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wasm-linker: feature verifiction for shared-mem

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When the user enables shared-memory, we must ensure the linked objects
have the 'atomics' and 'bulk-memory' features allowed.
This commit is contained in:
Luuk de Gram 2023-03-13 19:30:33 +01:00
parent 09abd53da7
commit fb9d3cd50e
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GPG Key ID: A8CFE58E4DC7D664
3 changed files with 47 additions and 10 deletions
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41
src/link/Wasm.zig
View File

@ -795,6 +795,8 @@ fn validateFeatures(
// when false, we fail linking. We only verify this after a loop to catch all invalid features.
var valid_feature_set = true;
// will be set to true when there's any TLS segment found in any of the object files
var has_tls = false;
// When the user has given an explicit list of features to enable,
// we extract them and insert each into the 'allowed' list.
@ -825,6 +827,12 @@ fn validateFeatures(
},
}
}
for (object.segment_info) |segment| {
if (segment.isTLS()) {
has_tls = true;
}
}
}
// when we infer the features, we allow each feature found in the 'used' set
@ -836,7 +844,7 @@ fn validateFeatures(
allowed[used_index] = is_enabled;
emit_features_count.* += @boolToInt(is_enabled);
} else if (is_enabled and !allowed[used_index]) {
log.err("feature '{s}' not allowed, but used by linked object", .{(@intToEnum(types.Feature.Tag, used_index)).toString()});
log.err("feature '{}' not allowed, but used by linked object", .{@intToEnum(types.Feature.Tag, used_index)});
log.err(" defined in '{s}'", .{wasm.objects.items[used_set >> 1].name});
valid_feature_set = false;
}
@ -846,6 +854,30 @@ fn validateFeatures(
return error.InvalidFeatureSet;
}
if (wasm.base.options.shared_memory) {
const disallowed_feature = disallowed[@enumToInt(types.Feature.Tag.shared_mem)];
if (@truncate(u1, disallowed_feature) != 0) {
log.err(
"shared-memory is disallowed by '{s}' because it wasn't compiled with 'atomics' and 'bulk-memory' features enabled",
.{wasm.objects.items[disallowed_feature >> 1].name},
);
valid_feature_set = false;
}
for ([_]types.Feature.Tag{ .atomics, .bulk_memory }) |feature| {
if (!allowed[@enumToInt(feature)]) {
log.err("feature '{}' is not used but is required for shared-memory", .{feature});
}
}
}
if (has_tls) {
for ([_]types.Feature.Tag{ .atomics, .bulk_memory }) |feature| {
if (!allowed[@enumToInt(feature)]) {
log.err("feature '{}' is not used but is required for thread-local storage", .{feature});
}
}
}
// For each linked object, validate the required and disallowed features
for (wasm.objects.items) |object| {
var object_used_features = [_]bool{false} ** known_features_count;
@ -854,7 +886,7 @@ fn validateFeatures(
// from here a feature is always used
const disallowed_feature = disallowed[@enumToInt(feature.tag)];
if (@truncate(u1, disallowed_feature) != 0) {
log.err("feature '{s}' is disallowed, but used by linked object", .{feature.tag.toString()});
log.err("feature '{}' is disallowed, but used by linked object", .{feature.tag});
log.err(" disallowed by '{s}'", .{wasm.objects.items[disallowed_feature >> 1].name});
log.err(" used in '{s}'", .{object.name});
valid_feature_set = false;
@ -867,7 +899,7 @@ fn validateFeatures(
for (required, 0..) |required_feature, feature_index| {
const is_required = @truncate(u1, required_feature) != 0;
if (is_required and !object_used_features[feature_index]) {
log.err("feature '{s}' is required but not used in linked object", .{(@intToEnum(types.Feature.Tag, feature_index)).toString()});
log.err("feature '{}' is required but not used in linked object", .{@intToEnum(types.Feature.Tag, feature_index)});
log.err(" required by '{s}'", .{wasm.objects.items[required_feature >> 1].name});
log.err(" missing in '{s}'", .{object.name});
valid_feature_set = false;
@ -3432,7 +3464,8 @@ fn emitFeaturesSection(binary_bytes: *std.ArrayList(u8), enabled_features: []con
if (enabled) {
const feature: types.Feature = .{ .prefix = .used, .tag = @intToEnum(types.Feature.Tag, feature_index) };
try leb.writeULEB128(writer, @enumToInt(feature.prefix));
const string = feature.tag.toString();
var buf: [100]u8 = undefined;
const string = try std.fmt.bufPrint(&buf, "{}", .{feature.tag});
try leb.writeULEB128(writer, @intCast(u32, string.len));
try writer.writeAll(string);
}

4
src/link/Wasm/Object.zig
View File

@ -601,8 +601,8 @@ fn Parser(comptime ReaderType: type) type {
});
for (relocations) |*relocation| {
const rel_type = try leb.readULEB128(u8, reader);
const rel_type_enum = @intToEnum(types.Relocation.RelocationType, rel_type);
const rel_type = try reader.readByte();
const rel_type_enum = std.meta.intToEnum(types.Relocation.RelocationType, rel_type) catch return error.MalformedSection;
relocation.* = .{
.relocation_type = rel_type_enum,
.offset = try leb.readULEB128(u32, reader),

12
src/link/Wasm/types.zig
View File

@ -50,6 +50,8 @@ pub const Relocation = struct {
.R_WASM_MEMORY_ADDR_LEB64,
.R_WASM_MEMORY_ADDR_SLEB64,
.R_WASM_MEMORY_ADDR_I64,
.R_WASM_MEMORY_ADDR_TLS_SLEB,
.R_WASM_MEMORY_ADDR_TLS_SLEB64,
.R_WASM_FUNCTION_OFFSET_I32,
.R_WASM_SECTION_OFFSET_I32,
=> true,
@ -218,8 +220,10 @@ pub const Feature = struct {
return @intToEnum(Tag, @enumToInt(feature));
}
pub fn toString(tag: Tag) []const u8 {
return switch (tag) {
pub fn format(tag: Tag, comptime fmt: []const u8, opt: std.fmt.FormatOptions, writer: anytype) !void {
_ = fmt;
_ = opt;
try writer.writeAll(switch (tag) {
.atomics => "atomics",
.bulk_memory => "bulk-memory",
.exception_handling => "exception-handling",
@ -233,7 +237,7 @@ pub const Feature = struct {
.simd128 => "simd128",
.tail_call => "tail-call",
.shared_mem => "shared-mem",
};
});
}
};
@ -246,7 +250,7 @@ pub const Feature = struct {
pub fn format(feature: Feature, comptime fmt: []const u8, opt: std.fmt.FormatOptions, writer: anytype) !void {
_ = opt;
_ = fmt;
try writer.print("{c} {s}", .{ feature.prefix, feature.tag.toString() });
try writer.print("{c} {}", .{ feature.prefix, feature.tag });
}
};