diff options
Diffstat (limited to 'clang')
| -rw-r--r-- | clang/lib/CodeGen/ItaniumCXXABI.cpp | 14 | ||||
| -rw-r--r-- | clang/test/CodeGenCXX/arm64.cpp | 36 |
2 files changed, 48 insertions, 2 deletions
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp index bd9e882dac4..08c86176abc 100644 --- a/clang/lib/CodeGen/ItaniumCXXABI.cpp +++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp @@ -45,6 +45,7 @@ class ItaniumCXXABI : public CodeGen::CGCXXABI { protected: bool UseARMMethodPtrABI; bool UseARMGuardVarABI; + bool Use32BitVTableOffsetABI; ItaniumMangleContext &getMangleContext() { return cast<ItaniumMangleContext>(CodeGen::CGCXXABI::getMangleContext()); @@ -55,7 +56,8 @@ public: bool UseARMMethodPtrABI = false, bool UseARMGuardVarABI = false) : CGCXXABI(CGM), UseARMMethodPtrABI(UseARMMethodPtrABI), - UseARMGuardVarABI(UseARMGuardVarABI) { } + UseARMGuardVarABI(UseARMGuardVarABI), + Use32BitVTableOffsetABI(false) { } bool classifyReturnType(CGFunctionInfo &FI) const override; @@ -425,7 +427,9 @@ public: class iOS64CXXABI : public ARMCXXABI { public: - iOS64CXXABI(CodeGen::CodeGenModule &CGM) : ARMCXXABI(CGM) {} + iOS64CXXABI(CodeGen::CodeGenModule &CGM) : ARMCXXABI(CGM) { + Use32BitVTableOffsetABI = true; + } // ARM64 libraries are prepared for non-unique RTTI. bool shouldRTTIBeUnique() const override { return false; } @@ -579,9 +583,15 @@ llvm::Value *ItaniumCXXABI::EmitLoadOfMemberFunctionPointer( CGF.GetVTablePtr(Address(This, VTablePtrAlign), VTableTy, RD); // Apply the offset. + // On ARM64, to reserve extra space in virtual member function pointers, + // we only pay attention to the low 32 bits of the offset. llvm::Value *VTableOffset = FnAsInt; if (!UseARMMethodPtrABI) VTableOffset = Builder.CreateSub(VTableOffset, ptrdiff_1); + if (Use32BitVTableOffsetABI) { + VTableOffset = Builder.CreateTrunc(VTableOffset, CGF.Int32Ty); + VTableOffset = Builder.CreateZExt(VTableOffset, CGM.PtrDiffTy); + } VTable = Builder.CreateGEP(VTable, VTableOffset); // Load the virtual function to call. diff --git a/clang/test/CodeGenCXX/arm64.cpp b/clang/test/CodeGenCXX/arm64.cpp index 19f72726e69..80438397c3f 100644 --- a/clang/test/CodeGenCXX/arm64.cpp +++ b/clang/test/CodeGenCXX/arm64.cpp @@ -84,3 +84,39 @@ namespace test2 { // CHECK-GLOBALS-DAG: @_ZTIN5test21EIiEE = weak_odr constant { {{.*}}, i8* inttoptr (i64 add (i64 ptrtoint ([14 x i8]* @_ZTSN5test21EIiEE to i64), i64 -9223372036854775808) to i8*) } } + +// ARM64 reserves the top half of the vtable offset in virtual +// member pointers. +namespace test3 { + struct A { + virtual void foo(); + virtual void bar(); + }; + + // The offset half of the pointer is still initialized to zero. + // CHECK-GLOBALS-DAG: @_ZN5test34mptrE = global { i64, i64 } { i64 0, i64 1 } + void (A::*mptr)() = &A::foo; + + // CHECK-LABEL: define void @_ZN5test34testEv() + // CHECK: [[TEMP:%.*]] = alloca [[A:.*]], align 8 + // CHECK: [[MEMPTR:%.*]] = load { i64, i64 }, { i64, i64 }* @_ZN5test34mptrE, align 8 + // CHECK: [[ADJUST_AND_IS_VIRTUAL:%.*]] = extractvalue { i64, i64 } [[MEMPTR]], 1 + // CHECK: [[ADJUST:%.*]] = ashr i64 [[ADJUST_AND_IS_VIRTUAL]], 1 + // CHECK: [[T0:%.*]] = bitcast [[A]]* [[TEMP]] to i8* + // CHECK: [[T1:%.*]] = getelementptr inbounds i8, i8* [[T0]], i64 [[ADJUST]] + // CHECK: [[ADJUSTED:%.*]] = bitcast i8* [[T1]] to [[A]]* + // CHECK: [[MEMBER:%.*]] = extractvalue { i64, i64 } [[MEMPTR]], 0 + // CHECK: [[T0:%.*]] = and i64 [[ADJUST_AND_IS_VIRTUAL]], 1 + // CHECK: [[IS_VIRTUAL:%.*]] = icmp ne i64 [[T0]], 0 + // CHECK: br i1 [[IS_VIRTUAL]], + // CHECK: [[T0:%.*]] = bitcast [[A]]* [[ADJUSTED]] to i8** + // CHECK: [[VPTR:%.*]] = load i8*, i8** [[T0]], align 8 + // CHECK: [[TRUNC:%.*]] = trunc i64 [[MEMBER]] to i32 + // CHECK: [[ZEXT:%.*]] = zext i32 [[TRUNC]] to i64 + // CHECK: [[T0:%.*]] = getelementptr i8, i8* [[VPTR]], i64 [[ZEXT]] + // CHECK: [[T1:%.*]] = bitcast i8* [[T0]] to void ([[A]]*)** + // CHECK: load void ([[A]]*)*, void ([[A]]*)** [[T1]], + void test() { + (A().*mptr)(); + } +} |
