ArgumentPromotion.cpp revision 514ab348fddcdffa8367685dc608b2f8d5de986d
19e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner//===-- ArgumentPromotion.cpp - Promote by-reference arguments ------------===// 2fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 3ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// The LLVM Compiler Infrastructure 4ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// 5ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// This file was developed by the LLVM research group and is distributed under 6ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// the University of Illinois Open Source License. See LICENSE.TXT for details. 7fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 8ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner//===----------------------------------------------------------------------===// 9ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// 10ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// This pass promotes "by reference" arguments to be "by value" arguments. In 11ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// practice, this means looking for internal functions that have pointer 1255cbec317d9c30c8ae1d35eaa008ca63d1f2fce9Gordon Henriksen// arguments. If it can prove, through the use of alias analysis, that an 1355cbec317d9c30c8ae1d35eaa008ca63d1f2fce9Gordon Henriksen// argument is *only* loaded, then it can pass the value into the function 14ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// instead of the address of the value. This can cause recursive simplification 159e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner// of code and lead to the elimination of allocas (especially in C++ template 169e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner// code like the STL). 17ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// 189440db886627161a8413e823797569fc7b10beafChris Lattner// This pass also handles aggregate arguments that are passed into a function, 199440db886627161a8413e823797569fc7b10beafChris Lattner// scalarizing them if the elements of the aggregate are only loaded. Note that 2055cbec317d9c30c8ae1d35eaa008ca63d1f2fce9Gordon Henriksen// it refuses to scalarize aggregates which would require passing in more than 2155cbec317d9c30c8ae1d35eaa008ca63d1f2fce9Gordon Henriksen// three operands to the function, because passing thousands of operands for a 2255cbec317d9c30c8ae1d35eaa008ca63d1f2fce9Gordon Henriksen// large array or structure is unprofitable! 239440db886627161a8413e823797569fc7b10beafChris Lattner// 24ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// Note that this transformation could also be done for arguments that are only 2555cbec317d9c30c8ae1d35eaa008ca63d1f2fce9Gordon Henriksen// stored to (returning the value instead), but does not currently. This case 2655cbec317d9c30c8ae1d35eaa008ca63d1f2fce9Gordon Henriksen// would be best handled when and if LLVM begins supporting multiple return 2755cbec317d9c30c8ae1d35eaa008ca63d1f2fce9Gordon Henriksen// values from functions. 28ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// 29ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner//===----------------------------------------------------------------------===// 30ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 319e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner#define DEBUG_TYPE "argpromotion" 32ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Transforms/IPO.h" 33ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Constants.h" 34ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/DerivedTypes.h" 35ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Module.h" 365eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner#include "llvm/CallGraphSCCPass.h" 37ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Instructions.h" 38ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Analysis/AliasAnalysis.h" 395eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner#include "llvm/Analysis/CallGraph.h" 40ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Target/TargetData.h" 41ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Support/CallSite.h" 42ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Support/CFG.h" 43551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/Debug.h" 44551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/DepthFirstIterator.h" 45551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/Statistic.h" 46551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/StringExtras.h" 479133fe28954d498fc4de13064c7d65bd811de02cReid Spencer#include "llvm/Support/Compiler.h" 48ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include <set> 49ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattnerusing namespace llvm; 50ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 5186453c52ba02e743d29c08456e51006500041456Chris LattnerSTATISTIC(NumArgumentsPromoted , "Number of pointer arguments promoted"); 5286453c52ba02e743d29c08456e51006500041456Chris LattnerSTATISTIC(NumAggregatesPromoted, "Number of aggregate arguments promoted"); 5386453c52ba02e743d29c08456e51006500041456Chris LattnerSTATISTIC(NumArgumentsDead , "Number of dead pointer args eliminated"); 54ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 5586453c52ba02e743d29c08456e51006500041456Chris Lattnernamespace { 56ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner /// ArgPromotion - The 'by reference' to 'by value' argument promotion pass. 57ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner /// 589133fe28954d498fc4de13064c7d65bd811de02cReid Spencer struct VISIBILITY_HIDDEN ArgPromotion : public CallGraphSCCPass { 59ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner virtual void getAnalysisUsage(AnalysisUsage &AU) const { 60ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner AU.addRequired<AliasAnalysis>(); 61ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner AU.addRequired<TargetData>(); 625eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner CallGraphSCCPass::getAnalysisUsage(AU); 63ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 64ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 655eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner virtual bool runOnSCC(const std::vector<CallGraphNode *> &SCC); 66ecd94c804a563f2a86572dcf1d2e81f397e19daaNick Lewycky static char ID; // Pass identification, replacement for typeid 67794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel ArgPromotion() : CallGraphSCCPass((intptr_t)&ID) {} 68794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel 69ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner private: 705eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner bool PromoteArguments(CallGraphNode *CGN); 71fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman bool isSafeToPromoteArgument(Argument *Arg) const; 725eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Function *DoPromotion(Function *F, std::vector<Argument*> &ArgsToPromote); 73ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner }; 74ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 751997473cf72957d0e70322e2fe6fe2ab141c58a6Devang Patel char ArgPromotion::ID = 0; 767f8897f22e88271cfa114998a4d6088e7c8e8e11Chris Lattner RegisterPass<ArgPromotion> X("argpromotion", 777f8897f22e88271cfa114998a4d6088e7c8e8e11Chris Lattner "Promote 'by reference' arguments to scalars"); 78ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 79ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 80c71ca3cdd2d7a08b043ebb717cad0beadaf47450Devang PatelPass *llvm::createArgumentPromotionPass() { 81ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return new ArgPromotion(); 82ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 83ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 845eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattnerbool ArgPromotion::runOnSCC(const std::vector<CallGraphNode *> &SCC) { 855eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner bool Changed = false, LocalChange; 86ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 87f5afcabff887c2e9023f0c69c44f1de15b5c4347Chris Lattner do { // Iterate until we stop promoting from this SCC. 885eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner LocalChange = false; 895eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Attempt to promote arguments from all functions in this SCC. 905eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner for (unsigned i = 0, e = SCC.size(); i != e; ++i) 915eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner LocalChange |= PromoteArguments(SCC[i]); 925eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Changed |= LocalChange; // Remember that we changed something. 935eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner } while (LocalChange); 94fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 95ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return Changed; 96ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 97ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 989e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// PromoteArguments - This method checks the specified function to see if there 999e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// are any promotable arguments and if it is safe to promote the function (for 1009e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// example, all callers are direct). If safe to promote some arguments, it 1019e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// calls the DoPromotion method. 1029e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// 1035eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattnerbool ArgPromotion::PromoteArguments(CallGraphNode *CGN) { 1045eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Function *F = CGN->getFunction(); 1055eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner 1065eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Make sure that it is local to this module. 1075eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner if (!F || !F->hasInternalLinkage()) return false; 108ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 109ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // First check: see if there are any pointer arguments! If not, quick exit. 110ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<Argument*> PointerArgs; 111e4d5c441e04bdc00ccf1804744af670655123b07Chris Lattner for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I) 112ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (isa<PointerType>(I->getType())) 113ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner PointerArgs.push_back(I); 114ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (PointerArgs.empty()) return false; 115ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 116ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Second check: make sure that all callers are direct callers. We can't 117ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // transform functions that have indirect callers. 118ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (Value::use_iterator UI = F->use_begin(), E = F->use_end(); 1197db5a6df78749bf0cd37870fcefe08b8849e38e6Chris Lattner UI != E; ++UI) { 1207db5a6df78749bf0cd37870fcefe08b8849e38e6Chris Lattner CallSite CS = CallSite::get(*UI); 1219e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (!CS.getInstruction()) // "Taking the address" of the function 1229e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner return false; 1239e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 1249e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Ensure that this call site is CALLING the function, not passing it as 1259e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // an argument. 1269e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end(); 1279e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AI != E; ++AI) 1289e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (*AI == F) return false; // Passing the function address in! 1297db5a6df78749bf0cd37870fcefe08b8849e38e6Chris Lattner } 130ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 131ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Check to see which arguments are promotable. If an argument is not 132ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // promotable, remove it from the PointerArgs vector. 133ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (unsigned i = 0; i != PointerArgs.size(); ++i) 134ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!isSafeToPromoteArgument(PointerArgs[i])) { 135ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::swap(PointerArgs[i--], PointerArgs.back()); 136ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner PointerArgs.pop_back(); 137ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 138ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 139ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // No promotable pointer arguments. 140ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (PointerArgs.empty()) return false; 141ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 142ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Okay, promote all of the arguments are rewrite the callees! 1435eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Function *NewF = DoPromotion(F, PointerArgs); 1445eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner 1455eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Update the call graph to know that the old function is gone. 1465eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner getAnalysis<CallGraph>().changeFunction(F, NewF); 147ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return true; 148ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 149ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 15011a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner/// IsAlwaysValidPointer - Return true if the specified pointer is always legal 15111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner/// to load. 15211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattnerstatic bool IsAlwaysValidPointer(Value *V) { 15311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner if (isa<AllocaInst>(V) || isa<GlobalVariable>(V)) return true; 15411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V)) 15511a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return IsAlwaysValidPointer(GEP->getOperand(0)); 15611a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) 15711a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner if (CE->getOpcode() == Instruction::GetElementPtr) 15811a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return IsAlwaysValidPointer(CE->getOperand(0)); 15911a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 16011a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return false; 16111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner} 16211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 16311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner/// AllCalleesPassInValidPointerForArgument - Return true if we can prove that 16411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner/// all callees pass in a valid pointer for the specified function argument. 16511a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattnerstatic bool AllCalleesPassInValidPointerForArgument(Argument *Arg) { 16611a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner Function *Callee = Arg->getParent(); 16711a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 16893e985f1b17aef62d58e3198a4604f9f6cfe8d19Chris Lattner unsigned ArgNo = std::distance(Callee->arg_begin(), 16993e985f1b17aef62d58e3198a4604f9f6cfe8d19Chris Lattner Function::arg_iterator(Arg)); 17011a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 17111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // Look at all call sites of the function. At this pointer we know we only 17211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // have direct callees. 17311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner for (Value::use_iterator UI = Callee->use_begin(), E = Callee->use_end(); 17411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner UI != E; ++UI) { 17511a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner CallSite CS = CallSite::get(*UI); 17611a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner assert(CS.getInstruction() && "Should only have direct calls!"); 17711a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 17811a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner if (!IsAlwaysValidPointer(CS.getArgument(ArgNo))) 17911a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return false; 18011a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner } 18111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return true; 18211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner} 18311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 1849e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 1859e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// isSafeToPromoteArgument - As you might guess from the name of this method, 1869e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// it checks to see if it is both safe and useful to promote the argument. 1879e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// This method limits promotion of aggregates to only promote up to three 1889e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// elements of the aggregate in order to avoid exploding the number of 1899e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// arguments passed in. 190ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattnerbool ArgPromotion::isSafeToPromoteArgument(Argument *Arg) const { 1919440db886627161a8413e823797569fc7b10beafChris Lattner // We can only promote this argument if all of the uses are loads, or are GEP 1929440db886627161a8413e823797569fc7b10beafChris Lattner // instructions (with constant indices) that are subsequently loaded. 19311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner bool HasLoadInEntryBlock = false; 19411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner BasicBlock *EntryBlock = Arg->getParent()->begin(); 195ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<LoadInst*> Loads; 196beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner std::vector<std::vector<ConstantInt*> > GEPIndices; 197ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (Value::use_iterator UI = Arg->use_begin(), E = Arg->use_end(); 198ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner UI != E; ++UI) 199ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 200ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (LI->isVolatile()) return false; // Don't hack volatile loads 201ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Loads.push_back(LI); 20211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner HasLoadInEntryBlock |= LI->getParent() == EntryBlock; 2039440db886627161a8413e823797569fc7b10beafChris Lattner } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) { 2049440db886627161a8413e823797569fc7b10beafChris Lattner if (GEP->use_empty()) { 2059440db886627161a8413e823797569fc7b10beafChris Lattner // Dead GEP's cause trouble later. Just remove them if we run into 2069440db886627161a8413e823797569fc7b10beafChris Lattner // them. 2079e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner getAnalysis<AliasAnalysis>().deleteValue(GEP); 2089440db886627161a8413e823797569fc7b10beafChris Lattner GEP->getParent()->getInstList().erase(GEP); 2099440db886627161a8413e823797569fc7b10beafChris Lattner return isSafeToPromoteArgument(Arg); 2109440db886627161a8413e823797569fc7b10beafChris Lattner } 2119440db886627161a8413e823797569fc7b10beafChris Lattner // Ensure that all of the indices are constants. 212beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner std::vector<ConstantInt*> Operands; 2139440db886627161a8413e823797569fc7b10beafChris Lattner for (unsigned i = 1, e = GEP->getNumOperands(); i != e; ++i) 214beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner if (ConstantInt *C = dyn_cast<ConstantInt>(GEP->getOperand(i))) 2159440db886627161a8413e823797569fc7b10beafChris Lattner Operands.push_back(C); 2169440db886627161a8413e823797569fc7b10beafChris Lattner else 2179440db886627161a8413e823797569fc7b10beafChris Lattner return false; // Not a constant operand GEP! 2189440db886627161a8413e823797569fc7b10beafChris Lattner 2199440db886627161a8413e823797569fc7b10beafChris Lattner // Ensure that the only users of the GEP are load instructions. 2209440db886627161a8413e823797569fc7b10beafChris Lattner for (Value::use_iterator UI = GEP->use_begin(), E = GEP->use_end(); 2219440db886627161a8413e823797569fc7b10beafChris Lattner UI != E; ++UI) 2229440db886627161a8413e823797569fc7b10beafChris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 2239440db886627161a8413e823797569fc7b10beafChris Lattner if (LI->isVolatile()) return false; // Don't hack volatile loads 2249440db886627161a8413e823797569fc7b10beafChris Lattner Loads.push_back(LI); 22511a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner HasLoadInEntryBlock |= LI->getParent() == EntryBlock; 2269440db886627161a8413e823797569fc7b10beafChris Lattner } else { 2279440db886627161a8413e823797569fc7b10beafChris Lattner return false; 2289440db886627161a8413e823797569fc7b10beafChris Lattner } 229ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 2309e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // See if there is already a GEP with these indices. If not, check to 2319e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // make sure that we aren't promoting too many elements. If so, nothing 2329e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // to do. 2339440db886627161a8413e823797569fc7b10beafChris Lattner if (std::find(GEPIndices.begin(), GEPIndices.end(), Operands) == 2349440db886627161a8413e823797569fc7b10beafChris Lattner GEPIndices.end()) { 2359440db886627161a8413e823797569fc7b10beafChris Lattner if (GEPIndices.size() == 3) { 2360a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling DOUT << "argpromotion disable promoting argument '" 2370a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling << Arg->getName() << "' because it would require adding more " 2380a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling << "than 3 arguments to the function.\n"; 2399440db886627161a8413e823797569fc7b10beafChris Lattner // We limit aggregate promotion to only promoting up to three elements 2409440db886627161a8413e823797569fc7b10beafChris Lattner // of the aggregate. 2419440db886627161a8413e823797569fc7b10beafChris Lattner return false; 2429440db886627161a8413e823797569fc7b10beafChris Lattner } 2439440db886627161a8413e823797569fc7b10beafChris Lattner GEPIndices.push_back(Operands); 2449440db886627161a8413e823797569fc7b10beafChris Lattner } 2459440db886627161a8413e823797569fc7b10beafChris Lattner } else { 2469440db886627161a8413e823797569fc7b10beafChris Lattner return false; // Not a load or a GEP. 2479440db886627161a8413e823797569fc7b10beafChris Lattner } 248ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 2499e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (Loads.empty()) return true; // No users, this is a dead argument. 250ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 25111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // If we decide that we want to promote this argument, the value is going to 25211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // be unconditionally loaded in all callees. This is only safe to do if the 25311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // pointer was going to be unconditionally loaded anyway (i.e. there is a load 25411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // of the pointer in the entry block of the function) or if we can prove that 25511a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // all pointers passed in are always to legal locations (for example, no null 25611a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // pointers are passed in, no pointers to free'd memory, etc). 25799435d32b3318f1b2f593f484ea9ba26804bf56cEvan Cheng if (!HasLoadInEntryBlock && !AllCalleesPassInValidPointerForArgument(Arg)) 25811a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return false; // Cannot prove that this is safe!! 25911a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 26011a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // Okay, now we know that the argument is only used by load instructions and 26111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // it is safe to unconditionally load the pointer. Use alias analysis to 26211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // check to see if the pointer is guaranteed to not be modified from entry of 26311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // the function to each of the load instructions. 264ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 265ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Because there could be several/many load instructions, remember which 266ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // blocks we know to be transparent to the load. 267ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::set<BasicBlock*> TranspBlocks; 26846f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson 26946f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 2709440db886627161a8413e823797569fc7b10beafChris Lattner TargetData &TD = getAnalysis<TargetData>(); 271ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 272ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (unsigned i = 0, e = Loads.size(); i != e; ++i) { 273ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Check to see if the load is invalidated from the start of the block to 274ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // the load itself. 275ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner LoadInst *Load = Loads[i]; 276ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner BasicBlock *BB = Load->getParent(); 2779440db886627161a8413e823797569fc7b10beafChris Lattner 2789440db886627161a8413e823797569fc7b10beafChris Lattner const PointerType *LoadTy = 2799440db886627161a8413e823797569fc7b10beafChris Lattner cast<PointerType>(Load->getOperand(0)->getType()); 280514ab348fddcdffa8367685dc608b2f8d5de986dDuncan Sands unsigned LoadSize = (unsigned)TD.getTypeStoreSize(LoadTy->getElementType()); 2819440db886627161a8413e823797569fc7b10beafChris Lattner 282ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (AA.canInstructionRangeModify(BB->front(), *Load, Arg, LoadSize)) 283ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return false; // Pointer is invalidated! 284ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 285ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Now check every path from the entry block to the load for transparency. 286ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // To do this, we perform a depth first search on the inverse CFG from the 287ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // loading block. 288ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) 289ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (idf_ext_iterator<BasicBlock*> I = idf_ext_begin(*PI, TranspBlocks), 290ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner E = idf_ext_end(*PI, TranspBlocks); I != E; ++I) 291ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (AA.canBasicBlockModify(**I, Arg, LoadSize)) 292ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return false; 293ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 294ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 295ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // If the path from the entry of the function to each load is free of 296ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // instructions that potentially invalidate the load, we can make the 297ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // transformation! 298ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return true; 299ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 300ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 301beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattnernamespace { 302beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner /// GEPIdxComparator - Provide a strong ordering for GEP indices. All Value* 303beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner /// elements are instances of ConstantInt. 304beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner /// 305beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner struct GEPIdxComparator { 306beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner bool operator()(const std::vector<Value*> &LHS, 307beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner const std::vector<Value*> &RHS) const { 308beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner unsigned idx = 0; 309beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (; idx < LHS.size() && idx < RHS.size(); ++idx) { 310beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner if (LHS[idx] != RHS[idx]) { 311b83eb6447ba155342598f0fabe1f08f5baa9164aReid Spencer return cast<ConstantInt>(LHS[idx])->getZExtValue() < 312b83eb6447ba155342598f0fabe1f08f5baa9164aReid Spencer cast<ConstantInt>(RHS[idx])->getZExtValue(); 313beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner } 314beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner } 315beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 316beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner // Return less than if we ran out of stuff in LHS and we didn't run out of 317beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner // stuff in RHS. 318beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner return idx == LHS.size() && idx != RHS.size(); 319beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner } 320beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner }; 321beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner} 322beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 323beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 3249e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// DoPromotion - This method actually performs the promotion of the specified 3255eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner/// arguments, and returns the new function. At this point, we know that it's 3265eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner/// safe to do so. 3275eb6f6c829ddfe353f94623aa1009c72be930497Chris LattnerFunction *ArgPromotion::DoPromotion(Function *F, 3285eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner std::vector<Argument*> &Args2Prom) { 329ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::set<Argument*> ArgsToPromote(Args2Prom.begin(), Args2Prom.end()); 330fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 331ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Start by computing a new prototype for the function, which is the same as 332ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // the old function, but has modified arguments. 333ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner const FunctionType *FTy = F->getFunctionType(); 334ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<const Type*> Params; 335ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 336beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner typedef std::set<std::vector<Value*>, GEPIdxComparator> ScalarizeTable; 337beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 3389440db886627161a8413e823797569fc7b10beafChris Lattner // ScalarizedElements - If we are promoting a pointer that has elements 3399440db886627161a8413e823797569fc7b10beafChris Lattner // accessed out of it, keep track of which elements are accessed so that we 3409440db886627161a8413e823797569fc7b10beafChris Lattner // can add one argument for each. 3419440db886627161a8413e823797569fc7b10beafChris Lattner // 3429440db886627161a8413e823797569fc7b10beafChris Lattner // Arguments that are directly loaded will have a zero element value here, to 3439440db886627161a8413e823797569fc7b10beafChris Lattner // handle cases where there are both a direct load and GEP accesses. 3449440db886627161a8413e823797569fc7b10beafChris Lattner // 345beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner std::map<Argument*, ScalarizeTable> ScalarizedElements; 3469440db886627161a8413e823797569fc7b10beafChris Lattner 3479e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // OriginalLoads - Keep track of a representative load instruction from the 3489e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // original function so that we can tell the alias analysis implementation 3499e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // what the new GEP/Load instructions we are inserting look like. 3509e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner std::map<std::vector<Value*>, LoadInst*> OriginalLoads; 3519e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 352e4d5c441e04bdc00ccf1804744af670655123b07Chris Lattner for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I) 353ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!ArgsToPromote.count(I)) { 354ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Params.push_back(I->getType()); 3559e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else if (I->use_empty()) { 3569e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner ++NumArgumentsDead; 3579e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else { 3589440db886627161a8413e823797569fc7b10beafChris Lattner // Okay, this is being promoted. Check to see if there are any GEP uses 3599440db886627161a8413e823797569fc7b10beafChris Lattner // of the argument. 360beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner ScalarizeTable &ArgIndices = ScalarizedElements[I]; 3619440db886627161a8413e823797569fc7b10beafChris Lattner for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; 3629440db886627161a8413e823797569fc7b10beafChris Lattner ++UI) { 3639440db886627161a8413e823797569fc7b10beafChris Lattner Instruction *User = cast<Instruction>(*UI); 36446f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson assert(isa<LoadInst>(User) || isa<GetElementPtrInst>(User)); 36546f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson std::vector<Value*> Indices(User->op_begin()+1, User->op_end()); 36646f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson ArgIndices.insert(Indices); 36746f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson LoadInst *OrigLoad; 36846f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson if (LoadInst *L = dyn_cast<LoadInst>(User)) 36946f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson OrigLoad = L; 37046f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson else 37146f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson OrigLoad = cast<LoadInst>(User->use_back()); 37246f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson OriginalLoads[Indices] = OrigLoad; 3739440db886627161a8413e823797569fc7b10beafChris Lattner } 3749440db886627161a8413e823797569fc7b10beafChris Lattner 3759440db886627161a8413e823797569fc7b10beafChris Lattner // Add a parameter to the function for each element passed in. 376beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (ScalarizeTable::iterator SI = ArgIndices.begin(), 3779440db886627161a8413e823797569fc7b10beafChris Lattner E = ArgIndices.end(); SI != E; ++SI) 3781ccd185cb49d81465a2901622e58ceae046d1d83Chris Lattner Params.push_back(GetElementPtrInst::getIndexedType(I->getType(), 379b8f74793b9d161bc666fe27fc92fe112b6ec169bDavid Greene SI->begin(), 380b8f74793b9d161bc666fe27fc92fe112b6ec169bDavid Greene SI->end())); 3819440db886627161a8413e823797569fc7b10beafChris Lattner 3829440db886627161a8413e823797569fc7b10beafChris Lattner if (ArgIndices.size() == 1 && ArgIndices.begin()->empty()) 3839440db886627161a8413e823797569fc7b10beafChris Lattner ++NumArgumentsPromoted; 3849440db886627161a8413e823797569fc7b10beafChris Lattner else 3859440db886627161a8413e823797569fc7b10beafChris Lattner ++NumAggregatesPromoted; 386ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 387ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 388ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner const Type *RetTy = FTy->getReturnType(); 389ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 390ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Work around LLVM bug PR56: the CWriter cannot emit varargs functions which 391ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // have zero fixed arguments. 392ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner bool ExtraArgHack = false; 393ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (Params.empty() && FTy->isVarArg()) { 394ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner ExtraArgHack = true; 395c5b206b6be61d0d933b98b6af5e22f42edd48ad1Reid Spencer Params.push_back(Type::Int32Ty); 396ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 397ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg()); 398fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 399ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Create the new function body and insert it into the module... 400ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Function *NF = new Function(NFTy, F->getLinkage(), F->getName()); 401f201dbc1a4a638659ec3916785196e2c204c7755Chris Lattner NF->setCallingConv(F->getCallingConv()); 402ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner F->getParent()->getFunctionList().insert(F, NF); 4039e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 4049e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Get the alias analysis information that we need to update to reflect our 4059e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // changes. 4069e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 4079e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 408ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Loop over all of the callers of the function, transforming the call sites 409ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // to pass in the loaded pointers. 410ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // 411ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<Value*> Args; 412ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner while (!F->use_empty()) { 413ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner CallSite CS = CallSite::get(F->use_back()); 414ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Instruction *Call = CS.getInstruction(); 415ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 4169e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Loop over the operands, inserting GEP and loads in the caller as 4179e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // appropriate. 418ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner CallSite::arg_iterator AI = CS.arg_begin(); 419f201dbc1a4a638659ec3916785196e2c204c7755Chris Lattner for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); 420f201dbc1a4a638659ec3916785196e2c204c7755Chris Lattner I != E; ++I, ++AI) 421ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!ArgsToPromote.count(I)) 422ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args.push_back(*AI); // Unmodified argument 423ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner else if (!I->use_empty()) { 4249e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Non-dead argument: insert GEPs and loads as appropriate. 425beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner ScalarizeTable &ArgIndices = ScalarizedElements[I]; 426beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (ScalarizeTable::iterator SI = ArgIndices.begin(), 4279440db886627161a8413e823797569fc7b10beafChris Lattner E = ArgIndices.end(); SI != E; ++SI) { 4289440db886627161a8413e823797569fc7b10beafChris Lattner Value *V = *AI; 4299e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner LoadInst *OrigLoad = OriginalLoads[*SI]; 4309e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (!SI->empty()) { 431b8f74793b9d161bc666fe27fc92fe112b6ec169bDavid Greene V = new GetElementPtrInst(V, SI->begin(), SI->end(), 4321ccd185cb49d81465a2901622e58ceae046d1d83Chris Lattner V->getName()+".idx", Call); 4339e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.copyValue(OrigLoad->getOperand(0), V); 4349e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } 4359440db886627161a8413e823797569fc7b10beafChris Lattner Args.push_back(new LoadInst(V, V->getName()+".val", Call)); 4369e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.copyValue(OrigLoad, Args.back()); 4379440db886627161a8413e823797569fc7b10beafChris Lattner } 438ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 439ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 440ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (ExtraArgHack) 441c5b206b6be61d0d933b98b6af5e22f42edd48ad1Reid Spencer Args.push_back(Constant::getNullValue(Type::Int32Ty)); 442ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 443ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Push any varargs arguments on the list 444ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (; AI != CS.arg_end(); ++AI) 445ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args.push_back(*AI); 446ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 447ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Instruction *New; 448ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) { 449ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner New = new InvokeInst(NF, II->getNormalDest(), II->getUnwindDest(), 450f1355a55f8d815f5385e9a4432195f03b65f3a42David Greene Args.begin(), Args.end(), "", Call); 451f201dbc1a4a638659ec3916785196e2c204c7755Chris Lattner cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv()); 452ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } else { 45352eec548206d0b135b55ba52dd0e82e978f15ae5David Greene New = new CallInst(NF, Args.begin(), Args.end(), "", Call); 454f201dbc1a4a638659ec3916785196e2c204c7755Chris Lattner cast<CallInst>(New)->setCallingConv(CS.getCallingConv()); 4551430ef134d36888b99d2e6fedd2b025882593538Chris Lattner if (cast<CallInst>(Call)->isTailCall()) 4561430ef134d36888b99d2e6fedd2b025882593538Chris Lattner cast<CallInst>(New)->setTailCall(); 457ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 458ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args.clear(); 459ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 4609e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Update the alias analysis implementation to know that we are replacing 4619e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // the old call with a new one. 4629e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(Call, New); 4639e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 464ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!Call->use_empty()) { 465ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Call->replaceAllUsesWith(New); 466046800a7125cd497613efc0e1ea15cb595666585Chris Lattner New->takeName(Call); 467ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 468fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 469ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Finally, remove the old call from the program, reducing the use-count of 470ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // F. 471ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Call->getParent()->getInstList().erase(Call); 472ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 473ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 474ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Since we have now created the new function, splice the body of the old 475ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // function right into the new function, leaving the old rotting hulk of the 476ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // function empty. 477ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList()); 478ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 479ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Loop over the argument list, transfering uses of the old arguments over to 480ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // the new arguments, also transfering over the names as well. 481ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // 48293e985f1b17aef62d58e3198a4604f9f6cfe8d19Chris Lattner for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(), 48393e985f1b17aef62d58e3198a4604f9f6cfe8d19Chris Lattner I2 = NF->arg_begin(); I != E; ++I) 484ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!ArgsToPromote.count(I)) { 485ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // If this is an unmodified argument, move the name and users over to the 486ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // new version. 487ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner I->replaceAllUsesWith(I2); 488046800a7125cd497613efc0e1ea15cb595666585Chris Lattner I2->takeName(I); 4899e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(I, I2); 490ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner ++I2; 4919e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else if (I->use_empty()) { 4929e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.deleteValue(I); 4939e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else { 494ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Otherwise, if we promoted this argument, then all users are load 495ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // instructions, and all loads should be using the new argument that we 496ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // added. 497beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner ScalarizeTable &ArgIndices = ScalarizedElements[I]; 4989440db886627161a8413e823797569fc7b10beafChris Lattner 499ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner while (!I->use_empty()) { 5009440db886627161a8413e823797569fc7b10beafChris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(I->use_back())) { 5019440db886627161a8413e823797569fc7b10beafChris Lattner assert(ArgIndices.begin()->empty() && 5029440db886627161a8413e823797569fc7b10beafChris Lattner "Load element should sort to front!"); 5039440db886627161a8413e823797569fc7b10beafChris Lattner I2->setName(I->getName()+".val"); 5049440db886627161a8413e823797569fc7b10beafChris Lattner LI->replaceAllUsesWith(I2); 5059e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(LI, I2); 5069440db886627161a8413e823797569fc7b10beafChris Lattner LI->getParent()->getInstList().erase(LI); 5070a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling DOUT << "*** Promoted load of argument '" << I->getName() 5080a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling << "' in function '" << F->getName() << "'\n"; 5099440db886627161a8413e823797569fc7b10beafChris Lattner } else { 5109440db886627161a8413e823797569fc7b10beafChris Lattner GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->use_back()); 5119440db886627161a8413e823797569fc7b10beafChris Lattner std::vector<Value*> Operands(GEP->op_begin()+1, GEP->op_end()); 5129440db886627161a8413e823797569fc7b10beafChris Lattner 513e4d5c441e04bdc00ccf1804744af670655123b07Chris Lattner Function::arg_iterator TheArg = I2; 514beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (ScalarizeTable::iterator It = ArgIndices.begin(); 5159440db886627161a8413e823797569fc7b10beafChris Lattner *It != Operands; ++It, ++TheArg) { 5169440db886627161a8413e823797569fc7b10beafChris Lattner assert(It != ArgIndices.end() && "GEP not handled??"); 5179440db886627161a8413e823797569fc7b10beafChris Lattner } 5189440db886627161a8413e823797569fc7b10beafChris Lattner 5199440db886627161a8413e823797569fc7b10beafChris Lattner std::string NewName = I->getName(); 5209440db886627161a8413e823797569fc7b10beafChris Lattner for (unsigned i = 0, e = Operands.size(); i != e; ++i) 5219440db886627161a8413e823797569fc7b10beafChris Lattner if (ConstantInt *CI = dyn_cast<ConstantInt>(Operands[i])) 5229132a2b81842b0e2b77703fab3e6fe7467f859bbChris Lattner NewName += "." + CI->getValue().toStringUnsigned(10); 5239440db886627161a8413e823797569fc7b10beafChris Lattner else 5249440db886627161a8413e823797569fc7b10beafChris Lattner NewName += ".x"; 5259440db886627161a8413e823797569fc7b10beafChris Lattner TheArg->setName(NewName+".val"); 5269440db886627161a8413e823797569fc7b10beafChris Lattner 5270a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling DOUT << "*** Promoted agg argument '" << TheArg->getName() 5280a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling << "' of function '" << F->getName() << "'\n"; 5299440db886627161a8413e823797569fc7b10beafChris Lattner 5309440db886627161a8413e823797569fc7b10beafChris Lattner // All of the uses must be load instructions. Replace them all with 5319440db886627161a8413e823797569fc7b10beafChris Lattner // the argument specified by ArgNo. 5329440db886627161a8413e823797569fc7b10beafChris Lattner while (!GEP->use_empty()) { 5339440db886627161a8413e823797569fc7b10beafChris Lattner LoadInst *L = cast<LoadInst>(GEP->use_back()); 5349440db886627161a8413e823797569fc7b10beafChris Lattner L->replaceAllUsesWith(TheArg); 5359e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(L, TheArg); 5369440db886627161a8413e823797569fc7b10beafChris Lattner L->getParent()->getInstList().erase(L); 5379440db886627161a8413e823797569fc7b10beafChris Lattner } 5389e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.deleteValue(GEP); 5399440db886627161a8413e823797569fc7b10beafChris Lattner GEP->getParent()->getInstList().erase(GEP); 5409440db886627161a8413e823797569fc7b10beafChris Lattner } 541ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 54286a734bd40857db9ef205234f3b58e550ee5959bChris Lattner 5435eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Increment I2 past all of the arguments added for this promoted pointer. 5445eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner for (unsigned i = 0, e = ArgIndices.size(); i != e; ++i) 5455eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner ++I2; 546ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 547ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 5489e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Notify the alias analysis implementation that we inserted a new argument. 5499e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (ExtraArgHack) 550c5b206b6be61d0d933b98b6af5e22f42edd48ad1Reid Spencer AA.copyValue(Constant::getNullValue(Type::Int32Ty), NF->arg_begin()); 5519e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 5529e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 5539e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Tell the alias analysis that the old function is about to disappear. 5549e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(F, NF); 5559e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 556ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Now that the old function is dead, delete it. 557ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner F->getParent()->getFunctionList().erase(F); 5585eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner return NF; 559ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 560