Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 1 | //===- MemoryDependenceAnalysis.cpp - Mem Deps Implementation --*- C++ -*-===// |
| 2 | // |
| 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. |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This file implements an analysis that determines, for a given memory |
| 11 | // operation, what preceding memory operations it depends on. It builds on |
Owen Anderson | 80b1f09 | 2007-08-08 22:01:54 +0000 | [diff] [blame] | 12 | // alias analysis information, and tries to provide a lazy, caching interface to |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 13 | // a common kind of alias information query. |
| 14 | // |
| 15 | //===----------------------------------------------------------------------===// |
| 16 | |
| 17 | #include "llvm/Analysis/MemoryDependenceAnalysis.h" |
Owen Anderson | 7a616a1 | 2007-07-10 17:25:03 +0000 | [diff] [blame] | 18 | #include "llvm/Constants.h" |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 19 | #include "llvm/Instructions.h" |
| 20 | #include "llvm/Function.h" |
| 21 | #include "llvm/Analysis/AliasAnalysis.h" |
Owen Anderson | 4beedbd | 2007-07-24 21:52:37 +0000 | [diff] [blame] | 22 | #include "llvm/Support/CFG.h" |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 23 | #include "llvm/Target/TargetData.h" |
Owen Anderson | 7fad7e3 | 2007-09-09 21:43:49 +0000 | [diff] [blame] | 24 | #include "llvm/ADT/Statistic.h" |
| 25 | |
| 26 | #define DEBUG_TYPE "memdep" |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 27 | |
| 28 | using namespace llvm; |
| 29 | |
Owen Anderson | 7fad7e3 | 2007-09-09 21:43:49 +0000 | [diff] [blame] | 30 | STATISTIC(NumCacheNonlocal, "Number of cached non-local responses"); |
| 31 | STATISTIC(NumUncacheNonlocal, "Number of uncached non-local responses"); |
| 32 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 33 | char MemoryDependenceAnalysis::ID = 0; |
| 34 | |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 35 | Instruction* const MemoryDependenceAnalysis::NonLocal = (Instruction*)-3; |
| 36 | Instruction* const MemoryDependenceAnalysis::None = (Instruction*)-4; |
Owen Anderson | 742f9b6 | 2007-09-19 16:13:57 +0000 | [diff] [blame] | 37 | Instruction* const MemoryDependenceAnalysis::Dirty = (Instruction*)-5; |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 38 | |
| 39 | // Register this pass... |
Owen Anderson | 776ee1f | 2007-07-10 20:21:08 +0000 | [diff] [blame] | 40 | static RegisterPass<MemoryDependenceAnalysis> X("memdep", |
| 41 | "Memory Dependence Analysis"); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 42 | |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 43 | void MemoryDependenceAnalysis::ping(Instruction *D) { |
| 44 | for (depMapType::iterator I = depGraphLocal.begin(), E = depGraphLocal.end(); |
| 45 | I != E; ++I) { |
| 46 | assert(I->first != D); |
| 47 | assert(I->second.first != D); |
| 48 | } |
| 49 | |
| 50 | for (nonLocalDepMapType::iterator I = depGraphNonLocal.begin(), E = depGraphNonLocal.end(); |
| 51 | I != E; ++I) { |
| 52 | assert(I->first != D); |
| 53 | } |
| 54 | |
| 55 | for (reverseDepMapType::iterator I = reverseDep.begin(), E = reverseDep.end(); |
| 56 | I != E; ++I) |
| 57 | for (SmallPtrSet<Instruction*, 4>::iterator II = I->second.begin(), EE = I->second.end(); |
| 58 | II != EE; ++II) |
| 59 | assert(*II != D); |
| 60 | |
| 61 | for (reverseDepMapType::iterator I = reverseDepNonLocal.begin(), E = reverseDepNonLocal.end(); |
| 62 | I != E; ++I) |
| 63 | for (SmallPtrSet<Instruction*, 4>::iterator II = I->second.begin(), EE = I->second.end(); |
| 64 | II != EE; ++II) |
| 65 | assert(*II != D); |
| 66 | } |
| 67 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 68 | /// getAnalysisUsage - Does not modify anything. It uses Alias Analysis. |
| 69 | /// |
| 70 | void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const { |
| 71 | AU.setPreservesAll(); |
| 72 | AU.addRequiredTransitive<AliasAnalysis>(); |
| 73 | AU.addRequiredTransitive<TargetData>(); |
| 74 | } |
| 75 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 76 | /// getCallSiteDependency - Private helper for finding the local dependencies |
| 77 | /// of a call site. |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 78 | Instruction* MemoryDependenceAnalysis::getCallSiteDependency(CallSite C, |
Owen Anderson | 80b1f09 | 2007-08-08 22:01:54 +0000 | [diff] [blame] | 79 | Instruction* start, |
| 80 | BasicBlock* block) { |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 81 | |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 82 | std::pair<Instruction*, bool>& cachedResult = |
| 83 | depGraphLocal[C.getInstruction()]; |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 84 | AliasAnalysis& AA = getAnalysis<AliasAnalysis>(); |
| 85 | TargetData& TD = getAnalysis<TargetData>(); |
| 86 | BasicBlock::iterator blockBegin = C.getInstruction()->getParent()->begin(); |
| 87 | BasicBlock::iterator QI = C.getInstruction(); |
| 88 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 89 | // If the starting point was specifiy, use it |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 90 | if (start) { |
| 91 | QI = start; |
| 92 | blockBegin = start->getParent()->end(); |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 93 | // If the starting point wasn't specified, but the block was, use it |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 94 | } else if (!start && block) { |
| 95 | QI = block->end(); |
| 96 | blockBegin = block->end(); |
| 97 | } |
| 98 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 99 | // Walk backwards through the block, looking for dependencies |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 100 | while (QI != blockBegin) { |
| 101 | --QI; |
| 102 | |
| 103 | // If this inst is a memory op, get the pointer it accessed |
| 104 | Value* pointer = 0; |
| 105 | uint64_t pointerSize = 0; |
| 106 | if (StoreInst* S = dyn_cast<StoreInst>(QI)) { |
| 107 | pointer = S->getPointerOperand(); |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 108 | pointerSize = TD.getTypeStoreSize(S->getOperand(0)->getType()); |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 109 | } else if (AllocationInst* AI = dyn_cast<AllocationInst>(QI)) { |
| 110 | pointer = AI; |
| 111 | if (ConstantInt* C = dyn_cast<ConstantInt>(AI->getArraySize())) |
Owen Anderson | 80b1f09 | 2007-08-08 22:01:54 +0000 | [diff] [blame] | 112 | pointerSize = C->getZExtValue() * \ |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 113 | TD.getABITypeSize(AI->getAllocatedType()); |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 114 | else |
| 115 | pointerSize = ~0UL; |
Owen Anderson | 06b6e82 | 2007-07-10 18:43:15 +0000 | [diff] [blame] | 116 | } else if (VAArgInst* V = dyn_cast<VAArgInst>(QI)) { |
| 117 | pointer = V->getOperand(0); |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 118 | pointerSize = TD.getTypeStoreSize(V->getType()); |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 119 | } else if (FreeInst* F = dyn_cast<FreeInst>(QI)) { |
| 120 | pointer = F->getPointerOperand(); |
| 121 | |
| 122 | // FreeInsts erase the entire structure |
| 123 | pointerSize = ~0UL; |
Duncan Sands | dff6710 | 2007-12-01 07:51:45 +0000 | [diff] [blame] | 124 | } else if (isa<CallInst>(QI)) { |
Owen Anderson | 00a6d14 | 2007-11-26 02:26:36 +0000 | [diff] [blame] | 125 | AliasAnalysis::ModRefBehavior result = |
Duncan Sands | dff6710 | 2007-12-01 07:51:45 +0000 | [diff] [blame] | 126 | AA.getModRefBehavior(CallSite::get(QI)); |
Owen Anderson | 00a6d14 | 2007-11-26 02:26:36 +0000 | [diff] [blame] | 127 | if (result != AliasAnalysis::DoesNotAccessMemory && |
| 128 | result != AliasAnalysis::OnlyReadsMemory) { |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 129 | if (!start && !block) { |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 130 | cachedResult.first = QI; |
| 131 | cachedResult.second = true; |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 132 | reverseDep[QI].insert(C.getInstruction()); |
| 133 | } |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 134 | return QI; |
| 135 | } else { |
| 136 | continue; |
| 137 | } |
Owen Anderson | 202da14 | 2007-07-10 20:39:07 +0000 | [diff] [blame] | 138 | } else |
| 139 | continue; |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 140 | |
| 141 | if (AA.getModRefInfo(C, pointer, pointerSize) != AliasAnalysis::NoModRef) { |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 142 | if (!start && !block) { |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 143 | cachedResult.first = QI; |
| 144 | cachedResult.second = true; |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 145 | reverseDep[QI].insert(C.getInstruction()); |
| 146 | } |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 147 | return QI; |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | // No dependence found |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 152 | cachedResult.first = NonLocal; |
| 153 | cachedResult.second = true; |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 154 | reverseDep[NonLocal].insert(C.getInstruction()); |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 155 | return NonLocal; |
| 156 | } |
| 157 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 158 | /// nonLocalHelper - Private helper used to calculate non-local dependencies |
| 159 | /// by doing DFS on the predecessors of a block to find its dependencies |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 160 | void MemoryDependenceAnalysis::nonLocalHelper(Instruction* query, |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 161 | BasicBlock* block, |
Owen Anderson | 80b1f09 | 2007-08-08 22:01:54 +0000 | [diff] [blame] | 162 | DenseMap<BasicBlock*, Value*>& resp) { |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 163 | // Set of blocks that we've already visited in our DFS |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 164 | SmallPtrSet<BasicBlock*, 4> visited; |
Owen Anderson | ce4d88a | 2007-09-21 03:53:52 +0000 | [diff] [blame] | 165 | // If we're updating a dirtied cache entry, we don't need to reprocess |
| 166 | // already computed entries. |
| 167 | for (DenseMap<BasicBlock*, Value*>::iterator I = resp.begin(), |
| 168 | E = resp.end(); I != E; ++I) |
| 169 | if (I->second != Dirty) |
| 170 | visited.insert(I->first); |
| 171 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 172 | // Current stack of the DFS |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 173 | SmallVector<BasicBlock*, 4> stack; |
| 174 | stack.push_back(block); |
Owen Anderson | 4beedbd | 2007-07-24 21:52:37 +0000 | [diff] [blame] | 175 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 176 | // Do a basic DFS |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 177 | while (!stack.empty()) { |
| 178 | BasicBlock* BB = stack.back(); |
| 179 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 180 | // If we've already visited this block, no need to revist |
Owen Anderson | 1c2763d | 2007-08-02 17:56:05 +0000 | [diff] [blame] | 181 | if (visited.count(BB)) { |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 182 | stack.pop_back(); |
| 183 | continue; |
| 184 | } |
| 185 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 186 | // If we find a new block with a local dependency for query, |
| 187 | // then we insert the new dependency and backtrack. |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 188 | if (BB != block) { |
Owen Anderson | 1c2763d | 2007-08-02 17:56:05 +0000 | [diff] [blame] | 189 | visited.insert(BB); |
| 190 | |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 191 | Instruction* localDep = getDependency(query, 0, BB); |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 192 | if (localDep != NonLocal) { |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 193 | resp.insert(std::make_pair(BB, localDep)); |
Owen Anderson | 1c2763d | 2007-08-02 17:56:05 +0000 | [diff] [blame] | 194 | stack.pop_back(); |
| 195 | |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 196 | continue; |
| 197 | } |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 198 | // If we re-encounter the starting block, we still need to search it |
| 199 | // because there might be a dependency in the starting block AFTER |
| 200 | // the position of the query. This is necessary to get loops right. |
Owen Anderson | 1c2763d | 2007-08-02 17:56:05 +0000 | [diff] [blame] | 201 | } else if (BB == block && stack.size() > 1) { |
| 202 | visited.insert(BB); |
| 203 | |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 204 | Instruction* localDep = getDependency(query, 0, BB); |
Owen Anderson | 1c2763d | 2007-08-02 17:56:05 +0000 | [diff] [blame] | 205 | if (localDep != query) |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 206 | resp.insert(std::make_pair(BB, localDep)); |
Owen Anderson | 1c2763d | 2007-08-02 17:56:05 +0000 | [diff] [blame] | 207 | |
| 208 | stack.pop_back(); |
| 209 | |
| 210 | continue; |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 211 | } |
| 212 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 213 | // If we didn't find anything, recurse on the precessors of this block |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 214 | bool predOnStack = false; |
| 215 | bool inserted = false; |
| 216 | for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); |
| 217 | PI != PE; ++PI) |
| 218 | if (!visited.count(*PI)) { |
| 219 | stack.push_back(*PI); |
| 220 | inserted = true; |
| 221 | } else |
| 222 | predOnStack = true; |
| 223 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 224 | // If we inserted a new predecessor, then we'll come back to this block |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 225 | if (inserted) |
| 226 | continue; |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 227 | // If we didn't insert because we have no predecessors, then this |
| 228 | // query has no dependency at all. |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 229 | else if (!inserted && !predOnStack) { |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 230 | resp.insert(std::make_pair(BB, None)); |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 231 | // If we didn't insert because our predecessors are already on the stack, |
| 232 | // then we might still have a dependency, but it will be discovered during |
| 233 | // backtracking. |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 234 | } else if (!inserted && predOnStack){ |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 235 | resp.insert(std::make_pair(BB, NonLocal)); |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 236 | } |
| 237 | |
| 238 | stack.pop_back(); |
Owen Anderson | 4beedbd | 2007-07-24 21:52:37 +0000 | [diff] [blame] | 239 | } |
Owen Anderson | 4beedbd | 2007-07-24 21:52:37 +0000 | [diff] [blame] | 240 | } |
| 241 | |
Owen Anderson | 80b1f09 | 2007-08-08 22:01:54 +0000 | [diff] [blame] | 242 | /// getNonLocalDependency - Fills the passed-in map with the non-local |
| 243 | /// dependencies of the queries. The map will contain NonLocal for |
| 244 | /// blocks between the query and its dependencies. |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 245 | void MemoryDependenceAnalysis::getNonLocalDependency(Instruction* query, |
Owen Anderson | 80b1f09 | 2007-08-08 22:01:54 +0000 | [diff] [blame] | 246 | DenseMap<BasicBlock*, Value*>& resp) { |
Owen Anderson | 4d13de4 | 2007-08-16 21:27:05 +0000 | [diff] [blame] | 247 | if (depGraphNonLocal.count(query)) { |
Owen Anderson | ce4d88a | 2007-09-21 03:53:52 +0000 | [diff] [blame] | 248 | DenseMap<BasicBlock*, Value*>& cached = depGraphNonLocal[query]; |
Owen Anderson | 7fad7e3 | 2007-09-09 21:43:49 +0000 | [diff] [blame] | 249 | NumCacheNonlocal++; |
Owen Anderson | ce4d88a | 2007-09-21 03:53:52 +0000 | [diff] [blame] | 250 | |
| 251 | SmallVector<BasicBlock*, 4> dirtied; |
| 252 | for (DenseMap<BasicBlock*, Value*>::iterator I = cached.begin(), |
| 253 | E = cached.end(); I != E; ++I) |
| 254 | if (I->second == Dirty) |
| 255 | dirtied.push_back(I->first); |
| 256 | |
| 257 | for (SmallVector<BasicBlock*, 4>::iterator I = dirtied.begin(), |
| 258 | E = dirtied.end(); I != E; ++I) { |
| 259 | Instruction* localDep = getDependency(query, 0, *I); |
| 260 | if (localDep != NonLocal) |
| 261 | cached[*I] = localDep; |
| 262 | else { |
| 263 | cached.erase(*I); |
| 264 | nonLocalHelper(query, *I, cached); |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | resp = cached; |
| 269 | |
Owen Anderson | 4d13de4 | 2007-08-16 21:27:05 +0000 | [diff] [blame] | 270 | return; |
Owen Anderson | 7fad7e3 | 2007-09-09 21:43:49 +0000 | [diff] [blame] | 271 | } else |
| 272 | NumUncacheNonlocal++; |
Owen Anderson | 4d13de4 | 2007-08-16 21:27:05 +0000 | [diff] [blame] | 273 | |
Owen Anderson | 7fad7e3 | 2007-09-09 21:43:49 +0000 | [diff] [blame] | 274 | // If not, go ahead and search for non-local deps. |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 275 | nonLocalHelper(query, query->getParent(), resp); |
Owen Anderson | 4d13de4 | 2007-08-16 21:27:05 +0000 | [diff] [blame] | 276 | |
| 277 | // Update the non-local dependency cache |
| 278 | for (DenseMap<BasicBlock*, Value*>::iterator I = resp.begin(), E = resp.end(); |
| 279 | I != E; ++I) { |
| 280 | depGraphNonLocal[query].insert(*I); |
| 281 | reverseDepNonLocal[I->second].insert(query); |
| 282 | } |
Owen Anderson | 4beedbd | 2007-07-24 21:52:37 +0000 | [diff] [blame] | 283 | } |
| 284 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 285 | /// getDependency - Return the instruction on which a memory operation |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 286 | /// depends. The local paramter indicates if the query should only |
| 287 | /// evaluate dependencies within the same basic block. |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 288 | Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query, |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 289 | Instruction* start, |
Owen Anderson | 4beedbd | 2007-07-24 21:52:37 +0000 | [diff] [blame] | 290 | BasicBlock* block) { |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 291 | // Start looking for dependencies with the queried inst |
| 292 | BasicBlock::iterator QI = query; |
| 293 | |
| 294 | // Check for a cached result |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 295 | std::pair<Instruction*, bool>& cachedResult = depGraphLocal[query]; |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 296 | // If we have a _confirmed_ cached entry, return it |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 297 | if (!block && !start) { |
| 298 | if (cachedResult.second) |
| 299 | return cachedResult.first; |
| 300 | else if (cachedResult.first && cachedResult.first != NonLocal) |
| 301 | // If we have an unconfirmed cached entry, we can start our search from there |
| 302 | QI = cachedResult.first; |
| 303 | } |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 304 | |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 305 | if (start) |
| 306 | QI = start; |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 307 | else if (!start && block) |
| 308 | QI = block->end(); |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 309 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 310 | AliasAnalysis& AA = getAnalysis<AliasAnalysis>(); |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 311 | TargetData& TD = getAnalysis<TargetData>(); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 312 | |
| 313 | // Get the pointer value for which dependence will be determined |
| 314 | Value* dependee = 0; |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 315 | uint64_t dependeeSize = 0; |
Owen Anderson | e314eb3 | 2007-07-10 18:11:42 +0000 | [diff] [blame] | 316 | bool queryIsVolatile = false; |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 317 | if (StoreInst* S = dyn_cast<StoreInst>(query)) { |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 318 | dependee = S->getPointerOperand(); |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 319 | dependeeSize = TD.getTypeStoreSize(S->getOperand(0)->getType()); |
Owen Anderson | e314eb3 | 2007-07-10 18:11:42 +0000 | [diff] [blame] | 320 | queryIsVolatile = S->isVolatile(); |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 321 | } else if (LoadInst* L = dyn_cast<LoadInst>(query)) { |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 322 | dependee = L->getPointerOperand(); |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 323 | dependeeSize = TD.getTypeStoreSize(L->getType()); |
Owen Anderson | e314eb3 | 2007-07-10 18:11:42 +0000 | [diff] [blame] | 324 | queryIsVolatile = L->isVolatile(); |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 325 | } else if (VAArgInst* V = dyn_cast<VAArgInst>(query)) { |
Owen Anderson | 06b6e82 | 2007-07-10 18:43:15 +0000 | [diff] [blame] | 326 | dependee = V->getOperand(0); |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 327 | dependeeSize = TD.getTypeStoreSize(V->getType()); |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 328 | } else if (FreeInst* F = dyn_cast<FreeInst>(query)) { |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 329 | dependee = F->getPointerOperand(); |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 330 | |
| 331 | // FreeInsts erase the entire structure, not just a field |
| 332 | dependeeSize = ~0UL; |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 333 | } else if (CallSite::get(query).getInstruction() != 0) |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 334 | return getCallSiteDependency(CallSite::get(query), start, block); |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 335 | else if (isa<AllocationInst>(query)) |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 336 | return None; |
Owen Anderson | 7a616a1 | 2007-07-10 17:25:03 +0000 | [diff] [blame] | 337 | else |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 338 | return None; |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 339 | |
Owen Anderson | 4beedbd | 2007-07-24 21:52:37 +0000 | [diff] [blame] | 340 | BasicBlock::iterator blockBegin = block ? block->begin() |
| 341 | : query->getParent()->begin(); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 342 | |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 343 | // Walk backwards through the basic block, looking for dependencies |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 344 | while (QI != blockBegin) { |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 345 | --QI; |
| 346 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 347 | // If this inst is a memory op, get the pointer it accessed |
| 348 | Value* pointer = 0; |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 349 | uint64_t pointerSize = 0; |
| 350 | if (StoreInst* S = dyn_cast<StoreInst>(QI)) { |
Owen Anderson | e314eb3 | 2007-07-10 18:11:42 +0000 | [diff] [blame] | 351 | // All volatile loads/stores depend on each other |
| 352 | if (queryIsVolatile && S->isVolatile()) { |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 353 | if (!start && !block) { |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 354 | cachedResult.first = S; |
| 355 | cachedResult.second = true; |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 356 | reverseDep[S].insert(query); |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 357 | } |
| 358 | |
Owen Anderson | e314eb3 | 2007-07-10 18:11:42 +0000 | [diff] [blame] | 359 | return S; |
| 360 | } |
| 361 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 362 | pointer = S->getPointerOperand(); |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 363 | pointerSize = TD.getTypeStoreSize(S->getOperand(0)->getType()); |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 364 | } else if (LoadInst* L = dyn_cast<LoadInst>(QI)) { |
Owen Anderson | e314eb3 | 2007-07-10 18:11:42 +0000 | [diff] [blame] | 365 | // All volatile loads/stores depend on each other |
| 366 | if (queryIsVolatile && L->isVolatile()) { |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 367 | if (!start && !block) { |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 368 | cachedResult.first = L; |
| 369 | cachedResult.second = true; |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 370 | reverseDep[L].insert(query); |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 371 | } |
| 372 | |
Owen Anderson | e314eb3 | 2007-07-10 18:11:42 +0000 | [diff] [blame] | 373 | return L; |
| 374 | } |
| 375 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 376 | pointer = L->getPointerOperand(); |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 377 | pointerSize = TD.getTypeStoreSize(L->getType()); |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 378 | } else if (AllocationInst* AI = dyn_cast<AllocationInst>(QI)) { |
| 379 | pointer = AI; |
Owen Anderson | 7a616a1 | 2007-07-10 17:25:03 +0000 | [diff] [blame] | 380 | if (ConstantInt* C = dyn_cast<ConstantInt>(AI->getArraySize())) |
Owen Anderson | 80b1f09 | 2007-08-08 22:01:54 +0000 | [diff] [blame] | 381 | pointerSize = C->getZExtValue() * \ |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 382 | TD.getABITypeSize(AI->getAllocatedType()); |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 383 | else |
| 384 | pointerSize = ~0UL; |
Owen Anderson | 06b6e82 | 2007-07-10 18:43:15 +0000 | [diff] [blame] | 385 | } else if (VAArgInst* V = dyn_cast<VAArgInst>(QI)) { |
| 386 | pointer = V->getOperand(0); |
Duncan Sands | 514ab34 | 2007-11-01 20:53:16 +0000 | [diff] [blame] | 387 | pointerSize = TD.getTypeStoreSize(V->getType()); |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 388 | } else if (FreeInst* F = dyn_cast<FreeInst>(QI)) { |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 389 | pointer = F->getPointerOperand(); |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 390 | |
| 391 | // FreeInsts erase the entire structure |
| 392 | pointerSize = ~0UL; |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 393 | } else if (CallSite::get(QI).getInstruction() != 0) { |
Owen Anderson | 80b1f09 | 2007-08-08 22:01:54 +0000 | [diff] [blame] | 394 | // Call insts need special handling. Check if they can modify our pointer |
Owen Anderson | 8f35315 | 2007-08-06 23:26:03 +0000 | [diff] [blame] | 395 | AliasAnalysis::ModRefResult MR = AA.getModRefInfo(CallSite::get(QI), |
| 396 | dependee, dependeeSize); |
| 397 | |
| 398 | if (MR != AliasAnalysis::NoModRef) { |
| 399 | // Loads don't depend on read-only calls |
| 400 | if (isa<LoadInst>(query) && MR == AliasAnalysis::Ref) |
| 401 | continue; |
| 402 | |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 403 | if (!start && !block) { |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 404 | cachedResult.first = QI; |
| 405 | cachedResult.second = true; |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 406 | reverseDep[QI].insert(query); |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 407 | } |
| 408 | |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 409 | return QI; |
Owen Anderson | 7a616a1 | 2007-07-10 17:25:03 +0000 | [diff] [blame] | 410 | } else { |
| 411 | continue; |
| 412 | } |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 413 | } |
| 414 | |
| 415 | // If we found a pointer, check if it could be the same as our pointer |
| 416 | if (pointer) { |
Owen Anderson | 6b278fc | 2007-07-10 17:08:11 +0000 | [diff] [blame] | 417 | AliasAnalysis::AliasResult R = AA.alias(pointer, pointerSize, |
| 418 | dependee, dependeeSize); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 419 | |
| 420 | if (R != AliasAnalysis::NoAlias) { |
Owen Anderson | 8f35315 | 2007-08-06 23:26:03 +0000 | [diff] [blame] | 421 | // May-alias loads don't depend on each other |
| 422 | if (isa<LoadInst>(query) && isa<LoadInst>(QI) && |
| 423 | R == AliasAnalysis::MayAlias) |
| 424 | continue; |
| 425 | |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 426 | if (!start && !block) { |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 427 | cachedResult.first = QI; |
| 428 | cachedResult.second = true; |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 429 | reverseDep[QI].insert(query); |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 430 | } |
| 431 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 432 | return QI; |
| 433 | } |
| 434 | } |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 435 | } |
| 436 | |
| 437 | // If we found nothing, return the non-local flag |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 438 | if (!start && !block) { |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 439 | cachedResult.first = NonLocal; |
| 440 | cachedResult.second = true; |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 441 | reverseDep[NonLocal].insert(query); |
Owen Anderson | faac518 | 2007-07-16 21:52:50 +0000 | [diff] [blame] | 442 | } |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 443 | |
| 444 | return NonLocal; |
| 445 | } |
| 446 | |
| 447 | /// removeInstruction - Remove an instruction from the dependence analysis, |
| 448 | /// updating the dependence of instructions that previously depended on it. |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 449 | /// This method attempts to keep the cache coherent using the reverse map. |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 450 | void MemoryDependenceAnalysis::removeInstruction(Instruction* rem) { |
| 451 | // Figure out the new dep for things that currently depend on rem |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 452 | Instruction* newDep = NonLocal; |
David Greene | df46419 | 2007-07-31 20:01:27 +0000 | [diff] [blame] | 453 | |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 454 | reverseDep[depGraphLocal[rem].first].erase(rem); |
| 455 | |
| 456 | for (DenseMap<BasicBlock*, Value*>::iterator DI = |
| 457 | depGraphNonLocal[rem].begin(), DE = depGraphNonLocal[rem].end(); |
| 458 | DI != DE; ++DI) |
| 459 | if (DI->second != None) |
| 460 | reverseDepNonLocal[DI->second].erase(rem); |
| 461 | |
David Greene | df46419 | 2007-07-31 20:01:27 +0000 | [diff] [blame] | 462 | depMapType::iterator depGraphEntry = depGraphLocal.find(rem); |
David Greene | df46419 | 2007-07-31 20:01:27 +0000 | [diff] [blame] | 463 | |
| 464 | if (depGraphEntry != depGraphLocal.end()) { |
| 465 | if (depGraphEntry->second.first != NonLocal && |
| 466 | depGraphEntry->second.second) { |
| 467 | // If we have dep info for rem, set them to it |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 468 | BasicBlock::iterator RI = depGraphEntry->second.first; |
David Greene | df46419 | 2007-07-31 20:01:27 +0000 | [diff] [blame] | 469 | RI++; |
| 470 | newDep = RI; |
| 471 | } else if (depGraphEntry->second.first == NonLocal && |
| 472 | depGraphEntry->second.second ) { |
| 473 | // If we have a confirmed non-local flag, use it |
| 474 | newDep = NonLocal; |
| 475 | } else { |
| 476 | // Otherwise, use the immediate successor of rem |
Owen Anderson | 80b1f09 | 2007-08-08 22:01:54 +0000 | [diff] [blame] | 477 | // NOTE: This is because, when getDependence is called, it will first |
| 478 | // check the immediate predecessor of what is in the cache. |
David Greene | df46419 | 2007-07-31 20:01:27 +0000 | [diff] [blame] | 479 | BasicBlock::iterator RI = rem; |
| 480 | RI++; |
| 481 | newDep = RI; |
| 482 | } |
| 483 | |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 484 | SmallPtrSet<Instruction*, 4>& set = reverseDep[rem]; |
| 485 | for (SmallPtrSet<Instruction*, 4>::iterator I = set.begin(), E = set.end(); |
| 486 | I != E; ++I) { |
David Greene | df46419 | 2007-07-31 20:01:27 +0000 | [diff] [blame] | 487 | // Insert the new dependencies |
| 488 | // Mark it as unconfirmed as long as it is not the non-local flag |
Owen Anderson | dbbe816 | 2007-08-07 00:33:45 +0000 | [diff] [blame] | 489 | depGraphLocal[*I] = std::make_pair(newDep, !newDep); |
David Greene | df46419 | 2007-07-31 20:01:27 +0000 | [diff] [blame] | 490 | } |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 491 | } |
Owen Anderson | 4d13de4 | 2007-08-16 21:27:05 +0000 | [diff] [blame] | 492 | |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 493 | depGraphLocal.erase(rem); |
| 494 | reverseDep.erase(rem); |
| 495 | |
Owen Anderson | 0a890e2 | 2007-09-11 04:31:00 +0000 | [diff] [blame] | 496 | if (reverseDepNonLocal.count(rem)) { |
Owen Anderson | 4d13de4 | 2007-08-16 21:27:05 +0000 | [diff] [blame] | 497 | SmallPtrSet<Instruction*, 4>& set = reverseDepNonLocal[rem]; |
| 498 | for (SmallPtrSet<Instruction*, 4>::iterator I = set.begin(), E = set.end(); |
| 499 | I != E; ++I) |
Owen Anderson | ce4d88a | 2007-09-21 03:53:52 +0000 | [diff] [blame] | 500 | for (DenseMap<BasicBlock*, Value*>::iterator DI = |
| 501 | depGraphNonLocal[*I].begin(), DE = depGraphNonLocal[*I].end(); |
| 502 | DI != DE; ++DI) |
| 503 | if (DI->second == rem) |
| 504 | DI->second = Dirty; |
Owen Anderson | 4d13de4 | 2007-08-16 21:27:05 +0000 | [diff] [blame] | 505 | |
Owen Anderson | 4d13de4 | 2007-08-16 21:27:05 +0000 | [diff] [blame] | 506 | } |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 507 | |
| 508 | reverseDepNonLocal.erase(rem); |
| 509 | nonLocalDepMapType::iterator I = depGraphNonLocal.find(rem); |
| 510 | if (I != depGraphNonLocal.end()) |
| 511 | depGraphNonLocal.erase(I); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 512 | |
Owen Anderson | 1cb960a | 2007-07-12 00:06:21 +0000 | [diff] [blame] | 513 | getAnalysis<AliasAnalysis>().deleteValue(rem); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 514 | } |