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Fix #pragma (packed, n) not emitting the alignment in debug info #94673

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Merged
merged 1 commit into from
Jun 7, 2024
Merged

Fix #pragma (packed, n) not emitting the alignment in debug info #94673

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11 changes: 10 additions & 1 deletion clang/lib/CodeGen/CGDebugInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,16 @@ using namespace clang::CodeGen;

static uint32_t getTypeAlignIfRequired(const Type *Ty, const ASTContext &Ctx) {
auto TI = Ctx.getTypeInfo(Ty);
return TI.isAlignRequired() ? TI.Align : 0;
if (TI.isAlignRequired())
return TI.Align;

// MaxFieldAlignmentAttr is the attribute added to types
// declared after #pragma pack(n).
if (auto *Decl = Ty->getAsRecordDecl())
if (Decl->hasAttr<MaxFieldAlignmentAttr>())
return TI.Align;

return 0;
}

static uint32_t getTypeAlignIfRequired(QualType Ty, const ASTContext &Ctx) {
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4 changes: 2 additions & 2 deletions clang/test/CodeGen/debug-info-packed-struct.c
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Expand Up @@ -59,7 +59,7 @@ struct layout2 {
#pragma pack()
// CHECK: l2_ofs0
// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "l2_ofs1",
// CHECK-SAME: {{.*}}size: 64, offset: 8)
// CHECK-SAME: {{.*}}size: 64, align: 8, offset: 8)
// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "l2_ofs9",
// CHECK-SAME: {{.*}}size: 1, offset: 72, flags: DIFlagBitField, extraData: i64 72)

Expand All @@ -81,7 +81,7 @@ struct layout3 {
#pragma pack()
// CHECK: l3_ofs0
// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "l3_ofs4",
// CHECK-SAME: {{.*}}size: 64, offset: 32)
// CHECK-SAME: {{.*}}size: 64, align: 32, offset: 32)
// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "l3_ofs12",
// CHECK-SAME: {{.*}}size: 1, offset: 96, flags: DIFlagBitField, extraData: i64 96)

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8 changes: 8 additions & 0 deletions clang/test/CodeGenCXX/debug-info-struct-align.cpp
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Expand Up @@ -25,3 +25,11 @@ struct MyType2 {
MyType2 mt2;

static_assert(alignof(MyType2) == 1, "alignof MyType2 is wrong");

#pragma pack(1)
struct MyType3 {
int m;
};
MyType3 mt3;

static_assert(alignof(MyType3) == 1, "alignof MyType3 is wrong");