authorgravatar for jacobly@ziglang.orgJacob Young <jacobly@ziglang.org> 2026-04-25 11:59:21-04:00
committergravatar for jacobly@ziglang.orgJacob Young <jacobly@ziglang.org> 2026-04-25 12:10:35-04:00
log2040f9bfd0ab874c6b7a748b9293ad31c7392459
tree64d50a3c30c144ca9d9997d2a1378f07fc1f6b05
parentcb1c7319b575372009185c25eac7b29b93ae83f4

x86_64: fix c abi of `f32` struct field followed by padding

Closes #31864

4 files changed, 25 insertions(+), 29 deletions(-)

src/codegen/x86_64/CodeGen.zig+5-3
......@@ -181632,9 +181632,11 @@ fn splitType(self: *CodeGen, comptime parts_len: usize, ty: Type) ![parts_len]Ty
181632181632 else => break,
181633181633 };
181634181634 } else {
181635 var part_sizes: u64 = 0;
181636 for (parts) |part| part_sizes += part.abiSize(zcu);
181637 if (part_sizes == ty.abiSize(zcu)) return parts;
181635 var parts_size: u64 = 0;
181636 for (parts) |part| parts_size += part.abiSize(zcu);
181637 const abi_size = ty.abiSize(zcu);
181638 if (abi_size == parts_size) return parts;
181639 if (classes[classes.len - 1] == .float and abi_size > parts_size and abi_size <= parts_size + 4) return parts;
181638181640 };
181639181641 return self.fail("TODO implement splitType({d}, {f})", .{ parts_len, ty.fmt(pt) });
181640181642}
src/codegen/x86_64/abi.zig+13-8
......@@ -300,21 +300,26 @@ pub fn classifySystemV(ty: Type, zcu: *Zcu, target: *const std.Target, ctx: Cont
300300 for (result, 0..) |class, i| switch (class) {
301301 .memory => return Class.stack,
302302 .x87up => if (i == 0 or result[i - 1] != .x87) return Class.stack,
303 else => continue,
303 else => {},
304304 };
305305 // "If the size of the aggregate exceeds two eightbytes and the first eight-
306 // byte isn’t SSE or any other eightbyte isn’t SSEUP, the whole argument
306 // byte isn't SSE or any other eightbyte isn't SSEUP, the whole argument
307307 // is passed in memory."
308308 if (ty_size > 16 and (result[0] != .sse or
309309 std.mem.indexOfNone(Class, result[1..], &.{ .sseup, .none }) != null)) return Class.stack;
310310
311311 // "If SSEUP is not preceded by SSE or SSEUP, it is converted to SSE."
312 for (&result, 0..) |*item, i| {
313 if (item.* == .sseup) switch (result[i - 1]) {
314 .sse, .sseup => continue,
315 else => item.* = .sse,
316 };
317 }
312 for (&result, 0..) |*class, i| switch (class.*) {
313 .sseup => switch (result[i - 1]) {
314 .sse, .sseup => {},
315 else => class.* = .sse,
316 },
317 .float => if (i + 1 < result.len) switch (result[i + 1]) {
318 .none => {},
319 else => class.* = .float_combine,
320 },
321 else => {},
322 };
318323 return result;
319324 },
320325 .array => {
test/c_abi/cfuncs.c-2
......@@ -2948,7 +2948,6 @@ void run_c_tests(void) {
29482948#if !defined(__riscv)
29492949#if !defined(__s390x__)
29502950#if !defined(__i386__)
2951#if !defined(__x86_64__)
29522951 {
29532952 struct Struct_f32a8_f32a8 s = zig_ret_struct_f32a8_f32a8();
29542953 assert_or_panic(s.a == 1.25f);
......@@ -2962,7 +2961,6 @@ void run_c_tests(void) {
29622961#endif
29632962#endif
29642963#endif
2965#endif
29662964
29672965#if !(defined(__arm__) && defined(__SOFTFP__))
29682966#if !defined(__loongarch__) && !defined(__mips64__)
test/c_abi/main.zig+7-16
......@@ -554,22 +554,14 @@ const Struct_f32a8_f32a8 = extern struct {
554554 b: f32 align(8),
555555};
556556
557comptime {
558 skip: {
559 if (builtin.zig_backend == .stage2_x86_64) break :skip;
560
561 _ = struct {
562 export fn zig_ret_struct_f32a8_f32a8() Struct_f32a8_f32a8 {
563 return .{ .a = 1.25, .b = 2.75 };
564 }
557export fn zig_ret_struct_f32a8_f32a8() Struct_f32a8_f32a8 {
558 return .{ .a = 1.25, .b = 2.75 };
559}
565560
566 export fn zig_struct_f32a8_f32a8(s: Struct_f32a8_f32a8, f: f32) void {
567 expect(s.a == 3.125) catch @panic("test failure");
568 expect(s.b == 4.375) catch @panic("test failure");
569 expect(f == 5.5) catch @panic("test failure");
570 }
571 };
572 }
561export fn zig_struct_f32a8_f32a8(s: Struct_f32a8_f32a8, f: f32) void {
562 expect(s.a == 3.125) catch @panic("test failure");
563 expect(s.b == 4.375) catch @panic("test failure");
564 expect(f == 5.5) catch @panic("test failure");
573565}
574566
575567extern fn c_ret_struct_f32a8_f32a8() Struct_f32a8_f32a8;
......@@ -584,7 +576,6 @@ test "C ABI struct f32 align(8), f32 align(8)" {
584576 if (builtin.cpu.arch.isRISCV()) return error.SkipZigTest;
585577 if (builtin.cpu.arch == .s390x) return error.SkipZigTest;
586578 if (builtin.cpu.arch == .x86) return error.SkipZigTest;
587 if (builtin.cpu.arch == .x86_64) return error.SkipZigTest;
588579
589580 const s = c_ret_struct_f32a8_f32a8();
590581 try expect(s.a == 6.625);