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ahatanakahatanak
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[PAC] Fix codegen for polymorphic class variables with consteval constructors (#154858)
Fix a bug in CodeGen where such variables could cause a compilation error or be emitted with an undef initializer when the vtable was signed with address discrimination. rdar://155696134
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2 files changed

+33
-11
lines changed

2 files changed

+33
-11
lines changed

‎clang/lib/CodeGen/CGExprConstant.cpp

Lines changed: 4 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -876,8 +876,9 @@ bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD,
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877877
for (const BaseInfo &Base : Bases) {
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bool IsPrimaryBase = Layout.getPrimaryBase() == Base.Decl;
879-
Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
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VTableClass, Offset + Base.Offset);
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if (!Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
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VTableClass, Offset + Base.Offset))
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return false;
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}
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}
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@@ -1627,7 +1628,7 @@ llvm::Constant *ConstantEmitter::tryEmitConstantExpr(const ConstantExpr *CE) {
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if (CE->isGLValue())
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RetType = CGM.getContext().getLValueReferenceType(RetType);
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1630-
return emitAbstract(CE->getBeginLoc(), CE->getAPValueResult(), RetType);
1631+
return tryEmitAbstract(CE->getAPValueResult(), RetType);
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}
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llvm::Constant *

‎clang/test/CodeGenCXX/ptrauth-explicit-vtable-pointer-control.cpp

Lines changed: 29 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -1,31 +1,31 @@
1-
// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
1+
// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
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// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,NODISC %s
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4-
// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
4+
// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
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// RUN: -fptrauth-vtable-pointer-type-discrimination \
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// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,TYPE %s
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8-
// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
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// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
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// RUN: -fptrauth-vtable-pointer-address-discrimination \
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// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,ADDR %s
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12-
// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
12+
// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
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// RUN: -fptrauth-vtable-pointer-type-discrimination \
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// RUN: -fptrauth-vtable-pointer-address-discrimination \
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// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,BOTH %s
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17-
// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
17+
// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
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// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,NODISC %s
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20-
// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
20+
// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
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// RUN: -fptrauth-vtable-pointer-type-discrimination \
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// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,TYPE %s
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24-
// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
24+
// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
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// RUN: -fptrauth-vtable-pointer-address-discrimination \
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// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,ADDR %s
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28-
// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
28+
// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
2929
// RUN: -fptrauth-vtable-pointer-type-discrimination \
3030
// RUN: -fptrauth-vtable-pointer-address-discrimination \
3131
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,BOTH %s
@@ -78,6 +78,27 @@ struct authenticated(default_key, default_address_discrimination, custom_discrim
7878
virtual void g();
7979
};
8080

81+
// CHECK: @_ZTVN5test19ConstEvalE = external unnamed_addr constant { [3 x ptr] }, align 8
82+
// CHECK: @_ZN5test12ceE = global %{{.*}} { ptr ptrauth (ptr getelementptr inbounds inrange(-16, 8) ({ [3 x ptr] }, ptr @_ZTVN5test19ConstEvalE, i32 0, i32 0, i32 2), i32 2, i64 0, ptr @_ZN5test12ceE) }, align 8
83+
// CHECK: @_ZTVN5test116ConstEvalDerivedE = linkonce_odr unnamed_addr constant { [3 x ptr] } { [3 x ptr] [ptr null, ptr @_ZTIN5test116ConstEvalDerivedE, ptr ptrauth (ptr @_ZN5test19ConstEval1fEv, i32 0, i64 26259, ptr getelementptr inbounds ({ [3 x ptr] }, ptr @_ZTVN5test116ConstEvalDerivedE, i32 0, i32 0, i32 2))] },{{.*}}align 8
84+
// CHECK: @_ZN5test13cedE = global { ptr } { ptr ptrauth (ptr getelementptr inbounds inrange(-16, 8) ({ [3 x ptr] }, ptr @_ZTVN5test116ConstEvalDerivedE, i32 0, i32 0, i32 2), i32 2, i64 0, ptr @_ZN5test13cedE) }, align 8
85+
86+
struct authenticated(default_key, address_discrimination, no_extra_discrimination) ConstEval {
87+
consteval ConstEval() {}
88+
virtual void f();
89+
};
90+
91+
// clang used to bail out with error message "could not emit constant value abstractly".
92+
ConstEval ce;
93+
94+
struct ConstEvalDerived : public ConstEval {
95+
public:
96+
consteval ConstEvalDerived() {}
97+
};
98+
99+
// clang used to emit an undef initializer.
100+
ConstEvalDerived ced;
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81102
template <typename T>
82103
struct SubClass : T {
83104
virtual void g();

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