#include "llvm/CodeGen/GCStrategy.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Module.h"
-#include "llvm/Support/Compiler.h"
+#include "llvm/Support/CallSite.h"
#include "llvm/Support/IRBuilder.h"
using namespace llvm;
namespace {
- class VISIBILITY_HIDDEN ShadowStackGC : public GCStrategy {
+ 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.
///
- const StructType *StackEntryTy;
+ StructType *StackEntryTy;
+ StructType *FrameMapTy;
/// Roots - GC roots in the current function. Each is a pair of the
/// intrinsic call and its corresponding alloca.
private:
bool IsNullValue(Value *V);
Constant *GetFrameMap(Function &F);
- const Type* GetConcreteStackEntryType(Function &F);
+ Type* GetConcreteStackEntryType(Function &F);
void CollectRoots(Function &F);
- static GetElementPtrInst *CreateGEP(IRBuilder<> &B, Value *BasePtr,
+ static GetElementPtrInst *CreateGEP(LLVMContext &Context,
+ IRBuilder<> &B, Value *BasePtr,
int Idx1, const char *Name);
- static GetElementPtrInst *CreateGEP(IRBuilder<> &B, Value *BasePtr,
+ static GetElementPtrInst *CreateGEP(LLVMContext &Context,
+ IRBuilder<> &B, Value *BasePtr,
int Idx1, int Idx2, const char *Name);
};
///
/// 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 VISIBILITY_HIDDEN EscapeEnumerator {
+ class EscapeEnumerator {
Function &F;
const char *CleanupBBName;
public:
EscapeEnumerator(Function &F, const char *N = "cleanup")
- : F(F), CleanupBBName(N), State(0) {}
+ : F(F), CleanupBBName(N), State(0), Builder(F.getContext()) {}
IRBuilder<> *Next() {
switch (State) {
State = 1;
case 1:
- // Find all 'return' and 'unwind' instructions.
+ // Find all 'return', 'resume', and 'unwind' instructions.
while (StateBB != StateE) {
BasicBlock *CurBB = StateBB++;
- // Branches and invokes do not escape, only unwind and return do.
+ // Branches and invokes do not escape, only unwind, resume, and return
+ // do.
TerminatorInst *TI = CurBB->getTerminator();
- if (!isa<UnwindInst>(TI) && !isa<ReturnInst>(TI))
+ if (!isa<ReturnInst>(TI) && !isa<ResumeInst>(TI))
continue;
Builder.SetInsertPoint(TI->getParent(), TI);
return 0;
// Create a cleanup block.
- BasicBlock *CleanupBB = BasicBlock::Create(CleanupBBName, &F);
- UnwindInst *UI = new UnwindInst(CleanupBB);
+ LLVMContext &C = F.getContext();
+ BasicBlock *CleanupBB = BasicBlock::Create(C, CleanupBBName, &F);
+ Type *ExnTy = StructType::get(Type::getInt8PtrTy(C),
+ Type::getInt32Ty(C), NULL);
+ 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.
// Create a new invoke instruction.
Args.clear();
- Args.append(CI->op_begin() + 1, CI->op_end());
+ CallSite CS(CI);
+ Args.append(CS.arg_begin(), CS.arg_end());
- InvokeInst *II = InvokeInst::Create(CI->getOperand(0),
+ InvokeInst *II = InvokeInst::Create(CI->getCalledValue(),
NewBB, CleanupBB,
- Args.begin(), Args.end(),
- CI->getName(), CallBB);
+ Args, CI->getName(), CallBB);
II->setCallingConv(CI->getCallingConv());
II->setAttributes(CI->getAttributes());
CI->replaceAllUsesWith(II);
delete CI;
}
- Builder.SetInsertPoint(UI->getParent(), UI);
+ Builder.SetInsertPoint(RI->getParent(), RI);
return &Builder;
}
}
Constant *ShadowStackGC::GetFrameMap(Function &F) {
// doInitialization creates the abstract type of this value.
-
- Type *VoidPtr = PointerType::getUnqual(Type::Int8Ty);
+ Type *VoidPtr = Type::getInt8PtrTy(F.getContext());
// 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->getOperand(2));
+ Constant *C = cast<Constant>(Roots[I].first->getArgOperand(1));
if (!C->isNullValue())
NumMeta = I + 1;
Metadata.push_back(ConstantExpr::getBitCast(C, VoidPtr));
}
+ Metadata.resize(NumMeta);
+ Type *Int32Ty = Type::getInt32Ty(F.getContext());
+
Constant *BaseElts[] = {
- ConstantInt::get(Type::Int32Ty, Roots.size(), false),
- ConstantInt::get(Type::Int32Ty, NumMeta, false),
+ ConstantInt::get(Int32Ty, Roots.size(), false),
+ ConstantInt::get(Int32Ty, NumMeta, false),
};
Constant *DescriptorElts[] = {
- ConstantStruct::get(BaseElts, 2),
- ConstantArray::get(ArrayType::get(VoidPtr, NumMeta),
- Metadata.begin(), NumMeta)
+ ConstantStruct::get(FrameMapTy, BaseElts),
+ ConstantArray::get(ArrayType::get(VoidPtr, NumMeta), Metadata)
};
- Constant *FrameMap = ConstantStruct::get(DescriptorElts, 2);
-
- std::string TypeName("gc_map.");
- TypeName += utostr(NumMeta);
- F.getParent()->addTypeName(TypeName, FrameMap->getType());
+ 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
// that, short of multithreaded LLVM, it should be safe; all that is
// to be a ModulePass (which means it cannot be in the 'llc' pipeline
// (which uses a FunctionPassManager (which segfaults (not asserts) if
// provided a ModulePass))).
- Constant *GV = new GlobalVariable(FrameMap->getType(), true,
+ Constant *GV = new GlobalVariable(*F.getParent(), FrameMap->getType(), true,
GlobalVariable::InternalLinkage,
- FrameMap, "__gc_" + F.getName(),
- F.getParent());
+ FrameMap, "__gc_" + F.getName());
- Constant *GEPIndices[2] = { ConstantInt::get(Type::Int32Ty, 0),
- ConstantInt::get(Type::Int32Ty, 0) };
- return ConstantExpr::getGetElementPtr(GV, GEPIndices, 2);
+ Constant *GEPIndices[2] = {
+ ConstantInt::get(Type::getInt32Ty(F.getContext()), 0),
+ ConstantInt::get(Type::getInt32Ty(F.getContext()), 0)
+ };
+ return ConstantExpr::getGetElementPtr(GV, GEPIndices);
}
-const Type* ShadowStackGC::GetConcreteStackEntryType(Function &F) {
+Type* ShadowStackGC::GetConcreteStackEntryType(Function &F) {
// doInitialization creates the generic version of this type.
- std::vector<const 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());
- Type *Ty = StructType::get(EltTys);
-
- std::string TypeName("gc_stackentry.");
- TypeName += F.getName();
- F.getParent()->addTypeName(TypeName, Ty);
-
- return Ty;
+
+ return StructType::create(EltTys, "gc_stackentry."+F.getName().str());
}
/// doInitialization - If this module uses the GC intrinsics, find them now. If
// int32_t NumMeta; // Number of metadata descriptors. May be < NumRoots.
// void *Meta[]; // May be absent for roots without metadata.
// };
- std::vector<const Type*> EltTys;
- EltTys.push_back(Type::Int32Ty); // 32 bits is ok up to a 32GB stack frame. :)
- EltTys.push_back(Type::Int32Ty); // Specifies length of variable length array.
- StructType *FrameMapTy = StructType::get(EltTys);
- M.addTypeName("gc_map", FrameMapTy);
+ 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.
+ EltTys.push_back(Type::getInt32Ty(M.getContext()));
+ FrameMapTy = StructType::create(EltTys, "gc_map");
PointerType *FrameMapPtrTy = PointerType::getUnqual(FrameMapTy);
// struct StackEntry {
// FrameMap *Map; // Pointer to constant FrameMap.
// void *Roots[]; // Stack roots (in-place array, so we pretend).
// };
- OpaqueType *RecursiveTy = OpaqueType::get();
-
+
+ StackEntryTy = StructType::create(M.getContext(), "gc_stackentry");
+
EltTys.clear();
- EltTys.push_back(PointerType::getUnqual(RecursiveTy));
+ EltTys.push_back(PointerType::getUnqual(StackEntryTy));
EltTys.push_back(FrameMapPtrTy);
- PATypeHolder LinkTyH = StructType::get(EltTys);
-
- RecursiveTy->refineAbstractTypeTo(LinkTyH.get());
- StackEntryTy = cast<StructType>(LinkTyH.get());
- const PointerType *StackEntryPtrTy = PointerType::getUnqual(StackEntryTy);
- M.addTypeName("gc_stackentry", LinkTyH.get()); // FIXME: Is this safe from
- // a FunctionPass?
+ StackEntryTy->setBody(EltTys);
+ PointerType *StackEntryPtrTy = PointerType::getUnqual(StackEntryTy);
// Get the root chain if it already exists.
Head = M.getGlobalVariable("llvm_gc_root_chain");
if (!Head) {
// If the root chain does not exist, insert a new one with linkonce
// linkage!
- Head = new GlobalVariable(StackEntryPtrTy, false,
- GlobalValue::LinkOnceLinkage,
+ Head = new GlobalVariable(M, StackEntryPtrTy, false,
+ GlobalValue::LinkOnceAnyLinkage,
Constant::getNullValue(StackEntryPtrTy),
- "llvm_gc_root_chain", &M);
+ "llvm_gc_root_chain");
} else if (Head->hasExternalLinkage() && Head->isDeclaration()) {
Head->setInitializer(Constant::getNullValue(StackEntryPtrTy));
- Head->setLinkage(GlobalValue::LinkOnceLinkage);
+ Head->setLinkage(GlobalValue::LinkOnceAnyLinkage);
}
return true;
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->getOperand(1)->stripPointerCasts()));
- if (IsNullValue(CI->getOperand(2)))
+ 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
MetaRoots.push_back(Pair);
}
GetElementPtrInst *
-ShadowStackGC::CreateGEP(IRBuilder<> &B, Value *BasePtr,
+ShadowStackGC::CreateGEP(LLVMContext &Context, IRBuilder<> &B, Value *BasePtr,
int Idx, int Idx2, const char *Name) {
- Value *Indices[] = { ConstantInt::get(Type::Int32Ty, 0),
- ConstantInt::get(Type::Int32Ty, Idx),
- ConstantInt::get(Type::Int32Ty, Idx2) };
- Value* Val = B.CreateGEP(BasePtr, Indices, Indices + 3, 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");
}
GetElementPtrInst *
-ShadowStackGC::CreateGEP(IRBuilder<> &B, Value *BasePtr,
+ShadowStackGC::CreateGEP(LLVMContext &Context, IRBuilder<> &B, Value *BasePtr,
int Idx, const char *Name) {
- Value *Indices[] = { ConstantInt::get(Type::Int32Ty, 0),
- ConstantInt::get(Type::Int32Ty, Idx) };
- Value *Val = B.CreateGEP(BasePtr, Indices, Indices + 2, 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");
/// runOnFunction - Insert code to maintain the shadow stack.
bool ShadowStackGC::performCustomLowering(Function &F) {
+ LLVMContext &Context = F.getContext();
+
// Find calls to llvm.gcroot.
CollectRoots(F);
// Build the constant map and figure the type of the shadow stack entry.
Value *FrameMap = GetFrameMap(F);
- const Type *ConcreteStackEntryTy = GetConcreteStackEntryType(F);
+ Type *ConcreteStackEntryTy = GetConcreteStackEntryType(F);
// Build the shadow stack entry at the very start of the function.
BasicBlock::iterator IP = F.getEntryBlock().begin();
// Initialize the map pointer and load the current head of the shadow stack.
Instruction *CurrentHead = AtEntry.CreateLoad(Head, "gc_currhead");
- Instruction *EntryMapPtr = CreateGEP(AtEntry, StackEntry,0,1,"gc_frame.map");
- AtEntry.CreateStore(FrameMap, EntryMapPtr);
+ Instruction *EntryMapPtr = CreateGEP(Context, AtEntry, StackEntry,
+ 0,1,"gc_frame.map");
+ AtEntry.CreateStore(FrameMap, EntryMapPtr);
// After all the allocas...
for (unsigned I = 0, E = Roots.size(); I != E; ++I) {
// For each root, find the corresponding slot in the aggregate...
- Value *SlotPtr = CreateGEP(AtEntry, StackEntry, 1 + I, "gc_root");
+ Value *SlotPtr = CreateGEP(Context, AtEntry, StackEntry, 1 + I, "gc_root");
// And use it in lieu of the alloca.
AllocaInst *OriginalAlloca = Roots[I].second;
AtEntry.SetInsertPoint(IP->getParent(), IP);
// Push the entry onto the shadow stack.
- Instruction *EntryNextPtr = CreateGEP(AtEntry,StackEntry,0,0,"gc_frame.next");
- Instruction *NewHeadVal = CreateGEP(AtEntry,StackEntry, 0, "gc_newhead");
- AtEntry.CreateStore(CurrentHead, EntryNextPtr);
- AtEntry.CreateStore(NewHeadVal, Head);
+ 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);
// For each instruction that escapes...
EscapeEnumerator EE(F, "gc_cleanup");
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(*AtExit, StackEntry, 0, 0,
+ Instruction *EntryNextPtr2 = CreateGEP(Context, *AtExit, StackEntry, 0, 0,
"gc_frame.next");
Value *SavedHead = AtExit->CreateLoad(EntryNextPtr2, "gc_savedhead");
AtExit->CreateStore(SavedHead, Head);