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Sema: properly handle noreturn fields in unions

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This commit is contained in:
Veikka Tuominen 2022-08-17 15:07:20 +03:00
parent b0a55e1b3b
commit c3d5428cba
5 changed files with 270 additions and 34 deletions
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202
src/Sema.zig
View File

@ -3772,6 +3772,7 @@ fn validateStructInit(
}
var root_msg: ?*Module.ErrorMsg = null;
errdefer if (root_msg) |msg| msg.destroy(sema.gpa);
const struct_ptr = try sema.resolveInst(struct_ptr_zir_ref);
if ((is_comptime or block.is_comptime) and
@ -3947,6 +3948,7 @@ fn validateStructInit(
}
if (root_msg) |msg| {
root_msg = null;
if (struct_ty.castTag(.@"struct")) |struct_obj| {
const fqn = try struct_obj.data.getFullyQualifiedName(sema.mod);
defer gpa.free(fqn);
@ -4005,6 +4007,8 @@ fn zirValidateArrayInit(
if (instrs.len != array_len and array_ty.isTuple()) {
const struct_obj = array_ty.castTag(.tuple).?.data;
var root_msg: ?*Module.ErrorMsg = null;
errdefer if (root_msg) |msg| msg.destroy(sema.gpa);
for (struct_obj.values) |default_val, i| {
if (i < instrs.len) continue;
@ -4019,6 +4023,7 @@ fn zirValidateArrayInit(
}
if (root_msg) |msg| {
root_msg = null;
return sema.failWithOwnedErrorMsg(msg);
}
}
@ -8964,12 +8969,15 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
},
};
const union_originally = blk: {
const maybe_union_ty = blk: {
const zir_data = sema.code.instructions.items(.data);
const cond_index = Zir.refToIndex(extra.data.operand).?;
const raw_operand = sema.resolveInst(zir_data[cond_index].un_node.operand) catch unreachable;
break :blk sema.typeOf(raw_operand).zigTypeTag() == .Union;
break :blk sema.typeOf(raw_operand);
};
const union_originally = maybe_union_ty.zigTypeTag() == .Union;
var seen_union_fields: []?Module.SwitchProngSrc = &.{};
defer gpa.free(seen_union_fields);
const operand_ty = sema.typeOf(operand);
@ -9004,7 +9012,8 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
.Union => unreachable, // handled in zirSwitchCond
.Enum => {
var seen_fields = try gpa.alloc(?Module.SwitchProngSrc, operand_ty.enumFieldCount());
defer gpa.free(seen_fields);
defer if (!union_originally) gpa.free(seen_fields);
if (union_originally) seen_union_fields = seen_fields;
mem.set(?Module.SwitchProngSrc, seen_fields, null);
// This is used for non-exhaustive enum values that do not correspond to any tags.
@ -9637,18 +9646,28 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
const item = try sema.resolveInst(item_ref);
// `item` is already guaranteed to be constant known.
_ = sema.analyzeBodyInner(&case_block, body) catch |err| switch (err) {
error.ComptimeBreak => {
const zir_datas = sema.code.instructions.items(.data);
const break_data = zir_datas[sema.comptime_break_inst].@"break";
try sema.addRuntimeBreak(&case_block, .{
.block_inst = break_data.block_inst,
.operand = break_data.operand,
.inst = sema.comptime_break_inst,
});
},
else => |e| return e,
};
const analyze_body = if (union_originally) blk: {
const item_val = sema.resolveConstValue(block, .unneeded, item, undefined) catch unreachable;
const field_ty = maybe_union_ty.unionFieldType(item_val, sema.mod);
break :blk field_ty.zigTypeTag() != .NoReturn;
} else true;
if (analyze_body) {
_ = sema.analyzeBodyInner(&case_block, body) catch |err| switch (err) {
error.ComptimeBreak => {
const zir_datas = sema.code.instructions.items(.data);
const break_data = zir_datas[sema.comptime_break_inst].@"break";
try sema.addRuntimeBreak(&case_block, .{
.block_inst = break_data.block_inst,
.operand = break_data.operand,
.inst = sema.comptime_break_inst,
});
},
else => |e| return e,
};
} else {
_ = try case_block.addNoOp(.unreach);
}
try wip_captures.finalize();
@ -9689,20 +9708,34 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
if (ranges_len == 0) {
cases_len += 1;
const analyze_body = if (union_originally)
for (items) |item_ref| {
const item = try sema.resolveInst(item_ref);
const item_val = sema.resolveConstValue(block, .unneeded, item, undefined) catch unreachable;
const field_ty = maybe_union_ty.unionFieldType(item_val, sema.mod);
if (field_ty.zigTypeTag() != .NoReturn) break true;
} else false
else
true;
const body = sema.code.extra[extra_index..][0..body_len];
extra_index += body_len;
_ = sema.analyzeBodyInner(&case_block, body) catch |err| switch (err) {
error.ComptimeBreak => {
const zir_datas = sema.code.instructions.items(.data);
const break_data = zir_datas[sema.comptime_break_inst].@"break";
try sema.addRuntimeBreak(&case_block, .{
.block_inst = break_data.block_inst,
.operand = break_data.operand,
.inst = sema.comptime_break_inst,
});
},
else => |e| return e,
};
if (analyze_body) {
_ = sema.analyzeBodyInner(&case_block, body) catch |err| switch (err) {
error.ComptimeBreak => {
const zir_datas = sema.code.instructions.items(.data);
const break_data = zir_datas[sema.comptime_break_inst].@"break";
try sema.addRuntimeBreak(&case_block, .{
.block_inst = break_data.block_inst,
.operand = break_data.operand,
.inst = sema.comptime_break_inst,
});
},
else => |e| return e,
};
} else {
_ = try case_block.addNoOp(.unreach);
}
try cases_extra.ensureUnusedCapacity(gpa, 2 + items.len +
case_block.instructions.items.len);
@ -9824,7 +9857,17 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
case_block.instructions.shrinkRetainingCapacity(0);
case_block.wip_capture_scope = wip_captures.scope;
if (special.body.len != 0) {
const analyze_body = if (union_originally)
for (seen_union_fields) |seen_field, index| {
if (seen_field != null) continue;
const union_obj = maybe_union_ty.cast(Type.Payload.Union).?.data;
const field_ty = union_obj.fields.values()[index].ty;
if (field_ty.zigTypeTag() != .NoReturn) break true;
} else false
else
true;
if (special.body.len != 0 and analyze_body) {
_ = sema.analyzeBodyInner(&case_block, special.body) catch |err| switch (err) {
error.ComptimeBreak => {
const zir_datas = sema.code.instructions.items(.data);
@ -13225,6 +13268,14 @@ fn analyzeCmpUnionTag(
const coerced_tag = try sema.coerce(block, union_tag_ty, tag, tag_src);
const coerced_union = try sema.coerce(block, union_tag_ty, un, un_src);
if (try sema.resolveMaybeUndefVal(block, tag_src, coerced_tag)) |enum_val| {
if (enum_val.isUndef()) return sema.addConstUndef(Type.bool);
const field_ty = union_ty.unionFieldType(enum_val, sema.mod);
if (field_ty.zigTypeTag() == .NoReturn) {
return Air.Inst.Ref.bool_false;
}
}
return sema.cmpSelf(block, src, coerced_union, coerced_tag, op, un_src, tag_src);
}
@ -15579,6 +15630,8 @@ fn finishStructInit(
const gpa = sema.gpa;
var root_msg: ?*Module.ErrorMsg = null;
errdefer if (root_msg) |msg| msg.destroy(sema.gpa);
if (struct_ty.isAnonStruct()) {
const struct_obj = struct_ty.castTag(.anon_struct).?.data;
for (struct_obj.values) |default_val, i| {
@ -15634,6 +15687,7 @@ fn finishStructInit(
}
if (root_msg) |msg| {
root_msg = null;
if (struct_ty.castTag(.@"struct")) |struct_obj| {
const fqn = try struct_obj.data.getFullyQualifiedName(sema.mod);
defer gpa.free(fqn);
@ -21682,6 +21736,18 @@ fn unionFieldPtr(
.@"addrspace" = union_ptr_ty.ptrAddressSpace(),
});
if (initializing and field.ty.zigTypeTag() == .NoReturn) {
const msg = msg: {
const msg = try sema.errMsg(block, src, "cannot initialize 'noreturn' field of union", .{});
errdefer msg.destroy(sema.gpa);
try sema.addFieldErrNote(block, union_ty, field_index, msg, "field '{s}' declared here", .{field_name});
try sema.addDeclaredHereNote(msg, union_ty);
break :msg msg;
};
return sema.failWithOwnedErrorMsg(msg);
}
if (try sema.resolveDefinedValue(block, src, union_ptr)) |union_ptr_val| ct: {
switch (union_obj.layout) {
.Auto => if (!initializing) {
@ -21734,6 +21800,10 @@ fn unionFieldPtr(
const ok = try block.addBinOp(.cmp_eq, active_tag, wanted_tag);
try sema.addSafetyCheck(block, ok, .inactive_union_field);
}
if (field.ty.zigTypeTag() == .NoReturn) {
_ = try block.addNoOp(.unreach);
return Air.Inst.Ref.unreachable_value;
}
return block.addStructFieldPtr(union_ptr, field_index, ptr_field_ty);
}
@ -21802,6 +21872,10 @@ fn unionFieldVal(
const ok = try block.addBinOp(.cmp_eq, active_tag, wanted_tag);
try sema.addSafetyCheck(block, ok, .inactive_union_field);
}
if (field.ty.zigTypeTag() == .NoReturn) {
_ = try block.addNoOp(.unreach);
return Air.Inst.Ref.unreachable_value;
}
return block.addStructFieldVal(union_byval, field_index, field.ty);
}
@ -25002,6 +25076,18 @@ fn coerceEnumToUnion(
};
const field = union_obj.fields.values()[field_index];
const field_ty = try sema.resolveTypeFields(block, inst_src, field.ty);
if (field_ty.zigTypeTag() == .NoReturn) {
const msg = msg: {
const msg = try sema.errMsg(block, inst_src, "cannot initialize 'noreturn' field of union", .{});
errdefer msg.destroy(sema.gpa);
const field_name = union_obj.fields.keys()[field_index];
try sema.addFieldErrNote(block, union_ty, field_index, msg, "field '{s}' declared here", .{field_name});
try sema.addDeclaredHereNote(msg, union_ty);
break :msg msg;
};
return sema.failWithOwnedErrorMsg(msg);
}
const opv = (try sema.typeHasOnePossibleValue(block, inst_src, field_ty)) orelse {
const msg = msg: {
const field_name = union_obj.fields.keys()[field_index];
@ -25037,13 +25123,37 @@ fn coerceEnumToUnion(
return sema.failWithOwnedErrorMsg(msg);
}
const union_obj = union_ty.cast(Type.Payload.Union).?.data;
{
var msg: ?*Module.ErrorMsg = null;
errdefer if (msg) |some| some.destroy(sema.gpa);
for (union_obj.fields.values()) |field, i| {
if (field.ty.zigTypeTag() == .NoReturn) {
const err_msg = msg orelse try sema.errMsg(
block,
inst_src,
"runtime coercion from enum '{}' to union '{}' which has a 'noreturn' field",
.{ tag_ty.fmt(sema.mod), union_ty.fmt(sema.mod) },
);
msg = err_msg;
try sema.addFieldErrNote(block, union_ty, i, err_msg, "'noreturn' field here", .{});
}
}
if (msg) |some| {
msg = null;
try sema.addDeclaredHereNote(some, union_ty);
return sema.failWithOwnedErrorMsg(some);
}
}
// If the union has all fields 0 bits, the union value is just the enum value.
if (union_ty.unionHasAllZeroBitFieldTypes()) {
return block.addBitCast(union_ty, enum_tag);
}
const msg = msg: {
const union_obj = union_ty.cast(Type.Payload.Union).?.data;
const msg = try sema.errMsg(
block,
inst_src,
@ -25054,11 +25164,11 @@ fn coerceEnumToUnion(
var it = union_obj.fields.iterator();
var field_index: usize = 0;
while (it.next()) |field| {
while (it.next()) |field| : (field_index += 1) {
const field_name = field.key_ptr.*;
const field_ty = field.value_ptr.ty;
if (!field_ty.hasRuntimeBits()) continue;
try sema.addFieldErrNote(block, union_ty, field_index, msg, "field '{s}' has type '{}'", .{ field_name, field_ty.fmt(sema.mod) });
field_index += 1;
}
try sema.addDeclaredHereNote(msg, union_ty);
break :msg msg;
@ -25361,6 +25471,7 @@ fn coerceTupleToStruct(
// Populate default field values and report errors for missing fields.
var root_msg: ?*Module.ErrorMsg = null;
errdefer if (root_msg) |msg| msg.destroy(sema.gpa);
for (field_refs) |*field_ref, i| {
if (field_ref.* != .none) continue;
@ -25386,6 +25497,7 @@ fn coerceTupleToStruct(
}
if (root_msg) |msg| {
root_msg = null;
try sema.addDeclaredHereNote(msg, struct_ty);
return sema.failWithOwnedErrorMsg(msg);
}
@ -25455,6 +25567,7 @@ fn coerceTupleToTuple(
// Populate default field values and report errors for missing fields.
var root_msg: ?*Module.ErrorMsg = null;
errdefer if (root_msg) |msg| msg.destroy(sema.gpa);
for (field_refs) |*field_ref, i| {
if (field_ref.* != .none) continue;
@ -25490,6 +25603,7 @@ fn coerceTupleToTuple(
}
if (root_msg) |msg| {
root_msg = null;
try sema.addDeclaredHereNote(msg, tuple_ty);
return sema.failWithOwnedErrorMsg(msg);
}
@ -27914,6 +28028,18 @@ fn semaStructFields(mod: *Module, struct_obj: *Module.Struct) CompileError!void
};
return sema.failWithOwnedErrorMsg(msg);
}
if (field_ty.zigTypeTag() == .NoReturn) {
const msg = msg: {
const tree = try sema.getAstTree(&block_scope);
const field_src = enumFieldSrcLoc(decl, tree.*, 0, i);
const msg = try sema.errMsg(&block_scope, field_src, "struct fields cannot be 'noreturn'", .{});
errdefer msg.destroy(sema.gpa);
try sema.addDeclaredHereNote(msg, field_ty);
break :msg msg;
};
return sema.failWithOwnedErrorMsg(msg);
}
if (struct_obj.layout == .Extern and !sema.validateExternType(field.ty, .other)) {
const msg = msg: {
const tree = try sema.getAstTree(&block_scope);
@ -28725,6 +28851,16 @@ fn enumFieldSrcLoc(
.container_decl_arg_trailing,
=> tree.containerDeclArg(enum_node),
.tagged_union,
.tagged_union_trailing,
=> tree.taggedUnion(enum_node),
.tagged_union_two,
.tagged_union_two_trailing,
=> tree.taggedUnionTwo(&buffer, enum_node),
.tagged_union_enum_tag,
.tagged_union_enum_tag_trailing,
=> tree.taggedUnionEnumTag(enum_node),
// Container was constructed with `@Type`.
else => return LazySrcLoc.nodeOffset(0),
};
@ -29375,7 +29511,9 @@ fn unionFieldAlignment(
src: LazySrcLoc,
field: Module.Union.Field,
) !u32 {
if (field.abi_align == 0) {
if (field.ty.zigTypeTag() == .NoReturn) {
return @as(u32, 0);
} else if (field.abi_align == 0) {
return sema.typeAbiAlignment(block, src, field.ty);
} else {
return field.abi_align;

45
test/behavior/union.zig
View File

@ -1256,3 +1256,48 @@ test "return an extern union from C calling convention" {
});
try expect(u.d == 4.0);
}
test "noreturn field in union" {
if (builtin.zig_backend == .stage1) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
const U = union(enum) {
a: u32,
b: noreturn,
c: noreturn,
};
var a = U{ .a = 1 };
var count: u32 = 0;
if (a == .b) @compileError("bad");
switch (a) {
.a => count += 1,
.b => |val| {
_ = val;
@compileError("bad");
},
.c => @compileError("bad"),
}
switch (a) {
.a => count += 1,
.b, .c => @compileError("bad"),
}
switch (a) {
.a, .b, .c => {
count += 1;
try expect(a == .a);
},
}
switch (a) {
.a => count += 1,
else => @compileError("bad"),
}
switch (a) {
else => {
count += 1;
try expect(a == .a);
},
}
try expect(count == 5);
}

12
test/cases/compile_errors/noreturn_struct_field.zig Normal file
View File

@ -0,0 +1,12 @@
const S = struct {
s: noreturn,
};
comptime {
_ = @typeInfo(S);
}
// error
// backend=stage2
// target=native
//
// :2:5: error: struct fields cannot be 'noreturn'

2
test/cases/compile_errors/runtime_cast_to_union_which_has_non-void_fields.zig
View File

@ -18,6 +18,4 @@ fn foo(l: Letter) void {
//
// :11:20: error: runtime coercion from enum 'tmp.Letter' to union 'tmp.Value' which has non-void fields
// :3:5: note: field 'A' has type 'i32'
// :4:5: note: field 'B' has type 'void'
// :5:5: note: field 'C' has type 'void'
// :2:15: note: union declared here

43
test/cases/compile_errors/union_noreturn_field_initialized.zig Normal file
View File

@ -0,0 +1,43 @@
pub export fn entry1() void {
const U = union(enum) {
a: u32,
b: noreturn,
fn foo(_: @This()) void {}
fn bar() noreturn {
unreachable;
}
};
var a = U{ .b = undefined };
_ = a;
}
pub export fn entry2() void {
const U = union(enum) {
a: noreturn,
};
var u: U = undefined;
u = .a;
}
pub export fn entry3() void {
const U = union(enum) {
a: noreturn,
b: void,
};
var e = @typeInfo(U).Union.tag_type.?.a;
var u: U = undefined;
u = e;
}
// error
// backend=stage2
// target=native
//
// :11:21: error: cannot initialize 'noreturn' field of union
// :4:9: note: field 'b' declared here
// :2:15: note: union declared here
// :19:10: error: cannot initialize 'noreturn' field of union
// :16:9: note: field 'a' declared here
// :15:15: note: union declared here
// :28:9: error: runtime coercion from enum '@typeInfo(tmp.entry3.U).Union.tag_type.?' to union 'tmp.entry3.U' which has a 'noreturn' field
// :23:9: note: 'noreturn' field here
// :22:15: note: union declared here