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stage2: packed struct fields do not have a byte offset

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This commit is contained in:
Veikka Tuominen 2022-05-25 18:08:51 +03:00
parent b0e8bf15f5
commit d214b6bdf0
3 changed files with 27 additions and 1 deletions
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6
src/Sema.zig
View File

@ -20197,7 +20197,11 @@ fn beginComptimePtrLoad(
var deref = try beginComptimePtrLoad(sema, block, src, field_ptr.container_ptr, field_ptr.container_ty);
if (field_ptr.container_ty.hasWellDefinedLayout()) {
if (deref.parent) |*parent| {
const struct_ty = field_ptr.container_ty.castTag(.@"struct");
if (struct_ty != null and struct_ty.?.data.layout == .Packed) {
// packed structs are not byte addressable
deref.parent = null;
} else if (deref.parent) |*parent| {
// Update the byte offset (in-place)
try sema.resolveTypeLayout(block, src, field_ptr.container_ty);
const field_offset = field_ptr.container_ty.structFieldOffset(field_index, target);

1
src/value.zig
View File

@ -2645,6 +2645,7 @@ pub const Value = extern union {
}
unreachable;
},
.undef => return Value.undef,
else => unreachable,
}

21
test/behavior/struct.zig
View File

@ -1319,3 +1319,24 @@ test "packed struct aggregate init" {
const result = @bitCast(u8, S.foo(1, 2));
try expect(result == 9);
}
test "packed struct field access via pointer" {
if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
const S = struct {
fn doTheTest() !void {
const S = packed struct { a: u30 };
var s1: S = .{ .a = 1 };
var s2 = &s1;
try expect(s2.a == 1);
var s3: S = undefined;
var s4 = &s3;
_ = s4;
}
};
try S.doTheTest();
comptime try S.doTheTest();
}