diff options
| -rw-r--r-- | lib/CodeGen/CGExpr.cpp | 18 | ||||
| -rw-r--r-- | lib/CodeGen/CodeGenFunction.h | 3 | ||||
| -rw-r--r-- | lib/CodeGen/CodeGenModule.cpp | 4 | ||||
| -rw-r--r-- | test/CodeGen/cfi-check-fail.c | 5 |
4 files changed, 29 insertions, 1 deletions
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp index 38eb345d91..c412456bf7 100644 --- a/lib/CodeGen/CGExpr.cpp +++ b/lib/CodeGen/CGExpr.cpp @@ -2783,6 +2783,24 @@ void CodeGenFunction::EmitCfiSlowPathCheck( EmitBlock(Cont); } +// Emit a stub for __cfi_check function so that the linker knows about this +// symbol in LTO mode. +void CodeGenFunction::EmitCfiCheckStub() { + llvm::Module *M = &CGM.getModule(); + auto &Ctx = M->getContext(); + llvm::Function *F = llvm::Function::Create( + llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy, Int8PtrTy}, false), + llvm::GlobalValue::WeakAnyLinkage, "__cfi_check", M); + llvm::BasicBlock *BB = llvm::BasicBlock::Create(Ctx, "entry", F); + // FIXME: consider emitting an intrinsic call like + // call void @llvm.cfi_check(i64 %0, i8* %1, i8* %2) + // which can be lowered in CrossDSOCFI pass to the actual contents of + // __cfi_check. This would allow inlining of __cfi_check calls. + llvm::CallInst::Create( + llvm::Intrinsic::getDeclaration(M, llvm::Intrinsic::trap), "", BB); + llvm::ReturnInst::Create(Ctx, nullptr, BB); +} + // This function is basically a switch over the CFI failure kind, which is // extracted from CFICheckFailData (1st function argument). Each case is either // llvm.trap or a call to one of the two runtime handlers, based on diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h index ee85e30173..3321bc86c0 100644 --- a/lib/CodeGen/CodeGenFunction.h +++ b/lib/CodeGen/CodeGenFunction.h @@ -3524,6 +3524,9 @@ public: /// "trap-func-name" if specified. llvm::CallInst *EmitTrapCall(llvm::Intrinsic::ID IntrID); + /// \brief Emit a stub for the cross-DSO CFI check function. + void EmitCfiCheckStub(); + /// \brief Emit a cross-DSO CFI failure handling function. void EmitCfiCheckFail(); diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp index 479a390648..6bc7d4f10e 100644 --- a/lib/CodeGen/CodeGenModule.cpp +++ b/lib/CodeGen/CodeGenModule.cpp @@ -406,8 +406,10 @@ void CodeGenModule::Release() { EmitDeferredUnusedCoverageMappings(); if (CoverageMapping) CoverageMapping->emit(); - if (CodeGenOpts.SanitizeCfiCrossDso) + if (CodeGenOpts.SanitizeCfiCrossDso) { CodeGenFunction(*this).EmitCfiCheckFail(); + CodeGenFunction(*this).EmitCfiCheckStub(); + } emitAtAvailableLinkGuard(); emitLLVMUsed(); if (SanStats) diff --git a/test/CodeGen/cfi-check-fail.c b/test/CodeGen/cfi-check-fail.c index b850193b54..0eb786ab96 100644 --- a/test/CodeGen/cfi-check-fail.c +++ b/test/CodeGen/cfi-check-fail.c @@ -72,3 +72,8 @@ void caller(void (*f)()) { // CHECK: [[CONT5]]: // CHECK: ret void + +// CHECK: define weak void @__cfi_check(i64, i8*, i8*) +// CHECK-NOT: } +// CHECK: call void @llvm.trap() +// CHECK-NEXT: ret void |