bool LowerInvoke::insertCheapEHSupport(Function &F) {
bool Changed = false;
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
SmallVector<Value*,16> CallArgs(II->op_begin(), II->op_end() - 3);
// Insert a normal call instruction...
CallInst *NewCall = CallInst::Create(II->getCalledValue(),
CallArgs, "", II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setAttributes(II->getAttributes());
NewCall->setDebugLoc(II->getDebugLoc());
II->replaceAllUsesWith(NewCall);
// Insert an unconditional branch to the normal destination.
BranchInst::Create(II->getNormalDest(), II);
// Remove any PHI node entries from the exception destination.
II->getUnwindDest()->removePredecessor(BB);
// Remove the invoke instruction now.
BB->getInstList().erase(II);
++NumInvokes; Changed = true;
}
return Changed;
}
// SimplifyFunction - Given information about callees, simplify the specified
// function if we have invokes to non-unwinding functions or code after calls to
// no-return functions.
bool PruneEH::SimplifyFunction(Function *F) {
bool MadeChange = false;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
if (II->doesNotThrow()) {
SmallVector<Value*, 8> Args(II->op_begin(), II->op_end() - 3);
// Insert a call instruction before the invoke.
CallInst *Call = CallInst::Create(II->getCalledValue(),
Args.begin(), Args.end(), "", II);
Call->takeName(II);
Call->setCallingConv(II->getCallingConv());
Call->setAttributes(II->getAttributes());
Call->setDebugLoc(II->getDebugLoc());
// Anything that used the value produced by the invoke instruction
// now uses the value produced by the call instruction. Note that we
// do this even for void functions and calls with no uses so that the
// callgraph edge is updated.
II->replaceAllUsesWith(Call);
BasicBlock *UnwindBlock = II->getUnwindDest();
UnwindBlock->removePredecessor(II->getParent());
// Insert a branch to the normal destination right before the
// invoke.
BranchInst::Create(II->getNormalDest(), II);
// Finally, delete the invoke instruction!
BB->getInstList().pop_back();
// If the unwind block is now dead, nuke it.
if (pred_begin(UnwindBlock) == pred_end(UnwindBlock))
DeleteBasicBlock(UnwindBlock); // Delete the new BB.
++NumRemoved;
MadeChange = true;
}
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; )
if (CallInst *CI = dyn_cast<CallInst>(I++))
if (CI->doesNotReturn() && !isa<UnreachableInst>(I)) {
// This call calls a function that cannot return. Insert an
// unreachable instruction after it and simplify the code. Do this
// by splitting the BB, adding the unreachable, then deleting the
// new BB.
BasicBlock *New = BB->splitBasicBlock(I);
// Remove the uncond branch and add an unreachable.
BB->getInstList().pop_back();
new UnreachableInst(BB->getContext(), BB);
DeleteBasicBlock(New); // Delete the new BB.
MadeChange = true;
++NumUnreach;
break;
}
}
return MadeChange;
}
// SimplifyFunction - Given information about callees, simplify the specified
// function if we have invokes to non-unwinding functions or code after calls to
// no-return functions.
bool PruneEH::SimplifyFunction(Function *F) {
CallGraph &CG = getAnalysis<CallGraph>();
bool MadeChange = false;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
if (Function *F = II->getCalledFunction())
if (DoesNotUnwind.count(CG[F])) {
SmallVector<Value*, 8> Args(II->op_begin()+3, II->op_end());
// Insert a call instruction before the invoke.
CallInst *Call = new CallInst(II->getCalledValue(),
&Args[0], Args.size(), "", II);
Call->takeName(II);
Call->setCallingConv(II->getCallingConv());
// Anything that used the value produced by the invoke instruction
// now uses the value produced by the call instruction.
II->replaceAllUsesWith(Call);
BasicBlock *UnwindBlock = II->getUnwindDest();
UnwindBlock->removePredecessor(II->getParent());
// Insert a branch to the normal destination right before the
// invoke.
new BranchInst(II->getNormalDest(), II);
// Finally, delete the invoke instruction!
BB->getInstList().pop_back();
// If the unwind block is now dead, nuke it.
if (pred_begin(UnwindBlock) == pred_end(UnwindBlock))
DeleteBasicBlock(UnwindBlock); // Delete the new BB.
++NumRemoved;
MadeChange = true;
}
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; )
if (CallInst *CI = dyn_cast<CallInst>(I++))
if (Function *Callee = CI->getCalledFunction())
if (DoesNotReturn.count(CG[Callee]) && !isa<UnreachableInst>(I)) {
// This call calls a function that cannot return. Insert an
// unreachable instruction after it and simplify the code. Do this
// by splitting the BB, adding the unreachable, then deleting the
// new BB.
BasicBlock *New = BB->splitBasicBlock(I);
// Remove the uncond branch and add an unreachable.
BB->getInstList().pop_back();
new UnreachableInst(BB);
DeleteBasicBlock(New); // Delete the new BB.
MadeChange = true;
++NumUnreach;
break;
}
}
return MadeChange;
}
virtual bool runOnFunction(Function &F) {
bool Modified = false;
for (Function::iterator I = F.begin(); I != F.end(); I++) {
BasicBlock *BB = I;
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
// Note: taking BI++ out of the for statement is important. Since this
// loop may delete the instruction at *BI, this will invalidate the
// iterator. So we make sure the iterator is incremented right from
// the start and it already points to the next instruction. This way,
// removing I from the basic block is harmless.
Instruction &I = *BI++;
// These nested conditions match a specific instruction pattern. We're
// looking for a load whose address is a GEP constant expression.
if (LoadInst *Load = dyn_cast<LoadInst>(&I)) {
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Load->getOperand(0))) {
if (GEPOperator *GEP = dyn_cast<GEPOperator>(CE)) {
Value *Ptr = GEP->getPointerOperand();
// Only look for accesses to threadIdx with the expected amount of
// GEP indices (essentially struct access to threadIdx.<member>.
if (Ptr->getName() != "threadIdx" || GEP->getNumIndices() != 2) {
continue;
}
// struct access as a GEP has two indices; read the LLVM
// documentation on GEPs if this doesn't make sense.
if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2))) {
// Choose a function based on the index.
uint64_t DimIndex = CI->getZExtValue();
Function *TargetFunc;
if (DimIndex == 0) {
TargetFunc = TidxRef;
} else if (DimIndex == 1) {
TargetFunc = TidyRef;
} else if (DimIndex == 2) {
TargetFunc = TidzRef;
} else {
report_fatal_error("Invalid index for threadIdx access");
}
// Create a call instruction to the appropriate _tid* function
// right before the load and replace the load by it.
CallInst *TidFuncCall = CallInst::Create(TargetFunc, "", Load);
TidFuncCall->takeName(Load);
Load->replaceAllUsesWith(TidFuncCall);
Load->eraseFromParent();
Modified = true;
}
}
}
}
}
}
return Modified;
}
Value *WebAssemblyLowerEmscriptenEHSjLj::wrapInvoke(CallOrInvoke *CI) {
LLVMContext &C = CI->getModule()->getContext();
// If we are calling a function that is noreturn, we must remove that
// attribute. The code we insert here does expect it to return, after we
// catch the exception.
if (CI->doesNotReturn()) {
if (auto *F = dyn_cast<Function>(CI->getCalledValue()))
F->removeFnAttr(Attribute::NoReturn);
CI->removeAttribute(AttributeList::FunctionIndex, Attribute::NoReturn);
}
IRBuilder<> IRB(C);
IRB.SetInsertPoint(CI);
// Pre-invoke
// __THREW__ = 0;
IRB.CreateStore(IRB.getInt32(0), ThrewGV);
// Invoke function wrapper in JavaScript
SmallVector<Value *, 16> Args;
// Put the pointer to the callee as first argument, so it can be called
// within the invoke wrapper later
Args.push_back(CI->getCalledValue());
Args.append(CI->arg_begin(), CI->arg_end());
CallInst *NewCall = IRB.CreateCall(getInvokeWrapper(CI), Args);
NewCall->takeName(CI);
NewCall->setCallingConv(CI->getCallingConv());
NewCall->setDebugLoc(CI->getDebugLoc());
// Because we added the pointer to the callee as first argument, all
// argument attribute indices have to be incremented by one.
SmallVector<AttributeSet, 8> ArgAttributes;
const AttributeList &InvokeAL = CI->getAttributes();
// No attributes for the callee pointer.
ArgAttributes.push_back(AttributeSet());
// Copy the argument attributes from the original
for (unsigned i = 0, e = CI->getNumArgOperands(); i < e; ++i)
ArgAttributes.push_back(InvokeAL.getParamAttributes(i));
// Reconstruct the AttributesList based on the vector we constructed.
AttributeList NewCallAL =
AttributeList::get(C, InvokeAL.getFnAttributes(),
InvokeAL.getRetAttributes(), ArgAttributes);
NewCall->setAttributes(NewCallAL);
CI->replaceAllUsesWith(NewCall);
// Post-invoke
// %__THREW__.val = __THREW__; __THREW__ = 0;
Value *Threw = IRB.CreateLoad(ThrewGV, ThrewGV->getName() + ".val");
IRB.CreateStore(IRB.getInt32(0), ThrewGV);
return Threw;
}
/// rewriteExpensiveInvoke - Insert code and hack the function to replace the
/// specified invoke instruction with a call.
void LowerInvoke::rewriteExpensiveInvoke(InvokeInst *II, unsigned InvokeNo,
AllocaInst *InvokeNum,
AllocaInst *StackPtr,
SwitchInst *CatchSwitch) {
ConstantInt *InvokeNoC = ConstantInt::get(Type::getInt32Ty(II->getContext()),
InvokeNo);
// If the unwind edge has phi nodes, split the edge.
if (isa<PHINode>(II->getUnwindDest()->begin())) {
SplitCriticalEdge(II, 1, this);
// If there are any phi nodes left, they must have a single predecessor.
while (PHINode *PN = dyn_cast<PHINode>(II->getUnwindDest()->begin())) {
PN->replaceAllUsesWith(PN->getIncomingValue(0));
PN->eraseFromParent();
}
}
// Insert a store of the invoke num before the invoke and store zero into the
// location afterward.
new StoreInst(InvokeNoC, InvokeNum, true, II); // volatile
// Insert a store of the stack ptr before the invoke, so we can restore it
// later in the exception case.
CallInst* StackSaveRet = CallInst::Create(StackSaveFn, "ssret", II);
new StoreInst(StackSaveRet, StackPtr, true, II); // volatile
BasicBlock::iterator NI = II->getNormalDest()->getFirstInsertionPt();
// nonvolatile.
new StoreInst(Constant::getNullValue(Type::getInt32Ty(II->getContext())),
InvokeNum, false, NI);
Instruction* StackPtrLoad =
new LoadInst(StackPtr, "stackptr.restore", true,
II->getUnwindDest()->getFirstInsertionPt());
CallInst::Create(StackRestoreFn, StackPtrLoad, "")->insertAfter(StackPtrLoad);
// Add a switch case to our unwind block.
CatchSwitch->addCase(InvokeNoC, II->getUnwindDest());
// Insert a normal call instruction.
SmallVector<Value*,16> CallArgs(II->op_begin(), II->op_end() - 3);
CallInst *NewCall = CallInst::Create(II->getCalledValue(),
CallArgs, "", II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setAttributes(II->getAttributes());
NewCall->setDebugLoc(II->getDebugLoc());
II->replaceAllUsesWith(NewCall);
// Replace the invoke with an uncond branch.
BranchInst::Create(II->getNormalDest(), NewCall->getParent());
II->eraseFromParent();
}
/// changeToCall - Convert the specified invoke into a normal call.
static void changeToCall(InvokeInst *II) {
SmallVector<Value*, 8> Args(II->op_begin(), II->op_end() - 3);
CallInst *NewCall = CallInst::Create(II->getCalledValue(), Args, "", II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setAttributes(II->getAttributes());
NewCall->setDebugLoc(II->getDebugLoc());
II->replaceAllUsesWith(NewCall);
// Follow the call by a branch to the normal destination.
BranchInst::Create(II->getNormalDest(), II);
// Update PHI nodes in the unwind destination
II->getUnwindDest()->removePredecessor(II->getParent());
II->eraseFromParent();
}
/// ChangeToCall - Convert the specified invoke into a normal call.
static void ChangeToCall(InvokeInst *II) {
BasicBlock *BB = II->getParent();
SmallVector<Value*, 8> Args(II->op_begin()+3, II->op_end());
CallInst *NewCall = CallInst::Create(II->getCalledValue(), Args.begin(),
Args.end(), "", II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setParamAttrs(II->getParamAttrs());
II->replaceAllUsesWith(NewCall);
// Follow the call by a branch to the normal destination.
BranchInst::Create(II->getNormalDest(), II);
// Update PHI nodes in the unwind destination
II->getUnwindDest()->removePredecessor(BB);
BB->getInstList().erase(II);
}
static void convertInvokeToCall(InvokeInst *Invoke) {
SmallVector<Value*, 16> CallArgs(Invoke->op_begin(), Invoke->op_end() - 3);
// Insert a normal call instruction.
CallInst *NewCall = CallInst::Create(Invoke->getCalledValue(),
CallArgs, "", Invoke);
CopyDebug(NewCall, Invoke);
NewCall->takeName(Invoke);
NewCall->setCallingConv(Invoke->getCallingConv());
NewCall->setAttributes(Invoke->getAttributes());
Invoke->replaceAllUsesWith(NewCall);
// Insert an unconditional branch to the normal destination.
BranchInst::Create(Invoke->getNormalDest(), Invoke);
// Remove any PHI node entries from the exception destination.
Invoke->getUnwindDest()->removePredecessor(Invoke->getParent());
Invoke->eraseFromParent();
}
bool LowerInvoke::insertCheapEHSupport(Function &F) {
bool Changed = false;
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
std::vector<Value*> CallArgs(II->op_begin()+3, II->op_end());
// Insert a normal call instruction...
CallInst *NewCall = CallInst::Create(II->getCalledValue(),
CallArgs.begin(), CallArgs.end(), "",II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setAttributes(II->getAttributes());
II->replaceAllUsesWith(NewCall);
// Insert an unconditional branch to the normal destination.
BranchInst::Create(II->getNormalDest(), II);
// Remove any PHI node entries from the exception destination.
II->getUnwindDest()->removePredecessor(BB);
// Remove the invoke instruction now.
BB->getInstList().erase(II);
++NumInvokes; Changed = true;
} else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
// Insert a new call to write(2, AbortMessage, AbortMessageLength);
writeAbortMessage(UI);
// Insert a call to abort()
CallInst::Create(AbortFn, "", UI)->setTailCall();
// Insert a return instruction. This really should be a "barrier", as it
// is unreachable.
ReturnInst::Create(F.getContext(),
F.getReturnType() == Type::getVoidTy(F.getContext()) ?
0 : Constant::getNullValue(F.getReturnType()), UI);
// Remove the unwind instruction now.
BB->getInstList().erase(UI);
++NumUnwinds; Changed = true;
}
return Changed;
}
/// rewriteExpensiveInvoke - Insert code and hack the function to replace the
/// specified invoke instruction with a call.
void LowerInvoke::rewriteExpensiveInvoke(InvokeInst *II, unsigned InvokeNo,
AllocaInst *InvokeNum,
SwitchInst *CatchSwitch) {
ConstantInt *InvokeNoC = ConstantInt::get(Type::getInt32Ty(II->getContext()),
InvokeNo);
// If the unwind edge has phi nodes, split the edge.
if (isa<PHINode>(II->getUnwindDest()->begin())) {
SplitCriticalEdge(II, 1, this);
// If there are any phi nodes left, they must have a single predecessor.
while (PHINode *PN = dyn_cast<PHINode>(II->getUnwindDest()->begin())) {
PN->replaceAllUsesWith(PN->getIncomingValue(0));
PN->eraseFromParent();
}
}
// Insert a store of the invoke num before the invoke and store zero into the
// location afterward.
new StoreInst(InvokeNoC, InvokeNum, true, II); // volatile
BasicBlock::iterator NI = II->getNormalDest()->getFirstNonPHI();
// nonvolatile.
new StoreInst(Constant::getNullValue(Type::getInt32Ty(II->getContext())),
InvokeNum, false, NI);
// Add a switch case to our unwind block.
CatchSwitch->addCase(InvokeNoC, II->getUnwindDest());
// Insert a normal call instruction.
std::vector<Value*> CallArgs(II->op_begin()+3, II->op_end());
CallInst *NewCall = CallInst::Create(II->getCalledValue(),
CallArgs.begin(), CallArgs.end(), "",
II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setAttributes(II->getAttributes());
II->replaceAllUsesWith(NewCall);
// Replace the invoke with an uncond branch.
BranchInst::Create(II->getNormalDest(), NewCall->getParent());
II->eraseFromParent();
}
void RewritePNaClLibraryCalls::rewriteSetjmpCall(CallInst *Call) {
// Find the intrinsic function.
Function *NaClSetjmpFunc = findSetjmpIntrinsic();
// Cast the jmp_buf argument to the type NaClSetjmpCall expects.
Type *PtrTy = NaClSetjmpFunc->getFunctionType()->getParamType(0);
BitCastInst *JmpBufCast = new BitCastInst(Call->getArgOperand(0), PtrTy,
"jmp_buf_i8", Call);
const DebugLoc &DLoc = Call->getDebugLoc();
JmpBufCast->setDebugLoc(DLoc);
// Emit the updated call.
Value *Args[] = { JmpBufCast };
CallInst *NaClSetjmpCall = CallInst::Create(NaClSetjmpFunc, Args, "", Call);
NaClSetjmpCall->setDebugLoc(DLoc);
NaClSetjmpCall->takeName(Call);
// Replace the original call.
Call->replaceAllUsesWith(NaClSetjmpCall);
Call->eraseFromParent();
}
bool LowerEmExceptions::runOnModule(Module &M) {
TheModule = &M;
// Add functions
Type *i32 = Type::getInt32Ty(M.getContext());
Type *i8 = Type::getInt8Ty(M.getContext());
Type *i1 = Type::getInt1Ty(M.getContext());
Type *i8P = i8->getPointerTo();
Type *Void = Type::getVoidTy(M.getContext());
if (!(GetHigh = TheModule->getFunction("getHigh32"))) {
FunctionType *GetHighFunc = FunctionType::get(i32, false);
GetHigh = Function::Create(GetHighFunc, GlobalValue::ExternalLinkage,
"getHigh32", TheModule);
}
if (!(PreInvoke = TheModule->getFunction("emscripten_preinvoke"))) {
FunctionType *VoidFunc = FunctionType::get(Void, false);
PreInvoke = Function::Create(VoidFunc, GlobalValue::ExternalLinkage, "emscripten_preinvoke", TheModule);
}
if (!(PostInvoke = TheModule->getFunction("emscripten_postinvoke"))) {
FunctionType *IntFunc = FunctionType::get(i32, false);
PostInvoke = Function::Create(IntFunc, GlobalValue::ExternalLinkage, "emscripten_postinvoke", TheModule);
}
FunctionType *LandingPadFunc = FunctionType::get(i8P, true);
LandingPad = Function::Create(LandingPadFunc, GlobalValue::ExternalLinkage, "emscripten_landingpad", TheModule);
FunctionType *ResumeFunc = FunctionType::get(Void, true);
Resume = Function::Create(ResumeFunc, GlobalValue::ExternalLinkage, "emscripten_resume", TheModule);
// Process
bool HasWhitelist = Whitelist.size() > 0;
std::string WhitelistChecker;
if (HasWhitelist) WhitelistChecker = "," + Whitelist + ",";
bool Changed = false;
for (Module::iterator Iter = M.begin(), E = M.end(); Iter != E; ) {
Function *F = Iter++;
std::vector<Instruction*> ToErase;
std::set<LandingPadInst*> LandingPads;
bool AllowExceptionsInFunc = !HasWhitelist || int(WhitelistChecker.find(F->getName())) > 0;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
// check terminator for invokes
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
LandingPads.insert(II->getLandingPadInst());
bool NeedInvoke = AllowExceptionsInFunc && canThrow(II->getCalledValue());
if (NeedInvoke) {
// Insert a normal call instruction folded in between pre- and post-invoke
CallInst::Create(PreInvoke, "", II);
SmallVector<Value*,16> CallArgs(II->op_begin(), II->op_end() - 3);
CallInst *NewCall = CallInst::Create(II->getCalledValue(),
CallArgs, "", II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setAttributes(II->getAttributes());
NewCall->setDebugLoc(II->getDebugLoc());
II->replaceAllUsesWith(NewCall);
ToErase.push_back(II);
CallInst *Post = CallInst::Create(PostInvoke, "", II);
Instruction *Post1 = new TruncInst(Post, i1, "", II);
// Insert a branch based on the postInvoke
BranchInst::Create(II->getUnwindDest(), II->getNormalDest(), Post1, II);
} else {
// This can't throw, and we don't need this invoke, just replace it with a call+branch
SmallVector<Value*,16> CallArgs(II->op_begin(), II->op_end() - 3);
CallInst *NewCall = CallInst::Create(II->getCalledValue(),
CallArgs, "", II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setAttributes(II->getAttributes());
NewCall->setDebugLoc(II->getDebugLoc());
II->replaceAllUsesWith(NewCall);
ToErase.push_back(II);
BranchInst::Create(II->getNormalDest(), II);
// Remove any PHI node entries from the exception destination.
II->getUnwindDest()->removePredecessor(BB);
}
Changed = true;
}
// scan the body of the basic block for resumes
for (BasicBlock::iterator Iter = BB->begin(), E = BB->end();
Iter != E; ) {
Instruction *I = Iter++;
if (ResumeInst *R = dyn_cast<ResumeInst>(I)) {
// split the input into legal values
Value *Input = R->getValue();
ExtractValueInst *Low = ExtractValueInst::Create(Input, 0, "", R);
ExtractValueInst *High = ExtractValueInst::Create(Input, 1, "", R);
// create a resume call
SmallVector<Value*,2> CallArgs;
CallArgs.push_back(Low);
CallArgs.push_back(High);
CallInst::Create(Resume, CallArgs, "", R);
new UnreachableInst(TheModule->getContext(), R); // add a terminator to the block
ToErase.push_back(R);
}
}
}
// Look for orphan landingpads, can occur in blocks with no predecesors
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
Instruction *I = BB->getFirstNonPHI();
if (LandingPadInst *LP = dyn_cast<LandingPadInst>(I)) {
LandingPads.insert(LP);
}
}
// Handle all the landingpad for this function together, as multiple invokes may share a single lp
for (std::set<LandingPadInst*>::iterator I = LandingPads.begin(); I != LandingPads.end(); I++) {
// Replace the landingpad with a landingpad call to get the low part, and a getHigh for the high
LandingPadInst *LP = *I;
unsigned Num = LP->getNumClauses();
SmallVector<Value*,16> NewLPArgs;
NewLPArgs.push_back(LP->getPersonalityFn());
for (unsigned i = 0; i < Num; i++) {
Value *Arg = LP->getClause(i);
// As a temporary workaround for the lack of aggregate varargs support
// in the varargs lowering code, break out filter operands into their
// component elements.
if (LP->isFilter(i)) {
ArrayType *ATy = cast<ArrayType>(Arg->getType());
for (unsigned elem = 0, elemEnd = ATy->getNumElements(); elem != elemEnd; ++elem) {
Instruction *EE = ExtractValueInst::Create(Arg, makeArrayRef(elem), "", LP);
NewLPArgs.push_back(EE);
}
} else {
NewLPArgs.push_back(Arg);
}
}
NewLPArgs.push_back(LP->isCleanup() ? ConstantInt::getTrue(i1) : ConstantInt::getFalse(i1));
CallInst *NewLP = CallInst::Create(LandingPad, NewLPArgs, "", LP);
Instruction *High = CallInst::Create(GetHigh, "", LP);
// New recreate an aggregate for them, which will be all simplified later (simplification cannot handle landingpad, hence all this)
InsertValueInst *IVA = InsertValueInst::Create(UndefValue::get(LP->getType()), NewLP, 0, "", LP);
InsertValueInst *IVB = InsertValueInst::Create(IVA, High, 1, "", LP);
LP->replaceAllUsesWith(IVB);
ToErase.push_back(LP);
}
// erase everything we no longer need in this function
for (unsigned i = 0; i < ToErase.size(); i++) ToErase[i]->eraseFromParent();
}
return Changed;
}
// Convert the given call to use normalized argument/return types.
template <class T> static bool ConvertCall(T *Call, Pass *P) {
// Don't try to change calls to intrinsics.
if (isa<IntrinsicInst>(Call))
return false;
FunctionType *FTy = cast<FunctionType>(
Call->getCalledValue()->getType()->getPointerElementType());
FunctionType *NFTy = NormalizeFunctionType(FTy);
if (NFTy == FTy)
return false; // No change needed.
// Convert arguments.
SmallVector<Value *, 8> Args;
for (unsigned I = 0; I < Call->getNumArgOperands(); ++I) {
Value *Arg = Call->getArgOperand(I);
if (NFTy->getParamType(I) != FTy->getParamType(I)) {
Instruction::CastOps CastType =
Call->getAttributes().hasAttribute(I + 1, Attribute::SExt) ?
Instruction::SExt : Instruction::ZExt;
Arg = CopyDebug(CastInst::Create(CastType, Arg, NFTy->getParamType(I),
"arg_ext", Call), Call);
}
Args.push_back(Arg);
}
Value *CastFunc =
CopyDebug(new BitCastInst(Call->getCalledValue(), NFTy->getPointerTo(),
Call->getName() + ".arg_cast", Call), Call);
Value *Result = NULL;
if (CallInst *OldCall = dyn_cast<CallInst>(Call)) {
CallInst *NewCall = CopyDebug(CallInst::Create(CastFunc, Args, "", OldCall),
OldCall);
NewCall->takeName(OldCall);
NewCall->setAttributes(OldCall->getAttributes());
NewCall->setCallingConv(OldCall->getCallingConv());
NewCall->setTailCall(OldCall->isTailCall());
Result = NewCall;
if (FTy->getReturnType() != NFTy->getReturnType()) {
Result = CopyDebug(new TruncInst(NewCall, FTy->getReturnType(),
NewCall->getName() + ".ret_trunc", Call),
Call);
}
} else if (InvokeInst *OldInvoke = dyn_cast<InvokeInst>(Call)) {
BasicBlock *Parent = OldInvoke->getParent();
BasicBlock *NormalDest = OldInvoke->getNormalDest();
BasicBlock *UnwindDest = OldInvoke->getUnwindDest();
if (FTy->getReturnType() != NFTy->getReturnType()) {
if (BasicBlock *SplitDest = SplitCriticalEdge(Parent, NormalDest)) {
NormalDest = SplitDest;
}
}
InvokeInst *New = CopyDebug(InvokeInst::Create(CastFunc, NormalDest,
UnwindDest, Args,
"", OldInvoke),
OldInvoke);
New->takeName(OldInvoke);
if (FTy->getReturnType() != NFTy->getReturnType()) {
Result = CopyDebug(new TruncInst(New, FTy->getReturnType(),
New->getName() + ".ret_trunc",
NormalDest->getTerminator()),
OldInvoke);
} else {
Result = New;
}
New->setAttributes(OldInvoke->getAttributes());
New->setCallingConv(OldInvoke->getCallingConv());
}
Call->replaceAllUsesWith(Result);
Call->eraseFromParent();
return true;
}
/// HandleCallsInBlockInlinedThroughInvoke - When we inline a basic block into
/// an invoke, we have to turn all of the calls that can throw into
/// invokes. This function analyze BB to see if there are any calls, and if so,
/// it rewrites them to be invokes that jump to InvokeDest and fills in the PHI
/// nodes in that block with the values specified in InvokeDestPHIValues.
///
/// Returns true to indicate that the next block should be skipped.
static bool HandleCallsInBlockInlinedThroughInvoke(BasicBlock *BB,
InvokeInliningInfo &Invoke) {
for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
Instruction *I = BBI++;
// We only need to check for function calls: inlined invoke
// instructions require no special handling.
CallInst *CI = dyn_cast<CallInst>(I);
if (CI == 0) continue;
// LIBUNWIND: merge selector instructions.
if (EHSelectorInst *Inner = dyn_cast<EHSelectorInst>(CI)) {
EHSelectorInst *Outer = Invoke.getOuterSelector();
if (!Outer) continue;
bool innerIsOnlyCleanup = isCleanupOnlySelector(Inner);
bool outerIsOnlyCleanup = isCleanupOnlySelector(Outer);
// If both selectors contain only cleanups, we don't need to do
// anything. TODO: this is really just a very specific instance
// of a much more general optimization.
if (innerIsOnlyCleanup && outerIsOnlyCleanup) continue;
// Otherwise, we just append the outer selector to the inner selector.
SmallVector<Value*, 16> NewSelector;
for (unsigned i = 0, e = Inner->getNumArgOperands(); i != e; ++i)
NewSelector.push_back(Inner->getArgOperand(i));
for (unsigned i = 2, e = Outer->getNumArgOperands(); i != e; ++i)
NewSelector.push_back(Outer->getArgOperand(i));
CallInst *NewInner =
IRBuilder<>(Inner).CreateCall(Inner->getCalledValue(), NewSelector);
// No need to copy attributes, calling convention, etc.
NewInner->takeName(Inner);
Inner->replaceAllUsesWith(NewInner);
Inner->eraseFromParent();
continue;
}
// If this call cannot unwind, don't convert it to an invoke.
if (CI->doesNotThrow())
continue;
// Convert this function call into an invoke instruction.
// First, split the basic block.
BasicBlock *Split = BB->splitBasicBlock(CI, CI->getName()+".noexc");
// Delete the unconditional branch inserted by splitBasicBlock
BB->getInstList().pop_back();
// LIBUNWIND: If this is a call to @llvm.eh.resume, just branch
// directly to the new landing pad.
if (Invoke.forwardEHResume(CI, BB)) {
// TODO: 'Split' is now unreachable; clean it up.
// We want to leave the original call intact so that the call
// graph and other structures won't get misled. We also have to
// avoid processing the next block, or we'll iterate here forever.
return true;
}
// Otherwise, create the new invoke instruction.
ImmutableCallSite CS(CI);
SmallVector<Value*, 8> InvokeArgs(CS.arg_begin(), CS.arg_end());
InvokeInst *II =
InvokeInst::Create(CI->getCalledValue(), Split,
Invoke.getOuterUnwindDest(),
InvokeArgs, CI->getName(), BB);
II->setCallingConv(CI->getCallingConv());
II->setAttributes(CI->getAttributes());
// Make sure that anything using the call now uses the invoke! This also
// updates the CallGraph if present, because it uses a WeakVH.
CI->replaceAllUsesWith(II);
Split->getInstList().pop_front(); // Delete the original call
// Update any PHI nodes in the exceptional block to indicate that
// there is now a new entry in them.
Invoke.addIncomingPHIValuesFor(BB);
return false;
}
return false;
}
bool WebAssemblyLowerEmscriptenEHSjLj::runEHOnFunction(Function &F) {
Module &M = *F.getParent();
LLVMContext &C = F.getContext();
IRBuilder<> IRB(C);
bool Changed = false;
SmallVector<Instruction *, 64> ToErase;
SmallPtrSet<LandingPadInst *, 32> LandingPads;
bool AllowExceptions =
areAllExceptionsAllowed() || EHWhitelistSet.count(F.getName());
for (BasicBlock &BB : F) {
auto *II = dyn_cast<InvokeInst>(BB.getTerminator());
if (!II)
continue;
Changed = true;
LandingPads.insert(II->getLandingPadInst());
IRB.SetInsertPoint(II);
bool NeedInvoke = AllowExceptions && canThrow(II->getCalledValue());
if (NeedInvoke) {
// Wrap invoke with invoke wrapper and generate preamble/postamble
Value *Threw = wrapInvoke(II);
ToErase.push_back(II);
// Insert a branch based on __THREW__ variable
Value *Cmp = IRB.CreateICmpEQ(Threw, IRB.getInt32(1), "cmp");
IRB.CreateCondBr(Cmp, II->getUnwindDest(), II->getNormalDest());
} else {
// This can't throw, and we don't need this invoke, just replace it with a
// call+branch
SmallVector<Value *, 16> Args(II->arg_begin(), II->arg_end());
CallInst *NewCall = IRB.CreateCall(II->getCalledValue(), Args);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setDebugLoc(II->getDebugLoc());
NewCall->setAttributes(II->getAttributes());
II->replaceAllUsesWith(NewCall);
ToErase.push_back(II);
IRB.CreateBr(II->getNormalDest());
// Remove any PHI node entries from the exception destination
II->getUnwindDest()->removePredecessor(&BB);
}
}
// Process resume instructions
for (BasicBlock &BB : F) {
// Scan the body of the basic block for resumes
for (Instruction &I : BB) {
auto *RI = dyn_cast<ResumeInst>(&I);
if (!RI)
continue;
// Split the input into legal values
Value *Input = RI->getValue();
IRB.SetInsertPoint(RI);
Value *Low = IRB.CreateExtractValue(Input, 0, "low");
// Create a call to __resumeException function
IRB.CreateCall(ResumeF, {Low});
// Add a terminator to the block
IRB.CreateUnreachable();
ToErase.push_back(RI);
}
}
// Process llvm.eh.typeid.for intrinsics
for (BasicBlock &BB : F) {
for (Instruction &I : BB) {
auto *CI = dyn_cast<CallInst>(&I);
if (!CI)
continue;
const Function *Callee = CI->getCalledFunction();
if (!Callee)
continue;
if (Callee->getIntrinsicID() != Intrinsic::eh_typeid_for)
continue;
IRB.SetInsertPoint(CI);
CallInst *NewCI =
IRB.CreateCall(EHTypeIDF, CI->getArgOperand(0), "typeid");
CI->replaceAllUsesWith(NewCI);
ToErase.push_back(CI);
}
}
// Look for orphan landingpads, can occur in blocks with no predecessors
for (BasicBlock &BB : F) {
Instruction *I = BB.getFirstNonPHI();
if (auto *LPI = dyn_cast<LandingPadInst>(I))
LandingPads.insert(LPI);
}
// Handle all the landingpad for this function together, as multiple invokes
// may share a single lp
for (LandingPadInst *LPI : LandingPads) {
IRB.SetInsertPoint(LPI);
SmallVector<Value *, 16> FMCArgs;
for (unsigned i = 0, e = LPI->getNumClauses(); i < e; ++i) {
Constant *Clause = LPI->getClause(i);
// As a temporary workaround for the lack of aggregate varargs support
// in the interface between JS and wasm, break out filter operands into
// their component elements.
if (LPI->isFilter(i)) {
auto *ATy = cast<ArrayType>(Clause->getType());
for (unsigned j = 0, e = ATy->getNumElements(); j < e; ++j) {
Value *EV = IRB.CreateExtractValue(Clause, makeArrayRef(j), "filter");
FMCArgs.push_back(EV);
}
} else
FMCArgs.push_back(Clause);
}
// Create a call to __cxa_find_matching_catch_N function
Function *FMCF = getFindMatchingCatch(M, FMCArgs.size());
CallInst *FMCI = IRB.CreateCall(FMCF, FMCArgs, "fmc");
Value *Undef = UndefValue::get(LPI->getType());
Value *Pair0 = IRB.CreateInsertValue(Undef, FMCI, 0, "pair0");
Value *TempRet0 =
IRB.CreateLoad(TempRet0GV, TempRet0GV->getName() + ".val");
Value *Pair1 = IRB.CreateInsertValue(Pair0, TempRet0, 1, "pair1");
LPI->replaceAllUsesWith(Pair1);
ToErase.push_back(LPI);
}
// Erase everything we no longer need in this function
for (Instruction *I : ToErase)
I->eraseFromParent();
return Changed;
}
CallGraphNode* ArgumentRecovery::recoverArguments(llvm::CallGraphNode *node)
{
Function* fn = node->getFunction();
if (fn == nullptr)
{
// "theoretical nodes", whatever that is
return nullptr;
}
// quick exit if there isn't exactly one argument
if (fn->arg_size() != 1)
{
return nullptr;
}
Argument* fnArg = fn->arg_begin();
if (!isStructType(fnArg))
{
return nullptr;
}
// This is a nasty NASTY hack that relies on the AA pass being RegisterUse.
// The data should be moved to a separate helper pass that can be queried from both the AA pass and this one.
RegisterUse& regUse = getAnalysis<RegisterUse>();
CallGraph& cg = getAnalysis<CallGraphWrapperPass>().getCallGraph();
const auto* modRefInfo = regUse.getModRefInfo(fn);
assert(modRefInfo != nullptr);
// At this point we pretty much know that we're going to modify the function, so start doing that.
// Get register offsets from the old function before we start mutilating it.
auto& registerMap = exposeAllRegisters(fn);
// Create a new function prototype, asking RegisterUse for which registers should be passed in, and how.
LLVMContext& ctx = fn->getContext();
SmallVector<pair<const char*, Type*>, 16> parameters;
Type* int64 = Type::getInt64Ty(ctx);
Type* int64ptr = Type::getInt64PtrTy(ctx);
for (const auto& pair : *modRefInfo)
{
if (pair.second != RegisterUse::NoModRef)
{
Type* paramType = (pair.second & RegisterUse::Mod) == RegisterUse::Mod ? int64ptr : int64;
parameters.push_back({pair.first, paramType});
}
}
// Order parameters.
// FIXME: This could use an ABI-specific sort routine. For now, use a lexicographical sort.
sort(parameters.begin(), parameters.end(), [](const pair<const char*, Type*>& a, const pair<const char*, Type*>& b) {
return strcmp(a.first, b.first) < 0;
});
// Extract parameter types.
SmallVector<Type*, 16> parameterTypes;
for (const auto& pair : parameters)
{
parameterTypes.push_back(pair.second);
}
// Ideally, we would also do caller analysis here to figure out which output registers are never read, such that
// we can either eliminate them from the parameter list or pass them by value instead of by address.
// We would also pick a return value.
FunctionType* newFunctionType = FunctionType::get(Type::getVoidTy(ctx), parameterTypes, false);
Function* newFunc = Function::Create(newFunctionType, fn->getLinkage());
newFunc->copyAttributesFrom(fn);
fn->getParent()->getFunctionList().insert(fn, newFunc);
newFunc->takeName(fn);
fn->setName("__hollow_husk__" + newFunc->getName());
// Set argument names
size_t i = 0;
for (Argument& arg : newFunc->args())
{
arg.setName(parameters[i].first);
i++;
}
// update call graph
CallGraphNode* newFuncNode = cg.getOrInsertFunction(newFunc);
CallGraphNode* oldFuncNode = cg[fn];
// loop over callers and transform call sites.
while (!fn->use_empty())
{
CallSite cs(fn->user_back());
Instruction* call = cast<CallInst>(cs.getInstruction());
Function* caller = call->getParent()->getParent();
auto& registerPositions = exposeAllRegisters(caller);
SmallVector<Value*, 16> callParameters;
for (const auto& pair : parameters)
{
// HACKHACK: find a pointer to a 64-bit int in the set.
Value* registerPointer = nullptr;
auto range = registerPositions.equal_range(pair.first);
for (auto iter = range.first; iter != range.second; iter++)
{
if (auto gep = dyn_cast<GetElementPtrInst>(iter->second))
if (gep->getResultElementType() == int64)
{
registerPointer = gep;
break;
}
}
assert(registerPointer != nullptr);
if (isa<PointerType>(pair.second))
{
callParameters.push_back(registerPointer);
}
else
{
// Create a load instruction. GVN will get rid of it if it's unnecessary.
LoadInst* load = new LoadInst(registerPointer, pair.first, call);
callParameters.push_back(load);
}
}
CallInst* newCall = CallInst::Create(newFunc, callParameters, "", call);
// Update AA
regUse.replaceWithNewValue(call, newCall);
// Update call graph
CallGraphNode* calleeNode = cg[caller];
calleeNode->replaceCallEdge(cs, CallSite(newCall), newFuncNode);
// Finish replacing
if (!call->use_empty())
{
call->replaceAllUsesWith(newCall);
newCall->takeName(call);
}
call->eraseFromParent();
}
// Do not fix functions without a body.
if (!fn->isDeclaration())
{
// Fix up function code. Start by moving everything into the new function.
newFunc->getBasicBlockList().splice(newFunc->begin(), fn->getBasicBlockList());
newFuncNode->stealCalledFunctionsFrom(oldFuncNode);
// Change register uses
size_t argIndex = 0;
auto& argList = newFunc->getArgumentList();
// Create a temporary insertion point. We don't want an existing instruction since chances are that we'll remove it.
Instruction* insertionPoint = BinaryOperator::CreateAdd(ConstantInt::get(int64, 0), ConstantInt::get(int64, 0), "noop", newFunc->begin()->begin());
for (auto iter = argList.begin(); iter != argList.end(); iter++, argIndex++)
{
Value* replaceWith = iter;
const auto& paramTuple = parameters[argIndex];
if (!isa<PointerType>(paramTuple.second))
{
// Create an alloca, copy value from parameter, replace GEP with alloca.
// This is ugly code gen, but it will optimize easily, and still work if
// we need a pointer reference to the register.
auto alloca = new AllocaInst(paramTuple.second, paramTuple.first, insertionPoint);
new StoreInst(iter, alloca, insertionPoint);
replaceWith = alloca;
}
// Replace all uses with new instance.
auto iterPair = registerMap.equal_range(paramTuple.first);
for (auto registerMapIter = iterPair.first; registerMapIter != iterPair.second; registerMapIter++)
{
auto& registerValue = registerMapIter->second;
registerValue->replaceAllUsesWith(replaceWith);
cast<Instruction>(registerValue)->eraseFromParent();
registerValue = replaceWith;
}
}
// At this point, the uses of the argument struct left should be:
// * preserved registers
// * indirect jumps
const auto& target = getAnalysis<TargetInfo>();
while (!fnArg->use_empty())
{
auto lastUser = fnArg->user_back();
if (auto user = dyn_cast<GetElementPtrInst>(lastUser))
{
// Promote register to alloca.
const char* maybeName = target.registerName(*user);
const char* regName = target.largestOverlappingRegister(maybeName);
assert(regName != nullptr);
auto alloca = new AllocaInst(user->getResultElementType(), regName, insertionPoint);
user->replaceAllUsesWith(alloca);
user->eraseFromParent();
}
else
{
auto call = cast<CallInst>(lastUser);
Function* intrin = nullptr;
StringRef intrinName = call->getCalledFunction()->getName();
if (intrinName == "x86_jump_intrin")
{
intrin = indirectJump;
}
else if (intrinName == "x86_call_intrin")
{
intrin = indirectCall;
}
else
{
assert(false);
// Can't decompile this function. Delete its body.
newFunc->deleteBody();
insertionPoint = nullptr;
break;
}
// Replace intrinsic with another intrinsic.
Value* jumpTarget = call->getOperand(2);
SmallVector<Value*, 16> callArgs;
callArgs.push_back(jumpTarget);
for (Argument& arg : argList)
{
callArgs.push_back(&arg);
}
CallInst* varargCall = CallInst::Create(intrin, callArgs, "", call);
newFuncNode->replaceCallEdge(CallSite(call), CallSite(varargCall), cg[intrin]);
regUse.replaceWithNewValue(call, varargCall);
varargCall->takeName(call);
call->eraseFromParent();
}
}
if (insertionPoint != nullptr)
{
// no longer needed
insertionPoint->eraseFromParent();
}
}
// At this point nothing should be using the old register argument anymore. (Pray!)
// Leave the hollow husk of the old function in place to be erased by global DCE.
registerAddresses[newFunc] = move(registerMap);
registerAddresses.erase(fn);
// Should be all.
return newFuncNode;
}