ArgumentPromotion.cpp revision 194c90ed2a8e74b5a1c5184835f84c572d524dad
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" 38dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands#include "llvm/ParameterAttributes.h" 39ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Analysis/AliasAnalysis.h" 405eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner#include "llvm/Analysis/CallGraph.h" 41ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Target/TargetData.h" 42ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Support/CallSite.h" 43ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Support/CFG.h" 44551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/Debug.h" 45551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/DepthFirstIterator.h" 46551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/Statistic.h" 47551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/StringExtras.h" 489133fe28954d498fc4de13064c7d65bd811de02cReid Spencer#include "llvm/Support/Compiler.h" 49ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include <set> 50ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattnerusing namespace llvm; 51ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 5286453c52ba02e743d29c08456e51006500041456Chris LattnerSTATISTIC(NumArgumentsPromoted , "Number of pointer arguments promoted"); 5386453c52ba02e743d29c08456e51006500041456Chris LattnerSTATISTIC(NumAggregatesPromoted, "Number of aggregate arguments promoted"); 5486453c52ba02e743d29c08456e51006500041456Chris LattnerSTATISTIC(NumArgumentsDead , "Number of dead pointer args eliminated"); 55ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 5686453c52ba02e743d29c08456e51006500041456Chris Lattnernamespace { 57ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner /// ArgPromotion - The 'by reference' to 'by value' argument promotion pass. 58ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner /// 599133fe28954d498fc4de13064c7d65bd811de02cReid Spencer struct VISIBILITY_HIDDEN ArgPromotion : public CallGraphSCCPass { 60ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner virtual void getAnalysisUsage(AnalysisUsage &AU) const { 61ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner AU.addRequired<AliasAnalysis>(); 62ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner AU.addRequired<TargetData>(); 635eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner CallGraphSCCPass::getAnalysisUsage(AU); 64ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 65ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 665eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner virtual bool runOnSCC(const std::vector<CallGraphNode *> &SCC); 67ecd94c804a563f2a86572dcf1d2e81f397e19daaNick Lewycky static char ID; // Pass identification, replacement for typeid 68794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel ArgPromotion() : CallGraphSCCPass((intptr_t)&ID) {} 69794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel 70ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner private: 715eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner bool PromoteArguments(CallGraphNode *CGN); 72fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman bool isSafeToPromoteArgument(Argument *Arg) const; 735eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Function *DoPromotion(Function *F, std::vector<Argument*> &ArgsToPromote); 74ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner }; 75ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 761997473cf72957d0e70322e2fe6fe2ab141c58a6Devang Patel char ArgPromotion::ID = 0; 777f8897f22e88271cfa114998a4d6088e7c8e8e11Chris Lattner RegisterPass<ArgPromotion> X("argpromotion", 787f8897f22e88271cfa114998a4d6088e7c8e8e11Chris Lattner "Promote 'by reference' arguments to scalars"); 79ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 80ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 81c71ca3cdd2d7a08b043ebb717cad0beadaf47450Devang PatelPass *llvm::createArgumentPromotionPass() { 82ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return new ArgPromotion(); 83ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 84ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 855eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattnerbool ArgPromotion::runOnSCC(const std::vector<CallGraphNode *> &SCC) { 865eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner bool Changed = false, LocalChange; 87ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 88f5afcabff887c2e9023f0c69c44f1de15b5c4347Chris Lattner do { // Iterate until we stop promoting from this SCC. 895eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner LocalChange = false; 905eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Attempt to promote arguments from all functions in this SCC. 915eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner for (unsigned i = 0, e = SCC.size(); i != e; ++i) 925eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner LocalChange |= PromoteArguments(SCC[i]); 935eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Changed |= LocalChange; // Remember that we changed something. 945eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner } while (LocalChange); 95fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 96ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return Changed; 97ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 98ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 999e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// PromoteArguments - This method checks the specified function to see if there 1009e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// are any promotable arguments and if it is safe to promote the function (for 1019e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// example, all callers are direct). If safe to promote some arguments, it 1029e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// calls the DoPromotion method. 1039e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// 1045eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattnerbool ArgPromotion::PromoteArguments(CallGraphNode *CGN) { 1055eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Function *F = CGN->getFunction(); 1065eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner 1075eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Make sure that it is local to this module. 1085eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner if (!F || !F->hasInternalLinkage()) return false; 109ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 110ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // First check: see if there are any pointer arguments! If not, quick exit. 111ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<Argument*> PointerArgs; 112e4d5c441e04bdc00ccf1804744af670655123b07Chris Lattner for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I) 113ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (isa<PointerType>(I->getType())) 114ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner PointerArgs.push_back(I); 115ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (PointerArgs.empty()) return false; 116ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 117ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Second check: make sure that all callers are direct callers. We can't 118ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // transform functions that have indirect callers. 119ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (Value::use_iterator UI = F->use_begin(), E = F->use_end(); 1207db5a6df78749bf0cd37870fcefe08b8849e38e6Chris Lattner UI != E; ++UI) { 1217db5a6df78749bf0cd37870fcefe08b8849e38e6Chris Lattner CallSite CS = CallSite::get(*UI); 1229e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (!CS.getInstruction()) // "Taking the address" of the function 1239e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner return false; 1249e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 1259e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Ensure that this call site is CALLING the function, not passing it as 1269e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // an argument. 1279e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end(); 1289e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AI != E; ++AI) 1299e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (*AI == F) return false; // Passing the function address in! 1307db5a6df78749bf0cd37870fcefe08b8849e38e6Chris Lattner } 131ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 132ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Check to see which arguments are promotable. If an argument is not 133ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // promotable, remove it from the PointerArgs vector. 134ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (unsigned i = 0; i != PointerArgs.size(); ++i) 135ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!isSafeToPromoteArgument(PointerArgs[i])) { 136ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::swap(PointerArgs[i--], PointerArgs.back()); 137ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner PointerArgs.pop_back(); 138ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 139ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 140ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // No promotable pointer arguments. 141ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (PointerArgs.empty()) return false; 142ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 143dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands // Okay, promote all of the arguments and rewrite the callees! 1445eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Function *NewF = DoPromotion(F, PointerArgs); 1455eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner 146dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands // Update the call graph to know that the function has been transformed. 1475eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner getAnalysis<CallGraph>().changeFunction(F, NewF); 148ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return true; 149ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 150ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 15111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner/// IsAlwaysValidPointer - Return true if the specified pointer is always legal 15211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner/// to load. 15311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattnerstatic bool IsAlwaysValidPointer(Value *V) { 15411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner if (isa<AllocaInst>(V) || isa<GlobalVariable>(V)) return true; 15511a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V)) 15611a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return IsAlwaysValidPointer(GEP->getOperand(0)); 15711a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) 15811a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner if (CE->getOpcode() == Instruction::GetElementPtr) 15911a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return IsAlwaysValidPointer(CE->getOperand(0)); 16011a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 16111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return false; 16211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner} 16311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 16411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner/// AllCalleesPassInValidPointerForArgument - Return true if we can prove that 16511a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner/// all callees pass in a valid pointer for the specified function argument. 16611a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattnerstatic bool AllCalleesPassInValidPointerForArgument(Argument *Arg) { 16711a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner Function *Callee = Arg->getParent(); 16811a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 16993e985f1b17aef62d58e3198a4604f9f6cfe8d19Chris Lattner unsigned ArgNo = std::distance(Callee->arg_begin(), 17093e985f1b17aef62d58e3198a4604f9f6cfe8d19Chris Lattner Function::arg_iterator(Arg)); 17111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 17211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // Look at all call sites of the function. At this pointer we know we only 17311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // have direct callees. 17411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner for (Value::use_iterator UI = Callee->use_begin(), E = Callee->use_end(); 17511a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner UI != E; ++UI) { 17611a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner CallSite CS = CallSite::get(*UI); 17711a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner assert(CS.getInstruction() && "Should only have direct calls!"); 17811a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 17911a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner if (!IsAlwaysValidPointer(CS.getArgument(ArgNo))) 18011a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return false; 18111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner } 18211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return true; 18311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner} 18411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 1859e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 1869e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// isSafeToPromoteArgument - As you might guess from the name of this method, 1879e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// it checks to see if it is both safe and useful to promote the argument. 1889e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// This method limits promotion of aggregates to only promote up to three 1899e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// elements of the aggregate in order to avoid exploding the number of 1909e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// arguments passed in. 191ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattnerbool ArgPromotion::isSafeToPromoteArgument(Argument *Arg) const { 1929440db886627161a8413e823797569fc7b10beafChris Lattner // We can only promote this argument if all of the uses are loads, or are GEP 1939440db886627161a8413e823797569fc7b10beafChris Lattner // instructions (with constant indices) that are subsequently loaded. 19411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner bool HasLoadInEntryBlock = false; 19511a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner BasicBlock *EntryBlock = Arg->getParent()->begin(); 196ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<LoadInst*> Loads; 197beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner std::vector<std::vector<ConstantInt*> > GEPIndices; 198ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (Value::use_iterator UI = Arg->use_begin(), E = Arg->use_end(); 199ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner UI != E; ++UI) 200ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 201ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (LI->isVolatile()) return false; // Don't hack volatile loads 202ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Loads.push_back(LI); 20311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner HasLoadInEntryBlock |= LI->getParent() == EntryBlock; 2049440db886627161a8413e823797569fc7b10beafChris Lattner } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) { 2059440db886627161a8413e823797569fc7b10beafChris Lattner if (GEP->use_empty()) { 2069440db886627161a8413e823797569fc7b10beafChris Lattner // Dead GEP's cause trouble later. Just remove them if we run into 2079440db886627161a8413e823797569fc7b10beafChris Lattner // them. 2089e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner getAnalysis<AliasAnalysis>().deleteValue(GEP); 2099440db886627161a8413e823797569fc7b10beafChris Lattner GEP->getParent()->getInstList().erase(GEP); 2109440db886627161a8413e823797569fc7b10beafChris Lattner return isSafeToPromoteArgument(Arg); 2119440db886627161a8413e823797569fc7b10beafChris Lattner } 2129440db886627161a8413e823797569fc7b10beafChris Lattner // Ensure that all of the indices are constants. 213beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner std::vector<ConstantInt*> Operands; 2149440db886627161a8413e823797569fc7b10beafChris Lattner for (unsigned i = 1, e = GEP->getNumOperands(); i != e; ++i) 215beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner if (ConstantInt *C = dyn_cast<ConstantInt>(GEP->getOperand(i))) 2169440db886627161a8413e823797569fc7b10beafChris Lattner Operands.push_back(C); 2179440db886627161a8413e823797569fc7b10beafChris Lattner else 2189440db886627161a8413e823797569fc7b10beafChris Lattner return false; // Not a constant operand GEP! 2199440db886627161a8413e823797569fc7b10beafChris Lattner 2209440db886627161a8413e823797569fc7b10beafChris Lattner // Ensure that the only users of the GEP are load instructions. 2219440db886627161a8413e823797569fc7b10beafChris Lattner for (Value::use_iterator UI = GEP->use_begin(), E = GEP->use_end(); 2229440db886627161a8413e823797569fc7b10beafChris Lattner UI != E; ++UI) 2239440db886627161a8413e823797569fc7b10beafChris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 2249440db886627161a8413e823797569fc7b10beafChris Lattner if (LI->isVolatile()) return false; // Don't hack volatile loads 2259440db886627161a8413e823797569fc7b10beafChris Lattner Loads.push_back(LI); 22611a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner HasLoadInEntryBlock |= LI->getParent() == EntryBlock; 2279440db886627161a8413e823797569fc7b10beafChris Lattner } else { 2289440db886627161a8413e823797569fc7b10beafChris Lattner return false; 2299440db886627161a8413e823797569fc7b10beafChris Lattner } 230ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 2319e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // See if there is already a GEP with these indices. If not, check to 2329e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // make sure that we aren't promoting too many elements. If so, nothing 2339e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // to do. 2349440db886627161a8413e823797569fc7b10beafChris Lattner if (std::find(GEPIndices.begin(), GEPIndices.end(), Operands) == 2359440db886627161a8413e823797569fc7b10beafChris Lattner GEPIndices.end()) { 2369440db886627161a8413e823797569fc7b10beafChris Lattner if (GEPIndices.size() == 3) { 2370a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling DOUT << "argpromotion disable promoting argument '" 2380a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling << Arg->getName() << "' because it would require adding more " 2390a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling << "than 3 arguments to the function.\n"; 2409440db886627161a8413e823797569fc7b10beafChris Lattner // We limit aggregate promotion to only promoting up to three elements 2419440db886627161a8413e823797569fc7b10beafChris Lattner // of the aggregate. 2429440db886627161a8413e823797569fc7b10beafChris Lattner return false; 2439440db886627161a8413e823797569fc7b10beafChris Lattner } 2449440db886627161a8413e823797569fc7b10beafChris Lattner GEPIndices.push_back(Operands); 2459440db886627161a8413e823797569fc7b10beafChris Lattner } 2469440db886627161a8413e823797569fc7b10beafChris Lattner } else { 2479440db886627161a8413e823797569fc7b10beafChris Lattner return false; // Not a load or a GEP. 2489440db886627161a8413e823797569fc7b10beafChris Lattner } 249ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 2509e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (Loads.empty()) return true; // No users, this is a dead argument. 251ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 25211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // If we decide that we want to promote this argument, the value is going to 25311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // be unconditionally loaded in all callees. This is only safe to do if the 25411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // pointer was going to be unconditionally loaded anyway (i.e. there is a load 25511a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // of the pointer in the entry block of the function) or if we can prove that 25611a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // all pointers passed in are always to legal locations (for example, no null 25711a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // pointers are passed in, no pointers to free'd memory, etc). 25899435d32b3318f1b2f593f484ea9ba26804bf56cEvan Cheng if (!HasLoadInEntryBlock && !AllCalleesPassInValidPointerForArgument(Arg)) 25911a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner return false; // Cannot prove that this is safe!! 26011a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner 26111a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // Okay, now we know that the argument is only used by load instructions and 26211a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // it is safe to unconditionally load the pointer. Use alias analysis to 26311a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // check to see if the pointer is guaranteed to not be modified from entry of 26411a3d7b7ddd10659b72ed248d878fa0d90ddcb45Chris Lattner // the function to each of the load instructions. 265ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 266ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Because there could be several/many load instructions, remember which 267ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // blocks we know to be transparent to the load. 268ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::set<BasicBlock*> TranspBlocks; 26946f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson 27046f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 2719440db886627161a8413e823797569fc7b10beafChris Lattner TargetData &TD = getAnalysis<TargetData>(); 272ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 273ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (unsigned i = 0, e = Loads.size(); i != e; ++i) { 274ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Check to see if the load is invalidated from the start of the block to 275ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // the load itself. 276ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner LoadInst *Load = Loads[i]; 277ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner BasicBlock *BB = Load->getParent(); 2789440db886627161a8413e823797569fc7b10beafChris Lattner 2799440db886627161a8413e823797569fc7b10beafChris Lattner const PointerType *LoadTy = 2809440db886627161a8413e823797569fc7b10beafChris Lattner cast<PointerType>(Load->getOperand(0)->getType()); 281514ab348fddcdffa8367685dc608b2f8d5de986dDuncan Sands unsigned LoadSize = (unsigned)TD.getTypeStoreSize(LoadTy->getElementType()); 2829440db886627161a8413e823797569fc7b10beafChris Lattner 283ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (AA.canInstructionRangeModify(BB->front(), *Load, Arg, LoadSize)) 284ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return false; // Pointer is invalidated! 285ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 286ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Now check every path from the entry block to the load for transparency. 287ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // To do this, we perform a depth first search on the inverse CFG from the 288ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // loading block. 289ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) 290ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (idf_ext_iterator<BasicBlock*> I = idf_ext_begin(*PI, TranspBlocks), 291ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner E = idf_ext_end(*PI, TranspBlocks); I != E; ++I) 292ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (AA.canBasicBlockModify(**I, Arg, LoadSize)) 293ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return false; 294ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 295ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 296ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // If the path from the entry of the function to each load is free of 297ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // instructions that potentially invalidate the load, we can make the 298ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // transformation! 299ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return true; 300ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 301ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 302beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattnernamespace { 303beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner /// GEPIdxComparator - Provide a strong ordering for GEP indices. All Value* 304beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner /// elements are instances of ConstantInt. 305beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner /// 306beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner struct GEPIdxComparator { 307beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner bool operator()(const std::vector<Value*> &LHS, 308beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner const std::vector<Value*> &RHS) const { 309beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner unsigned idx = 0; 310beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (; idx < LHS.size() && idx < RHS.size(); ++idx) { 311beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner if (LHS[idx] != RHS[idx]) { 312b83eb6447ba155342598f0fabe1f08f5baa9164aReid Spencer return cast<ConstantInt>(LHS[idx])->getZExtValue() < 313b83eb6447ba155342598f0fabe1f08f5baa9164aReid Spencer cast<ConstantInt>(RHS[idx])->getZExtValue(); 314beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner } 315beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner } 316beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 317beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner // Return less than if we ran out of stuff in LHS and we didn't run out of 318beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner // stuff in RHS. 319beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner return idx == LHS.size() && idx != RHS.size(); 320beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner } 321beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner }; 322beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner} 323beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 324beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 3259e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// DoPromotion - This method actually performs the promotion of the specified 3265eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner/// arguments, and returns the new function. At this point, we know that it's 3275eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner/// safe to do so. 3285eb6f6c829ddfe353f94623aa1009c72be930497Chris LattnerFunction *ArgPromotion::DoPromotion(Function *F, 3295eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner std::vector<Argument*> &Args2Prom) { 330ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::set<Argument*> ArgsToPromote(Args2Prom.begin(), Args2Prom.end()); 331fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 332ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Start by computing a new prototype for the function, which is the same as 333ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // the old function, but has modified arguments. 334ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner const FunctionType *FTy = F->getFunctionType(); 335ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<const Type*> Params; 336ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 337beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner typedef std::set<std::vector<Value*>, GEPIdxComparator> ScalarizeTable; 338beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 3399440db886627161a8413e823797569fc7b10beafChris Lattner // ScalarizedElements - If we are promoting a pointer that has elements 3409440db886627161a8413e823797569fc7b10beafChris Lattner // accessed out of it, keep track of which elements are accessed so that we 3419440db886627161a8413e823797569fc7b10beafChris Lattner // can add one argument for each. 3429440db886627161a8413e823797569fc7b10beafChris Lattner // 3439440db886627161a8413e823797569fc7b10beafChris Lattner // Arguments that are directly loaded will have a zero element value here, to 3449440db886627161a8413e823797569fc7b10beafChris Lattner // handle cases where there are both a direct load and GEP accesses. 3459440db886627161a8413e823797569fc7b10beafChris Lattner // 346beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner std::map<Argument*, ScalarizeTable> ScalarizedElements; 3479440db886627161a8413e823797569fc7b10beafChris Lattner 3489e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // OriginalLoads - Keep track of a representative load instruction from the 3499e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // original function so that we can tell the alias analysis implementation 3509e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // what the new GEP/Load instructions we are inserting look like. 3519e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner std::map<std::vector<Value*>, LoadInst*> OriginalLoads; 3529e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 353dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands // ParamAttrs - Keep track of the parameter attributes for the arguments 354dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands // that we are *not* promoting. For the ones that we do promote, the parameter 355dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands // attributes are lost 356dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands ParamAttrsVector ParamAttrsVec; 357dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands const ParamAttrsList *PAL = F->getParamAttrs(); 358dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands 359dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands unsigned index = 1; 360dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; 361dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands ++I, ++index) 362ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!ArgsToPromote.count(I)) { 363ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Params.push_back(I->getType()); 364dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands if (PAL) { 365dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands unsigned attrs = PAL->getParamAttrs(index); 366dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands if (attrs) 367dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands ParamAttrsVec.push_back(ParamAttrsWithIndex::get(Params.size(), 368dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands attrs)); 369dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands } 3709e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else if (I->use_empty()) { 3719e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner ++NumArgumentsDead; 3729e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else { 3739440db886627161a8413e823797569fc7b10beafChris Lattner // Okay, this is being promoted. Check to see if there are any GEP uses 3749440db886627161a8413e823797569fc7b10beafChris Lattner // of the argument. 375beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner ScalarizeTable &ArgIndices = ScalarizedElements[I]; 3769440db886627161a8413e823797569fc7b10beafChris Lattner for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; 3779440db886627161a8413e823797569fc7b10beafChris Lattner ++UI) { 3789440db886627161a8413e823797569fc7b10beafChris Lattner Instruction *User = cast<Instruction>(*UI); 37946f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson assert(isa<LoadInst>(User) || isa<GetElementPtrInst>(User)); 38046f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson std::vector<Value*> Indices(User->op_begin()+1, User->op_end()); 38146f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson ArgIndices.insert(Indices); 38246f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson LoadInst *OrigLoad; 38346f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson if (LoadInst *L = dyn_cast<LoadInst>(User)) 38446f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson OrigLoad = L; 38546f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson else 38646f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson OrigLoad = cast<LoadInst>(User->use_back()); 38746f022a7f105211d5ea2c394e406d1943b80908cOwen Anderson OriginalLoads[Indices] = OrigLoad; 3889440db886627161a8413e823797569fc7b10beafChris Lattner } 3899440db886627161a8413e823797569fc7b10beafChris Lattner 3909440db886627161a8413e823797569fc7b10beafChris Lattner // Add a parameter to the function for each element passed in. 391beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (ScalarizeTable::iterator SI = ArgIndices.begin(), 3929440db886627161a8413e823797569fc7b10beafChris Lattner E = ArgIndices.end(); SI != E; ++SI) 3931ccd185cb49d81465a2901622e58ceae046d1d83Chris Lattner Params.push_back(GetElementPtrInst::getIndexedType(I->getType(), 394b8f74793b9d161bc666fe27fc92fe112b6ec169bDavid Greene SI->begin(), 395b8f74793b9d161bc666fe27fc92fe112b6ec169bDavid Greene SI->end())); 3969440db886627161a8413e823797569fc7b10beafChris Lattner 3979440db886627161a8413e823797569fc7b10beafChris Lattner if (ArgIndices.size() == 1 && ArgIndices.begin()->empty()) 3989440db886627161a8413e823797569fc7b10beafChris Lattner ++NumArgumentsPromoted; 3999440db886627161a8413e823797569fc7b10beafChris Lattner else 4009440db886627161a8413e823797569fc7b10beafChris Lattner ++NumAggregatesPromoted; 401ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 402ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 403ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner const Type *RetTy = FTy->getReturnType(); 404ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 405dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands // Recompute the parameter attributes list based on the new arguments for 406dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands // the function. 407dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands if (ParamAttrsVec.empty()) 408dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands PAL = 0; 409dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands else 410dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands PAL = ParamAttrsList::get(ParamAttrsVec); 411dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands 412ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Work around LLVM bug PR56: the CWriter cannot emit varargs functions which 413ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // have zero fixed arguments. 414ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner bool ExtraArgHack = false; 415ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (Params.empty() && FTy->isVarArg()) { 416ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner ExtraArgHack = true; 417c5b206b6be61d0d933b98b6af5e22f42edd48ad1Reid Spencer Params.push_back(Type::Int32Ty); 418ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 419dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands 420dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands // Construct the new function type using the new arguments. 421ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg()); 422fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 423dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands // Create the new function body and insert it into the module... 424ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Function *NF = new Function(NFTy, F->getLinkage(), F->getName()); 425f201dbc1a4a638659ec3916785196e2c204c7755Chris Lattner NF->setCallingConv(F->getCallingConv()); 426dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands NF->setParamAttrs(PAL); 427194c90ed2a8e74b5a1c5184835f84c572d524dadGordon Henriksen if (F->hasCollector()) 428194c90ed2a8e74b5a1c5184835f84c572d524dadGordon Henriksen NF->setCollector(F->getCollector()); 429ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner F->getParent()->getFunctionList().insert(F, NF); 4309e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 4319e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Get the alias analysis information that we need to update to reflect our 4329e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // changes. 4339e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 4349e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 435ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Loop over all of the callers of the function, transforming the call sites 436ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // to pass in the loaded pointers. 437ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // 438ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<Value*> Args; 439ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner while (!F->use_empty()) { 440ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner CallSite CS = CallSite::get(F->use_back()); 441ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Instruction *Call = CS.getInstruction(); 442ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 4439e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Loop over the operands, inserting GEP and loads in the caller as 4449e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // appropriate. 445ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner CallSite::arg_iterator AI = CS.arg_begin(); 446f201dbc1a4a638659ec3916785196e2c204c7755Chris Lattner for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); 447f201dbc1a4a638659ec3916785196e2c204c7755Chris Lattner I != E; ++I, ++AI) 448ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!ArgsToPromote.count(I)) 449ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args.push_back(*AI); // Unmodified argument 450ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner else if (!I->use_empty()) { 4519e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Non-dead argument: insert GEPs and loads as appropriate. 452beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner ScalarizeTable &ArgIndices = ScalarizedElements[I]; 453beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (ScalarizeTable::iterator SI = ArgIndices.begin(), 4549440db886627161a8413e823797569fc7b10beafChris Lattner E = ArgIndices.end(); SI != E; ++SI) { 4559440db886627161a8413e823797569fc7b10beafChris Lattner Value *V = *AI; 4569e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner LoadInst *OrigLoad = OriginalLoads[*SI]; 4579e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (!SI->empty()) { 458b8f74793b9d161bc666fe27fc92fe112b6ec169bDavid Greene V = new GetElementPtrInst(V, SI->begin(), SI->end(), 4591ccd185cb49d81465a2901622e58ceae046d1d83Chris Lattner V->getName()+".idx", Call); 4609e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.copyValue(OrigLoad->getOperand(0), V); 4619e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } 4629440db886627161a8413e823797569fc7b10beafChris Lattner Args.push_back(new LoadInst(V, V->getName()+".val", Call)); 4639e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.copyValue(OrigLoad, Args.back()); 4649440db886627161a8413e823797569fc7b10beafChris Lattner } 465ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 466ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 467ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (ExtraArgHack) 468c5b206b6be61d0d933b98b6af5e22f42edd48ad1Reid Spencer Args.push_back(Constant::getNullValue(Type::Int32Ty)); 469ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 470ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Push any varargs arguments on the list 471ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (; AI != CS.arg_end(); ++AI) 472ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args.push_back(*AI); 473ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 474ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Instruction *New; 475ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) { 476ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner New = new InvokeInst(NF, II->getNormalDest(), II->getUnwindDest(), 477f1355a55f8d815f5385e9a4432195f03b65f3a42David Greene Args.begin(), Args.end(), "", Call); 478f201dbc1a4a638659ec3916785196e2c204c7755Chris Lattner cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv()); 479dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands cast<InvokeInst>(New)->setParamAttrs(PAL); 480ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } else { 48152eec548206d0b135b55ba52dd0e82e978f15ae5David Greene New = new CallInst(NF, Args.begin(), Args.end(), "", Call); 482f201dbc1a4a638659ec3916785196e2c204c7755Chris Lattner cast<CallInst>(New)->setCallingConv(CS.getCallingConv()); 483dc024674ff96820d6020757b48d47f46d4c07db2Duncan Sands cast<CallInst>(New)->setParamAttrs(PAL); 4841430ef134d36888b99d2e6fedd2b025882593538Chris Lattner if (cast<CallInst>(Call)->isTailCall()) 4851430ef134d36888b99d2e6fedd2b025882593538Chris Lattner cast<CallInst>(New)->setTailCall(); 486ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 487ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args.clear(); 488ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 4899e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Update the alias analysis implementation to know that we are replacing 4909e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // the old call with a new one. 4919e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(Call, New); 4929e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 493ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!Call->use_empty()) { 494ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Call->replaceAllUsesWith(New); 495046800a7125cd497613efc0e1ea15cb595666585Chris Lattner New->takeName(Call); 496ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 497fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 498ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Finally, remove the old call from the program, reducing the use-count of 499ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // F. 500ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Call->getParent()->getInstList().erase(Call); 501ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 502ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 503ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Since we have now created the new function, splice the body of the old 504ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // function right into the new function, leaving the old rotting hulk of the 505ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // function empty. 506ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList()); 507ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 508ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Loop over the argument list, transfering uses of the old arguments over to 509ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // the new arguments, also transfering over the names as well. 510ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // 51193e985f1b17aef62d58e3198a4604f9f6cfe8d19Chris Lattner for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(), 51293e985f1b17aef62d58e3198a4604f9f6cfe8d19Chris Lattner I2 = NF->arg_begin(); I != E; ++I) 513ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!ArgsToPromote.count(I)) { 514ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // If this is an unmodified argument, move the name and users over to the 515ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // new version. 516ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner I->replaceAllUsesWith(I2); 517046800a7125cd497613efc0e1ea15cb595666585Chris Lattner I2->takeName(I); 5189e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(I, I2); 519ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner ++I2; 5209e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else if (I->use_empty()) { 5219e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.deleteValue(I); 5229e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else { 523ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Otherwise, if we promoted this argument, then all users are load 524ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // instructions, and all loads should be using the new argument that we 525ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // added. 526beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner ScalarizeTable &ArgIndices = ScalarizedElements[I]; 5279440db886627161a8413e823797569fc7b10beafChris Lattner 528ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner while (!I->use_empty()) { 5299440db886627161a8413e823797569fc7b10beafChris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(I->use_back())) { 5309440db886627161a8413e823797569fc7b10beafChris Lattner assert(ArgIndices.begin()->empty() && 5319440db886627161a8413e823797569fc7b10beafChris Lattner "Load element should sort to front!"); 5329440db886627161a8413e823797569fc7b10beafChris Lattner I2->setName(I->getName()+".val"); 5339440db886627161a8413e823797569fc7b10beafChris Lattner LI->replaceAllUsesWith(I2); 5349e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(LI, I2); 5359440db886627161a8413e823797569fc7b10beafChris Lattner LI->getParent()->getInstList().erase(LI); 5360a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling DOUT << "*** Promoted load of argument '" << I->getName() 5370a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling << "' in function '" << F->getName() << "'\n"; 5389440db886627161a8413e823797569fc7b10beafChris Lattner } else { 5399440db886627161a8413e823797569fc7b10beafChris Lattner GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->use_back()); 5409440db886627161a8413e823797569fc7b10beafChris Lattner std::vector<Value*> Operands(GEP->op_begin()+1, GEP->op_end()); 5419440db886627161a8413e823797569fc7b10beafChris Lattner 542e4d5c441e04bdc00ccf1804744af670655123b07Chris Lattner Function::arg_iterator TheArg = I2; 543beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (ScalarizeTable::iterator It = ArgIndices.begin(); 5449440db886627161a8413e823797569fc7b10beafChris Lattner *It != Operands; ++It, ++TheArg) { 5459440db886627161a8413e823797569fc7b10beafChris Lattner assert(It != ArgIndices.end() && "GEP not handled??"); 5469440db886627161a8413e823797569fc7b10beafChris Lattner } 5479440db886627161a8413e823797569fc7b10beafChris Lattner 5489440db886627161a8413e823797569fc7b10beafChris Lattner std::string NewName = I->getName(); 5499440db886627161a8413e823797569fc7b10beafChris Lattner for (unsigned i = 0, e = Operands.size(); i != e; ++i) 5509440db886627161a8413e823797569fc7b10beafChris Lattner if (ConstantInt *CI = dyn_cast<ConstantInt>(Operands[i])) 5519132a2b81842b0e2b77703fab3e6fe7467f859bbChris Lattner NewName += "." + CI->getValue().toStringUnsigned(10); 5529440db886627161a8413e823797569fc7b10beafChris Lattner else 5539440db886627161a8413e823797569fc7b10beafChris Lattner NewName += ".x"; 5549440db886627161a8413e823797569fc7b10beafChris Lattner TheArg->setName(NewName+".val"); 5559440db886627161a8413e823797569fc7b10beafChris Lattner 5560a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling DOUT << "*** Promoted agg argument '" << TheArg->getName() 5570a81aac4b46eed130d20714af5a1c01b05d0275eBill Wendling << "' of function '" << F->getName() << "'\n"; 5589440db886627161a8413e823797569fc7b10beafChris Lattner 5599440db886627161a8413e823797569fc7b10beafChris Lattner // All of the uses must be load instructions. Replace them all with 5609440db886627161a8413e823797569fc7b10beafChris Lattner // the argument specified by ArgNo. 5619440db886627161a8413e823797569fc7b10beafChris Lattner while (!GEP->use_empty()) { 5629440db886627161a8413e823797569fc7b10beafChris Lattner LoadInst *L = cast<LoadInst>(GEP->use_back()); 5639440db886627161a8413e823797569fc7b10beafChris Lattner L->replaceAllUsesWith(TheArg); 5649e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(L, TheArg); 5659440db886627161a8413e823797569fc7b10beafChris Lattner L->getParent()->getInstList().erase(L); 5669440db886627161a8413e823797569fc7b10beafChris Lattner } 5679e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.deleteValue(GEP); 5689440db886627161a8413e823797569fc7b10beafChris Lattner GEP->getParent()->getInstList().erase(GEP); 5699440db886627161a8413e823797569fc7b10beafChris Lattner } 570ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 57186a734bd40857db9ef205234f3b58e550ee5959bChris Lattner 5725eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Increment I2 past all of the arguments added for this promoted pointer. 5735eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner for (unsigned i = 0, e = ArgIndices.size(); i != e; ++i) 5745eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner ++I2; 575ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 576ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 5779e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Notify the alias analysis implementation that we inserted a new argument. 5789e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (ExtraArgHack) 579c5b206b6be61d0d933b98b6af5e22f42edd48ad1Reid Spencer AA.copyValue(Constant::getNullValue(Type::Int32Ty), NF->arg_begin()); 5809e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 5819e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 5829e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Tell the alias analysis that the old function is about to disappear. 5839e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(F, NF); 5849e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 585ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Now that the old function is dead, delete it. 586ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner F->getParent()->getFunctionList().erase(F); 5875eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner return NF; 588ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 589