer.writeByte(' ');
                     } else for (0..loaded_union.field_types.len) |this_field_index| {
@@ -1741,14 +1741,12 @@ pub const DeclGen = struct {
                 switch (name) {
                     .export_index => |export_index| mangled: {
                         const maybe_exports = zcu.decl_exports.get(fn_decl_index);
-                        const external_name = ip.stringToSlice(
+                        const external_name = (if (maybe_exports) |exports|
-                            if (maybe_exports) |exports|
+                            exports.items[export_index].opts.name
-                                exports.items[export_index].opts.name
+                        else if (fn_decl.isExtern(zcu))
-                            else if (fn_decl.isExtern(zcu))
+                            fn_decl.name
-                                fn_decl.name
+                        else
-                            else
+                            break :mangled).toSlice(ip);
-                                break :mangled,
-                        );
                         const is_mangled = isMangledIdent(external_name, true);
                         const is_export = export_index > 0;
                         if (is_mangled and is_export) {
@@ -1756,7 +1754,7 @@ pub const DeclGen = struct {
                                 fmtIdent(external_name),
                                 fmtStringLiteral(external_name, null),
                                 fmtStringLiteral(
-                                    ip.stringToSlice(maybe_exports.?.items[0].opts.name),
+                                    maybe_exports.?.items[0].opts.name.toSlice(ip),
                                     null,
                                 ),
                             });
@@ -1767,7 +1765,7 @@ pub const DeclGen = struct {
                         } else if (is_export) {
                             try w.print(" zig_export({s}, {s})", .{
                                 fmtStringLiteral(
-                                    ip.stringToSlice(maybe_exports.?.items[0].opts.name),
+                                    maybe_exports.?.items[0].opts.name.toSlice(ip),
                                     null,
                                 ),
                                 fmtStringLiteral(external_name, null),
@@ -2075,12 +2073,12 @@ pub const DeclGen = struct {
             .complete,
         );
         mangled: {
-            const external_name = zcu.intern_pool.stringToSlice(if (maybe_exports) |exports|
+            const external_name = (if (maybe_exports) |exports|
                 exports.items[0].opts.name
             else if (variable.is_extern)
                 decl.name
             else
-                break :mangled);
+                break :mangled).toSlice(&zcu.intern_pool);
             if (isMangledIdent(external_name, true)) {
                 try fwd.print(" zig_mangled_{s}({ }, {s})", .{
                     @tagName(fwd_kind),
@@ -2094,15 +2092,16 @@ pub const DeclGen = struct {
 
     fn renderDeclName(dg: *DeclGen, writer: anytype, decl_index: InternPool.DeclIndex, export_index: u32) !void {
         const zcu = dg.zcu;
+        const ip = &zcu.intern_pool;
         const decl = zcu.declPtr(decl_index);
 
         if (zcu.decl_exports.get(decl_index)) |exports| {
             try writer.print("{ }", .{
-                fmtIdent(zcu.intern_pool.stringToSlice(exports.items[export_index].opts.name)),
+                fmtIdent(exports.items[export_index].opts.name.toSlice(ip)),
             });
         } else if (decl.getExternDecl(zcu).unwrap()) |extern_decl_index| {
             try writer.print("{ }", .{
-                fmtIdent(zcu.intern_pool.stringToSlice(zcu.declPtr(extern_decl_index).name)),
+                fmtIdent(zcu.declPtr(extern_decl_index).name.toSlice(ip)),
             });
         } else {
             // MSVC has a limit of 4095 character token length limit, and fmtIdent can (worst case),
@@ -2226,7 +2225,7 @@ fn renderFwdDeclTypeName(
     switch (fwd_decl.name) {
         .anon => try w.print("anon__lazy_{d}", .{@intFromEnum(ctype.index)}),
         .owner_decl => |owner_decl| try w.print("{}__{d}", .{
-            fmtIdent(zcu.intern_pool.stringToSlice(zcu.declPtr(owner_decl).name)),
+            fmtIdent(zcu.declPtr(owner_decl).name.toSlice(&zcu.intern_pool)),
             @intFromEnum(owner_decl),
         }),
     }
@@ -2548,7 +2547,7 @@ pub fn genErrDecls(o: *Object) !void {
         try writer.writeAll("enum {\n");
         o.indent_writer.pushIndent();
         for (zcu.global_error_set.keys()[1..], 1..) |name_nts, value| {
-            const name = ip.stringToSlice(name_nts);
+            const name = name_nts.toSlice(ip);
             max_name_len = @max(name.len, max_name_len);
             const err_val = try zcu.intern(.{ .err = .{
                 .ty = .anyerror_type,
@@ -2566,19 +2565,19 @@ pub fn genErrDecls(o: *Object) !void {
     defer o.dg.gpa.free(name_buf);
 
     @memcpy(name_buf[0..name_prefix.len], name_prefix);
-    for (zcu.global_error_set.keys()) |name_ip| {
+    for (zcu.global_error_set.keys()) |name| {
-        const name = ip.stringToSlice(name_ip);
+        const name_slice = name.toSlice(ip);
-        @memcpy(name_buf[name_prefix.len..][0..name.len], name);
+        @memcpy(name_buf[name_prefix.len..][0..name_slice.len], name_slice);
-        const identifier = name_buf[0 .. name_prefix.len + name.len];
+        const identifier = name_buf[0 .. name_prefix.len + name_slice.len];
 
         const name_ty = try zcu.arrayType(.{
-            .len = name.len,
+            .len = name_slice.len,
             .child = .u8_type,
             .sentinel = .zero_u8,
         });
         const name_val = try zcu.intern(.{ .aggregate = .{
             .ty = name_ty.toIntern(),
-            .storage = .{ .bytes = name },
+            .storage = .{ .bytes = name.toString() },
         } });
 
         try writer.writeAll("static ");
@@ -2611,7 +2610,7 @@ pub fn genErrDecls(o: *Object) !void {
     );
     try writer.writeAll(" = {");
     for (zcu.global_error_set.keys(), 0..) |name_nts, value| {
-        const name = ip.stringToSlice(name_nts);
+        const name = name_nts.toSlice(ip);
         if (value != 0) try writer.writeByte(',');
         try writer.print("{{" ++ name_prefix ++ "{}, {}}}", .{
             fmtIdent(name),
@@ -2659,7 +2658,7 @@ fn genExports(o: *Object) !void {
     for (exports.items[1..]) |@"export"| {
         try fwd.writeAll("zig_extern ");
         if (@"export".opts.linkage == .weak) try fwd.writeAll("zig_weak_linkage ");
-        const export_name = ip.stringToSlice(@"export".opts.name);
+        const export_name = @"export".opts.name.toSlice(ip);
         try o.dg.renderTypeAndName(
             fwd,
             decl.typeOf(zcu),
@@ -2672,11 +2671,11 @@ fn genExports(o: *Object) !void {
             try fwd.print(" zig_mangled_export({ }, {s}, {s})", .{
                 fmtIdent(export_name),
                 fmtStringLiteral(export_name, null),
-                fmtStringLiteral(ip.stringToSlice(exports.items[0].opts.name), null),
+                fmtStringLiteral(exports.items[0].opts.name.toSlice(ip), null),
             });
         } else {
             try fwd.print(" zig_export({s}, {s})", .{
-                fmtStringLiteral(ip.stringToSlice(exports.items[0].opts.name), null),
+                fmtStringLiteral(exports.items[0].opts.name.toSlice(ip), null),
                 fmtStringLiteral(export_name, null),
             });
         }
@@ -2706,17 +2705,18 @@ pub fn genLazyFn(o: *Object, lazy_ctype_pool: *const CType.Pool, lazy_fn: LazyFn
             try w.writeAll(") {\n switch (tag) {\n");
             const tag_names = enum_ty.enumFields(zcu);
             for (0..tag_names.len) |tag_index| {
-                const tag_name = ip.stringToSlice(tag_names.get(ip)[tag_index]);
+                const tag_name = tag_names.get(ip)[tag_index];
+                const tag_name_len = tag_name.length(ip);
                 const tag_val = try zcu.enumValueFieldIndex(enum_ty, @intCast(tag_index));
 
                 const name_ty = try zcu.arrayType(.{
-                    .len = tag_name.len,
+                    .len = tag_name_len,
                     .child = .u8_type,
                     .sentinel = .zero_u8,
                 });
                 const name_val = try zcu.intern(.{ .aggregate = .{
                     .ty = name_ty.toIntern(),
-                    .storage = .{ .bytes = tag_name },
+                    .storage = .{ .bytes = tag_name.toString() },
                 } });
 
                 try w.print("  case {}: {{\n   static ", .{
@@ -2729,7 +2729,7 @@ pub fn genLazyFn(o: *Object, lazy_ctype_pool: *const CType.Pool, lazy_fn: LazyFn
                 try o.dg.renderType(w, name_slice_ty);
                 try w.print("){{{}, {}}};\n", .{
                     fmtIdent("name"),
-                    try o.dg.fmtIntLiteral(try zcu.intValue(Type.usize, tag_name.len), .Other),
+                    try o.dg.fmtIntLiteral(try zcu.intValue(Type.usize, tag_name_len), .Other),
                 });
 
                 try w.writeAll("  }\n");
@@ -2797,7 +2797,7 @@ pub fn genFunc(f: *Function) !void {
 
     try o.indent_writer.insertNewline();
     if (!is_global) try o.writer().writeAll("static ");
-    if (zcu.intern_pool.stringToSliceUnwrap(decl.@"linksection")) |s|
+    if (decl.@"linksection".toSlice(&zcu.intern_pool)) |s|
         try o.writer().print("zig_linksection_fn({s}) ", .{fmtStringLiteral(s, null)});
     try o.dg.renderFunctionSignature(o.writer(), decl_index, .complete, .{ .export_index = 0 });
     try o.writer().writeByte(' ');
@@ -2887,7 +2887,7 @@ pub fn genDecl(o: *Object) !void {
         if (!is_global) try w.writeAll("static ");
         if (variable.is_weak_linkage) try w.writeAll("zig_weak_linkage ");
         if (variable.is_threadlocal and !o.dg.mod.single_threaded) try w.writeAll("zig_threadlocal ");
-        if (zcu.intern_pool.stringToSliceUnwrap(decl.@"linksection")) |s|
+        if (decl.@"linksection".toSlice(&zcu.intern_pool)) |s|
             try w.print("zig_linksection({s}) ", .{fmtStringLiteral(s, null)});
         const decl_c_value = .{ .decl = decl_index };
         try o.dg.renderTypeAndName(w, decl_ty, decl_c_value, .{}, decl.alignment, .complete);
@@ -2920,7 +2920,7 @@ pub fn genDeclValue(
     switch (o.dg.pass) {
         .decl => |decl_index| {
             if (zcu.decl_exports.get(decl_index)) |exports| {
-                const export_name = zcu.intern_pool.stringToSlice(exports.items[0].opts.name);
+                const export_name = exports.items[0].opts.name.toSlice(&zcu.intern_pool);
                 if (isMangledIdent(export_name, true)) {
                     try fwd_decl_writer.print(" zig_mangled_final({ }, {s})", .{
                         fmtIdent(export_name), fmtStringLiteral(export_name, null),
@@ -2936,7 +2936,7 @@ pub fn genDeclValue(
 
     const w = o.writer();
     if (!is_global) try w.writeAll("static ");
-    if (zcu.intern_pool.stringToSliceUnwrap(@"linksection")) |s|
+    if (@"linksection".toSlice(&zcu.intern_pool)) |s|
         try w.print("zig_linksection({s}) ", .{fmtStringLiteral(s, null)});
     try o.dg.renderTypeAndName(w, ty, decl_c_value, Const, alignment, .complete);
     try w.writeAll(" = ");
@@ -5454,7 +5454,7 @@ fn fieldLocation(
                     .{ .byte_offset = loaded_struct.offsets.get(ip)[field_index] }
                 else
                     .{ .field = if (loaded_struct.fieldName(ip, field_index).unwrap()) |field_name|
-                        .{ .identifier = ip.stringToSlice(field_name) }
+                        .{ .identifier = field_name.toSlice(ip) }
                     else
                         .{ .field = field_index } },
                 .@"packed" => if (field_ptr_ty.ptrInfo(zcu).packed_offset.host_size == 0)
@@ -5470,7 +5470,7 @@ fn fieldLocation(
             .{ .byte_offset = container_ty.structFieldOffset(field_index, zcu) }
         else
             .{ .field = if (anon_struct_info.fieldName(ip, field_index).unwrap()) |field_name|
-                .{ .identifier = ip.stringToSlice(field_name) }
+                .{ .identifier = field_name.toSlice(ip) }
             else
                 .{ .field = field_index } },
         .union_type => {
@@ -5485,9 +5485,9 @@ fn fieldLocation(
                             .begin;
                     const field_name = loaded_union.loadTagType(ip).names.get(ip)[field_index];
                     return .{ .field = if (loaded_union.hasTag(ip))
-                        .{ .payload_identifier = ip.stringToSlice(field_name) }
+                        .{ .payload_identifier = field_name.toSlice(ip) }
                     else
-                        .{ .identifier = ip.stringToSlice(field_name) } };
+                        .{ .identifier = field_name.toSlice(ip) } };
                 },
                 .@"packed" => return .begin,
             }
@@ -5643,7 +5643,7 @@ fn airStructFieldVal(f: *Function, inst: Air.Inst.Index) !CValue {
             const loaded_struct = ip.loadStructType(struct_ty.toIntern());
             switch (loaded_struct.layout) {
                 .auto, .@"extern" => break :field_name if (loaded_struct.fieldName(ip, extra.field_index).unwrap()) |field_name|
-                    .{ .identifier = ip.stringToSlice(field_name) }
+                    .{ .identifier = field_name.toSlice(ip) }
                 else
                     .{ .field = extra.field_index },
                 .@"packed" => {
@@ -5701,7 +5701,7 @@ fn airStructFieldVal(f: *Function, inst: Air.Inst.Index) !CValue {
             }
         },
         .anon_struct_type => |anon_struct_info| if (anon_struct_info.fieldName(ip, extra.field_index).unwrap()) |field_name|
-            .{ .identifier = ip.stringToSlice(field_name) }
+            .{ .identifier = field_name.toSlice(ip) }
         else
             .{ .field = extra.field_index },
         .union_type => field_name: {
@@ -5710,9 +5710,9 @@ fn airStructFieldVal(f: *Function, inst: Air.Inst.Index) !CValue {
                 .auto, .@"extern" => {
                     const name = loaded_union.loadTagType(ip).names.get(ip)[extra.field_index];
                     break :field_name if (loaded_union.hasTag(ip))
-                        .{ .payload_identifier = ip.stringToSlice(name) }
+                        .{ .payload_identifier = name.toSlice(ip) }
                     else
-                        .{ .identifier = ip.stringToSlice(name) };
+                        .{ .identifier = name.toSlice(ip) };
                 },
                 .@"packed" => {
                     const operand_lval = if (struct_byval == .constant) blk: {
@@ -7062,7 +7062,7 @@ fn airAggregateInit(f: *Function, inst: Air.Inst.Index) !CValue {
 
                         const a = try Assignment.start(f, writer, field_ty);
                         try f.writeCValueMember(writer, local, if (loaded_struct.fieldName(ip, field_index).unwrap()) |field_name|
-                            .{ .identifier = ip.stringToSlice(field_name) }
+                            .{ .identifier = field_name.toSlice(ip) }
                         else
                             .{ .field = field_index });
                         try a.assign(f, writer);
@@ -7142,7 +7142,7 @@ fn airAggregateInit(f: *Function, inst: Air.Inst.Index) !CValue {
 
             const a = try Assignment.start(f, writer, field_ty);
             try f.writeCValueMember(writer, local, if (anon_struct_info.fieldName(ip, field_index).unwrap()) |field_name|
-                .{ .identifier = ip.stringToSlice(field_name) }
+                .{ .identifier = field_name.toSlice(ip) }
             else
                 .{ .field = field_index });
             try a.assign(f, writer);
@@ -7190,8 +7190,8 @@ fn airUnionInit(f: *Function, inst: Air.Inst.Index) !CValue {
             try writer.print("{}", .{try f.fmtIntLiteral(try tag_val.intFromEnum(tag_ty, zcu))});
             try a.end(f, writer);
         }
-        break :field .{ .payload_identifier = ip.stringToSlice(field_name) };
+        break :field .{ .payload_identifier = field_name.toSlice(ip) };
-    } else .{ .identifier = ip.stringToSlice(field_name) };
+    } else .{ .identifier = field_name.toSlice(ip) };
 
     const a = try Assignment.start(f, writer, payload_ty);
     try f.writeCValueMember(writer, local, field);

src/codegen/c/Type.zig

@@ -1465,7 +1465,7 @@ pub const Pool = struct {
                     },
                 },
                 .array_type => |array_info| {
-                    const len = array_info.len + @intFromBool(array_info.sentinel != .none);
+                    const len = array_info.lenIncludingSentinel();
                     if (len == 0) return .{ .index = .void };
                     const elem_type = Type.fromInterned(array_info.child);
                     const elem_ctype = try pool.fromType(
@@ -1479,7 +1479,7 @@ pub const Pool = struct {
                     if (elem_ctype.index == .void) return .{ .index = .void };
                     const array_ctype = try pool.getArray(allocator, .{
                         .elem_ctype = elem_ctype,
-                        .len = array_info.len + @intFromBool(array_info.sentinel != .none),
+                        .len = len,
                     });
                     if (!kind.isParameter()) return array_ctype;
                     var fields = [_]Info.Field{
@@ -1625,7 +1625,7 @@ pub const Pool = struct {
                                 if (field_ctype.index == .void) continue;
                                 const field_name = if (loaded_struct.fieldName(ip, field_index)
                                     .unwrap()) |field_name|
-                                    try pool.string(allocator, ip.stringToSlice(field_name))
+                                    try pool.string(allocator, field_name.toSlice(ip))
                                 else
                                     try pool.fmt(allocator, "f{d}", .{field_index});
                                 const field_alignas = AlignAs.fromAlignment(.{
@@ -1685,7 +1685,7 @@ pub const Pool = struct {
                         if (field_ctype.index == .void) continue;
                         const field_name = if (anon_struct_info.fieldName(ip, @intCast(field_index))
                             .unwrap()) |field_name|
-                            try pool.string(allocator, ip.stringToSlice(field_name))
+                            try pool.string(allocator, field_name.toSlice(ip))
                         else
                             try pool.fmt(allocator, "f{d}", .{field_index});
                         pool.addHashedExtraAssumeCapacityTo(scratch, &hasher, Field, .{
@@ -1766,7 +1766,7 @@ pub const Pool = struct {
                                 if (field_ctype.index == .void) continue;
                                 const field_name = try pool.string(
                                     allocator,
-                                    ip.stringToSlice(loaded_tag.names.get(ip)[field_index]),
+                                    loaded_tag.names.get(ip)[field_index].toSlice(ip),
                                 );
                                 const field_alignas = AlignAs.fromAlignment(.{
                                     .@"align" = loaded_union.fieldAlign(ip, @intCast(field_index)),

src/codegen/llvm.zig

@@ -1011,7 +1011,7 @@ pub const Object = struct {
 
         llvm_errors[0] = try o.builder.undefConst(llvm_slice_ty);
         for (llvm_errors[1..], error_name_list[1..]) |*llvm_error, name| {
-            const name_string = try o.builder.stringNull(mod.intern_pool.stringToSlice(name));
+            const name_string = try o.builder.stringNull(name.toSlice(&mod.intern_pool));
             const name_init = try o.builder.stringConst(name_string);
             const name_variable_index =
                 try o.builder.addVariable(.empty, name_init.typeOf(&o.builder), .default);
@@ -1086,7 +1086,7 @@ pub const Object = struct {
         for (object.extern_collisions.keys()) |decl_index| {
             const global = object.decl_map.get(decl_index) orelse continue;
             // Same logic as below but for externs instead of exports.
-            const decl_name = object.builder.strtabStringIfExists(mod.intern_pool.stringToSlice(mod.declPtr(decl_index).name)) orelse continue;
+            const decl_name = object.builder.strtabStringIfExists(mod.declPtr(decl_index).name.toSlice(&mod.intern_pool)) orelse continue;
             const other_global = object.builder.getGlobal(decl_name) orelse continue;
             if (other_global.toConst().getBase(&object.builder) ==
                 global.toConst().getBase(&object.builder)) continue;
@@ -1116,7 +1116,7 @@ pub const Object = struct {
         for (export_list) |exp| {
             // Detect if the LLVM global has already been created as an extern. In such
             // case, we need to replace all uses of it with this exported global.
-            const exp_name = object.builder.strtabStringIfExists(mod.intern_pool.stringToSlice(exp.opts.name)) orelse continue;
+            const exp_name = object.builder.strtabStringIfExists(exp.opts.name.toSlice(&mod.intern_pool)) orelse continue;
 
             const other_global = object.builder.getGlobal(exp_name) orelse continue;
             if (other_global.toConst().getBase(&object.builder) == global_base) continue;
@@ -1442,7 +1442,7 @@ pub const Object = struct {
             } }, &o.builder);
         }
 
-        if (ip.stringToSliceUnwrap(decl.@"linksection")) |section|
+        if (decl.@"linksection".toSlice(ip)) |section|
             function_index.setSection(try o.builder.string(section), &o.builder);
 
         var deinit_wip = true;
@@ -1662,7 +1662,7 @@ pub const Object = struct {
 
             const subprogram = try o.builder.debugSubprogram(
                 file,
-                try o.builder.metadataString(ip.stringToSlice(decl.name)),
+                try o.builder.metadataString(decl.name.toSlice(ip)),
                 try o.builder.metadataStringFromStrtabString(function_index.name(&o.builder)),
                 line_number,
                 line_number + func.lbrace_line,
@@ -1752,6 +1752,7 @@ pub const Object = struct {
             .value => |val| return updateExportedValue(self, mod, val, exports),
         };
         const gpa = mod.gpa;
+        const ip = &mod.intern_pool;
         // If the module does not already have the function, we ignore this function call
         // because we call `updateExports` at the end of `updateFunc` and `updateDecl`.
         const global_index = self.decl_map.get(decl_index) orelse return;
@@ -1759,17 +1760,14 @@ pub const Object = struct {
         const comp = mod.comp;
         if (decl.isExtern(mod)) {
             const decl_name = decl_name: {
-                const decl_name = mod.intern_pool.stringToSlice(decl.name);
-
                 if (mod.getTarget().isWasm() and decl.val.typeOf(mod).zigTypeTag(mod) == .Fn) {
-                    if (mod.intern_pool.stringToSliceUnwrap(decl.getOwnedExternFunc(mod).?.lib_name)) |lib_name| {
+                    if (decl.getOwnedExternFunc(mod).?.lib_name.toSlice(ip)) |lib_name| {
                         if (!std.mem.eql(u8, lib_name, "c")) {
-                            break :decl_name try self.builder.strtabStringFmt("{s}|{s}", .{ decl_name, lib_name });
+                            break :decl_name try self.builder.strtabStringFmt("{}|{s}", .{ decl.name.fmt(ip), lib_name });
                         }
                     }
                 }
-
+                break :decl_name try self.builder.strtabString(decl.name.toSlice(ip));
-                break :decl_name try self.builder.strtabString(decl_name);
             };
 
             if (self.builder.getGlobal(decl_name)) |other_global| {
@@ -1792,9 +1790,7 @@ pub const Object = struct {
                 if (decl_var.is_weak_linkage) global_index.setLinkage(.extern_weak, &self.builder);
             }
         } else if (exports.len != 0) {
-            const main_exp_name = try self.builder.strtabString(
+            const main_exp_name = try self.builder.strtabString(exports[0].opts.name.toSlice(ip));
-                mod.intern_pool.stringToSlice(exports[0].opts.name),
-            );
             try global_index.rename(main_exp_name, &self.builder);
 
             if (decl.val.getVariable(mod)) |decl_var| if (decl_var.is_threadlocal)
@@ -1803,9 +1799,7 @@ pub const Object = struct {
 
             return updateExportedGlobal(self, mod, global_index, exports);
         } else {
-            const fqn = try self.builder.strtabString(
+            const fqn = try self.builder.strtabString((try decl.fullyQualifiedName(mod)).toSlice(ip));
-                mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod)),
-            );
             try global_index.rename(fqn, &self.builder);
             global_index.setLinkage(.internal, &self.builder);
             if (comp.config.dll_export_fns)
@@ -1832,9 +1826,8 @@ pub const Object = struct {
         exports: []const *Module.Export,
     ) link.File.UpdateExportsError!void {
         const gpa = mod.gpa;
-        const main_exp_name = try o.builder.strtabString(
+        const ip = &mod.intern_pool;
-            mod.intern_pool.stringToSlice(exports[0].opts.name),
+        const main_exp_name = try o.builder.strtabString(exports[0].opts.name.toSlice(ip));
-        );
         const global_index = i: {
             const gop = try o.anon_decl_map.getOrPut(gpa, exported_value);
             if (gop.found_existing) {
@@ -1845,7 +1838,7 @@ pub const Object = struct {
             const llvm_addr_space = toLlvmAddressSpace(.generic, o.target);
             const variable_index = try o.builder.addVariable(
                 main_exp_name,
-                try o.lowerType(Type.fromInterned(mod.intern_pool.typeOf(exported_value))),
+                try o.lowerType(Type.fromInterned(ip.typeOf(exported_value))),
                 llvm_addr_space,
             );
             const global_index = variable_index.ptrConst(&o.builder).global;
@@ -1867,8 +1860,9 @@ pub const Object = struct {
         global_index: Builder.Global.Index,
         exports: []const *Module.Export,
     ) link.File.UpdateExportsError!void {
-        global_index.setUnnamedAddr(.default, &o.builder);
         const comp = mod.comp;
+        const ip = &mod.intern_pool;
+        global_index.setUnnamedAddr(.default, &o.builder);
         if (comp.config.dll_export_fns)
             global_index.setDllStorageClass(.dllexport, &o.builder);
         global_index.setLinkage(switch (exports[0].opts.linkage) {
@@ -1882,7 +1876,7 @@ pub const Object = struct {
             .hidden => .hidden,
             .protected => .protected,
         }, &o.builder);
-        if (mod.intern_pool.stringToSliceUnwrap(exports[0].opts.section)) |section|
+        if (exports[0].opts.section.toSlice(ip)) |section|
             switch (global_index.ptrConst(&o.builder).kind) {
                 .variable => |impl_index| impl_index.setSection(
                     try o.builder.string(section),
@@ -1900,7 +1894,7 @@ pub const Object = struct {
         // Until then we iterate over existing aliases and make them point
         // to the correct decl, or otherwise add a new alias. Old aliases are leaked.
         for (exports[1..]) |exp| {
-            const exp_name = try o.builder.strtabString(mod.intern_pool.stringToSlice(exp.opts.name));
+            const exp_name = try o.builder.strtabString(exp.opts.name.toSlice(ip));
             if (o.builder.getGlobal(exp_name)) |global| {
                 switch (global.ptrConst(&o.builder).kind) {
                     .alias => |alias| {
@@ -2013,7 +2007,7 @@ pub const Object = struct {
                         std.math.big.int.Mutable.init(&bigint_space.limbs, i).toConst();
 
                     enumerators[i] = try o.builder.debugEnumerator(
-                        try o.builder.metadataString(ip.stringToSlice(field_name_ip)),
+                        try o.builder.metadataString(field_name_ip.toSlice(ip)),
                         int_info.signedness == .unsigned,
                         int_info.bits,
                         bigint,
@@ -2473,7 +2467,7 @@ pub const Object = struct {
                             offset = field_offset + field_size;
 
                             const field_name = if (tuple.names.len != 0)
-                                ip.stringToSlice(tuple.names.get(ip)[i])
+                                tuple.names.get(ip)[i].toSlice(ip)
                             else
                                 try std.fmt.allocPrintZ(gpa, "{d}", .{i});
                             defer if (tuple.names.len == 0) gpa.free(field_name);
@@ -2557,10 +2551,10 @@ pub const Object = struct {
                     const field_offset = ty.structFieldOffset(field_index, mod);
 
                     const field_name = struct_type.fieldName(ip, field_index).unwrap() orelse
-                        try ip.getOrPutStringFmt(gpa, "{d}", .{field_index});
+                        try ip.getOrPutStringFmt(gpa, "{d}", .{field_index}, .no_embedded_nulls);
 
                     fields.appendAssumeCapacity(try o.builder.debugMemberType(
-                        try o.builder.metadataString(ip.stringToSlice(field_name)),
+                        try o.builder.metadataString(field_name.toSlice(ip)),
                         .none, // File
                         debug_fwd_ref,
                         0, // Line
@@ -2655,7 +2649,7 @@ pub const Object = struct {
 
                     const field_name = tag_type.names.get(ip)[field_index];
                     fields.appendAssumeCapacity(try o.builder.debugMemberType(
-                        try o.builder.metadataString(ip.stringToSlice(field_name)),
+                        try o.builder.metadataString(field_name.toSlice(ip)),
                         .none, // File
                         debug_union_fwd_ref,
                         0, // Line
@@ -2827,7 +2821,7 @@ pub const Object = struct {
         const mod = o.module;
         const decl = mod.declPtr(decl_index);
         return o.builder.debugStructType(
-            try o.builder.metadataString(mod.intern_pool.stringToSlice(decl.name)), // TODO use fully qualified name
+            try o.builder.metadataString(decl.name.toSlice(&mod.intern_pool)), // TODO use fully qualified name
             try o.getDebugFile(mod.namespacePtr(decl.src_namespace).file_scope),
             try o.namespaceToDebugScope(decl.src_namespace),
             decl.src_line + 1,
@@ -2844,11 +2838,11 @@ pub const Object = struct {
         const std_mod = mod.std_mod;
         const std_file = (mod.importPkg(std_mod) catch unreachable).file;
 
-        const builtin_str = try mod.intern_pool.getOrPutString(mod.gpa, "builtin");
+        const builtin_str = try mod.intern_pool.getOrPutString(mod.gpa, "builtin", .no_embedded_nulls);
         const std_namespace = mod.namespacePtr(mod.declPtr(std_file.root_decl.unwrap().?).src_namespace);
         const builtin_decl = std_namespace.decls.getKeyAdapted(builtin_str, Module.DeclAdapter{ .zcu = mod }).?;
 
-        const stack_trace_str = try mod.intern_pool.getOrPutString(mod.gpa, "StackTrace");
+        const stack_trace_str = try mod.intern_pool.getOrPutString(mod.gpa, "StackTrace", .no_embedded_nulls);
         // buffer is only used for int_type, `builtin` is a struct.
         const builtin_ty = mod.declPtr(builtin_decl).val.toType();
         const builtin_namespace = mod.namespacePtrUnwrap(builtin_ty.getNamespaceIndex(mod)).?;
@@ -2892,10 +2886,10 @@ pub const Object = struct {
         const is_extern = decl.isExtern(zcu);
         const function_index = try o.builder.addFunction(
             try o.lowerType(zig_fn_type),
-            try o.builder.strtabString(ip.stringToSlice(if (is_extern)
+            try o.builder.strtabString((if (is_extern)
                 decl.name
             else
-                try decl.fullyQualifiedName(zcu))),
+                try decl.fullyQualifiedName(zcu)).toSlice(ip)),
             toLlvmAddressSpace(decl.@"addrspace", target),
         );
         gop.value_ptr.* = function_index.ptrConst(&o.builder).global;
@@ -2910,9 +2904,9 @@ pub const Object = struct {
             if (target.isWasm()) {
                 try attributes.addFnAttr(.{ .string = .{
                     .kind = try o.builder.string("wasm-import-name"),
-                    .value = try o.builder.string(ip.stringToSlice(decl.name)),
+                    .value = try o.builder.string(decl.name.toSlice(ip)),
                 } }, &o.builder);
-                if (ip.stringToSliceUnwrap(decl.getOwnedExternFunc(zcu).?.lib_name)) |lib_name| {
+                if (decl.getOwnedExternFunc(zcu).?.lib_name.toSlice(ip)) |lib_name| {
                     if (!std.mem.eql(u8, lib_name, "c")) try attributes.addFnAttr(.{ .string = .{
                         .kind = try o.builder.string("wasm-import-module"),
                         .value = try o.builder.string(lib_name),
@@ -3108,9 +3102,10 @@ pub const Object = struct {
         const is_extern = decl.isExtern(mod);
 
         const variable_index = try o.builder.addVariable(
-            try o.builder.strtabString(mod.intern_pool.stringToSlice(
+            try o.builder.strtabString((if (is_extern)
-                if (is_extern) decl.name else try decl.fullyQualifiedName(mod),
+                decl.name
-            )),
+            else
+                try decl.fullyQualifiedName(mod)).toSlice(&mod.intern_pool)),
             try o.lowerType(decl.typeOf(mod)),
             toLlvmGlobalAddressSpace(decl.@"addrspace", mod.getTarget()),
         );
@@ -3258,7 +3253,7 @@ pub const Object = struct {
                     };
                 },
                 .array_type => |array_type| o.builder.arrayType(
-                    array_type.len + @intFromBool(array_type.sentinel != .none),
+                    array_type.lenIncludingSentinel(),
                     try o.lowerType(Type.fromInterned(array_type.child)),
                 ),
                 .vector_type => |vector_type| o.builder.vectorType(
@@ -3335,9 +3330,7 @@ pub const Object = struct {
                         return int_ty;
                     }
 
-                    const name = try o.builder.string(ip.stringToSlice(
+                    const fqn = try mod.declPtr(struct_type.decl.unwrap().?).fullyQualifiedName(mod);
-                        try mod.declPtr(struct_type.decl.unwrap().?).fullyQualifiedName(mod),
-                    ));
 
                     var llvm_field_types = std.ArrayListUnmanaged(Builder.Type){};
                     defer llvm_field_types.deinit(o.gpa);
@@ -3402,7 +3395,7 @@ pub const Object = struct {
                         );
                     }
 
-                    const ty = try o.builder.opaqueType(name);
+                    const ty = try o.builder.opaqueType(try o.builder.string(fqn.toSlice(ip)));
                     try o.type_map.put(o.gpa, t.toIntern(), ty);
 
                     o.builder.namedTypeSetBody(
@@ -3491,9 +3484,7 @@ pub const Object = struct {
                         return enum_tag_ty;
                     }
 
-                    const name = try o.builder.string(ip.stringToSlice(
+                    const fqn = try mod.declPtr(union_obj.decl).fullyQualifiedName(mod);
-                        try mod.declPtr(union_obj.decl).fullyQualifiedName(mod),
-                    ));
 
                     const aligned_field_ty = Type.fromInterned(union_obj.field_types.get(ip)[layout.most_aligned_field]);
                     const aligned_field_llvm_ty = try o.lowerType(aligned_field_ty);
@@ -3513,7 +3504,7 @@ pub const Object = struct {
                     };
 
                     if (layout.tag_size == 0) {
-                        const ty = try o.builder.opaqueType(name);
+                        const ty = try o.builder.opaqueType(try o.builder.string(fqn.toSlice(ip)));
                         try o.type_map.put(o.gpa, t.toIntern(), ty);
 
                         o.builder.namedTypeSetBody(
@@ -3541,7 +3532,7 @@ pub const Object = struct {
                         llvm_fields_len += 1;
                     }
 
-                    const ty = try o.builder.opaqueType(name);
+                    const ty = try o.builder.opaqueType(try o.builder.string(fqn.toSlice(ip)));
                     try o.type_map.put(o.gpa, t.toIntern(), ty);
 
                     o.builder.namedTypeSetBody(
@@ -3554,8 +3545,8 @@ pub const Object = struct {
                     const gop = try o.type_map.getOrPut(o.gpa, t.toIntern());
                     if (!gop.found_existing) {
                         const decl = mod.declPtr(ip.loadOpaqueType(t.toIntern()).decl);
-                        const name = try o.builder.string(ip.stringToSlice(try decl.fullyQualifiedName(mod)));
+                        const fqn = try decl.fullyQualifiedName(mod);
-                        gop.value_ptr.* = try o.builder.opaqueType(name);
+                        gop.value_ptr.* = try o.builder.opaqueType(try o.builder.string(fqn.toSlice(ip)));
                     }
                     return gop.value_ptr.*;
                 },
@@ -3859,7 +3850,9 @@ pub const Object = struct {
             },
             .aggregate => |aggregate| switch (ip.indexToKey(ty.toIntern())) {
                 .array_type => |array_type| switch (aggregate.storage) {
-                    .bytes => |bytes| try o.builder.stringConst(try o.builder.string(bytes)),
+                    .bytes => |bytes| try o.builder.stringConst(try o.builder.string(
+                        bytes.toSlice(array_type.lenIncludingSentinel(), ip),
+                    )),
                     .elems => |elems| {
                         const array_ty = try o.lowerType(ty);
                         const elem_ty = array_ty.childType(&o.builder);
@@ -3892,8 +3885,7 @@ pub const Object = struct {
                     },
                     .repeated_elem => |elem| {
                         const len: usize = @intCast(array_type.len);
-                        const len_including_sentinel: usize =
+                        const len_including_sentinel: usize = @intCast(array_type.lenIncludingSentinel());
-                            @intCast(len + @intFromBool(array_type.sentinel != .none));
                         const array_ty = try o.lowerType(ty);
                         const elem_ty = array_ty.childType(&o.builder);
 
@@ -3942,7 +3934,7 @@ pub const Object = struct {
                             defer allocator.free(vals);
 
                             switch (aggregate.storage) {
-                                .bytes => |bytes| for (vals, bytes) |*result_val, byte| {
+                                .bytes => |bytes| for (vals, bytes.toSlice(vector_type.len, ip)) |*result_val, byte| {
                                     result_val.* = try o.builder.intConst(.i8, byte);
                                 },
                                 .elems => |elems| for (vals, elems) |*result_val, elem| {
@@ -4633,7 +4625,7 @@ pub const Object = struct {
         defer wip_switch.finish(&wip);
 
         for (0..enum_type.names.len) |field_index| {
-            const name = try o.builder.stringNull(ip.stringToSlice(enum_type.names.get(ip)[field_index]));
+            const name = try o.builder.stringNull(enum_type.names.get(ip)[field_index].toSlice(ip));
             const name_init = try o.builder.stringConst(name);
             const name_variable_index =
                 try o.builder.addVariable(.empty, name_init.typeOf(&o.builder), .default);
@@ -4693,6 +4685,7 @@ pub const DeclGen = struct {
     fn genDecl(dg: *DeclGen) !void {
         const o = dg.object;
         const zcu = o.module;
+        const ip = &zcu.intern_pool;
         const decl = dg.decl;
         const decl_index = dg.decl_index;
         assert(decl.has_tv);
@@ -4705,7 +4698,7 @@ pub const DeclGen = struct {
                 decl.getAlignment(zcu).toLlvm(),
                 &o.builder,
             );
-            if (zcu.intern_pool.stringToSliceUnwrap(decl.@"linksection")) |section|
+            if (decl.@"linksection".toSlice(ip)) |section|
                 variable_index.setSection(try o.builder.string(section), &o.builder);
             assert(decl.has_tv);
             const init_val = if (decl.val.getVariable(zcu)) |decl_var| decl_var.init else init_val: {
@@ -4728,7 +4721,7 @@ pub const DeclGen = struct {
             const debug_file = try o.getDebugFile(namespace.file_scope);
 
             const debug_global_var = try o.builder.debugGlobalVar(
-                try o.builder.metadataString(zcu.intern_pool.stringToSlice(decl.name)), // Name
+                try o.builder.metadataString(decl.name.toSlice(ip)), // Name
                 try o.builder.metadataStringFromStrtabString(variable_index.name(&o.builder)), // Linkage name
                 debug_file, // File
                 debug_file, // Scope
@@ -5156,8 +5149,8 @@ pub const FuncGen = struct {
 
             self.scope = try o.builder.debugSubprogram(
                 self.file,
-                try o.builder.metadataString(zcu.intern_pool.stringToSlice(decl.name)),
+                try o.builder.metadataString(decl.name.toSlice(&zcu.intern_pool)),
-                try o.builder.metadataString(zcu.intern_pool.stringToSlice(fqn)),
+                try o.builder.metadataString(fqn.toSlice(&zcu.intern_pool)),
                 line_number,
                 line_number + func.lbrace_line,
                 try o.lowerDebugType(fn_ty),

src/codegen/spirv.zig

@@ -1028,39 +1028,30 @@ const DeclGen = struct {
                     inline .array_type, .vector_type => |array_type, tag| {
                         const elem_ty = Type.fromInterned(array_type.child);
 
-                        const constituents = try self.gpa.alloc(IdRef, @as(u32, @intCast(ty.arrayLenIncludingSentinel(mod))));
+                        const constituents = try self.gpa.alloc(IdRef, @intCast(ty.arrayLenIncludingSentinel(mod)));
                         defer self.gpa.free(constituents);
 
                         switch (aggregate.storage) {
                             .bytes => |bytes| {
                                 // TODO: This is really space inefficient, perhaps there is a better
                                 // way to do it?
-                                for (bytes, 0..) |byte, i| {
+                                for (constituents, bytes.toSlice(constituents.len, ip)) |*constituent, byte| {
-                                    constituents[i] = try self.constInt(elem_ty, byte, .indirect);
+                                    constituent.* = try self.constInt(elem_ty, byte, .indirect);
                                 }
                             },
                             .elems => |elems| {
-                                for (0..@as(usize, @intCast(array_type.len))) |i| {
+                                for (constituents, elems) |*constituent, elem| {
-                                    constituents[i] = try self.constant(elem_ty, Value.fromInterned(elems[i]), .indirect);
+                                    constituent.* = try self.constant(elem_ty, Value.fromInterned(elem), .indirect);
                                 }
                             },
                             .repeated_elem => |elem| {
-                                const val_id = try self.constant(elem_ty, Value.fromInterned(elem), .indirect);
+                                @memset(constituents, try self.constant(elem_ty, Value.fromInterned(elem), .indirect));
-                                for (0..@as(usize, @intCast(array_type.len))) |i| {
-                                    constituents[i] = val_id;
-                                }
                             },
                         }
 
                         switch (tag) {
-                            inline .array_type => {
+                            .array_type => return self.constructArray(ty, constituents),
-                                if (array_type.sentinel != .none) {
+                            .vector_type => return self.constructVector(ty, constituents),
-                                    const sentinel = Value.fromInterned(array_type.sentinel);
-                                    constituents[constituents.len - 1] = try self.constant(elem_ty, sentinel, .indirect);
-                                }
-                                return self.constructArray(ty, constituents);
-                            },
-                            inline .vector_type => return self.constructVector(ty, constituents),
                             else => unreachable,
                         }
                     },
@@ -1683,9 +1674,9 @@ const DeclGen = struct {
                     }
 
                     const field_name = struct_type.fieldName(ip, field_index).unwrap() orelse
-                        try ip.getOrPutStringFmt(mod.gpa, "{d}", .{field_index});
+                        try ip.getOrPutStringFmt(mod.gpa, "{d}", .{field_index}, .no_embedded_nulls);
                     try member_types.append(try self.resolveType(field_ty, .indirect));
-                    try member_names.append(ip.stringToSlice(field_name));
+                    try member_names.append(field_name.toSlice(ip));
                 }
 
                 const result_id = try self.spv.structType(member_types.items, member_names.items);
@@ -2123,12 +2114,12 @@ const DeclGen = struct {
                 // Append the actual code into the functions section.
                 try self.spv.addFunction(spv_decl_index, self.func);
 
-                const fqn = ip.stringToSlice(try decl.fullyQualifiedName(self.module));
+                const fqn = try decl.fullyQualifiedName(self.module);
-                try self.spv.debugName(result_id, fqn);
+                try self.spv.debugName(result_id, fqn.toSlice(ip));
 
                 // Temporarily generate a test kernel declaration if this is a test function.
                 if (self.module.test_functions.contains(self.decl_index)) {
-                    try self.generateTestEntryPoint(fqn, spv_decl_index);
+                    try self.generateTestEntryPoint(fqn.toSlice(ip), spv_decl_index);
                 }
             },
             .global => {
@@ -2152,8 +2143,8 @@ const DeclGen = struct {
                     .storage_class = final_storage_class,
                 });
 
-                const fqn = ip.stringToSlice(try decl.fullyQualifiedName(self.module));
+                const fqn = try decl.fullyQualifiedName(self.module);
-                try self.spv.debugName(result_id, fqn);
+                try self.spv.debugName(result_id, fqn.toSlice(ip));
                 try self.spv.declareDeclDeps(spv_decl_index, &.{});
             },
             .invocation_global => {
@@ -2197,8 +2188,8 @@ const DeclGen = struct {
                     try self.func.body.emit(self.spv.gpa, .OpFunctionEnd, {});
                     try self.spv.addFunction(spv_decl_index, self.func);
 
-                    const fqn = ip.stringToSlice(try decl.fullyQualifiedName(self.module));
+                    const fqn = try decl.fullyQualifiedName(self.module);
-                    try self.spv.debugNameFmt(initializer_id, "initializer of {s}", .{fqn});
+                    try self.spv.debugNameFmt(initializer_id, "initializer of {}", .{fqn.fmt(ip)});
 
                     try self.spv.sections.types_globals_constants.emit(self.spv.gpa, .OpExtInst, .{
                         .id_result_type = ptr_ty_id,

src/link/Coff.zig

@@ -1176,9 +1176,9 @@ pub fn lowerUnnamedConst(self: *Coff, val: Value, decl_index: InternPool.DeclInd
         gop.value_ptr.* = .{};
     }
     const unnamed_consts = gop.value_ptr;
-    const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const decl_name = try decl.fullyQualifiedName(mod);
     const index = unnamed_consts.items.len;
-    const sym_name = try std.fmt.allocPrint(gpa, "__unnamed_{s}_{d}", .{ decl_name, index });
+    const sym_name = try std.fmt.allocPrint(gpa, "__unnamed_{}_{d}", .{ decl_name.fmt(&mod.intern_pool), index });
     defer gpa.free(sym_name);
     const ty = val.typeOf(mod);
     const atom_index = switch (try self.lowerConst(sym_name, val, ty.abiAlignment(mod), self.rdata_section_index.?, decl.srcLoc(mod))) {
@@ -1257,8 +1257,8 @@ pub fn updateDecl(
     if (decl.isExtern(mod)) {
         // TODO make this part of getGlobalSymbol
         const variable = decl.getOwnedVariable(mod).?;
-        const name = mod.intern_pool.stringToSlice(decl.name);
+        const name = decl.name.toSlice(&mod.intern_pool);
-        const lib_name = mod.intern_pool.stringToSliceUnwrap(variable.lib_name);
+        const lib_name = variable.lib_name.toSlice(&mod.intern_pool);
         const global_index = try self.getGlobalSymbol(name, lib_name);
         try self.need_got_table.put(gpa, global_index, {});
         return;
@@ -1425,9 +1425,9 @@ fn updateDeclCode(self: *Coff, decl_index: InternPool.DeclIndex, code: []u8, com
     const mod = self.base.comp.module.?;
     const decl = mod.declPtr(decl_index);
 
-    const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const decl_name = try decl.fullyQualifiedName(mod);
 
-    log.debug("updateDeclCode {s}{*}", .{ decl_name, decl });
+    log.debug("updateDeclCode {}{*}", .{ decl_name.fmt(&mod.intern_pool), decl });
     const required_alignment: u32 = @intCast(decl.getAlignment(mod).toByteUnits() orelse 0);
 
     const decl_metadata = self.decls.get(decl_index).?;
@@ -1439,7 +1439,7 @@ fn updateDeclCode(self: *Coff, decl_index: InternPool.DeclIndex, code: []u8, com
 
     if (atom.size != 0) {
         const sym = atom.getSymbolPtr(self);
-        try self.setSymbolName(sym, decl_name);
+        try self.setSymbolName(sym, decl_name.toSlice(&mod.intern_pool));
         sym.section_number = @as(coff.SectionNumber, @enumFromInt(sect_index + 1));
         sym.type = .{ .complex_type = complex_type, .base_type = .NULL };
 
@@ -1447,7 +1447,7 @@ fn updateDeclCode(self: *Coff, decl_index: InternPool.DeclIndex, code: []u8, com
         const need_realloc = code.len > capacity or !mem.isAlignedGeneric(u64, sym.value, required_alignment);
         if (need_realloc) {
             const vaddr = try self.growAtom(atom_index, code_len, required_alignment);
-            log.debug("growing {s} from 0x{x} to 0x{x}", .{ decl_name, sym.value, vaddr });
+            log.debug("growing {} from 0x{x} to 0x{x}", .{ decl_name.fmt(&mod.intern_pool), sym.value, vaddr });
             log.debug("  (required alignment 0x{x}", .{required_alignment});
 
             if (vaddr != sym.value) {
@@ -1463,13 +1463,13 @@ fn updateDeclCode(self: *Coff, decl_index: InternPool.DeclIndex, code: []u8, com
         self.getAtomPtr(atom_index).size = code_len;
     } else {
         const sym = atom.getSymbolPtr(self);
-        try self.setSymbolName(sym, decl_name);
+        try self.setSymbolName(sym, decl_name.toSlice(&mod.intern_pool));
         sym.section_number = @as(coff.SectionNumber, @enumFromInt(sect_index + 1));
         sym.type = .{ .complex_type = complex_type, .base_type = .NULL };
 
         const vaddr = try self.allocateAtom(atom_index, code_len, required_alignment);
         errdefer self.freeAtom(atom_index);
-        log.debug("allocated atom for {s} at 0x{x}", .{ decl_name, vaddr });
+        log.debug("allocated atom for {} at 0x{x}", .{ decl_name.fmt(&mod.intern_pool), vaddr });
         self.getAtomPtr(atom_index).size = code_len;
         sym.value = vaddr;
 
@@ -1534,20 +1534,18 @@ pub fn updateExports(
                 else => std.builtin.CallingConvention.C,
             };
             const decl_cc = exported_decl.typeOf(mod).fnCallingConvention(mod);
-            if (decl_cc == .C and ip.stringEqlSlice(exp.opts.name, "main") and
+            if (decl_cc == .C and exp.opts.name.eqlSlice("main", ip) and comp.config.link_libc) {
-                comp.config.link_libc)
-            {
                 mod.stage1_flags.have_c_main = true;
             } else if (decl_cc == winapi_cc and target.os.tag == .windows) {
-                if (ip.stringEqlSlice(exp.opts.name, "WinMain")) {
+                if (exp.opts.name.eqlSlice("WinMain", ip)) {
                     mod.stage1_flags.have_winmain = true;
-                } else if (ip.stringEqlSlice(exp.opts.name, "wWinMain")) {
+                } else if (exp.opts.name.eqlSlice("wWinMain", ip)) {
                     mod.stage1_flags.have_wwinmain = true;
-                } else if (ip.stringEqlSlice(exp.opts.name, "WinMainCRTStartup")) {
+                } else if (exp.opts.name.eqlSlice("WinMainCRTStartup", ip)) {
                     mod.stage1_flags.have_winmain_crt_startup = true;
-                } else if (ip.stringEqlSlice(exp.opts.name, "wWinMainCRTStartup")) {
+                } else if (exp.opts.name.eqlSlice("wWinMainCRTStartup", ip)) {
                     mod.stage1_flags.have_wwinmain_crt_startup = true;
-                } else if (ip.stringEqlSlice(exp.opts.name, "DllMainCRTStartup")) {
+                } else if (exp.opts.name.eqlSlice("DllMainCRTStartup", ip)) {
                     mod.stage1_flags.have_dllmain_crt_startup = true;
                 }
             }
@@ -1585,7 +1583,7 @@ pub fn updateExports(
     for (exports) |exp| {
         log.debug("adding new export '{}'", .{exp.opts.name.fmt(&mod.intern_pool)});
 
-        if (mod.intern_pool.stringToSliceUnwrap(exp.opts.section)) |section_name| {
+        if (exp.opts.section.toSlice(&mod.intern_pool)) |section_name| {
             if (!mem.eql(u8, section_name, ".text")) {
                 try mod.failed_exports.putNoClobber(gpa, exp, try Module.ErrorMsg.create(
                     gpa,
@@ -1607,7 +1605,7 @@ pub fn updateExports(
             continue;
         }
 
-        const exp_name = mod.intern_pool.stringToSlice(exp.opts.name);
+        const exp_name = exp.opts.name.toSlice(&mod.intern_pool);
         const sym_index = metadata.getExport(self, exp_name) orelse blk: {
             const sym_index = if (self.getGlobalIndex(exp_name)) |global_index| ind: {
                 const global = self.globals.items[global_index];
@@ -1646,18 +1644,18 @@ pub fn updateExports(
 pub fn deleteDeclExport(
     self: *Coff,
     decl_index: InternPool.DeclIndex,
-    name_ip: InternPool.NullTerminatedString,
+    name: InternPool.NullTerminatedString,
 ) void {
     if (self.llvm_object) |_| return;
     const metadata = self.decls.getPtr(decl_index) orelse return;
     const mod = self.base.comp.module.?;
-    const name = mod.intern_pool.stringToSlice(name_ip);
+    const name_slice = name.toSlice(&mod.intern_pool);
-    const sym_index = metadata.getExportPtr(self, name) orelse return;
+    const sym_index = metadata.getExportPtr(self, name_slice) orelse return;
 
     const gpa = self.base.comp.gpa;
     const sym_loc = SymbolWithLoc{ .sym_index = sym_index.*, .file = null };
     const sym = self.getSymbolPtr(sym_loc);
-    log.debug("deleting export '{s}'", .{name});
+    log.debug("deleting export '{}'", .{name.fmt(&mod.intern_pool)});
     assert(sym.storage_class == .EXTERNAL and sym.section_number != .UNDEFINED);
     sym.* = .{
         .name = [_]u8{0} ** 8,
@@ -1669,7 +1667,7 @@ pub fn deleteDeclExport(
     };
     self.locals_free_list.append(gpa, sym_index.*) catch {};
 
-    if (self.resolver.fetchRemove(name)) |entry| {
+    if (self.resolver.fetchRemove(name_slice)) |entry| {
         defer gpa.free(entry.key);
         self.globals_free_list.append(gpa, entry.value) catch {};
         self.globals.items[entry.value] = .{

src/link/Dwarf.zig

@@ -339,15 +339,14 @@ pub const DeclState = struct {
                                     struct_type.field_names.get(ip),
                                     struct_type.field_types.get(ip),
                                     struct_type.offsets.get(ip),
-                                ) |field_name_ip, field_ty, field_off| {
+                                ) |field_name, field_ty, field_off| {
                                     if (!Type.fromInterned(field_ty).hasRuntimeBits(mod)) continue;
-                                    const field_name = ip.stringToSlice(field_name_ip);
+                                    const field_name_slice = field_name.toSlice(ip);
                                     // DW.AT.member
-                                    try dbg_info_buffer.ensureUnusedCapacity(field_name.len + 2);
+                                    try dbg_info_buffer.ensureUnusedCapacity(field_name_slice.len + 2);
                                     dbg_info_buffer.appendAssumeCapacity(@intFromEnum(AbbrevCode.struct_member));
                                     // DW.AT.name, DW.FORM.string
-                                    dbg_info_buffer.appendSliceAssumeCapacity(field_name);
+                                    dbg_info_buffer.appendSliceAssumeCapacity(field_name_slice[0 .. field_name_slice.len + 1]);
-                                    dbg_info_buffer.appendAssumeCapacity(0);
                                     // DW.AT.type, DW.FORM.ref4
                                     const index = dbg_info_buffer.items.len;
                                     try dbg_info_buffer.appendNTimes(0, 4);
@@ -374,14 +373,13 @@ pub const DeclState = struct {
                 try dbg_info_buffer.append(0);
 
                 const enum_type = ip.loadEnumType(ty.ip_index);
-                for (enum_type.names.get(ip), 0..) |field_name_index, field_i| {
+                for (enum_type.names.get(ip), 0..) |field_name, field_i| {
-                    const field_name = ip.stringToSlice(field_name_index);
+                    const field_name_slice = field_name.toSlice(ip);
                     // DW.AT.enumerator
-                    try dbg_info_buffer.ensureUnusedCapacity(field_name.len + 2 + @sizeOf(u64));
+                    try dbg_info_buffer.ensureUnusedCapacity(field_name_slice.len + 2 + @sizeOf(u64));
                     dbg_info_buffer.appendAssumeCapacity(@intFromEnum(AbbrevCode.enum_variant));
                     // DW.AT.name, DW.FORM.string
-                    dbg_info_buffer.appendSliceAssumeCapacity(field_name);
+                    dbg_info_buffer.appendSliceAssumeCapacity(field_name_slice[0 .. field_name_slice.len + 1]);
-                    dbg_info_buffer.appendAssumeCapacity(0);
                     // DW.AT.const_value, DW.FORM.data8
                     const value: u64 = value: {
                         if (enum_type.values.len == 0) break :value field_i; // auto-numbered
@@ -443,11 +441,11 @@ pub const DeclState = struct {
 
                 for (union_obj.field_types.get(ip), union_obj.loadTagType(ip).names.get(ip)) |field_ty, field_name| {
                     if (!Type.fromInterned(field_ty).hasRuntimeBits(mod)) continue;
+                    const field_name_slice = field_name.toSlice(ip);
                     // DW.AT.member
                     try dbg_info_buffer.append(@intFromEnum(AbbrevCode.struct_member));
                     // DW.AT.name, DW.FORM.string
-                    try dbg_info_buffer.appendSlice(ip.stringToSlice(field_name));
+                    try dbg_info_buffer.appendSlice(field_name_slice[0 .. field_name_slice.len + 1]);
-                    try dbg_info_buffer.append(0);
                     // DW.AT.type, DW.FORM.ref4
                     const index = dbg_info_buffer.items.len;
                     try dbg_info_buffer.appendNTimes(0, 4);
@@ -1155,8 +1153,8 @@ pub fn initDeclState(self: *Dwarf, mod: *Module, decl_index: InternPool.DeclInde
             dbg_line_buffer.appendAssumeCapacity(DW.LNS.copy);
 
             // .debug_info subprogram
-            const decl_name_slice = mod.intern_pool.stringToSlice(decl.name);
+            const decl_name_slice = decl.name.toSlice(&mod.intern_pool);
-            const decl_linkage_name_slice = mod.intern_pool.stringToSlice(decl_linkage_name);
+            const decl_linkage_name_slice = decl_linkage_name.toSlice(&mod.intern_pool);
             try dbg_info_buffer.ensureUnusedCapacity(1 + ptr_width_bytes + 4 + 4 +
                 (decl_name_slice.len + 1) + (decl_linkage_name_slice.len + 1));
 
@@ -2866,15 +2864,14 @@ fn addDbgInfoErrorSetNames(
     // DW.AT.const_value, DW.FORM.data8
     mem.writeInt(u64, dbg_info_buffer.addManyAsArrayAssumeCapacity(8), 0, target_endian);
 
-    for (error_names) |error_name_ip| {
+    for (error_names) |error_name| {
-        const int = try mod.getErrorValue(error_name_ip);
+        const int = try mod.getErrorValue(error_name);
-        const error_name = mod.intern_pool.stringToSlice(error_name_ip);
+        const error_name_slice = error_name.toSlice(&mod.intern_pool);
         // DW.AT.enumerator
-        try dbg_info_buffer.ensureUnusedCapacity(error_name.len + 2 + @sizeOf(u64));
+        try dbg_info_buffer.ensureUnusedCapacity(error_name_slice.len + 2 + @sizeOf(u64));
         dbg_info_buffer.appendAssumeCapacity(@intFromEnum(AbbrevCode.enum_variant));
         // DW.AT.name, DW.FORM.string
-        dbg_info_buffer.appendSliceAssumeCapacity(error_name);
+        dbg_info_buffer.appendSliceAssumeCapacity(error_name_slice[0 .. error_name_slice.len + 1]);
-        dbg_info_buffer.appendAssumeCapacity(0);
         // DW.AT.const_value, DW.FORM.data8
         mem.writeInt(u64, dbg_info_buffer.addManyAsArrayAssumeCapacity(8), int, target_endian);
     }

src/link/Elf/ZigObject.zig

@@ -902,9 +902,9 @@ fn updateDeclCode(
     const gpa = elf_file.base.comp.gpa;
     const mod = elf_file.base.comp.module.?;
     const decl = mod.declPtr(decl_index);
-    const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const decl_name = try decl.fullyQualifiedName(mod);
 
-    log.debug("updateDeclCode {s}{*}", .{ decl_name, decl });
+    log.debug("updateDeclCode {}{*}", .{ decl_name.fmt(&mod.intern_pool), decl });
 
     const required_alignment = decl.getAlignment(mod);
 
@@ -915,7 +915,7 @@ fn updateDeclCode(
     sym.output_section_index = shdr_index;
     atom_ptr.output_section_index = shdr_index;
 
-    sym.name_offset = try self.strtab.insert(gpa, decl_name);
+    sym.name_offset = try self.strtab.insert(gpa, decl_name.toSlice(&mod.intern_pool));
     atom_ptr.flags.alive = true;
     atom_ptr.name_offset = sym.name_offset;
     esym.st_name = sym.name_offset;
@@ -932,7 +932,7 @@ fn updateDeclCode(
         const need_realloc = code.len > capacity or !required_alignment.check(atom_ptr.value);
         if (need_realloc) {
             try atom_ptr.grow(elf_file);
-            log.debug("growing {s} from 0x{x} to 0x{x}", .{ decl_name, old_vaddr, atom_ptr.value });
+            log.debug("growing {} from 0x{x} to 0x{x}", .{ decl_name.fmt(&mod.intern_pool), old_vaddr, atom_ptr.value });
             if (old_vaddr != atom_ptr.value) {
                 sym.value = 0;
                 esym.st_value = 0;
@@ -1000,9 +1000,9 @@ fn updateTlv(
     const gpa = elf_file.base.comp.gpa;
     const mod = elf_file.base.comp.module.?;
     const decl = mod.declPtr(decl_index);
-    const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const decl_name = try decl.fullyQualifiedName(mod);
 
-    log.debug("updateTlv {s} ({*})", .{ decl_name, decl });
+    log.debug("updateTlv {} ({*})", .{ decl_name.fmt(&mod.intern_pool), decl });
 
     const required_alignment = decl.getAlignment(mod);
 
@@ -1014,7 +1014,7 @@ fn updateTlv(
     sym.output_section_index = shndx;
     atom_ptr.output_section_index = shndx;
 
-    sym.name_offset = try self.strtab.insert(gpa, decl_name);
+    sym.name_offset = try self.strtab.insert(gpa, decl_name.toSlice(&mod.intern_pool));
     atom_ptr.flags.alive = true;
     atom_ptr.name_offset = sym.name_offset;
     esym.st_value = 0;
@@ -1136,8 +1136,8 @@ pub fn updateDecl(
     if (decl.isExtern(mod)) {
         // Extern variable gets a .got entry only.
         const variable = decl.getOwnedVariable(mod).?;
-        const name = mod.intern_pool.stringToSlice(decl.name);
+        const name = decl.name.toSlice(&mod.intern_pool);
-        const lib_name = mod.intern_pool.stringToSliceUnwrap(variable.lib_name);
+        const lib_name = variable.lib_name.toSlice(&mod.intern_pool);
         const esym_index = try self.getGlobalSymbol(elf_file, name, lib_name);
         elf_file.symbol(self.symbol(esym_index)).flags.needs_got = true;
         return;
@@ -1293,9 +1293,9 @@ pub fn lowerUnnamedConst(
     }
     const unnamed_consts = gop.value_ptr;
     const decl = mod.declPtr(decl_index);
-    const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const decl_name = try decl.fullyQualifiedName(mod);
     const index = unnamed_consts.items.len;
-    const name = try std.fmt.allocPrint(gpa, "__unnamed_{s}_{d}", .{ decl_name, index });
+    const name = try std.fmt.allocPrint(gpa, "__unnamed_{}_{d}", .{ decl_name.fmt(&mod.intern_pool), index });
     defer gpa.free(name);
     const ty = val.typeOf(mod);
     const sym_index = switch (try self.lowerConst(
@@ -1418,7 +1418,7 @@ pub fn updateExports(
 
     for (exports) |exp| {
         if (exp.opts.section.unwrap()) |section_name| {
-            if (!mod.intern_pool.stringEqlSlice(section_name, ".text")) {
+            if (!section_name.eqlSlice(".text", &mod.intern_pool)) {
                 try mod.failed_exports.ensureUnusedCapacity(mod.gpa, 1);
                 mod.failed_exports.putAssumeCapacityNoClobber(exp, try Module.ErrorMsg.create(
                     gpa,
@@ -1445,7 +1445,7 @@ pub fn updateExports(
             },
         };
         const stt_bits: u8 = @as(u4, @truncate(esym.st_info));
-        const exp_name = mod.intern_pool.stringToSlice(exp.opts.name);
+        const exp_name = exp.opts.name.toSlice(&mod.intern_pool);
         const name_off = try self.strtab.insert(gpa, exp_name);
         const global_esym_index = if (metadata.@"export"(self, exp_name)) |exp_index|
             exp_index.*
@@ -1476,9 +1476,9 @@ pub fn updateDeclLineNumber(
     defer tracy.end();
 
     const decl = mod.declPtr(decl_index);
-    const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const decl_name = try decl.fullyQualifiedName(mod);
 
-    log.debug("updateDeclLineNumber {s}{*}", .{ decl_name, decl });
+    log.debug("updateDeclLineNumber {}{*}", .{ decl_name.fmt(&mod.intern_pool), decl });
 
     if (self.dwarf) |*dw| {
         try dw.updateDeclLineNumber(mod, decl_index);
@@ -1493,7 +1493,7 @@ pub fn deleteDeclExport(
 ) void {
     const metadata = self.decls.getPtr(decl_index) orelse return;
     const mod = elf_file.base.comp.module.?;
-    const exp_name = mod.intern_pool.stringToSlice(name);
+    const exp_name = name.toSlice(&mod.intern_pool);
     const esym_index = metadata.@"export"(self, exp_name) orelse return;
     log.debug("deleting export '{s}'", .{exp_name});
     const esym = &self.global_esyms.items(.elf_sym)[esym_index.*];

src/link/MachO/ZigObject.zig

@@ -716,8 +716,8 @@ pub fn updateDecl(
     if (decl.isExtern(mod)) {
         // Extern variable gets a __got entry only
         const variable = decl.getOwnedVariable(mod).?;
-        const name = mod.intern_pool.stringToSlice(decl.name);
+        const name = decl.name.toSlice(&mod.intern_pool);
-        const lib_name = mod.intern_pool.stringToSliceUnwrap(variable.lib_name);
+        const lib_name = variable.lib_name.toSlice(&mod.intern_pool);
         const index = try self.getGlobalSymbol(macho_file, name, lib_name);
         const actual_index = self.symbols.items[index];
         macho_file.getSymbol(actual_index).flags.needs_got = true;
@@ -786,9 +786,9 @@ fn updateDeclCode(
     const gpa = macho_file.base.comp.gpa;
     const mod = macho_file.base.comp.module.?;
     const decl = mod.declPtr(decl_index);
-    const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const decl_name = try decl.fullyQualifiedName(mod);
 
-    log.debug("updateDeclCode {s}{*}", .{ decl_name, decl });
+    log.debug("updateDeclCode {}{*}", .{ decl_name.fmt(&mod.intern_pool), decl });
 
     const required_alignment = decl.getAlignment(mod);
 
@@ -800,7 +800,7 @@ fn updateDeclCode(
     sym.out_n_sect = sect_index;
     atom.out_n_sect = sect_index;
 
-    sym.name = try self.strtab.insert(gpa, decl_name);
+    sym.name = try self.strtab.insert(gpa, decl_name.toSlice(&mod.intern_pool));
     atom.flags.alive = true;
     atom.name = sym.name;
     nlist.n_strx = sym.name;
@@ -819,7 +819,7 @@ fn updateDeclCode(
 
         if (need_realloc) {
             try atom.grow(macho_file);
-            log.debug("growing {s} from 0x{x} to 0x{x}", .{ decl_name, old_vaddr, atom.value });
+            log.debug("growing {} from 0x{x} to 0x{x}", .{ decl_name.fmt(&mod.intern_pool), old_vaddr, atom.value });
             if (old_vaddr != atom.value) {
                 sym.value = 0;
                 nlist.n_value = 0;
@@ -870,23 +870,24 @@ fn updateTlv(
 ) !void {
     const mod = macho_file.base.comp.module.?;
     const decl = mod.declPtr(decl_index);
-    const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const decl_name = try decl.fullyQualifiedName(mod);
 
-    log.debug("updateTlv {s} ({*})", .{ decl_name, decl });
+    log.debug("updateTlv {} ({*})", .{ decl_name.fmt(&mod.intern_pool), decl });
 
+    const decl_name_slice = decl_name.toSlice(&mod.intern_pool);
     const required_alignment = decl.getAlignment(mod);
 
     // 1. Lower TLV initializer
     const init_sym_index = try self.createTlvInitializer(
         macho_file,
-        decl_name,
+        decl_name_slice,
         required_alignment,
         sect_index,
         code,
     );
 
     // 2. Create TLV descriptor
-    try self.createTlvDescriptor(macho_file, sym_index, init_sym_index, decl_name);
+    try self.createTlvDescriptor(macho_file, sym_index, init_sym_index, decl_name_slice);
 }
 
 fn createTlvInitializer(
@@ -1073,9 +1074,9 @@ pub fn lowerUnnamedConst(
     }
     const unnamed_consts = gop.value_ptr;
     const decl = mod.declPtr(decl_index);
-    const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const decl_name = try decl.fullyQualifiedName(mod);
     const index = unnamed_consts.items.len;
-    const name = try std.fmt.allocPrint(gpa, "__unnamed_{s}_{d}", .{ decl_name, index });
+    const name = try std.fmt.allocPrint(gpa, "__unnamed_{}_{d}", .{ decl_name.fmt(&mod.intern_pool), index });
     defer gpa.free(name);
     const sym_index = switch (try self.lowerConst(
         macho_file,
@@ -1199,7 +1200,7 @@ pub fn updateExports(
 
     for (exports) |exp| {
         if (exp.opts.section.unwrap()) |section_name| {
-            if (!mod.intern_pool.stringEqlSlice(section_name, "__text")) {
+            if (!section_name.eqlSlice("__text", &mod.intern_pool)) {
                 try mod.failed_exports.ensureUnusedCapacity(mod.gpa, 1);
                 mod.failed_exports.putAssumeCapacityNoClobber(exp, try Module.ErrorMsg.create(
                     gpa,
@@ -1220,7 +1221,7 @@ pub fn updateExports(
             continue;
         }
 
-        const exp_name = mod.intern_pool.stringToSlice(exp.opts.name);
+        const exp_name = exp.opts.name.toSlice(&mod.intern_pool);
         const global_nlist_index = if (metadata.@"export"(self, exp_name)) |exp_index|
             exp_index.*
         else blk: {
@@ -1349,13 +1350,12 @@ pub fn deleteDeclExport(
     decl_index: InternPool.DeclIndex,
     name: InternPool.NullTerminatedString,
 ) void {
-    const metadata = self.decls.getPtr(decl_index) orelse return;
-
     const mod = macho_file.base.comp.module.?;
-    const exp_name = mod.intern_pool.stringToSlice(name);
-    const nlist_index = metadata.@"export"(self, exp_name) orelse return;
 
-    log.debug("deleting export '{s}'", .{exp_name});
+    const metadata = self.decls.getPtr(decl_index) orelse return;
+    const nlist_index = metadata.@"export"(self, name.toSlice(&mod.intern_pool)) orelse return;
+
+    log.debug("deleting export '{}'", .{name.fmt(&mod.intern_pool)});
 
     const nlist = &self.symtab.items(.nlist)[nlist_index.*];
     self.symtab.items(.size)[nlist_index.*] = 0;

src/link/Plan9.zig

@@ -477,11 +477,11 @@ pub fn lowerUnnamedConst(self: *Plan9, val: Value, decl_index: InternPool.DeclIn
     }
     const unnamed_consts = gop.value_ptr;
 
-    const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const decl_name = try decl.fullyQualifiedName(mod);
 
     const index = unnamed_consts.items.len;
     // name is freed when the unnamed const is freed
-    const name = try std.fmt.allocPrint(gpa, "__unnamed_{s}_{d}", .{ decl_name, index });
+    const name = try std.fmt.allocPrint(gpa, "__unnamed_{}_{d}", .{ decl_name.fmt(&mod.intern_pool), index });
 
     const sym_index = try self.allocateSymbolIndex();
     const new_atom_idx = try self.createAtom();
@@ -529,7 +529,7 @@ pub fn updateDecl(self: *Plan9, mod: *Module, decl_index: InternPool.DeclIndex)
     const decl = mod.declPtr(decl_index);
 
     if (decl.isExtern(mod)) {
-        log.debug("found extern decl: {s}", .{mod.intern_pool.stringToSlice(decl.name)});
+        log.debug("found extern decl: {}", .{decl.name.fmt(&mod.intern_pool)});
         return;
     }
     const atom_idx = try self.seeDecl(decl_index);
@@ -573,7 +573,7 @@ fn updateFinish(self: *Plan9, decl_index: InternPool.DeclIndex) !void {
     const sym: aout.Sym = .{
         .value = undefined, // the value of stuff gets filled in in flushModule
         .type = atom.type,
-        .name = try gpa.dupe(u8, mod.intern_pool.stringToSlice(decl.name)),
+        .name = try gpa.dupe(u8, decl.name.toSlice(&mod.intern_pool)),
     };
 
     if (atom.sym_index) |s| {
@@ -1013,10 +1013,12 @@ fn addDeclExports(
     const atom = self.getAtom(metadata.index);
 
     for (exports) |exp| {
-        const exp_name = mod.intern_pool.stringToSlice(exp.opts.name);
+        const exp_name = exp.opts.name.toSlice(&mod.intern_pool);
         // plan9 does not support custom sections
         if (exp.opts.section.unwrap()) |section_name| {
-            if (!mod.intern_pool.stringEqlSlice(section_name, ".text") and !mod.intern_pool.stringEqlSlice(section_name, ".data")) {
+            if (!section_name.eqlSlice(".text", &mod.intern_pool) and
+                !section_name.eqlSlice(".data", &mod.intern_pool))
+            {
                 try mod.failed_exports.put(mod.gpa, exp, try Module.ErrorMsg.create(
                     gpa,
                     mod.declPtr(decl_index).srcLoc(mod),
@@ -1129,19 +1131,21 @@ pub fn seeDecl(self: *Plan9, decl_index: InternPool.DeclIndex) !Atom.Index {
     // handle externs here because they might not get updateDecl called on them
     const mod = self.base.comp.module.?;
     const decl = mod.declPtr(decl_index);
-    const name = mod.intern_pool.stringToSlice(decl.name);
     if (decl.isExtern(mod)) {
         // this is a "phantom atom" - it is never actually written to disk, just convenient for us to store stuff about externs
-        if (std.mem.eql(u8, name, "etext")) {
+        if (decl.name.eqlSlice("etext", &mod.intern_pool)) {
             self.etext_edata_end_atom_indices[0] = atom_idx;
-        } else if (std.mem.eql(u8, name, "edata")) {
+        } else if (decl.name.eqlSlice("edata", &mod.intern_pool)) {
             self.etext_edata_end_atom_indices[1] = atom_idx;
-        } else if (std.mem.eql(u8, name, "end")) {
+        } else if (decl.name.eqlSlice("end", &mod.intern_pool)) {
             self.etext_edata_end_atom_indices[2] = atom_idx;
         }
         try self.updateFinish(decl_index);
-        log.debug("seeDecl(extern) for {s} (got_addr=0x{x})", .{ name, self.getAtom(atom_idx).getOffsetTableAddress(self) });
+        log.debug("seeDecl(extern) for {} (got_addr=0x{x})", .{
-    } else log.debug("seeDecl for {s}", .{name});
+            decl.name.fmt(&mod.intern_pool),
+            self.getAtom(atom_idx).getOffsetTableAddress(self),
+        });
+    } else log.debug("seeDecl for {}", .{decl.name.fmt(&mod.intern_pool)});
     return atom_idx;
 }
 
@@ -1393,7 +1397,7 @@ pub fn writeSyms(self: *Plan9, buf: *std.ArrayList(u8)) !void {
             const sym = self.syms.items[atom.sym_index.?];
             try self.writeSym(writer, sym);
             if (self.base.comp.module.?.decl_exports.get(decl_index)) |exports| {
-                for (exports.items) |e| if (decl_metadata.getExport(self, ip.stringToSlice(e.opts.name))) |exp_i| {
+                for (exports.items) |e| if (decl_metadata.getExport(self, e.opts.name.toSlice(ip))) |exp_i| {
                     try self.writeSym(writer, self.syms.items[exp_i]);
                 };
             }
@@ -1440,7 +1444,7 @@ pub fn writeSyms(self: *Plan9, buf: *std.ArrayList(u8)) !void {
                 const sym = self.syms.items[atom.sym_index.?];
                 try self.writeSym(writer, sym);
                 if (self.base.comp.module.?.decl_exports.get(decl_index)) |exports| {
-                    for (exports.items) |e| if (decl_metadata.getExport(self, ip.stringToSlice(e.opts.name))) |exp_i| {
+                    for (exports.items) |e| if (decl_metadata.getExport(self, e.opts.name.toSlice(ip))) |exp_i| {
                         const s = self.syms.items[exp_i];
                         if (mem.eql(u8, s.name, "_start"))
                             self.entry_val = s.value;
@@ -1483,25 +1487,25 @@ pub fn getDeclVAddr(
     reloc_info: link.File.RelocInfo,
 ) !u64 {
     const mod = self.base.comp.module.?;
+    const ip = &mod.intern_pool;
     const decl = mod.declPtr(decl_index);
-    log.debug("getDeclVAddr for {s}", .{mod.intern_pool.stringToSlice(decl.name)});
+    log.debug("getDeclVAddr for {}", .{decl.name.fmt(ip)});
     if (decl.isExtern(mod)) {
-        const extern_name = mod.intern_pool.stringToSlice(decl.name);
+        if (decl.name.eqlSlice("etext", ip)) {
-        if (std.mem.eql(u8, extern_name, "etext")) {
             try self.addReloc(reloc_info.parent_atom_index, .{
                 .target = undefined,
                 .offset = reloc_info.offset,
                 .addend = reloc_info.addend,
                 .type = .special_etext,
             });
-        } else if (std.mem.eql(u8, extern_name, "edata")) {
+        } else if (decl.name.eqlSlice("edata", ip)) {
             try self.addReloc(reloc_info.parent_atom_index, .{
                 .target = undefined,
                 .offset = reloc_info.offset,
                 .addend = reloc_info.addend,
                 .type = .special_edata,
             });
-        } else if (std.mem.eql(u8, extern_name, "end")) {
+        } else if (decl.name.eqlSlice("end", ip)) {
             try self.addReloc(reloc_info.parent_atom_index, .{
                 .target = undefined,
                 .offset = reloc_info.offset,

src/link/SpirV.zig

@@ -130,7 +130,7 @@ pub fn updateFunc(self: *SpirV, module: *Module, func_index: InternPool.Index, a
 
     const func = module.funcInfo(func_index);
     const decl = module.declPtr(func.owner_decl);
-    log.debug("lowering function {s}", .{module.intern_pool.stringToSlice(decl.name)});
+    log.debug("lowering function {}", .{decl.name.fmt(&module.intern_pool)});
 
     try self.object.updateFunc(module, func_index, air, liveness);
 }
@@ -141,7 +141,7 @@ pub fn updateDecl(self: *SpirV, module: *Module, decl_index: InternPool.DeclInde
     }
 
     const decl = module.declPtr(decl_index);
-    log.debug("lowering declaration {s}", .{module.intern_pool.stringToSlice(decl.name)});
+    log.debug("lowering declaration {}", .{decl.name.fmt(&module.intern_pool)});
 
     try self.object.updateDecl(module, decl_index);
 }
@@ -178,7 +178,7 @@ pub fn updateExports(
             for (exports) |exp| {
                 try self.object.spv.declareEntryPoint(
                     spv_decl_index,
-                    mod.intern_pool.stringToSlice(exp.opts.name),
+                    exp.opts.name.toSlice(&mod.intern_pool),
                     execution_model,
                 );
             }
@@ -227,14 +227,13 @@ pub fn flushModule(self: *SpirV, arena: Allocator, prog_node: *std.Progress.Node
 
     try error_info.appendSlice("zig_errors");
     const mod = self.base.comp.module.?;
-    for (mod.global_error_set.keys()) |name_nts| {
+    for (mod.global_error_set.keys()) |name| {
-        const name = mod.intern_pool.stringToSlice(name_nts);
         // Errors can contain pretty much any character - to encode them in a string we must escape
         // them somehow. Easiest here is to use some established scheme, one which also preseves the
         // name if it contains no strange characters is nice for debugging. URI encoding fits the bill.
         // We're using : as separator, which is a reserved character.
 
-        const escaped_name = try std.Uri.escapeString(gpa, name);
+        const escaped_name = try std.Uri.escapeString(gpa, name.toSlice(&mod.intern_pool));
         defer gpa.free(escaped_name);
         try error_info.writer().print(":{s}", .{escaped_name});
     }

src/link/Wasm/ZigObject.zig

@@ -258,8 +258,8 @@ pub fn updateDecl(
 
     if (decl.isExtern(mod)) {
         const variable = decl.getOwnedVariable(mod).?;
-        const name = mod.intern_pool.stringToSlice(decl.name);
+        const name = decl.name.toSlice(&mod.intern_pool);
-        const lib_name = mod.intern_pool.stringToSliceUnwrap(variable.lib_name);
+        const lib_name = variable.lib_name.toSlice(&mod.intern_pool);
         return zig_object.addOrUpdateImport(wasm_file, name, atom.sym_index, lib_name, null);
     }
     const val = if (decl.val.getVariable(mod)) |variable| Value.fromInterned(variable.init) else decl.val;
@@ -341,8 +341,8 @@ fn finishUpdateDecl(
     const atom_index = decl_info.atom;
     const atom = wasm_file.getAtomPtr(atom_index);
     const sym = zig_object.symbol(atom.sym_index);
-    const full_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const full_name = try decl.fullyQualifiedName(mod);
-    sym.name = try zig_object.string_table.insert(gpa, full_name);
+    sym.name = try zig_object.string_table.insert(gpa, full_name.toSlice(&mod.intern_pool));
     try atom.code.appendSlice(gpa, code);
     atom.size = @intCast(code.len);
 
@@ -382,7 +382,7 @@ fn finishUpdateDecl(
             // Will be freed upon freeing of decl or after cleanup of Wasm binary.
             const full_segment_name = try std.mem.concat(gpa, u8, &.{
                 segment_name,
-                full_name,
+                full_name.toSlice(&mod.intern_pool),
             });
             errdefer gpa.free(full_segment_name);
             sym.tag = .data;
@@ -427,9 +427,9 @@ pub fn getOrCreateAtomForDecl(zig_object: *ZigObject, wasm_file: *Wasm, decl_ind
         gop.value_ptr.* = .{ .atom = try wasm_file.createAtom(sym_index, zig_object.index) };
         const mod = wasm_file.base.comp.module.?;
         const decl = mod.declPtr(decl_index);
-        const full_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+        const full_name = try decl.fullyQualifiedName(mod);
         const sym = zig_object.symbol(sym_index);
-        sym.name = try zig_object.string_table.insert(gpa, full_name);
+        sym.name = try zig_object.string_table.insert(gpa, full_name.toSlice(&mod.intern_pool));
     }
     return gop.value_ptr.atom;
 }
@@ -478,9 +478,9 @@ pub fn lowerUnnamedConst(zig_object: *ZigObject, wasm_file: *Wasm, val: Value, d
     const parent_atom_index = try zig_object.getOrCreateAtomForDecl(wasm_file, decl_index);
     const parent_atom = wasm_file.getAtom(parent_atom_index);
     const local_index = parent_atom.locals.items.len;
-    const fqn = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+    const fqn = try decl.fullyQualifiedName(mod);
-    const name = try std.fmt.allocPrintZ(gpa, "__unnamed_{s}_{d}", .{
+    const name = try std.fmt.allocPrintZ(gpa, "__unnamed_{}_{d}", .{
-        fqn, local_index,
+        fqn.fmt(&mod.intern_pool), local_index,
     });
     defer gpa.free(name);
 
@@ -623,11 +623,11 @@ fn populateErrorNameTable(zig_object: *ZigObject, wasm_file: *Wasm) !void {
     // Addend for each relocation to the table
     var addend: u32 = 0;
     const mod = wasm_file.base.comp.module.?;
-    for (mod.global_error_set.keys()) |error_name_nts| {
+    for (mod.global_error_set.keys()) |error_name| {
         const atom = wasm_file.getAtomPtr(atom_index);
 
-        const error_name = mod.intern_pool.stringToSlice(error_name_nts);
+        const error_name_slice = error_name.toSlice(&mod.intern_pool);
-        const len: u32 = @intCast(error_name.len + 1); // names are 0-terminated
+        const len: u32 = @intCast(error_name_slice.len + 1); // names are 0-terminated
 
         const slice_ty = Type.slice_const_u8_sentinel_0;
         const offset = @as(u32, @intCast(atom.code.items.len));
@@ -646,10 +646,9 @@ fn populateErrorNameTable(zig_object: *ZigObject, wasm_file: *Wasm) !void {
 
         // as we updated the error name table, we now store the actual name within the names atom
         try names_atom.code.ensureUnusedCapacity(gpa, len);
-        names_atom.code.appendSliceAssumeCapacity(error_name);
+        names_atom.code.appendSliceAssumeCapacity(error_name_slice[0..len]);
-        names_atom.code.appendAssumeCapacity(0);
 
-        log.debug("Populated error name: '{s}'", .{error_name});
+        log.debug("Populated error name: '{}'", .{error_name.fmt(&mod.intern_pool)});
     }
     names_atom.size = addend;
     zig_object.error_names_atom = names_atom_index;
@@ -833,8 +832,7 @@ pub fn deleteDeclExport(
 ) void {
     const mod = wasm_file.base.comp.module.?;
     const decl_info = zig_object.decls_map.getPtr(decl_index) orelse return;
-    const export_name = mod.intern_pool.stringToSlice(name);
+    if (decl_info.@"export"(zig_object, name.toSlice(&mod.intern_pool))) |sym_index| {
-    if (decl_info.@"export"(zig_object, export_name)) |sym_index| {
         const sym = zig_object.symbol(sym_index);
         decl_info.deleteExport(sym_index);
         std.debug.assert(zig_object.global_syms.remove(sym.name));
@@ -864,10 +862,10 @@ pub fn updateExports(
     const atom = wasm_file.getAtom(atom_index);
     const atom_sym = atom.symbolLoc().getSymbol(wasm_file).*;
     const gpa = mod.gpa;
-    log.debug("Updating exports for decl '{s}'", .{mod.intern_pool.stringToSlice(decl.name)});
+    log.debug("Updating exports for decl '{}'", .{decl.name.fmt(&mod.intern_pool)});
 
     for (exports) |exp| {
-        if (mod.intern_pool.stringToSliceUnwrap(exp.opts.section)) |section| {
+        if (exp.opts.section.toSlice(&mod.intern_pool)) |section| {
             try mod.failed_exports.putNoClobber(gpa, exp, try Module.ErrorMsg.create(
                 gpa,
                 decl.srcLoc(mod),
@@ -877,10 +875,8 @@ pub fn updateExports(
             continue;
         }
 
-        const export_string = mod.intern_pool.stringToSlice(exp.opts.name);
+        const export_string = exp.opts.name.toSlice(&mod.intern_pool);
-        const sym_index = if (decl_info.@"export"(zig_object, export_string)) |idx|
+        const sym_index = if (decl_info.@"export"(zig_object, export_string)) |idx| idx else index: {
-            idx
-        else index: {
             const sym_index = try zig_object.allocateSymbol(gpa);
             try decl_info.appendExport(gpa, sym_index);
             break :index sym_index;
@@ -1089,9 +1085,9 @@ pub fn createDebugSectionForIndex(zig_object: *ZigObject, wasm_file: *Wasm, inde
 pub fn updateDeclLineNumber(zig_object: *ZigObject, mod: *Module, decl_index: InternPool.DeclIndex) !void {
     if (zig_object.dwarf) |*dw| {
         const decl = mod.declPtr(decl_index);
-        const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
+        const decl_name = try decl.fullyQualifiedName(mod);
 
-        log.debug("updateDeclLineNumber {s}{*}", .{ decl_name, decl });
+        log.debug("updateDeclLineNumber {}{*}", .{ decl_name.fmt(&mod.intern_pool), decl });
         try dw.updateDeclLineNumber(mod, decl_index);
     }
 }

src/mutable_value.zig

@@ -73,7 +73,7 @@ pub const MutableValue = union(enum) {
             } }),
             .bytes => |b| try ip.get(gpa, .{ .aggregate = .{
                 .ty = b.ty,
-                .storage = .{ .bytes = b.data },
+                .storage = .{ .bytes = try ip.getOrPutString(gpa, b.data, .maybe_embedded_nulls) },
             } }),
             .aggregate => |a| {
                 const elems = try arena.alloc(InternPool.Index, a.elems.len);
@@ -158,18 +158,18 @@ pub const MutableValue = union(enum) {
                 },
                 .aggregate => |agg| switch (agg.storage) {
                     .bytes => |bytes| {
-                        assert(bytes.len == ip.aggregateTypeLenIncludingSentinel(agg.ty));
+                        const len: usize = @intCast(ip.aggregateTypeLenIncludingSentinel(agg.ty));
                         assert(ip.childType(agg.ty) == .u8_type);
                         if (allow_bytes) {
-                            const arena_bytes = try arena.alloc(u8, bytes.len);
+                            const arena_bytes = try arena.alloc(u8, len);
-                            @memcpy(arena_bytes, bytes);
+                            @memcpy(arena_bytes, bytes.toSlice(len, ip));
                             mv.* = .{ .bytes = .{
                                 .ty = agg.ty,
                                 .data = arena_bytes,
                             } };
                         } else {
-                            const mut_elems = try arena.alloc(MutableValue, bytes.len);
+                            const mut_elems = try arena.alloc(MutableValue, len);
-                            for (bytes, mut_elems) |b, *mut_elem| {
+                            for (bytes.toSlice(len, ip), mut_elems) |b, *mut_elem| {
                                 mut_elem.* = .{ .interned = try ip.get(gpa, .{ .int = .{
                                     .ty = .u8_type,
                                     .storage = .{ .u64 = b },

src/print_value.zig

@@ -204,26 +204,35 @@ fn printAggregate(
             try writer.writeAll(" }");
             return;
         },
-        .Array => if (aggregate.storage == .bytes and aggregate.storage.bytes.len > 0) {
+        .Array => {
-            const skip_terminator = aggregate.storage.bytes[aggregate.storage.bytes.len - 1] == 0;
+            switch (aggregate.storage) {
-            const bytes = if (skip_terminator) b: {
+                .bytes => |bytes| string: {
-                break :b aggregate.storage.bytes[0 .. aggregate.storage.bytes.len - 1];
+                    const len = ty.arrayLenIncludingSentinel(zcu);
-            } else aggregate.storage.bytes;
+                    if (len == 0) break :string;
-            try writer.print("\"{}\"", .{std.zig.fmtEscapes(bytes)});
+                    const slice = bytes.toSlice(if (bytes.at(len - 1, ip) == 0) len - 1 else len, ip);
-            if (!is_ref) try writer.writeAll(".*");
+                    try writer.print("\"{}\"", .{std.zig.fmtEscapes(slice)});
-            return;
+                    if (!is_ref) try writer.writeAll(".*");
-        } else if (ty.arrayLen(zcu) == 0) {
+                    return;
-            if (is_ref) try writer.writeByte('&');
+                },
-            return writer.writeAll(".{}");
+                .elems, .repeated_elem => {},
-        } else if (ty.arrayLen(zcu) == 1) one_byte_str: {
+            }
-            // The repr isn't `bytes`, but we might still be able to print this as a string
+            switch (ty.arrayLen(zcu)) {
-            if (ty.childType(zcu).toIntern() != .u8_type) break :one_byte_str;
+                0 => {
-            const elem_val = Value.fromInterned(aggregate.storage.values()[0]);
+                    if (is_ref) try writer.writeByte('&');
-            if (elem_val.isUndef(zcu)) break :one_byte_str;
+                    return writer.writeAll(".{}");
-            const byte = elem_val.toUnsignedInt(zcu);
+                },
-            try writer.print("\"{}\"", .{std.zig.fmtEscapes(&.{@intCast(byte)})});
+                1 => one_byte_str: {
-            if (!is_ref) try writer.writeAll(".*");
+                    // The repr isn't `bytes`, but we might still be able to print this as a string
-            return;
+                    if (ty.childType(zcu).toIntern() != .u8_type) break :one_byte_str;
+                    const elem_val = Value.fromInterned(aggregate.storage.values()[0]);
+                    if (elem_val.isUndef(zcu)) break :one_byte_str;
+                    const byte = elem_val.toUnsignedInt(zcu);
+                    try writer.print("\"{}\"", .{std.zig.fmtEscapes(&.{@intCast(byte)})});
+                    if (!is_ref) try writer.writeAll(".*");
+                    return;
+                },
+                else => {},
+            }
         },
         .Vector => if (ty.arrayLen(zcu) == 0) {
             if (is_ref) try writer.writeByte('&');

src/type.zig

@@ -490,18 +490,10 @@ pub const Type = struct {
                     };
                 },
                 .anyframe_type => true,
-                .array_type => |array_type| {
+                .array_type => |array_type| return array_type.lenIncludingSentinel() > 0 and
-                    if (array_type.sentinel != .none) {
+                    try Type.fromInterned(array_type.child).hasRuntimeBitsAdvanced(mod, ignore_comptime_only, strat),
-                        return Type.fromInterned(array_type.child).hasRuntimeBitsAdvanced(mod, ignore_comptime_only, strat);
+                .vector_type => |vector_type| return vector_type.len > 0 and
-                    } else {
+                    try Type.fromInterned(vector_type.child).hasRuntimeBitsAdvanced(mod, ignore_comptime_only, strat),
-                        return array_type.len > 0 and
-                            try Type.fromInterned(array_type.child).hasRuntimeBitsAdvanced(mod, ignore_comptime_only, strat);
-                    }
-                },
-                .vector_type => |vector_type| {
-                    return vector_type.len > 0 and
-                        try Type.fromInterned(vector_type.child).hasRuntimeBitsAdvanced(mod, ignore_comptime_only, strat);
-                },
                 .opt_type => |child| {
                     const child_ty = Type.fromInterned(child);
                     if (child_ty.isNoReturn(mod)) {
@@ -1240,7 +1232,7 @@ pub const Type = struct {
                 .anyframe_type => return AbiSizeAdvanced{ .scalar = @divExact(target.ptrBitWidth(), 8) },
 
                 .array_type => |array_type| {
-                    const len = array_type.len + @intFromBool(array_type.sentinel != .none);
+                    const len = array_type.lenIncludingSentinel();
                     if (len == 0) return .{ .scalar = 0 };
                     switch (try Type.fromInterned(array_type.child).abiSizeAdvanced(mod, strat)) {
                         .scalar => |elem_size| return .{ .scalar = len * elem_size },
@@ -1577,7 +1569,7 @@ pub const Type = struct {
             .anyframe_type => return target.ptrBitWidth(),
 
             .array_type => |array_type| {
-                const len = array_type.len + @intFromBool(array_type.sentinel != .none);
+                const len = array_type.lenIncludingSentinel();
                 if (len == 0) return 0;
                 const elem_ty = Type.fromInterned(array_type.child);
                 const elem_size = @max(
@@ -1731,7 +1723,7 @@ pub const Type = struct {
             .struct_type => ip.loadStructType(ty.toIntern()).haveLayout(ip),
             .union_type => ip.loadUnionType(ty.toIntern()).haveLayout(ip),
             .array_type => |array_type| {
-                if ((array_type.len + @intFromBool(array_type.sentinel != .none)) == 0) return true;
+                if (array_type.lenIncludingSentinel() == 0) return true;
                 return Type.fromInterned(array_type.child).layoutIsResolved(mod);
             },
             .opt_type => |child| Type.fromInterned(child).layoutIsResolved(mod),