X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FIPO%2FArgumentPromotion.cpp;h=fe30381170dc5006fbf2080a98ef2b9f360c2bc5;hb=4d70a2949007edeaad4662d5cdcb2d272cb2b2ff;hp=b1f7f045ac028594342777a58f19ad5f1b4a8fd5;hpb=a3512bd589ad9269ddaa4e9c008da43c36b4a1b8;p=oota-llvm.git diff --git a/lib/Transforms/IPO/ArgumentPromotion.cpp b/lib/Transforms/IPO/ArgumentPromotion.cpp index b1f7f045ac0..fe30381170d 100644 --- a/lib/Transforms/IPO/ArgumentPromotion.cpp +++ b/lib/Transforms/IPO/ArgumentPromotion.cpp @@ -39,9 +39,7 @@ #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" @@ -59,16 +57,18 @@ 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(); CallGraphSCCPass::getAnalysisUsage(AU); } - virtual bool runOnSCC(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; @@ -85,27 +85,32 @@ namespace { } 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(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) - if (CallGraphNode *CGN = PromoteArguments(SCC[i])) { + for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) { + if (CallGraphNode *CGN = PromoteArguments(*I)) { LocalChange = true; - SCC[i] = CGN; + SCC.ReplaceNode(*I, CGN); } + } Changed |= LocalChange; // Remember that we changed something. } while (LocalChange); - + return Changed; } @@ -125,7 +130,7 @@ CallGraphNode *ArgPromotion::PromoteArguments(CallGraphNode *CGN) { 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 0; @@ -148,7 +153,7 @@ CallGraphNode *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 { @@ -183,19 +188,6 @@ CallGraphNode *ArgPromotion::PromoteArguments(CallGraphNode *CGN) { return DoPromotion(F, ArgsToPromote, ByValArgsToTransform); } -/// 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; -} - /// AllCalleesPassInValidPointerForArgument - Return true if we can prove that /// all callees pass in a valid pointer for the specified function argument. static bool AllCalleesPassInValidPointerForArgument(Argument *Arg) { @@ -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 @@ -433,8 +426,6 @@ bool ArgPromotion::isSafeToPromoteArgument(Argument *Arg, bool isByVal) const { SmallPtrSet TranspBlocks; AliasAnalysis &AA = getAnalysis(); - TargetData *TD = getAnalysisIfAvailable(); - if (!TD) return false; // Without TargetData, assume the worst. 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 @@ -442,22 +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 @@ -589,17 +582,18 @@ CallGraphNode *ArgPromotion::DoPromotion(Function *F, // 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(errs() << "ARG PROMOTION: Promoting to:" << *NF << "\n" + 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); @@ -615,14 +609,14 @@ CallGraphNode *ArgPromotion::DoPromotion(Function *F, // 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(); @@ -660,7 +654,7 @@ CallGraphNode *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) { @@ -673,20 +667,27 @@ CallGraphNode *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) ? + 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()); } } @@ -694,7 +695,7 @@ CallGraphNode *ArgPromotion::DoPromotion(Function *F, if (ExtraArgHack) 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)) @@ -728,7 +729,8 @@ CallGraphNode *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, NF_CGN); + CallGraphNode *CalleeNode = CG[Call->getParent()->getParent()]; + CalleeNode->replaceCallEdge(Call, New, NF_CGN); if (!Call->use_empty()) { Call->replaceAllUsesWith(New); @@ -807,7 +809,7 @@ CallGraphNode *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()); @@ -834,7 +836,7 @@ CallGraphNode *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 @@ -867,8 +869,14 @@ CallGraphNode *ArgPromotion::DoPromotion(Function *F, NF_CGN->stealCalledFunctionsFrom(CG[F]); - // Now that the old function is dead, delete it. - delete CG.removeFunctionFromModule(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; }