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author | Philip Reames <listmail@philipreames.com> | 2015-01-16 23:16:12 +0000 |
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committer | Philip Reames <listmail@philipreames.com> | 2015-01-16 23:16:12 +0000 |
commit | 36319538d0981498c9eb6ba14066049d653298a5 (patch) | |
tree | cb20cd8a5b66faeafbb545b6cefa2ccd46e641ae /llvm/lib/CodeGen/ShadowStackGC.cpp | |
parent | 6bfd398022a03301f2c86d38143706a0423e7258 (diff) | |
download | bcm5719-llvm-36319538d0981498c9eb6ba14066049d653298a5.tar.gz bcm5719-llvm-36319538d0981498c9eb6ba14066049d653298a5.zip |
clang-format all the GC related files (NFC)
Nothing interesting here...
llvm-svn: 226342
Diffstat (limited to 'llvm/lib/CodeGen/ShadowStackGC.cpp')
-rw-r--r-- | llvm/lib/CodeGen/ShadowStackGC.cpp | 384 |
1 files changed, 190 insertions, 194 deletions
diff --git a/llvm/lib/CodeGen/ShadowStackGC.cpp b/llvm/lib/CodeGen/ShadowStackGC.cpp index 181cb8c435c..163d0efc07a 100644 --- a/llvm/lib/CodeGen/ShadowStackGC.cpp +++ b/llvm/lib/CodeGen/ShadowStackGC.cpp @@ -39,161 +39,156 @@ using namespace llvm; namespace { - class ShadowStackGC : public GCStrategy { - /// RootChain - This is the global linked-list that contains the chain of GC - /// roots. - GlobalVariable *Head; - - /// StackEntryTy - Abstract type of a link in the shadow stack. - /// - StructType *StackEntryTy; - StructType *FrameMapTy; - - /// Roots - GC roots in the current function. Each is a pair of the - /// intrinsic call and its corresponding alloca. - std::vector<std::pair<CallInst*,AllocaInst*> > Roots; - - public: - ShadowStackGC(); - - bool initializeCustomLowering(Module &M) override; - bool performCustomLowering(Function &F) override; - - private: - bool IsNullValue(Value *V); - Constant *GetFrameMap(Function &F); - Type* GetConcreteStackEntryType(Function &F); - void CollectRoots(Function &F); - static GetElementPtrInst *CreateGEP(LLVMContext &Context, - IRBuilder<> &B, Value *BasePtr, - int Idx1, const char *Name); - static GetElementPtrInst *CreateGEP(LLVMContext &Context, - IRBuilder<> &B, Value *BasePtr, - int Idx1, int Idx2, const char *Name); - }; +class ShadowStackGC : public GCStrategy { + /// RootChain - This is the global linked-list that contains the chain of GC + /// roots. + GlobalVariable *Head; + /// StackEntryTy - Abstract type of a link in the shadow stack. + /// + StructType *StackEntryTy; + StructType *FrameMapTy; + + /// Roots - GC roots in the current function. Each is a pair of the + /// intrinsic call and its corresponding alloca. + std::vector<std::pair<CallInst *, AllocaInst *>> Roots; + +public: + ShadowStackGC(); + + bool initializeCustomLowering(Module &M) override; + bool performCustomLowering(Function &F) override; + +private: + bool IsNullValue(Value *V); + Constant *GetFrameMap(Function &F); + Type *GetConcreteStackEntryType(Function &F); + void CollectRoots(Function &F); + static GetElementPtrInst *CreateGEP(LLVMContext &Context, IRBuilder<> &B, + Value *BasePtr, int Idx1, + const char *Name); + static GetElementPtrInst *CreateGEP(LLVMContext &Context, IRBuilder<> &B, + Value *BasePtr, int Idx1, int Idx2, + const char *Name); +}; } static GCRegistry::Add<ShadowStackGC> -X("shadow-stack", "Very portable GC for uncooperative code generators"); + X("shadow-stack", "Very portable GC for uncooperative code generators"); namespace { - /// EscapeEnumerator - This is a little algorithm to find all escape points - /// from a function so that "finally"-style code can be inserted. In addition - /// to finding the existing return and unwind instructions, it also (if - /// necessary) transforms any call instructions into invokes and sends them to - /// a landing pad. - /// - /// It's wrapped up in a state machine using the same transform C# uses for - /// 'yield return' enumerators, This transform allows it to be non-allocating. - class EscapeEnumerator { - Function &F; - const char *CleanupBBName; - - // State. - int State; - Function::iterator StateBB, StateE; - IRBuilder<> Builder; - - public: - EscapeEnumerator(Function &F, const char *N = "cleanup") +/// EscapeEnumerator - This is a little algorithm to find all escape points +/// from a function so that "finally"-style code can be inserted. In addition +/// to finding the existing return and unwind instructions, it also (if +/// necessary) transforms any call instructions into invokes and sends them to +/// a landing pad. +/// +/// It's wrapped up in a state machine using the same transform C# uses for +/// 'yield return' enumerators, This transform allows it to be non-allocating. +class EscapeEnumerator { + Function &F; + const char *CleanupBBName; + + // State. + int State; + Function::iterator StateBB, StateE; + IRBuilder<> Builder; + +public: + EscapeEnumerator(Function &F, const char *N = "cleanup") : F(F), CleanupBBName(N), State(0), Builder(F.getContext()) {} - IRBuilder<> *Next() { - switch (State) { - default: + IRBuilder<> *Next() { + switch (State) { + default: + return nullptr; + + case 0: + StateBB = F.begin(); + StateE = F.end(); + State = 1; + + case 1: + // Find all 'return', 'resume', and 'unwind' instructions. + while (StateBB != StateE) { + BasicBlock *CurBB = StateBB++; + + // Branches and invokes do not escape, only unwind, resume, and return + // do. + TerminatorInst *TI = CurBB->getTerminator(); + if (!isa<ReturnInst>(TI) && !isa<ResumeInst>(TI)) + continue; + + Builder.SetInsertPoint(TI->getParent(), TI); + return &Builder; + } + + State = 2; + + // Find all 'call' instructions. + SmallVector<Instruction *, 16> Calls; + for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) + for (BasicBlock::iterator II = BB->begin(), EE = BB->end(); II != EE; + ++II) + if (CallInst *CI = dyn_cast<CallInst>(II)) + if (!CI->getCalledFunction() || + !CI->getCalledFunction()->getIntrinsicID()) + Calls.push_back(CI); + + if (Calls.empty()) return nullptr; - case 0: - StateBB = F.begin(); - StateE = F.end(); - State = 1; - - case 1: - // Find all 'return', 'resume', and 'unwind' instructions. - while (StateBB != StateE) { - BasicBlock *CurBB = StateBB++; - - // Branches and invokes do not escape, only unwind, resume, and return - // do. - TerminatorInst *TI = CurBB->getTerminator(); - if (!isa<ReturnInst>(TI) && !isa<ResumeInst>(TI)) - continue; - - Builder.SetInsertPoint(TI->getParent(), TI); - return &Builder; - } - - State = 2; - - // Find all 'call' instructions. - SmallVector<Instruction*,16> Calls; - for (Function::iterator BB = F.begin(), - E = F.end(); BB != E; ++BB) - for (BasicBlock::iterator II = BB->begin(), - EE = BB->end(); II != EE; ++II) - if (CallInst *CI = dyn_cast<CallInst>(II)) - if (!CI->getCalledFunction() || - !CI->getCalledFunction()->getIntrinsicID()) - Calls.push_back(CI); - - if (Calls.empty()) - return nullptr; - - // Create a cleanup block. - LLVMContext &C = F.getContext(); - BasicBlock *CleanupBB = BasicBlock::Create(C, CleanupBBName, &F); - Type *ExnTy = StructType::get(Type::getInt8PtrTy(C), - Type::getInt32Ty(C), nullptr); - Constant *PersFn = - F.getParent()-> - getOrInsertFunction("__gcc_personality_v0", - FunctionType::get(Type::getInt32Ty(C), true)); - LandingPadInst *LPad = LandingPadInst::Create(ExnTy, PersFn, 1, - "cleanup.lpad", - CleanupBB); - LPad->setCleanup(true); - ResumeInst *RI = ResumeInst::Create(LPad, CleanupBB); - - // Transform the 'call' instructions into 'invoke's branching to the - // cleanup block. Go in reverse order to make prettier BB names. - SmallVector<Value*,16> Args; - for (unsigned I = Calls.size(); I != 0; ) { - CallInst *CI = cast<CallInst>(Calls[--I]); - - // Split the basic block containing the function call. - BasicBlock *CallBB = CI->getParent(); - BasicBlock *NewBB = + // Create a cleanup block. + LLVMContext &C = F.getContext(); + BasicBlock *CleanupBB = BasicBlock::Create(C, CleanupBBName, &F); + Type *ExnTy = + StructType::get(Type::getInt8PtrTy(C), Type::getInt32Ty(C), nullptr); + Constant *PersFn = F.getParent()->getOrInsertFunction( + "__gcc_personality_v0", FunctionType::get(Type::getInt32Ty(C), true)); + LandingPadInst *LPad = + LandingPadInst::Create(ExnTy, PersFn, 1, "cleanup.lpad", CleanupBB); + LPad->setCleanup(true); + ResumeInst *RI = ResumeInst::Create(LPad, CleanupBB); + + // Transform the 'call' instructions into 'invoke's branching to the + // cleanup block. Go in reverse order to make prettier BB names. + SmallVector<Value *, 16> Args; + for (unsigned I = Calls.size(); I != 0;) { + CallInst *CI = cast<CallInst>(Calls[--I]); + + // Split the basic block containing the function call. + BasicBlock *CallBB = CI->getParent(); + BasicBlock *NewBB = CallBB->splitBasicBlock(CI, CallBB->getName() + ".cont"); - // Remove the unconditional branch inserted at the end of CallBB. - CallBB->getInstList().pop_back(); - NewBB->getInstList().remove(CI); - - // Create a new invoke instruction. - Args.clear(); - CallSite CS(CI); - Args.append(CS.arg_begin(), CS.arg_end()); - - InvokeInst *II = InvokeInst::Create(CI->getCalledValue(), - NewBB, CleanupBB, - Args, CI->getName(), CallBB); - II->setCallingConv(CI->getCallingConv()); - II->setAttributes(CI->getAttributes()); - CI->replaceAllUsesWith(II); - delete CI; - } - - Builder.SetInsertPoint(RI->getParent(), RI); - return &Builder; + // Remove the unconditional branch inserted at the end of CallBB. + CallBB->getInstList().pop_back(); + NewBB->getInstList().remove(CI); + + // Create a new invoke instruction. + Args.clear(); + CallSite CS(CI); + Args.append(CS.arg_begin(), CS.arg_end()); + + InvokeInst *II = + InvokeInst::Create(CI->getCalledValue(), NewBB, CleanupBB, Args, + CI->getName(), CallBB); + II->setCallingConv(CI->getCallingConv()); + II->setAttributes(CI->getAttributes()); + CI->replaceAllUsesWith(II); + delete CI; } + + Builder.SetInsertPoint(RI->getParent(), RI); + return &Builder; } - }; + } +}; } // ----------------------------------------------------------------------------- -void llvm::linkShadowStackGC() { } +void llvm::linkShadowStackGC() {} ShadowStackGC::ShadowStackGC() : Head(nullptr), StackEntryTy(nullptr) { InitRoots = true; @@ -206,7 +201,7 @@ Constant *ShadowStackGC::GetFrameMap(Function &F) { // Truncate the ShadowStackDescriptor if some metadata is null. unsigned NumMeta = 0; - SmallVector<Constant*, 16> Metadata; + SmallVector<Constant *, 16> Metadata; for (unsigned I = 0; I != Roots.size(); ++I) { Constant *C = cast<Constant>(Roots[I].first->getArgOperand(1)); if (!C->isNullValue()) @@ -216,20 +211,19 @@ Constant *ShadowStackGC::GetFrameMap(Function &F) { Metadata.resize(NumMeta); Type *Int32Ty = Type::getInt32Ty(F.getContext()); - + Constant *BaseElts[] = { - ConstantInt::get(Int32Ty, Roots.size(), false), - ConstantInt::get(Int32Ty, NumMeta, false), + ConstantInt::get(Int32Ty, Roots.size(), false), + ConstantInt::get(Int32Ty, NumMeta, false), }; Constant *DescriptorElts[] = { - ConstantStruct::get(FrameMapTy, BaseElts), - ConstantArray::get(ArrayType::get(VoidPtr, NumMeta), Metadata) - }; + ConstantStruct::get(FrameMapTy, BaseElts), + ConstantArray::get(ArrayType::get(VoidPtr, NumMeta), Metadata)}; + + Type *EltTys[] = {DescriptorElts[0]->getType(), DescriptorElts[1]->getType()}; + StructType *STy = StructType::create(EltTys, "gc_map." + utostr(NumMeta)); - Type *EltTys[] = { DescriptorElts[0]->getType(),DescriptorElts[1]->getType()}; - StructType *STy = StructType::create(EltTys, "gc_map."+utostr(NumMeta)); - Constant *FrameMap = ConstantStruct::get(STy, DescriptorElts); // FIXME: Is this actually dangerous as WritingAnLLVMPass.html claims? Seems @@ -246,24 +240,23 @@ Constant *ShadowStackGC::GetFrameMap(Function &F) { // (which uses a FunctionPassManager (which segfaults (not asserts) if // provided a ModulePass))). Constant *GV = new GlobalVariable(*F.getParent(), FrameMap->getType(), true, - GlobalVariable::InternalLinkage, - FrameMap, "__gc_" + F.getName()); + GlobalVariable::InternalLinkage, FrameMap, + "__gc_" + F.getName()); Constant *GEPIndices[2] = { - ConstantInt::get(Type::getInt32Ty(F.getContext()), 0), - ConstantInt::get(Type::getInt32Ty(F.getContext()), 0) - }; + ConstantInt::get(Type::getInt32Ty(F.getContext()), 0), + ConstantInt::get(Type::getInt32Ty(F.getContext()), 0)}; return ConstantExpr::getGetElementPtr(GV, GEPIndices); } -Type* ShadowStackGC::GetConcreteStackEntryType(Function &F) { +Type *ShadowStackGC::GetConcreteStackEntryType(Function &F) { // doInitialization creates the generic version of this type. - std::vector<Type*> EltTys; + std::vector<Type *> EltTys; EltTys.push_back(StackEntryTy); for (size_t I = 0; I != Roots.size(); I++) EltTys.push_back(Roots[I].second->getAllocatedType()); - - return StructType::create(EltTys, "gc_stackentry."+F.getName().str()); + + return StructType::create(EltTys, "gc_stackentry." + F.getName().str()); } /// doInitialization - If this module uses the GC intrinsics, find them now. If @@ -274,10 +267,10 @@ bool ShadowStackGC::initializeCustomLowering(Module &M) { // int32_t NumMeta; // Number of metadata descriptors. May be < NumRoots. // void *Meta[]; // May be absent for roots without metadata. // }; - std::vector<Type*> EltTys; + std::vector<Type *> EltTys; // 32 bits is ok up to a 32GB stack frame. :) EltTys.push_back(Type::getInt32Ty(M.getContext())); - // Specifies length of variable length array. + // Specifies length of variable length array. EltTys.push_back(Type::getInt32Ty(M.getContext())); FrameMapTy = StructType::create(EltTys, "gc_map"); PointerType *FrameMapPtrTy = PointerType::getUnqual(FrameMapTy); @@ -287,9 +280,9 @@ bool ShadowStackGC::initializeCustomLowering(Module &M) { // FrameMap *Map; // Pointer to constant FrameMap. // void *Roots[]; // Stack roots (in-place array, so we pretend). // }; - + StackEntryTy = StructType::create(M.getContext(), "gc_stackentry"); - + EltTys.clear(); EltTys.push_back(PointerType::getUnqual(StackEntryTy)); EltTys.push_back(FrameMapPtrTy); @@ -301,10 +294,9 @@ bool ShadowStackGC::initializeCustomLowering(Module &M) { if (!Head) { // If the root chain does not exist, insert a new one with linkonce // linkage! - Head = new GlobalVariable(M, StackEntryPtrTy, false, - GlobalValue::LinkOnceAnyLinkage, - Constant::getNullValue(StackEntryPtrTy), - "llvm_gc_root_chain"); + Head = new GlobalVariable( + M, StackEntryPtrTy, false, GlobalValue::LinkOnceAnyLinkage, + Constant::getNullValue(StackEntryPtrTy), "llvm_gc_root_chain"); } else if (Head->hasExternalLinkage() && Head->isDeclaration()) { Head->setInitializer(Constant::getNullValue(StackEntryPtrTy)); Head->setLinkage(GlobalValue::LinkOnceAnyLinkage); @@ -326,15 +318,16 @@ void ShadowStackGC::CollectRoots(Function &F) { assert(Roots.empty() && "Not cleaned up?"); - SmallVector<std::pair<CallInst*, AllocaInst*>, 16> MetaRoots; + SmallVector<std::pair<CallInst *, AllocaInst *>, 16> MetaRoots; for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E;) if (IntrinsicInst *CI = dyn_cast<IntrinsicInst>(II++)) if (Function *F = CI->getCalledFunction()) if (F->getIntrinsicID() == Intrinsic::gcroot) { - std::pair<CallInst*, AllocaInst*> Pair = std::make_pair( - CI, cast<AllocaInst>(CI->getArgOperand(0)->stripPointerCasts())); + std::pair<CallInst *, AllocaInst *> Pair = std::make_pair( + CI, + cast<AllocaInst>(CI->getArgOperand(0)->stripPointerCasts())); if (IsNullValue(CI->getArgOperand(1))) Roots.push_back(Pair); else @@ -346,24 +339,25 @@ void ShadowStackGC::CollectRoots(Function &F) { Roots.insert(Roots.begin(), MetaRoots.begin(), MetaRoots.end()); } -GetElementPtrInst * -ShadowStackGC::CreateGEP(LLVMContext &Context, IRBuilder<> &B, Value *BasePtr, - int Idx, int Idx2, const char *Name) { - Value *Indices[] = { ConstantInt::get(Type::getInt32Ty(Context), 0), - ConstantInt::get(Type::getInt32Ty(Context), Idx), - ConstantInt::get(Type::getInt32Ty(Context), Idx2) }; - Value* Val = B.CreateGEP(BasePtr, Indices, Name); +GetElementPtrInst *ShadowStackGC::CreateGEP(LLVMContext &Context, + IRBuilder<> &B, Value *BasePtr, + int Idx, int Idx2, + const char *Name) { + Value *Indices[] = {ConstantInt::get(Type::getInt32Ty(Context), 0), + ConstantInt::get(Type::getInt32Ty(Context), Idx), + ConstantInt::get(Type::getInt32Ty(Context), Idx2)}; + Value *Val = B.CreateGEP(BasePtr, Indices, Name); assert(isa<GetElementPtrInst>(Val) && "Unexpected folded constant"); return dyn_cast<GetElementPtrInst>(Val); } -GetElementPtrInst * -ShadowStackGC::CreateGEP(LLVMContext &Context, IRBuilder<> &B, Value *BasePtr, - int Idx, const char *Name) { - Value *Indices[] = { ConstantInt::get(Type::getInt32Ty(Context), 0), - ConstantInt::get(Type::getInt32Ty(Context), Idx) }; +GetElementPtrInst *ShadowStackGC::CreateGEP(LLVMContext &Context, + IRBuilder<> &B, Value *BasePtr, + int Idx, const char *Name) { + Value *Indices[] = {ConstantInt::get(Type::getInt32Ty(Context), 0), + ConstantInt::get(Type::getInt32Ty(Context), Idx)}; Value *Val = B.CreateGEP(BasePtr, Indices, Name); assert(isa<GetElementPtrInst>(Val) && "Unexpected folded constant"); @@ -374,7 +368,7 @@ ShadowStackGC::CreateGEP(LLVMContext &Context, IRBuilder<> &B, Value *BasePtr, /// runOnFunction - Insert code to maintain the shadow stack. bool ShadowStackGC::performCustomLowering(Function &F) { LLVMContext &Context = F.getContext(); - + // Find calls to llvm.gcroot. CollectRoots(F); @@ -391,16 +385,17 @@ bool ShadowStackGC::performCustomLowering(Function &F) { BasicBlock::iterator IP = F.getEntryBlock().begin(); IRBuilder<> AtEntry(IP->getParent(), IP); - Instruction *StackEntry = AtEntry.CreateAlloca(ConcreteStackEntryTy, nullptr, - "gc_frame"); + Instruction *StackEntry = + AtEntry.CreateAlloca(ConcreteStackEntryTy, nullptr, "gc_frame"); - while (isa<AllocaInst>(IP)) ++IP; + while (isa<AllocaInst>(IP)) + ++IP; AtEntry.SetInsertPoint(IP->getParent(), IP); // Initialize the map pointer and load the current head of the shadow stack. - Instruction *CurrentHead = AtEntry.CreateLoad(Head, "gc_currhead"); - Instruction *EntryMapPtr = CreateGEP(Context, AtEntry, StackEntry, - 0,1,"gc_frame.map"); + Instruction *CurrentHead = AtEntry.CreateLoad(Head, "gc_currhead"); + Instruction *EntryMapPtr = + CreateGEP(Context, AtEntry, StackEntry, 0, 1, "gc_frame.map"); AtEntry.CreateStore(FrameMap, EntryMapPtr); // After all the allocas... @@ -418,14 +413,15 @@ bool ShadowStackGC::performCustomLowering(Function &F) { // really necessary (the collector would never see the intermediate state at // runtime), but it's nicer not to push the half-initialized entry onto the // shadow stack. - while (isa<StoreInst>(IP)) ++IP; + while (isa<StoreInst>(IP)) + ++IP; AtEntry.SetInsertPoint(IP->getParent(), IP); // Push the entry onto the shadow stack. - Instruction *EntryNextPtr = CreateGEP(Context, AtEntry, - StackEntry,0,0,"gc_frame.next"); - Instruction *NewHeadVal = CreateGEP(Context, AtEntry, - StackEntry, 0, "gc_newhead"); + Instruction *EntryNextPtr = + CreateGEP(Context, AtEntry, StackEntry, 0, 0, "gc_frame.next"); + Instruction *NewHeadVal = + CreateGEP(Context, AtEntry, StackEntry, 0, "gc_newhead"); AtEntry.CreateStore(CurrentHead, EntryNextPtr); AtEntry.CreateStore(NewHeadVal, Head); @@ -434,10 +430,10 @@ bool ShadowStackGC::performCustomLowering(Function &F) { while (IRBuilder<> *AtExit = EE.Next()) { // Pop the entry from the shadow stack. Don't reuse CurrentHead from // AtEntry, since that would make the value live for the entire function. - Instruction *EntryNextPtr2 = CreateGEP(Context, *AtExit, StackEntry, 0, 0, - "gc_frame.next"); + Instruction *EntryNextPtr2 = + CreateGEP(Context, *AtExit, StackEntry, 0, 0, "gc_frame.next"); Value *SavedHead = AtExit->CreateLoad(EntryNextPtr2, "gc_savedhead"); - AtExit->CreateStore(SavedHead, Head); + AtExit->CreateStore(SavedHead, Head); } // Delete the original allocas (which are no longer used) and the intrinsic |