[llvm-branch-commits] [clang] [PAC] Fix codegen for polymorphic class variables with consteval constructors (PR #155036)
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Fri Aug 22 14:50:08 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-codegen
Author: Akira Hatanaka (ahatanak)
<details>
<summary>Changes</summary>
Fix a bug in CodeGen where such variables could cause a compilation error or be emitted with an undef initializer.
rdar://155696134
---
Full diff: https://github.com/llvm/llvm-project/pull/155036.diff
2 Files Affected:
- (modified) clang/lib/CodeGen/CGExprConstant.cpp (+4-3)
- (modified) clang/test/CodeGenCXX/ptrauth-explicit-vtable-pointer-control.cpp (+29-8)
``````````diff
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 715bd392f59f7..0cc468ca3ab7e 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -873,8 +873,9 @@ bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD,
for (const BaseInfo &Base : Bases) {
bool IsPrimaryBase = Layout.getPrimaryBase() == Base.Decl;
- Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
- VTableClass, Offset + Base.Offset);
+ if (!Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
+ VTableClass, Offset + Base.Offset))
+ return false;
}
}
@@ -1620,7 +1621,7 @@ llvm::Constant *ConstantEmitter::tryEmitConstantExpr(const ConstantExpr *CE) {
if (CE->isGLValue())
RetType = CGM.getContext().getLValueReferenceType(RetType);
- return emitAbstract(CE->getBeginLoc(), CE->getAPValueResult(), RetType);
+ return tryEmitAbstract(CE->getAPValueResult(), RetType);
}
llvm::Constant *
diff --git a/clang/test/CodeGenCXX/ptrauth-explicit-vtable-pointer-control.cpp b/clang/test/CodeGenCXX/ptrauth-explicit-vtable-pointer-control.cpp
index 1b103719fbe46..e33525c1ec0f9 100644
--- a/clang/test/CodeGenCXX/ptrauth-explicit-vtable-pointer-control.cpp
+++ b/clang/test/CodeGenCXX/ptrauth-explicit-vtable-pointer-control.cpp
@@ -1,31 +1,31 @@
-// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
+// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,NODISC %s
-// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
+// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
// RUN: -fptrauth-vtable-pointer-type-discrimination \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,TYPE %s
-// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
+// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
// RUN: -fptrauth-vtable-pointer-address-discrimination \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,ADDR %s
-// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
+// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics \
// RUN: -fptrauth-vtable-pointer-type-discrimination \
// RUN: -fptrauth-vtable-pointer-address-discrimination \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,BOTH %s
-// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
+// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,NODISC %s
-// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
+// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
// RUN: -fptrauth-vtable-pointer-type-discrimination \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,TYPE %s
-// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
+// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
// RUN: -fptrauth-vtable-pointer-address-discrimination \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,ADDR %s
-// RUN: %clang_cc1 %s -x c++ -std=c++11 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
+// RUN: %clang_cc1 %s -x c++ -std=c++20 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics \
// RUN: -fptrauth-vtable-pointer-type-discrimination \
// RUN: -fptrauth-vtable-pointer-address-discrimination \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=CHECK,BOTH %s
@@ -78,6 +78,27 @@ struct authenticated(default_key, default_address_discrimination, custom_discrim
virtual void g();
};
+// CHECK: @_ZTVN5test19ConstEvalE = external unnamed_addr constant { [3 x ptr] }, align 8
+// 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
+// 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
+// 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
+
+struct authenticated(default_key, address_discrimination, no_extra_discrimination) ConstEval {
+ consteval ConstEval() {}
+ virtual void f();
+};
+
+// clang used to bail out with error message "could not emit constant value abstractly".
+ConstEval ce;
+
+struct ConstEvalDerived : public ConstEval {
+public:
+ consteval ConstEvalDerived() {}
+};
+
+// clang used to emit an undef initializer.
+ConstEvalDerived ced;
+
template <typename T>
struct SubClass : T {
virtual void g();
``````````
</details>
https://github.com/llvm/llvm-project/pull/155036
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