From bfa311df8ca99f0565af96b7882dc25ce12da188 Mon Sep 17 00:00:00 2001 From: Reid Kleckner Date: Fri, 29 May 2015 22:57:46 +0000 Subject: [PATCH] [WinEH] Adjust the 32-bit SEH prologue to better match reality It turns out that _except_handler3 and _except_handler4 really use the same stack allocation layout, at least today. They just make different choices about encoding the LSDA. This is in preparation for lowering the llvm.eh.exceptioninfo(). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238627 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/X86WinEHState.cpp | 124 +++++++++++++------------------ test/CodeGen/X86/win32-eh.ll | 8 +- 2 files changed, 57 insertions(+), 75 deletions(-) diff --git a/lib/Target/X86/X86WinEHState.cpp b/lib/Target/X86/X86WinEHState.cpp index 8a4a8161a03..0dbdab89682 100644 --- a/lib/Target/X86/X86WinEHState.cpp +++ b/lib/Target/X86/X86WinEHState.cpp @@ -74,17 +74,15 @@ private: int escapeRegNode(Function &F); // Module-level type getters. - Type *getEHRegistrationType(); - Type *getSEH3RegistrationType(); - Type *getSEH4RegistrationType(); - Type *getCXXEH3RegistrationType(); + Type *getEHLinkRegistrationType(); + Type *getSEHRegistrationType(); + Type *getCXXEHRegistrationType(); // Per-module data. Module *TheModule = nullptr; - StructType *EHRegistrationTy = nullptr; - StructType *CXXEH3RegistrationTy = nullptr; - StructType *SEH3RegistrationTy = nullptr; - StructType *SEH4RegistrationTy = nullptr; + StructType *EHLinkRegistrationTy = nullptr; + StructType *CXXEHRegistrationTy = nullptr; + StructType *SEHRegistrationTy = nullptr; // Per-function state EHPersonality Personality = EHPersonality::Unknown; @@ -117,10 +115,9 @@ bool WinEHStatePass::doInitialization(Module &M) { bool WinEHStatePass::doFinalization(Module &M) { assert(TheModule == &M); TheModule = nullptr; - EHRegistrationTy = nullptr; - CXXEH3RegistrationTy = nullptr; - SEH3RegistrationTy = nullptr; - SEH4RegistrationTy = nullptr; + EHLinkRegistrationTy = nullptr; + CXXEHRegistrationTy = nullptr; + SEHRegistrationTy = nullptr; return false; } @@ -182,17 +179,17 @@ bool WinEHStatePass::runOnFunction(Function &F) { /// EHRegistrationNode *Next; /// PEXCEPTION_ROUTINE Handler; /// }; -Type *WinEHStatePass::getEHRegistrationType() { - if (EHRegistrationTy) - return EHRegistrationTy; +Type *WinEHStatePass::getEHLinkRegistrationType() { + if (EHLinkRegistrationTy) + return EHLinkRegistrationTy; LLVMContext &Context = TheModule->getContext(); - EHRegistrationTy = StructType::create(Context, "EHRegistrationNode"); + EHLinkRegistrationTy = StructType::create(Context, "EHRegistrationNode"); Type *FieldTys[] = { - EHRegistrationTy->getPointerTo(0), // EHRegistrationNode *Next + EHLinkRegistrationTy->getPointerTo(0), // EHRegistrationNode *Next Type::getInt8PtrTy(Context) // EXCEPTION_DISPOSITION (*Handler)(...) }; - EHRegistrationTy->setBody(FieldTys, false); - return EHRegistrationTy; + EHLinkRegistrationTy->setBody(FieldTys, false); + return EHLinkRegistrationTy; } /// The __CxxFrameHandler3 registration node: @@ -201,40 +198,21 @@ Type *WinEHStatePass::getEHRegistrationType() { /// EHRegistrationNode SubRecord; /// int32_t TryLevel; /// }; -Type *WinEHStatePass::getCXXEH3RegistrationType() { - if (CXXEH3RegistrationTy) - return CXXEH3RegistrationTy; +Type *WinEHStatePass::getCXXEHRegistrationType() { + if (CXXEHRegistrationTy) + return CXXEHRegistrationTy; LLVMContext &Context = TheModule->getContext(); Type *FieldTys[] = { Type::getInt8PtrTy(Context), // void *SavedESP - getEHRegistrationType(), // EHRegistrationNode SubRecord + getEHLinkRegistrationType(), // EHRegistrationNode SubRecord Type::getInt32Ty(Context) // int32_t TryLevel }; - CXXEH3RegistrationTy = + CXXEHRegistrationTy = StructType::create(FieldTys, "CXXExceptionRegistration"); - return CXXEH3RegistrationTy; + return CXXEHRegistrationTy; } -/// The _except_handler3 registration node: -/// struct EH3ExceptionRegistration { -/// EHRegistrationNode SubRecord; -/// void *ScopeTable; -/// int32_t TryLevel; -/// }; -Type *WinEHStatePass::getSEH3RegistrationType() { - if (SEH3RegistrationTy) - return SEH3RegistrationTy; - LLVMContext &Context = TheModule->getContext(); - Type *FieldTys[] = { - getEHRegistrationType(), // EHRegistrationNode SubRecord - Type::getInt8PtrTy(Context), // void *ScopeTable - Type::getInt32Ty(Context) // int32_t TryLevel - }; - SEH3RegistrationTy = StructType::create(FieldTys, "EH3ExceptionRegistration"); - return SEH3RegistrationTy; -} - -/// The _except_handler4 registration node: +/// The _except_handler3/4 registration node: /// struct EH4ExceptionRegistration { /// void *SavedESP; /// _EXCEPTION_POINTERS *ExceptionPointers; @@ -242,19 +220,19 @@ Type *WinEHStatePass::getSEH3RegistrationType() { /// int32_t EncodedScopeTable; /// int32_t TryLevel; /// }; -Type *WinEHStatePass::getSEH4RegistrationType() { - if (SEH4RegistrationTy) - return SEH4RegistrationTy; +Type *WinEHStatePass::getSEHRegistrationType() { + if (SEHRegistrationTy) + return SEHRegistrationTy; LLVMContext &Context = TheModule->getContext(); Type *FieldTys[] = { Type::getInt8PtrTy(Context), // void *SavedESP Type::getInt8PtrTy(Context), // void *ExceptionPointers - getEHRegistrationType(), // EHRegistrationNode SubRecord + getEHLinkRegistrationType(), // EHRegistrationNode SubRecord Type::getInt32Ty(Context), // int32_t EncodedScopeTable Type::getInt32Ty(Context) // int32_t TryLevel }; - SEH4RegistrationTy = StructType::create(FieldTys, "EH4ExceptionRegistration"); - return SEH4RegistrationTy; + SEHRegistrationTy = StructType::create(FieldTys, "SEHExceptionRegistration"); + return SEHRegistrationTy; } // Emit an exception registration record. These are stack allocations with the @@ -268,8 +246,8 @@ void WinEHStatePass::emitExceptionRegistrationRecord(Function *F) { StringRef PersonalityName = PersonalityFn->getName(); IRBuilder<> Builder(&F->getEntryBlock(), F->getEntryBlock().begin()); Type *Int8PtrType = Builder.getInt8PtrTy(); - if (PersonalityName == "__CxxFrameHandler3") { - RegNodeTy = getCXXEH3RegistrationType(); + if (Personality == EHPersonality::MSVC_CXX) { + RegNodeTy = getCXXEHRegistrationType(); RegNode = Builder.CreateAlloca(RegNodeTy); // FIXME: We can skip this in -GS- mode, when we figure that out. // SavedESP = llvm.stacksave() @@ -283,33 +261,35 @@ void WinEHStatePass::emitExceptionRegistrationRecord(Function *F) { Function *Trampoline = generateLSDAInEAXThunk(F); Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 1); linkExceptionRegistration(Builder, Trampoline); - } else if (PersonalityName == "_except_handler3") { - RegNodeTy = getSEH3RegistrationType(); - RegNode = Builder.CreateAlloca(RegNodeTy); - // TryLevel = -1 - StateFieldIndex = 2; - insertStateNumberStore(RegNode, Builder.GetInsertPoint(), -1); - // ScopeTable = llvm.x86.seh.lsda(F) - Value *LSDA = emitEHLSDA(Builder, F); - Builder.CreateStore(LSDA, Builder.CreateStructGEP(RegNodeTy, RegNode, 1)); - Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 0); - linkExceptionRegistration(Builder, PersonalityFn); - } else if (PersonalityName == "_except_handler4") { - RegNodeTy = getSEH4RegistrationType(); + } else if (Personality == EHPersonality::MSVC_X86SEH) { + // If _except_handler4 is in use, some additional guard checks and prologue + // stuff is required. + bool UseStackGuard = (PersonalityName == "_except_handler4"); + RegNodeTy = getSEHRegistrationType(); RegNode = Builder.CreateAlloca(RegNodeTy); // SavedESP = llvm.stacksave() Value *SP = Builder.CreateCall( Intrinsic::getDeclaration(TheModule, Intrinsic::stacksave), {}); Builder.CreateStore(SP, Builder.CreateStructGEP(RegNodeTy, RegNode, 0)); - // TryLevel = -1 + // TryLevel = -2 / -1 StateFieldIndex = 4; - insertStateNumberStore(RegNode, Builder.GetInsertPoint(), -1); - // FIXME: XOR the LSDA with __security_cookie. + insertStateNumberStore(RegNode, Builder.GetInsertPoint(), + UseStackGuard ? -2 : -1); // ScopeTable = llvm.x86.seh.lsda(F) Value *FI8 = Builder.CreateBitCast(F, Int8PtrType); Value *LSDA = Builder.CreateCall( Intrinsic::getDeclaration(TheModule, Intrinsic::x86_seh_lsda), FI8); - Builder.CreateStore(LSDA, Builder.CreateStructGEP(RegNodeTy, RegNode, 1)); + Type *Int32Ty = Type::getInt32Ty(TheModule->getContext()); + LSDA = Builder.CreatePtrToInt(LSDA, Int32Ty); + // If using _except_handler4, xor the address of the table with + // __security_cookie. + if (UseStackGuard) { + Value *Cookie = + TheModule->getOrInsertGlobal("__security_cookie", Int32Ty); + Value *Val = Builder.CreateLoad(Int32Ty, Cookie); + LSDA = Builder.CreateXor(LSDA, Val); + } + Builder.CreateStore(LSDA, Builder.CreateStructGEP(RegNodeTy, RegNode, 3)); Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 2); linkExceptionRegistration(Builder, PersonalityFn); } else { @@ -372,7 +352,7 @@ Function *WinEHStatePass::generateLSDAInEAXThunk(Function *ParentFunc) { void WinEHStatePass::linkExceptionRegistration(IRBuilder<> &Builder, Value *Handler) { - Type *LinkTy = getEHRegistrationType(); + Type *LinkTy = getEHLinkRegistrationType(); // Handler = Handler Handler = Builder.CreateBitCast(Handler, Builder.getInt8PtrTy()); Builder.CreateStore(Handler, Builder.CreateStructGEP(LinkTy, Link, 1)); @@ -392,7 +372,7 @@ void WinEHStatePass::unlinkExceptionRegistration(IRBuilder<> &Builder) { Builder.Insert(GEP); Link = GEP; } - Type *LinkTy = getEHRegistrationType(); + Type *LinkTy = getEHLinkRegistrationType(); // [fs:00] = Link->Next Value *Next = Builder.CreateLoad(Builder.CreateStructGEP(LinkTy, Link, 0)); diff --git a/test/CodeGen/X86/win32-eh.ll b/test/CodeGen/X86/win32-eh.ll index ea1029ea3f2..42c9d9e2240 100644 --- a/test/CodeGen/X86/win32-eh.ll +++ b/test/CodeGen/X86/win32-eh.ll @@ -24,10 +24,10 @@ catchall: ; CHECK: subl ${{[0-9]+}}, %esp ; CHECK: movl $-1, -4(%ebp) ; CHECK: movl $L__ehtable$use_except_handler3, -8(%ebp) +; CHECK: leal -16(%ebp), %[[node:[^ ,]*]] ; CHECK: movl $__except_handler3, -12(%ebp) ; CHECK: movl %fs:0, %[[next:[^ ,]*]] ; CHECK: movl %[[next]], -16(%ebp) -; CHECK: leal -16(%ebp), %[[node:[^ ,]*]] ; CHECK: movl %[[node]], %fs:0 ; CHECK: calll _may_throw_or_crash ; CHECK: movl -16(%ebp), %[[next:[^ ,]*]] @@ -50,8 +50,10 @@ catchall: ; CHECK: movl %esp, %ebp ; CHECK: subl ${{[0-9]+}}, %esp ; CHECK: movl %esp, -24(%ebp) -; CHECK: movl $-1, -4(%ebp) -; CHECK: movl $L__ehtable$use_except_handler4, -20(%ebp) +; CHECK: movl $-2, -4(%ebp) +; CHECK: movl $L__ehtable$use_except_handler4, %[[lsda:[^ ,]*]] +; CHECK: xorl ___security_cookie, %[[lsda]] +; CHECK: movl %[[lsda]], -8(%ebp) ; CHECK: leal -16(%ebp), %[[node:[^ ,]*]] ; CHECK: movl $__except_handler4, -12(%ebp) ; CHECK: movl %fs:0, %[[next:[^ ,]*]] -- 2.34.1