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[TBAA] Extend pointer TBAA to pointers of non-builtin types.
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Extend the logic added in 123c036
(#76612) to support pointers to
non-builtin types by using the mangled name of the canonical type.
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@fhahn
fhahn committed Oct 19, 2024
1 parent dde26e3 commit fcadf4d
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Showing 3 changed files with 61 additions and 23 deletions.
16 changes: 11 additions & 5 deletions clang/lib/CodeGen/CodeGenTBAA.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -221,21 +221,27 @@ llvm::MDNode *CodeGenTBAA::getTypeInfoHelper(const Type *Ty) {
PtrDepth++;
Ty = Ty->getPointeeType().getTypePtr();
} while (Ty->isPointerType());
// TODO: Implement C++'s type "similarity" and consider dis-"similar"
// pointers distinct for non-builtin types.

SmallString<256> TyName;
if (isa<BuiltinType>(Ty)) {
llvm::MDNode *ScalarMD = getTypeInfoHelper(Ty);
StringRef Name =
cast<llvm::MDString>(
ScalarMD->getOperand(CodeGenOpts.NewStructPathTBAA ? 2 : 0))
->getString();
TyName = Name;
} else if (!isa<VariableArrayType>(Ty)) {
// For non-builtin types use the mangled name of the canonical type.
llvm::raw_svector_ostream TyOut(TyName);
Context.createMangleContext()->mangleCanonicalTypeName(QualType(Ty, 0),
TyOut);
}

SmallString<256> OutName("p");
OutName += std::to_string(PtrDepth);
OutName += " ";
OutName += Name;
OutName += TyName;
return createScalarTypeNode(OutName, AnyPtr, Size);
}
return AnyPtr;
}

// Accesses to arrays are accesses to objects of their element types.
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38 changes: 27 additions & 11 deletions clang/test/CodeGen/tbaa-pointers.c
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Original file line number Diff line number Diff line change
Expand Up @@ -116,10 +116,12 @@ void p2struct(struct S1 **ptr) {
// COMMON-LABEL: define void @p2struct(
// COMMON-SAME: ptr noundef [[PTR:%.+]])
// COMMON: [[PTR_ADDR:%.+]] = alloca ptr, align 8
// ENABLED-NEXT: store ptr [[PTR]], ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR:!.+]]
// ENABLED-NEXT: store ptr [[PTR]], ptr [[PTR_ADDR]], align 8, !tbaa [[P2S1_TAG:!.+]]
// DEFAULT-NEXT: store ptr [[PTR]], ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR]]
// COMMON-NEXT: [[BASE:%.+]] = load ptr, ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR]]
// COMMON-NEXT: store ptr null, ptr [[BASE]], align 8, !tbaa [[ANYPTR]]
// ENABLED-NEXT: [[BASE:%.+]] = load ptr, ptr [[PTR_ADDR]], align 8, !tbaa [[P2S1_TAG]]
// DEFAULT-NEXT: [[BASE:%.+]] = load ptr, ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR]]
// ENABLED-NEXT: store ptr null, ptr [[BASE]], align 8, !tbaa [[P1S1_TAG:!.+]]
// DEFAULT-NEXT: store ptr null, ptr [[BASE]], align 8, !tbaa [[ANYPTR]]
// COMMON-NEXT: ret void
//
*ptr = 0;
Expand All @@ -129,9 +131,10 @@ void p2struct_const(struct S1 const **ptr) {
// COMMON-LABEL: define void @p2struct_const(
// COMMON-SAME: ptr noundef [[PTR:%.+]])
// COMMON: [[PTR_ADDR:%.+]] = alloca ptr, align 8
// COMMON-NEXT: store ptr [[PTR]], ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR]]
// COMMON-NEXT: store ptr [[PTR]], ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR:!.+]]
// COMMON-NEXT: [[BASE:%.+]] = load ptr, ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR]]
// COMMON-NEXT: store ptr null, ptr [[BASE]], align 8, !tbaa [[ANYPTR]]
// ENABLED-NEXT: store ptr null, ptr [[BASE]], align 8, !tbaa [[P1S1_TAG]]
// DEFAULT-NEXT: store ptr null, ptr [[BASE]], align 8, !tbaa [[ANYPTR]]
// COMMON-NEXT: ret void
//
*ptr = 0;
Expand All @@ -145,10 +148,14 @@ void p2struct2(struct S2 *ptr) {
// COMMON-LABEL: define void @p2struct2(
// COMMON-SAME: ptr noundef [[PTR:%.+]])
// COMMON: [[PTR_ADDR:%.+]] = alloca ptr, align 8
// COMMON-NEXT: store ptr [[PTR]], ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR]]
// COMMON-NEXT: [[BASE:%.+]] = load ptr, ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR]]
// COMMON-NEXT: [[S:%.+]] = getelementptr inbounds nuw %struct.S2, ptr [[BASE]], i32 0, i32 0
// COMMON-NEXT: store ptr null, ptr [[S]], align 8, !tbaa [[S2_S_TAG:!.+]]
// ENABLED-NEXT: store ptr [[PTR]], ptr [[PTR_ADDR]], align 8, !tbaa [[P1S2_TAG:!.+]]
// ENABLED-NEXT: [[BASE:%.+]] = load ptr, ptr [[PTR_ADDR]], align 8, !tbaa [[P1S2_TAG]]
// ENABLED-NEXT: [[S:%.+]] = getelementptr inbounds nuw %struct.S2, ptr [[BASE]], i32 0, i32 0
// ENABLED-NEXT: store ptr null, ptr [[S]], align 8, !tbaa [[S2_S_TAG:!.+]]
// DEFAULT-NEXT: store ptr [[PTR]], ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR]]
// DEFAULT-NEXT: [[BASE:%.+]] = load ptr, ptr [[PTR_ADDR]], align 8, !tbaa [[ANYPTR]]
// DEFAULT-NEXT: [[S:%.+]] = getelementptr inbounds nuw %struct.S2, ptr [[BASE]], i32 0, i32 0
// DEFAULT-NEXT: store ptr null, ptr [[S]], align 8, !tbaa [[S2_S_TAG:!.+]]
// COMMON-NEXT: ret void
ptr->s = 0;
}
Expand All @@ -171,5 +178,14 @@ void p2struct2(struct S2 *ptr) {
// ENABLED: [[P2CHAR]] = !{!"p2 omnipotent char", [[ANY_POINTER]], i64 0}
// ENABLED: [[P1CHAR_0]] = !{[[P1CHAR:!.+]], [[P1CHAR]], i64 0}
// ENABLED: [[P1CHAR]] = !{!"p1 omnipotent char", [[ANY_POINTER]], i64 0}
// COMMON: [[S2_S_TAG]] = !{[[S2_TY:!.+]], [[ANY_POINTER]], i64 0}
// COMMON: [[S2_TY]] = !{!"S2", [[ANY_POINTER]], i64 0}
// ENABLED: [[P2S1_TAG]] = !{[[P2S1:!.+]], [[P2S1]], i64 0}
// ENABLED: [[P2S1]] = !{!"p2 _ZTS2S1", [[ANY_POINTER]], i64 0}
// ENABLED: [[P1S1_TAG:!.+]] = !{[[P1S1:!.+]], [[P1S1]], i64 0}
// ENABLED: [[P1S1]] = !{!"p1 _ZTS2S1", [[ANY_POINTER]], i64 0}
// ENABLED: [[P1S2_TAG]] = !{[[P1S2:!.+]], [[P1S2]], i64 0}
// ENABLED: [[P1S2]] = !{!"p1 _ZTS2S2", [[ANY_POINTER]], i64 0}

// ENABLED: [[S2_S_TAG]] = !{[[S2_TY:!.+]], [[P1S1]], i64 0}
// ENABLED: [[S2_TY]] = !{!"S2", [[P1S1]], i64 0}
// DEFAULT: [[S2_S_TAG]] = !{[[S2_TY:!.+]], [[ANY_POINTER]], i64 0}
// DEFAULT: [[S2_TY]] = !{!"S2", [[ANY_POINTER]], i64 0}
30 changes: 23 additions & 7 deletions clang/test/CodeGen/tbaa-reference.cpp
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
// RUN: %clang_cc1 -triple x86_64-linux -O1 -disable-llvm-passes %s -emit-llvm -o - | FileCheck %s -check-prefixes=CHECK,OLD-PATH
// RUN: %clang_cc1 -triple x86_64-linux -O1 -disable-llvm-passes -pointer-tbaa %s -emit-llvm -o - | FileCheck %s -check-prefixes=CHECK,OLD-PATH
// RUN: %clang_cc1 -triple x86_64-linux -O1 -disable-llvm-passes -pointer-tbaa %s -emit-llvm -o - | FileCheck %s -check-prefixes=CHECK,OLD-PATH-POINTER
// RUN: %clang_cc1 -triple x86_64-linux -O1 -disable-llvm-passes %s -emit-llvm -new-struct-path-tbaa -o - | FileCheck %s -check-prefixes=CHECK,NEW-PATH
// RUN: %clang_cc1 -triple x86_64-linux -O1 -disable-llvm-passes %s -pointer-tbaa -emit-llvm -new-struct-path-tbaa -o - | FileCheck %s -check-prefixes=CHECK,NEW-PATH
// RUN: %clang_cc1 -triple x86_64-linux -O1 -disable-llvm-passes %s -pointer-tbaa -emit-llvm -new-struct-path-tbaa -o - | FileCheck %s -check-prefixes=CHECK,NEW-PATH-POINTER
//
// Check that we generate correct TBAA information for reference accesses.

Expand All @@ -16,13 +16,13 @@ struct B {
B::B(S &s) : s(s) {
// CHECK-LABEL: _ZN1BC2ER1S
// Check initialization of the reference parameter.
// CHECK: store ptr {{.*}}, ptr {{.*}}, !tbaa [[TAG_pointer:!.*]]
// CHECK: store ptr {{.*}}, ptr %s.addr, align 8, !tbaa [[TAG_S_PTR:!.*]]

// Check loading of the reference parameter.
// CHECK: load ptr, ptr {{.*}}, !tbaa [[TAG_pointer]]
// CHECK: load ptr, ptr {{.*}}, !tbaa [[TAG_S_PTR:!.*]]

// Check initialization of the reference member.
// CHECK: store ptr {{.*}}, ptr {{.*}}, !tbaa [[TAG_pointer]]
// CHECK: store ptr {{.*}}, ptr {{.*}}, !tbaa [[TAG_S_PTR]]
}

S &B::get() {
Expand All @@ -32,16 +32,32 @@ S &B::get() {
return s;
}

// OLD-PATH-DAG: [[TAG_pointer]] = !{[[TYPE_pointer:!.*]], [[TYPE_pointer]], i64 0}
// OLD-PATH-DAG: [[TAG_S_PTR]] = !{[[TYPE_pointer:!.*]], [[TYPE_pointer]], i64 0}
// OLD-PATH-DAG: [[TAG_B_s]] = !{[[TYPE_B:!.*]], [[TYPE_pointer]], i64 0}
//
// OLD-PATH-DAG: [[TYPE_B]] = !{!"_ZTS1B", [[TYPE_pointer]], i64 0}
// OLD-PATH-DAG: [[TYPE_pointer]] = !{!"any pointer", [[TYPE_char:!.*]], i64 0}
// OLD-PATH-DAG: [[TYPE_char]] = !{!"omnipotent char", {{!.*}}, i64 0}

// NEW-PATH-DAG: [[TAG_pointer]] = !{[[TYPE_pointer:!.*]], [[TYPE_pointer]], i64 0, i64 8}
// OLD-PATH-POINTER-DAG: [[TAG_S_PTR]] = !{[[TYPE_S_PTR:!.*]], [[TYPE_S_PTR]], i64 0}
// OLD-PATH-POINTER-DAG: [[TAG_B_s]] = !{[[TYPE_B:!.*]], [[TYPE_S_PTR:!.*]], i64 0}
//
// OLD-PATH-POINTER-DAG: [[TYPE_B]] = !{!"_ZTS1B", [[TYPE_S_PTR:!.*]], i64 0}
// OLD-PATH-POINTER-DAG: [[TYPE_pointer:!.*]] = !{!"any pointer", [[TYPE_char:!.*]], i64 0}
// OLD-PATH-POINTER-DAG: [[TYPE_char]] = !{!"omnipotent char", {{!.*}}, i64 0}
// OLD-PATH-POINTER-DAG: [[TYPE_S_PTR]] = !{!"p1 _ZTS1S", [[TYPE_pointer]], i64 0}

// NEW-PATH-DAG: [[TAG_S_PTR]] = !{[[TYPE_pointer:!.*]], [[TYPE_pointer]], i64 0, i64 8}
// NEW-PATH-DAG: [[TAG_B_s]] = !{[[TYPE_B:!.*]], [[TYPE_pointer]], i64 0, i64 8}
//
// NEW-PATH-DAG: [[TYPE_B]] = !{[[TYPE_char:!.*]], i64 8, !"_ZTS1B", [[TYPE_pointer]], i64 0, i64 8}
// NEW-PATH-DAG: [[TYPE_pointer]] = !{[[TYPE_char:!.*]], i64 8, !"any pointer"}
// NEW-PATH-DAG: [[TYPE_char]] = !{{{!.*}}, i64 1, !"omnipotent char"}

// NEW-PATH-POINTER-DAG: [[TAG_S_PTR]] = !{[[TYPE_S_PTR:!.*]], [[TYPE_S_PTR]], i64 0, i64 8}
// NEW-PATH-POINTER-DAG: [[TAG_B_s]] = !{[[TYPE_B:!.*]], [[TYPE_S_PTR]], i64 0, i64 8}
//
// NEW-PATH-POINTER-DAG: [[TYPE_B]] = !{[[TYPE_char:!.*]], i64 8, !"_ZTS1B", [[TYPE_S_PTR]], i64 0, i64 8}
// NEW-PATH-POINTER-DAG: [[TYPE_S_PTR]] = !{[[TYPE_pointer:!.+]], i64 8, !"p1 _ZTS1S"}
// NEW-PATH-POINTER-DAG: [[TYPE_pointer]] = !{[[TYPE_char:!.*]], i64 8, !"any pointer"}
// NEW-PATH-POINTER-DAG: [[TYPE_char]] = !{{{!.*}}, i64 1, !"omnipotent char"}

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