authorgravatar for xavierb@gmail.comXavier Bouchoux <xavierb@gmail.com> 2023-07-29 11:50:25+02:00
committergravatar for xavierb@gmail.comXavier Bouchoux <xavierb@gmail.com> 2023-07-29 18:16:13+02:00
log8c367ef99aae05ddba800a6c01cb07677e2f512c
treea9fecf3efe8e4ed6285f4de7d11ad02edb86e3d1
parent46abf2045476a32b6f4dd939679c0fbc7a639133

codegen: fix access to byte-aligned nested packed struct elems

When acessing a packed struct member via a byte aligned ptr (from the optimisation in Sema.structFieldPtrByIndex()) the codegen must apply the parent ptr packed_offset in addition to the field offset itself. resolves https://github.com/ziglang/zig/issues/16609

5 files changed, 115 insertions(+), 12 deletions(-)

src/arch/wasm/CodeGen.zig+10-5
......@@ -3675,8 +3675,9 @@ fn airStructFieldPtr(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
36753675 const extra = func.air.extraData(Air.StructField, ty_pl.payload);
36763676
36773677 const struct_ptr = try func.resolveInst(extra.data.struct_operand);
3678 const struct_ty = func.typeOf(extra.data.struct_operand).childType(mod);
3679 const result = try func.structFieldPtr(inst, extra.data.struct_operand, struct_ptr, struct_ty, extra.data.field_index);
3678 const struct_ptr_ty = func.typeOf(extra.data.struct_operand);
3679 const struct_ty = struct_ptr_ty.childType(mod);
3680 const result = try func.structFieldPtr(inst, extra.data.struct_operand, struct_ptr, struct_ptr_ty, struct_ty, extra.data.field_index);
36803681 func.finishAir(inst, result, &.{extra.data.struct_operand});
36813682}
36823683
......@@ -3684,9 +3685,10 @@ fn airStructFieldPtrIndex(func: *CodeGen, inst: Air.Inst.Index, index: u32) Inne
36843685 const mod = func.bin_file.base.options.module.?;
36853686 const ty_op = func.air.instructions.items(.data)[inst].ty_op;
36863687 const struct_ptr = try func.resolveInst(ty_op.operand);
3687 const struct_ty = func.typeOf(ty_op.operand).childType(mod);
3688 const struct_ptr_ty = func.typeOf(ty_op.operand);
3689 const struct_ty = struct_ptr_ty.childType(mod);
36883690
3689 const result = try func.structFieldPtr(inst, ty_op.operand, struct_ptr, struct_ty, index);
3691 const result = try func.structFieldPtr(inst, ty_op.operand, struct_ptr, struct_ptr_ty, struct_ty, index);
36903692 func.finishAir(inst, result, &.{ty_op.operand});
36913693}
36923694
......@@ -3695,18 +3697,21 @@ fn structFieldPtr(
36953697 inst: Air.Inst.Index,
36963698 ref: Air.Inst.Ref,
36973699 struct_ptr: WValue,
3700 struct_ptr_ty: Type,
36983701 struct_ty: Type,
36993702 index: u32,
37003703) InnerError!WValue {
37013704 const mod = func.bin_file.base.options.module.?;
37023705 const result_ty = func.typeOfIndex(inst);
3706 const struct_ptr_ty_info = struct_ptr_ty.ptrInfo(mod);
3707
37033708 const offset = switch (struct_ty.containerLayout(mod)) {
37043709 .Packed => switch (struct_ty.zigTypeTag(mod)) {
37053710 .Struct => offset: {
37063711 if (result_ty.ptrInfo(mod).packed_offset.host_size != 0) {
37073712 break :offset @as(u32, 0);
37083713 }
3709 break :offset struct_ty.packedStructFieldByteOffset(index, mod);
3714 break :offset struct_ty.packedStructFieldByteOffset(index, mod) + @divExact(struct_ptr_ty_info.packed_offset.bit_offset, 8);
37103715 },
37113716 .Union => 0,
37123717 else => unreachable,
src/arch/x86_64/CodeGen.zig+3-1
......@@ -5556,12 +5556,14 @@ fn fieldPtr(self: *Self, inst: Air.Inst.Index, operand: Air.Inst.Ref, index: u32
55565556 const mod = self.bin_file.options.module.?;
55575557 const ptr_field_ty = self.typeOfIndex(inst);
55585558 const ptr_container_ty = self.typeOf(operand);
5559 const ptr_container_ty_info = ptr_container_ty.ptrInfo(mod);
55595560 const container_ty = ptr_container_ty.childType(mod);
5561
55605562 const field_offset: i32 = @intCast(switch (container_ty.containerLayout(mod)) {
55615563 .Auto, .Extern => container_ty.structFieldOffset(index, mod),
55625564 .Packed => if (container_ty.zigTypeTag(mod) == .Struct and
55635565 ptr_field_ty.ptrInfo(mod).packed_offset.host_size == 0)
5564 container_ty.packedStructFieldByteOffset(index, mod)
5566 container_ty.packedStructFieldByteOffset(index, mod) + @divExact(ptr_container_ty_info.packed_offset.bit_offset, 8)
55655567 else
55665568 0,
55675569 });
src/codegen/c.zig+6-5
......@@ -661,7 +661,7 @@ pub const DeclGen = struct {
661661 try dg.renderCType(writer, ptr_cty);
662662 try writer.writeByte(')');
663663 }
664 switch (fieldLocation(base_ty, ptr_ty, @as(u32, @intCast(field.index)), mod)) {
664 switch (fieldLocation(ptr_base_ty, ptr_ty, @as(u32, @intCast(field.index)), mod)) {
665665 .begin => try dg.renderParentPtr(writer, field.base, location),
666666 .field => |name| {
667667 try writer.writeAll("&(");
......@@ -5187,7 +5187,7 @@ fn airOptionalPayloadPtrSet(f: *Function, inst: Air.Inst.Index) !CValue {
51875187}
51885188
51895189fn fieldLocation(
5190 container_ty: Type,
5190 container_ptr_ty: Type,
51915191 field_ptr_ty: Type,
51925192 field_index: u32,
51935193 mod: *Module,
......@@ -5198,6 +5198,7 @@ fn fieldLocation(
51985198 end: void,
51995199} {
52005200 const ip = &mod.intern_pool;
5201 const container_ty = container_ptr_ty.childType(mod);
52015202 return switch (container_ty.zigTypeTag(mod)) {
52025203 .Struct => switch (container_ty.containerLayout(mod)) {
52035204 .Auto, .Extern => for (field_index..container_ty.structFieldCount(mod)) |next_field_index| {
......@@ -5211,7 +5212,7 @@ fn fieldLocation(
52115212 .{ .identifier = ip.stringToSlice(container_ty.structFieldName(next_field_index, mod)) } };
52125213 } else if (container_ty.hasRuntimeBitsIgnoreComptime(mod)) .end else .begin,
52135214 .Packed => if (field_ptr_ty.ptrInfo(mod).packed_offset.host_size == 0)
5214 .{ .byte_offset = container_ty.packedStructFieldByteOffset(field_index, mod) }
5215 .{ .byte_offset = container_ty.packedStructFieldByteOffset(field_index, mod) + @divExact(container_ptr_ty.ptrInfo(mod).packed_offset.bit_offset, 8) }
52155216 else
52165217 .begin,
52175218 },
......@@ -5282,7 +5283,7 @@ fn airFieldParentPtr(f: *Function, inst: Air.Inst.Index) !CValue {
52825283 try f.renderType(writer, container_ptr_ty);
52835284 try writer.writeByte(')');
52845285
5285 switch (fieldLocation(container_ty, field_ptr_ty, extra.field_index, mod)) {
5286 switch (fieldLocation(container_ptr_ty, field_ptr_ty, extra.field_index, mod)) {
52865287 .begin => try f.writeCValue(writer, field_ptr_val, .Initializer),
52875288 .field => |field| {
52885289 const u8_ptr_ty = try mod.adjustPtrTypeChild(field_ptr_ty, Type.u8);
......@@ -5339,7 +5340,7 @@ fn fieldPtr(
53395340 try f.renderType(writer, field_ptr_ty);
53405341 try writer.writeByte(')');
53415342
5342 switch (fieldLocation(container_ty, field_ptr_ty, field_index, mod)) {
5343 switch (fieldLocation(container_ptr_ty, field_ptr_ty, field_index, mod)) {
53435344 .begin => try f.writeCValue(writer, container_ptr_val, .Initializer),
53445345 .field => |field| {
53455346 try writer.writeByte('&');
src/codegen/llvm.zig+2-1
......@@ -10611,6 +10611,7 @@ pub const FuncGen = struct {
1061110611 .Packed => {
1061210612 const result_ty = self.typeOfIndex(inst);
1061310613 const result_ty_info = result_ty.ptrInfo(mod);
10614 const struct_ptr_ty_info = struct_ptr_ty.ptrInfo(mod);
1061410615
1061510616 if (result_ty_info.packed_offset.host_size != 0) {
1061610617 // From LLVM's perspective, a pointer to a packed struct and a pointer
......@@ -10622,7 +10623,7 @@ pub const FuncGen = struct {
1062210623
1062310624 // We have a pointer to a packed struct field that happens to be byte-aligned.
1062410625 // Offset our operand pointer by the correct number of bytes.
10625 const byte_offset = struct_ty.packedStructFieldByteOffset(field_index, mod);
10626 const byte_offset = struct_ty.packedStructFieldByteOffset(field_index, mod) + @divExact(struct_ptr_ty_info.packed_offset.bit_offset, 8);
1062610627 if (byte_offset == 0) return struct_ptr;
1062710628 const usize_ty = try o.lowerType(Type.usize);
1062810629 const llvm_index = try o.builder.intValue(usize_ty, byte_offset);
test/behavior/packed-struct.zig+94
......@@ -528,6 +528,100 @@ test "nested packed struct field access test" {
528528 try std.testing.expect(arg.g.i == 8);
529529}
530530
531test "nested packed struct at non-zero offset" {
532 if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
533 if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
534
535 const Pair = packed struct(u24) {
536 a: u16 = 0,
537 b: u8 = 0,
538 };
539 const A = packed struct {
540 p1: Pair,
541 p2: Pair,
542 };
543
544 var k: u8 = 123;
545 var v: A = .{
546 .p1 = .{ .a = k + 1, .b = k },
547 .p2 = .{ .a = k + 1, .b = k },
548 };
549
550 try expect(v.p1.a == k + 1 and v.p1.b == k);
551 try expect(v.p2.a == k + 1 and v.p2.b == k);
552
553 v.p2.a -= v.p1.a;
554 v.p2.b -= v.p1.b;
555 try expect(v.p2.a == 0 and v.p2.b == 0);
556 try expect(v.p1.a == k + 1 and v.p1.b == k);
557}
558
559test "nested packed struct at non-zero offset 2" {
560 if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
561 if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
562 if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
563 if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
564 if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
565 if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
566 if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
567
568 const S = struct {
569 const Pair = packed struct(u40) {
570 a: u32 = 0,
571 b: u8 = 0,
572 };
573 const A = packed struct {
574 p1: Pair,
575 p2: Pair,
576 c: C,
577 };
578 const C = packed struct {
579 p1: Pair,
580 pad1: u5,
581 p2: Pair,
582 pad2: u3,
583 last: i16,
584 };
585
586 fn doTheTest() !void {
587 var k: u8 = 123;
588 var v: A = .{
589 .p1 = .{ .a = k + 1, .b = k },
590 .p2 = .{ .a = k + 1, .b = k },
591 .c = .{
592 .pad1 = 11,
593 .pad2 = 2,
594 .p1 = .{ .a = k + 1, .b = k },
595 .p2 = .{ .a = k + 1, .b = k },
596 .last = -12345,
597 },
598 };
599
600 try expect(v.p1.a == k + 1 and v.p1.b == k);
601 try expect(v.p2.a == k + 1 and v.p2.b == k);
602 try expect(v.c.p2.a == k + 1 and v.c.p2.b == k);
603 try expect(v.c.p2.a == k + 1 and v.c.p2.b == k);
604 try expect(v.c.last == -12345);
605 try expect(v.c.pad1 == 11 and v.c.pad2 == 2);
606
607 v.p2.a -= v.p1.a;
608 v.p2.b -= v.p1.b;
609 v.c.p2.a -= v.c.p1.a;
610 v.c.p2.b -= v.c.p1.b;
611 v.c.last -|= 32000;
612 try expect(v.p2.a == 0 and v.p2.b == 0);
613 try expect(v.p1.a == k + 1 and v.p1.b == k);
614 try expect(v.c.p2.a == 0 and v.c.p2.b == 0);
615 try expect(v.c.p1.a == k + 1 and v.c.p1.b == k);
616 try expect(v.c.last == -32768);
617 try expect(v.c.pad1 == 11 and v.c.pad2 == 2);
618 }
619 };
620
621 try S.doTheTest();
622 try comptime S.doTheTest();
623}
624
531625test "runtime init of unnamed packed struct type" {
532626 if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
533627 if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;