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Merged
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Apr 28, 2025
Merged

[HLSL] Treat classes and structs as packed by default #137391

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a799f61
[HLSL] Treat classes and structs as packed by default
bogner Apr 19, 2025
dfbb395
fixup: Move test
bogner Apr 28, 2025
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4 changes: 4 additions & 0 deletions clang/lib/Sema/SemaDecl.cpp
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Expand Up @@ -17567,6 +17567,8 @@ Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
// parsing of the struct).
if (TUK == TagUseKind::Definition &&
(!SkipBody || !SkipBody->ShouldSkip)) {
if (LangOpts.HLSL)
RD->addAttr(PackedAttr::CreateImplicit(Context));
AddAlignmentAttributesForRecord(RD);
AddMsStructLayoutForRecord(RD);
}
Expand Down Expand Up @@ -18257,6 +18259,8 @@ Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
// the #pragma tokens are effectively skipped over during the
// parsing of the struct).
if (TUK == TagUseKind::Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
if (LangOpts.HLSL)
RD->addAttr(PackedAttr::CreateImplicit(Context));
AddAlignmentAttributesForRecord(RD);
AddMsStructLayoutForRecord(RD);
}
Expand Down
4 changes: 4 additions & 0 deletions clang/lib/Sema/SemaTemplate.cpp
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Expand Up @@ -2116,6 +2116,8 @@ DeclResult Sema::CheckClassTemplate(
// Add alignment attributes if necessary; these attributes are checked when
// the ASTContext lays out the structure.
if (TUK == TagUseKind::Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
if (LangOpts.HLSL)
NewClass->addAttr(PackedAttr::CreateImplicit(Context));
AddAlignmentAttributesForRecord(NewClass);
AddMsStructLayoutForRecord(NewClass);
}
Expand Down Expand Up @@ -8655,6 +8657,8 @@ DeclResult Sema::ActOnClassTemplateSpecialization(
// Add alignment attributes if necessary; these attributes are checked when
// the ASTContext lays out the structure.
if (TUK == TagUseKind::Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
if (LangOpts.HLSL)
Specialization->addAttr(PackedAttr::CreateImplicit(Context));
AddAlignmentAttributesForRecord(Specialization);
AddMsStructLayoutForRecord(Specialization);
}
Expand Down
13 changes: 13 additions & 0 deletions clang/test/AST/HLSL/PackedStruct.hlsl
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@@ -0,0 +1,13 @@
// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -ast-dump %s | FileCheck %s
// Structs are packed by default in HLSL

#include <hlsl/hlsl_basic_types.h>

// CHECK: CXXRecordDecl {{.*}} struct S definition
// CHECK: DefinitionData
// CHECK: PackedAttr {{.*}} Implicit
// CHECK-NEXT: CXXRecordDecl {{.*}} implicit struct S
struct S {
float2 f;
int i;
};
6 changes: 3 additions & 3 deletions clang/test/CodeGenHLSL/ArrayAssignable.hlsl
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Expand Up @@ -10,7 +10,7 @@ struct S {
// CHECK: @c1 = external addrspace(2) global [2 x float], align 4
// CHECK: @c2 = external addrspace(2) global [2 x <4 x i32>], align 16
// CHECK: @c3 = external addrspace(2) global [2 x [2 x i32]], align 4
// CHECK: @c4 = external addrspace(2) global [1 x target("dx.Layout", %S, 8, 0, 4)], align 4
// CHECK: @c4 = external addrspace(2) global [1 x target("dx.Layout", %S, 8, 0, 4)], align 1

cbuffer CBArrays : register(b0) {
float c1[2];
Expand Down Expand Up @@ -169,8 +169,8 @@ void arr_assign10() {
}

// CHECK-LABEL: define void {{.*}}arr_assign11
// CHECK: [[C:%.*]] = alloca [1 x %struct.S], align 4
// CHECK: call void @llvm.memcpy.p0.p2.i32(ptr align 4 [[C]], ptr addrspace(2) align 4 @c4, i32 8, i1 false)
// CHECK: [[C:%.*]] = alloca [1 x %struct.S], align 1
// CHECK: call void @llvm.memcpy.p0.p2.i32(ptr align 1 [[C]], ptr addrspace(2) align 1 @c4, i32 8, i1 false)
// CHECK-NEXT: ret void
void arr_assign11() {
S s = {1, 2.0};
Expand Down
6 changes: 3 additions & 3 deletions clang/test/CodeGenHLSL/ArrayTemporary.hlsl
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Expand Up @@ -24,9 +24,9 @@ void fn2(Obj O[4]) { }
// CHECK-LABEL: define void {{.*}}call2{{.*}}
// CHECK: [[Arr:%.*]] = alloca [4 x %struct.Obj]
// CHECK: [[Tmp:%.*]] = alloca [4 x %struct.Obj]
// CHECK: call void @llvm.memset.p0.i32(ptr align 4 [[Arr]], i8 0, i32 32, i1 false)
// CHECK: call void @llvm.memcpy.p0.p0.i32(ptr align 4 [[Tmp]], ptr align 4 [[Arr]], i32 32, i1 false)
// CHECK: call void {{.*}}fn2{{.*}}(ptr noundef byval([4 x %struct.Obj]) align 4 [[Tmp]])
// CHECK: call void @llvm.memset.p0.i32(ptr align 1 [[Arr]], i8 0, i32 32, i1 false)
// CHECK: call void @llvm.memcpy.p0.p0.i32(ptr align 1 [[Tmp]], ptr align 1 [[Arr]], i32 32, i1 false)
// CHECK: call void {{.*}}fn2{{.*}}(ptr noundef byval([4 x %struct.Obj]) align 1 [[Tmp]])
void call2() {
Obj Arr[4] = {{0, 0}, {0, 0}, {0, 0}, {0, 0}};
fn2(Arr);
Expand Down
4 changes: 2 additions & 2 deletions clang/test/CodeGenHLSL/BasicFeatures/AggregateSplatCast.hlsl
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Expand Up @@ -55,7 +55,7 @@ struct S {
// struct splats
// CHECK-LABEL: define void {{.*}}call3
// CHECK: [[A:%.*]] = alloca <1 x i32>, align 4
// CHECK: [[s:%.*]] = alloca %struct.S, align 4
// CHECK: [[s:%.*]] = alloca %struct.S, align 1
// CHECK-NEXT: store <1 x i32> splat (i32 1), ptr [[A]], align 4
// CHECK-NEXT: [[L:%.*]] = load <1 x i32>, ptr [[A]], align 4
// CHECK-NEXT: [[VL:%.*]] = extractelement <1 x i32> [[L]], i32 0
Expand All @@ -72,7 +72,7 @@ export void call3() {
// struct splat from vector of length 1
// CHECK-LABEL: define void {{.*}}call5
// CHECK: [[A:%.*]] = alloca <1 x i32>, align 4
// CHECK-NEXT: [[s:%.*]] = alloca %struct.S, align 4
// CHECK-NEXT: [[s:%.*]] = alloca %struct.S, align 1
// CHECK-NEXT: store <1 x i32> splat (i32 1), ptr [[A]], align 4
// CHECK-NEXT: [[L:%.*]] = load <1 x i32>, ptr [[A]], align 4
// CHECK-NEXT: [[VL:%.*]] = extractelement <1 x i32> [[L]], i32 0
Expand Down
9 changes: 4 additions & 5 deletions clang/test/CodeGenHLSL/BasicFeatures/ArrayElementwiseCast.hlsl
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Expand Up @@ -125,12 +125,12 @@ struct S {

// flatten and truncate from a struct
// CHECK-LABEL: define void {{.*}}call7
// CHECK: [[s:%.*]] = alloca %struct.S, align 4
// CHECK: [[s:%.*]] = alloca %struct.S, align 1
// CHECK-NEXT: [[A:%.*]] = alloca [1 x i32], align 4
// CHECK-NEXT: [[Tmp:%.*]] = alloca %struct.S, align 4
// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 [[s]], ptr align 4 {{.*}}, i32 8, i1 false)
// CHECK-NEXT: [[Tmp:%.*]] = alloca %struct.S, align 1
// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 1 [[s]], ptr align 1 {{.*}}, i32 8, i1 false)
// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 [[A]], ptr align 4 {{.*}}, i32 4, i1 false)
// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 [[Tmp]], ptr align 4 [[s]], i32 8, i1 false)
// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 1 [[Tmp]], ptr align 1 [[s]], i32 8, i1 false)
// CHECK-NEXT: [[G1:%.*]] = getelementptr inbounds [1 x i32], ptr [[A]], i32 0, i32 0
// CHECK-NEXT: [[G2:%.*]] = getelementptr inbounds %struct.S, ptr [[Tmp]], i32 0, i32 0
// CHECK-NEXT: [[G3:%.*]] = getelementptr inbounds %struct.S, ptr [[Tmp]], i32 0, i32 1
Expand All @@ -141,4 +141,3 @@ export void call7() {
int A[1] = {1};
A = (int[1])s;
}

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