/// DoPromotion - This method actually performs the promotion of the specified /// arguments, and returns the new function. At this point, we know that it's /// safe to do so. CallGraphNode *ArgPromotion::DoPromotion(Function *F, SmallPtrSet<Argument*, 8> &ArgsToPromote, SmallPtrSet<Argument*, 8> &ByValArgsToTransform) { // Start by computing a new prototype for the function, which is the same as // the old function, but has modified arguments. const FunctionType *FTy = F->getFunctionType(); std::vector<const Type*> Params; typedef std::set<IndicesVector> ScalarizeTable; // ScalarizedElements - If we are promoting a pointer that has elements // accessed out of it, keep track of which elements are accessed so that we // can add one argument for each. // // Arguments that are directly loaded will have a zero element value here, to // handle cases where there are both a direct load and GEP accesses. // std::map<Argument*, ScalarizeTable> ScalarizedElements; // OriginalLoads - Keep track of a representative load instruction from the // original function so that we can tell the alias analysis implementation // what the new GEP/Load instructions we are inserting look like. std::map<IndicesVector, LoadInst*> OriginalLoads; // Attributes - Keep track of the parameter attributes for the arguments // that we are *not* promoting. For the ones that we do promote, the parameter // attributes are lost SmallVector<AttributeWithIndex, 8> AttributesVec; const AttrListPtr &PAL = F->getAttributes(); // Add any return attributes. if (Attributes attrs = PAL.getRetAttributes()) AttributesVec.push_back(AttributeWithIndex::get(0, attrs)); // First, determine the new argument list unsigned ArgIndex = 1; for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I, ++ArgIndex) { if (ByValArgsToTransform.count(I)) { // Simple byval argument? Just add all the struct element types. const Type *AgTy = cast<PointerType>(I->getType())->getElementType(); const StructType *STy = cast<StructType>(AgTy); for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) Params.push_back(STy->getElementType(i)); ++NumByValArgsPromoted; } else if (!ArgsToPromote.count(I)) { // Unchanged argument Params.push_back(I->getType()); if (Attributes attrs = PAL.getParamAttributes(ArgIndex)) AttributesVec.push_back(AttributeWithIndex::get(Params.size(), attrs)); } else if (I->use_empty()) { // Dead argument (which are always marked as promotable) ++NumArgumentsDead; } else { // Okay, this is being promoted. This means that the only uses are loads // or GEPs which are only used by loads // In this table, we will track which indices are loaded from the argument // (where direct loads are tracked as no indices). ScalarizeTable &ArgIndices = ScalarizedElements[I]; for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; ++UI) { Instruction *User = cast<Instruction>(*UI); assert(isa<LoadInst>(User) || isa<GetElementPtrInst>(User)); IndicesVector Indices; Indices.reserve(User->getNumOperands() - 1); // Since loads will only have a single operand, and GEPs only a single // non-index operand, this will record direct loads without any indices, // and gep+loads with the GEP indices. for (User::op_iterator II = User->op_begin() + 1, IE = User->op_end(); II != IE; ++II) Indices.push_back(cast<ConstantInt>(*II)->getSExtValue()); // GEPs with a single 0 index can be merged with direct loads if (Indices.size() == 1 && Indices.front() == 0) Indices.clear(); ArgIndices.insert(Indices); LoadInst *OrigLoad; if (LoadInst *L = dyn_cast<LoadInst>(User)) OrigLoad = L; else // Take any load, we will use it only to update Alias Analysis OrigLoad = cast<LoadInst>(User->use_back()); OriginalLoads[Indices] = OrigLoad; } // Add a parameter to the function for each element passed in. for (ScalarizeTable::iterator SI = ArgIndices.begin(), E = ArgIndices.end(); SI != E; ++SI) { // not allowed to dereference ->begin() if size() is 0 Params.push_back(GetElementPtrInst::getIndexedType(I->getType(), SI->begin(), SI->end())); assert(Params.back()); } if (ArgIndices.size() == 1 && ArgIndices.begin()->empty()) ++NumArgumentsPromoted; else ++NumAggregatesPromoted; } } // Add any function attributes. if (Attributes attrs = PAL.getFnAttributes()) AttributesVec.push_back(AttributeWithIndex::get(~0, attrs)); const Type *RetTy = FTy->getReturnType(); // Work around LLVM bug PR56: the CWriter cannot emit varargs functions which // have zero fixed arguments. bool ExtraArgHack = false; if (Params.empty() && FTy->isVarArg()) { ExtraArgHack = true; Params.push_back(Type::getInt32Ty(F->getContext())); } // Construct the new function type using the new arguments. FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg()); // Create the new function body and insert it into the module. Function *NF = Function::Create(NFTy, F->getLinkage(), F->getName()); NF->copyAttributesFrom(F); DEBUG(dbgs() << "ARG PROMOTION: Promoting to:" << *NF << "\n" << "From: " << *F); // Recompute the parameter attributes list based on the new arguments for // the function. NF->setAttributes(AttrListPtr::get(AttributesVec.begin(), AttributesVec.end())); AttributesVec.clear(); F->getParent()->getFunctionList().insert(F, NF); NF->takeName(F); // Get the alias analysis information that we need to update to reflect our // changes. AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); // Get the callgraph information that we need to update to reflect our // changes. CallGraph &CG = getAnalysis<CallGraph>(); // Get a new callgraph node for NF. CallGraphNode *NF_CGN = CG.getOrInsertFunction(NF); // Loop over all of the callers of the function, transforming the call sites // to pass in the loaded pointers. // SmallVector<Value*, 16> Args; while (!F->use_empty()) { CallSite CS = CallSite::get(F->use_back()); assert(CS.getCalledFunction() == F); Instruction *Call = CS.getInstruction(); const AttrListPtr &CallPAL = CS.getAttributes(); // Add any return attributes. if (Attributes attrs = CallPAL.getRetAttributes()) AttributesVec.push_back(AttributeWithIndex::get(0, attrs)); // Loop over the operands, inserting GEP and loads in the caller as // appropriate. CallSite::arg_iterator AI = CS.arg_begin(); ArgIndex = 1; for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I, ++AI, ++ArgIndex) if (!ArgsToPromote.count(I) && !ByValArgsToTransform.count(I)) { Args.push_back(*AI); // Unmodified argument if (Attributes Attrs = CallPAL.getParamAttributes(ArgIndex)) AttributesVec.push_back(AttributeWithIndex::get(Args.size(), Attrs)); } else if (ByValArgsToTransform.count(I)) { // Emit a GEP and load for each element of the struct. const Type *AgTy = cast<PointerType>(I->getType())->getElementType(); const StructType *STy = cast<StructType>(AgTy); Value *Idxs[2] = { ConstantInt::get(Type::getInt32Ty(F->getContext()), 0), 0 }; for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { Idxs[1] = ConstantInt::get(Type::getInt32Ty(F->getContext()), i); Value *Idx = GetElementPtrInst::Create(*AI, Idxs, Idxs+2, (*AI)->getName()+"."+utostr(i), Call); // TODO: Tell AA about the new values? Args.push_back(new LoadInst(Idx, Idx->getName()+".val", Call)); } } else if (!I->use_empty()) { // Non-dead argument: insert GEPs and loads as appropriate. ScalarizeTable &ArgIndices = ScalarizedElements[I]; // Store the Value* version of the indices in here, but declare it now // for reuse. std::vector<Value*> Ops; for (ScalarizeTable::iterator SI = ArgIndices.begin(), E = ArgIndices.end(); SI != E; ++SI) { Value *V = *AI; LoadInst *OrigLoad = OriginalLoads[*SI]; if (!SI->empty()) { Ops.reserve(SI->size()); const Type *ElTy = V->getType(); for (IndicesVector::const_iterator II = SI->begin(), IE = SI->end(); II != IE; ++II) { // Use i32 to index structs, and i64 for others (pointers/arrays). // This satisfies GEP constraints. const Type *IdxTy = (ElTy->isStructTy() ? Type::getInt32Ty(F->getContext()) : Type::getInt64Ty(F->getContext())); Ops.push_back(ConstantInt::get(IdxTy, *II)); // Keep track of the type we're currently indexing. ElTy = cast<CompositeType>(ElTy)->getTypeAtIndex(*II); } // And create a GEP to extract those indices. V = GetElementPtrInst::Create(V, Ops.begin(), Ops.end(), V->getName()+".idx", Call); Ops.clear(); AA.copyValue(OrigLoad->getOperand(0), V); } // Since we're replacing a load make sure we take the alignment // of the previous load. LoadInst *newLoad = new LoadInst(V, V->getName()+".val", Call); newLoad->setAlignment(OrigLoad->getAlignment()); Args.push_back(newLoad); AA.copyValue(OrigLoad, Args.back()); } } if (ExtraArgHack) Args.push_back(Constant::getNullValue(Type::getInt32Ty(F->getContext()))); // Push any varargs arguments on the list. for (; AI != CS.arg_end(); ++AI, ++ArgIndex) { Args.push_back(*AI); if (Attributes Attrs = CallPAL.getParamAttributes(ArgIndex)) AttributesVec.push_back(AttributeWithIndex::get(Args.size(), Attrs)); } // Add any function attributes. if (Attributes attrs = CallPAL.getFnAttributes()) AttributesVec.push_back(AttributeWithIndex::get(~0, attrs)); Instruction *New; if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) { New = InvokeInst::Create(NF, II->getNormalDest(), II->getUnwindDest(), Args.begin(), Args.end(), "", Call); cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv()); cast<InvokeInst>(New)->setAttributes(AttrListPtr::get(AttributesVec.begin(), AttributesVec.end())); } else { New = CallInst::Create(NF, Args.begin(), Args.end(), "", Call); cast<CallInst>(New)->setCallingConv(CS.getCallingConv()); cast<CallInst>(New)->setAttributes(AttrListPtr::get(AttributesVec.begin(), AttributesVec.end())); if (cast<CallInst>(Call)->isTailCall()) cast<CallInst>(New)->setTailCall(); } Args.clear(); AttributesVec.clear(); // Update the alias analysis implementation to know that we are replacing // the old call with a new one. AA.replaceWithNewValue(Call, New); // Update the callgraph to know that the callsite has been transformed. CallGraphNode *CalleeNode = CG[Call->getParent()->getParent()]; CalleeNode->replaceCallEdge(Call, New, NF_CGN); if (!Call->use_empty()) { Call->replaceAllUsesWith(New); New->takeName(Call); } // Finally, remove the old call from the program, reducing the use-count of // F. Call->eraseFromParent(); } // Since we have now created the new function, splice the body of the old // function right into the new function, leaving the old rotting hulk of the // function empty. NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList()); // Loop over the argument list, transfering uses of the old arguments over to // the new arguments, also transfering over the names as well. // for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(), I2 = NF->arg_begin(); I != E; ++I) { if (!ArgsToPromote.count(I) && !ByValArgsToTransform.count(I)) { // If this is an unmodified argument, move the name and users over to the // new version. I->replaceAllUsesWith(I2); I2->takeName(I); AA.replaceWithNewValue(I, I2); ++I2; continue; } if (ByValArgsToTransform.count(I)) { // In the callee, we create an alloca, and store each of the new incoming // arguments into the alloca. Instruction *InsertPt = NF->begin()->begin(); // Just add all the struct element types. const Type *AgTy = cast<PointerType>(I->getType())->getElementType(); Value *TheAlloca = new AllocaInst(AgTy, 0, "", InsertPt); const StructType *STy = cast<StructType>(AgTy); Value *Idxs[2] = { ConstantInt::get(Type::getInt32Ty(F->getContext()), 0), 0 }; for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { Idxs[1] = ConstantInt::get(Type::getInt32Ty(F->getContext()), i); Value *Idx = GetElementPtrInst::Create(TheAlloca, Idxs, Idxs+2, TheAlloca->getName()+"."+Twine(i), InsertPt); I2->setName(I->getName()+"."+Twine(i)); new StoreInst(I2++, Idx, InsertPt); } // Anything that used the arg should now use the alloca. I->replaceAllUsesWith(TheAlloca); TheAlloca->takeName(I); AA.replaceWithNewValue(I, TheAlloca); continue; } if (I->use_empty()) { AA.deleteValue(I); continue; } // Otherwise, if we promoted this argument, then all users are load // instructions (or GEPs with only load users), and all loads should be // using the new argument that we added. ScalarizeTable &ArgIndices = ScalarizedElements[I]; while (!I->use_empty()) { if (LoadInst *LI = dyn_cast<LoadInst>(I->use_back())) { assert(ArgIndices.begin()->empty() && "Load element should sort to front!"); I2->setName(I->getName()+".val"); LI->replaceAllUsesWith(I2); AA.replaceWithNewValue(LI, I2); LI->eraseFromParent(); DEBUG(dbgs() << "*** Promoted load of argument '" << I->getName() << "' in function '" << F->getName() << "'\n"); } else { GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->use_back()); IndicesVector Operands; Operands.reserve(GEP->getNumIndices()); for (User::op_iterator II = GEP->idx_begin(), IE = GEP->idx_end(); II != IE; ++II) Operands.push_back(cast<ConstantInt>(*II)->getSExtValue()); // GEPs with a single 0 index can be merged with direct loads if (Operands.size() == 1 && Operands.front() == 0) Operands.clear(); Function::arg_iterator TheArg = I2; for (ScalarizeTable::iterator It = ArgIndices.begin(); *It != Operands; ++It, ++TheArg) { assert(It != ArgIndices.end() && "GEP not handled??"); } std::string NewName = I->getName(); for (unsigned i = 0, e = Operands.size(); i != e; ++i) { NewName += "." + utostr(Operands[i]); } NewName += ".val"; TheArg->setName(NewName); DEBUG(dbgs() << "*** Promoted agg argument '" << TheArg->getName() << "' of function '" << NF->getName() << "'\n"); // All of the uses must be load instructions. Replace them all with // the argument specified by ArgNo. while (!GEP->use_empty()) { LoadInst *L = cast<LoadInst>(GEP->use_back()); L->replaceAllUsesWith(TheArg); AA.replaceWithNewValue(L, TheArg); L->eraseFromParent(); } AA.deleteValue(GEP); GEP->eraseFromParent(); } } // Increment I2 past all of the arguments added for this promoted pointer. for (unsigned i = 0, e = ArgIndices.size(); i != e; ++i) ++I2; } // Notify the alias analysis implementation that we inserted a new argument. if (ExtraArgHack) AA.copyValue(Constant::getNullValue(Type::getInt32Ty(F->getContext())), NF->arg_begin()); // Tell the alias analysis that the old function is about to disappear. AA.replaceWithNewValue(F, NF); NF_CGN->stealCalledFunctionsFrom(CG[F]); // Now that the old function is dead, delete it. If there is a dangling // reference to the CallgraphNode, just leave the dead function around for // someone else to nuke. CallGraphNode *CGN = CG[F]; if (CGN->getNumReferences() == 0) delete CG.removeFunctionFromModule(CGN); else F->setLinkage(Function::ExternalLinkage); return NF_CGN; }
void llvm::InsertProfilingInitCall(Function *MainFn, const char *FnName, GlobalValue *Array) { const Type *ArgVTy = PointerType::getUnqual(PointerType::getUnqual(Type::Int8Ty)); const PointerType *UIntPtr = PointerType::getUnqual(Type::Int32Ty); Module &M = *MainFn->getParent(); Constant *InitFn = M.getOrInsertFunction(FnName, Type::Int32Ty, Type::Int32Ty, ArgVTy, UIntPtr, Type::Int32Ty, (Type *)0); // This could force argc and argv into programs that wouldn't otherwise have // them, but instead we just pass null values in. std::vector<Value*> Args(4); Args[0] = Constant::getNullValue(Type::Int32Ty); Args[1] = Constant::getNullValue(ArgVTy); // Skip over any allocas in the entry block. BasicBlock *Entry = MainFn->begin(); BasicBlock::iterator InsertPos = Entry->begin(); while (isa<AllocaInst>(InsertPos)) ++InsertPos; std::vector<Constant*> GEPIndices(2, Constant::getNullValue(Type::Int32Ty)); unsigned NumElements = 0; if (Array) { Args[2] = ConstantExpr::getGetElementPtr(Array, &GEPIndices[0], GEPIndices.size()); NumElements = cast<ArrayType>(Array->getType()->getElementType())->getNumElements(); } else { // If this profiling instrumentation doesn't have a constant array, just // pass null. Args[2] = ConstantPointerNull::get(UIntPtr); } Args[3] = ConstantInt::get(Type::Int32Ty, NumElements); Instruction *InitCall = CallInst::Create(InitFn, Args.begin(), Args.end(), "newargc", InsertPos); // If argc or argv are not available in main, just pass null values in. Function::arg_iterator AI; switch (MainFn->arg_size()) { default: case 2: AI = MainFn->arg_begin(); ++AI; if (AI->getType() != ArgVTy) { Instruction::CastOps opcode = CastInst::getCastOpcode(AI, false, ArgVTy, false); InitCall->setOperand(2, CastInst::create(opcode, AI, ArgVTy, "argv.cast", InitCall)); } else { InitCall->setOperand(2, AI); } /* FALL THROUGH */ case 1: AI = MainFn->arg_begin(); // If the program looked at argc, have it look at the return value of the // init call instead. if (AI->getType() != Type::Int32Ty) { Instruction::CastOps opcode; if (!AI->use_empty()) { opcode = CastInst::getCastOpcode(InitCall, true, AI->getType(), true); AI->replaceAllUsesWith( CastInst::create(opcode, InitCall, AI->getType(), "", InsertPos)); } opcode = CastInst::getCastOpcode(AI, true, Type::Int32Ty, true); InitCall->setOperand(1, CastInst::create(opcode, AI, Type::Int32Ty, "argc.cast", InitCall)); } else { AI->replaceAllUsesWith(InitCall); InitCall->setOperand(1, AI); } case 0: break; } }
/// PropagateConstantsIntoArguments - Look at all uses of the specified /// function. If all uses are direct call sites, and all pass a particular /// constant in for an argument, propagate that constant in as the argument. /// bool IPCP::PropagateConstantsIntoArguments(Function &F) { if (F.arg_empty() || F.use_empty()) return false; // No arguments? Early exit. // For each argument, keep track of its constant value and whether it is a // constant or not. The bool is driven to true when found to be non-constant. SmallVector<std::pair<Constant*, bool>, 16> ArgumentConstants; ArgumentConstants.resize(F.arg_size()); unsigned NumNonconstant = 0; for (Value::use_iterator UI = F.use_begin(), E = F.use_end(); UI != E; ++UI) { User *U = *UI; // Ignore blockaddress uses. if (isa<BlockAddress>(U)) continue; // Used by a non-instruction, or not the callee of a function, do not // transform. if (!isa<CallInst>(U) && !isa<InvokeInst>(U)) return false; CallSite CS(cast<Instruction>(U)); if (!CS.isCallee(UI)) return false; // Check out all of the potentially constant arguments. Note that we don't // inspect varargs here. CallSite::arg_iterator AI = CS.arg_begin(); Function::arg_iterator Arg = F.arg_begin(); for (unsigned i = 0, e = ArgumentConstants.size(); i != e; ++i, ++AI, ++Arg) { // If this argument is known non-constant, ignore it. if (ArgumentConstants[i].second) continue; Constant *C = dyn_cast<Constant>(*AI); if (C && ArgumentConstants[i].first == 0) { ArgumentConstants[i].first = C; // First constant seen. } else if (C && ArgumentConstants[i].first == C) { // Still the constant value we think it is. } else if (*AI == &*Arg) { // Ignore recursive calls passing argument down. } else { // Argument became non-constant. If all arguments are non-constant now, // give up on this function. if (++NumNonconstant == ArgumentConstants.size()) return false; ArgumentConstants[i].second = true; } } } // If we got to this point, there is a constant argument! assert(NumNonconstant != ArgumentConstants.size()); bool MadeChange = false; Function::arg_iterator AI = F.arg_begin(); for (unsigned i = 0, e = ArgumentConstants.size(); i != e; ++i, ++AI) { // Do we have a constant argument? if (ArgumentConstants[i].second || AI->use_empty() || (AI->hasByValAttr() && !F.onlyReadsMemory())) continue; Value *V = ArgumentConstants[i].first; if (V == 0) V = UndefValue::get(AI->getType()); AI->replaceAllUsesWith(V); ++NumArgumentsProped; MadeChange = true; } return MadeChange; }
// // Method: runOnModule() // // Description: // Entry point for this LLVM pass. // Clone functions that take GEPs as arguments // // Inputs: // M - A reference to the LLVM module to transform // // Outputs: // M - The transformed LLVM module. // // Return value: // true - The module was modified. // false - The module was not modified. // bool GEPExprArgs::runOnModule(Module& M) { bool changed; do { changed = false; for (Module::iterator F = M.begin(); F != M.end(); ++F){ for (Function::iterator B = F->begin(), FE = F->end(); B != FE; ++B) { for (BasicBlock::iterator I = B->begin(), BE = B->end(); I != BE;) { CallInst *CI = dyn_cast<CallInst>(I++); if(!CI) continue; if(CI->hasByValArgument()) continue; // if the GEP calls a function, that is externally defined, // or might be changed, ignore this call site. Function *F = CI->getCalledFunction(); if (!F || (F->isDeclaration() || F->mayBeOverridden())) continue; if(F->hasStructRetAttr()) continue; if(F->isVarArg()) continue; // find the argument we must replace Function::arg_iterator ai = F->arg_begin(), ae = F->arg_end(); unsigned argNum = 1; for(; argNum < CI->getNumOperands();argNum++, ++ai) { if(ai->use_empty()) continue; if (isa<GEPOperator>(CI->getOperand(argNum))) break; } // if no argument was a GEP operator to be changed if(ai == ae) continue; GEPOperator *GEP = dyn_cast<GEPOperator>(CI->getOperand(argNum)); if(!GEP->hasAllConstantIndices()) continue; // Construct the new Type // Appends the struct Type at the beginning std::vector<Type*>TP; TP.push_back(GEP->getPointerOperand()->getType()); for(unsigned c = 1; c < CI->getNumOperands();c++) { TP.push_back(CI->getOperand(c)->getType()); } //return type is same as that of original instruction FunctionType *NewFTy = FunctionType::get(CI->getType(), TP, false); Function *NewF; numSimplified++; if(numSimplified > 800) return true; NewF = Function::Create(NewFTy, GlobalValue::InternalLinkage, F->getName().str() + ".TEST", &M); Function::arg_iterator NI = NewF->arg_begin(); NI->setName("GEParg"); ++NI; ValueToValueMapTy ValueMap; for (Function::arg_iterator II = F->arg_begin(); NI != NewF->arg_end(); ++II, ++NI) { ValueMap[II] = NI; NI->setName(II->getName()); NI->addAttr(F->getAttributes().getParamAttributes(II->getArgNo() + 1)); } NewF->setAttributes(NewF->getAttributes().addAttr( 0, F->getAttributes().getRetAttributes())); // Perform the cloning. SmallVector<ReturnInst*,100> Returns; CloneFunctionInto(NewF, F, ValueMap, false, Returns); std::vector<Value*> fargs; for(Function::arg_iterator ai = NewF->arg_begin(), ae= NewF->arg_end(); ai != ae; ++ai) { fargs.push_back(ai); } NewF->setAttributes(NewF->getAttributes().addAttr( ~0, F->getAttributes().getFnAttributes())); //Get the point to insert the GEP instr. SmallVector<Value*, 8> Ops(CI->op_begin()+1, CI->op_end()); Instruction *InsertPoint; for (BasicBlock::iterator insrt = NewF->front().begin(); isa<AllocaInst>(InsertPoint = insrt); ++insrt) {;} NI = NewF->arg_begin(); SmallVector<Value*, 8> Indices; Indices.append(GEP->op_begin()+1, GEP->op_end()); GetElementPtrInst *GEP_new = GetElementPtrInst::Create(cast<Value>(NI), Indices, "", InsertPoint); fargs.at(argNum)->replaceAllUsesWith(GEP_new); unsigned j = argNum + 1; for(; j < CI->getNumOperands();j++) { if(CI->getOperand(j) == GEP) fargs.at(j)->replaceAllUsesWith(GEP_new); } SmallVector<AttributeWithIndex, 8> AttributesVec; // Get the initial attributes of the call AttrListPtr CallPAL = CI->getAttributes(); Attributes RAttrs = CallPAL.getRetAttributes(); Attributes FnAttrs = CallPAL.getFnAttributes(); if (RAttrs) AttributesVec.push_back(AttributeWithIndex::get(0, RAttrs)); SmallVector<Value*, 8> Args; Args.push_back(GEP->getPointerOperand()); for(unsigned j =1;j<CI->getNumOperands();j++) { Args.push_back(CI->getOperand(j)); // position in the AttributesVec if (Attributes Attrs = CallPAL.getParamAttributes(j)) AttributesVec.push_back(AttributeWithIndex::get(Args.size(), Attrs)); } // Create the new attributes vec. if (FnAttrs != Attribute::None) AttributesVec.push_back(AttributeWithIndex::get(~0, FnAttrs)); AttrListPtr NewCallPAL = AttrListPtr::get(AttributesVec.begin(), AttributesVec.end()); CallInst *CallI = CallInst::Create(NewF,Args,"", CI); CallI->setCallingConv(CI->getCallingConv()); CallI->setAttributes(NewCallPAL); CI->replaceAllUsesWith(CallI); CI->eraseFromParent(); changed = true; } } } } while(changed); return true; }
/// LowerArguments - V8 uses a very simple ABI, where all values are passed in /// either one or two GPRs, including FP values. TODO: we should pass FP values /// in FP registers for fastcc functions. void SparcTargetLowering::LowerArguments(Function &F, SelectionDAG &DAG, SmallVectorImpl<SDValue> &ArgValues, DebugLoc dl) { MachineFunction &MF = DAG.getMachineFunction(); MachineRegisterInfo &RegInfo = MF.getRegInfo(); static const unsigned ArgRegs[] = { SP::I0, SP::I1, SP::I2, SP::I3, SP::I4, SP::I5 }; const unsigned *CurArgReg = ArgRegs, *ArgRegEnd = ArgRegs+6; unsigned ArgOffset = 68; SDValue Root = DAG.getRoot(); std::vector<SDValue> OutChains; for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I) { MVT ObjectVT = getValueType(I->getType()); switch (ObjectVT.getSimpleVT()) { default: assert(0 && "Unhandled argument type!"); case MVT::i1: case MVT::i8: case MVT::i16: case MVT::i32: if (I->use_empty()) { // Argument is dead. if (CurArgReg < ArgRegEnd) ++CurArgReg; ArgValues.push_back(DAG.getUNDEF(ObjectVT)); } else if (CurArgReg < ArgRegEnd) { // Lives in an incoming GPR unsigned VReg = RegInfo.createVirtualRegister(&SP::IntRegsRegClass); MF.getRegInfo().addLiveIn(*CurArgReg++, VReg); SDValue Arg = DAG.getCopyFromReg(Root, dl, VReg, MVT::i32); if (ObjectVT != MVT::i32) { unsigned AssertOp = ISD::AssertSext; Arg = DAG.getNode(AssertOp, dl, MVT::i32, Arg, DAG.getValueType(ObjectVT)); Arg = DAG.getNode(ISD::TRUNCATE, dl, ObjectVT, Arg); } ArgValues.push_back(Arg); } else { int FrameIdx = MF.getFrameInfo()->CreateFixedObject(4, ArgOffset); SDValue FIPtr = DAG.getFrameIndex(FrameIdx, MVT::i32); SDValue Load; if (ObjectVT == MVT::i32) { Load = DAG.getLoad(MVT::i32, dl, Root, FIPtr, NULL, 0); } else { ISD::LoadExtType LoadOp = ISD::SEXTLOAD; // Sparc is big endian, so add an offset based on the ObjectVT. unsigned Offset = 4-std::max(1U, ObjectVT.getSizeInBits()/8); FIPtr = DAG.getNode(ISD::ADD, dl, MVT::i32, FIPtr, DAG.getConstant(Offset, MVT::i32)); Load = DAG.getExtLoad(LoadOp, dl, MVT::i32, Root, FIPtr, NULL, 0, ObjectVT); Load = DAG.getNode(ISD::TRUNCATE, dl, ObjectVT, Load); } ArgValues.push_back(Load); } ArgOffset += 4; break; case MVT::f32: if (I->use_empty()) { // Argument is dead. if (CurArgReg < ArgRegEnd) ++CurArgReg; ArgValues.push_back(DAG.getUNDEF(ObjectVT)); } else if (CurArgReg < ArgRegEnd) { // Lives in an incoming GPR // FP value is passed in an integer register. unsigned VReg = RegInfo.createVirtualRegister(&SP::IntRegsRegClass); MF.getRegInfo().addLiveIn(*CurArgReg++, VReg); SDValue Arg = DAG.getCopyFromReg(Root, dl, VReg, MVT::i32); Arg = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::f32, Arg); ArgValues.push_back(Arg); } else { int FrameIdx = MF.getFrameInfo()->CreateFixedObject(4, ArgOffset); SDValue FIPtr = DAG.getFrameIndex(FrameIdx, MVT::i32); SDValue Load = DAG.getLoad(MVT::f32, dl, Root, FIPtr, NULL, 0); ArgValues.push_back(Load); } ArgOffset += 4; break; case MVT::i64: case MVT::f64: if (I->use_empty()) { // Argument is dead. if (CurArgReg < ArgRegEnd) ++CurArgReg; if (CurArgReg < ArgRegEnd) ++CurArgReg; ArgValues.push_back(DAG.getUNDEF(ObjectVT)); } else { SDValue HiVal; if (CurArgReg < ArgRegEnd) { // Lives in an incoming GPR unsigned VRegHi = RegInfo.createVirtualRegister(&SP::IntRegsRegClass); MF.getRegInfo().addLiveIn(*CurArgReg++, VRegHi); HiVal = DAG.getCopyFromReg(Root, dl, VRegHi, MVT::i32); } else { int FrameIdx = MF.getFrameInfo()->CreateFixedObject(4, ArgOffset); SDValue FIPtr = DAG.getFrameIndex(FrameIdx, MVT::i32); HiVal = DAG.getLoad(MVT::i32, dl, Root, FIPtr, NULL, 0); } SDValue LoVal; if (CurArgReg < ArgRegEnd) { // Lives in an incoming GPR unsigned VRegLo = RegInfo.createVirtualRegister(&SP::IntRegsRegClass); MF.getRegInfo().addLiveIn(*CurArgReg++, VRegLo); LoVal = DAG.getCopyFromReg(Root, dl, VRegLo, MVT::i32); } else { int FrameIdx = MF.getFrameInfo()->CreateFixedObject(4, ArgOffset+4); SDValue FIPtr = DAG.getFrameIndex(FrameIdx, MVT::i32); LoVal = DAG.getLoad(MVT::i32, dl, Root, FIPtr, NULL, 0); } // Compose the two halves together into an i64 unit. SDValue WholeValue = DAG.getNode(ISD::BUILD_PAIR, dl, MVT::i64, LoVal, HiVal); // If we want a double, do a bit convert. if (ObjectVT == MVT::f64) WholeValue = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::f64, WholeValue); ArgValues.push_back(WholeValue); } ArgOffset += 8; break; } } // Store remaining ArgRegs to the stack if this is a varargs function. if (F.isVarArg()) { // Remember the vararg offset for the va_start implementation. VarArgsFrameOffset = ArgOffset; for (; CurArgReg != ArgRegEnd; ++CurArgReg) { unsigned VReg = RegInfo.createVirtualRegister(&SP::IntRegsRegClass); MF.getRegInfo().addLiveIn(*CurArgReg, VReg); SDValue Arg = DAG.getCopyFromReg(DAG.getRoot(), dl, VReg, MVT::i32); int FrameIdx = MF.getFrameInfo()->CreateFixedObject(4, ArgOffset); SDValue FIPtr = DAG.getFrameIndex(FrameIdx, MVT::i32); OutChains.push_back(DAG.getStore(DAG.getRoot(), dl, Arg, FIPtr, NULL, 0)); ArgOffset += 4; } } if (!OutChains.empty()) DAG.setRoot(DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &OutChains[0], OutChains.size())); }
// // Method: runOnModule() // // Description: // Entry point for this LLVM pass. // Clone functions that take LoadInsts as arguments // // Inputs: // M - A reference to the LLVM module to transform // // Outputs: // M - The transformed LLVM module. // // Return value: // true - The module was modified. // false - The module was not modified. // bool LoadArgs::runOnModule(Module& M) { std::map<std::pair<Function*, const Type * > , Function* > fnCache; bool changed; do { changed = false; for (Module::iterator Func = M.begin(); Func != M.end(); ++Func) { for (Function::iterator B = Func->begin(), FE = Func->end(); B != FE; ++B) { for (BasicBlock::iterator I = B->begin(), BE = B->end(); I != BE;) { CallInst *CI = dyn_cast<CallInst>(I++); if(!CI) continue; if(CI->hasByValArgument()) continue; // if the CallInst calls a function, that is externally defined, // or might be changed, ignore this call site. Function *F = CI->getCalledFunction(); if (!F || (F->isDeclaration() || F->mayBeOverridden())) continue; if(F->hasStructRetAttr()) continue; if(F->isVarArg()) continue; // find the argument we must replace Function::arg_iterator ai = F->arg_begin(), ae = F->arg_end(); unsigned argNum = 0; for(; argNum < CI->getNumArgOperands();argNum++, ++ai) { // do not care about dead arguments if(ai->use_empty()) continue; if(F->getAttributes().getParamAttributes(argNum).hasAttrSomewhere(Attribute::SExt) || F->getAttributes().getParamAttributes(argNum).hasAttrSomewhere(Attribute::ZExt)) continue; if (isa<LoadInst>(CI->getArgOperand(argNum))) break; } // if no argument was a GEP operator to be changed if(ai == ae) continue; LoadInst *LI = dyn_cast<LoadInst>(CI->getArgOperand(argNum)); Instruction * InsertPt = &(Func->getEntryBlock().front()); AllocaInst *NewVal = new AllocaInst(LI->getType(), "",InsertPt); StoreInst *Copy = new StoreInst(LI, NewVal); Copy->insertAfter(LI); /*if(LI->getParent() != CI->getParent()) continue; // Also check that there is no store after the load. // TODO: Check if the load/store do not alias. BasicBlock::iterator bii = LI->getParent()->begin(); Instruction *BII = bii; while(BII != LI) { ++bii; BII = bii; } while(BII != CI) { if(isa<StoreInst>(BII)) break; ++bii; BII = bii; } if(isa<StoreInst>(bii)){ continue; }*/ // Construct the new Type // Appends the struct Type at the beginning std::vector<Type*>TP; for(unsigned c = 0; c < CI->getNumArgOperands();c++) { if(c == argNum) TP.push_back(LI->getPointerOperand()->getType()); TP.push_back(CI->getArgOperand(c)->getType()); } //return type is same as that of original instruction FunctionType *NewFTy = FunctionType::get(CI->getType(), TP, false); numSimplified++; //if(numSimplified > 1000) //return true; Function *NewF; std::map<std::pair<Function*, const Type* > , Function* >::iterator Test; Test = fnCache.find(std::make_pair(F, NewFTy)); if(Test != fnCache.end()) { NewF = Test->second; } else { NewF = Function::Create(NewFTy, GlobalValue::InternalLinkage, F->getName().str() + ".TEST", &M); fnCache[std::make_pair(F, NewFTy)] = NewF; Function::arg_iterator NI = NewF->arg_begin(); ValueToValueMapTy ValueMap; unsigned count = 0; for (Function::arg_iterator II = F->arg_begin(); NI != NewF->arg_end(); ++count, ++NI) { if(count == argNum) { NI->setName("LDarg"); continue; } ValueMap[II] = NI; NI->setName(II->getName()); NI->addAttr(F->getAttributes().getParamAttributes(II->getArgNo() + 1)); ++II; } // Perform the cloning. SmallVector<ReturnInst*,100> Returns; CloneFunctionInto(NewF, F, ValueMap, false, Returns); std::vector<Value*> fargs; for(Function::arg_iterator ai = NewF->arg_begin(), ae= NewF->arg_end(); ai != ae; ++ai) { fargs.push_back(ai); } NewF->setAttributes(NewF->getAttributes().addAttributes( F->getContext(), 0, F->getAttributes().getRetAttributes())); NewF->setAttributes(NewF->getAttributes().addAttributes( F->getContext(), ~0, F->getAttributes().getFnAttributes())); //Get the point to insert the GEP instr. Instruction *InsertPoint; for (BasicBlock::iterator insrt = NewF->front().begin(); isa<AllocaInst>(InsertPoint = insrt); ++insrt) {;} LoadInst *LI_new = new LoadInst(fargs.at(argNum), "", InsertPoint); fargs.at(argNum+1)->replaceAllUsesWith(LI_new); } //this does not seem to be a good idea AttributeSet NewCallPAL=AttributeSet(); // Get the initial attributes of the call AttributeSet CallPAL = CI->getAttributes(); AttributeSet RAttrs = CallPAL.getRetAttributes(); AttributeSet FnAttrs = CallPAL.getFnAttributes(); if (!RAttrs.isEmpty()) NewCallPAL=NewCallPAL.addAttributes(F->getContext(),0, RAttrs); SmallVector<Value*, 8> Args; for(unsigned j =0;j<CI->getNumArgOperands();j++) { if(j == argNum) { Args.push_back(NewVal); } Args.push_back(CI->getArgOperand(j)); // position in the NewCallPAL AttributeSet Attrs = CallPAL.getParamAttributes(j+1); if (!Attrs.isEmpty()) NewCallPAL=NewCallPAL.addAttributes(F->getContext(),Args.size(), Attrs); } // Create the new attributes vec. if (!FnAttrs.isEmpty()) NewCallPAL=NewCallPAL.addAttributes(F->getContext(),~0, FnAttrs); CallInst *CallI = CallInst::Create(NewF,Args,"", CI); CallI->setCallingConv(CI->getCallingConv()); CallI->setAttributes(NewCallPAL); CI->replaceAllUsesWith(CallI); CI->eraseFromParent(); changed = true; } } } } while(changed); return true; }
/// DoPromotion - This method actually performs the promotion of the specified /// arguments, and returns the new function. At this point, we know that it's /// safe to do so. static Function * doPromotion(Function *F, SmallPtrSetImpl<Argument *> &ArgsToPromote, SmallPtrSetImpl<Argument *> &ByValArgsToTransform, Optional<function_ref<void(CallSite OldCS, CallSite NewCS)>> ReplaceCallSite) { // Start by computing a new prototype for the function, which is the same as // the old function, but has modified arguments. FunctionType *FTy = F->getFunctionType(); std::vector<Type *> Params; using ScalarizeTable = std::set<std::pair<Type *, IndicesVector>>; // ScalarizedElements - If we are promoting a pointer that has elements // accessed out of it, keep track of which elements are accessed so that we // can add one argument for each. // // Arguments that are directly loaded will have a zero element value here, to // handle cases where there are both a direct load and GEP accesses. std::map<Argument *, ScalarizeTable> ScalarizedElements; // OriginalLoads - Keep track of a representative load instruction from the // original function so that we can tell the alias analysis implementation // what the new GEP/Load instructions we are inserting look like. // We need to keep the original loads for each argument and the elements // of the argument that are accessed. std::map<std::pair<Argument *, IndicesVector>, LoadInst *> OriginalLoads; // Attribute - Keep track of the parameter attributes for the arguments // that we are *not* promoting. For the ones that we do promote, the parameter // attributes are lost SmallVector<AttributeSet, 8> ArgAttrVec; AttributeList PAL = F->getAttributes(); // First, determine the new argument list unsigned ArgNo = 0; for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I, ++ArgNo) { if (ByValArgsToTransform.count(&*I)) { // Simple byval argument? Just add all the struct element types. Type *AgTy = cast<PointerType>(I->getType())->getElementType(); StructType *STy = cast<StructType>(AgTy); Params.insert(Params.end(), STy->element_begin(), STy->element_end()); ArgAttrVec.insert(ArgAttrVec.end(), STy->getNumElements(), AttributeSet()); ++NumByValArgsPromoted; } else if (!ArgsToPromote.count(&*I)) { // Unchanged argument Params.push_back(I->getType()); ArgAttrVec.push_back(PAL.getParamAttributes(ArgNo)); } else if (I->use_empty()) { // Dead argument (which are always marked as promotable) ++NumArgumentsDead; // There may be remaining metadata uses of the argument for things like // llvm.dbg.value. Replace them with undef. I->replaceAllUsesWith(UndefValue::get(I->getType())); } else { // Okay, this is being promoted. This means that the only uses are loads // or GEPs which are only used by loads // In this table, we will track which indices are loaded from the argument // (where direct loads are tracked as no indices). ScalarizeTable &ArgIndices = ScalarizedElements[&*I]; for (User *U : I->users()) { Instruction *UI = cast<Instruction>(U); Type *SrcTy; if (LoadInst *L = dyn_cast<LoadInst>(UI)) SrcTy = L->getType(); else SrcTy = cast<GetElementPtrInst>(UI)->getSourceElementType(); IndicesVector Indices; Indices.reserve(UI->getNumOperands() - 1); // Since loads will only have a single operand, and GEPs only a single // non-index operand, this will record direct loads without any indices, // and gep+loads with the GEP indices. for (User::op_iterator II = UI->op_begin() + 1, IE = UI->op_end(); II != IE; ++II) Indices.push_back(cast<ConstantInt>(*II)->getSExtValue()); // GEPs with a single 0 index can be merged with direct loads if (Indices.size() == 1 && Indices.front() == 0) Indices.clear(); ArgIndices.insert(std::make_pair(SrcTy, Indices)); LoadInst *OrigLoad; if (LoadInst *L = dyn_cast<LoadInst>(UI)) OrigLoad = L; else // Take any load, we will use it only to update Alias Analysis OrigLoad = cast<LoadInst>(UI->user_back()); OriginalLoads[std::make_pair(&*I, Indices)] = OrigLoad; } // Add a parameter to the function for each element passed in. for (const auto &ArgIndex : ArgIndices) { // not allowed to dereference ->begin() if size() is 0 Params.push_back(GetElementPtrInst::getIndexedType( cast<PointerType>(I->getType()->getScalarType())->getElementType(), ArgIndex.second)); ArgAttrVec.push_back(AttributeSet()); assert(Params.back()); } if (ArgIndices.size() == 1 && ArgIndices.begin()->second.empty()) ++NumArgumentsPromoted; else ++NumAggregatesPromoted; } } Type *RetTy = FTy->getReturnType(); // Construct the new function type using the new arguments. FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg()); // Create the new function body and insert it into the module. Function *NF = Function::Create(NFTy, F->getLinkage(), F->getName()); NF->copyAttributesFrom(F); // Patch the pointer to LLVM function in debug info descriptor. NF->setSubprogram(F->getSubprogram()); F->setSubprogram(nullptr); DEBUG(dbgs() << "ARG PROMOTION: Promoting to:" << *NF << "\n" << "From: " << *F); // Recompute the parameter attributes list based on the new arguments for // the function. NF->setAttributes(AttributeList::get(F->getContext(), PAL.getFnAttributes(), PAL.getRetAttributes(), ArgAttrVec)); ArgAttrVec.clear(); F->getParent()->getFunctionList().insert(F->getIterator(), NF); NF->takeName(F); // Loop over all of the callers of the function, transforming the call sites // to pass in the loaded pointers. // SmallVector<Value *, 16> Args; while (!F->use_empty()) { CallSite CS(F->user_back()); assert(CS.getCalledFunction() == F); Instruction *Call = CS.getInstruction(); const AttributeList &CallPAL = CS.getAttributes(); // Loop over the operands, inserting GEP and loads in the caller as // appropriate. CallSite::arg_iterator AI = CS.arg_begin(); ArgNo = 0; for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I, ++AI, ++ArgNo) if (!ArgsToPromote.count(&*I) && !ByValArgsToTransform.count(&*I)) { Args.push_back(*AI); // Unmodified argument ArgAttrVec.push_back(CallPAL.getParamAttributes(ArgNo)); } else if (ByValArgsToTransform.count(&*I)) { // Emit a GEP and load for each element of the struct. Type *AgTy = cast<PointerType>(I->getType())->getElementType(); StructType *STy = cast<StructType>(AgTy); Value *Idxs[2] = { ConstantInt::get(Type::getInt32Ty(F->getContext()), 0), nullptr}; for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { Idxs[1] = ConstantInt::get(Type::getInt32Ty(F->getContext()), i); Value *Idx = GetElementPtrInst::Create( STy, *AI, Idxs, (*AI)->getName() + "." + Twine(i), Call); // TODO: Tell AA about the new values? Args.push_back(new LoadInst(Idx, Idx->getName() + ".val", Call)); ArgAttrVec.push_back(AttributeSet()); } } else if (!I->use_empty()) { // Non-dead argument: insert GEPs and loads as appropriate. ScalarizeTable &ArgIndices = ScalarizedElements[&*I]; // Store the Value* version of the indices in here, but declare it now // for reuse. std::vector<Value *> Ops; for (const auto &ArgIndex : ArgIndices) { Value *V = *AI; LoadInst *OrigLoad = OriginalLoads[std::make_pair(&*I, ArgIndex.second)]; if (!ArgIndex.second.empty()) { Ops.reserve(ArgIndex.second.size()); Type *ElTy = V->getType(); for (auto II : ArgIndex.second) { // Use i32 to index structs, and i64 for others (pointers/arrays). // This satisfies GEP constraints. Type *IdxTy = (ElTy->isStructTy() ? Type::getInt32Ty(F->getContext()) : Type::getInt64Ty(F->getContext())); Ops.push_back(ConstantInt::get(IdxTy, II)); // Keep track of the type we're currently indexing. if (auto *ElPTy = dyn_cast<PointerType>(ElTy)) ElTy = ElPTy->getElementType(); else ElTy = cast<CompositeType>(ElTy)->getTypeAtIndex(II); } // And create a GEP to extract those indices. V = GetElementPtrInst::Create(ArgIndex.first, V, Ops, V->getName() + ".idx", Call); Ops.clear(); } // Since we're replacing a load make sure we take the alignment // of the previous load. LoadInst *newLoad = new LoadInst(V, V->getName() + ".val", Call); newLoad->setAlignment(OrigLoad->getAlignment()); // Transfer the AA info too. AAMDNodes AAInfo; OrigLoad->getAAMetadata(AAInfo); newLoad->setAAMetadata(AAInfo); Args.push_back(newLoad); ArgAttrVec.push_back(AttributeSet()); } } // Push any varargs arguments on the list. for (; AI != CS.arg_end(); ++AI, ++ArgNo) { Args.push_back(*AI); ArgAttrVec.push_back(CallPAL.getParamAttributes(ArgNo)); } SmallVector<OperandBundleDef, 1> OpBundles; CS.getOperandBundlesAsDefs(OpBundles); CallSite NewCS; if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) { NewCS = InvokeInst::Create(NF, II->getNormalDest(), II->getUnwindDest(), Args, OpBundles, "", Call); } else { auto *NewCall = CallInst::Create(NF, Args, OpBundles, "", Call); NewCall->setTailCallKind(cast<CallInst>(Call)->getTailCallKind()); NewCS = NewCall; } NewCS.setCallingConv(CS.getCallingConv()); NewCS.setAttributes( AttributeList::get(F->getContext(), CallPAL.getFnAttributes(), CallPAL.getRetAttributes(), ArgAttrVec)); NewCS->setDebugLoc(Call->getDebugLoc()); uint64_t W; if (Call->extractProfTotalWeight(W)) NewCS->setProfWeight(W); Args.clear(); ArgAttrVec.clear(); // Update the callgraph to know that the callsite has been transformed. if (ReplaceCallSite) (*ReplaceCallSite)(CS, NewCS); if (!Call->use_empty()) { Call->replaceAllUsesWith(NewCS.getInstruction()); NewCS->takeName(Call); } // Finally, remove the old call from the program, reducing the use-count of // F. Call->eraseFromParent(); } const DataLayout &DL = F->getParent()->getDataLayout(); // Since we have now created the new function, splice the body of the old // function right into the new function, leaving the old rotting hulk of the // function empty. NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList()); // Loop over the argument list, transferring uses of the old arguments over to // the new arguments, also transferring over the names as well. for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(), I2 = NF->arg_begin(); I != E; ++I) { if (!ArgsToPromote.count(&*I) && !ByValArgsToTransform.count(&*I)) { // If this is an unmodified argument, move the name and users over to the // new version. I->replaceAllUsesWith(&*I2); I2->takeName(&*I); ++I2; continue; } if (ByValArgsToTransform.count(&*I)) { // In the callee, we create an alloca, and store each of the new incoming // arguments into the alloca. Instruction *InsertPt = &NF->begin()->front(); // Just add all the struct element types. Type *AgTy = cast<PointerType>(I->getType())->getElementType(); Value *TheAlloca = new AllocaInst(AgTy, DL.getAllocaAddrSpace(), nullptr, I->getParamAlignment(), "", InsertPt); StructType *STy = cast<StructType>(AgTy); Value *Idxs[2] = {ConstantInt::get(Type::getInt32Ty(F->getContext()), 0), nullptr}; for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { Idxs[1] = ConstantInt::get(Type::getInt32Ty(F->getContext()), i); Value *Idx = GetElementPtrInst::Create( AgTy, TheAlloca, Idxs, TheAlloca->getName() + "." + Twine(i), InsertPt); I2->setName(I->getName() + "." + Twine(i)); new StoreInst(&*I2++, Idx, InsertPt); } // Anything that used the arg should now use the alloca. I->replaceAllUsesWith(TheAlloca); TheAlloca->takeName(&*I); // If the alloca is used in a call, we must clear the tail flag since // the callee now uses an alloca from the caller. for (User *U : TheAlloca->users()) { CallInst *Call = dyn_cast<CallInst>(U); if (!Call) continue; Call->setTailCall(false); } continue; } if (I->use_empty()) continue; // Otherwise, if we promoted this argument, then all users are load // instructions (or GEPs with only load users), and all loads should be // using the new argument that we added. ScalarizeTable &ArgIndices = ScalarizedElements[&*I]; while (!I->use_empty()) { if (LoadInst *LI = dyn_cast<LoadInst>(I->user_back())) { assert(ArgIndices.begin()->second.empty() && "Load element should sort to front!"); I2->setName(I->getName() + ".val"); LI->replaceAllUsesWith(&*I2); LI->eraseFromParent(); DEBUG(dbgs() << "*** Promoted load of argument '" << I->getName() << "' in function '" << F->getName() << "'\n"); } else { GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->user_back()); IndicesVector Operands; Operands.reserve(GEP->getNumIndices()); for (User::op_iterator II = GEP->idx_begin(), IE = GEP->idx_end(); II != IE; ++II) Operands.push_back(cast<ConstantInt>(*II)->getSExtValue()); // GEPs with a single 0 index can be merged with direct loads if (Operands.size() == 1 && Operands.front() == 0) Operands.clear(); Function::arg_iterator TheArg = I2; for (ScalarizeTable::iterator It = ArgIndices.begin(); It->second != Operands; ++It, ++TheArg) { assert(It != ArgIndices.end() && "GEP not handled??"); } std::string NewName = I->getName(); for (unsigned i = 0, e = Operands.size(); i != e; ++i) { NewName += "." + utostr(Operands[i]); } NewName += ".val"; TheArg->setName(NewName); DEBUG(dbgs() << "*** Promoted agg argument '" << TheArg->getName() << "' of function '" << NF->getName() << "'\n"); // All of the uses must be load instructions. Replace them all with // the argument specified by ArgNo. while (!GEP->use_empty()) { LoadInst *L = cast<LoadInst>(GEP->user_back()); L->replaceAllUsesWith(&*TheArg); L->eraseFromParent(); } GEP->eraseFromParent(); } } // Increment I2 past all of the arguments added for this promoted pointer. std::advance(I2, ArgIndices.size()); } return NF; }