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Merged
merged 4 commits into from
Mar 13, 2024
Merged

Pick fixes for Unions & tbaa.struct #8375

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3cb8aeb
[TBAA] Add extra tests to copy structs with union members.
fhahn Mar 7, 2024
42853d0
[TBAA] Add test showing tbaa.struct being generated with relaxed-alias.
fhahn Mar 7, 2024
96bb057
[TBAA] Add bail-out to skip tbaa generation to getTBAAStructInfo. (#8…
fhahn Mar 8, 2024
890cbe9
[TBAA] Generate tbaa.struct single field with char tag for unions. (#…
fhahn Mar 11, 2024
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11 changes: 11 additions & 0 deletions clang/lib/CodeGen/CodeGenTBAA.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -283,6 +283,14 @@ CodeGenTBAA::CollectFields(uint64_t BaseOffset,
/* Things not handled yet include: C++ base classes, bitfields, */

if (const RecordType *TTy = QTy->getAs<RecordType>()) {
if (TTy->isUnionType()) {
uint64_t Size = Context.getTypeSizeInChars(QTy).getQuantity();
llvm::MDNode *TBAAType = getChar();
llvm::MDNode *TBAATag = getAccessTagInfo(TBAAAccessInfo(TBAAType, Size));
Fields.push_back(
llvm::MDBuilder::TBAAStructField(BaseOffset, Size, TBAATag));
return true;
}
const RecordDecl *RD = TTy->getDecl()->getDefinition();
if (RD->hasFlexibleArrayMember())
return false;
Expand Down Expand Up @@ -340,6 +348,9 @@ CodeGenTBAA::CollectFields(uint64_t BaseOffset,

llvm::MDNode *
CodeGenTBAA::getTBAAStructInfo(QualType QTy) {
if (CodeGenOpts.OptimizationLevel == 0 || CodeGenOpts.RelaxedAliasing)
return nullptr;

const Type *Ty = Context.getCanonicalType(QTy).getTypePtr();

if (llvm::MDNode *N = StructMetadataCache[Ty])
Expand Down
24 changes: 24 additions & 0 deletions clang/test/CodeGen/tbaa-struct-relaxed-aliasing-with-tsan.cpp
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@@ -0,0 +1,24 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin -emit-llvm -o - -O1 -relaxed-aliasing -fsanitize=thread -disable-llvm-optzns %s | \
// RUN: FileCheck %s
// RUN: %clang_cc1 -triple x86_64-apple-darwin -new-struct-path-tbaa \
// RUN: -emit-llvm -o - -O1 -relaxed-aliasing -fsanitize=thread -disable-llvm-optzns %s | \
// RUN: FileCheck %s
//
// Check that we do not create tbaa for instructions generated for copies.

// CHECK-NOT: !tbaa

struct A {
short s;
int i;
char c;
int j;
};

void copyStruct(A *a1, A *a2) {
*a1 = *a2;
}

void copyInt(int *a, int *b) {
*a = *b;
}
40 changes: 39 additions & 1 deletion clang/test/CodeGen/tbaa-struct.cpp
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Expand Up @@ -151,6 +151,38 @@ void copy10(NamedBitfields3 *a1, NamedBitfields3 *a2) {
*a1 = *a2;
}

union U2 {
double d;
float f;
};

struct UnionMember1 {
U2 u;
int p;
};

void copy11(UnionMember1 *a1, UnionMember1 *a2) {
// CHECK-LABEL: _Z6copy11P12UnionMember1S0_
// CHECK: tail call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 8 dereferenceable(16) %a1, ptr noundef nonnull align 8 dereferenceable(16) %a2, i64 16, i1 false),
// CHECK-OLD-SAME: !tbaa.struct [[TS9:!.*]]
// CHECK-NEW-SAME: !tbaa [[TAG_UnionMember1:!.+]], !tbaa.struct
*a1 = *a2;
}

struct UnionMember2 {
int p;
U2 u;
};

void copy12(UnionMember2 *a1, UnionMember2 *a2) {
// CHECK-LABEL: _Z6copy12P12UnionMember2S0_
// CHECK: tail call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 8 dereferenceable(16) %a1, ptr noundef nonnull align 8 dereferenceable(16) %a2, i64 16, i1 false),
// CHECK-OLD-SAME: !tbaa.struct [[TS10:!.*]]
// CHECK-NEW-SAME: !tbaa [[TAG_UnionMember2:!.+]], !tbaa.struct

*a1 = *a2;
}

// CHECK-OLD: [[TS]] = !{i64 0, i64 2, !{{.*}}, i64 4, i64 4, !{{.*}}, i64 8, i64 1, !{{.*}}, i64 12, i64 4, !{{.*}}}
// CHECK-OLD: [[CHAR:!.*]] = !{!"omnipotent char", !{{.*}}}
// CHECK-OLD: [[TAG_INT:!.*]] = !{[[INT:!.*]], [[INT]], i64 0}
Expand All @@ -159,14 +191,16 @@ void copy10(NamedBitfields3 *a1, NamedBitfields3 *a2) {
// (offset, size) = (0,1) char; (4,2) short; (8,4) int; (12,1) char; (16,4) int; (20,4) int
// CHECK-OLD: [[TS2]] = !{i64 0, i64 1, !{{.*}}, i64 4, i64 2, !{{.*}}, i64 8, i64 4, !{{.*}}, i64 12, i64 1, !{{.*}}, i64 16, i64 4, {{.*}}, i64 20, i64 4, {{.*}}}
// (offset, size) = (0,8) char; (0,2) char; (4,8) char
// CHECK-OLD: [[TS3]] = !{i64 0, i64 8, !{{.*}}, i64 0, i64 2, !{{.*}}, i64 4, i64 8, !{{.*}}}
// CHECK-OLD: [[TS3]] = !{i64 0, i64 12, [[TAG_CHAR]]}
// CHECK-OLD: [[TS4]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 1, i64 1, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]]}
// CHECK-OLD: [[TS5]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 4, i64 1, [[TAG_CHAR]], i64 5, i64 1, [[TAG_CHAR]]}
// CHECK-OLD: [[TS6]] = !{i64 0, i64 2, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE:!.+]]}
// CHECK-OLD: [[TAG_DOUBLE]] = !{[[DOUBLE:!.+]], [[DOUBLE]], i64 0}
// CHECK-OLD [[DOUBLE]] = !{!"double", [[CHAR]], i64 0}
// CHECK-OLD: [[TS7]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 1, i64 1, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]], i64 3, i64 1, [[TAG_CHAR]], i64 4, i64 1, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE]], i64 16, i64 1, [[TAG_CHAR]]}
// CHECK-OLD: [[TS8]] = !{i64 0, i64 4, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE]]}
// CHECK-OLD: [[TS9]] = !{i64 0, i64 8, [[TAG_CHAR]], i64 8, i64 4, [[TAG_INT]]}
// CHECK-OLD: [[TS10]] = !{i64 0, i64 4, [[TAG_INT]], i64 8, i64 8, [[TAG_CHAR]]}

// CHECK-NEW-DAG: [[TYPE_char:!.*]] = !{{{.*}}, i64 1, !"omnipotent char"}
// CHECK-NEW-DAG: [[TAG_char]] = !{[[TYPE_char]], [[TYPE_char]], i64 0, i64 0}
Expand All @@ -188,3 +222,7 @@ void copy10(NamedBitfields3 *a1, NamedBitfields3 *a2) {
// CHECK-NEW-DAG: [[TYPE_NamedBitfields2]] = !{[[TYPE_char]], i64 24, !"_ZTS15NamedBitfields2", [[TYPE_char]], i64 0, i64 1, [[TYPE_char]], i64 1, i64 1, [[TYPE_char]], i64 2, i64 1, [[TYPE_int]], i64 3, i64 4, [[TYPE_int]], i64 3, i64 4, [[TYPE_char]], i64 4, i64 1, [[TYPE_double]], i64 8, i64 8, [[TYPE_int]], i64 16, i64 4}
// CHECK-NEW-DAG: [[TAG_NamedBitfields3]] = !{[[TYPE_NamedBitfields3:!.+]], [[TYPE_NamedBitfields3]], i64 0, i64 16}
// CHECK-NEW-DAG: [[TYPE_NamedBitfields3]] = !{[[TYPE_char]], i64 16, !"_ZTS15NamedBitfields3", [[TYPE_int]], i64 1, i64 4, [[TYPE_int]], i64 2, i64 4, [[TYPE_double]], i64 8, i64 8}
// CHECK-NEW-DAG: [[TAG_UnionMember1]] = !{[[TYPE_UnionMember1:!.+]], [[TYPE_UnionMember1]], i64 0, i64 16}
// CHECK-NEW-DAG: [[TYPE_UnionMember1]] = !{[[TYPE_char]], i64 16, !"_ZTS12UnionMember1", [[TYPE_char]], i64 0, i64 8, [[TYPE_int]], i64 8, i64 4}
// CHECK-NEW-DAG: [[TAG_UnionMember2]] = !{[[TYPE_UnionMember2:!.+]], [[TYPE_UnionMember2]], i64 0, i64 16}
// CHECK-NEW-DAG: [[TYPE_UnionMember2]] = !{[[TYPE_char]], i64 16, !"_ZTS12UnionMember2", [[TYPE_int]], i64 0, i64 4, [[TYPE_char]], i64 8, i64 8}