X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FIPO%2FArgumentPromotion.cpp;h=fe30381170dc5006fbf2080a98ef2b9f360c2bc5;hb=4d70a2949007edeaad4662d5cdcb2d272cb2b2ff;hp=f3e0b18573c6a9c47832e66007408606e51cf37d;hpb=a7235ea7245028a0723e8ab7fd011386b3900777;p=oota-llvm.git diff --git a/lib/Transforms/IPO/ArgumentPromotion.cpp b/lib/Transforms/IPO/ArgumentPromotion.cpp index f3e0b18573c..fe30381170d 100644 --- a/lib/Transforms/IPO/ArgumentPromotion.cpp +++ b/lib/Transforms/IPO/ArgumentPromotion.cpp @@ -39,14 +39,13 @@ #include "llvm/LLVMContext.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Analysis/CallGraph.h" -#include "llvm/Target/TargetData.h" #include "llvm/Support/CallSite.h" -#include "llvm/Support/Compiler.h" #include "llvm/Support/CFG.h" #include "llvm/Support/Debug.h" #include "llvm/Support/raw_ostream.h" #include "llvm/ADT/DepthFirstIterator.h" #include "llvm/ADT/Statistic.h" +#include "llvm/ADT/StringExtras.h" #include using namespace llvm; @@ -58,51 +57,60 @@ STATISTIC(NumArgumentsDead , "Number of dead pointer args eliminated"); namespace { /// ArgPromotion - The 'by reference' to 'by value' argument promotion pass. /// - struct VISIBILITY_HIDDEN ArgPromotion : public CallGraphSCCPass { + struct ArgPromotion : public CallGraphSCCPass { virtual void getAnalysisUsage(AnalysisUsage &AU) const { AU.addRequired(); - AU.addRequired(); CallGraphSCCPass::getAnalysisUsage(AU); } - virtual bool runOnSCC(const std::vector &SCC); + virtual bool runOnSCC(CallGraphSCC &SCC); static char ID; // Pass identification, replacement for typeid explicit ArgPromotion(unsigned maxElements = 3) - : CallGraphSCCPass(&ID), maxElements(maxElements) {} + : CallGraphSCCPass(ID), maxElements(maxElements) { + initializeArgPromotionPass(*PassRegistry::getPassRegistry()); + } /// A vector used to hold the indices of a single GEP instruction typedef std::vector IndicesVector; private: - bool PromoteArguments(CallGraphNode *CGN); + CallGraphNode *PromoteArguments(CallGraphNode *CGN); bool isSafeToPromoteArgument(Argument *Arg, bool isByVal) const; - Function *DoPromotion(Function *F, - SmallPtrSet &ArgsToPromote, - SmallPtrSet &ByValArgsToTransform); + CallGraphNode *DoPromotion(Function *F, + SmallPtrSet &ArgsToPromote, + SmallPtrSet &ByValArgsToTransform); /// The maximum number of elements to expand, or 0 for unlimited. unsigned maxElements; }; } char ArgPromotion::ID = 0; -static RegisterPass -X("argpromotion", "Promote 'by reference' arguments to scalars"); +INITIALIZE_PASS_BEGIN(ArgPromotion, "argpromotion", + "Promote 'by reference' arguments to scalars", false, false) +INITIALIZE_AG_DEPENDENCY(AliasAnalysis) +INITIALIZE_AG_DEPENDENCY(CallGraph) +INITIALIZE_PASS_END(ArgPromotion, "argpromotion", + "Promote 'by reference' arguments to scalars", false, false) Pass *llvm::createArgumentPromotionPass(unsigned maxElements) { return new ArgPromotion(maxElements); } -bool ArgPromotion::runOnSCC(const std::vector &SCC) { +bool ArgPromotion::runOnSCC(CallGraphSCC &SCC) { bool Changed = false, LocalChange; do { // Iterate until we stop promoting from this SCC. LocalChange = false; // Attempt to promote arguments from all functions in this SCC. - for (unsigned i = 0, e = SCC.size(); i != e; ++i) - LocalChange |= PromoteArguments(SCC[i]); + for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) { + if (CallGraphNode *CGN = PromoteArguments(*I)) { + LocalChange = true; + SCC.ReplaceNode(*I, CGN); + } + } Changed |= LocalChange; // Remember that we changed something. } while (LocalChange); - + return Changed; } @@ -111,25 +119,25 @@ bool ArgPromotion::runOnSCC(const std::vector &SCC) { /// example, all callers are direct). If safe to promote some arguments, it /// calls the DoPromotion method. /// -bool ArgPromotion::PromoteArguments(CallGraphNode *CGN) { +CallGraphNode *ArgPromotion::PromoteArguments(CallGraphNode *CGN) { Function *F = CGN->getFunction(); // Make sure that it is local to this module. - if (!F || !F->hasLocalLinkage()) return false; + if (!F || !F->hasLocalLinkage()) return 0; // First check: see if there are any pointer arguments! If not, quick exit. SmallVector, 16> PointerArgs; unsigned ArgNo = 0; for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I, ++ArgNo) - if (isa(I->getType())) + if (I->getType()->isPointerTy()) PointerArgs.push_back(std::pair(I, ArgNo)); - if (PointerArgs.empty()) return false; + if (PointerArgs.empty()) return 0; // Second check: make sure that all callers are direct callers. We can't // transform functions that have indirect callers. if (F->hasAddressTaken()) - return false; + return 0; // Check to see which arguments are promotable. If an argument is promotable, // add it to ArgsToPromote. @@ -145,7 +153,7 @@ bool ArgPromotion::PromoteArguments(CallGraphNode *CGN) { const Type *AgTy = cast(PtrArg->getType())->getElementType(); if (const StructType *STy = dyn_cast(AgTy)) { if (maxElements > 0 && STy->getNumElements() > maxElements) { - DEBUG(errs() << "argpromotion disable promoting argument '" + DEBUG(dbgs() << "argpromotion disable promoting argument '" << PtrArg->getName() << "' because it would require adding more" << " than " << maxElements << " arguments to the function.\n"); } else { @@ -174,26 +182,10 @@ bool ArgPromotion::PromoteArguments(CallGraphNode *CGN) { } // No promotable pointer arguments. - if (ArgsToPromote.empty() && ByValArgsToTransform.empty()) return false; + if (ArgsToPromote.empty() && ByValArgsToTransform.empty()) + return 0; - Function *NewF = DoPromotion(F, ArgsToPromote, ByValArgsToTransform); - - // Update the call graph to know that the function has been transformed. - getAnalysis().changeFunction(F, NewF); - return true; -} - -/// IsAlwaysValidPointer - Return true if the specified pointer is always legal -/// to load. -static bool IsAlwaysValidPointer(Value *V) { - if (isa(V) || isa(V)) return true; - if (GetElementPtrInst *GEP = dyn_cast(V)) - return IsAlwaysValidPointer(GEP->getOperand(0)); - if (ConstantExpr *CE = dyn_cast(V)) - if (CE->getOpcode() == Instruction::GetElementPtr) - return IsAlwaysValidPointer(CE->getOperand(0)); - - return false; + return DoPromotion(F, ArgsToPromote, ByValArgsToTransform); } /// AllCalleesPassInValidPointerForArgument - Return true if we can prove that @@ -208,10 +200,10 @@ static bool AllCalleesPassInValidPointerForArgument(Argument *Arg) { // have direct callees. for (Value::use_iterator UI = Callee->use_begin(), E = Callee->use_end(); UI != E; ++UI) { - CallSite CS = CallSite::get(*UI); - assert(CS.getInstruction() && "Should only have direct calls!"); + CallSite CS(*UI); + assert(CS && "Should only have direct calls!"); - if (!IsAlwaysValidPointer(CS.getArgument(ArgNo))) + if (!CS.getArgument(ArgNo)->isDereferenceablePointer()) return false; } return true; @@ -248,7 +240,7 @@ static bool PrefixIn(const ArgPromotion::IndicesVector &Indices, return Low != Set.end() && IsPrefix(*Low, Indices); } -/// Mark the given indices (ToMark) as safe in the the given set of indices +/// Mark the given indices (ToMark) as safe in the given set of indices /// (Safe). Marking safe usually means adding ToMark to Safe. However, if there /// is already a prefix of Indices in Safe, Indices are implicitely marked safe /// already. Furthermore, any indices that Indices is itself a prefix of, are @@ -318,7 +310,7 @@ bool ArgPromotion::isSafeToPromoteArgument(Argument *Arg, bool isByVal) const { GEPIndicesSet ToPromote; // If the pointer is always valid, any load with first index 0 is valid. - if(isByVal || AllCalleesPassInValidPointerForArgument(Arg)) + if (isByVal || AllCalleesPassInValidPointerForArgument(Arg)) SafeToUnconditionallyLoad.insert(IndicesVector(1, 0)); // First, iterate the entry block and mark loads of (geps of) arguments as @@ -360,19 +352,20 @@ bool ArgPromotion::isSafeToPromoteArgument(Argument *Arg, bool isByVal) const { IndicesVector Operands; for (Value::use_iterator UI = Arg->use_begin(), E = Arg->use_end(); UI != E; ++UI) { + User *U = *UI; Operands.clear(); - if (LoadInst *LI = dyn_cast(*UI)) { + if (LoadInst *LI = dyn_cast(U)) { if (LI->isVolatile()) return false; // Don't hack volatile loads Loads.push_back(LI); // Direct loads are equivalent to a GEP with a zero index and then a load. Operands.push_back(0); - } else if (GetElementPtrInst *GEP = dyn_cast(*UI)) { + } else if (GetElementPtrInst *GEP = dyn_cast(U)) { if (GEP->use_empty()) { // Dead GEP's cause trouble later. Just remove them if we run into // them. getAnalysis().deleteValue(GEP); GEP->eraseFromParent(); - // TODO: This runs the above loop over and over again for dead GEPS + // TODO: This runs the above loop over and over again for dead GEPs // Couldn't we just do increment the UI iterator earlier and erase the // use? return isSafeToPromoteArgument(Arg, isByVal); @@ -410,7 +403,7 @@ bool ArgPromotion::isSafeToPromoteArgument(Argument *Arg, bool isByVal) const { // to do. if (ToPromote.find(Operands) == ToPromote.end()) { if (maxElements > 0 && ToPromote.size() == maxElements) { - DEBUG(errs() << "argpromotion not promoting argument '" + DEBUG(dbgs() << "argpromotion not promoting argument '" << Arg->getName() << "' because it would require adding more " << "than " << maxElements << " arguments to the function.\n"); // We limit aggregate promotion to only promoting up to a fixed number @@ -433,7 +426,6 @@ bool ArgPromotion::isSafeToPromoteArgument(Argument *Arg, bool isByVal) const { SmallPtrSet TranspBlocks; AliasAnalysis &AA = getAnalysis(); - TargetData &TD = getAnalysis(); for (unsigned i = 0, e = Loads.size(); i != e; ++i) { // Check to see if the load is invalidated from the start of the block to @@ -441,22 +433,24 @@ bool ArgPromotion::isSafeToPromoteArgument(Argument *Arg, bool isByVal) const { LoadInst *Load = Loads[i]; BasicBlock *BB = Load->getParent(); - const PointerType *LoadTy = - cast(Load->getPointerOperand()->getType()); - unsigned LoadSize = (unsigned)TD.getTypeStoreSize(LoadTy->getElementType()); + AliasAnalysis::Location Loc(Load->getPointerOperand(), + AA.getTypeStoreSize(Load->getType()), + Load->getMetadata(LLVMContext::MD_tbaa)); - if (AA.canInstructionRangeModify(BB->front(), *Load, Arg, LoadSize)) + if (AA.canInstructionRangeModify(BB->front(), *Load, Loc)) return false; // Pointer is invalidated! // Now check every path from the entry block to the load for transparency. // To do this, we perform a depth first search on the inverse CFG from the // loading block. - for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) + for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) { + BasicBlock *P = *PI; for (idf_ext_iterator > - I = idf_ext_begin(*PI, TranspBlocks), - E = idf_ext_end(*PI, TranspBlocks); I != E; ++I) - if (AA.canBasicBlockModify(**I, Arg, LoadSize)) + I = idf_ext_begin(P, TranspBlocks), + E = idf_ext_end(P, TranspBlocks); I != E; ++I) + if (AA.canBasicBlockModify(**I, Loc)) return false; + } } // If the path from the entry of the function to each load is free of @@ -468,8 +462,8 @@ bool ArgPromotion::isSafeToPromoteArgument(Argument *Arg, bool isByVal) const { /// 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. -Function *ArgPromotion::DoPromotion(Function *F, - SmallPtrSet &ArgsToPromote, +CallGraphNode *ArgPromotion::DoPromotion(Function *F, + SmallPtrSet &ArgsToPromote, SmallPtrSet &ByValArgsToTransform) { // Start by computing a new prototype for the function, which is the same as @@ -582,19 +576,24 @@ Function *ArgPromotion::DoPromotion(Function *F, bool ExtraArgHack = false; if (Params.empty() && FTy->isVarArg()) { ExtraArgHack = true; - Params.push_back(Type::Int32Ty); + 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... + // 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())); + NF->setAttributes(AttrListPtr::get(AttributesVec.begin(), + AttributesVec.end())); AttributesVec.clear(); F->getParent()->getFunctionList().insert(F, NF); @@ -607,13 +606,17 @@ Function *ArgPromotion::DoPromotion(Function *F, // Get the callgraph information that we need to update to reflect our // changes. CallGraph &CG = getAnalysis(); + + // 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 Args; while (!F->use_empty()) { - CallSite CS = CallSite::get(F->use_back()); + CallSite CS(F->use_back()); + assert(CS.getCalledFunction() == F); Instruction *Call = CS.getInstruction(); const AttrListPtr &CallPAL = CS.getAttributes(); @@ -637,9 +640,10 @@ Function *ArgPromotion::DoPromotion(Function *F, // Emit a GEP and load for each element of the struct. const Type *AgTy = cast(I->getType())->getElementType(); const StructType *STy = cast(AgTy); - Value *Idxs[2] = { ConstantInt::get(Type::Int32Ty, 0), 0 }; + 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::Int32Ty, i); + Idxs[1] = ConstantInt::get(Type::getInt32Ty(F->getContext()), i); Value *Idx = GetElementPtrInst::Create(*AI, Idxs, Idxs+2, (*AI)->getName()+"."+utostr(i), Call); @@ -650,7 +654,7 @@ Function *ArgPromotion::DoPromotion(Function *F, // 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 + // for reuse. std::vector Ops; for (ScalarizeTable::iterator SI = ArgIndices.begin(), E = ArgIndices.end(); SI != E; ++SI) { @@ -663,26 +667,35 @@ Function *ArgPromotion::DoPromotion(Function *F, IE = SI->end(); II != IE; ++II) { // Use i32 to index structs, and i64 for others (pointers/arrays). // This satisfies GEP constraints. - const Type *IdxTy = (isa(ElTy) ? Type::Int32Ty : Type::Int64Ty); + 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 + // Keep track of the type we're currently indexing. ElTy = cast(ElTy)->getTypeAtIndex(*II); } - // And create a GEP to extract those indices + // 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); } - Args.push_back(new LoadInst(V, V->getName()+".val", Call)); + // 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 TBAA info too. + newLoad->setMetadata(LLVMContext::MD_tbaa, + OrigLoad->getMetadata(LLVMContext::MD_tbaa)); + Args.push_back(newLoad); AA.copyValue(OrigLoad, Args.back()); } } if (ExtraArgHack) - Args.push_back(Constant::getNullValue(Type::Int32Ty)); + Args.push_back(Constant::getNullValue(Type::getInt32Ty(F->getContext()))); - // Push any varargs arguments on the list + // Push any varargs arguments on the list. for (; AI != CS.arg_end(); ++AI, ++ArgIndex) { Args.push_back(*AI); if (Attributes Attrs = CallPAL.getParamAttributes(ArgIndex)) @@ -716,7 +729,8 @@ Function *ArgPromotion::DoPromotion(Function *F, AA.replaceWithNewValue(Call, New); // Update the callgraph to know that the callsite has been transformed. - CG[Call->getParent()->getParent()]->replaceCallSite(Call, New); + CallGraphNode *CalleeNode = CG[Call->getParent()->getParent()]; + CalleeNode->replaceCallEdge(Call, New, NF_CGN); if (!Call->use_empty()) { Call->replaceAllUsesWith(New); @@ -757,10 +771,11 @@ Function *ArgPromotion::DoPromotion(Function *F, const Type *AgTy = cast(I->getType())->getElementType(); Value *TheAlloca = new AllocaInst(AgTy, 0, "", InsertPt); const StructType *STy = cast(AgTy); - Value *Idxs[2] = { ConstantInt::get(Type::Int32Ty, 0), 0 }; + 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::Int32Ty, i); + Idxs[1] = ConstantInt::get(Type::getInt32Ty(F->getContext()), i); Value *Idx = GetElementPtrInst::Create(TheAlloca, Idxs, Idxs+2, TheAlloca->getName()+"."+Twine(i), @@ -794,7 +809,7 @@ Function *ArgPromotion::DoPromotion(Function *F, LI->replaceAllUsesWith(I2); AA.replaceWithNewValue(LI, I2); LI->eraseFromParent(); - DEBUG(errs() << "*** Promoted load of argument '" << I->getName() + DEBUG(dbgs() << "*** Promoted load of argument '" << I->getName() << "' in function '" << F->getName() << "'\n"); } else { GetElementPtrInst *GEP = cast(I->use_back()); @@ -821,7 +836,7 @@ Function *ArgPromotion::DoPromotion(Function *F, NewName += ".val"; TheArg->setName(NewName); - DEBUG(errs() << "*** Promoted agg argument '" << TheArg->getName() + DEBUG(dbgs() << "*** Promoted agg argument '" << TheArg->getName() << "' of function '" << NF->getName() << "'\n"); // All of the uses must be load instructions. Replace them all with @@ -844,13 +859,24 @@ Function *ArgPromotion::DoPromotion(Function *F, // Notify the alias analysis implementation that we inserted a new argument. if (ExtraArgHack) - AA.copyValue(Constant::getNullValue(Type::Int32Ty), NF->arg_begin()); + 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); - // Now that the old function is dead, delete it. - F->eraseFromParent(); - return 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; }