1894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman//===-- ArgumentPromotion.cpp - Promote by-reference arguments ------------===// 2894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// 3894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// The LLVM Compiler Infrastructure 4894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// 5894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// This file is distributed under the University of Illinois Open Source 6894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// License. See LICENSE.TXT for details. 7894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// 8894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman//===----------------------------------------------------------------------===// 9894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// 10894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// This pass promotes "by reference" arguments to be "by value" arguments. In 11894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// practice, this means looking for internal functions that have pointer 12894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// arguments. If it can prove, through the use of alias analysis, that an 13894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// argument is *only* loaded, then it can pass the value into the function 14894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// instead of the address of the value. This can cause recursive simplification 15894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// of code and lead to the elimination of allocas (especially in C++ template 16894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// code like the STL). 17894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// 18894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// This pass also handles aggregate arguments that are passed into a function, 19894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// scalarizing them if the elements of the aggregate are only loaded. Note that 20894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// by default it refuses to scalarize aggregates which would require passing in 21894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// more than three operands to the function, because passing thousands of 22894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// operands for a large array or structure is unprofitable! This limit can be 23894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// configured or disabled, however. 24894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// 25894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// Note that this transformation could also be done for arguments that are only 26894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// stored to (returning the value instead), but does not currently. This case 27894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// would be best handled when and if LLVM begins supporting multiple return 28894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// values from functions. 29894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman// 30894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman//===----------------------------------------------------------------------===// 31894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 32894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#define DEBUG_TYPE "argpromotion" 33894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/Transforms/IPO.h" 34894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/Constants.h" 35894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/DerivedTypes.h" 36894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/Module.h" 37894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/CallGraphSCCPass.h" 38894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/Instructions.h" 39894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/LLVMContext.h" 40894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/Analysis/AliasAnalysis.h" 41894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/Analysis/CallGraph.h" 42894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/Support/CallSite.h" 43894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/Support/CFG.h" 44894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/Support/Debug.h" 45894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/Support/raw_ostream.h" 46894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/ADT/DepthFirstIterator.h" 47894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/ADT/Statistic.h" 48894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include "llvm/ADT/StringExtras.h" 49894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman#include <set> 50894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Baumanusing namespace llvm; 51894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 52894018228b0e0bdbd7aa7e8f47d4a9458789ca82John BaumanSTATISTIC(NumArgumentsPromoted , "Number of pointer arguments promoted"); 53894018228b0e0bdbd7aa7e8f47d4a9458789ca82John BaumanSTATISTIC(NumAggregatesPromoted, "Number of aggregate arguments promoted"); 54894018228b0e0bdbd7aa7e8f47d4a9458789ca82John BaumanSTATISTIC(NumByValArgsPromoted , "Number of byval arguments promoted"); 55894018228b0e0bdbd7aa7e8f47d4a9458789ca82John BaumanSTATISTIC(NumArgumentsDead , "Number of dead pointer args eliminated"); 56894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 57894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Baumannamespace { 58894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman /// ArgPromotion - The 'by reference' to 'by value' argument promotion pass. 59894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman /// 60894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman struct ArgPromotion : public CallGraphSCCPass { 61894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman virtual void getAnalysisUsage(AnalysisUsage &AU) const { 62894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AU.addRequired<AliasAnalysis>(); 63894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CallGraphSCCPass::getAnalysisUsage(AU); 64894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 65894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 66894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman virtual bool runOnSCC(CallGraphSCC &SCC); 67894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman static char ID; // Pass identification, replacement for typeid 68894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman explicit ArgPromotion(unsigned maxElements = 3) 6919bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman : CallGraphSCCPass(ID), maxElements(maxElements) { 7019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman initializeArgPromotionPass(*PassRegistry::getPassRegistry()); 7119bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman } 72894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 73894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman /// A vector used to hold the indices of a single GEP instruction 74894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman typedef std::vector<uint64_t> IndicesVector; 75894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 76894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman private: 77894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CallGraphNode *PromoteArguments(CallGraphNode *CGN); 78894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman bool isSafeToPromoteArgument(Argument *Arg, bool isByVal) const; 79894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CallGraphNode *DoPromotion(Function *F, 80894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallPtrSet<Argument*, 8> &ArgsToPromote, 81894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallPtrSet<Argument*, 8> &ByValArgsToTransform); 82894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman /// The maximum number of elements to expand, or 0 for unlimited. 83894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman unsigned maxElements; 84894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman }; 85894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman} 86894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 87894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Baumanchar ArgPromotion::ID = 0; 8819bac1e08be200c31efd26f0f5fd144c9b3eefd3John BaumanINITIALIZE_PASS_BEGIN(ArgPromotion, "argpromotion", 8919bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman "Promote 'by reference' arguments to scalars", false, false) 9019bac1e08be200c31efd26f0f5fd144c9b3eefd3John BaumanINITIALIZE_AG_DEPENDENCY(AliasAnalysis) 9119bac1e08be200c31efd26f0f5fd144c9b3eefd3John BaumanINITIALIZE_AG_DEPENDENCY(CallGraph) 9219bac1e08be200c31efd26f0f5fd144c9b3eefd3John BaumanINITIALIZE_PASS_END(ArgPromotion, "argpromotion", 9319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman "Promote 'by reference' arguments to scalars", false, false) 94894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 95894018228b0e0bdbd7aa7e8f47d4a9458789ca82John BaumanPass *llvm::createArgumentPromotionPass(unsigned maxElements) { 96894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return new ArgPromotion(maxElements); 97894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman} 98894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 99894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Baumanbool ArgPromotion::runOnSCC(CallGraphSCC &SCC) { 100894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman bool Changed = false, LocalChange; 101894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 102894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman do { // Iterate until we stop promoting from this SCC. 103894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman LocalChange = false; 104894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Attempt to promote arguments from all functions in this SCC. 105894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) { 106894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (CallGraphNode *CGN = PromoteArguments(*I)) { 107894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman LocalChange = true; 108894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SCC.ReplaceNode(*I, CGN); 109894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 110894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 111894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Changed |= LocalChange; // Remember that we changed something. 112894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } while (LocalChange); 113894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 114894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return Changed; 115894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman} 116894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 117894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// PromoteArguments - This method checks the specified function to see if there 118894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// are any promotable arguments and if it is safe to promote the function (for 119894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// example, all callers are direct). If safe to promote some arguments, it 120894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// calls the DoPromotion method. 121894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// 122894018228b0e0bdbd7aa7e8f47d4a9458789ca82John BaumanCallGraphNode *ArgPromotion::PromoteArguments(CallGraphNode *CGN) { 123894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Function *F = CGN->getFunction(); 124894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 125894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Make sure that it is local to this module. 126894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (!F || !F->hasLocalLinkage()) return 0; 127894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 128894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // First check: see if there are any pointer arguments! If not, quick exit. 129894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallVector<std::pair<Argument*, unsigned>, 16> PointerArgs; 130894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman unsigned ArgNo = 0; 131894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); 132894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman I != E; ++I, ++ArgNo) 133894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (I->getType()->isPointerTy()) 134894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman PointerArgs.push_back(std::pair<Argument*, unsigned>(I, ArgNo)); 135894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (PointerArgs.empty()) return 0; 136894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 137894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Second check: make sure that all callers are direct callers. We can't 13819bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // transform functions that have indirect callers. Also see if the function 13919bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // is self-recursive. 14019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman bool isSelfRecursive = false; 14119bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman for (Value::use_iterator UI = F->use_begin(), E = F->use_end(); 14219bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman UI != E; ++UI) { 14319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman CallSite CS(*UI); 14419bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // Must be a direct call. 14519bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (CS.getInstruction() == 0 || !CS.isCallee(UI)) return 0; 14619bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman 14719bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (CS.getInstruction()->getParent()->getParent() == F) 14819bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman isSelfRecursive = true; 14919bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman } 15019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman 151894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Check to see which arguments are promotable. If an argument is promotable, 152894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // add it to ArgsToPromote. 153894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallPtrSet<Argument*, 8> ArgsToPromote; 154894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallPtrSet<Argument*, 8> ByValArgsToTransform; 155894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (unsigned i = 0; i != PointerArgs.size(); ++i) { 156894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman bool isByVal = F->paramHasAttr(PointerArgs[i].second+1, Attribute::ByVal); 15719bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Argument *PtrArg = PointerArgs[i].first; 15819bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Type *AgTy = cast<PointerType>(PtrArg->getType())->getElementType(); 159894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 160894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // If this is a byval argument, and if the aggregate type is small, just 161894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // pass the elements, which is always safe. 162894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (isByVal) { 16319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (StructType *STy = dyn_cast<StructType>(AgTy)) { 164894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (maxElements > 0 && STy->getNumElements() > maxElements) { 165894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman DEBUG(dbgs() << "argpromotion disable promoting argument '" 166894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman << PtrArg->getName() << "' because it would require adding more" 167894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman << " than " << maxElements << " arguments to the function.\n"); 16819bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman continue; 16919bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman } 17019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman 17119bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // If all the elements are single-value types, we can promote it. 17219bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman bool AllSimple = true; 17319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { 17419bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (!STy->getElementType(i)->isSingleValueType()) { 17519bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman AllSimple = false; 17619bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman break; 177894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 178894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 17919bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman 18019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // Safe to transform, don't even bother trying to "promote" it. 18119bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // Passing the elements as a scalar will allow scalarrepl to hack on 18219bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // the new alloca we introduce. 18319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (AllSimple) { 18419bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman ByValArgsToTransform.insert(PtrArg); 18519bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman continue; 18619bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman } 187894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 188894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 189894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 19019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // If the argument is a recursive type and we're in a recursive 19119bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // function, we could end up infinitely peeling the function argument. 19219bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (isSelfRecursive) { 19319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (StructType *STy = dyn_cast<StructType>(AgTy)) { 19419bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman bool RecursiveType = false; 19519bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { 19619bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (STy->getElementType(i) == PtrArg->getType()) { 19719bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman RecursiveType = true; 19819bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman break; 19919bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman } 20019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman } 20119bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (RecursiveType) 20219bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman continue; 20319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman } 20419bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman } 20519bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman 206894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Otherwise, see if we can promote the pointer to its value. 207894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (isSafeToPromoteArgument(PtrArg, isByVal)) 208894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ArgsToPromote.insert(PtrArg); 209894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 210894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 211894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // No promotable pointer arguments. 212894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (ArgsToPromote.empty() && ByValArgsToTransform.empty()) 213894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return 0; 214894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 215894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return DoPromotion(F, ArgsToPromote, ByValArgsToTransform); 216894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman} 217894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 21819bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman/// AllCallersPassInValidPointerForArgument - Return true if we can prove that 219894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// all callees pass in a valid pointer for the specified function argument. 22019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Baumanstatic bool AllCallersPassInValidPointerForArgument(Argument *Arg) { 221894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Function *Callee = Arg->getParent(); 222894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 223894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman unsigned ArgNo = std::distance(Callee->arg_begin(), 224894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Function::arg_iterator(Arg)); 225894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 226894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Look at all call sites of the function. At this pointer we know we only 227894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // have direct callees. 228894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (Value::use_iterator UI = Callee->use_begin(), E = Callee->use_end(); 229894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman UI != E; ++UI) { 230894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CallSite CS(*UI); 231894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman assert(CS && "Should only have direct calls!"); 232894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 23319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (!CS.getArgument(ArgNo)->isDereferenceablePointer()) 234894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; 235894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 236894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return true; 237894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman} 238894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 239894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// Returns true if Prefix is a prefix of longer. That means, Longer has a size 240894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// that is greater than or equal to the size of prefix, and each of the 241894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// elements in Prefix is the same as the corresponding elements in Longer. 242894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// 243894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// This means it also returns true when Prefix and Longer are equal! 244894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Baumanstatic bool IsPrefix(const ArgPromotion::IndicesVector &Prefix, 245894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman const ArgPromotion::IndicesVector &Longer) { 246894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Prefix.size() > Longer.size()) 247894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; 248894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (unsigned i = 0, e = Prefix.size(); i != e; ++i) 249894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Prefix[i] != Longer[i]) 250894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; 251894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return true; 252894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman} 253894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 254894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 255894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// Checks if Indices, or a prefix of Indices, is in Set. 256894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Baumanstatic bool PrefixIn(const ArgPromotion::IndicesVector &Indices, 257894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman std::set<ArgPromotion::IndicesVector> &Set) { 258894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman std::set<ArgPromotion::IndicesVector>::iterator Low; 259894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Low = Set.upper_bound(Indices); 260894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Low != Set.begin()) 261894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Low--; 262894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Low is now the last element smaller than or equal to Indices. This means 263894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // it points to a prefix of Indices (possibly Indices itself), if such 264894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // prefix exists. 265894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // 266894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // This load is safe if any prefix of its operands is safe to load. 267894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return Low != Set.end() && IsPrefix(*Low, Indices); 268894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman} 269894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 270894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// Mark the given indices (ToMark) as safe in the given set of indices 271894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// (Safe). Marking safe usually means adding ToMark to Safe. However, if there 272894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// is already a prefix of Indices in Safe, Indices are implicitely marked safe 273894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// already. Furthermore, any indices that Indices is itself a prefix of, are 274894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// removed from Safe (since they are implicitely safe because of Indices now). 275894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Baumanstatic void MarkIndicesSafe(const ArgPromotion::IndicesVector &ToMark, 276894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman std::set<ArgPromotion::IndicesVector> &Safe) { 277894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman std::set<ArgPromotion::IndicesVector>::iterator Low; 278894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Low = Safe.upper_bound(ToMark); 279894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Guard against the case where Safe is empty 280894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Low != Safe.begin()) 281894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Low--; 282894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Low is now the last element smaller than or equal to Indices. This 283894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // means it points to a prefix of Indices (possibly Indices itself), if 284894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // such prefix exists. 285894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Low != Safe.end()) { 286894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (IsPrefix(*Low, ToMark)) 287894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // If there is already a prefix of these indices (or exactly these 288894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // indices) marked a safe, don't bother adding these indices 289894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return; 290894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 291894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Increment Low, so we can use it as a "insert before" hint 292894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++Low; 293894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 294894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Insert 295894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Low = Safe.insert(Low, ToMark); 296894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++Low; 297894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // If there we're a prefix of longer index list(s), remove those 298894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman std::set<ArgPromotion::IndicesVector>::iterator End = Safe.end(); 299894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman while (Low != End && IsPrefix(ToMark, *Low)) { 300894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman std::set<ArgPromotion::IndicesVector>::iterator Remove = Low; 301894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++Low; 302894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Safe.erase(Remove); 303894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 304894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman} 305894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 306894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// isSafeToPromoteArgument - As you might guess from the name of this method, 307894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// it checks to see if it is both safe and useful to promote the argument. 308894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// This method limits promotion of aggregates to only promote up to three 309894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// elements of the aggregate in order to avoid exploding the number of 310894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// arguments passed in. 311894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Baumanbool ArgPromotion::isSafeToPromoteArgument(Argument *Arg, bool isByVal) const { 312894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman typedef std::set<IndicesVector> GEPIndicesSet; 313894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 314894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Quick exit for unused arguments 315894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Arg->use_empty()) 316894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return true; 317894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 318894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // We can only promote this argument if all of the uses are loads, or are GEP 319894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // instructions (with constant indices) that are subsequently loaded. 320894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // 321894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Promoting the argument causes it to be loaded in the caller 322894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // unconditionally. This is only safe if we can prove that either the load 323894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // would have happened in the callee anyway (ie, there is a load in the entry 324894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // block) or the pointer passed in at every call site is guaranteed to be 325894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // valid. 326894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // In the former case, invalid loads can happen, but would have happened 327894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // anyway, in the latter case, invalid loads won't happen. This prevents us 328894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // from introducing an invalid load that wouldn't have happened in the 329894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // original code. 330894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // 331894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // This set will contain all sets of indices that are loaded in the entry 332894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // block, and thus are safe to unconditionally load in the caller. 333894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman GEPIndicesSet SafeToUnconditionallyLoad; 334894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 335894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // This set contains all the sets of indices that we are planning to promote. 336894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // This makes it possible to limit the number of arguments added. 337894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman GEPIndicesSet ToPromote; 338894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 339894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // If the pointer is always valid, any load with first index 0 is valid. 34019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (isByVal || AllCallersPassInValidPointerForArgument(Arg)) 341894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SafeToUnconditionallyLoad.insert(IndicesVector(1, 0)); 342894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 343894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // First, iterate the entry block and mark loads of (geps of) arguments as 344894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // safe. 345894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman BasicBlock *EntryBlock = Arg->getParent()->begin(); 346894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Declare this here so we can reuse it 347894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman IndicesVector Indices; 348894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (BasicBlock::iterator I = EntryBlock->begin(), E = EntryBlock->end(); 349894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman I != E; ++I) 350894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (LoadInst *LI = dyn_cast<LoadInst>(I)) { 351894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Value *V = LI->getPointerOperand(); 352894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V)) { 353894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman V = GEP->getPointerOperand(); 354894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (V == Arg) { 355894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // This load actually loads (part of) Arg? Check the indices then. 356894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Indices.reserve(GEP->getNumIndices()); 357894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (User::op_iterator II = GEP->idx_begin(), IE = GEP->idx_end(); 358894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman II != IE; ++II) 359894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (ConstantInt *CI = dyn_cast<ConstantInt>(*II)) 360894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Indices.push_back(CI->getSExtValue()); 361894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman else 362894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // We found a non-constant GEP index for this argument? Bail out 363894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // right away, can't promote this argument at all. 364894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; 365894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 366894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Indices checked out, mark them as safe 367894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman MarkIndicesSafe(Indices, SafeToUnconditionallyLoad); 368894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Indices.clear(); 369894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 370894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else if (V == Arg) { 371894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Direct loads are equivalent to a GEP with a single 0 index. 372894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman MarkIndicesSafe(IndicesVector(1, 0), SafeToUnconditionallyLoad); 373894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 374894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 375894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 376894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Now, iterate all uses of the argument to see if there are any uses that are 377894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // not (GEP+)loads, or any (GEP+)loads that are not safe to promote. 378894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallVector<LoadInst*, 16> Loads; 379894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman IndicesVector Operands; 380894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (Value::use_iterator UI = Arg->use_begin(), E = Arg->use_end(); 381894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman UI != E; ++UI) { 382894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman User *U = *UI; 383894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Operands.clear(); 384894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (LoadInst *LI = dyn_cast<LoadInst>(U)) { 38519bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // Don't hack volatile/atomic loads 38619bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (!LI->isSimple()) return false; 387894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Loads.push_back(LI); 388894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Direct loads are equivalent to a GEP with a zero index and then a load. 389894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Operands.push_back(0); 390894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) { 391894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (GEP->use_empty()) { 392894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Dead GEP's cause trouble later. Just remove them if we run into 393894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // them. 394894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman getAnalysis<AliasAnalysis>().deleteValue(GEP); 395894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman GEP->eraseFromParent(); 396894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // TODO: This runs the above loop over and over again for dead GEPs 397894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Couldn't we just do increment the UI iterator earlier and erase the 398894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // use? 399894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return isSafeToPromoteArgument(Arg, isByVal); 400894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 401894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 402894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Ensure that all of the indices are constants. 403894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (User::op_iterator i = GEP->idx_begin(), e = GEP->idx_end(); 404894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman i != e; ++i) 405894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (ConstantInt *C = dyn_cast<ConstantInt>(*i)) 406894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Operands.push_back(C->getSExtValue()); 407894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman else 408894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; // Not a constant operand GEP! 409894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 410894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Ensure that the only users of the GEP are load instructions. 411894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (Value::use_iterator UI = GEP->use_begin(), E = GEP->use_end(); 412894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman UI != E; ++UI) 413894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 41419bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // Don't hack volatile/atomic loads 41519bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (!LI->isSimple()) return false; 416894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Loads.push_back(LI); 417894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else { 418894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Other uses than load? 419894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; 420894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 421894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else { 422894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; // Not a load or a GEP. 423894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 424894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 425894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Now, see if it is safe to promote this load / loads of this GEP. Loading 426894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // is safe if Operands, or a prefix of Operands, is marked as safe. 427894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (!PrefixIn(Operands, SafeToUnconditionallyLoad)) 428894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; 429894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 430894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // See if we are already promoting a load with these indices. If not, check 431894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // to make sure that we aren't promoting too many elements. If so, nothing 432894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // to do. 433894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (ToPromote.find(Operands) == ToPromote.end()) { 434894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (maxElements > 0 && ToPromote.size() == maxElements) { 435894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman DEBUG(dbgs() << "argpromotion not promoting argument '" 436894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman << Arg->getName() << "' because it would require adding more " 437894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman << "than " << maxElements << " arguments to the function.\n"); 438894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // We limit aggregate promotion to only promoting up to a fixed number 439894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // of elements of the aggregate. 440894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; 441894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 442894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ToPromote.insert(Operands); 443894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 444894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 445894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 446894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Loads.empty()) return true; // No users, this is a dead argument. 447894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 448894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Okay, now we know that the argument is only used by load instructions and 449894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // it is safe to unconditionally perform all of them. Use alias analysis to 450894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // check to see if the pointer is guaranteed to not be modified from entry of 451894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // the function to each of the load instructions. 452894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 453894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Because there could be several/many load instructions, remember which 454894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // blocks we know to be transparent to the load. 455894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallPtrSet<BasicBlock*, 16> TranspBlocks; 456894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 457894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 458894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 459894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (unsigned i = 0, e = Loads.size(); i != e; ++i) { 460894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Check to see if the load is invalidated from the start of the block to 461894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // the load itself. 462894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman LoadInst *Load = Loads[i]; 463894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman BasicBlock *BB = Load->getParent(); 464894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 46519bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman AliasAnalysis::Location Loc = AA.getLocation(Load); 46619bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (AA.canInstructionRangeModify(BB->front(), *Load, Loc)) 467894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; // Pointer is invalidated! 468894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 469894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Now check every path from the entry block to the load for transparency. 470894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // To do this, we perform a depth first search on the inverse CFG from the 471894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // loading block. 472894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) { 473894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman BasicBlock *P = *PI; 474894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (idf_ext_iterator<BasicBlock*, SmallPtrSet<BasicBlock*, 16> > 475894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman I = idf_ext_begin(P, TranspBlocks), 476894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman E = idf_ext_end(P, TranspBlocks); I != E; ++I) 47719bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman if (AA.canBasicBlockModify(**I, Loc)) 478894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return false; 479894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 480894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 481894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 482894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // If the path from the entry of the function to each load is free of 483894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // instructions that potentially invalidate the load, we can make the 484894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // transformation! 485894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return true; 486894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman} 487894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 488894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// DoPromotion - This method actually performs the promotion of the specified 489894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// arguments, and returns the new function. At this point, we know that it's 490894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman/// safe to do so. 491894018228b0e0bdbd7aa7e8f47d4a9458789ca82John BaumanCallGraphNode *ArgPromotion::DoPromotion(Function *F, 492894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallPtrSet<Argument*, 8> &ArgsToPromote, 493894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallPtrSet<Argument*, 8> &ByValArgsToTransform) { 494894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 495894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Start by computing a new prototype for the function, which is the same as 496894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // the old function, but has modified arguments. 49719bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman FunctionType *FTy = F->getFunctionType(); 49819bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman std::vector<Type*> Params; 499894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 500894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman typedef std::set<IndicesVector> ScalarizeTable; 501894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 502894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // ScalarizedElements - If we are promoting a pointer that has elements 503894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // accessed out of it, keep track of which elements are accessed so that we 504894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // can add one argument for each. 505894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // 506894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Arguments that are directly loaded will have a zero element value here, to 507894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // handle cases where there are both a direct load and GEP accesses. 508894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // 509894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman std::map<Argument*, ScalarizeTable> ScalarizedElements; 510894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 511894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // OriginalLoads - Keep track of a representative load instruction from the 512894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // original function so that we can tell the alias analysis implementation 513894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // what the new GEP/Load instructions we are inserting look like. 514894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman std::map<IndicesVector, LoadInst*> OriginalLoads; 515894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 516894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Attributes - Keep track of the parameter attributes for the arguments 517894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // that we are *not* promoting. For the ones that we do promote, the parameter 518894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // attributes are lost 519894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallVector<AttributeWithIndex, 8> AttributesVec; 520894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman const AttrListPtr &PAL = F->getAttributes(); 521894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 522894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Add any return attributes. 523894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Attributes attrs = PAL.getRetAttributes()) 524894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.push_back(AttributeWithIndex::get(0, attrs)); 525894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 526894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // First, determine the new argument list 527894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman unsigned ArgIndex = 1; 528894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; 529894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++I, ++ArgIndex) { 530894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (ByValArgsToTransform.count(I)) { 531894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Simple byval argument? Just add all the struct element types. 53219bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Type *AgTy = cast<PointerType>(I->getType())->getElementType(); 53319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman StructType *STy = cast<StructType>(AgTy); 534894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) 535894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Params.push_back(STy->getElementType(i)); 536894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++NumByValArgsPromoted; 537894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else if (!ArgsToPromote.count(I)) { 538894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Unchanged argument 539894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Params.push_back(I->getType()); 540894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Attributes attrs = PAL.getParamAttributes(ArgIndex)) 541894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.push_back(AttributeWithIndex::get(Params.size(), attrs)); 542894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else if (I->use_empty()) { 543894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Dead argument (which are always marked as promotable) 544894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++NumArgumentsDead; 545894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else { 546894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Okay, this is being promoted. This means that the only uses are loads 547894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // or GEPs which are only used by loads 548894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 549894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // In this table, we will track which indices are loaded from the argument 550894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // (where direct loads are tracked as no indices). 551894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ScalarizeTable &ArgIndices = ScalarizedElements[I]; 552894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; 553894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++UI) { 554894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Instruction *User = cast<Instruction>(*UI); 555894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman assert(isa<LoadInst>(User) || isa<GetElementPtrInst>(User)); 556894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman IndicesVector Indices; 557894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Indices.reserve(User->getNumOperands() - 1); 558894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Since loads will only have a single operand, and GEPs only a single 559894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // non-index operand, this will record direct loads without any indices, 560894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // and gep+loads with the GEP indices. 561894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (User::op_iterator II = User->op_begin() + 1, IE = User->op_end(); 562894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman II != IE; ++II) 563894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Indices.push_back(cast<ConstantInt>(*II)->getSExtValue()); 564894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // GEPs with a single 0 index can be merged with direct loads 565894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Indices.size() == 1 && Indices.front() == 0) 566894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Indices.clear(); 567894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ArgIndices.insert(Indices); 568894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman LoadInst *OrigLoad; 569894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (LoadInst *L = dyn_cast<LoadInst>(User)) 570894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman OrigLoad = L; 571894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman else 572894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Take any load, we will use it only to update Alias Analysis 573894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman OrigLoad = cast<LoadInst>(User->use_back()); 574894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman OriginalLoads[Indices] = OrigLoad; 575894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 576894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 577894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Add a parameter to the function for each element passed in. 578894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (ScalarizeTable::iterator SI = ArgIndices.begin(), 579894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman E = ArgIndices.end(); SI != E; ++SI) { 580894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // not allowed to dereference ->begin() if size() is 0 58119bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Params.push_back(GetElementPtrInst::getIndexedType(I->getType(), *SI)); 582894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman assert(Params.back()); 583894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 584894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 585894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (ArgIndices.size() == 1 && ArgIndices.begin()->empty()) 586894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++NumArgumentsPromoted; 587894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman else 588894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++NumAggregatesPromoted; 589894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 590894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 591894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 592894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Add any function attributes. 593894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Attributes attrs = PAL.getFnAttributes()) 594894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.push_back(AttributeWithIndex::get(~0, attrs)); 595894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 59619bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Type *RetTy = FTy->getReturnType(); 597894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 598894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Work around LLVM bug PR56: the CWriter cannot emit varargs functions which 599894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // have zero fixed arguments. 600894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman bool ExtraArgHack = false; 601894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Params.empty() && FTy->isVarArg()) { 602894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ExtraArgHack = true; 603894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Params.push_back(Type::getInt32Ty(F->getContext())); 604894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 605894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 606894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Construct the new function type using the new arguments. 607894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg()); 608894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 609894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Create the new function body and insert it into the module. 610894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Function *NF = Function::Create(NFTy, F->getLinkage(), F->getName()); 611894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman NF->copyAttributesFrom(F); 612894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 613894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 614894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman DEBUG(dbgs() << "ARG PROMOTION: Promoting to:" << *NF << "\n" 615894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman << "From: " << *F); 616894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 617894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Recompute the parameter attributes list based on the new arguments for 618894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // the function. 619894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman NF->setAttributes(AttrListPtr::get(AttributesVec.begin(), 620894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.end())); 621894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.clear(); 622894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 623894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman F->getParent()->getFunctionList().insert(F, NF); 624894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman NF->takeName(F); 625894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 626894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Get the alias analysis information that we need to update to reflect our 627894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // changes. 628894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 629894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 630894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Get the callgraph information that we need to update to reflect our 631894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // changes. 632894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CallGraph &CG = getAnalysis<CallGraph>(); 633894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 634894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Get a new callgraph node for NF. 635894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CallGraphNode *NF_CGN = CG.getOrInsertFunction(NF); 636894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 637894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Loop over all of the callers of the function, transforming the call sites 638894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // to pass in the loaded pointers. 639894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // 640894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman SmallVector<Value*, 16> Args; 641894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman while (!F->use_empty()) { 642894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CallSite CS(F->use_back()); 643894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman assert(CS.getCalledFunction() == F); 644894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Instruction *Call = CS.getInstruction(); 645894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman const AttrListPtr &CallPAL = CS.getAttributes(); 646894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 647894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Add any return attributes. 648894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Attributes attrs = CallPAL.getRetAttributes()) 649894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.push_back(AttributeWithIndex::get(0, attrs)); 650894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 651894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Loop over the operands, inserting GEP and loads in the caller as 652894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // appropriate. 653894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CallSite::arg_iterator AI = CS.arg_begin(); 654894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ArgIndex = 1; 655894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); 656894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman I != E; ++I, ++AI, ++ArgIndex) 657894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (!ArgsToPromote.count(I) && !ByValArgsToTransform.count(I)) { 658894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Args.push_back(*AI); // Unmodified argument 659894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 660894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Attributes Attrs = CallPAL.getParamAttributes(ArgIndex)) 661894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.push_back(AttributeWithIndex::get(Args.size(), Attrs)); 662894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 663894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else if (ByValArgsToTransform.count(I)) { 664894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Emit a GEP and load for each element of the struct. 66519bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Type *AgTy = cast<PointerType>(I->getType())->getElementType(); 66619bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman StructType *STy = cast<StructType>(AgTy); 667894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Value *Idxs[2] = { 668894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ConstantInt::get(Type::getInt32Ty(F->getContext()), 0), 0 }; 669894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { 670894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Idxs[1] = ConstantInt::get(Type::getInt32Ty(F->getContext()), i); 67119bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Value *Idx = GetElementPtrInst::Create(*AI, Idxs, 672894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman (*AI)->getName()+"."+utostr(i), 673894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Call); 674894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // TODO: Tell AA about the new values? 675894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Args.push_back(new LoadInst(Idx, Idx->getName()+".val", Call)); 676894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 677894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else if (!I->use_empty()) { 678894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Non-dead argument: insert GEPs and loads as appropriate. 679894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ScalarizeTable &ArgIndices = ScalarizedElements[I]; 680894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Store the Value* version of the indices in here, but declare it now 681894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // for reuse. 682894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman std::vector<Value*> Ops; 683894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (ScalarizeTable::iterator SI = ArgIndices.begin(), 684894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman E = ArgIndices.end(); SI != E; ++SI) { 685894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Value *V = *AI; 686894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman LoadInst *OrigLoad = OriginalLoads[*SI]; 687894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (!SI->empty()) { 688894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Ops.reserve(SI->size()); 68919bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Type *ElTy = V->getType(); 690894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (IndicesVector::const_iterator II = SI->begin(), 691894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman IE = SI->end(); II != IE; ++II) { 692894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Use i32 to index structs, and i64 for others (pointers/arrays). 693894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // This satisfies GEP constraints. 69419bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Type *IdxTy = (ElTy->isStructTy() ? 695894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Type::getInt32Ty(F->getContext()) : 696894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Type::getInt64Ty(F->getContext())); 697894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Ops.push_back(ConstantInt::get(IdxTy, *II)); 698894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Keep track of the type we're currently indexing. 699894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ElTy = cast<CompositeType>(ElTy)->getTypeAtIndex(*II); 700894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 701894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // And create a GEP to extract those indices. 70219bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman V = GetElementPtrInst::Create(V, Ops, V->getName()+".idx", Call); 703894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Ops.clear(); 704894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.copyValue(OrigLoad->getOperand(0), V); 705894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 706894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Since we're replacing a load make sure we take the alignment 707894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // of the previous load. 708894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman LoadInst *newLoad = new LoadInst(V, V->getName()+".val", Call); 709894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman newLoad->setAlignment(OrigLoad->getAlignment()); 71019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // Transfer the TBAA info too. 71119bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman newLoad->setMetadata(LLVMContext::MD_tbaa, 71219bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman OrigLoad->getMetadata(LLVMContext::MD_tbaa)); 713894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Args.push_back(newLoad); 714894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.copyValue(OrigLoad, Args.back()); 715894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 716894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 717894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 718894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (ExtraArgHack) 719894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Args.push_back(Constant::getNullValue(Type::getInt32Ty(F->getContext()))); 720894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 721894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Push any varargs arguments on the list. 722894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (; AI != CS.arg_end(); ++AI, ++ArgIndex) { 723894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Args.push_back(*AI); 724894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Attributes Attrs = CallPAL.getParamAttributes(ArgIndex)) 725894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.push_back(AttributeWithIndex::get(Args.size(), Attrs)); 726894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 727894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 728894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Add any function attributes. 729894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Attributes attrs = CallPAL.getFnAttributes()) 730894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.push_back(AttributeWithIndex::get(~0, attrs)); 731894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 732894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Instruction *New; 733894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) { 734894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman New = InvokeInst::Create(NF, II->getNormalDest(), II->getUnwindDest(), 73519bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Args, "", Call); 736894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv()); 737894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman cast<InvokeInst>(New)->setAttributes(AttrListPtr::get(AttributesVec.begin(), 738894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.end())); 739894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else { 74019bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman New = CallInst::Create(NF, Args, "", Call); 741894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman cast<CallInst>(New)->setCallingConv(CS.getCallingConv()); 742894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman cast<CallInst>(New)->setAttributes(AttrListPtr::get(AttributesVec.begin(), 743894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.end())); 744894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (cast<CallInst>(Call)->isTailCall()) 745894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman cast<CallInst>(New)->setTailCall(); 746894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 747894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Args.clear(); 748894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AttributesVec.clear(); 749894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 750894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Update the alias analysis implementation to know that we are replacing 751894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // the old call with a new one. 752894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.replaceWithNewValue(Call, New); 753894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 754894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Update the callgraph to know that the callsite has been transformed. 755894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CallGraphNode *CalleeNode = CG[Call->getParent()->getParent()]; 756894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CalleeNode->replaceCallEdge(Call, New, NF_CGN); 757894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 758894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (!Call->use_empty()) { 759894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Call->replaceAllUsesWith(New); 760894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman New->takeName(Call); 761894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 762894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 763894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Finally, remove the old call from the program, reducing the use-count of 764894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // F. 765894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Call->eraseFromParent(); 766894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 767894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 768894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Since we have now created the new function, splice the body of the old 769894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // function right into the new function, leaving the old rotting hulk of the 770894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // function empty. 771894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList()); 772894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 77319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // Loop over the argument list, transferring uses of the old arguments over to 77419bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman // the new arguments, also transferring over the names as well. 775894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // 776894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(), 777894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman I2 = NF->arg_begin(); I != E; ++I) { 778894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (!ArgsToPromote.count(I) && !ByValArgsToTransform.count(I)) { 779894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // If this is an unmodified argument, move the name and users over to the 780894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // new version. 781894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman I->replaceAllUsesWith(I2); 782894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman I2->takeName(I); 783894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.replaceWithNewValue(I, I2); 784894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++I2; 785894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman continue; 786894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 787894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 788894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (ByValArgsToTransform.count(I)) { 789894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // In the callee, we create an alloca, and store each of the new incoming 790894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // arguments into the alloca. 791894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Instruction *InsertPt = NF->begin()->begin(); 792894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 793894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Just add all the struct element types. 79419bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman Type *AgTy = cast<PointerType>(I->getType())->getElementType(); 795894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Value *TheAlloca = new AllocaInst(AgTy, 0, "", InsertPt); 79619bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman StructType *STy = cast<StructType>(AgTy); 797894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Value *Idxs[2] = { 798894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ConstantInt::get(Type::getInt32Ty(F->getContext()), 0), 0 }; 799894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 800894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { 801894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Idxs[1] = ConstantInt::get(Type::getInt32Ty(F->getContext()), i); 802894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Value *Idx = 80319bac1e08be200c31efd26f0f5fd144c9b3eefd3John Bauman GetElementPtrInst::Create(TheAlloca, Idxs, 804894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman TheAlloca->getName()+"."+Twine(i), 805894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman InsertPt); 806894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman I2->setName(I->getName()+"."+Twine(i)); 807894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman new StoreInst(I2++, Idx, InsertPt); 808894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 809894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 810894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Anything that used the arg should now use the alloca. 811894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman I->replaceAllUsesWith(TheAlloca); 812894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman TheAlloca->takeName(I); 813894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.replaceWithNewValue(I, TheAlloca); 814894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman continue; 815894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 816894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 817894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (I->use_empty()) { 818894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.deleteValue(I); 819894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman continue; 820894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 821894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 822894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Otherwise, if we promoted this argument, then all users are load 823894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // instructions (or GEPs with only load users), and all loads should be 824894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // using the new argument that we added. 825894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ScalarizeTable &ArgIndices = ScalarizedElements[I]; 826894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 827894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman while (!I->use_empty()) { 828894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (LoadInst *LI = dyn_cast<LoadInst>(I->use_back())) { 829894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman assert(ArgIndices.begin()->empty() && 830894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman "Load element should sort to front!"); 831894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman I2->setName(I->getName()+".val"); 832894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman LI->replaceAllUsesWith(I2); 833894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.replaceWithNewValue(LI, I2); 834894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman LI->eraseFromParent(); 835894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman DEBUG(dbgs() << "*** Promoted load of argument '" << I->getName() 836894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman << "' in function '" << F->getName() << "'\n"); 837894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } else { 838894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->use_back()); 839894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman IndicesVector Operands; 840894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Operands.reserve(GEP->getNumIndices()); 841894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (User::op_iterator II = GEP->idx_begin(), IE = GEP->idx_end(); 842894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman II != IE; ++II) 843894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Operands.push_back(cast<ConstantInt>(*II)->getSExtValue()); 844894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 845894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // GEPs with a single 0 index can be merged with direct loads 846894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (Operands.size() == 1 && Operands.front() == 0) 847894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Operands.clear(); 848894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 849894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman Function::arg_iterator TheArg = I2; 850894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (ScalarizeTable::iterator It = ArgIndices.begin(); 851894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman *It != Operands; ++It, ++TheArg) { 852894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman assert(It != ArgIndices.end() && "GEP not handled??"); 853894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 854894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 855894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman std::string NewName = I->getName(); 856894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (unsigned i = 0, e = Operands.size(); i != e; ++i) { 857894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman NewName += "." + utostr(Operands[i]); 858894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 859894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman NewName += ".val"; 860894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman TheArg->setName(NewName); 861894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 862894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman DEBUG(dbgs() << "*** Promoted agg argument '" << TheArg->getName() 863894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman << "' of function '" << NF->getName() << "'\n"); 864894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 865894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // All of the uses must be load instructions. Replace them all with 866894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // the argument specified by ArgNo. 867894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman while (!GEP->use_empty()) { 868894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman LoadInst *L = cast<LoadInst>(GEP->use_back()); 869894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman L->replaceAllUsesWith(TheArg); 870894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.replaceWithNewValue(L, TheArg); 871894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman L->eraseFromParent(); 872894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 873894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.deleteValue(GEP); 874894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman GEP->eraseFromParent(); 875894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 876894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 877894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 878894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Increment I2 past all of the arguments added for this promoted pointer. 879894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman for (unsigned i = 0, e = ArgIndices.size(); i != e; ++i) 880894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman ++I2; 881894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman } 882894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 883894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Notify the alias analysis implementation that we inserted a new argument. 884894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (ExtraArgHack) 885894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.copyValue(Constant::getNullValue(Type::getInt32Ty(F->getContext())), 886894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman NF->arg_begin()); 887894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 888894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 889894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Tell the alias analysis that the old function is about to disappear. 890894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman AA.replaceWithNewValue(F, NF); 891894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 892894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 893894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman NF_CGN->stealCalledFunctionsFrom(CG[F]); 894894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 895894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // Now that the old function is dead, delete it. If there is a dangling 896894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // reference to the CallgraphNode, just leave the dead function around for 897894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman // someone else to nuke. 898894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman CallGraphNode *CGN = CG[F]; 899894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman if (CGN->getNumReferences() == 0) 900894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman delete CG.removeFunctionFromModule(CGN); 901894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman else 902894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman F->setLinkage(Function::ExternalLinkage); 903894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman 904894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman return NF_CGN; 905894018228b0e0bdbd7aa7e8f47d4a9458789ca82John Bauman} 906