forked from OSchip/llvm-project
[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(). llvm-svn: 238627
This commit is contained in:
Reid Kleckner
parent
42fb96652b
commit
e6531a5588
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@ -74,17 +74,15 @@ private:
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int escapeRegNode(Function &F);
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// Module-level type getters.
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Type *getEHRegistrationType();
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Type *getSEH3RegistrationType();
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Type *getSEH4RegistrationType();
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Type *getCXXEH3RegistrationType();
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Type *getEHLinkRegistrationType();
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Type *getSEHRegistrationType();
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Type *getCXXEHRegistrationType();
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// Per-module data.
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Module *TheModule = nullptr;
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StructType *EHRegistrationTy = nullptr;
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StructType *CXXEH3RegistrationTy = nullptr;
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StructType *SEH3RegistrationTy = nullptr;
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StructType *SEH4RegistrationTy = nullptr;
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StructType *EHLinkRegistrationTy = nullptr;
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StructType *CXXEHRegistrationTy = nullptr;
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StructType *SEHRegistrationTy = nullptr;
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// Per-function state
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EHPersonality Personality = EHPersonality::Unknown;
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@ -117,10 +115,9 @@ bool WinEHStatePass::doInitialization(Module &M) {
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bool WinEHStatePass::doFinalization(Module &M) {
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assert(TheModule == &M);
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TheModule = nullptr;
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EHRegistrationTy = nullptr;
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CXXEH3RegistrationTy = nullptr;
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SEH3RegistrationTy = nullptr;
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SEH4RegistrationTy = nullptr;
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EHLinkRegistrationTy = nullptr;
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CXXEHRegistrationTy = nullptr;
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SEHRegistrationTy = nullptr;
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return false;
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}
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@ -182,17 +179,17 @@ bool WinEHStatePass::runOnFunction(Function &F) {
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/// EHRegistrationNode *Next;
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/// PEXCEPTION_ROUTINE Handler;
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/// };
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Type *WinEHStatePass::getEHRegistrationType() {
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if (EHRegistrationTy)
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return EHRegistrationTy;
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Type *WinEHStatePass::getEHLinkRegistrationType() {
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if (EHLinkRegistrationTy)
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return EHLinkRegistrationTy;
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LLVMContext &Context = TheModule->getContext();
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EHRegistrationTy = StructType::create(Context, "EHRegistrationNode");
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EHLinkRegistrationTy = StructType::create(Context, "EHRegistrationNode");
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Type *FieldTys[] = {
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EHRegistrationTy->getPointerTo(0), // EHRegistrationNode *Next
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EHLinkRegistrationTy->getPointerTo(0), // EHRegistrationNode *Next
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Type::getInt8PtrTy(Context) // EXCEPTION_DISPOSITION (*Handler)(...)
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};
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EHRegistrationTy->setBody(FieldTys, false);
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return EHRegistrationTy;
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EHLinkRegistrationTy->setBody(FieldTys, false);
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return EHLinkRegistrationTy;
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}
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/// The __CxxFrameHandler3 registration node:
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@ -201,40 +198,21 @@ Type *WinEHStatePass::getEHRegistrationType() {
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/// EHRegistrationNode SubRecord;
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/// int32_t TryLevel;
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/// };
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Type *WinEHStatePass::getCXXEH3RegistrationType() {
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if (CXXEH3RegistrationTy)
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return CXXEH3RegistrationTy;
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Type *WinEHStatePass::getCXXEHRegistrationType() {
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if (CXXEHRegistrationTy)
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return CXXEHRegistrationTy;
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LLVMContext &Context = TheModule->getContext();
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Type *FieldTys[] = {
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Type::getInt8PtrTy(Context), // void *SavedESP
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getEHRegistrationType(), // EHRegistrationNode SubRecord
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getEHLinkRegistrationType(), // EHRegistrationNode SubRecord
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Type::getInt32Ty(Context) // int32_t TryLevel
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};
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CXXEH3RegistrationTy =
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CXXEHRegistrationTy =
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StructType::create(FieldTys, "CXXExceptionRegistration");
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return CXXEH3RegistrationTy;
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return CXXEHRegistrationTy;
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}
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/// The _except_handler3 registration node:
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/// struct EH3ExceptionRegistration {
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/// EHRegistrationNode SubRecord;
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/// void *ScopeTable;
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/// int32_t TryLevel;
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/// };
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Type *WinEHStatePass::getSEH3RegistrationType() {
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if (SEH3RegistrationTy)
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return SEH3RegistrationTy;
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LLVMContext &Context = TheModule->getContext();
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Type *FieldTys[] = {
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getEHRegistrationType(), // EHRegistrationNode SubRecord
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Type::getInt8PtrTy(Context), // void *ScopeTable
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Type::getInt32Ty(Context) // int32_t TryLevel
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};
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SEH3RegistrationTy = StructType::create(FieldTys, "EH3ExceptionRegistration");
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return SEH3RegistrationTy;
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}
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/// The _except_handler4 registration node:
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/// The _except_handler3/4 registration node:
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/// struct EH4ExceptionRegistration {
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/// void *SavedESP;
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/// _EXCEPTION_POINTERS *ExceptionPointers;
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@ -242,19 +220,19 @@ Type *WinEHStatePass::getSEH3RegistrationType() {
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/// int32_t EncodedScopeTable;
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/// int32_t TryLevel;
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/// };
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Type *WinEHStatePass::getSEH4RegistrationType() {
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if (SEH4RegistrationTy)
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return SEH4RegistrationTy;
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Type *WinEHStatePass::getSEHRegistrationType() {
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if (SEHRegistrationTy)
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return SEHRegistrationTy;
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LLVMContext &Context = TheModule->getContext();
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Type *FieldTys[] = {
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Type::getInt8PtrTy(Context), // void *SavedESP
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Type::getInt8PtrTy(Context), // void *ExceptionPointers
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getEHRegistrationType(), // EHRegistrationNode SubRecord
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getEHLinkRegistrationType(), // EHRegistrationNode SubRecord
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Type::getInt32Ty(Context), // int32_t EncodedScopeTable
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Type::getInt32Ty(Context) // int32_t TryLevel
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};
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SEH4RegistrationTy = StructType::create(FieldTys, "EH4ExceptionRegistration");
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return SEH4RegistrationTy;
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SEHRegistrationTy = StructType::create(FieldTys, "SEHExceptionRegistration");
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return SEHRegistrationTy;
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}
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// Emit an exception registration record. These are stack allocations with the
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@ -268,8 +246,8 @@ void WinEHStatePass::emitExceptionRegistrationRecord(Function *F) {
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StringRef PersonalityName = PersonalityFn->getName();
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IRBuilder<> Builder(&F->getEntryBlock(), F->getEntryBlock().begin());
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Type *Int8PtrType = Builder.getInt8PtrTy();
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if (PersonalityName == "__CxxFrameHandler3") {
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RegNodeTy = getCXXEH3RegistrationType();
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if (Personality == EHPersonality::MSVC_CXX) {
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RegNodeTy = getCXXEHRegistrationType();
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RegNode = Builder.CreateAlloca(RegNodeTy);
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// FIXME: We can skip this in -GS- mode, when we figure that out.
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// SavedESP = llvm.stacksave()
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@ -283,33 +261,35 @@ void WinEHStatePass::emitExceptionRegistrationRecord(Function *F) {
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Function *Trampoline = generateLSDAInEAXThunk(F);
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Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 1);
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linkExceptionRegistration(Builder, Trampoline);
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} else if (PersonalityName == "_except_handler3") {
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RegNodeTy = getSEH3RegistrationType();
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RegNode = Builder.CreateAlloca(RegNodeTy);
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// TryLevel = -1
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StateFieldIndex = 2;
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insertStateNumberStore(RegNode, Builder.GetInsertPoint(), -1);
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// ScopeTable = llvm.x86.seh.lsda(F)
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Value *LSDA = emitEHLSDA(Builder, F);
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Builder.CreateStore(LSDA, Builder.CreateStructGEP(RegNodeTy, RegNode, 1));
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Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 0);
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linkExceptionRegistration(Builder, PersonalityFn);
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} else if (PersonalityName == "_except_handler4") {
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RegNodeTy = getSEH4RegistrationType();
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} else if (Personality == EHPersonality::MSVC_X86SEH) {
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// If _except_handler4 is in use, some additional guard checks and prologue
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// stuff is required.
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bool UseStackGuard = (PersonalityName == "_except_handler4");
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RegNodeTy = getSEHRegistrationType();
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RegNode = Builder.CreateAlloca(RegNodeTy);
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// SavedESP = llvm.stacksave()
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Value *SP = Builder.CreateCall(
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Intrinsic::getDeclaration(TheModule, Intrinsic::stacksave), {});
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Builder.CreateStore(SP, Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
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// TryLevel = -1
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// TryLevel = -2 / -1
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StateFieldIndex = 4;
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insertStateNumberStore(RegNode, Builder.GetInsertPoint(), -1);
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// FIXME: XOR the LSDA with __security_cookie.
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insertStateNumberStore(RegNode, Builder.GetInsertPoint(),
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UseStackGuard ? -2 : -1);
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// ScopeTable = llvm.x86.seh.lsda(F)
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Value *FI8 = Builder.CreateBitCast(F, Int8PtrType);
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Value *LSDA = Builder.CreateCall(
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Intrinsic::getDeclaration(TheModule, Intrinsic::x86_seh_lsda), FI8);
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Builder.CreateStore(LSDA, Builder.CreateStructGEP(RegNodeTy, RegNode, 1));
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Type *Int32Ty = Type::getInt32Ty(TheModule->getContext());
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LSDA = Builder.CreatePtrToInt(LSDA, Int32Ty);
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// If using _except_handler4, xor the address of the table with
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// __security_cookie.
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if (UseStackGuard) {
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Value *Cookie =
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TheModule->getOrInsertGlobal("__security_cookie", Int32Ty);
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Value *Val = Builder.CreateLoad(Int32Ty, Cookie);
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LSDA = Builder.CreateXor(LSDA, Val);
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}
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Builder.CreateStore(LSDA, Builder.CreateStructGEP(RegNodeTy, RegNode, 3));
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Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 2);
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linkExceptionRegistration(Builder, PersonalityFn);
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} else {
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@ -372,7 +352,7 @@ Function *WinEHStatePass::generateLSDAInEAXThunk(Function *ParentFunc) {
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void WinEHStatePass::linkExceptionRegistration(IRBuilder<> &Builder,
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Value *Handler) {
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Type *LinkTy = getEHRegistrationType();
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Type *LinkTy = getEHLinkRegistrationType();
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// Handler = Handler
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Handler = Builder.CreateBitCast(Handler, Builder.getInt8PtrTy());
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Builder.CreateStore(Handler, Builder.CreateStructGEP(LinkTy, Link, 1));
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@ -392,7 +372,7 @@ void WinEHStatePass::unlinkExceptionRegistration(IRBuilder<> &Builder) {
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Builder.Insert(GEP);
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Link = GEP;
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}
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Type *LinkTy = getEHRegistrationType();
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Type *LinkTy = getEHLinkRegistrationType();
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// [fs:00] = Link->Next
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Value *Next =
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Builder.CreateLoad(Builder.CreateStructGEP(LinkTy, Link, 0));
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@ -24,10 +24,10 @@ catchall:
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; CHECK: subl ${{[0-9]+}}, %esp
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; CHECK: movl $-1, -4(%ebp)
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; CHECK: movl $L__ehtable$use_except_handler3, -8(%ebp)
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; CHECK: leal -16(%ebp), %[[node:[^ ,]*]]
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; CHECK: movl $__except_handler3, -12(%ebp)
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; CHECK: movl %fs:0, %[[next:[^ ,]*]]
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; CHECK: movl %[[next]], -16(%ebp)
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; CHECK: leal -16(%ebp), %[[node:[^ ,]*]]
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; CHECK: movl %[[node]], %fs:0
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; CHECK: calll _may_throw_or_crash
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; CHECK: movl -16(%ebp), %[[next:[^ ,]*]]
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@ -50,8 +50,10 @@ catchall:
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; CHECK: movl %esp, %ebp
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; CHECK: subl ${{[0-9]+}}, %esp
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; CHECK: movl %esp, -24(%ebp)
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; CHECK: movl $-1, -4(%ebp)
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; CHECK: movl $L__ehtable$use_except_handler4, -20(%ebp)
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; CHECK: movl $-2, -4(%ebp)
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; CHECK: movl $L__ehtable$use_except_handler4, %[[lsda:[^ ,]*]]
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; CHECK: xorl ___security_cookie, %[[lsda]]
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; CHECK: movl %[[lsda]], -8(%ebp)
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; CHECK: leal -16(%ebp), %[[node:[^ ,]*]]
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; CHECK: movl $__except_handler4, -12(%ebp)
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; CHECK: movl %fs:0, %[[next:[^ ,]*]]
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