Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 1 | //===- GlobalOpt.cpp - Optimize Global Variables --------------------------===// |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 2 | // |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
Chris Lattner | 4ee451d | 2007-12-29 20:36:04 +0000 | [diff] [blame^] | 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 7 | // |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 10 | // This pass transforms simple global variables that never have their address |
| 11 | // taken. If obviously true, it marks read/write globals as constant, deletes |
| 12 | // variables only stored to, etc. |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 13 | // |
| 14 | //===----------------------------------------------------------------------===// |
| 15 | |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 16 | #define DEBUG_TYPE "globalopt" |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 17 | #include "llvm/Transforms/IPO.h" |
Chris Lattner | fb217ad | 2005-05-08 22:18:06 +0000 | [diff] [blame] | 18 | #include "llvm/CallingConv.h" |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 19 | #include "llvm/Constants.h" |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 20 | #include "llvm/DerivedTypes.h" |
Chris Lattner | 7d90a27 | 2004-02-27 18:09:25 +0000 | [diff] [blame] | 21 | #include "llvm/Instructions.h" |
Chris Lattner | 35c81b0 | 2005-02-27 18:58:52 +0000 | [diff] [blame] | 22 | #include "llvm/IntrinsicInst.h" |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 23 | #include "llvm/Module.h" |
| 24 | #include "llvm/Pass.h" |
Chris Lattner | 79066fa | 2007-01-30 23:46:24 +0000 | [diff] [blame] | 25 | #include "llvm/Analysis/ConstantFolding.h" |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 26 | #include "llvm/Target/TargetData.h" |
Reid Spencer | 9133fe2 | 2007-02-05 23:32:05 +0000 | [diff] [blame] | 27 | #include "llvm/Support/Compiler.h" |
Chris Lattner | 79066fa | 2007-01-30 23:46:24 +0000 | [diff] [blame] | 28 | #include "llvm/Support/Debug.h" |
Chris Lattner | 8168618 | 2007-09-13 16:30:19 +0000 | [diff] [blame] | 29 | #include "llvm/ADT/SmallPtrSet.h" |
Chris Lattner | 55eb1c4 | 2007-01-31 04:40:53 +0000 | [diff] [blame] | 30 | #include "llvm/ADT/SmallVector.h" |
Reid Spencer | 551ccae | 2004-09-01 22:55:40 +0000 | [diff] [blame] | 31 | #include "llvm/ADT/Statistic.h" |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 32 | #include "llvm/ADT/StringExtras.h" |
Chris Lattner | e47ba74 | 2004-10-06 20:57:02 +0000 | [diff] [blame] | 33 | #include <algorithm> |
Chris Lattner | dac58ad | 2006-01-22 23:32:06 +0000 | [diff] [blame] | 34 | #include <set> |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 35 | using namespace llvm; |
| 36 | |
Chris Lattner | 86453c5 | 2006-12-19 22:09:18 +0000 | [diff] [blame] | 37 | STATISTIC(NumMarked , "Number of globals marked constant"); |
| 38 | STATISTIC(NumSRA , "Number of aggregate globals broken into scalars"); |
| 39 | STATISTIC(NumHeapSRA , "Number of heap objects SRA'd"); |
| 40 | STATISTIC(NumSubstitute,"Number of globals with initializers stored into them"); |
| 41 | STATISTIC(NumDeleted , "Number of globals deleted"); |
| 42 | STATISTIC(NumFnDeleted , "Number of functions deleted"); |
| 43 | STATISTIC(NumGlobUses , "Number of global uses devirtualized"); |
| 44 | STATISTIC(NumLocalized , "Number of globals localized"); |
| 45 | STATISTIC(NumShrunkToBool , "Number of global vars shrunk to booleans"); |
| 46 | STATISTIC(NumFastCallFns , "Number of functions converted to fastcc"); |
| 47 | STATISTIC(NumCtorsEvaluated, "Number of static ctors evaluated"); |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 48 | |
Chris Lattner | 86453c5 | 2006-12-19 22:09:18 +0000 | [diff] [blame] | 49 | namespace { |
Reid Spencer | 9133fe2 | 2007-02-05 23:32:05 +0000 | [diff] [blame] | 50 | struct VISIBILITY_HIDDEN GlobalOpt : public ModulePass { |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 51 | virtual void getAnalysisUsage(AnalysisUsage &AU) const { |
| 52 | AU.addRequired<TargetData>(); |
| 53 | } |
Nick Lewycky | ecd94c8 | 2007-05-06 13:37:16 +0000 | [diff] [blame] | 54 | static char ID; // Pass identification, replacement for typeid |
Devang Patel | 794fd75 | 2007-05-01 21:15:47 +0000 | [diff] [blame] | 55 | GlobalOpt() : ModulePass((intptr_t)&ID) {} |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 56 | |
Chris Lattner | b12914b | 2004-09-20 04:48:05 +0000 | [diff] [blame] | 57 | bool runOnModule(Module &M); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 58 | |
| 59 | private: |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 60 | GlobalVariable *FindGlobalCtors(Module &M); |
| 61 | bool OptimizeFunctions(Module &M); |
| 62 | bool OptimizeGlobalVars(Module &M); |
| 63 | bool OptimizeGlobalCtorsList(GlobalVariable *&GCL); |
Chris Lattner | 7f8897f | 2006-08-27 22:42:52 +0000 | [diff] [blame] | 64 | bool ProcessInternalGlobal(GlobalVariable *GV,Module::global_iterator &GVI); |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 65 | }; |
| 66 | |
Devang Patel | 1997473 | 2007-05-03 01:11:54 +0000 | [diff] [blame] | 67 | char GlobalOpt::ID = 0; |
Chris Lattner | 7f8897f | 2006-08-27 22:42:52 +0000 | [diff] [blame] | 68 | RegisterPass<GlobalOpt> X("globalopt", "Global Variable Optimizer"); |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 69 | } |
| 70 | |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 71 | ModulePass *llvm::createGlobalOptimizerPass() { return new GlobalOpt(); } |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 72 | |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 73 | /// GlobalStatus - As we analyze each global, keep track of some information |
| 74 | /// about it. If we find out that the address of the global is taken, none of |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 75 | /// this info will be accurate. |
Reid Spencer | 9133fe2 | 2007-02-05 23:32:05 +0000 | [diff] [blame] | 76 | struct VISIBILITY_HIDDEN GlobalStatus { |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 77 | /// isLoaded - True if the global is ever loaded. If the global isn't ever |
| 78 | /// loaded it can be deleted. |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 79 | bool isLoaded; |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 80 | |
| 81 | /// StoredType - Keep track of what stores to the global look like. |
| 82 | /// |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 83 | enum StoredType { |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 84 | /// NotStored - There is no store to this global. It can thus be marked |
| 85 | /// constant. |
| 86 | NotStored, |
| 87 | |
| 88 | /// isInitializerStored - This global is stored to, but the only thing |
| 89 | /// stored is the constant it was initialized with. This is only tracked |
| 90 | /// for scalar globals. |
| 91 | isInitializerStored, |
| 92 | |
| 93 | /// isStoredOnce - This global is stored to, but only its initializer and |
| 94 | /// one other value is ever stored to it. If this global isStoredOnce, we |
| 95 | /// track the value stored to it in StoredOnceValue below. This is only |
| 96 | /// tracked for scalar globals. |
| 97 | isStoredOnce, |
| 98 | |
| 99 | /// isStored - This global is stored to by multiple values or something else |
| 100 | /// that we cannot track. |
| 101 | isStored |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 102 | } StoredType; |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 103 | |
| 104 | /// StoredOnceValue - If only one value (besides the initializer constant) is |
| 105 | /// ever stored to this global, keep track of what value it is. |
| 106 | Value *StoredOnceValue; |
| 107 | |
Chris Lattner | 25de4e5 | 2006-11-01 18:03:33 +0000 | [diff] [blame] | 108 | /// AccessingFunction/HasMultipleAccessingFunctions - These start out |
| 109 | /// null/false. When the first accessing function is noticed, it is recorded. |
| 110 | /// When a second different accessing function is noticed, |
| 111 | /// HasMultipleAccessingFunctions is set to true. |
Alkis Evlogimenos | f64ea9d | 2005-02-10 18:36:30 +0000 | [diff] [blame] | 112 | Function *AccessingFunction; |
| 113 | bool HasMultipleAccessingFunctions; |
| 114 | |
Chris Lattner | 25de4e5 | 2006-11-01 18:03:33 +0000 | [diff] [blame] | 115 | /// HasNonInstructionUser - Set to true if this global has a user that is not |
| 116 | /// an instruction (e.g. a constant expr or GV initializer). |
Chris Lattner | 553ca52 | 2005-06-15 21:11:48 +0000 | [diff] [blame] | 117 | bool HasNonInstructionUser; |
| 118 | |
Chris Lattner | 25de4e5 | 2006-11-01 18:03:33 +0000 | [diff] [blame] | 119 | /// HasPHIUser - Set to true if this global has a user that is a PHI node. |
| 120 | bool HasPHIUser; |
| 121 | |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 122 | /// isNotSuitableForSRA - Keep track of whether any SRA preventing users of |
| 123 | /// the global exist. Such users include GEP instruction with variable |
| 124 | /// indexes, and non-gep/load/store users like constant expr casts. |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 125 | bool isNotSuitableForSRA; |
Chris Lattner | 9ce3000 | 2004-07-20 03:58:07 +0000 | [diff] [blame] | 126 | |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 127 | GlobalStatus() : isLoaded(false), StoredType(NotStored), StoredOnceValue(0), |
Alkis Evlogimenos | f64ea9d | 2005-02-10 18:36:30 +0000 | [diff] [blame] | 128 | AccessingFunction(0), HasMultipleAccessingFunctions(false), |
Chris Lattner | 25de4e5 | 2006-11-01 18:03:33 +0000 | [diff] [blame] | 129 | HasNonInstructionUser(false), HasPHIUser(false), |
| 130 | isNotSuitableForSRA(false) {} |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 131 | }; |
Chris Lattner | e47ba74 | 2004-10-06 20:57:02 +0000 | [diff] [blame] | 132 | |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 133 | |
| 134 | |
| 135 | /// ConstantIsDead - Return true if the specified constant is (transitively) |
| 136 | /// dead. The constant may be used by other constants (e.g. constant arrays and |
| 137 | /// constant exprs) as long as they are dead, but it cannot be used by anything |
| 138 | /// else. |
| 139 | static bool ConstantIsDead(Constant *C) { |
| 140 | if (isa<GlobalValue>(C)) return false; |
| 141 | |
| 142 | for (Value::use_iterator UI = C->use_begin(), E = C->use_end(); UI != E; ++UI) |
| 143 | if (Constant *CU = dyn_cast<Constant>(*UI)) { |
| 144 | if (!ConstantIsDead(CU)) return false; |
| 145 | } else |
| 146 | return false; |
| 147 | return true; |
| 148 | } |
| 149 | |
| 150 | |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 151 | /// AnalyzeGlobal - Look at all uses of the global and fill in the GlobalStatus |
| 152 | /// structure. If the global has its address taken, return true to indicate we |
| 153 | /// can't do anything with it. |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 154 | /// |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 155 | static bool AnalyzeGlobal(Value *V, GlobalStatus &GS, |
| 156 | std::set<PHINode*> &PHIUsers) { |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 157 | for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI) |
Chris Lattner | 96940cb | 2004-07-18 19:56:20 +0000 | [diff] [blame] | 158 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(*UI)) { |
Chris Lattner | 553ca52 | 2005-06-15 21:11:48 +0000 | [diff] [blame] | 159 | GS.HasNonInstructionUser = true; |
| 160 | |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 161 | if (AnalyzeGlobal(CE, GS, PHIUsers)) return true; |
| 162 | if (CE->getOpcode() != Instruction::GetElementPtr) |
| 163 | GS.isNotSuitableForSRA = true; |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 164 | else if (!GS.isNotSuitableForSRA) { |
| 165 | // Check to see if this ConstantExpr GEP is SRA'able. In particular, we |
| 166 | // don't like < 3 operand CE's, and we don't like non-constant integer |
| 167 | // indices. |
| 168 | if (CE->getNumOperands() < 3 || !CE->getOperand(1)->isNullValue()) |
| 169 | GS.isNotSuitableForSRA = true; |
| 170 | else { |
| 171 | for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i) |
| 172 | if (!isa<ConstantInt>(CE->getOperand(i))) { |
| 173 | GS.isNotSuitableForSRA = true; |
| 174 | break; |
| 175 | } |
| 176 | } |
| 177 | } |
| 178 | |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 179 | } else if (Instruction *I = dyn_cast<Instruction>(*UI)) { |
Alkis Evlogimenos | f64ea9d | 2005-02-10 18:36:30 +0000 | [diff] [blame] | 180 | if (!GS.HasMultipleAccessingFunctions) { |
| 181 | Function *F = I->getParent()->getParent(); |
| 182 | if (GS.AccessingFunction == 0) |
| 183 | GS.AccessingFunction = F; |
| 184 | else if (GS.AccessingFunction != F) |
| 185 | GS.HasMultipleAccessingFunctions = true; |
| 186 | } |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 187 | if (isa<LoadInst>(I)) { |
| 188 | GS.isLoaded = true; |
| 189 | } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) { |
Chris Lattner | 3602549 | 2004-10-07 06:01:25 +0000 | [diff] [blame] | 190 | // Don't allow a store OF the address, only stores TO the address. |
| 191 | if (SI->getOperand(0) == V) return true; |
| 192 | |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 193 | // If this is a direct store to the global (i.e., the global is a scalar |
| 194 | // value, not an aggregate), keep more specific information about |
| 195 | // stores. |
| 196 | if (GS.StoredType != GlobalStatus::isStored) |
| 197 | if (GlobalVariable *GV = dyn_cast<GlobalVariable>(SI->getOperand(1))){ |
Chris Lattner | bd38edf | 2004-11-14 20:50:30 +0000 | [diff] [blame] | 198 | Value *StoredVal = SI->getOperand(0); |
| 199 | if (StoredVal == GV->getInitializer()) { |
| 200 | if (GS.StoredType < GlobalStatus::isInitializerStored) |
| 201 | GS.StoredType = GlobalStatus::isInitializerStored; |
| 202 | } else if (isa<LoadInst>(StoredVal) && |
| 203 | cast<LoadInst>(StoredVal)->getOperand(0) == GV) { |
| 204 | // G = G |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 205 | if (GS.StoredType < GlobalStatus::isInitializerStored) |
| 206 | GS.StoredType = GlobalStatus::isInitializerStored; |
| 207 | } else if (GS.StoredType < GlobalStatus::isStoredOnce) { |
| 208 | GS.StoredType = GlobalStatus::isStoredOnce; |
Chris Lattner | bd38edf | 2004-11-14 20:50:30 +0000 | [diff] [blame] | 209 | GS.StoredOnceValue = StoredVal; |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 210 | } else if (GS.StoredType == GlobalStatus::isStoredOnce && |
Chris Lattner | bd38edf | 2004-11-14 20:50:30 +0000 | [diff] [blame] | 211 | GS.StoredOnceValue == StoredVal) { |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 212 | // noop. |
| 213 | } else { |
| 214 | GS.StoredType = GlobalStatus::isStored; |
| 215 | } |
| 216 | } else { |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 217 | GS.StoredType = GlobalStatus::isStored; |
Chris Lattner | cf4d2a5 | 2004-10-07 21:30:30 +0000 | [diff] [blame] | 218 | } |
Chris Lattner | 35c81b0 | 2005-02-27 18:58:52 +0000 | [diff] [blame] | 219 | } else if (isa<GetElementPtrInst>(I)) { |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 220 | if (AnalyzeGlobal(I, GS, PHIUsers)) return true; |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 221 | |
| 222 | // If the first two indices are constants, this can be SRA'd. |
| 223 | if (isa<GlobalVariable>(I->getOperand(0))) { |
| 224 | if (I->getNumOperands() < 3 || !isa<Constant>(I->getOperand(1)) || |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 225 | !cast<Constant>(I->getOperand(1))->isNullValue() || |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 226 | !isa<ConstantInt>(I->getOperand(2))) |
| 227 | GS.isNotSuitableForSRA = true; |
| 228 | } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(I->getOperand(0))){ |
| 229 | if (CE->getOpcode() != Instruction::GetElementPtr || |
| 230 | CE->getNumOperands() < 3 || I->getNumOperands() < 2 || |
| 231 | !isa<Constant>(I->getOperand(0)) || |
| 232 | !cast<Constant>(I->getOperand(0))->isNullValue()) |
| 233 | GS.isNotSuitableForSRA = true; |
| 234 | } else { |
| 235 | GS.isNotSuitableForSRA = true; |
| 236 | } |
Chris Lattner | 35c81b0 | 2005-02-27 18:58:52 +0000 | [diff] [blame] | 237 | } else if (isa<SelectInst>(I)) { |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 238 | if (AnalyzeGlobal(I, GS, PHIUsers)) return true; |
| 239 | GS.isNotSuitableForSRA = true; |
| 240 | } else if (PHINode *PN = dyn_cast<PHINode>(I)) { |
| 241 | // PHI nodes we can check just like select or GEP instructions, but we |
| 242 | // have to be careful about infinite recursion. |
| 243 | if (PHIUsers.insert(PN).second) // Not already visited. |
| 244 | if (AnalyzeGlobal(I, GS, PHIUsers)) return true; |
| 245 | GS.isNotSuitableForSRA = true; |
Chris Lattner | 25de4e5 | 2006-11-01 18:03:33 +0000 | [diff] [blame] | 246 | GS.HasPHIUser = true; |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 247 | } else if (isa<CmpInst>(I)) { |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 248 | GS.isNotSuitableForSRA = true; |
Chris Lattner | 35c81b0 | 2005-02-27 18:58:52 +0000 | [diff] [blame] | 249 | } else if (isa<MemCpyInst>(I) || isa<MemMoveInst>(I)) { |
| 250 | if (I->getOperand(1) == V) |
| 251 | GS.StoredType = GlobalStatus::isStored; |
| 252 | if (I->getOperand(2) == V) |
| 253 | GS.isLoaded = true; |
| 254 | GS.isNotSuitableForSRA = true; |
| 255 | } else if (isa<MemSetInst>(I)) { |
| 256 | assert(I->getOperand(1) == V && "Memset only takes one pointer!"); |
| 257 | GS.StoredType = GlobalStatus::isStored; |
| 258 | GS.isNotSuitableForSRA = true; |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 259 | } else { |
| 260 | return true; // Any other non-load instruction might take address! |
Chris Lattner | 9ce3000 | 2004-07-20 03:58:07 +0000 | [diff] [blame] | 261 | } |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 262 | } else if (Constant *C = dyn_cast<Constant>(*UI)) { |
Chris Lattner | 553ca52 | 2005-06-15 21:11:48 +0000 | [diff] [blame] | 263 | GS.HasNonInstructionUser = true; |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 264 | // We might have a dead and dangling constant hanging off of here. |
| 265 | if (!ConstantIsDead(C)) |
| 266 | return true; |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 267 | } else { |
Chris Lattner | 553ca52 | 2005-06-15 21:11:48 +0000 | [diff] [blame] | 268 | GS.HasNonInstructionUser = true; |
| 269 | // Otherwise must be some other user. |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 270 | return true; |
| 271 | } |
| 272 | |
| 273 | return false; |
| 274 | } |
| 275 | |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 276 | static Constant *getAggregateConstantElement(Constant *Agg, Constant *Idx) { |
| 277 | ConstantInt *CI = dyn_cast<ConstantInt>(Idx); |
| 278 | if (!CI) return 0; |
Reid Spencer | b83eb64 | 2006-10-20 07:07:24 +0000 | [diff] [blame] | 279 | unsigned IdxV = CI->getZExtValue(); |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 280 | |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 281 | if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Agg)) { |
| 282 | if (IdxV < CS->getNumOperands()) return CS->getOperand(IdxV); |
| 283 | } else if (ConstantArray *CA = dyn_cast<ConstantArray>(Agg)) { |
| 284 | if (IdxV < CA->getNumOperands()) return CA->getOperand(IdxV); |
Reid Spencer | 9d6565a | 2007-02-15 02:26:10 +0000 | [diff] [blame] | 285 | } else if (ConstantVector *CP = dyn_cast<ConstantVector>(Agg)) { |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 286 | if (IdxV < CP->getNumOperands()) return CP->getOperand(IdxV); |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 287 | } else if (isa<ConstantAggregateZero>(Agg)) { |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 288 | if (const StructType *STy = dyn_cast<StructType>(Agg->getType())) { |
| 289 | if (IdxV < STy->getNumElements()) |
| 290 | return Constant::getNullValue(STy->getElementType(IdxV)); |
| 291 | } else if (const SequentialType *STy = |
| 292 | dyn_cast<SequentialType>(Agg->getType())) { |
| 293 | return Constant::getNullValue(STy->getElementType()); |
| 294 | } |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 295 | } else if (isa<UndefValue>(Agg)) { |
| 296 | if (const StructType *STy = dyn_cast<StructType>(Agg->getType())) { |
| 297 | if (IdxV < STy->getNumElements()) |
| 298 | return UndefValue::get(STy->getElementType(IdxV)); |
| 299 | } else if (const SequentialType *STy = |
| 300 | dyn_cast<SequentialType>(Agg->getType())) { |
| 301 | return UndefValue::get(STy->getElementType()); |
| 302 | } |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 303 | } |
| 304 | return 0; |
| 305 | } |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 306 | |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 307 | |
Chris Lattner | e47ba74 | 2004-10-06 20:57:02 +0000 | [diff] [blame] | 308 | /// CleanupConstantGlobalUsers - We just marked GV constant. Loop over all |
| 309 | /// users of the global, cleaning up the obvious ones. This is largely just a |
Chris Lattner | 031955d | 2004-10-10 16:43:46 +0000 | [diff] [blame] | 310 | /// quick scan over the use list to clean up the easy and obvious cruft. This |
| 311 | /// returns true if it made a change. |
| 312 | static bool CleanupConstantGlobalUsers(Value *V, Constant *Init) { |
| 313 | bool Changed = false; |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 314 | for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;) { |
| 315 | User *U = *UI++; |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 316 | |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 317 | if (LoadInst *LI = dyn_cast<LoadInst>(U)) { |
Chris Lattner | 35c81b0 | 2005-02-27 18:58:52 +0000 | [diff] [blame] | 318 | if (Init) { |
| 319 | // Replace the load with the initializer. |
| 320 | LI->replaceAllUsesWith(Init); |
| 321 | LI->eraseFromParent(); |
| 322 | Changed = true; |
| 323 | } |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 324 | } else if (StoreInst *SI = dyn_cast<StoreInst>(U)) { |
Chris Lattner | e47ba74 | 2004-10-06 20:57:02 +0000 | [diff] [blame] | 325 | // Store must be unreachable or storing Init into the global. |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 326 | SI->eraseFromParent(); |
Chris Lattner | 031955d | 2004-10-10 16:43:46 +0000 | [diff] [blame] | 327 | Changed = true; |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 328 | } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U)) { |
| 329 | if (CE->getOpcode() == Instruction::GetElementPtr) { |
Chris Lattner | aae4a1c | 2005-09-26 07:34:35 +0000 | [diff] [blame] | 330 | Constant *SubInit = 0; |
| 331 | if (Init) |
| 332 | SubInit = ConstantFoldLoadThroughGEPConstantExpr(Init, CE); |
Chris Lattner | 35c81b0 | 2005-02-27 18:58:52 +0000 | [diff] [blame] | 333 | Changed |= CleanupConstantGlobalUsers(CE, SubInit); |
Reid Spencer | 3da59db | 2006-11-27 01:05:10 +0000 | [diff] [blame] | 334 | } else if (CE->getOpcode() == Instruction::BitCast && |
Chris Lattner | 35c81b0 | 2005-02-27 18:58:52 +0000 | [diff] [blame] | 335 | isa<PointerType>(CE->getType())) { |
| 336 | // Pointer cast, delete any stores and memsets to the global. |
| 337 | Changed |= CleanupConstantGlobalUsers(CE, 0); |
| 338 | } |
| 339 | |
| 340 | if (CE->use_empty()) { |
| 341 | CE->destroyConstant(); |
| 342 | Changed = true; |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 343 | } |
| 344 | } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) { |
Chris Lattner | 7b52fe7 | 2007-11-09 17:33:02 +0000 | [diff] [blame] | 345 | // Do not transform "gepinst (gep constexpr (GV))" here, because forming |
| 346 | // "gepconstexpr (gep constexpr (GV))" will cause the two gep's to fold |
| 347 | // and will invalidate our notion of what Init is. |
Chris Lattner | 1945024 | 2007-11-13 21:46:23 +0000 | [diff] [blame] | 348 | Constant *SubInit = 0; |
Chris Lattner | 7b52fe7 | 2007-11-09 17:33:02 +0000 | [diff] [blame] | 349 | if (!isa<ConstantExpr>(GEP->getOperand(0))) { |
| 350 | ConstantExpr *CE = |
| 351 | dyn_cast_or_null<ConstantExpr>(ConstantFoldInstruction(GEP)); |
| 352 | if (Init && CE && CE->getOpcode() == Instruction::GetElementPtr) |
Chris Lattner | 1945024 | 2007-11-13 21:46:23 +0000 | [diff] [blame] | 353 | SubInit = ConstantFoldLoadThroughGEPConstantExpr(Init, CE); |
Chris Lattner | 7b52fe7 | 2007-11-09 17:33:02 +0000 | [diff] [blame] | 354 | } |
Chris Lattner | 1945024 | 2007-11-13 21:46:23 +0000 | [diff] [blame] | 355 | Changed |= CleanupConstantGlobalUsers(GEP, SubInit); |
Chris Lattner | c4d81b0 | 2004-10-10 16:47:33 +0000 | [diff] [blame] | 356 | |
Chris Lattner | 031955d | 2004-10-10 16:43:46 +0000 | [diff] [blame] | 357 | if (GEP->use_empty()) { |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 358 | GEP->eraseFromParent(); |
Chris Lattner | 031955d | 2004-10-10 16:43:46 +0000 | [diff] [blame] | 359 | Changed = true; |
| 360 | } |
Chris Lattner | 35c81b0 | 2005-02-27 18:58:52 +0000 | [diff] [blame] | 361 | } else if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(U)) { // memset/cpy/mv |
| 362 | if (MI->getRawDest() == V) { |
| 363 | MI->eraseFromParent(); |
| 364 | Changed = true; |
| 365 | } |
| 366 | |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 367 | } else if (Constant *C = dyn_cast<Constant>(U)) { |
| 368 | // If we have a chain of dead constantexprs or other things dangling from |
| 369 | // us, and if they are all dead, nuke them without remorse. |
| 370 | if (ConstantIsDead(C)) { |
| 371 | C->destroyConstant(); |
Chris Lattner | 35c81b0 | 2005-02-27 18:58:52 +0000 | [diff] [blame] | 372 | // This could have invalidated UI, start over from scratch. |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 373 | CleanupConstantGlobalUsers(V, Init); |
Chris Lattner | 031955d | 2004-10-10 16:43:46 +0000 | [diff] [blame] | 374 | return true; |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 375 | } |
Chris Lattner | e47ba74 | 2004-10-06 20:57:02 +0000 | [diff] [blame] | 376 | } |
| 377 | } |
Chris Lattner | 031955d | 2004-10-10 16:43:46 +0000 | [diff] [blame] | 378 | return Changed; |
Chris Lattner | e47ba74 | 2004-10-06 20:57:02 +0000 | [diff] [blame] | 379 | } |
| 380 | |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 381 | /// SRAGlobal - Perform scalar replacement of aggregates on the specified global |
| 382 | /// variable. This opens the door for other optimizations by exposing the |
| 383 | /// behavior of the program in a more fine-grained way. We have determined that |
| 384 | /// this transformation is safe already. We return the first global variable we |
| 385 | /// insert so that the caller can reprocess it. |
| 386 | static GlobalVariable *SRAGlobal(GlobalVariable *GV) { |
| 387 | assert(GV->hasInternalLinkage() && !GV->isConstant()); |
| 388 | Constant *Init = GV->getInitializer(); |
| 389 | const Type *Ty = Init->getType(); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 390 | |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 391 | std::vector<GlobalVariable*> NewGlobals; |
| 392 | Module::GlobalListType &Globals = GV->getParent()->getGlobalList(); |
| 393 | |
| 394 | if (const StructType *STy = dyn_cast<StructType>(Ty)) { |
| 395 | NewGlobals.reserve(STy->getNumElements()); |
| 396 | for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { |
| 397 | Constant *In = getAggregateConstantElement(Init, |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 398 | ConstantInt::get(Type::Int32Ty, i)); |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 399 | assert(In && "Couldn't get element of initializer?"); |
| 400 | GlobalVariable *NGV = new GlobalVariable(STy->getElementType(i), false, |
| 401 | GlobalVariable::InternalLinkage, |
Lauro Ramos Venancio | c763552 | 2007-04-12 18:32:50 +0000 | [diff] [blame] | 402 | In, GV->getName()+"."+utostr(i), |
| 403 | (Module *)NULL, |
| 404 | GV->isThreadLocal()); |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 405 | Globals.insert(GV, NGV); |
| 406 | NewGlobals.push_back(NGV); |
| 407 | } |
| 408 | } else if (const SequentialType *STy = dyn_cast<SequentialType>(Ty)) { |
| 409 | unsigned NumElements = 0; |
| 410 | if (const ArrayType *ATy = dyn_cast<ArrayType>(STy)) |
| 411 | NumElements = ATy->getNumElements(); |
Reid Spencer | 9d6565a | 2007-02-15 02:26:10 +0000 | [diff] [blame] | 412 | else if (const VectorType *PTy = dyn_cast<VectorType>(STy)) |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 413 | NumElements = PTy->getNumElements(); |
| 414 | else |
| 415 | assert(0 && "Unknown aggregate sequential type!"); |
| 416 | |
Chris Lattner | 1f21ef1 | 2005-02-23 16:53:04 +0000 | [diff] [blame] | 417 | if (NumElements > 16 && GV->hasNUsesOrMore(16)) |
Chris Lattner | d514d82 | 2005-02-01 01:23:31 +0000 | [diff] [blame] | 418 | return 0; // It's not worth it. |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 419 | NewGlobals.reserve(NumElements); |
| 420 | for (unsigned i = 0, e = NumElements; i != e; ++i) { |
| 421 | Constant *In = getAggregateConstantElement(Init, |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 422 | ConstantInt::get(Type::Int32Ty, i)); |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 423 | assert(In && "Couldn't get element of initializer?"); |
| 424 | |
| 425 | GlobalVariable *NGV = new GlobalVariable(STy->getElementType(), false, |
| 426 | GlobalVariable::InternalLinkage, |
Lauro Ramos Venancio | c763552 | 2007-04-12 18:32:50 +0000 | [diff] [blame] | 427 | In, GV->getName()+"."+utostr(i), |
| 428 | (Module *)NULL, |
| 429 | GV->isThreadLocal()); |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 430 | Globals.insert(GV, NGV); |
| 431 | NewGlobals.push_back(NGV); |
| 432 | } |
| 433 | } |
| 434 | |
| 435 | if (NewGlobals.empty()) |
| 436 | return 0; |
| 437 | |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 438 | DOUT << "PERFORMING GLOBAL SRA ON: " << *GV; |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 439 | |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 440 | Constant *NullInt = Constant::getNullValue(Type::Int32Ty); |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 441 | |
| 442 | // Loop over all of the uses of the global, replacing the constantexpr geps, |
| 443 | // with smaller constantexpr geps or direct references. |
| 444 | while (!GV->use_empty()) { |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 445 | User *GEP = GV->use_back(); |
| 446 | assert(((isa<ConstantExpr>(GEP) && |
| 447 | cast<ConstantExpr>(GEP)->getOpcode()==Instruction::GetElementPtr)|| |
| 448 | isa<GetElementPtrInst>(GEP)) && "NonGEP CE's are not SRAable!"); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 449 | |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 450 | // Ignore the 1th operand, which has to be zero or else the program is quite |
| 451 | // broken (undefined). Get the 2nd operand, which is the structure or array |
| 452 | // index. |
Reid Spencer | b83eb64 | 2006-10-20 07:07:24 +0000 | [diff] [blame] | 453 | unsigned Val = cast<ConstantInt>(GEP->getOperand(2))->getZExtValue(); |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 454 | if (Val >= NewGlobals.size()) Val = 0; // Out of bound array access. |
| 455 | |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 456 | Value *NewPtr = NewGlobals[Val]; |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 457 | |
| 458 | // Form a shorter GEP if needed. |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 459 | if (GEP->getNumOperands() > 3) |
| 460 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(GEP)) { |
Chris Lattner | 55eb1c4 | 2007-01-31 04:40:53 +0000 | [diff] [blame] | 461 | SmallVector<Constant*, 8> Idxs; |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 462 | Idxs.push_back(NullInt); |
| 463 | for (unsigned i = 3, e = CE->getNumOperands(); i != e; ++i) |
| 464 | Idxs.push_back(CE->getOperand(i)); |
Chris Lattner | 55eb1c4 | 2007-01-31 04:40:53 +0000 | [diff] [blame] | 465 | NewPtr = ConstantExpr::getGetElementPtr(cast<Constant>(NewPtr), |
| 466 | &Idxs[0], Idxs.size()); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 467 | } else { |
| 468 | GetElementPtrInst *GEPI = cast<GetElementPtrInst>(GEP); |
Chris Lattner | 699d144 | 2007-01-31 19:59:55 +0000 | [diff] [blame] | 469 | SmallVector<Value*, 8> Idxs; |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 470 | Idxs.push_back(NullInt); |
| 471 | for (unsigned i = 3, e = GEPI->getNumOperands(); i != e; ++i) |
| 472 | Idxs.push_back(GEPI->getOperand(i)); |
David Greene | b8f7479 | 2007-09-04 15:46:09 +0000 | [diff] [blame] | 473 | NewPtr = new GetElementPtrInst(NewPtr, Idxs.begin(), Idxs.end(), |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 474 | GEPI->getName()+"."+utostr(Val), GEPI); |
| 475 | } |
| 476 | GEP->replaceAllUsesWith(NewPtr); |
| 477 | |
| 478 | if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(GEP)) |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 479 | GEPI->eraseFromParent(); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 480 | else |
| 481 | cast<ConstantExpr>(GEP)->destroyConstant(); |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 482 | } |
| 483 | |
Chris Lattner | e40e2d1 | 2004-10-08 20:25:55 +0000 | [diff] [blame] | 484 | // Delete the old global, now that it is dead. |
| 485 | Globals.erase(GV); |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 486 | ++NumSRA; |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 487 | |
| 488 | // Loop over the new globals array deleting any globals that are obviously |
| 489 | // dead. This can arise due to scalarization of a structure or an array that |
| 490 | // has elements that are dead. |
| 491 | unsigned FirstGlobal = 0; |
| 492 | for (unsigned i = 0, e = NewGlobals.size(); i != e; ++i) |
| 493 | if (NewGlobals[i]->use_empty()) { |
| 494 | Globals.erase(NewGlobals[i]); |
| 495 | if (FirstGlobal == i) ++FirstGlobal; |
| 496 | } |
| 497 | |
| 498 | return FirstGlobal != NewGlobals.size() ? NewGlobals[FirstGlobal] : 0; |
Chris Lattner | 670c889 | 2004-10-08 17:32:09 +0000 | [diff] [blame] | 499 | } |
| 500 | |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 501 | /// AllUsesOfValueWillTrapIfNull - Return true if all users of the specified |
Chris Lattner | 8168618 | 2007-09-13 16:30:19 +0000 | [diff] [blame] | 502 | /// value will trap if the value is dynamically null. PHIs keeps track of any |
| 503 | /// phi nodes we've seen to avoid reprocessing them. |
| 504 | static bool AllUsesOfValueWillTrapIfNull(Value *V, |
| 505 | SmallPtrSet<PHINode*, 8> &PHIs) { |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 506 | for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI) |
| 507 | if (isa<LoadInst>(*UI)) { |
| 508 | // Will trap. |
| 509 | } else if (StoreInst *SI = dyn_cast<StoreInst>(*UI)) { |
| 510 | if (SI->getOperand(0) == V) { |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 511 | //cerr << "NONTRAPPING USE: " << **UI; |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 512 | return false; // Storing the value. |
| 513 | } |
| 514 | } else if (CallInst *CI = dyn_cast<CallInst>(*UI)) { |
| 515 | if (CI->getOperand(0) != V) { |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 516 | //cerr << "NONTRAPPING USE: " << **UI; |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 517 | return false; // Not calling the ptr |
| 518 | } |
| 519 | } else if (InvokeInst *II = dyn_cast<InvokeInst>(*UI)) { |
| 520 | if (II->getOperand(0) != V) { |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 521 | //cerr << "NONTRAPPING USE: " << **UI; |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 522 | return false; // Not calling the ptr |
| 523 | } |
Chris Lattner | 8168618 | 2007-09-13 16:30:19 +0000 | [diff] [blame] | 524 | } else if (BitCastInst *CI = dyn_cast<BitCastInst>(*UI)) { |
| 525 | if (!AllUsesOfValueWillTrapIfNull(CI, PHIs)) return false; |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 526 | } else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI)) { |
Chris Lattner | 8168618 | 2007-09-13 16:30:19 +0000 | [diff] [blame] | 527 | if (!AllUsesOfValueWillTrapIfNull(GEPI, PHIs)) return false; |
| 528 | } else if (PHINode *PN = dyn_cast<PHINode>(*UI)) { |
| 529 | // If we've already seen this phi node, ignore it, it has already been |
| 530 | // checked. |
| 531 | if (PHIs.insert(PN)) |
| 532 | return AllUsesOfValueWillTrapIfNull(PN, PHIs); |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 533 | } else if (isa<ICmpInst>(*UI) && |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 534 | isa<ConstantPointerNull>(UI->getOperand(1))) { |
| 535 | // Ignore setcc X, null |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 536 | } else { |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 537 | //cerr << "NONTRAPPING USE: " << **UI; |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 538 | return false; |
| 539 | } |
| 540 | return true; |
| 541 | } |
| 542 | |
| 543 | /// AllUsesOfLoadedValueWillTrapIfNull - Return true if all uses of any loads |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 544 | /// from GV will trap if the loaded value is null. Note that this also permits |
| 545 | /// comparisons of the loaded value against null, as a special case. |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 546 | static bool AllUsesOfLoadedValueWillTrapIfNull(GlobalVariable *GV) { |
| 547 | for (Value::use_iterator UI = GV->use_begin(), E = GV->use_end(); UI!=E; ++UI) |
| 548 | if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { |
Chris Lattner | 8168618 | 2007-09-13 16:30:19 +0000 | [diff] [blame] | 549 | SmallPtrSet<PHINode*, 8> PHIs; |
| 550 | if (!AllUsesOfValueWillTrapIfNull(LI, PHIs)) |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 551 | return false; |
| 552 | } else if (isa<StoreInst>(*UI)) { |
| 553 | // Ignore stores to the global. |
| 554 | } else { |
| 555 | // We don't know or understand this user, bail out. |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 556 | //cerr << "UNKNOWN USER OF GLOBAL!: " << **UI; |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 557 | return false; |
| 558 | } |
| 559 | |
| 560 | return true; |
| 561 | } |
| 562 | |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 563 | static bool OptimizeAwayTrappingUsesOfValue(Value *V, Constant *NewV) { |
| 564 | bool Changed = false; |
| 565 | for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ) { |
| 566 | Instruction *I = cast<Instruction>(*UI++); |
| 567 | if (LoadInst *LI = dyn_cast<LoadInst>(I)) { |
| 568 | LI->setOperand(0, NewV); |
| 569 | Changed = true; |
| 570 | } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) { |
| 571 | if (SI->getOperand(1) == V) { |
| 572 | SI->setOperand(1, NewV); |
| 573 | Changed = true; |
| 574 | } |
| 575 | } else if (isa<CallInst>(I) || isa<InvokeInst>(I)) { |
| 576 | if (I->getOperand(0) == V) { |
| 577 | // Calling through the pointer! Turn into a direct call, but be careful |
| 578 | // that the pointer is not also being passed as an argument. |
| 579 | I->setOperand(0, NewV); |
| 580 | Changed = true; |
| 581 | bool PassedAsArg = false; |
| 582 | for (unsigned i = 1, e = I->getNumOperands(); i != e; ++i) |
| 583 | if (I->getOperand(i) == V) { |
| 584 | PassedAsArg = true; |
| 585 | I->setOperand(i, NewV); |
| 586 | } |
| 587 | |
| 588 | if (PassedAsArg) { |
| 589 | // Being passed as an argument also. Be careful to not invalidate UI! |
| 590 | UI = V->use_begin(); |
| 591 | } |
| 592 | } |
| 593 | } else if (CastInst *CI = dyn_cast<CastInst>(I)) { |
| 594 | Changed |= OptimizeAwayTrappingUsesOfValue(CI, |
Chris Lattner | 6e8fbad | 2006-11-30 17:32:29 +0000 | [diff] [blame] | 595 | ConstantExpr::getCast(CI->getOpcode(), |
| 596 | NewV, CI->getType())); |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 597 | if (CI->use_empty()) { |
| 598 | Changed = true; |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 599 | CI->eraseFromParent(); |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 600 | } |
| 601 | } else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) { |
| 602 | // Should handle GEP here. |
Chris Lattner | 55eb1c4 | 2007-01-31 04:40:53 +0000 | [diff] [blame] | 603 | SmallVector<Constant*, 8> Idxs; |
| 604 | Idxs.reserve(GEPI->getNumOperands()-1); |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 605 | for (unsigned i = 1, e = GEPI->getNumOperands(); i != e; ++i) |
| 606 | if (Constant *C = dyn_cast<Constant>(GEPI->getOperand(i))) |
Chris Lattner | 55eb1c4 | 2007-01-31 04:40:53 +0000 | [diff] [blame] | 607 | Idxs.push_back(C); |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 608 | else |
| 609 | break; |
Chris Lattner | 55eb1c4 | 2007-01-31 04:40:53 +0000 | [diff] [blame] | 610 | if (Idxs.size() == GEPI->getNumOperands()-1) |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 611 | Changed |= OptimizeAwayTrappingUsesOfValue(GEPI, |
Chris Lattner | 55eb1c4 | 2007-01-31 04:40:53 +0000 | [diff] [blame] | 612 | ConstantExpr::getGetElementPtr(NewV, &Idxs[0], |
| 613 | Idxs.size())); |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 614 | if (GEPI->use_empty()) { |
| 615 | Changed = true; |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 616 | GEPI->eraseFromParent(); |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 617 | } |
| 618 | } |
| 619 | } |
| 620 | |
| 621 | return Changed; |
| 622 | } |
| 623 | |
| 624 | |
| 625 | /// OptimizeAwayTrappingUsesOfLoads - The specified global has only one non-null |
| 626 | /// value stored into it. If there are uses of the loaded value that would trap |
| 627 | /// if the loaded value is dynamically null, then we know that they cannot be |
| 628 | /// reachable with a null optimize away the load. |
| 629 | static bool OptimizeAwayTrappingUsesOfLoads(GlobalVariable *GV, Constant *LV) { |
| 630 | std::vector<LoadInst*> Loads; |
| 631 | bool Changed = false; |
| 632 | |
| 633 | // Replace all uses of loads with uses of uses of the stored value. |
| 634 | for (Value::use_iterator GUI = GV->use_begin(), E = GV->use_end(); |
| 635 | GUI != E; ++GUI) |
| 636 | if (LoadInst *LI = dyn_cast<LoadInst>(*GUI)) { |
| 637 | Loads.push_back(LI); |
| 638 | Changed |= OptimizeAwayTrappingUsesOfValue(LI, LV); |
| 639 | } else { |
Chris Lattner | ce3e2bf | 2007-05-15 06:42:04 +0000 | [diff] [blame] | 640 | // If we get here we could have stores, selects, or phi nodes whose values |
Chris Lattner | 79cfddf | 2007-05-13 21:28:07 +0000 | [diff] [blame] | 641 | // are loaded. |
Chris Lattner | ce3e2bf | 2007-05-15 06:42:04 +0000 | [diff] [blame] | 642 | assert((isa<StoreInst>(*GUI) || isa<PHINode>(*GUI) || |
| 643 | isa<SelectInst>(*GUI)) && |
Chris Lattner | 79cfddf | 2007-05-13 21:28:07 +0000 | [diff] [blame] | 644 | "Only expect load and stores!"); |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 645 | } |
| 646 | |
| 647 | if (Changed) { |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 648 | DOUT << "OPTIMIZED LOADS FROM STORED ONCE POINTER: " << *GV; |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 649 | ++NumGlobUses; |
| 650 | } |
| 651 | |
| 652 | // Delete all of the loads we can, keeping track of whether we nuked them all! |
| 653 | bool AllLoadsGone = true; |
| 654 | while (!Loads.empty()) { |
| 655 | LoadInst *L = Loads.back(); |
| 656 | if (L->use_empty()) { |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 657 | L->eraseFromParent(); |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 658 | Changed = true; |
| 659 | } else { |
| 660 | AllLoadsGone = false; |
| 661 | } |
| 662 | Loads.pop_back(); |
| 663 | } |
| 664 | |
| 665 | // If we nuked all of the loads, then none of the stores are needed either, |
| 666 | // nor is the global. |
| 667 | if (AllLoadsGone) { |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 668 | DOUT << " *** GLOBAL NOW DEAD!\n"; |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 669 | CleanupConstantGlobalUsers(GV, 0); |
| 670 | if (GV->use_empty()) { |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 671 | GV->eraseFromParent(); |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 672 | ++NumDeleted; |
| 673 | } |
| 674 | Changed = true; |
| 675 | } |
| 676 | return Changed; |
| 677 | } |
| 678 | |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 679 | /// ConstantPropUsersOf - Walk the use list of V, constant folding all of the |
| 680 | /// instructions that are foldable. |
| 681 | static void ConstantPropUsersOf(Value *V) { |
| 682 | for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ) |
| 683 | if (Instruction *I = dyn_cast<Instruction>(*UI++)) |
| 684 | if (Constant *NewC = ConstantFoldInstruction(I)) { |
| 685 | I->replaceAllUsesWith(NewC); |
| 686 | |
Chris Lattner | d514d82 | 2005-02-01 01:23:31 +0000 | [diff] [blame] | 687 | // Advance UI to the next non-I use to avoid invalidating it! |
| 688 | // Instructions could multiply use V. |
| 689 | while (UI != E && *UI == I) |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 690 | ++UI; |
Chris Lattner | d514d82 | 2005-02-01 01:23:31 +0000 | [diff] [blame] | 691 | I->eraseFromParent(); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 692 | } |
| 693 | } |
| 694 | |
| 695 | /// OptimizeGlobalAddressOfMalloc - This function takes the specified global |
| 696 | /// variable, and transforms the program as if it always contained the result of |
| 697 | /// the specified malloc. Because it is always the result of the specified |
| 698 | /// malloc, there is no reason to actually DO the malloc. Instead, turn the |
Chris Lattner | 6e8fbad | 2006-11-30 17:32:29 +0000 | [diff] [blame] | 699 | /// malloc into a global, and any loads of GV as uses of the new global. |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 700 | static GlobalVariable *OptimizeGlobalAddressOfMalloc(GlobalVariable *GV, |
| 701 | MallocInst *MI) { |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 702 | DOUT << "PROMOTING MALLOC GLOBAL: " << *GV << " MALLOC = " << *MI; |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 703 | ConstantInt *NElements = cast<ConstantInt>(MI->getArraySize()); |
| 704 | |
Reid Spencer | b83eb64 | 2006-10-20 07:07:24 +0000 | [diff] [blame] | 705 | if (NElements->getZExtValue() != 1) { |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 706 | // If we have an array allocation, transform it to a single element |
| 707 | // allocation to make the code below simpler. |
| 708 | Type *NewTy = ArrayType::get(MI->getAllocatedType(), |
Reid Spencer | b83eb64 | 2006-10-20 07:07:24 +0000 | [diff] [blame] | 709 | NElements->getZExtValue()); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 710 | MallocInst *NewMI = |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 711 | new MallocInst(NewTy, Constant::getNullValue(Type::Int32Ty), |
Nate Begeman | 14b0529 | 2005-11-05 09:21:28 +0000 | [diff] [blame] | 712 | MI->getAlignment(), MI->getName(), MI); |
Chris Lattner | 699d144 | 2007-01-31 19:59:55 +0000 | [diff] [blame] | 713 | Value* Indices[2]; |
| 714 | Indices[0] = Indices[1] = Constant::getNullValue(Type::Int32Ty); |
David Greene | b8f7479 | 2007-09-04 15:46:09 +0000 | [diff] [blame] | 715 | Value *NewGEP = new GetElementPtrInst(NewMI, Indices, Indices + 2, |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 716 | NewMI->getName()+".el0", MI); |
| 717 | MI->replaceAllUsesWith(NewGEP); |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 718 | MI->eraseFromParent(); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 719 | MI = NewMI; |
| 720 | } |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 721 | |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 722 | // Create the new global variable. The contents of the malloc'd memory is |
| 723 | // undefined, so initialize with an undef value. |
| 724 | Constant *Init = UndefValue::get(MI->getAllocatedType()); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 725 | GlobalVariable *NewGV = new GlobalVariable(MI->getAllocatedType(), false, |
| 726 | GlobalValue::InternalLinkage, Init, |
Lauro Ramos Venancio | c763552 | 2007-04-12 18:32:50 +0000 | [diff] [blame] | 727 | GV->getName()+".body", |
| 728 | (Module *)NULL, |
| 729 | GV->isThreadLocal()); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 730 | GV->getParent()->getGlobalList().insert(GV, NewGV); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 731 | |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 732 | // Anything that used the malloc now uses the global directly. |
| 733 | MI->replaceAllUsesWith(NewGV); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 734 | |
| 735 | Constant *RepValue = NewGV; |
| 736 | if (NewGV->getType() != GV->getType()->getElementType()) |
Reid Spencer | d977d86 | 2006-12-12 23:36:14 +0000 | [diff] [blame] | 737 | RepValue = ConstantExpr::getBitCast(RepValue, |
| 738 | GV->getType()->getElementType()); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 739 | |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 740 | // If there is a comparison against null, we will insert a global bool to |
| 741 | // keep track of whether the global was initialized yet or not. |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 742 | GlobalVariable *InitBool = |
Reid Spencer | 4fe16d6 | 2007-01-11 18:21:29 +0000 | [diff] [blame] | 743 | new GlobalVariable(Type::Int1Ty, false, GlobalValue::InternalLinkage, |
Lauro Ramos Venancio | c763552 | 2007-04-12 18:32:50 +0000 | [diff] [blame] | 744 | ConstantInt::getFalse(), GV->getName()+".init", |
| 745 | (Module *)NULL, GV->isThreadLocal()); |
Chris Lattner | bc965b9 | 2004-12-02 06:25:58 +0000 | [diff] [blame] | 746 | bool InitBoolUsed = false; |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 747 | |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 748 | // Loop over all uses of GV, processing them in turn. |
Chris Lattner | bc965b9 | 2004-12-02 06:25:58 +0000 | [diff] [blame] | 749 | std::vector<StoreInst*> Stores; |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 750 | while (!GV->use_empty()) |
| 751 | if (LoadInst *LI = dyn_cast<LoadInst>(GV->use_back())) { |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 752 | while (!LI->use_empty()) { |
Chris Lattner | d514d82 | 2005-02-01 01:23:31 +0000 | [diff] [blame] | 753 | Use &LoadUse = LI->use_begin().getUse(); |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 754 | if (!isa<ICmpInst>(LoadUse.getUser())) |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 755 | LoadUse = RepValue; |
| 756 | else { |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 757 | ICmpInst *CI = cast<ICmpInst>(LoadUse.getUser()); |
| 758 | // Replace the cmp X, 0 with a use of the bool value. |
| 759 | Value *LV = new LoadInst(InitBool, InitBool->getName()+".val", CI); |
Chris Lattner | bc965b9 | 2004-12-02 06:25:58 +0000 | [diff] [blame] | 760 | InitBoolUsed = true; |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 761 | switch (CI->getPredicate()) { |
| 762 | default: assert(0 && "Unknown ICmp Predicate!"); |
| 763 | case ICmpInst::ICMP_ULT: |
| 764 | case ICmpInst::ICMP_SLT: |
Zhou Sheng | 6b6b6ef | 2007-01-11 12:24:14 +0000 | [diff] [blame] | 765 | LV = ConstantInt::getFalse(); // X < null -> always false |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 766 | break; |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 767 | case ICmpInst::ICMP_ULE: |
| 768 | case ICmpInst::ICMP_SLE: |
| 769 | case ICmpInst::ICMP_EQ: |
| 770 | LV = BinaryOperator::createNot(LV, "notinit", CI); |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 771 | break; |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 772 | case ICmpInst::ICMP_NE: |
| 773 | case ICmpInst::ICMP_UGE: |
| 774 | case ICmpInst::ICMP_SGE: |
| 775 | case ICmpInst::ICMP_UGT: |
| 776 | case ICmpInst::ICMP_SGT: |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 777 | break; // no change. |
| 778 | } |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 779 | CI->replaceAllUsesWith(LV); |
| 780 | CI->eraseFromParent(); |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 781 | } |
| 782 | } |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 783 | LI->eraseFromParent(); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 784 | } else { |
| 785 | StoreInst *SI = cast<StoreInst>(GV->use_back()); |
Chris Lattner | bc965b9 | 2004-12-02 06:25:58 +0000 | [diff] [blame] | 786 | // The global is initialized when the store to it occurs. |
Zhou Sheng | 6b6b6ef | 2007-01-11 12:24:14 +0000 | [diff] [blame] | 787 | new StoreInst(ConstantInt::getTrue(), InitBool, SI); |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 788 | SI->eraseFromParent(); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 789 | } |
| 790 | |
Chris Lattner | bc965b9 | 2004-12-02 06:25:58 +0000 | [diff] [blame] | 791 | // If the initialization boolean was used, insert it, otherwise delete it. |
| 792 | if (!InitBoolUsed) { |
| 793 | while (!InitBool->use_empty()) // Delete initializations |
| 794 | cast<Instruction>(InitBool->use_back())->eraseFromParent(); |
| 795 | delete InitBool; |
| 796 | } else |
| 797 | GV->getParent()->getGlobalList().insert(GV, InitBool); |
| 798 | |
| 799 | |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 800 | // Now the GV is dead, nuke it and the malloc. |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 801 | GV->eraseFromParent(); |
Chris Lattner | e9ece2a | 2004-10-22 06:43:28 +0000 | [diff] [blame] | 802 | MI->eraseFromParent(); |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 803 | |
| 804 | // To further other optimizations, loop over all users of NewGV and try to |
| 805 | // constant prop them. This will promote GEP instructions with constant |
| 806 | // indices into GEP constant-exprs, which will allow global-opt to hack on it. |
| 807 | ConstantPropUsersOf(NewGV); |
| 808 | if (RepValue != NewGV) |
| 809 | ConstantPropUsersOf(RepValue); |
| 810 | |
| 811 | return NewGV; |
| 812 | } |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 813 | |
Chris Lattner | fa07e4f | 2004-12-02 07:11:07 +0000 | [diff] [blame] | 814 | /// ValueIsOnlyUsedLocallyOrStoredToOneGlobal - Scan the use-list of V checking |
| 815 | /// to make sure that there are no complex uses of V. We permit simple things |
| 816 | /// like dereferencing the pointer, but not storing through the address, unless |
| 817 | /// it is to the specified global. |
| 818 | static bool ValueIsOnlyUsedLocallyOrStoredToOneGlobal(Instruction *V, |
Chris Lattner | c451f9c | 2007-09-13 16:37:20 +0000 | [diff] [blame] | 819 | GlobalVariable *GV, |
| 820 | SmallPtrSet<PHINode*, 8> &PHIs) { |
Chris Lattner | 5e6e494 | 2007-09-14 03:41:21 +0000 | [diff] [blame] | 821 | for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI) |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 822 | if (isa<LoadInst>(*UI) || isa<CmpInst>(*UI)) { |
Chris Lattner | fa07e4f | 2004-12-02 07:11:07 +0000 | [diff] [blame] | 823 | // Fine, ignore. |
| 824 | } else if (StoreInst *SI = dyn_cast<StoreInst>(*UI)) { |
| 825 | if (SI->getOperand(0) == V && SI->getOperand(1) != GV) |
| 826 | return false; // Storing the pointer itself... bad. |
| 827 | // Otherwise, storing through it, or storing into GV... fine. |
Chris Lattner | 5e6e494 | 2007-09-14 03:41:21 +0000 | [diff] [blame] | 828 | } else if (isa<GetElementPtrInst>(*UI)) { |
Chris Lattner | c451f9c | 2007-09-13 16:37:20 +0000 | [diff] [blame] | 829 | if (!ValueIsOnlyUsedLocallyOrStoredToOneGlobal(cast<Instruction>(*UI), |
| 830 | GV, PHIs)) |
Chris Lattner | fa07e4f | 2004-12-02 07:11:07 +0000 | [diff] [blame] | 831 | return false; |
Chris Lattner | c451f9c | 2007-09-13 16:37:20 +0000 | [diff] [blame] | 832 | } else if (PHINode *PN = dyn_cast<PHINode>(*UI)) { |
| 833 | // PHIs are ok if all uses are ok. Don't infinitely recurse through PHI |
| 834 | // cycles. |
| 835 | if (PHIs.insert(PN)) |
Chris Lattner | 5e6e494 | 2007-09-14 03:41:21 +0000 | [diff] [blame] | 836 | if (!ValueIsOnlyUsedLocallyOrStoredToOneGlobal(PN, GV, PHIs)) |
| 837 | return false; |
Chris Lattner | fa07e4f | 2004-12-02 07:11:07 +0000 | [diff] [blame] | 838 | } else { |
| 839 | return false; |
| 840 | } |
| 841 | return true; |
Chris Lattner | fa07e4f | 2004-12-02 07:11:07 +0000 | [diff] [blame] | 842 | } |
| 843 | |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 844 | /// ReplaceUsesOfMallocWithGlobal - The Alloc pointer is stored into GV |
| 845 | /// somewhere. Transform all uses of the allocation into loads from the |
| 846 | /// global and uses of the resultant pointer. Further, delete the store into |
| 847 | /// GV. This assumes that these value pass the |
| 848 | /// 'ValueIsOnlyUsedLocallyOrStoredToOneGlobal' predicate. |
| 849 | static void ReplaceUsesOfMallocWithGlobal(Instruction *Alloc, |
| 850 | GlobalVariable *GV) { |
| 851 | while (!Alloc->use_empty()) { |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 852 | Instruction *U = cast<Instruction>(*Alloc->use_begin()); |
| 853 | Instruction *InsertPt = U; |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 854 | if (StoreInst *SI = dyn_cast<StoreInst>(U)) { |
| 855 | // If this is the store of the allocation into the global, remove it. |
| 856 | if (SI->getOperand(1) == GV) { |
| 857 | SI->eraseFromParent(); |
| 858 | continue; |
| 859 | } |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 860 | } else if (PHINode *PN = dyn_cast<PHINode>(U)) { |
| 861 | // Insert the load in the corresponding predecessor, not right before the |
| 862 | // PHI. |
| 863 | unsigned PredNo = Alloc->use_begin().getOperandNo()/2; |
| 864 | InsertPt = PN->getIncomingBlock(PredNo)->getTerminator(); |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 865 | } |
| 866 | |
| 867 | // Insert a load from the global, and use it instead of the malloc. |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 868 | Value *NL = new LoadInst(GV, GV->getName()+".val", InsertPt); |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 869 | U->replaceUsesOfWith(Alloc, NL); |
| 870 | } |
| 871 | } |
| 872 | |
| 873 | /// GlobalLoadUsesSimpleEnoughForHeapSRA - If all users of values loaded from |
| 874 | /// GV are simple enough to perform HeapSRA, return true. |
Chris Lattner | 309f20f | 2007-09-13 21:31:36 +0000 | [diff] [blame] | 875 | static bool GlobalLoadUsesSimpleEnoughForHeapSRA(GlobalVariable *GV, |
| 876 | MallocInst *MI) { |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 877 | for (Value::use_iterator UI = GV->use_begin(), E = GV->use_end(); UI != E; |
| 878 | ++UI) |
| 879 | if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { |
| 880 | // We permit two users of the load: setcc comparing against the null |
| 881 | // pointer, and a getelementptr of a specific form. |
| 882 | for (Value::use_iterator UI = LI->use_begin(), E = LI->use_end(); UI != E; |
| 883 | ++UI) { |
| 884 | // Comparison against null is ok. |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 885 | if (ICmpInst *ICI = dyn_cast<ICmpInst>(*UI)) { |
| 886 | if (!isa<ConstantPointerNull>(ICI->getOperand(1))) |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 887 | return false; |
| 888 | continue; |
| 889 | } |
| 890 | |
| 891 | // getelementptr is also ok, but only a simple form. |
Chris Lattner | 309f20f | 2007-09-13 21:31:36 +0000 | [diff] [blame] | 892 | if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI)) { |
| 893 | // Must index into the array and into the struct. |
| 894 | if (GEPI->getNumOperands() < 3) |
| 895 | return false; |
| 896 | |
| 897 | // Otherwise the GEP is ok. |
| 898 | continue; |
| 899 | } |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 900 | |
Chris Lattner | 309f20f | 2007-09-13 21:31:36 +0000 | [diff] [blame] | 901 | if (PHINode *PN = dyn_cast<PHINode>(*UI)) { |
| 902 | // We have a phi of a load from the global. We can only handle this |
| 903 | // if the other PHI'd values are actually the same. In this case, |
| 904 | // the rewriter will just drop the phi entirely. |
| 905 | for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { |
| 906 | Value *IV = PN->getIncomingValue(i); |
| 907 | if (IV == LI) continue; // Trivial the same. |
| 908 | |
| 909 | // If the phi'd value is from the malloc that initializes the value, |
| 910 | // we can xform it. |
| 911 | if (IV == MI) continue; |
| 912 | |
| 913 | // Otherwise, we don't know what it is. |
| 914 | return false; |
| 915 | } |
| 916 | return true; |
| 917 | } |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 918 | |
Chris Lattner | 309f20f | 2007-09-13 21:31:36 +0000 | [diff] [blame] | 919 | // Otherwise we don't know what this is, not ok. |
| 920 | return false; |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 921 | } |
| 922 | } |
| 923 | return true; |
| 924 | } |
| 925 | |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 926 | /// GetHeapSROALoad - Return the load for the specified field of the HeapSROA'd |
| 927 | /// value, lazily creating it on demand. |
Chris Lattner | 309f20f | 2007-09-13 21:31:36 +0000 | [diff] [blame] | 928 | static Value *GetHeapSROALoad(Instruction *Load, unsigned FieldNo, |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 929 | const std::vector<GlobalVariable*> &FieldGlobals, |
| 930 | std::vector<Value *> &InsertedLoadsForPtr) { |
| 931 | if (InsertedLoadsForPtr.size() <= FieldNo) |
| 932 | InsertedLoadsForPtr.resize(FieldNo+1); |
| 933 | if (InsertedLoadsForPtr[FieldNo] == 0) |
| 934 | InsertedLoadsForPtr[FieldNo] = new LoadInst(FieldGlobals[FieldNo], |
| 935 | Load->getName()+".f" + |
| 936 | utostr(FieldNo), Load); |
| 937 | return InsertedLoadsForPtr[FieldNo]; |
| 938 | } |
| 939 | |
Chris Lattner | 330245e | 2007-09-13 17:29:05 +0000 | [diff] [blame] | 940 | /// RewriteHeapSROALoadUser - Given a load instruction and a value derived from |
| 941 | /// the load, rewrite the derived value to use the HeapSRoA'd load. |
| 942 | static void RewriteHeapSROALoadUser(LoadInst *Load, Instruction *LoadUser, |
| 943 | const std::vector<GlobalVariable*> &FieldGlobals, |
| 944 | std::vector<Value *> &InsertedLoadsForPtr) { |
| 945 | // If this is a comparison against null, handle it. |
| 946 | if (ICmpInst *SCI = dyn_cast<ICmpInst>(LoadUser)) { |
| 947 | assert(isa<ConstantPointerNull>(SCI->getOperand(1))); |
| 948 | // If we have a setcc of the loaded pointer, we can use a setcc of any |
| 949 | // field. |
| 950 | Value *NPtr; |
| 951 | if (InsertedLoadsForPtr.empty()) { |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 952 | NPtr = GetHeapSROALoad(Load, 0, FieldGlobals, InsertedLoadsForPtr); |
Chris Lattner | 330245e | 2007-09-13 17:29:05 +0000 | [diff] [blame] | 953 | } else { |
| 954 | NPtr = InsertedLoadsForPtr.back(); |
| 955 | } |
| 956 | |
| 957 | Value *New = new ICmpInst(SCI->getPredicate(), NPtr, |
| 958 | Constant::getNullValue(NPtr->getType()), |
| 959 | SCI->getName(), SCI); |
| 960 | SCI->replaceAllUsesWith(New); |
| 961 | SCI->eraseFromParent(); |
| 962 | return; |
| 963 | } |
| 964 | |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 965 | // Handle 'getelementptr Ptr, Idx, uint FieldNo ...' |
| 966 | if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(LoadUser)) { |
| 967 | assert(GEPI->getNumOperands() >= 3 && isa<ConstantInt>(GEPI->getOperand(2)) |
| 968 | && "Unexpected GEPI!"); |
Chris Lattner | 330245e | 2007-09-13 17:29:05 +0000 | [diff] [blame] | 969 | |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 970 | // Load the pointer for this field. |
| 971 | unsigned FieldNo = cast<ConstantInt>(GEPI->getOperand(2))->getZExtValue(); |
| 972 | Value *NewPtr = GetHeapSROALoad(Load, FieldNo, |
| 973 | FieldGlobals, InsertedLoadsForPtr); |
| 974 | |
| 975 | // Create the new GEP idx vector. |
| 976 | SmallVector<Value*, 8> GEPIdx; |
| 977 | GEPIdx.push_back(GEPI->getOperand(1)); |
| 978 | GEPIdx.append(GEPI->op_begin()+3, GEPI->op_end()); |
| 979 | |
| 980 | Value *NGEPI = new GetElementPtrInst(NewPtr, GEPIdx.begin(), GEPIdx.end(), |
| 981 | GEPI->getName(), GEPI); |
| 982 | GEPI->replaceAllUsesWith(NGEPI); |
| 983 | GEPI->eraseFromParent(); |
| 984 | return; |
| 985 | } |
Chris Lattner | 330245e | 2007-09-13 17:29:05 +0000 | [diff] [blame] | 986 | |
Chris Lattner | 309f20f | 2007-09-13 21:31:36 +0000 | [diff] [blame] | 987 | // Handle PHI nodes. PHI nodes must be merging in the same values, plus |
| 988 | // potentially the original malloc. Insert phi nodes for each field, then |
| 989 | // process uses of the PHI. |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 990 | PHINode *PN = cast<PHINode>(LoadUser); |
Chris Lattner | 309f20f | 2007-09-13 21:31:36 +0000 | [diff] [blame] | 991 | std::vector<Value *> PHIsForField; |
| 992 | PHIsForField.resize(FieldGlobals.size()); |
| 993 | for (unsigned i = 0, e = FieldGlobals.size(); i != e; ++i) { |
| 994 | Value *LoadV = GetHeapSROALoad(Load, i, FieldGlobals, InsertedLoadsForPtr); |
| 995 | |
| 996 | PHINode *FieldPN = new PHINode(LoadV->getType(), |
| 997 | PN->getName()+"."+utostr(i), PN); |
| 998 | // Fill in the predecessor values. |
| 999 | for (unsigned pred = 0, e = PN->getNumIncomingValues(); pred != e; ++pred) { |
| 1000 | // Each predecessor either uses the load or the original malloc. |
| 1001 | Value *InVal = PN->getIncomingValue(pred); |
| 1002 | BasicBlock *BB = PN->getIncomingBlock(pred); |
| 1003 | Value *NewVal; |
| 1004 | if (isa<MallocInst>(InVal)) { |
| 1005 | // Insert a reload from the global in the predecessor. |
| 1006 | NewVal = GetHeapSROALoad(BB->getTerminator(), i, FieldGlobals, |
| 1007 | PHIsForField); |
| 1008 | } else { |
| 1009 | NewVal = InsertedLoadsForPtr[i]; |
| 1010 | } |
| 1011 | FieldPN->addIncoming(NewVal, BB); |
| 1012 | } |
| 1013 | PHIsForField[i] = FieldPN; |
| 1014 | } |
| 1015 | |
| 1016 | // Since PHIsForField specifies a phi for every input value, the lazy inserter |
| 1017 | // will never insert a load. |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 1018 | while (!PN->use_empty()) |
Chris Lattner | 309f20f | 2007-09-13 21:31:36 +0000 | [diff] [blame] | 1019 | RewriteHeapSROALoadUser(Load, PN->use_back(), FieldGlobals, PHIsForField); |
Chris Lattner | a637a8b | 2007-09-13 18:00:31 +0000 | [diff] [blame] | 1020 | PN->eraseFromParent(); |
Chris Lattner | 330245e | 2007-09-13 17:29:05 +0000 | [diff] [blame] | 1021 | } |
| 1022 | |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1023 | /// RewriteUsesOfLoadForHeapSRoA - We are performing Heap SRoA on a global. Ptr |
| 1024 | /// is a value loaded from the global. Eliminate all uses of Ptr, making them |
| 1025 | /// use FieldGlobals instead. All uses of loaded values satisfy |
| 1026 | /// GlobalLoadUsesSimpleEnoughForHeapSRA. |
Chris Lattner | 330245e | 2007-09-13 17:29:05 +0000 | [diff] [blame] | 1027 | static void RewriteUsesOfLoadForHeapSRoA(LoadInst *Load, |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1028 | const std::vector<GlobalVariable*> &FieldGlobals) { |
| 1029 | std::vector<Value *> InsertedLoadsForPtr; |
| 1030 | //InsertedLoadsForPtr.resize(FieldGlobals.size()); |
Chris Lattner | 330245e | 2007-09-13 17:29:05 +0000 | [diff] [blame] | 1031 | while (!Load->use_empty()) |
| 1032 | RewriteHeapSROALoadUser(Load, Load->use_back(), |
| 1033 | FieldGlobals, InsertedLoadsForPtr); |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1034 | } |
| 1035 | |
| 1036 | /// PerformHeapAllocSRoA - MI is an allocation of an array of structures. Break |
| 1037 | /// it up into multiple allocations of arrays of the fields. |
| 1038 | static GlobalVariable *PerformHeapAllocSRoA(GlobalVariable *GV, MallocInst *MI){ |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 1039 | DOUT << "SROA HEAP ALLOC: " << *GV << " MALLOC = " << *MI; |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1040 | const StructType *STy = cast<StructType>(MI->getAllocatedType()); |
| 1041 | |
| 1042 | // There is guaranteed to be at least one use of the malloc (storing |
| 1043 | // it into GV). If there are other uses, change them to be uses of |
| 1044 | // the global to simplify later code. This also deletes the store |
| 1045 | // into GV. |
| 1046 | ReplaceUsesOfMallocWithGlobal(MI, GV); |
| 1047 | |
| 1048 | // Okay, at this point, there are no users of the malloc. Insert N |
| 1049 | // new mallocs at the same place as MI, and N globals. |
| 1050 | std::vector<GlobalVariable*> FieldGlobals; |
| 1051 | std::vector<MallocInst*> FieldMallocs; |
| 1052 | |
| 1053 | for (unsigned FieldNo = 0, e = STy->getNumElements(); FieldNo != e;++FieldNo){ |
| 1054 | const Type *FieldTy = STy->getElementType(FieldNo); |
Christopher Lamb | 43ad6b3 | 2007-12-17 01:12:55 +0000 | [diff] [blame] | 1055 | const Type *PFieldTy = PointerType::getUnqual(FieldTy); |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1056 | |
| 1057 | GlobalVariable *NGV = |
| 1058 | new GlobalVariable(PFieldTy, false, GlobalValue::InternalLinkage, |
| 1059 | Constant::getNullValue(PFieldTy), |
Lauro Ramos Venancio | c763552 | 2007-04-12 18:32:50 +0000 | [diff] [blame] | 1060 | GV->getName() + ".f" + utostr(FieldNo), GV, |
| 1061 | GV->isThreadLocal()); |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1062 | FieldGlobals.push_back(NGV); |
| 1063 | |
| 1064 | MallocInst *NMI = new MallocInst(FieldTy, MI->getArraySize(), |
| 1065 | MI->getName() + ".f" + utostr(FieldNo),MI); |
| 1066 | FieldMallocs.push_back(NMI); |
| 1067 | new StoreInst(NMI, NGV, MI); |
| 1068 | } |
| 1069 | |
| 1070 | // The tricky aspect of this transformation is handling the case when malloc |
| 1071 | // fails. In the original code, malloc failing would set the result pointer |
| 1072 | // of malloc to null. In this case, some mallocs could succeed and others |
| 1073 | // could fail. As such, we emit code that looks like this: |
| 1074 | // F0 = malloc(field0) |
| 1075 | // F1 = malloc(field1) |
| 1076 | // F2 = malloc(field2) |
| 1077 | // if (F0 == 0 || F1 == 0 || F2 == 0) { |
| 1078 | // if (F0) { free(F0); F0 = 0; } |
| 1079 | // if (F1) { free(F1); F1 = 0; } |
| 1080 | // if (F2) { free(F2); F2 = 0; } |
| 1081 | // } |
| 1082 | Value *RunningOr = 0; |
| 1083 | for (unsigned i = 0, e = FieldMallocs.size(); i != e; ++i) { |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 1084 | Value *Cond = new ICmpInst(ICmpInst::ICMP_EQ, FieldMallocs[i], |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1085 | Constant::getNullValue(FieldMallocs[i]->getType()), |
| 1086 | "isnull", MI); |
| 1087 | if (!RunningOr) |
| 1088 | RunningOr = Cond; // First seteq |
| 1089 | else |
| 1090 | RunningOr = BinaryOperator::createOr(RunningOr, Cond, "tmp", MI); |
| 1091 | } |
| 1092 | |
| 1093 | // Split the basic block at the old malloc. |
| 1094 | BasicBlock *OrigBB = MI->getParent(); |
| 1095 | BasicBlock *ContBB = OrigBB->splitBasicBlock(MI, "malloc_cont"); |
| 1096 | |
| 1097 | // Create the block to check the first condition. Put all these blocks at the |
| 1098 | // end of the function as they are unlikely to be executed. |
| 1099 | BasicBlock *NullPtrBlock = new BasicBlock("malloc_ret_null", |
| 1100 | OrigBB->getParent()); |
| 1101 | |
| 1102 | // Remove the uncond branch from OrigBB to ContBB, turning it into a cond |
| 1103 | // branch on RunningOr. |
| 1104 | OrigBB->getTerminator()->eraseFromParent(); |
| 1105 | new BranchInst(NullPtrBlock, ContBB, RunningOr, OrigBB); |
| 1106 | |
| 1107 | // Within the NullPtrBlock, we need to emit a comparison and branch for each |
| 1108 | // pointer, because some may be null while others are not. |
| 1109 | for (unsigned i = 0, e = FieldGlobals.size(); i != e; ++i) { |
| 1110 | Value *GVVal = new LoadInst(FieldGlobals[i], "tmp", NullPtrBlock); |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 1111 | Value *Cmp = new ICmpInst(ICmpInst::ICMP_NE, GVVal, |
| 1112 | Constant::getNullValue(GVVal->getType()), |
| 1113 | "tmp", NullPtrBlock); |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1114 | BasicBlock *FreeBlock = new BasicBlock("free_it", OrigBB->getParent()); |
| 1115 | BasicBlock *NextBlock = new BasicBlock("next", OrigBB->getParent()); |
| 1116 | new BranchInst(FreeBlock, NextBlock, Cmp, NullPtrBlock); |
| 1117 | |
| 1118 | // Fill in FreeBlock. |
| 1119 | new FreeInst(GVVal, FreeBlock); |
| 1120 | new StoreInst(Constant::getNullValue(GVVal->getType()), FieldGlobals[i], |
| 1121 | FreeBlock); |
| 1122 | new BranchInst(NextBlock, FreeBlock); |
| 1123 | |
| 1124 | NullPtrBlock = NextBlock; |
| 1125 | } |
| 1126 | |
| 1127 | new BranchInst(ContBB, NullPtrBlock); |
| 1128 | |
| 1129 | |
| 1130 | // MI is no longer needed, remove it. |
| 1131 | MI->eraseFromParent(); |
| 1132 | |
| 1133 | |
| 1134 | // Okay, the malloc site is completely handled. All of the uses of GV are now |
| 1135 | // loads, and all uses of those loads are simple. Rewrite them to use loads |
| 1136 | // of the per-field globals instead. |
| 1137 | while (!GV->use_empty()) { |
Chris Lattner | 39ff1e2 | 2007-01-09 23:29:37 +0000 | [diff] [blame] | 1138 | if (LoadInst *LI = dyn_cast<LoadInst>(GV->use_back())) { |
| 1139 | RewriteUsesOfLoadForHeapSRoA(LI, FieldGlobals); |
| 1140 | LI->eraseFromParent(); |
| 1141 | } else { |
| 1142 | // Must be a store of null. |
| 1143 | StoreInst *SI = cast<StoreInst>(GV->use_back()); |
| 1144 | assert(isa<Constant>(SI->getOperand(0)) && |
| 1145 | cast<Constant>(SI->getOperand(0))->isNullValue() && |
| 1146 | "Unexpected heap-sra user!"); |
| 1147 | |
| 1148 | // Insert a store of null into each global. |
| 1149 | for (unsigned i = 0, e = FieldGlobals.size(); i != e; ++i) { |
| 1150 | Constant *Null = |
| 1151 | Constant::getNullValue(FieldGlobals[i]->getType()->getElementType()); |
| 1152 | new StoreInst(Null, FieldGlobals[i], SI); |
| 1153 | } |
| 1154 | // Erase the original store. |
| 1155 | SI->eraseFromParent(); |
| 1156 | } |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1157 | } |
| 1158 | |
| 1159 | // The old global is now dead, remove it. |
| 1160 | GV->eraseFromParent(); |
| 1161 | |
| 1162 | ++NumHeapSRA; |
| 1163 | return FieldGlobals[0]; |
| 1164 | } |
| 1165 | |
| 1166 | |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 1167 | // OptimizeOnceStoredGlobal - Try to optimize globals based on the knowledge |
| 1168 | // that only one value (besides its initializer) is ever stored to the global. |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 1169 | static bool OptimizeOnceStoredGlobal(GlobalVariable *GV, Value *StoredOnceVal, |
Chris Lattner | 7f8897f | 2006-08-27 22:42:52 +0000 | [diff] [blame] | 1170 | Module::global_iterator &GVI, |
| 1171 | TargetData &TD) { |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 1172 | if (CastInst *CI = dyn_cast<CastInst>(StoredOnceVal)) |
| 1173 | StoredOnceVal = CI->getOperand(0); |
| 1174 | else if (GetElementPtrInst *GEPI =dyn_cast<GetElementPtrInst>(StoredOnceVal)){ |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 1175 | // "getelementptr Ptr, 0, 0, 0" is really just a cast. |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 1176 | bool IsJustACast = true; |
| 1177 | for (unsigned i = 1, e = GEPI->getNumOperands(); i != e; ++i) |
| 1178 | if (!isa<Constant>(GEPI->getOperand(i)) || |
| 1179 | !cast<Constant>(GEPI->getOperand(i))->isNullValue()) { |
| 1180 | IsJustACast = false; |
| 1181 | break; |
| 1182 | } |
| 1183 | if (IsJustACast) |
| 1184 | StoredOnceVal = GEPI->getOperand(0); |
| 1185 | } |
| 1186 | |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 1187 | // If we are dealing with a pointer global that is initialized to null and |
| 1188 | // only has one (non-null) value stored into it, then we can optimize any |
| 1189 | // users of the loaded value (often calls and loads) that would trap if the |
| 1190 | // value was null. |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 1191 | if (isa<PointerType>(GV->getInitializer()->getType()) && |
| 1192 | GV->getInitializer()->isNullValue()) { |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 1193 | if (Constant *SOVC = dyn_cast<Constant>(StoredOnceVal)) { |
| 1194 | if (GV->getInitializer()->getType() != SOVC->getType()) |
Reid Spencer | d977d86 | 2006-12-12 23:36:14 +0000 | [diff] [blame] | 1195 | SOVC = ConstantExpr::getBitCast(SOVC, GV->getInitializer()->getType()); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 1196 | |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 1197 | // Optimize away any trapping uses of the loaded value. |
| 1198 | if (OptimizeAwayTrappingUsesOfLoads(GV, SOVC)) |
Chris Lattner | 8be8012 | 2004-10-10 17:07:12 +0000 | [diff] [blame] | 1199 | return true; |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 1200 | } else if (MallocInst *MI = dyn_cast<MallocInst>(StoredOnceVal)) { |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1201 | // If this is a malloc of an abstract type, don't touch it. |
| 1202 | if (!MI->getAllocatedType()->isSized()) |
| 1203 | return false; |
| 1204 | |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1205 | // We can't optimize this global unless all uses of it are *known* to be |
| 1206 | // of the malloc value, not of the null initializer value (consider a use |
| 1207 | // that compares the global's value against zero to see if the malloc has |
| 1208 | // been reached). To do this, we check to see if all uses of the global |
| 1209 | // would trap if the global were null: this proves that they must all |
| 1210 | // happen after the malloc. |
| 1211 | if (!AllUsesOfLoadedValueWillTrapIfNull(GV)) |
| 1212 | return false; |
| 1213 | |
| 1214 | // We can't optimize this if the malloc itself is used in a complex way, |
| 1215 | // for example, being stored into multiple globals. This allows the |
| 1216 | // malloc to be stored into the specified global, loaded setcc'd, and |
| 1217 | // GEP'd. These are all things we could transform to using the global |
| 1218 | // for. |
Chris Lattner | c451f9c | 2007-09-13 16:37:20 +0000 | [diff] [blame] | 1219 | { |
| 1220 | SmallPtrSet<PHINode*, 8> PHIs; |
| 1221 | if (!ValueIsOnlyUsedLocallyOrStoredToOneGlobal(MI, GV, PHIs)) |
| 1222 | return false; |
| 1223 | } |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1224 | |
| 1225 | |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 1226 | // If we have a global that is only initialized with a fixed size malloc, |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1227 | // transform the program to use global memory instead of malloc'd memory. |
| 1228 | // This eliminates dynamic allocation, avoids an indirection accessing the |
| 1229 | // data, and exposes the resultant global to further GlobalOpt. |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1230 | if (ConstantInt *NElements = dyn_cast<ConstantInt>(MI->getArraySize())) { |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1231 | // Restrict this transformation to only working on small allocations |
| 1232 | // (2048 bytes currently), as we don't want to introduce a 16M global or |
| 1233 | // something. |
Reid Spencer | b83eb64 | 2006-10-20 07:07:24 +0000 | [diff] [blame] | 1234 | if (NElements->getZExtValue()* |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 1235 | TD.getABITypeSize(MI->getAllocatedType()) < 2048) { |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 1236 | GVI = OptimizeGlobalAddressOfMalloc(GV, MI); |
| 1237 | return true; |
| 1238 | } |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1239 | } |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1240 | |
| 1241 | // If the allocation is an array of structures, consider transforming this |
| 1242 | // into multiple malloc'd arrays, one for each field. This is basically |
| 1243 | // SRoA for malloc'd memory. |
| 1244 | if (const StructType *AllocTy = |
| 1245 | dyn_cast<StructType>(MI->getAllocatedType())) { |
| 1246 | // This the structure has an unreasonable number of fields, leave it |
| 1247 | // alone. |
| 1248 | if (AllocTy->getNumElements() <= 16 && AllocTy->getNumElements() > 0 && |
Chris Lattner | 309f20f | 2007-09-13 21:31:36 +0000 | [diff] [blame] | 1249 | GlobalLoadUsesSimpleEnoughForHeapSRA(GV, MI)) { |
Chris Lattner | 8639503 | 2006-09-30 23:32:09 +0000 | [diff] [blame] | 1250 | GVI = PerformHeapAllocSRoA(GV, MI); |
| 1251 | return true; |
| 1252 | } |
| 1253 | } |
Chris Lattner | 708148e | 2004-10-10 23:14:11 +0000 | [diff] [blame] | 1254 | } |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 1255 | } |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 1256 | |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 1257 | return false; |
| 1258 | } |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1259 | |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1260 | /// ShrinkGlobalToBoolean - At this point, we have learned that the only two |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 1261 | /// values ever stored into GV are its initializer and OtherVal. |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1262 | static void ShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) { |
| 1263 | // Create the new global, initializing it to false. |
Reid Spencer | 4fe16d6 | 2007-01-11 18:21:29 +0000 | [diff] [blame] | 1264 | GlobalVariable *NewGV = new GlobalVariable(Type::Int1Ty, false, |
Zhou Sheng | 6b6b6ef | 2007-01-11 12:24:14 +0000 | [diff] [blame] | 1265 | GlobalValue::InternalLinkage, ConstantInt::getFalse(), |
Lauro Ramos Venancio | c763552 | 2007-04-12 18:32:50 +0000 | [diff] [blame] | 1266 | GV->getName()+".b", |
| 1267 | (Module *)NULL, |
| 1268 | GV->isThreadLocal()); |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1269 | GV->getParent()->getGlobalList().insert(GV, NewGV); |
| 1270 | |
| 1271 | Constant *InitVal = GV->getInitializer(); |
Reid Spencer | 4fe16d6 | 2007-01-11 18:21:29 +0000 | [diff] [blame] | 1272 | assert(InitVal->getType() != Type::Int1Ty && "No reason to shrink to bool!"); |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1273 | |
| 1274 | // If initialized to zero and storing one into the global, we can use a cast |
| 1275 | // instead of a select to synthesize the desired value. |
| 1276 | bool IsOneZero = false; |
| 1277 | if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)) |
Reid Spencer | cae5754 | 2007-03-02 00:28:52 +0000 | [diff] [blame] | 1278 | IsOneZero = InitVal->isNullValue() && CI->isOne(); |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1279 | |
| 1280 | while (!GV->use_empty()) { |
| 1281 | Instruction *UI = cast<Instruction>(GV->use_back()); |
| 1282 | if (StoreInst *SI = dyn_cast<StoreInst>(UI)) { |
| 1283 | // Change the store into a boolean store. |
| 1284 | bool StoringOther = SI->getOperand(0) == OtherVal; |
| 1285 | // Only do this if we weren't storing a loaded value. |
Chris Lattner | 38c2556 | 2004-12-12 19:34:41 +0000 | [diff] [blame] | 1286 | Value *StoreVal; |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1287 | if (StoringOther || SI->getOperand(0) == InitVal) |
Reid Spencer | 579dca1 | 2007-01-12 04:24:46 +0000 | [diff] [blame] | 1288 | StoreVal = ConstantInt::get(Type::Int1Ty, StoringOther); |
Chris Lattner | 38c2556 | 2004-12-12 19:34:41 +0000 | [diff] [blame] | 1289 | else { |
| 1290 | // Otherwise, we are storing a previously loaded copy. To do this, |
| 1291 | // change the copy from copying the original value to just copying the |
| 1292 | // bool. |
| 1293 | Instruction *StoredVal = cast<Instruction>(SI->getOperand(0)); |
| 1294 | |
| 1295 | // If we're already replaced the input, StoredVal will be a cast or |
| 1296 | // select instruction. If not, it will be a load of the original |
| 1297 | // global. |
| 1298 | if (LoadInst *LI = dyn_cast<LoadInst>(StoredVal)) { |
| 1299 | assert(LI->getOperand(0) == GV && "Not a copy!"); |
| 1300 | // Insert a new load, to preserve the saved value. |
| 1301 | StoreVal = new LoadInst(NewGV, LI->getName()+".b", LI); |
| 1302 | } else { |
| 1303 | assert((isa<CastInst>(StoredVal) || isa<SelectInst>(StoredVal)) && |
| 1304 | "This is not a form that we understand!"); |
| 1305 | StoreVal = StoredVal->getOperand(0); |
| 1306 | assert(isa<LoadInst>(StoreVal) && "Not a load of NewGV!"); |
| 1307 | } |
| 1308 | } |
| 1309 | new StoreInst(StoreVal, NewGV, SI); |
| 1310 | } else if (!UI->use_empty()) { |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1311 | // Change the load into a load of bool then a select. |
| 1312 | LoadInst *LI = cast<LoadInst>(UI); |
Chris Lattner | 046800a | 2007-02-11 01:08:35 +0000 | [diff] [blame] | 1313 | LoadInst *NLI = new LoadInst(NewGV, LI->getName()+".b", LI); |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1314 | Value *NSI; |
| 1315 | if (IsOneZero) |
Chris Lattner | 046800a | 2007-02-11 01:08:35 +0000 | [diff] [blame] | 1316 | NSI = new ZExtInst(NLI, LI->getType(), "", LI); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 1317 | else |
Chris Lattner | 046800a | 2007-02-11 01:08:35 +0000 | [diff] [blame] | 1318 | NSI = new SelectInst(NLI, OtherVal, InitVal, "", LI); |
| 1319 | NSI->takeName(LI); |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1320 | LI->replaceAllUsesWith(NSI); |
| 1321 | } |
| 1322 | UI->eraseFromParent(); |
| 1323 | } |
| 1324 | |
| 1325 | GV->eraseFromParent(); |
| 1326 | } |
| 1327 | |
| 1328 | |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1329 | /// ProcessInternalGlobal - Analyze the specified global variable and optimize |
| 1330 | /// it if possible. If we make a change, return true. |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 1331 | bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV, |
Chris Lattner | e4d5c44 | 2005-03-15 04:54:21 +0000 | [diff] [blame] | 1332 | Module::global_iterator &GVI) { |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1333 | std::set<PHINode*> PHIUsers; |
| 1334 | GlobalStatus GS; |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1335 | GV->removeDeadConstantUsers(); |
| 1336 | |
| 1337 | if (GV->use_empty()) { |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 1338 | DOUT << "GLOBAL DEAD: " << *GV; |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 1339 | GV->eraseFromParent(); |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1340 | ++NumDeleted; |
| 1341 | return true; |
| 1342 | } |
| 1343 | |
| 1344 | if (!AnalyzeGlobal(GV, GS, PHIUsers)) { |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1345 | #if 0 |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 1346 | cerr << "Global: " << *GV; |
| 1347 | cerr << " isLoaded = " << GS.isLoaded << "\n"; |
| 1348 | cerr << " StoredType = "; |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1349 | switch (GS.StoredType) { |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 1350 | case GlobalStatus::NotStored: cerr << "NEVER STORED\n"; break; |
| 1351 | case GlobalStatus::isInitializerStored: cerr << "INIT STORED\n"; break; |
| 1352 | case GlobalStatus::isStoredOnce: cerr << "STORED ONCE\n"; break; |
| 1353 | case GlobalStatus::isStored: cerr << "stored\n"; break; |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1354 | } |
| 1355 | if (GS.StoredType == GlobalStatus::isStoredOnce && GS.StoredOnceValue) |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 1356 | cerr << " StoredOnceValue = " << *GS.StoredOnceValue << "\n"; |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1357 | if (GS.AccessingFunction && !GS.HasMultipleAccessingFunctions) |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 1358 | cerr << " AccessingFunction = " << GS.AccessingFunction->getName() |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1359 | << "\n"; |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 1360 | cerr << " HasMultipleAccessingFunctions = " |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1361 | << GS.HasMultipleAccessingFunctions << "\n"; |
Bill Wendling | e815619 | 2006-12-07 01:30:32 +0000 | [diff] [blame] | 1362 | cerr << " HasNonInstructionUser = " << GS.HasNonInstructionUser<<"\n"; |
| 1363 | cerr << " isNotSuitableForSRA = " << GS.isNotSuitableForSRA << "\n"; |
| 1364 | cerr << "\n"; |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1365 | #endif |
| 1366 | |
Alkis Evlogimenos | f64ea9d | 2005-02-10 18:36:30 +0000 | [diff] [blame] | 1367 | // If this is a first class global and has only one accessing function |
| 1368 | // and this function is main (which we know is not recursive we can make |
| 1369 | // this global a local variable) we replace the global with a local alloca |
| 1370 | // in this function. |
| 1371 | // |
| 1372 | // NOTE: It doesn't make sense to promote non first class types since we |
| 1373 | // are just replacing static memory to stack memory. |
| 1374 | if (!GS.HasMultipleAccessingFunctions && |
Chris Lattner | 553ca52 | 2005-06-15 21:11:48 +0000 | [diff] [blame] | 1375 | GS.AccessingFunction && !GS.HasNonInstructionUser && |
Alkis Evlogimenos | f64ea9d | 2005-02-10 18:36:30 +0000 | [diff] [blame] | 1376 | GV->getType()->getElementType()->isFirstClassType() && |
| 1377 | GS.AccessingFunction->getName() == "main" && |
| 1378 | GS.AccessingFunction->hasExternalLinkage()) { |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 1379 | DOUT << "LOCALIZING GLOBAL: " << *GV; |
Alkis Evlogimenos | f64ea9d | 2005-02-10 18:36:30 +0000 | [diff] [blame] | 1380 | Instruction* FirstI = GS.AccessingFunction->getEntryBlock().begin(); |
| 1381 | const Type* ElemTy = GV->getType()->getElementType(); |
Nate Begeman | 14b0529 | 2005-11-05 09:21:28 +0000 | [diff] [blame] | 1382 | // FIXME: Pass Global's alignment when globals have alignment |
Alkis Evlogimenos | f64ea9d | 2005-02-10 18:36:30 +0000 | [diff] [blame] | 1383 | AllocaInst* Alloca = new AllocaInst(ElemTy, NULL, GV->getName(), FirstI); |
| 1384 | if (!isa<UndefValue>(GV->getInitializer())) |
| 1385 | new StoreInst(GV->getInitializer(), Alloca, FirstI); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 1386 | |
Alkis Evlogimenos | f64ea9d | 2005-02-10 18:36:30 +0000 | [diff] [blame] | 1387 | GV->replaceAllUsesWith(Alloca); |
| 1388 | GV->eraseFromParent(); |
| 1389 | ++NumLocalized; |
| 1390 | return true; |
| 1391 | } |
Chris Lattner | cff1673 | 2006-09-30 19:40:30 +0000 | [diff] [blame] | 1392 | |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1393 | // If the global is never loaded (but may be stored to), it is dead. |
| 1394 | // Delete it now. |
| 1395 | if (!GS.isLoaded) { |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 1396 | DOUT << "GLOBAL NEVER LOADED: " << *GV; |
Chris Lattner | 930f475 | 2004-10-09 03:32:52 +0000 | [diff] [blame] | 1397 | |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1398 | // Delete any stores we can find to the global. We may not be able to |
| 1399 | // make it completely dead though. |
Chris Lattner | 031955d | 2004-10-10 16:43:46 +0000 | [diff] [blame] | 1400 | bool Changed = CleanupConstantGlobalUsers(GV, GV->getInitializer()); |
Chris Lattner | 930f475 | 2004-10-09 03:32:52 +0000 | [diff] [blame] | 1401 | |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1402 | // If the global is dead now, delete it. |
| 1403 | if (GV->use_empty()) { |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 1404 | GV->eraseFromParent(); |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1405 | ++NumDeleted; |
Chris Lattner | 930f475 | 2004-10-09 03:32:52 +0000 | [diff] [blame] | 1406 | Changed = true; |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1407 | } |
Chris Lattner | 930f475 | 2004-10-09 03:32:52 +0000 | [diff] [blame] | 1408 | return Changed; |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 1409 | |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1410 | } else if (GS.StoredType <= GlobalStatus::isInitializerStored) { |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 1411 | DOUT << "MARKING CONSTANT: " << *GV; |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1412 | GV->setConstant(true); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 1413 | |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1414 | // Clean up any obviously simplifiable users now. |
| 1415 | CleanupConstantGlobalUsers(GV, GV->getInitializer()); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 1416 | |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1417 | // If the global is dead now, just nuke it. |
| 1418 | if (GV->use_empty()) { |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 1419 | DOUT << " *** Marking constant allowed us to simplify " |
| 1420 | << "all users and delete global!\n"; |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 1421 | GV->eraseFromParent(); |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1422 | ++NumDeleted; |
| 1423 | } |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 1424 | |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1425 | ++NumMarked; |
| 1426 | return true; |
| 1427 | } else if (!GS.isNotSuitableForSRA && |
| 1428 | !GV->getInitializer()->getType()->isFirstClassType()) { |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1429 | if (GlobalVariable *FirstNewGV = SRAGlobal(GV)) { |
| 1430 | GVI = FirstNewGV; // Don't skip the newly produced globals! |
| 1431 | return true; |
| 1432 | } |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 1433 | } else if (GS.StoredType == GlobalStatus::isStoredOnce) { |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1434 | // If the initial value for the global was an undef value, and if only |
| 1435 | // one other value was stored into it, we can just change the |
| 1436 | // initializer to be an undef value, then delete all stores to the |
| 1437 | // global. This allows us to mark it constant. |
| 1438 | if (Constant *SOVConstant = dyn_cast<Constant>(GS.StoredOnceValue)) |
| 1439 | if (isa<UndefValue>(GV->getInitializer())) { |
| 1440 | // Change the initial value here. |
| 1441 | GV->setInitializer(SOVConstant); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 1442 | |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1443 | // Clean up any obviously simplifiable users now. |
| 1444 | CleanupConstantGlobalUsers(GV, GV->getInitializer()); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 1445 | |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1446 | if (GV->use_empty()) { |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 1447 | DOUT << " *** Substituting initializer allowed us to " |
| 1448 | << "simplify all users and delete global!\n"; |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1449 | GV->eraseFromParent(); |
| 1450 | ++NumDeleted; |
| 1451 | } else { |
| 1452 | GVI = GV; |
| 1453 | } |
| 1454 | ++NumSubstitute; |
| 1455 | return true; |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 1456 | } |
Chris Lattner | 7a7ed02 | 2004-10-16 18:09:00 +0000 | [diff] [blame] | 1457 | |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 1458 | // Try to optimize globals based on the knowledge that only one value |
| 1459 | // (besides its initializer) is ever stored to the global. |
Chris Lattner | 30ba569 | 2004-10-11 05:54:41 +0000 | [diff] [blame] | 1460 | if (OptimizeOnceStoredGlobal(GV, GS.StoredOnceValue, GVI, |
| 1461 | getAnalysis<TargetData>())) |
Chris Lattner | 9b34a61 | 2004-10-09 21:48:45 +0000 | [diff] [blame] | 1462 | return true; |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1463 | |
| 1464 | // Otherwise, if the global was not a boolean, we can shrink it to be a |
| 1465 | // boolean. |
| 1466 | if (Constant *SOVConstant = dyn_cast<Constant>(GS.StoredOnceValue)) |
Reid Spencer | 4fe16d6 | 2007-01-11 18:21:29 +0000 | [diff] [blame] | 1467 | if (GV->getType()->getElementType() != Type::Int1Ty && |
Chris Lattner | 25de4e5 | 2006-11-01 18:03:33 +0000 | [diff] [blame] | 1468 | !GV->getType()->getElementType()->isFloatingPoint() && |
Reid Spencer | 9d6565a | 2007-02-15 02:26:10 +0000 | [diff] [blame] | 1469 | !isa<VectorType>(GV->getType()->getElementType()) && |
Chris Lattner | 4913bf4 | 2007-04-05 21:09:42 +0000 | [diff] [blame] | 1470 | !GS.HasPHIUser && !GS.isNotSuitableForSRA) { |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 1471 | DOUT << " *** SHRINKING TO BOOL: " << *GV; |
Chris Lattner | 96a86b2 | 2004-12-12 05:53:50 +0000 | [diff] [blame] | 1472 | ShrinkGlobalToBoolean(GV, SOVConstant); |
| 1473 | ++NumShrunkToBool; |
| 1474 | return true; |
| 1475 | } |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1476 | } |
| 1477 | } |
| 1478 | return false; |
| 1479 | } |
| 1480 | |
Chris Lattner | fb217ad | 2005-05-08 22:18:06 +0000 | [diff] [blame] | 1481 | /// OnlyCalledDirectly - Return true if the specified function is only called |
| 1482 | /// directly. In other words, its address is never taken. |
| 1483 | static bool OnlyCalledDirectly(Function *F) { |
| 1484 | for (Value::use_iterator UI = F->use_begin(), E = F->use_end(); UI != E;++UI){ |
| 1485 | Instruction *User = dyn_cast<Instruction>(*UI); |
| 1486 | if (!User) return false; |
| 1487 | if (!isa<CallInst>(User) && !isa<InvokeInst>(User)) return false; |
| 1488 | |
| 1489 | // See if the function address is passed as an argument. |
| 1490 | for (unsigned i = 1, e = User->getNumOperands(); i != e; ++i) |
| 1491 | if (User->getOperand(i) == F) return false; |
| 1492 | } |
| 1493 | return true; |
| 1494 | } |
| 1495 | |
| 1496 | /// ChangeCalleesToFastCall - Walk all of the direct calls of the specified |
| 1497 | /// function, changing them to FastCC. |
| 1498 | static void ChangeCalleesToFastCall(Function *F) { |
| 1499 | for (Value::use_iterator UI = F->use_begin(), E = F->use_end(); UI != E;++UI){ |
| 1500 | Instruction *User = cast<Instruction>(*UI); |
| 1501 | if (CallInst *CI = dyn_cast<CallInst>(User)) |
| 1502 | CI->setCallingConv(CallingConv::Fast); |
| 1503 | else |
| 1504 | cast<InvokeInst>(User)->setCallingConv(CallingConv::Fast); |
| 1505 | } |
| 1506 | } |
Chris Lattner | a4be1dc | 2004-10-08 20:59:28 +0000 | [diff] [blame] | 1507 | |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 1508 | bool GlobalOpt::OptimizeFunctions(Module &M) { |
| 1509 | bool Changed = false; |
| 1510 | // Optimize functions. |
| 1511 | for (Module::iterator FI = M.begin(), E = M.end(); FI != E; ) { |
| 1512 | Function *F = FI++; |
| 1513 | F->removeDeadConstantUsers(); |
| 1514 | if (F->use_empty() && (F->hasInternalLinkage() || |
| 1515 | F->hasLinkOnceLinkage())) { |
| 1516 | M.getFunctionList().erase(F); |
| 1517 | Changed = true; |
| 1518 | ++NumFnDeleted; |
| 1519 | } else if (F->hasInternalLinkage() && |
| 1520 | F->getCallingConv() == CallingConv::C && !F->isVarArg() && |
| 1521 | OnlyCalledDirectly(F)) { |
| 1522 | // If this function has C calling conventions, is not a varargs |
| 1523 | // function, and is only called directly, promote it to use the Fast |
| 1524 | // calling convention. |
| 1525 | F->setCallingConv(CallingConv::Fast); |
| 1526 | ChangeCalleesToFastCall(F); |
| 1527 | ++NumFastCallFns; |
| 1528 | Changed = true; |
| 1529 | } |
| 1530 | } |
| 1531 | return Changed; |
| 1532 | } |
| 1533 | |
| 1534 | bool GlobalOpt::OptimizeGlobalVars(Module &M) { |
| 1535 | bool Changed = false; |
| 1536 | for (Module::global_iterator GVI = M.global_begin(), E = M.global_end(); |
| 1537 | GVI != E; ) { |
| 1538 | GlobalVariable *GV = GVI++; |
| 1539 | if (!GV->isConstant() && GV->hasInternalLinkage() && |
| 1540 | GV->hasInitializer()) |
| 1541 | Changed |= ProcessInternalGlobal(GV, GVI); |
| 1542 | } |
| 1543 | return Changed; |
| 1544 | } |
| 1545 | |
| 1546 | /// FindGlobalCtors - Find the llvm.globalctors list, verifying that all |
| 1547 | /// initializers have an init priority of 65535. |
| 1548 | GlobalVariable *GlobalOpt::FindGlobalCtors(Module &M) { |
Alkis Evlogimenos | e9c6d36 | 2005-10-25 11:18:06 +0000 | [diff] [blame] | 1549 | for (Module::global_iterator I = M.global_begin(), E = M.global_end(); |
| 1550 | I != E; ++I) |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 1551 | if (I->getName() == "llvm.global_ctors") { |
| 1552 | // Found it, verify it's an array of { int, void()* }. |
| 1553 | const ArrayType *ATy =dyn_cast<ArrayType>(I->getType()->getElementType()); |
| 1554 | if (!ATy) return 0; |
| 1555 | const StructType *STy = dyn_cast<StructType>(ATy->getElementType()); |
| 1556 | if (!STy || STy->getNumElements() != 2 || |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 1557 | STy->getElementType(0) != Type::Int32Ty) return 0; |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 1558 | const PointerType *PFTy = dyn_cast<PointerType>(STy->getElementType(1)); |
| 1559 | if (!PFTy) return 0; |
| 1560 | const FunctionType *FTy = dyn_cast<FunctionType>(PFTy->getElementType()); |
| 1561 | if (!FTy || FTy->getReturnType() != Type::VoidTy || FTy->isVarArg() || |
| 1562 | FTy->getNumParams() != 0) |
| 1563 | return 0; |
| 1564 | |
| 1565 | // Verify that the initializer is simple enough for us to handle. |
| 1566 | if (!I->hasInitializer()) return 0; |
| 1567 | ConstantArray *CA = dyn_cast<ConstantArray>(I->getInitializer()); |
| 1568 | if (!CA) return 0; |
| 1569 | for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) |
| 1570 | if (ConstantStruct *CS = dyn_cast<ConstantStruct>(CA->getOperand(i))) { |
Chris Lattner | 7d8e58f | 2005-09-26 02:19:27 +0000 | [diff] [blame] | 1571 | if (isa<ConstantPointerNull>(CS->getOperand(1))) |
| 1572 | continue; |
| 1573 | |
| 1574 | // Must have a function or null ptr. |
| 1575 | if (!isa<Function>(CS->getOperand(1))) |
| 1576 | return 0; |
| 1577 | |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 1578 | // Init priority must be standard. |
| 1579 | ConstantInt *CI = dyn_cast<ConstantInt>(CS->getOperand(0)); |
Reid Spencer | b83eb64 | 2006-10-20 07:07:24 +0000 | [diff] [blame] | 1580 | if (!CI || CI->getZExtValue() != 65535) |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 1581 | return 0; |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 1582 | } else { |
| 1583 | return 0; |
| 1584 | } |
| 1585 | |
| 1586 | return I; |
| 1587 | } |
| 1588 | return 0; |
| 1589 | } |
| 1590 | |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 1591 | /// ParseGlobalCtors - Given a llvm.global_ctors list that we can understand, |
| 1592 | /// return a list of the functions and null terminator as a vector. |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 1593 | static std::vector<Function*> ParseGlobalCtors(GlobalVariable *GV) { |
| 1594 | ConstantArray *CA = cast<ConstantArray>(GV->getInitializer()); |
| 1595 | std::vector<Function*> Result; |
| 1596 | Result.reserve(CA->getNumOperands()); |
| 1597 | for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) { |
| 1598 | ConstantStruct *CS = cast<ConstantStruct>(CA->getOperand(i)); |
| 1599 | Result.push_back(dyn_cast<Function>(CS->getOperand(1))); |
| 1600 | } |
| 1601 | return Result; |
| 1602 | } |
| 1603 | |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 1604 | /// InstallGlobalCtors - Given a specified llvm.global_ctors list, install the |
| 1605 | /// specified array, returning the new global to use. |
| 1606 | static GlobalVariable *InstallGlobalCtors(GlobalVariable *GCL, |
| 1607 | const std::vector<Function*> &Ctors) { |
| 1608 | // If we made a change, reassemble the initializer list. |
| 1609 | std::vector<Constant*> CSVals; |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 1610 | CSVals.push_back(ConstantInt::get(Type::Int32Ty, 65535)); |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 1611 | CSVals.push_back(0); |
| 1612 | |
| 1613 | // Create the new init list. |
| 1614 | std::vector<Constant*> CAList; |
| 1615 | for (unsigned i = 0, e = Ctors.size(); i != e; ++i) { |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1616 | if (Ctors[i]) { |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 1617 | CSVals[1] = Ctors[i]; |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1618 | } else { |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 1619 | const Type *FTy = FunctionType::get(Type::VoidTy, |
| 1620 | std::vector<const Type*>(), false); |
Christopher Lamb | 43ad6b3 | 2007-12-17 01:12:55 +0000 | [diff] [blame] | 1621 | const PointerType *PFTy = PointerType::getUnqual(FTy); |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 1622 | CSVals[1] = Constant::getNullValue(PFTy); |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 1623 | CSVals[0] = ConstantInt::get(Type::Int32Ty, 2147483647); |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 1624 | } |
| 1625 | CAList.push_back(ConstantStruct::get(CSVals)); |
| 1626 | } |
| 1627 | |
| 1628 | // Create the array initializer. |
| 1629 | const Type *StructTy = |
| 1630 | cast<ArrayType>(GCL->getType()->getElementType())->getElementType(); |
| 1631 | Constant *CA = ConstantArray::get(ArrayType::get(StructTy, CAList.size()), |
| 1632 | CAList); |
| 1633 | |
| 1634 | // If we didn't change the number of elements, don't create a new GV. |
| 1635 | if (CA->getType() == GCL->getInitializer()->getType()) { |
| 1636 | GCL->setInitializer(CA); |
| 1637 | return GCL; |
| 1638 | } |
| 1639 | |
| 1640 | // Create the new global and insert it next to the existing list. |
| 1641 | GlobalVariable *NGV = new GlobalVariable(CA->getType(), GCL->isConstant(), |
Lauro Ramos Venancio | c763552 | 2007-04-12 18:32:50 +0000 | [diff] [blame] | 1642 | GCL->getLinkage(), CA, "", |
| 1643 | (Module *)NULL, |
| 1644 | GCL->isThreadLocal()); |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 1645 | GCL->getParent()->getGlobalList().insert(GCL, NGV); |
Chris Lattner | 046800a | 2007-02-11 01:08:35 +0000 | [diff] [blame] | 1646 | NGV->takeName(GCL); |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 1647 | |
| 1648 | // Nuke the old list, replacing any uses with the new one. |
| 1649 | if (!GCL->use_empty()) { |
| 1650 | Constant *V = NGV; |
| 1651 | if (V->getType() != GCL->getType()) |
Reid Spencer | d977d86 | 2006-12-12 23:36:14 +0000 | [diff] [blame] | 1652 | V = ConstantExpr::getBitCast(V, GCL->getType()); |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 1653 | GCL->replaceAllUsesWith(V); |
| 1654 | } |
| 1655 | GCL->eraseFromParent(); |
| 1656 | |
| 1657 | if (Ctors.size()) |
| 1658 | return NGV; |
| 1659 | else |
| 1660 | return 0; |
| 1661 | } |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1662 | |
| 1663 | |
| 1664 | static Constant *getVal(std::map<Value*, Constant*> &ComputedValues, |
| 1665 | Value *V) { |
| 1666 | if (Constant *CV = dyn_cast<Constant>(V)) return CV; |
| 1667 | Constant *R = ComputedValues[V]; |
| 1668 | assert(R && "Reference to an uncomputed value!"); |
| 1669 | return R; |
| 1670 | } |
| 1671 | |
| 1672 | /// isSimpleEnoughPointerToCommit - Return true if this constant is simple |
| 1673 | /// enough for us to understand. In particular, if it is a cast of something, |
| 1674 | /// we punt. We basically just support direct accesses to globals and GEP's of |
| 1675 | /// globals. This should be kept up to date with CommitValueTo. |
| 1676 | static bool isSimpleEnoughPointerToCommit(Constant *C) { |
Chris Lattner | 231308c | 2005-09-27 04:50:03 +0000 | [diff] [blame] | 1677 | if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) { |
| 1678 | if (!GV->hasExternalLinkage() && !GV->hasInternalLinkage()) |
Anton Korobeynikov | b74ed07 | 2006-09-14 18:23:27 +0000 | [diff] [blame] | 1679 | return false; // do not allow weak/linkonce/dllimport/dllexport linkage. |
Reid Spencer | 5cbf985 | 2007-01-30 20:08:39 +0000 | [diff] [blame] | 1680 | return !GV->isDeclaration(); // reject external globals. |
Chris Lattner | 231308c | 2005-09-27 04:50:03 +0000 | [diff] [blame] | 1681 | } |
Chris Lattner | 798b4d5 | 2005-09-26 06:52:44 +0000 | [diff] [blame] | 1682 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) |
| 1683 | // Handle a constantexpr gep. |
| 1684 | if (CE->getOpcode() == Instruction::GetElementPtr && |
| 1685 | isa<GlobalVariable>(CE->getOperand(0))) { |
| 1686 | GlobalVariable *GV = cast<GlobalVariable>(CE->getOperand(0)); |
Chris Lattner | 231308c | 2005-09-27 04:50:03 +0000 | [diff] [blame] | 1687 | if (!GV->hasExternalLinkage() && !GV->hasInternalLinkage()) |
Anton Korobeynikov | b74ed07 | 2006-09-14 18:23:27 +0000 | [diff] [blame] | 1688 | return false; // do not allow weak/linkonce/dllimport/dllexport linkage. |
Chris Lattner | 798b4d5 | 2005-09-26 06:52:44 +0000 | [diff] [blame] | 1689 | return GV->hasInitializer() && |
| 1690 | ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(), CE); |
| 1691 | } |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1692 | return false; |
| 1693 | } |
| 1694 | |
Chris Lattner | 798b4d5 | 2005-09-26 06:52:44 +0000 | [diff] [blame] | 1695 | /// EvaluateStoreInto - Evaluate a piece of a constantexpr store into a global |
| 1696 | /// initializer. This returns 'Init' modified to reflect 'Val' stored into it. |
| 1697 | /// At this point, the GEP operands of Addr [0, OpNo) have been stepped into. |
| 1698 | static Constant *EvaluateStoreInto(Constant *Init, Constant *Val, |
| 1699 | ConstantExpr *Addr, unsigned OpNo) { |
| 1700 | // Base case of the recursion. |
| 1701 | if (OpNo == Addr->getNumOperands()) { |
| 1702 | assert(Val->getType() == Init->getType() && "Type mismatch!"); |
| 1703 | return Val; |
| 1704 | } |
| 1705 | |
| 1706 | if (const StructType *STy = dyn_cast<StructType>(Init->getType())) { |
| 1707 | std::vector<Constant*> Elts; |
| 1708 | |
| 1709 | // Break up the constant into its elements. |
| 1710 | if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Init)) { |
| 1711 | for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) |
| 1712 | Elts.push_back(CS->getOperand(i)); |
| 1713 | } else if (isa<ConstantAggregateZero>(Init)) { |
| 1714 | for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) |
| 1715 | Elts.push_back(Constant::getNullValue(STy->getElementType(i))); |
| 1716 | } else if (isa<UndefValue>(Init)) { |
| 1717 | for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) |
| 1718 | Elts.push_back(UndefValue::get(STy->getElementType(i))); |
| 1719 | } else { |
| 1720 | assert(0 && "This code is out of sync with " |
| 1721 | " ConstantFoldLoadThroughGEPConstantExpr"); |
| 1722 | } |
| 1723 | |
| 1724 | // Replace the element that we are supposed to. |
Reid Spencer | b83eb64 | 2006-10-20 07:07:24 +0000 | [diff] [blame] | 1725 | ConstantInt *CU = cast<ConstantInt>(Addr->getOperand(OpNo)); |
| 1726 | unsigned Idx = CU->getZExtValue(); |
| 1727 | assert(Idx < STy->getNumElements() && "Struct index out of range!"); |
Chris Lattner | 798b4d5 | 2005-09-26 06:52:44 +0000 | [diff] [blame] | 1728 | Elts[Idx] = EvaluateStoreInto(Elts[Idx], Val, Addr, OpNo+1); |
| 1729 | |
| 1730 | // Return the modified struct. |
Chris Lattner | f0a9aab | 2007-06-04 22:23:42 +0000 | [diff] [blame] | 1731 | return ConstantStruct::get(&Elts[0], Elts.size(), STy->isPacked()); |
Chris Lattner | 798b4d5 | 2005-09-26 06:52:44 +0000 | [diff] [blame] | 1732 | } else { |
| 1733 | ConstantInt *CI = cast<ConstantInt>(Addr->getOperand(OpNo)); |
| 1734 | const ArrayType *ATy = cast<ArrayType>(Init->getType()); |
| 1735 | |
| 1736 | // Break up the array into elements. |
| 1737 | std::vector<Constant*> Elts; |
| 1738 | if (ConstantArray *CA = dyn_cast<ConstantArray>(Init)) { |
| 1739 | for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) |
| 1740 | Elts.push_back(CA->getOperand(i)); |
| 1741 | } else if (isa<ConstantAggregateZero>(Init)) { |
| 1742 | Constant *Elt = Constant::getNullValue(ATy->getElementType()); |
| 1743 | Elts.assign(ATy->getNumElements(), Elt); |
| 1744 | } else if (isa<UndefValue>(Init)) { |
| 1745 | Constant *Elt = UndefValue::get(ATy->getElementType()); |
| 1746 | Elts.assign(ATy->getNumElements(), Elt); |
| 1747 | } else { |
| 1748 | assert(0 && "This code is out of sync with " |
| 1749 | " ConstantFoldLoadThroughGEPConstantExpr"); |
| 1750 | } |
| 1751 | |
Reid Spencer | b83eb64 | 2006-10-20 07:07:24 +0000 | [diff] [blame] | 1752 | assert(CI->getZExtValue() < ATy->getNumElements()); |
| 1753 | Elts[CI->getZExtValue()] = |
| 1754 | EvaluateStoreInto(Elts[CI->getZExtValue()], Val, Addr, OpNo+1); |
Chris Lattner | 798b4d5 | 2005-09-26 06:52:44 +0000 | [diff] [blame] | 1755 | return ConstantArray::get(ATy, Elts); |
| 1756 | } |
| 1757 | } |
| 1758 | |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1759 | /// CommitValueTo - We have decided that Addr (which satisfies the predicate |
| 1760 | /// isSimpleEnoughPointerToCommit) should get Val as its value. Make it happen. |
| 1761 | static void CommitValueTo(Constant *Val, Constant *Addr) { |
Chris Lattner | 798b4d5 | 2005-09-26 06:52:44 +0000 | [diff] [blame] | 1762 | if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) { |
| 1763 | assert(GV->hasInitializer()); |
| 1764 | GV->setInitializer(Val); |
| 1765 | return; |
| 1766 | } |
| 1767 | |
| 1768 | ConstantExpr *CE = cast<ConstantExpr>(Addr); |
| 1769 | GlobalVariable *GV = cast<GlobalVariable>(CE->getOperand(0)); |
| 1770 | |
| 1771 | Constant *Init = GV->getInitializer(); |
| 1772 | Init = EvaluateStoreInto(Init, Val, CE, 2); |
| 1773 | GV->setInitializer(Init); |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1774 | } |
| 1775 | |
Chris Lattner | 562a055 | 2005-09-26 05:16:34 +0000 | [diff] [blame] | 1776 | /// ComputeLoadResult - Return the value that would be computed by a load from |
| 1777 | /// P after the stores reflected by 'memory' have been performed. If we can't |
| 1778 | /// decide, return null. |
Chris Lattner | 04de1cf | 2005-09-26 05:15:37 +0000 | [diff] [blame] | 1779 | static Constant *ComputeLoadResult(Constant *P, |
| 1780 | const std::map<Constant*, Constant*> &Memory) { |
| 1781 | // If this memory location has been recently stored, use the stored value: it |
| 1782 | // is the most up-to-date. |
| 1783 | std::map<Constant*, Constant*>::const_iterator I = Memory.find(P); |
| 1784 | if (I != Memory.end()) return I->second; |
| 1785 | |
| 1786 | // Access it. |
| 1787 | if (GlobalVariable *GV = dyn_cast<GlobalVariable>(P)) { |
| 1788 | if (GV->hasInitializer()) |
| 1789 | return GV->getInitializer(); |
| 1790 | return 0; |
Chris Lattner | 04de1cf | 2005-09-26 05:15:37 +0000 | [diff] [blame] | 1791 | } |
Chris Lattner | 798b4d5 | 2005-09-26 06:52:44 +0000 | [diff] [blame] | 1792 | |
| 1793 | // Handle a constantexpr getelementptr. |
| 1794 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(P)) |
| 1795 | if (CE->getOpcode() == Instruction::GetElementPtr && |
| 1796 | isa<GlobalVariable>(CE->getOperand(0))) { |
| 1797 | GlobalVariable *GV = cast<GlobalVariable>(CE->getOperand(0)); |
| 1798 | if (GV->hasInitializer()) |
| 1799 | return ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(), CE); |
| 1800 | } |
| 1801 | |
| 1802 | return 0; // don't know how to evaluate. |
Chris Lattner | 04de1cf | 2005-09-26 05:15:37 +0000 | [diff] [blame] | 1803 | } |
| 1804 | |
Chris Lattner | 8a7cc6e | 2005-09-27 04:27:01 +0000 | [diff] [blame] | 1805 | /// EvaluateFunction - Evaluate a call to function F, returning true if |
| 1806 | /// successful, false if we can't evaluate it. ActualArgs contains the formal |
| 1807 | /// arguments for the function. |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1808 | static bool EvaluateFunction(Function *F, Constant *&RetVal, |
Chris Lattner | 8a7cc6e | 2005-09-27 04:27:01 +0000 | [diff] [blame] | 1809 | const std::vector<Constant*> &ActualArgs, |
| 1810 | std::vector<Function*> &CallStack, |
| 1811 | std::map<Constant*, Constant*> &MutatedMemory, |
| 1812 | std::vector<GlobalVariable*> &AllocaTmps) { |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1813 | // Check to see if this function is already executing (recursion). If so, |
| 1814 | // bail out. TODO: we might want to accept limited recursion. |
| 1815 | if (std::find(CallStack.begin(), CallStack.end(), F) != CallStack.end()) |
| 1816 | return false; |
| 1817 | |
| 1818 | CallStack.push_back(F); |
| 1819 | |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1820 | /// Values - As we compute SSA register values, we store their contents here. |
| 1821 | std::map<Value*, Constant*> Values; |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1822 | |
| 1823 | // Initialize arguments to the incoming values specified. |
| 1824 | unsigned ArgNo = 0; |
| 1825 | for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end(); AI != E; |
| 1826 | ++AI, ++ArgNo) |
| 1827 | Values[AI] = ActualArgs[ArgNo]; |
Chris Lattner | 8a7cc6e | 2005-09-27 04:27:01 +0000 | [diff] [blame] | 1828 | |
Chris Lattner | cdf98be | 2005-09-26 04:57:38 +0000 | [diff] [blame] | 1829 | /// ExecutedBlocks - We only handle non-looping, non-recursive code. As such, |
| 1830 | /// we can only evaluate any one basic block at most once. This set keeps |
| 1831 | /// track of what we have executed so we can detect recursive cases etc. |
| 1832 | std::set<BasicBlock*> ExecutedBlocks; |
Chris Lattner | a22fdb0 | 2005-09-26 17:07:09 +0000 | [diff] [blame] | 1833 | |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1834 | // CurInst - The current instruction we're evaluating. |
| 1835 | BasicBlock::iterator CurInst = F->begin()->begin(); |
| 1836 | |
| 1837 | // This is the main evaluation loop. |
| 1838 | while (1) { |
| 1839 | Constant *InstResult = 0; |
| 1840 | |
| 1841 | if (StoreInst *SI = dyn_cast<StoreInst>(CurInst)) { |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1842 | if (SI->isVolatile()) return false; // no volatile accesses. |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1843 | Constant *Ptr = getVal(Values, SI->getOperand(1)); |
| 1844 | if (!isSimpleEnoughPointerToCommit(Ptr)) |
| 1845 | // If this is too complex for us to commit, reject it. |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1846 | return false; |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1847 | Constant *Val = getVal(Values, SI->getOperand(0)); |
| 1848 | MutatedMemory[Ptr] = Val; |
| 1849 | } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(CurInst)) { |
| 1850 | InstResult = ConstantExpr::get(BO->getOpcode(), |
| 1851 | getVal(Values, BO->getOperand(0)), |
| 1852 | getVal(Values, BO->getOperand(1))); |
Reid Spencer | e4d87aa | 2006-12-23 06:05:41 +0000 | [diff] [blame] | 1853 | } else if (CmpInst *CI = dyn_cast<CmpInst>(CurInst)) { |
| 1854 | InstResult = ConstantExpr::getCompare(CI->getPredicate(), |
| 1855 | getVal(Values, CI->getOperand(0)), |
| 1856 | getVal(Values, CI->getOperand(1))); |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1857 | } else if (CastInst *CI = dyn_cast<CastInst>(CurInst)) { |
Chris Lattner | 9a989f0 | 2006-11-30 17:26:08 +0000 | [diff] [blame] | 1858 | InstResult = ConstantExpr::getCast(CI->getOpcode(), |
| 1859 | getVal(Values, CI->getOperand(0)), |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1860 | CI->getType()); |
| 1861 | } else if (SelectInst *SI = dyn_cast<SelectInst>(CurInst)) { |
| 1862 | InstResult = ConstantExpr::getSelect(getVal(Values, SI->getOperand(0)), |
| 1863 | getVal(Values, SI->getOperand(1)), |
| 1864 | getVal(Values, SI->getOperand(2))); |
Chris Lattner | 04de1cf | 2005-09-26 05:15:37 +0000 | [diff] [blame] | 1865 | } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(CurInst)) { |
| 1866 | Constant *P = getVal(Values, GEP->getOperand(0)); |
Chris Lattner | 55eb1c4 | 2007-01-31 04:40:53 +0000 | [diff] [blame] | 1867 | SmallVector<Constant*, 8> GEPOps; |
Chris Lattner | 04de1cf | 2005-09-26 05:15:37 +0000 | [diff] [blame] | 1868 | for (unsigned i = 1, e = GEP->getNumOperands(); i != e; ++i) |
| 1869 | GEPOps.push_back(getVal(Values, GEP->getOperand(i))); |
Chris Lattner | 55eb1c4 | 2007-01-31 04:40:53 +0000 | [diff] [blame] | 1870 | InstResult = ConstantExpr::getGetElementPtr(P, &GEPOps[0], GEPOps.size()); |
Chris Lattner | 04de1cf | 2005-09-26 05:15:37 +0000 | [diff] [blame] | 1871 | } else if (LoadInst *LI = dyn_cast<LoadInst>(CurInst)) { |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1872 | if (LI->isVolatile()) return false; // no volatile accesses. |
Chris Lattner | 04de1cf | 2005-09-26 05:15:37 +0000 | [diff] [blame] | 1873 | InstResult = ComputeLoadResult(getVal(Values, LI->getOperand(0)), |
| 1874 | MutatedMemory); |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1875 | if (InstResult == 0) return false; // Could not evaluate load. |
Chris Lattner | a22fdb0 | 2005-09-26 17:07:09 +0000 | [diff] [blame] | 1876 | } else if (AllocaInst *AI = dyn_cast<AllocaInst>(CurInst)) { |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1877 | if (AI->isArrayAllocation()) return false; // Cannot handle array allocs. |
Chris Lattner | a22fdb0 | 2005-09-26 17:07:09 +0000 | [diff] [blame] | 1878 | const Type *Ty = AI->getType()->getElementType(); |
| 1879 | AllocaTmps.push_back(new GlobalVariable(Ty, false, |
| 1880 | GlobalValue::InternalLinkage, |
| 1881 | UndefValue::get(Ty), |
| 1882 | AI->getName())); |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1883 | InstResult = AllocaTmps.back(); |
| 1884 | } else if (CallInst *CI = dyn_cast<CallInst>(CurInst)) { |
Chris Lattner | 7cd580f | 2006-07-07 21:37:01 +0000 | [diff] [blame] | 1885 | // Cannot handle inline asm. |
| 1886 | if (isa<InlineAsm>(CI->getOperand(0))) return false; |
| 1887 | |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1888 | // Resolve function pointers. |
| 1889 | Function *Callee = dyn_cast<Function>(getVal(Values, CI->getOperand(0))); |
| 1890 | if (!Callee) return false; // Cannot resolve. |
Chris Lattner | a9ec8ab | 2005-09-27 05:02:43 +0000 | [diff] [blame] | 1891 | |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1892 | std::vector<Constant*> Formals; |
| 1893 | for (unsigned i = 1, e = CI->getNumOperands(); i != e; ++i) |
| 1894 | Formals.push_back(getVal(Values, CI->getOperand(i))); |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1895 | |
Reid Spencer | 5cbf985 | 2007-01-30 20:08:39 +0000 | [diff] [blame] | 1896 | if (Callee->isDeclaration()) { |
Chris Lattner | a9ec8ab | 2005-09-27 05:02:43 +0000 | [diff] [blame] | 1897 | // If this is a function we can constant fold, do it. |
Chris Lattner | 6c1f565 | 2007-01-30 23:14:52 +0000 | [diff] [blame] | 1898 | if (Constant *C = ConstantFoldCall(Callee, &Formals[0], |
| 1899 | Formals.size())) { |
Chris Lattner | a9ec8ab | 2005-09-27 05:02:43 +0000 | [diff] [blame] | 1900 | InstResult = C; |
| 1901 | } else { |
| 1902 | return false; |
| 1903 | } |
| 1904 | } else { |
| 1905 | if (Callee->getFunctionType()->isVarArg()) |
| 1906 | return false; |
| 1907 | |
| 1908 | Constant *RetVal; |
| 1909 | |
| 1910 | // Execute the call, if successful, use the return value. |
| 1911 | if (!EvaluateFunction(Callee, RetVal, Formals, CallStack, |
| 1912 | MutatedMemory, AllocaTmps)) |
| 1913 | return false; |
| 1914 | InstResult = RetVal; |
| 1915 | } |
Reid Spencer | 3ed469c | 2006-11-02 20:25:50 +0000 | [diff] [blame] | 1916 | } else if (isa<TerminatorInst>(CurInst)) { |
Chris Lattner | cdf98be | 2005-09-26 04:57:38 +0000 | [diff] [blame] | 1917 | BasicBlock *NewBB = 0; |
| 1918 | if (BranchInst *BI = dyn_cast<BranchInst>(CurInst)) { |
| 1919 | if (BI->isUnconditional()) { |
| 1920 | NewBB = BI->getSuccessor(0); |
| 1921 | } else { |
Zhou Sheng | 6b6b6ef | 2007-01-11 12:24:14 +0000 | [diff] [blame] | 1922 | ConstantInt *Cond = |
| 1923 | dyn_cast<ConstantInt>(getVal(Values, BI->getCondition())); |
Chris Lattner | 97d1fad | 2007-01-12 18:30:11 +0000 | [diff] [blame] | 1924 | if (!Cond) return false; // Cannot determine. |
Zhou Sheng | 6b6b6ef | 2007-01-11 12:24:14 +0000 | [diff] [blame] | 1925 | |
Reid Spencer | 579dca1 | 2007-01-12 04:24:46 +0000 | [diff] [blame] | 1926 | NewBB = BI->getSuccessor(!Cond->getZExtValue()); |
Chris Lattner | cdf98be | 2005-09-26 04:57:38 +0000 | [diff] [blame] | 1927 | } |
| 1928 | } else if (SwitchInst *SI = dyn_cast<SwitchInst>(CurInst)) { |
| 1929 | ConstantInt *Val = |
| 1930 | dyn_cast<ConstantInt>(getVal(Values, SI->getCondition())); |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1931 | if (!Val) return false; // Cannot determine. |
Chris Lattner | cdf98be | 2005-09-26 04:57:38 +0000 | [diff] [blame] | 1932 | NewBB = SI->getSuccessor(SI->findCaseValue(Val)); |
| 1933 | } else if (ReturnInst *RI = dyn_cast<ReturnInst>(CurInst)) { |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1934 | if (RI->getNumOperands()) |
| 1935 | RetVal = getVal(Values, RI->getOperand(0)); |
| 1936 | |
| 1937 | CallStack.pop_back(); // return from fn. |
Chris Lattner | 8a7cc6e | 2005-09-27 04:27:01 +0000 | [diff] [blame] | 1938 | return true; // We succeeded at evaluating this ctor! |
Chris Lattner | cdf98be | 2005-09-26 04:57:38 +0000 | [diff] [blame] | 1939 | } else { |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1940 | // invoke, unwind, unreachable. |
| 1941 | return false; // Cannot handle this terminator. |
Chris Lattner | cdf98be | 2005-09-26 04:57:38 +0000 | [diff] [blame] | 1942 | } |
| 1943 | |
| 1944 | // Okay, we succeeded in evaluating this control flow. See if we have |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1945 | // executed the new block before. If so, we have a looping function, |
| 1946 | // which we cannot evaluate in reasonable time. |
Chris Lattner | cdf98be | 2005-09-26 04:57:38 +0000 | [diff] [blame] | 1947 | if (!ExecutedBlocks.insert(NewBB).second) |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1948 | return false; // looped! |
Chris Lattner | cdf98be | 2005-09-26 04:57:38 +0000 | [diff] [blame] | 1949 | |
| 1950 | // Okay, we have never been in this block before. Check to see if there |
| 1951 | // are any PHI nodes. If so, evaluate them with information about where |
| 1952 | // we came from. |
| 1953 | BasicBlock *OldBB = CurInst->getParent(); |
| 1954 | CurInst = NewBB->begin(); |
| 1955 | PHINode *PN; |
| 1956 | for (; (PN = dyn_cast<PHINode>(CurInst)); ++CurInst) |
| 1957 | Values[PN] = getVal(Values, PN->getIncomingValueForBlock(OldBB)); |
| 1958 | |
| 1959 | // Do NOT increment CurInst. We know that the terminator had no value. |
| 1960 | continue; |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1961 | } else { |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1962 | // Did not know how to evaluate this! |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1963 | return false; |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 1964 | } |
| 1965 | |
| 1966 | if (!CurInst->use_empty()) |
| 1967 | Values[CurInst] = InstResult; |
| 1968 | |
| 1969 | // Advance program counter. |
| 1970 | ++CurInst; |
| 1971 | } |
Chris Lattner | 8a7cc6e | 2005-09-27 04:27:01 +0000 | [diff] [blame] | 1972 | } |
| 1973 | |
| 1974 | /// EvaluateStaticConstructor - Evaluate static constructors in the function, if |
| 1975 | /// we can. Return true if we can, false otherwise. |
| 1976 | static bool EvaluateStaticConstructor(Function *F) { |
| 1977 | /// MutatedMemory - For each store we execute, we update this map. Loads |
| 1978 | /// check this to get the most up-to-date value. If evaluation is successful, |
| 1979 | /// this state is committed to the process. |
| 1980 | std::map<Constant*, Constant*> MutatedMemory; |
| 1981 | |
| 1982 | /// AllocaTmps - To 'execute' an alloca, we create a temporary global variable |
| 1983 | /// to represent its body. This vector is needed so we can delete the |
| 1984 | /// temporary globals when we are done. |
| 1985 | std::vector<GlobalVariable*> AllocaTmps; |
| 1986 | |
| 1987 | /// CallStack - This is used to detect recursion. In pathological situations |
| 1988 | /// we could hit exponential behavior, but at least there is nothing |
| 1989 | /// unbounded. |
| 1990 | std::vector<Function*> CallStack; |
| 1991 | |
| 1992 | // Call the function. |
Chris Lattner | cd27142 | 2005-09-27 04:45:34 +0000 | [diff] [blame] | 1993 | Constant *RetValDummy; |
| 1994 | bool EvalSuccess = EvaluateFunction(F, RetValDummy, std::vector<Constant*>(), |
| 1995 | CallStack, MutatedMemory, AllocaTmps); |
Chris Lattner | 8a7cc6e | 2005-09-27 04:27:01 +0000 | [diff] [blame] | 1996 | if (EvalSuccess) { |
Chris Lattner | a22fdb0 | 2005-09-26 17:07:09 +0000 | [diff] [blame] | 1997 | // We succeeded at evaluation: commit the result. |
Bill Wendling | 0a81aac | 2006-11-26 10:02:32 +0000 | [diff] [blame] | 1998 | DOUT << "FULLY EVALUATED GLOBAL CTOR FUNCTION '" |
| 1999 | << F->getName() << "' to " << MutatedMemory.size() |
| 2000 | << " stores.\n"; |
Chris Lattner | a22fdb0 | 2005-09-26 17:07:09 +0000 | [diff] [blame] | 2001 | for (std::map<Constant*, Constant*>::iterator I = MutatedMemory.begin(), |
| 2002 | E = MutatedMemory.end(); I != E; ++I) |
| 2003 | CommitValueTo(I->second, I->first); |
| 2004 | } |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 2005 | |
Chris Lattner | a22fdb0 | 2005-09-26 17:07:09 +0000 | [diff] [blame] | 2006 | // At this point, we are done interpreting. If we created any 'alloca' |
| 2007 | // temporaries, release them now. |
| 2008 | while (!AllocaTmps.empty()) { |
| 2009 | GlobalVariable *Tmp = AllocaTmps.back(); |
| 2010 | AllocaTmps.pop_back(); |
Chris Lattner | 8a7cc6e | 2005-09-27 04:27:01 +0000 | [diff] [blame] | 2011 | |
Chris Lattner | a22fdb0 | 2005-09-26 17:07:09 +0000 | [diff] [blame] | 2012 | // If there are still users of the alloca, the program is doing something |
| 2013 | // silly, e.g. storing the address of the alloca somewhere and using it |
| 2014 | // later. Since this is undefined, we'll just make it be null. |
| 2015 | if (!Tmp->use_empty()) |
| 2016 | Tmp->replaceAllUsesWith(Constant::getNullValue(Tmp->getType())); |
| 2017 | delete Tmp; |
| 2018 | } |
Chris Lattner | aae4a1c | 2005-09-26 07:34:35 +0000 | [diff] [blame] | 2019 | |
Chris Lattner | 8a7cc6e | 2005-09-27 04:27:01 +0000 | [diff] [blame] | 2020 | return EvalSuccess; |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 2021 | } |
| 2022 | |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 2023 | |
Chris Lattner | 8a7cc6e | 2005-09-27 04:27:01 +0000 | [diff] [blame] | 2024 | |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 2025 | /// OptimizeGlobalCtorsList - Simplify and evaluation global ctors if possible. |
| 2026 | /// Return true if anything changed. |
| 2027 | bool GlobalOpt::OptimizeGlobalCtorsList(GlobalVariable *&GCL) { |
| 2028 | std::vector<Function*> Ctors = ParseGlobalCtors(GCL); |
| 2029 | bool MadeChange = false; |
| 2030 | if (Ctors.empty()) return false; |
| 2031 | |
| 2032 | // Loop over global ctors, optimizing them when we can. |
| 2033 | for (unsigned i = 0; i != Ctors.size(); ++i) { |
| 2034 | Function *F = Ctors[i]; |
| 2035 | // Found a null terminator in the middle of the list, prune off the rest of |
| 2036 | // the list. |
Chris Lattner | 7d8e58f | 2005-09-26 02:19:27 +0000 | [diff] [blame] | 2037 | if (F == 0) { |
| 2038 | if (i != Ctors.size()-1) { |
| 2039 | Ctors.resize(i+1); |
| 2040 | MadeChange = true; |
| 2041 | } |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 2042 | break; |
| 2043 | } |
| 2044 | |
Chris Lattner | 79c1101 | 2005-09-26 04:44:35 +0000 | [diff] [blame] | 2045 | // We cannot simplify external ctor functions. |
| 2046 | if (F->empty()) continue; |
| 2047 | |
| 2048 | // If we can evaluate the ctor at compile time, do. |
| 2049 | if (EvaluateStaticConstructor(F)) { |
| 2050 | Ctors.erase(Ctors.begin()+i); |
| 2051 | MadeChange = true; |
| 2052 | --i; |
| 2053 | ++NumCtorsEvaluated; |
| 2054 | continue; |
| 2055 | } |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 2056 | } |
| 2057 | |
| 2058 | if (!MadeChange) return false; |
| 2059 | |
Chris Lattner | db973e6 | 2005-09-26 02:31:18 +0000 | [diff] [blame] | 2060 | GCL = InstallGlobalCtors(GCL, Ctors); |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 2061 | return true; |
| 2062 | } |
| 2063 | |
| 2064 | |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 2065 | bool GlobalOpt::runOnModule(Module &M) { |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 2066 | bool Changed = false; |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 2067 | |
| 2068 | // Try to find the llvm.globalctors list. |
| 2069 | GlobalVariable *GlobalCtors = FindGlobalCtors(M); |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 2070 | |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 2071 | bool LocalChange = true; |
| 2072 | while (LocalChange) { |
| 2073 | LocalChange = false; |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 2074 | |
| 2075 | // Delete functions that are trivially dead, ccc -> fastcc |
| 2076 | LocalChange |= OptimizeFunctions(M); |
| 2077 | |
| 2078 | // Optimize global_ctors list. |
| 2079 | if (GlobalCtors) |
| 2080 | LocalChange |= OptimizeGlobalCtorsList(GlobalCtors); |
| 2081 | |
| 2082 | // Optimize non-address-taken globals. |
| 2083 | LocalChange |= OptimizeGlobalVars(M); |
Chris Lattner | 7a90b68 | 2004-10-07 04:16:33 +0000 | [diff] [blame] | 2084 | Changed |= LocalChange; |
| 2085 | } |
Chris Lattner | b1ab458 | 2005-09-26 01:43:45 +0000 | [diff] [blame] | 2086 | |
| 2087 | // TODO: Move all global ctors functions to the end of the module for code |
| 2088 | // layout. |
| 2089 | |
Chris Lattner | 079236d | 2004-02-25 21:34:36 +0000 | [diff] [blame] | 2090 | return Changed; |
| 2091 | } |