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 | |
Chris Lattner | 0e575f4 | 2008-11-28 21:45:17 +0000 | [diff] [blame] | 17 | #define DEBUG_TYPE "memdep" |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 18 | #include "llvm/Analysis/MemoryDependenceAnalysis.h" |
Owen Anderson | 7a616a1 | 2007-07-10 17:25:03 +0000 | [diff] [blame] | 19 | #include "llvm/Constants.h" |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 20 | #include "llvm/Instructions.h" |
| 21 | #include "llvm/Function.h" |
| 22 | #include "llvm/Analysis/AliasAnalysis.h" |
Chris Lattner | baad888 | 2008-11-28 22:28:27 +0000 | [diff] [blame] | 23 | #include "llvm/ADT/Statistic.h" |
Duncan Sands | 7050f3d | 2008-12-10 09:38:36 +0000 | [diff] [blame] | 24 | #include "llvm/ADT/STLExtras.h" |
Chris Lattner | 4012fdd | 2008-12-09 06:28:49 +0000 | [diff] [blame] | 25 | #include "llvm/Support/PredIteratorCache.h" |
Chris Lattner | 0e575f4 | 2008-11-28 21:45:17 +0000 | [diff] [blame] | 26 | #include "llvm/Support/Debug.h" |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 27 | #include "llvm/Target/TargetData.h" |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 28 | using namespace llvm; |
| 29 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 30 | STATISTIC(NumCacheNonLocal, "Number of fully cached non-local responses"); |
| 31 | STATISTIC(NumCacheDirtyNonLocal, "Number of dirty cached non-local responses"); |
Chris Lattner | 0ec48dd | 2008-11-29 22:02:15 +0000 | [diff] [blame] | 32 | STATISTIC(NumUncacheNonLocal, "Number of uncached non-local responses"); |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 33 | |
| 34 | STATISTIC(NumCacheNonLocalPtr, |
| 35 | "Number of fully cached non-local ptr responses"); |
| 36 | STATISTIC(NumCacheDirtyNonLocalPtr, |
| 37 | "Number of cached, but dirty, non-local ptr responses"); |
| 38 | STATISTIC(NumUncacheNonLocalPtr, |
| 39 | "Number of uncached non-local ptr responses"); |
Chris Lattner | 11dcd8d | 2008-12-08 07:31:50 +0000 | [diff] [blame] | 40 | STATISTIC(NumCacheCompleteNonLocalPtr, |
| 41 | "Number of block queries that were completely cached"); |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 42 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 43 | char MemoryDependenceAnalysis::ID = 0; |
| 44 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 45 | // Register this pass... |
Owen Anderson | 776ee1f | 2007-07-10 20:21:08 +0000 | [diff] [blame] | 46 | static RegisterPass<MemoryDependenceAnalysis> X("memdep", |
Chris Lattner | 0e575f4 | 2008-11-28 21:45:17 +0000 | [diff] [blame] | 47 | "Memory Dependence Analysis", false, true); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 48 | |
Chris Lattner | 4012fdd | 2008-12-09 06:28:49 +0000 | [diff] [blame] | 49 | MemoryDependenceAnalysis::MemoryDependenceAnalysis() |
| 50 | : FunctionPass(&ID), PredCache(0) { |
| 51 | } |
| 52 | MemoryDependenceAnalysis::~MemoryDependenceAnalysis() { |
| 53 | } |
| 54 | |
| 55 | /// Clean up memory in between runs |
| 56 | void MemoryDependenceAnalysis::releaseMemory() { |
| 57 | LocalDeps.clear(); |
| 58 | NonLocalDeps.clear(); |
| 59 | NonLocalPointerDeps.clear(); |
| 60 | ReverseLocalDeps.clear(); |
| 61 | ReverseNonLocalDeps.clear(); |
| 62 | ReverseNonLocalPtrDeps.clear(); |
| 63 | PredCache->clear(); |
| 64 | } |
| 65 | |
| 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 | |
Chris Lattner | d777d40 | 2008-11-30 19:24:31 +0000 | [diff] [blame] | 76 | bool MemoryDependenceAnalysis::runOnFunction(Function &) { |
| 77 | AA = &getAnalysis<AliasAnalysis>(); |
| 78 | TD = &getAnalysis<TargetData>(); |
Chris Lattner | 4012fdd | 2008-12-09 06:28:49 +0000 | [diff] [blame] | 79 | if (PredCache == 0) |
| 80 | PredCache.reset(new PredIteratorCache()); |
Chris Lattner | d777d40 | 2008-11-30 19:24:31 +0000 | [diff] [blame] | 81 | return false; |
| 82 | } |
| 83 | |
Chris Lattner | d44745d | 2008-12-07 18:39:13 +0000 | [diff] [blame] | 84 | /// RemoveFromReverseMap - This is a helper function that removes Val from |
| 85 | /// 'Inst's set in ReverseMap. If the set becomes empty, remove Inst's entry. |
| 86 | template <typename KeyTy> |
| 87 | static void RemoveFromReverseMap(DenseMap<Instruction*, |
| 88 | SmallPtrSet<KeyTy*, 4> > &ReverseMap, |
| 89 | Instruction *Inst, KeyTy *Val) { |
| 90 | typename DenseMap<Instruction*, SmallPtrSet<KeyTy*, 4> >::iterator |
| 91 | InstIt = ReverseMap.find(Inst); |
| 92 | assert(InstIt != ReverseMap.end() && "Reverse map out of sync?"); |
| 93 | bool Found = InstIt->second.erase(Val); |
| 94 | assert(Found && "Invalid reverse map!"); Found=Found; |
| 95 | if (InstIt->second.empty()) |
| 96 | ReverseMap.erase(InstIt); |
| 97 | } |
| 98 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 99 | |
Chris Lattner | 8ef57c5 | 2008-12-07 00:35:51 +0000 | [diff] [blame] | 100 | /// getCallSiteDependencyFrom - Private helper for finding the local |
| 101 | /// dependencies of a call site. |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 102 | MemDepResult MemoryDependenceAnalysis:: |
Chris Lattner | 20d6f09 | 2008-12-09 21:19:42 +0000 | [diff] [blame] | 103 | getCallSiteDependencyFrom(CallSite CS, bool isReadOnlyCall, |
| 104 | BasicBlock::iterator ScanIt, BasicBlock *BB) { |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 105 | // Walk backwards through the block, looking for dependencies |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 106 | while (ScanIt != BB->begin()) { |
| 107 | Instruction *Inst = --ScanIt; |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 108 | |
| 109 | // If this inst is a memory op, get the pointer it accessed |
Chris Lattner | 00314b3 | 2008-11-29 09:15:21 +0000 | [diff] [blame] | 110 | Value *Pointer = 0; |
| 111 | uint64_t PointerSize = 0; |
| 112 | if (StoreInst *S = dyn_cast<StoreInst>(Inst)) { |
| 113 | Pointer = S->getPointerOperand(); |
Chris Lattner | d777d40 | 2008-11-30 19:24:31 +0000 | [diff] [blame] | 114 | PointerSize = TD->getTypeStoreSize(S->getOperand(0)->getType()); |
Chris Lattner | 00314b3 | 2008-11-29 09:15:21 +0000 | [diff] [blame] | 115 | } else if (VAArgInst *V = dyn_cast<VAArgInst>(Inst)) { |
| 116 | Pointer = V->getOperand(0); |
Chris Lattner | d777d40 | 2008-11-30 19:24:31 +0000 | [diff] [blame] | 117 | PointerSize = TD->getTypeStoreSize(V->getType()); |
Chris Lattner | 00314b3 | 2008-11-29 09:15:21 +0000 | [diff] [blame] | 118 | } else if (FreeInst *F = dyn_cast<FreeInst>(Inst)) { |
| 119 | Pointer = F->getPointerOperand(); |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 120 | |
| 121 | // FreeInsts erase the entire structure |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 122 | PointerSize = ~0ULL; |
Chris Lattner | 00314b3 | 2008-11-29 09:15:21 +0000 | [diff] [blame] | 123 | } else if (isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) { |
Chris Lattner | b51deb9 | 2008-12-05 21:04:20 +0000 | [diff] [blame] | 124 | CallSite InstCS = CallSite::get(Inst); |
| 125 | // If these two calls do not interfere, look past it. |
Chris Lattner | 20d6f09 | 2008-12-09 21:19:42 +0000 | [diff] [blame] | 126 | switch (AA->getModRefInfo(CS, InstCS)) { |
| 127 | case AliasAnalysis::NoModRef: |
| 128 | // If the two calls don't interact (e.g. InstCS is readnone) keep |
| 129 | // scanning. |
Chris Lattner | 00314b3 | 2008-11-29 09:15:21 +0000 | [diff] [blame] | 130 | continue; |
Chris Lattner | 20d6f09 | 2008-12-09 21:19:42 +0000 | [diff] [blame] | 131 | case AliasAnalysis::Ref: |
| 132 | // If the two calls read the same memory locations and CS is a readonly |
| 133 | // function, then we have two cases: 1) the calls may not interfere with |
| 134 | // each other at all. 2) the calls may produce the same value. In case |
| 135 | // #1 we want to ignore the values, in case #2, we want to return Inst |
| 136 | // as a Def dependence. This allows us to CSE in cases like: |
| 137 | // X = strlen(P); |
| 138 | // memchr(...); |
| 139 | // Y = strlen(P); // Y = X |
| 140 | if (isReadOnlyCall) { |
| 141 | if (CS.getCalledFunction() != 0 && |
| 142 | CS.getCalledFunction() == InstCS.getCalledFunction()) |
| 143 | return MemDepResult::getDef(Inst); |
| 144 | // Ignore unrelated read/read call dependences. |
| 145 | continue; |
| 146 | } |
| 147 | // FALL THROUGH |
| 148 | default: |
Chris Lattner | b51deb9 | 2008-12-05 21:04:20 +0000 | [diff] [blame] | 149 | return MemDepResult::getClobber(Inst); |
Chris Lattner | 20d6f09 | 2008-12-09 21:19:42 +0000 | [diff] [blame] | 150 | } |
Chris Lattner | cfbb634 | 2008-11-30 01:44:00 +0000 | [diff] [blame] | 151 | } else { |
| 152 | // Non-memory instruction. |
Owen Anderson | 202da14 | 2007-07-10 20:39:07 +0000 | [diff] [blame] | 153 | continue; |
Chris Lattner | cfbb634 | 2008-11-30 01:44:00 +0000 | [diff] [blame] | 154 | } |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 155 | |
Chris Lattner | b51deb9 | 2008-12-05 21:04:20 +0000 | [diff] [blame] | 156 | if (AA->getModRefInfo(CS, Pointer, PointerSize) != AliasAnalysis::NoModRef) |
| 157 | return MemDepResult::getClobber(Inst); |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 158 | } |
| 159 | |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 160 | // No dependence found. If this is the entry block of the function, it is a |
| 161 | // clobber, otherwise it is non-local. |
| 162 | if (BB != &BB->getParent()->getEntryBlock()) |
| 163 | return MemDepResult::getNonLocal(); |
| 164 | return MemDepResult::getClobber(ScanIt); |
Owen Anderson | 5f32320 | 2007-07-10 17:59:22 +0000 | [diff] [blame] | 165 | } |
| 166 | |
Chris Lattner | e79be94 | 2008-12-07 01:50:16 +0000 | [diff] [blame] | 167 | /// getPointerDependencyFrom - Return the instruction on which a memory |
| 168 | /// location depends. If isLoad is true, this routine ignore may-aliases with |
| 169 | /// read-only operations. |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 170 | MemDepResult MemoryDependenceAnalysis:: |
Chris Lattner | e79be94 | 2008-12-07 01:50:16 +0000 | [diff] [blame] | 171 | getPointerDependencyFrom(Value *MemPtr, uint64_t MemSize, bool isLoad, |
| 172 | BasicBlock::iterator ScanIt, BasicBlock *BB) { |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 173 | |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 174 | // Walk backwards through the basic block, looking for dependencies. |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 175 | while (ScanIt != BB->begin()) { |
| 176 | Instruction *Inst = --ScanIt; |
Chris Lattner | a161ab0 | 2008-11-29 09:09:48 +0000 | [diff] [blame] | 177 | |
Chris Lattner | cfbb634 | 2008-11-30 01:44:00 +0000 | [diff] [blame] | 178 | // Values depend on loads if the pointers are must aliased. This means that |
| 179 | // a load depends on another must aliased load from the same value. |
Chris Lattner | b51deb9 | 2008-12-05 21:04:20 +0000 | [diff] [blame] | 180 | if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) { |
Chris Lattner | b51deb9 | 2008-12-05 21:04:20 +0000 | [diff] [blame] | 181 | Value *Pointer = LI->getPointerOperand(); |
| 182 | uint64_t PointerSize = TD->getTypeStoreSize(LI->getType()); |
| 183 | |
| 184 | // If we found a pointer, check if it could be the same as our pointer. |
Chris Lattner | a161ab0 | 2008-11-29 09:09:48 +0000 | [diff] [blame] | 185 | AliasAnalysis::AliasResult R = |
Chris Lattner | d777d40 | 2008-11-30 19:24:31 +0000 | [diff] [blame] | 186 | AA->alias(Pointer, PointerSize, MemPtr, MemSize); |
Chris Lattner | a161ab0 | 2008-11-29 09:09:48 +0000 | [diff] [blame] | 187 | if (R == AliasAnalysis::NoAlias) |
| 188 | continue; |
| 189 | |
| 190 | // May-alias loads don't depend on each other without a dependence. |
Chris Lattner | e79be94 | 2008-12-07 01:50:16 +0000 | [diff] [blame] | 191 | if (isLoad && R == AliasAnalysis::MayAlias) |
Chris Lattner | a161ab0 | 2008-11-29 09:09:48 +0000 | [diff] [blame] | 192 | continue; |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 193 | // Stores depend on may and must aliased loads, loads depend on must-alias |
| 194 | // loads. |
Chris Lattner | b51deb9 | 2008-12-05 21:04:20 +0000 | [diff] [blame] | 195 | return MemDepResult::getDef(Inst); |
| 196 | } |
| 197 | |
| 198 | if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) { |
Chris Lattner | b51deb9 | 2008-12-05 21:04:20 +0000 | [diff] [blame] | 199 | Value *Pointer = SI->getPointerOperand(); |
| 200 | uint64_t PointerSize = TD->getTypeStoreSize(SI->getOperand(0)->getType()); |
| 201 | |
| 202 | // If we found a pointer, check if it could be the same as our pointer. |
| 203 | AliasAnalysis::AliasResult R = |
| 204 | AA->alias(Pointer, PointerSize, MemPtr, MemSize); |
| 205 | |
| 206 | if (R == AliasAnalysis::NoAlias) |
| 207 | continue; |
| 208 | if (R == AliasAnalysis::MayAlias) |
| 209 | return MemDepResult::getClobber(Inst); |
| 210 | return MemDepResult::getDef(Inst); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 211 | } |
Chris Lattner | 237a828 | 2008-11-30 01:39:32 +0000 | [diff] [blame] | 212 | |
| 213 | // If this is an allocation, and if we know that the accessed pointer is to |
Chris Lattner | b51deb9 | 2008-12-05 21:04:20 +0000 | [diff] [blame] | 214 | // the allocation, return Def. This means that there is no dependence and |
Chris Lattner | 237a828 | 2008-11-30 01:39:32 +0000 | [diff] [blame] | 215 | // the access can be optimized based on that. For example, a load could |
| 216 | // turn into undef. |
Chris Lattner | a161ab0 | 2008-11-29 09:09:48 +0000 | [diff] [blame] | 217 | if (AllocationInst *AI = dyn_cast<AllocationInst>(Inst)) { |
Chris Lattner | 237a828 | 2008-11-30 01:39:32 +0000 | [diff] [blame] | 218 | Value *AccessPtr = MemPtr->getUnderlyingObject(); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 219 | |
Chris Lattner | 237a828 | 2008-11-30 01:39:32 +0000 | [diff] [blame] | 220 | if (AccessPtr == AI || |
Chris Lattner | d777d40 | 2008-11-30 19:24:31 +0000 | [diff] [blame] | 221 | AA->alias(AI, 1, AccessPtr, 1) == AliasAnalysis::MustAlias) |
Chris Lattner | b51deb9 | 2008-12-05 21:04:20 +0000 | [diff] [blame] | 222 | return MemDepResult::getDef(AI); |
Chris Lattner | 237a828 | 2008-11-30 01:39:32 +0000 | [diff] [blame] | 223 | continue; |
Chris Lattner | a161ab0 | 2008-11-29 09:09:48 +0000 | [diff] [blame] | 224 | } |
Chris Lattner | a161ab0 | 2008-11-29 09:09:48 +0000 | [diff] [blame] | 225 | |
Chris Lattner | b51deb9 | 2008-12-05 21:04:20 +0000 | [diff] [blame] | 226 | // See if this instruction (e.g. a call or vaarg) mod/ref's the pointer. |
Chris Lattner | 3579e44 | 2008-12-09 19:47:40 +0000 | [diff] [blame] | 227 | switch (AA->getModRefInfo(Inst, MemPtr, MemSize)) { |
| 228 | case AliasAnalysis::NoModRef: |
| 229 | // If the call has no effect on the queried pointer, just ignore it. |
Chris Lattner | 25a0814 | 2008-11-29 08:51:16 +0000 | [diff] [blame] | 230 | continue; |
Chris Lattner | 3579e44 | 2008-12-09 19:47:40 +0000 | [diff] [blame] | 231 | case AliasAnalysis::Ref: |
| 232 | // If the call is known to never store to the pointer, and if this is a |
| 233 | // load query, we can safely ignore it (scan past it). |
| 234 | if (isLoad) |
| 235 | continue; |
| 236 | // FALL THROUGH. |
| 237 | default: |
| 238 | // Otherwise, there is a potential dependence. Return a clobber. |
| 239 | return MemDepResult::getClobber(Inst); |
| 240 | } |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 241 | } |
| 242 | |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 243 | // No dependence found. If this is the entry block of the function, it is a |
| 244 | // clobber, otherwise it is non-local. |
| 245 | if (BB != &BB->getParent()->getEntryBlock()) |
| 246 | return MemDepResult::getNonLocal(); |
| 247 | return MemDepResult::getClobber(ScanIt); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 248 | } |
| 249 | |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 250 | /// getDependency - Return the instruction on which a memory operation |
| 251 | /// depends. |
| 252 | MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) { |
| 253 | Instruction *ScanPos = QueryInst; |
| 254 | |
| 255 | // Check for a cached result |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 256 | MemDepResult &LocalCache = LocalDeps[QueryInst]; |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 257 | |
Chris Lattner | 0ec48dd | 2008-11-29 22:02:15 +0000 | [diff] [blame] | 258 | // If the cached entry is non-dirty, just return it. Note that this depends |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 259 | // on MemDepResult's default constructing to 'dirty'. |
| 260 | if (!LocalCache.isDirty()) |
| 261 | return LocalCache; |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 262 | |
| 263 | // Otherwise, if we have a dirty entry, we know we can start the scan at that |
| 264 | // instruction, which may save us some work. |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 265 | if (Instruction *Inst = LocalCache.getInst()) { |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 266 | ScanPos = Inst; |
Chris Lattner | 4a69bad | 2008-11-30 02:52:26 +0000 | [diff] [blame] | 267 | |
Chris Lattner | d44745d | 2008-12-07 18:39:13 +0000 | [diff] [blame] | 268 | RemoveFromReverseMap(ReverseLocalDeps, Inst, QueryInst); |
Chris Lattner | 4a69bad | 2008-11-30 02:52:26 +0000 | [diff] [blame] | 269 | } |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 270 | |
Chris Lattner | e79be94 | 2008-12-07 01:50:16 +0000 | [diff] [blame] | 271 | BasicBlock *QueryParent = QueryInst->getParent(); |
| 272 | |
| 273 | Value *MemPtr = 0; |
| 274 | uint64_t MemSize = 0; |
| 275 | |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 276 | // Do the scan. |
Chris Lattner | e79be94 | 2008-12-07 01:50:16 +0000 | [diff] [blame] | 277 | if (BasicBlock::iterator(QueryInst) == QueryParent->begin()) { |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 278 | // No dependence found. If this is the entry block of the function, it is a |
| 279 | // clobber, otherwise it is non-local. |
| 280 | if (QueryParent != &QueryParent->getParent()->getEntryBlock()) |
| 281 | LocalCache = MemDepResult::getNonLocal(); |
| 282 | else |
| 283 | LocalCache = MemDepResult::getClobber(QueryInst); |
Chris Lattner | e79be94 | 2008-12-07 01:50:16 +0000 | [diff] [blame] | 284 | } else if (StoreInst *SI = dyn_cast<StoreInst>(QueryInst)) { |
| 285 | // If this is a volatile store, don't mess around with it. Just return the |
| 286 | // previous instruction as a clobber. |
| 287 | if (SI->isVolatile()) |
| 288 | LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos)); |
| 289 | else { |
| 290 | MemPtr = SI->getPointerOperand(); |
| 291 | MemSize = TD->getTypeStoreSize(SI->getOperand(0)->getType()); |
| 292 | } |
| 293 | } else if (LoadInst *LI = dyn_cast<LoadInst>(QueryInst)) { |
| 294 | // If this is a volatile load, don't mess around with it. Just return the |
| 295 | // previous instruction as a clobber. |
| 296 | if (LI->isVolatile()) |
| 297 | LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos)); |
| 298 | else { |
| 299 | MemPtr = LI->getPointerOperand(); |
| 300 | MemSize = TD->getTypeStoreSize(LI->getType()); |
| 301 | } |
| 302 | } else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) { |
Chris Lattner | 20d6f09 | 2008-12-09 21:19:42 +0000 | [diff] [blame] | 303 | CallSite QueryCS = CallSite::get(QueryInst); |
| 304 | bool isReadOnly = AA->onlyReadsMemory(QueryCS); |
| 305 | LocalCache = getCallSiteDependencyFrom(QueryCS, isReadOnly, ScanPos, |
Chris Lattner | e79be94 | 2008-12-07 01:50:16 +0000 | [diff] [blame] | 306 | QueryParent); |
| 307 | } else if (FreeInst *FI = dyn_cast<FreeInst>(QueryInst)) { |
| 308 | MemPtr = FI->getPointerOperand(); |
| 309 | // FreeInsts erase the entire structure, not just a field. |
| 310 | MemSize = ~0UL; |
| 311 | } else { |
| 312 | // Non-memory instruction. |
| 313 | LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos)); |
| 314 | } |
| 315 | |
| 316 | // If we need to do a pointer scan, make it happen. |
| 317 | if (MemPtr) |
| 318 | LocalCache = getPointerDependencyFrom(MemPtr, MemSize, |
| 319 | isa<LoadInst>(QueryInst), |
| 320 | ScanPos, QueryParent); |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 321 | |
| 322 | // Remember the result! |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 323 | if (Instruction *I = LocalCache.getInst()) |
Chris Lattner | 8c46527 | 2008-11-29 09:20:15 +0000 | [diff] [blame] | 324 | ReverseLocalDeps[I].insert(QueryInst); |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 325 | |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 326 | return LocalCache; |
Chris Lattner | 5391a1d | 2008-11-29 03:47:00 +0000 | [diff] [blame] | 327 | } |
| 328 | |
Chris Lattner | 1559b36 | 2008-12-09 19:38:05 +0000 | [diff] [blame] | 329 | /// getNonLocalCallDependency - Perform a full dependency query for the |
| 330 | /// specified call, returning the set of blocks that the value is |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 331 | /// potentially live across. The returned set of results will include a |
| 332 | /// "NonLocal" result for all blocks where the value is live across. |
| 333 | /// |
Chris Lattner | 1559b36 | 2008-12-09 19:38:05 +0000 | [diff] [blame] | 334 | /// This method assumes the instruction returns a "NonLocal" dependency |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 335 | /// within its own block. |
| 336 | /// |
Chris Lattner | 1559b36 | 2008-12-09 19:38:05 +0000 | [diff] [blame] | 337 | /// This returns a reference to an internal data structure that may be |
| 338 | /// invalidated on the next non-local query or when an instruction is |
| 339 | /// removed. Clients must copy this data if they want it around longer than |
| 340 | /// that. |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 341 | const MemoryDependenceAnalysis::NonLocalDepInfo & |
Chris Lattner | 1559b36 | 2008-12-09 19:38:05 +0000 | [diff] [blame] | 342 | MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) { |
| 343 | assert(getDependency(QueryCS.getInstruction()).isNonLocal() && |
| 344 | "getNonLocalCallDependency should only be used on calls with non-local deps!"); |
| 345 | PerInstNLInfo &CacheP = NonLocalDeps[QueryCS.getInstruction()]; |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 346 | NonLocalDepInfo &Cache = CacheP.first; |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 347 | |
| 348 | /// DirtyBlocks - This is the set of blocks that need to be recomputed. In |
| 349 | /// the cached case, this can happen due to instructions being deleted etc. In |
| 350 | /// the uncached case, this starts out as the set of predecessors we care |
| 351 | /// about. |
| 352 | SmallVector<BasicBlock*, 32> DirtyBlocks; |
| 353 | |
| 354 | if (!Cache.empty()) { |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 355 | // Okay, we have a cache entry. If we know it is not dirty, just return it |
| 356 | // with no computation. |
| 357 | if (!CacheP.second) { |
| 358 | NumCacheNonLocal++; |
| 359 | return Cache; |
| 360 | } |
| 361 | |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 362 | // If we already have a partially computed set of results, scan them to |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 363 | // determine what is dirty, seeding our initial DirtyBlocks worklist. |
| 364 | for (NonLocalDepInfo::iterator I = Cache.begin(), E = Cache.end(); |
| 365 | I != E; ++I) |
| 366 | if (I->second.isDirty()) |
| 367 | DirtyBlocks.push_back(I->first); |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 368 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 369 | // Sort the cache so that we can do fast binary search lookups below. |
| 370 | std::sort(Cache.begin(), Cache.end()); |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 371 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 372 | ++NumCacheDirtyNonLocal; |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 373 | //cerr << "CACHED CASE: " << DirtyBlocks.size() << " dirty: " |
| 374 | // << Cache.size() << " cached: " << *QueryInst; |
| 375 | } else { |
| 376 | // Seed DirtyBlocks with each of the preds of QueryInst's block. |
Chris Lattner | 1559b36 | 2008-12-09 19:38:05 +0000 | [diff] [blame] | 377 | BasicBlock *QueryBB = QueryCS.getInstruction()->getParent(); |
Chris Lattner | 511b36c | 2008-12-09 06:44:17 +0000 | [diff] [blame] | 378 | for (BasicBlock **PI = PredCache->GetPreds(QueryBB); *PI; ++PI) |
| 379 | DirtyBlocks.push_back(*PI); |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 380 | NumUncacheNonLocal++; |
| 381 | } |
| 382 | |
Chris Lattner | 20d6f09 | 2008-12-09 21:19:42 +0000 | [diff] [blame] | 383 | // isReadonlyCall - If this is a read-only call, we can be more aggressive. |
| 384 | bool isReadonlyCall = AA->onlyReadsMemory(QueryCS); |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 385 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 386 | SmallPtrSet<BasicBlock*, 64> Visited; |
| 387 | |
| 388 | unsigned NumSortedEntries = Cache.size(); |
| 389 | |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 390 | // Iterate while we still have blocks to update. |
| 391 | while (!DirtyBlocks.empty()) { |
| 392 | BasicBlock *DirtyBB = DirtyBlocks.back(); |
| 393 | DirtyBlocks.pop_back(); |
| 394 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 395 | // Already processed this block? |
| 396 | if (!Visited.insert(DirtyBB)) |
| 397 | continue; |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 398 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 399 | // Do a binary search to see if we already have an entry for this block in |
| 400 | // the cache set. If so, find it. |
| 401 | NonLocalDepInfo::iterator Entry = |
| 402 | std::upper_bound(Cache.begin(), Cache.begin()+NumSortedEntries, |
| 403 | std::make_pair(DirtyBB, MemDepResult())); |
Duncan Sands | 7050f3d | 2008-12-10 09:38:36 +0000 | [diff] [blame] | 404 | if (Entry != Cache.begin() && prior(Entry)->first == DirtyBB) |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 405 | --Entry; |
| 406 | |
| 407 | MemDepResult *ExistingResult = 0; |
| 408 | if (Entry != Cache.begin()+NumSortedEntries && |
| 409 | Entry->first == DirtyBB) { |
| 410 | // If we already have an entry, and if it isn't already dirty, the block |
| 411 | // is done. |
| 412 | if (!Entry->second.isDirty()) |
| 413 | continue; |
| 414 | |
| 415 | // Otherwise, remember this slot so we can update the value. |
| 416 | ExistingResult = &Entry->second; |
| 417 | } |
| 418 | |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 419 | // If the dirty entry has a pointer, start scanning from it so we don't have |
| 420 | // to rescan the entire block. |
| 421 | BasicBlock::iterator ScanPos = DirtyBB->end(); |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 422 | if (ExistingResult) { |
| 423 | if (Instruction *Inst = ExistingResult->getInst()) { |
| 424 | ScanPos = Inst; |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 425 | // We're removing QueryInst's use of Inst. |
Chris Lattner | 1559b36 | 2008-12-09 19:38:05 +0000 | [diff] [blame] | 426 | RemoveFromReverseMap(ReverseNonLocalDeps, Inst, |
| 427 | QueryCS.getInstruction()); |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 428 | } |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 429 | } |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 430 | |
Chris Lattner | 73ec3cd | 2008-11-30 01:26:32 +0000 | [diff] [blame] | 431 | // Find out if this block has a local dependency for QueryInst. |
Chris Lattner | d8dd934 | 2008-12-07 01:21:14 +0000 | [diff] [blame] | 432 | MemDepResult Dep; |
Chris Lattner | e79be94 | 2008-12-07 01:50:16 +0000 | [diff] [blame] | 433 | |
Chris Lattner | 1559b36 | 2008-12-09 19:38:05 +0000 | [diff] [blame] | 434 | if (ScanPos != DirtyBB->begin()) { |
Chris Lattner | 20d6f09 | 2008-12-09 21:19:42 +0000 | [diff] [blame] | 435 | Dep = getCallSiteDependencyFrom(QueryCS, isReadonlyCall,ScanPos, DirtyBB); |
Chris Lattner | 1559b36 | 2008-12-09 19:38:05 +0000 | [diff] [blame] | 436 | } else if (DirtyBB != &DirtyBB->getParent()->getEntryBlock()) { |
| 437 | // No dependence found. If this is the entry block of the function, it is |
| 438 | // a clobber, otherwise it is non-local. |
| 439 | Dep = MemDepResult::getNonLocal(); |
Chris Lattner | e79be94 | 2008-12-07 01:50:16 +0000 | [diff] [blame] | 440 | } else { |
Chris Lattner | 1559b36 | 2008-12-09 19:38:05 +0000 | [diff] [blame] | 441 | Dep = MemDepResult::getClobber(ScanPos); |
Chris Lattner | e79be94 | 2008-12-07 01:50:16 +0000 | [diff] [blame] | 442 | } |
| 443 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 444 | // If we had a dirty entry for the block, update it. Otherwise, just add |
| 445 | // a new entry. |
| 446 | if (ExistingResult) |
| 447 | *ExistingResult = Dep; |
| 448 | else |
| 449 | Cache.push_back(std::make_pair(DirtyBB, Dep)); |
| 450 | |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 451 | // If the block has a dependency (i.e. it isn't completely transparent to |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 452 | // the value), remember the association! |
| 453 | if (!Dep.isNonLocal()) { |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 454 | // Keep the ReverseNonLocalDeps map up to date so we can efficiently |
| 455 | // update this when we remove instructions. |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 456 | if (Instruction *Inst = Dep.getInst()) |
Chris Lattner | 1559b36 | 2008-12-09 19:38:05 +0000 | [diff] [blame] | 457 | ReverseNonLocalDeps[Inst].insert(QueryCS.getInstruction()); |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 458 | } else { |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 459 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 460 | // If the block *is* completely transparent to the load, we need to check |
| 461 | // the predecessors of this block. Add them to our worklist. |
Chris Lattner | 511b36c | 2008-12-09 06:44:17 +0000 | [diff] [blame] | 462 | for (BasicBlock **PI = PredCache->GetPreds(DirtyBB); *PI; ++PI) |
| 463 | DirtyBlocks.push_back(*PI); |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 464 | } |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 465 | } |
| 466 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 467 | return Cache; |
Chris Lattner | 37d041c | 2008-11-30 01:18:27 +0000 | [diff] [blame] | 468 | } |
| 469 | |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 470 | /// getNonLocalPointerDependency - Perform a full dependency query for an |
| 471 | /// access to the specified (non-volatile) memory location, returning the |
| 472 | /// set of instructions that either define or clobber the value. |
| 473 | /// |
| 474 | /// This method assumes the pointer has a "NonLocal" dependency within its |
| 475 | /// own block. |
| 476 | /// |
| 477 | void MemoryDependenceAnalysis:: |
| 478 | getNonLocalPointerDependency(Value *Pointer, bool isLoad, BasicBlock *FromBB, |
| 479 | SmallVectorImpl<NonLocalDepEntry> &Result) { |
Chris Lattner | 3f7eb5b | 2008-12-07 18:45:15 +0000 | [diff] [blame] | 480 | assert(isa<PointerType>(Pointer->getType()) && |
| 481 | "Can't get pointer deps of a non-pointer!"); |
Chris Lattner | 9a193fd | 2008-12-07 02:56:57 +0000 | [diff] [blame] | 482 | Result.clear(); |
| 483 | |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 484 | // We know that the pointer value is live into FromBB find the def/clobbers |
| 485 | // from presecessors. |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 486 | const Type *EltTy = cast<PointerType>(Pointer->getType())->getElementType(); |
| 487 | uint64_t PointeeSize = TD->getTypeStoreSize(EltTy); |
| 488 | |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 489 | // This is the set of blocks we've inspected, and the pointer we consider in |
| 490 | // each block. Because of critical edges, we currently bail out if querying |
| 491 | // a block with multiple different pointers. This can happen during PHI |
| 492 | // translation. |
| 493 | DenseMap<BasicBlock*, Value*> Visited; |
| 494 | if (!getNonLocalPointerDepFromBB(Pointer, PointeeSize, isLoad, FromBB, |
| 495 | Result, Visited, true)) |
| 496 | return; |
| 497 | Result.push_back(std::make_pair(FromBB, |
| 498 | MemDepResult::getClobber(FromBB->begin()))); |
Chris Lattner | 9a193fd | 2008-12-07 02:56:57 +0000 | [diff] [blame] | 499 | } |
| 500 | |
Chris Lattner | 9863c3f | 2008-12-09 07:47:11 +0000 | [diff] [blame] | 501 | /// GetNonLocalInfoForBlock - Compute the memdep value for BB with |
| 502 | /// Pointer/PointeeSize using either cached information in Cache or by doing a |
| 503 | /// lookup (which may use dirty cache info if available). If we do a lookup, |
| 504 | /// add the result to the cache. |
| 505 | MemDepResult MemoryDependenceAnalysis:: |
| 506 | GetNonLocalInfoForBlock(Value *Pointer, uint64_t PointeeSize, |
| 507 | bool isLoad, BasicBlock *BB, |
| 508 | NonLocalDepInfo *Cache, unsigned NumSortedEntries) { |
| 509 | |
| 510 | // Do a binary search to see if we already have an entry for this block in |
| 511 | // the cache set. If so, find it. |
| 512 | NonLocalDepInfo::iterator Entry = |
| 513 | std::upper_bound(Cache->begin(), Cache->begin()+NumSortedEntries, |
| 514 | std::make_pair(BB, MemDepResult())); |
Duncan Sands | 7050f3d | 2008-12-10 09:38:36 +0000 | [diff] [blame] | 515 | if (Entry != Cache->begin() && prior(Entry)->first == BB) |
Chris Lattner | 9863c3f | 2008-12-09 07:47:11 +0000 | [diff] [blame] | 516 | --Entry; |
| 517 | |
| 518 | MemDepResult *ExistingResult = 0; |
| 519 | if (Entry != Cache->begin()+NumSortedEntries && Entry->first == BB) |
| 520 | ExistingResult = &Entry->second; |
| 521 | |
| 522 | // If we have a cached entry, and it is non-dirty, use it as the value for |
| 523 | // this dependency. |
| 524 | if (ExistingResult && !ExistingResult->isDirty()) { |
| 525 | ++NumCacheNonLocalPtr; |
| 526 | return *ExistingResult; |
| 527 | } |
| 528 | |
| 529 | // Otherwise, we have to scan for the value. If we have a dirty cache |
| 530 | // entry, start scanning from its position, otherwise we scan from the end |
| 531 | // of the block. |
| 532 | BasicBlock::iterator ScanPos = BB->end(); |
| 533 | if (ExistingResult && ExistingResult->getInst()) { |
| 534 | assert(ExistingResult->getInst()->getParent() == BB && |
| 535 | "Instruction invalidated?"); |
| 536 | ++NumCacheDirtyNonLocalPtr; |
| 537 | ScanPos = ExistingResult->getInst(); |
| 538 | |
| 539 | // Eliminating the dirty entry from 'Cache', so update the reverse info. |
| 540 | ValueIsLoadPair CacheKey(Pointer, isLoad); |
| 541 | RemoveFromReverseMap(ReverseNonLocalPtrDeps, ScanPos, |
| 542 | CacheKey.getOpaqueValue()); |
| 543 | } else { |
| 544 | ++NumUncacheNonLocalPtr; |
| 545 | } |
| 546 | |
| 547 | // Scan the block for the dependency. |
| 548 | MemDepResult Dep = getPointerDependencyFrom(Pointer, PointeeSize, isLoad, |
| 549 | ScanPos, BB); |
| 550 | |
| 551 | // If we had a dirty entry for the block, update it. Otherwise, just add |
| 552 | // a new entry. |
| 553 | if (ExistingResult) |
| 554 | *ExistingResult = Dep; |
| 555 | else |
| 556 | Cache->push_back(std::make_pair(BB, Dep)); |
| 557 | |
| 558 | // If the block has a dependency (i.e. it isn't completely transparent to |
| 559 | // the value), remember the reverse association because we just added it |
| 560 | // to Cache! |
| 561 | if (Dep.isNonLocal()) |
| 562 | return Dep; |
| 563 | |
| 564 | // Keep the ReverseNonLocalPtrDeps map up to date so we can efficiently |
| 565 | // update MemDep when we remove instructions. |
| 566 | Instruction *Inst = Dep.getInst(); |
| 567 | assert(Inst && "Didn't depend on anything?"); |
| 568 | ValueIsLoadPair CacheKey(Pointer, isLoad); |
| 569 | ReverseNonLocalPtrDeps[Inst].insert(CacheKey.getOpaqueValue()); |
| 570 | return Dep; |
| 571 | } |
| 572 | |
| 573 | |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 574 | /// getNonLocalPointerDepFromBB - Perform a dependency query based on |
| 575 | /// pointer/pointeesize starting at the end of StartBB. Add any clobber/def |
| 576 | /// results to the results vector and keep track of which blocks are visited in |
| 577 | /// 'Visited'. |
| 578 | /// |
| 579 | /// This has special behavior for the first block queries (when SkipFirstBlock |
| 580 | /// is true). In this special case, it ignores the contents of the specified |
| 581 | /// block and starts returning dependence info for its predecessors. |
| 582 | /// |
| 583 | /// This function returns false on success, or true to indicate that it could |
| 584 | /// not compute dependence information for some reason. This should be treated |
| 585 | /// as a clobber dependence on the first instruction in the predecessor block. |
| 586 | bool MemoryDependenceAnalysis:: |
Chris Lattner | 9863c3f | 2008-12-09 07:47:11 +0000 | [diff] [blame] | 587 | getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize, |
| 588 | bool isLoad, BasicBlock *StartBB, |
| 589 | SmallVectorImpl<NonLocalDepEntry> &Result, |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 590 | DenseMap<BasicBlock*, Value*> &Visited, |
| 591 | bool SkipFirstBlock) { |
| 592 | |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 593 | // Look up the cached info for Pointer. |
| 594 | ValueIsLoadPair CacheKey(Pointer, isLoad); |
Chris Lattner | 11dcd8d | 2008-12-08 07:31:50 +0000 | [diff] [blame] | 595 | |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 596 | std::pair<BBSkipFirstBlockPair, NonLocalDepInfo> *CacheInfo = |
| 597 | &NonLocalPointerDeps[CacheKey]; |
| 598 | NonLocalDepInfo *Cache = &CacheInfo->second; |
Chris Lattner | 11dcd8d | 2008-12-08 07:31:50 +0000 | [diff] [blame] | 599 | |
| 600 | // If we have valid cached information for exactly the block we are |
| 601 | // investigating, just return it with no recomputation. |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 602 | if (CacheInfo->first == BBSkipFirstBlockPair(StartBB, SkipFirstBlock)) { |
Chris Lattner | 11dcd8d | 2008-12-08 07:31:50 +0000 | [diff] [blame] | 603 | for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end(); |
| 604 | I != E; ++I) |
| 605 | if (!I->second.isNonLocal()) |
| 606 | Result.push_back(*I); |
| 607 | ++NumCacheCompleteNonLocalPtr; |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 608 | return false; |
Chris Lattner | 11dcd8d | 2008-12-08 07:31:50 +0000 | [diff] [blame] | 609 | } |
| 610 | |
| 611 | // Otherwise, either this is a new block, a block with an invalid cache |
| 612 | // pointer or one that we're about to invalidate by putting more info into it |
| 613 | // than its valid cache info. If empty, the result will be valid cache info, |
| 614 | // otherwise it isn't. |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 615 | if (Cache->empty()) |
| 616 | CacheInfo->first = BBSkipFirstBlockPair(StartBB, SkipFirstBlock); |
| 617 | else |
| 618 | CacheInfo->first = BBSkipFirstBlockPair(); |
Chris Lattner | 11dcd8d | 2008-12-08 07:31:50 +0000 | [diff] [blame] | 619 | |
| 620 | SmallVector<BasicBlock*, 32> Worklist; |
| 621 | Worklist.push_back(StartBB); |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 622 | |
| 623 | // Keep track of the entries that we know are sorted. Previously cached |
| 624 | // entries will all be sorted. The entries we add we only sort on demand (we |
| 625 | // don't insert every element into its sorted position). We know that we |
| 626 | // won't get any reuse from currently inserted values, because we don't |
| 627 | // revisit blocks after we insert info for them. |
| 628 | unsigned NumSortedEntries = Cache->size(); |
| 629 | |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 630 | while (!Worklist.empty()) { |
Chris Lattner | 9a193fd | 2008-12-07 02:56:57 +0000 | [diff] [blame] | 631 | BasicBlock *BB = Worklist.pop_back_val(); |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 632 | |
Chris Lattner | 6563371 | 2008-12-09 07:52:59 +0000 | [diff] [blame] | 633 | // Skip the first block if we have it. |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 634 | if (!SkipFirstBlock) { |
Chris Lattner | 6563371 | 2008-12-09 07:52:59 +0000 | [diff] [blame] | 635 | // Analyze the dependency of *Pointer in FromBB. See if we already have |
| 636 | // been here. |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 637 | assert(Visited.count(BB) && "Should check 'visited' before adding to WL"); |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 638 | |
Chris Lattner | 6563371 | 2008-12-09 07:52:59 +0000 | [diff] [blame] | 639 | // Get the dependency info for Pointer in BB. If we have cached |
| 640 | // information, we will use it, otherwise we compute it. |
| 641 | MemDepResult Dep = GetNonLocalInfoForBlock(Pointer, PointeeSize, isLoad, |
| 642 | BB, Cache, NumSortedEntries); |
| 643 | |
| 644 | // If we got a Def or Clobber, add this to the list of results. |
| 645 | if (!Dep.isNonLocal()) { |
| 646 | Result.push_back(NonLocalDepEntry(BB, Dep)); |
| 647 | continue; |
| 648 | } |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 649 | } |
| 650 | |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 651 | // If 'Pointer' is an instruction defined in this block, then we need to do |
| 652 | // phi translation to change it into a value live in the predecessor block. |
| 653 | // If phi translation fails, then we can't continue dependence analysis. |
| 654 | Instruction *PtrInst = dyn_cast<Instruction>(Pointer); |
| 655 | bool NeedsPHITranslation = PtrInst && PtrInst->getParent() == BB; |
| 656 | |
| 657 | // If no PHI translation is needed, just add all the predecessors of this |
| 658 | // block to scan them as well. |
| 659 | if (!NeedsPHITranslation) { |
| 660 | SkipFirstBlock = false; |
| 661 | for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) { |
| 662 | // Verify that we haven't looked at this block yet. |
| 663 | std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool> |
| 664 | InsertRes = Visited.insert(std::make_pair(*PI, Pointer)); |
| 665 | if (InsertRes.second) { |
| 666 | // First time we've looked at *PI. |
| 667 | Worklist.push_back(*PI); |
| 668 | continue; |
| 669 | } |
| 670 | |
| 671 | // If we have seen this block before, but it was with a different |
| 672 | // pointer then we have a phi translation failure and we have to treat |
| 673 | // this as a clobber. |
| 674 | if (InsertRes.first->second != Pointer) |
| 675 | goto PredTranslationFailure; |
| 676 | } |
| 677 | continue; |
| 678 | } |
| 679 | |
| 680 | // If we do need to do phi translation, then there are a bunch of different |
| 681 | // cases, because we have to find a Value* live in the predecessor block. We |
| 682 | // know that PtrInst is defined in this block at least. |
| 683 | |
| 684 | // If this is directly a PHI node, just use the incoming values for each |
| 685 | // pred as the phi translated version. |
| 686 | if (PHINode *PtrPHI = dyn_cast<PHINode>(PtrInst)) { |
| 687 | for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI){ |
| 688 | BasicBlock *Pred = *PI; |
| 689 | Value *PredPtr = PtrPHI->getIncomingValueForBlock(Pred); |
| 690 | |
| 691 | // Check to see if we have already visited this pred block with another |
| 692 | // pointer. If so, we can't do this lookup. This failure can occur |
| 693 | // with PHI translation when a critical edge exists and the PHI node in |
| 694 | // the successor translates to a pointer value different than the |
| 695 | // pointer the block was first analyzed with. |
| 696 | std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool> |
| 697 | InsertRes = Visited.insert(std::make_pair(Pred, PredPtr)); |
| 698 | |
| 699 | if (!InsertRes.second) { |
| 700 | // If the predecessor was visited with PredPtr, then we already did |
| 701 | // the analysis and can ignore it. |
| 702 | if (InsertRes.first->second == PredPtr) |
| 703 | continue; |
| 704 | |
| 705 | // Otherwise, the block was previously analyzed with a different |
| 706 | // pointer. We can't represent the result of this case, so we just |
| 707 | // treat this as a phi translation failure. |
| 708 | goto PredTranslationFailure; |
| 709 | } |
| 710 | |
| 711 | // If we have a problem phi translating, fall through to the code below |
| 712 | // to handle the failure condition. |
| 713 | if (getNonLocalPointerDepFromBB(PredPtr, PointeeSize, isLoad, Pred, |
| 714 | Result, Visited)) |
| 715 | goto PredTranslationFailure; |
| 716 | } |
| 717 | |
| 718 | // Refresh the CacheInfo/Cache pointer so that it isn't invalidated. |
| 719 | CacheInfo = &NonLocalPointerDeps[CacheKey]; |
| 720 | Cache = &CacheInfo->second; |
| 721 | |
| 722 | // Since we did phi translation, the "Cache" set won't contain all of the |
| 723 | // results for the query. This is ok (we can still use it to accelerate |
| 724 | // specific block queries) but we can't do the fastpath "return all |
| 725 | // results from the set" Clear out the indicator for this. |
| 726 | CacheInfo->first = BBSkipFirstBlockPair(); |
| 727 | SkipFirstBlock = false; |
| 728 | continue; |
| 729 | } |
| 730 | |
| 731 | // TODO: BITCAST, GEP. |
| 732 | |
| 733 | // cerr << "MEMDEP: Could not PHI translate: " << *Pointer; |
| 734 | // if (isa<BitCastInst>(PtrInst) || isa<GetElementPtrInst>(PtrInst)) |
| 735 | // cerr << "OP:\t\t\t\t" << *PtrInst->getOperand(0); |
| 736 | PredTranslationFailure: |
| 737 | |
| 738 | // Refresh the CacheInfo/Cache pointer so that it isn't invalidated. |
| 739 | CacheInfo = &NonLocalPointerDeps[CacheKey]; |
| 740 | Cache = &CacheInfo->second; |
| 741 | |
| 742 | // Since we did phi translation, the "Cache" set won't contain all of the |
| 743 | // results for the query. This is ok (we can still use it to accelerate |
| 744 | // specific block queries) but we can't do the fastpath "return all |
| 745 | // results from the set" Clear out the indicator for this. |
| 746 | CacheInfo->first = BBSkipFirstBlockPair(); |
| 747 | |
| 748 | // If *nothing* works, mark the pointer as being clobbered by the first |
| 749 | // instruction in this block. |
| 750 | // |
| 751 | // If this is the magic first block, return this as a clobber of the whole |
| 752 | // incoming value. Since we can't phi translate to one of the predecessors, |
| 753 | // we have to bail out. |
| 754 | if (SkipFirstBlock) |
| 755 | return true; |
| 756 | |
| 757 | for (NonLocalDepInfo::reverse_iterator I = Cache->rbegin(); ; ++I) { |
| 758 | assert(I != Cache->rend() && "Didn't find current block??"); |
| 759 | if (I->first != BB) |
| 760 | continue; |
| 761 | |
| 762 | assert(I->second.isNonLocal() && |
| 763 | "Should only be here with transparent block"); |
| 764 | I->second = MemDepResult::getClobber(BB->begin()); |
| 765 | ReverseNonLocalPtrDeps[BB->begin()].insert(CacheKey.getOpaqueValue()); |
| 766 | Result.push_back(*I); |
| 767 | break; |
Chris Lattner | 9a193fd | 2008-12-07 02:56:57 +0000 | [diff] [blame] | 768 | } |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 769 | } |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 770 | |
Chris Lattner | 9863c3f | 2008-12-09 07:47:11 +0000 | [diff] [blame] | 771 | // Okay, we're done now. If we added new values to the cache, re-sort it. |
Chris Lattner | ba4dacc | 2008-12-09 07:05:45 +0000 | [diff] [blame] | 772 | switch (Cache->size()-NumSortedEntries) { |
| 773 | case 0: |
Chris Lattner | 1aeadac | 2008-12-09 06:58:04 +0000 | [diff] [blame] | 774 | // done, no new entries. |
Chris Lattner | ba4dacc | 2008-12-09 07:05:45 +0000 | [diff] [blame] | 775 | break; |
| 776 | case 2: { |
| 777 | // Two new entries, insert the last one into place. |
| 778 | NonLocalDepEntry Val = Cache->back(); |
| 779 | Cache->pop_back(); |
| 780 | NonLocalDepInfo::iterator Entry = |
| 781 | std::upper_bound(Cache->begin(), Cache->end()-1, Val); |
| 782 | Cache->insert(Entry, Val); |
| 783 | // FALL THROUGH. |
| 784 | } |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 785 | case 1: |
Chris Lattner | 1aeadac | 2008-12-09 06:58:04 +0000 | [diff] [blame] | 786 | // One new entry, Just insert the new value at the appropriate position. |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 787 | if (Cache->size() != 1) { |
| 788 | NonLocalDepEntry Val = Cache->back(); |
| 789 | Cache->pop_back(); |
| 790 | NonLocalDepInfo::iterator Entry = |
| 791 | std::upper_bound(Cache->begin(), Cache->end(), Val); |
| 792 | Cache->insert(Entry, Val); |
| 793 | } |
Chris Lattner | ba4dacc | 2008-12-09 07:05:45 +0000 | [diff] [blame] | 794 | break; |
Chris Lattner | ba4dacc | 2008-12-09 07:05:45 +0000 | [diff] [blame] | 795 | default: |
Chris Lattner | 1aeadac | 2008-12-09 06:58:04 +0000 | [diff] [blame] | 796 | // Added many values, do a full scale sort. |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 797 | std::sort(Cache->begin(), Cache->end()); |
Chris Lattner | 1aeadac | 2008-12-09 06:58:04 +0000 | [diff] [blame] | 798 | } |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 799 | |
| 800 | return false; |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 801 | } |
| 802 | |
| 803 | /// RemoveCachedNonLocalPointerDependencies - If P exists in |
| 804 | /// CachedNonLocalPointerInfo, remove it. |
| 805 | void MemoryDependenceAnalysis:: |
| 806 | RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair P) { |
| 807 | CachedNonLocalPointerInfo::iterator It = |
| 808 | NonLocalPointerDeps.find(P); |
| 809 | if (It == NonLocalPointerDeps.end()) return; |
| 810 | |
| 811 | // Remove all of the entries in the BB->val map. This involves removing |
| 812 | // instructions from the reverse map. |
Chris Lattner | 11dcd8d | 2008-12-08 07:31:50 +0000 | [diff] [blame] | 813 | NonLocalDepInfo &PInfo = It->second.second; |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 814 | |
| 815 | for (unsigned i = 0, e = PInfo.size(); i != e; ++i) { |
| 816 | Instruction *Target = PInfo[i].second.getInst(); |
| 817 | if (Target == 0) continue; // Ignore non-local dep results. |
Chris Lattner | 5a45bf1 | 2008-12-09 22:45:32 +0000 | [diff] [blame] | 818 | assert(Target->getParent() == PInfo[i].first); |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 819 | |
| 820 | // Eliminating the dirty entry from 'Cache', so update the reverse info. |
Chris Lattner | d44745d | 2008-12-07 18:39:13 +0000 | [diff] [blame] | 821 | RemoveFromReverseMap(ReverseNonLocalPtrDeps, Target, P.getOpaqueValue()); |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 822 | } |
| 823 | |
| 824 | // Remove P from NonLocalPointerDeps (which deletes NonLocalDepInfo). |
| 825 | NonLocalPointerDeps.erase(It); |
Chris Lattner | 7ebcf03 | 2008-12-07 02:15:47 +0000 | [diff] [blame] | 826 | } |
| 827 | |
| 828 | |
Chris Lattner | bc99be1 | 2008-12-09 22:06:23 +0000 | [diff] [blame] | 829 | /// invalidateCachedPointerInfo - This method is used to invalidate cached |
| 830 | /// information about the specified pointer, because it may be too |
| 831 | /// conservative in memdep. This is an optional call that can be used when |
| 832 | /// the client detects an equivalence between the pointer and some other |
| 833 | /// value and replaces the other value with ptr. This can make Ptr available |
| 834 | /// in more places that cached info does not necessarily keep. |
| 835 | void MemoryDependenceAnalysis::invalidateCachedPointerInfo(Value *Ptr) { |
| 836 | // If Ptr isn't really a pointer, just ignore it. |
| 837 | if (!isa<PointerType>(Ptr->getType())) return; |
| 838 | // Flush store info for the pointer. |
| 839 | RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, false)); |
| 840 | // Flush load info for the pointer. |
| 841 | RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, true)); |
| 842 | } |
| 843 | |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 844 | /// removeInstruction - Remove an instruction from the dependence analysis, |
| 845 | /// updating the dependence of instructions that previously depended on it. |
Owen Anderson | 642a9e3 | 2007-08-08 22:26:03 +0000 | [diff] [blame] | 846 | /// This method attempts to keep the cache coherent using the reverse map. |
Chris Lattner | 5f589dc | 2008-11-28 22:04:47 +0000 | [diff] [blame] | 847 | void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) { |
Chris Lattner | 5f589dc | 2008-11-28 22:04:47 +0000 | [diff] [blame] | 848 | // Walk through the Non-local dependencies, removing this one as the value |
| 849 | // for any cached queries. |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 850 | NonLocalDepMapType::iterator NLDI = NonLocalDeps.find(RemInst); |
| 851 | if (NLDI != NonLocalDeps.end()) { |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 852 | NonLocalDepInfo &BlockMap = NLDI->second.first; |
Chris Lattner | 25f4b2b | 2008-11-30 02:30:50 +0000 | [diff] [blame] | 853 | for (NonLocalDepInfo::iterator DI = BlockMap.begin(), DE = BlockMap.end(); |
| 854 | DI != DE; ++DI) |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 855 | if (Instruction *Inst = DI->second.getInst()) |
Chris Lattner | d44745d | 2008-12-07 18:39:13 +0000 | [diff] [blame] | 856 | RemoveFromReverseMap(ReverseNonLocalDeps, Inst, RemInst); |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 857 | NonLocalDeps.erase(NLDI); |
| 858 | } |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 859 | |
Chris Lattner | 5f589dc | 2008-11-28 22:04:47 +0000 | [diff] [blame] | 860 | // If we have a cached local dependence query for this instruction, remove it. |
Chris Lattner | baad888 | 2008-11-28 22:28:27 +0000 | [diff] [blame] | 861 | // |
Chris Lattner | 39f372e | 2008-11-29 01:43:36 +0000 | [diff] [blame] | 862 | LocalDepMapType::iterator LocalDepEntry = LocalDeps.find(RemInst); |
| 863 | if (LocalDepEntry != LocalDeps.end()) { |
Chris Lattner | 125ce36 | 2008-11-30 01:09:30 +0000 | [diff] [blame] | 864 | // Remove us from DepInst's reverse set now that the local dep info is gone. |
Chris Lattner | d44745d | 2008-12-07 18:39:13 +0000 | [diff] [blame] | 865 | if (Instruction *Inst = LocalDepEntry->second.getInst()) |
| 866 | RemoveFromReverseMap(ReverseLocalDeps, Inst, RemInst); |
Chris Lattner | 125ce36 | 2008-11-30 01:09:30 +0000 | [diff] [blame] | 867 | |
Chris Lattner | baad888 | 2008-11-28 22:28:27 +0000 | [diff] [blame] | 868 | // Remove this local dependency info. |
Chris Lattner | 39f372e | 2008-11-29 01:43:36 +0000 | [diff] [blame] | 869 | LocalDeps.erase(LocalDepEntry); |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 870 | } |
| 871 | |
| 872 | // If we have any cached pointer dependencies on this instruction, remove |
| 873 | // them. If the instruction has non-pointer type, then it can't be a pointer |
| 874 | // base. |
| 875 | |
| 876 | // Remove it from both the load info and the store info. The instruction |
| 877 | // can't be in either of these maps if it is non-pointer. |
| 878 | if (isa<PointerType>(RemInst->getType())) { |
| 879 | RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, false)); |
| 880 | RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, true)); |
| 881 | } |
Chris Lattner | baad888 | 2008-11-28 22:28:27 +0000 | [diff] [blame] | 882 | |
Chris Lattner | d3d12ec | 2008-11-28 22:51:08 +0000 | [diff] [blame] | 883 | // Loop over all of the things that depend on the instruction we're removing. |
| 884 | // |
Chris Lattner | 4f8c18c | 2008-11-29 23:30:39 +0000 | [diff] [blame] | 885 | SmallVector<std::pair<Instruction*, Instruction*>, 8> ReverseDepsToAdd; |
Chris Lattner | 0655f73 | 2008-12-07 18:42:51 +0000 | [diff] [blame] | 886 | |
| 887 | // If we find RemInst as a clobber or Def in any of the maps for other values, |
| 888 | // we need to replace its entry with a dirty version of the instruction after |
| 889 | // it. If RemInst is a terminator, we use a null dirty value. |
| 890 | // |
| 891 | // Using a dirty version of the instruction after RemInst saves having to scan |
| 892 | // the entire block to get to this point. |
| 893 | MemDepResult NewDirtyVal; |
| 894 | if (!RemInst->isTerminator()) |
| 895 | NewDirtyVal = MemDepResult::getDirty(++BasicBlock::iterator(RemInst)); |
Chris Lattner | 4f8c18c | 2008-11-29 23:30:39 +0000 | [diff] [blame] | 896 | |
Chris Lattner | 8c46527 | 2008-11-29 09:20:15 +0000 | [diff] [blame] | 897 | ReverseDepMapType::iterator ReverseDepIt = ReverseLocalDeps.find(RemInst); |
| 898 | if (ReverseDepIt != ReverseLocalDeps.end()) { |
Chris Lattner | d3d12ec | 2008-11-28 22:51:08 +0000 | [diff] [blame] | 899 | SmallPtrSet<Instruction*, 4> &ReverseDeps = ReverseDepIt->second; |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 900 | // RemInst can't be the terminator if it has local stuff depending on it. |
Chris Lattner | 125ce36 | 2008-11-30 01:09:30 +0000 | [diff] [blame] | 901 | assert(!ReverseDeps.empty() && !isa<TerminatorInst>(RemInst) && |
| 902 | "Nothing can locally depend on a terminator"); |
| 903 | |
Chris Lattner | d3d12ec | 2008-11-28 22:51:08 +0000 | [diff] [blame] | 904 | for (SmallPtrSet<Instruction*, 4>::iterator I = ReverseDeps.begin(), |
| 905 | E = ReverseDeps.end(); I != E; ++I) { |
| 906 | Instruction *InstDependingOnRemInst = *I; |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 907 | assert(InstDependingOnRemInst != RemInst && |
| 908 | "Already removed our local dep info"); |
Chris Lattner | 125ce36 | 2008-11-30 01:09:30 +0000 | [diff] [blame] | 909 | |
Chris Lattner | 0655f73 | 2008-12-07 18:42:51 +0000 | [diff] [blame] | 910 | LocalDeps[InstDependingOnRemInst] = NewDirtyVal; |
Chris Lattner | d3d12ec | 2008-11-28 22:51:08 +0000 | [diff] [blame] | 911 | |
Chris Lattner | 125ce36 | 2008-11-30 01:09:30 +0000 | [diff] [blame] | 912 | // Make sure to remember that new things depend on NewDepInst. |
Chris Lattner | 0655f73 | 2008-12-07 18:42:51 +0000 | [diff] [blame] | 913 | assert(NewDirtyVal.getInst() && "There is no way something else can have " |
| 914 | "a local dep on this if it is a terminator!"); |
| 915 | ReverseDepsToAdd.push_back(std::make_pair(NewDirtyVal.getInst(), |
Chris Lattner | 125ce36 | 2008-11-30 01:09:30 +0000 | [diff] [blame] | 916 | InstDependingOnRemInst)); |
Chris Lattner | d3d12ec | 2008-11-28 22:51:08 +0000 | [diff] [blame] | 917 | } |
Chris Lattner | 4f8c18c | 2008-11-29 23:30:39 +0000 | [diff] [blame] | 918 | |
| 919 | ReverseLocalDeps.erase(ReverseDepIt); |
| 920 | |
| 921 | // Add new reverse deps after scanning the set, to avoid invalidating the |
| 922 | // 'ReverseDeps' reference. |
| 923 | while (!ReverseDepsToAdd.empty()) { |
| 924 | ReverseLocalDeps[ReverseDepsToAdd.back().first] |
| 925 | .insert(ReverseDepsToAdd.back().second); |
| 926 | ReverseDepsToAdd.pop_back(); |
| 927 | } |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 928 | } |
Owen Anderson | 4d13de4 | 2007-08-16 21:27:05 +0000 | [diff] [blame] | 929 | |
Chris Lattner | 8c46527 | 2008-11-29 09:20:15 +0000 | [diff] [blame] | 930 | ReverseDepIt = ReverseNonLocalDeps.find(RemInst); |
| 931 | if (ReverseDepIt != ReverseNonLocalDeps.end()) { |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 932 | SmallPtrSet<Instruction*, 4> &Set = ReverseDepIt->second; |
| 933 | for (SmallPtrSet<Instruction*, 4>::iterator I = Set.begin(), E = Set.end(); |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 934 | I != E; ++I) { |
| 935 | assert(*I != RemInst && "Already removed NonLocalDep info for RemInst"); |
| 936 | |
Chris Lattner | 4a69bad | 2008-11-30 02:52:26 +0000 | [diff] [blame] | 937 | PerInstNLInfo &INLD = NonLocalDeps[*I]; |
Chris Lattner | 4a69bad | 2008-11-30 02:52:26 +0000 | [diff] [blame] | 938 | // The information is now dirty! |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 939 | INLD.second = true; |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 940 | |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 941 | for (NonLocalDepInfo::iterator DI = INLD.first.begin(), |
| 942 | DE = INLD.first.end(); DI != DE; ++DI) { |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 943 | if (DI->second.getInst() != RemInst) continue; |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 944 | |
| 945 | // Convert to a dirty entry for the subsequent instruction. |
Chris Lattner | 0655f73 | 2008-12-07 18:42:51 +0000 | [diff] [blame] | 946 | DI->second = NewDirtyVal; |
| 947 | |
| 948 | if (Instruction *NextI = NewDirtyVal.getInst()) |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 949 | ReverseDepsToAdd.push_back(std::make_pair(NextI, *I)); |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 950 | } |
| 951 | } |
Chris Lattner | 4f8c18c | 2008-11-29 23:30:39 +0000 | [diff] [blame] | 952 | |
| 953 | ReverseNonLocalDeps.erase(ReverseDepIt); |
| 954 | |
Chris Lattner | 0ec48dd | 2008-11-29 22:02:15 +0000 | [diff] [blame] | 955 | // Add new reverse deps after scanning the set, to avoid invalidating 'Set' |
| 956 | while (!ReverseDepsToAdd.empty()) { |
| 957 | ReverseNonLocalDeps[ReverseDepsToAdd.back().first] |
| 958 | .insert(ReverseDepsToAdd.back().second); |
| 959 | ReverseDepsToAdd.pop_back(); |
| 960 | } |
Owen Anderson | 4d13de4 | 2007-08-16 21:27:05 +0000 | [diff] [blame] | 961 | } |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 962 | |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 963 | // If the instruction is in ReverseNonLocalPtrDeps then it appears as a |
| 964 | // value in the NonLocalPointerDeps info. |
| 965 | ReverseNonLocalPtrDepTy::iterator ReversePtrDepIt = |
| 966 | ReverseNonLocalPtrDeps.find(RemInst); |
| 967 | if (ReversePtrDepIt != ReverseNonLocalPtrDeps.end()) { |
| 968 | SmallPtrSet<void*, 4> &Set = ReversePtrDepIt->second; |
| 969 | SmallVector<std::pair<Instruction*, ValueIsLoadPair>,8> ReversePtrDepsToAdd; |
| 970 | |
| 971 | for (SmallPtrSet<void*, 4>::iterator I = Set.begin(), E = Set.end(); |
| 972 | I != E; ++I) { |
| 973 | ValueIsLoadPair P; |
| 974 | P.setFromOpaqueValue(*I); |
| 975 | assert(P.getPointer() != RemInst && |
| 976 | "Already removed NonLocalPointerDeps info for RemInst"); |
| 977 | |
Chris Lattner | 11dcd8d | 2008-12-08 07:31:50 +0000 | [diff] [blame] | 978 | NonLocalDepInfo &NLPDI = NonLocalPointerDeps[P].second; |
| 979 | |
| 980 | // The cache is not valid for any specific block anymore. |
Chris Lattner | 9e59c64 | 2008-12-15 03:35:32 +0000 | [diff] [blame^] | 981 | NonLocalPointerDeps[P].first = BBSkipFirstBlockPair(); |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 982 | |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 983 | // Update any entries for RemInst to use the instruction after it. |
| 984 | for (NonLocalDepInfo::iterator DI = NLPDI.begin(), DE = NLPDI.end(); |
| 985 | DI != DE; ++DI) { |
| 986 | if (DI->second.getInst() != RemInst) continue; |
| 987 | |
| 988 | // Convert to a dirty entry for the subsequent instruction. |
| 989 | DI->second = NewDirtyVal; |
| 990 | |
| 991 | if (Instruction *NewDirtyInst = NewDirtyVal.getInst()) |
| 992 | ReversePtrDepsToAdd.push_back(std::make_pair(NewDirtyInst, P)); |
| 993 | } |
| 994 | } |
| 995 | |
| 996 | ReverseNonLocalPtrDeps.erase(ReversePtrDepIt); |
| 997 | |
| 998 | while (!ReversePtrDepsToAdd.empty()) { |
| 999 | ReverseNonLocalPtrDeps[ReversePtrDepsToAdd.back().first] |
| 1000 | .insert(ReversePtrDepsToAdd.back().second.getOpaqueValue()); |
| 1001 | ReversePtrDepsToAdd.pop_back(); |
| 1002 | } |
| 1003 | } |
| 1004 | |
| 1005 | |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 1006 | assert(!NonLocalDeps.count(RemInst) && "RemInst got reinserted?"); |
Chris Lattner | d777d40 | 2008-11-30 19:24:31 +0000 | [diff] [blame] | 1007 | AA->deleteValue(RemInst); |
Chris Lattner | 5f589dc | 2008-11-28 22:04:47 +0000 | [diff] [blame] | 1008 | DEBUG(verifyRemoved(RemInst)); |
Owen Anderson | 78e02f7 | 2007-07-06 23:14:35 +0000 | [diff] [blame] | 1009 | } |
Chris Lattner | 729b237 | 2008-11-29 21:25:10 +0000 | [diff] [blame] | 1010 | /// verifyRemoved - Verify that the specified instruction does not occur |
| 1011 | /// in our internal data structures. |
| 1012 | void MemoryDependenceAnalysis::verifyRemoved(Instruction *D) const { |
| 1013 | for (LocalDepMapType::const_iterator I = LocalDeps.begin(), |
| 1014 | E = LocalDeps.end(); I != E; ++I) { |
| 1015 | assert(I->first != D && "Inst occurs in data structures"); |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 1016 | assert(I->second.getInst() != D && |
Chris Lattner | 729b237 | 2008-11-29 21:25:10 +0000 | [diff] [blame] | 1017 | "Inst occurs in data structures"); |
| 1018 | } |
| 1019 | |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 1020 | for (CachedNonLocalPointerInfo::const_iterator I =NonLocalPointerDeps.begin(), |
| 1021 | E = NonLocalPointerDeps.end(); I != E; ++I) { |
| 1022 | assert(I->first.getPointer() != D && "Inst occurs in NLPD map key"); |
Chris Lattner | 11dcd8d | 2008-12-08 07:31:50 +0000 | [diff] [blame] | 1023 | const NonLocalDepInfo &Val = I->second.second; |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 1024 | for (NonLocalDepInfo::const_iterator II = Val.begin(), E = Val.end(); |
| 1025 | II != E; ++II) |
| 1026 | assert(II->second.getInst() != D && "Inst occurs as NLPD value"); |
| 1027 | } |
| 1028 | |
Chris Lattner | 729b237 | 2008-11-29 21:25:10 +0000 | [diff] [blame] | 1029 | for (NonLocalDepMapType::const_iterator I = NonLocalDeps.begin(), |
| 1030 | E = NonLocalDeps.end(); I != E; ++I) { |
| 1031 | assert(I->first != D && "Inst occurs in data structures"); |
Chris Lattner | 4a69bad | 2008-11-30 02:52:26 +0000 | [diff] [blame] | 1032 | const PerInstNLInfo &INLD = I->second; |
Chris Lattner | bf145d6 | 2008-12-01 01:15:42 +0000 | [diff] [blame] | 1033 | for (NonLocalDepInfo::const_iterator II = INLD.first.begin(), |
| 1034 | EE = INLD.first.end(); II != EE; ++II) |
Chris Lattner | fd3dcbe | 2008-11-30 23:17:19 +0000 | [diff] [blame] | 1035 | assert(II->second.getInst() != D && "Inst occurs in data structures"); |
Chris Lattner | 729b237 | 2008-11-29 21:25:10 +0000 | [diff] [blame] | 1036 | } |
| 1037 | |
| 1038 | for (ReverseDepMapType::const_iterator I = ReverseLocalDeps.begin(), |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 1039 | E = ReverseLocalDeps.end(); I != E; ++I) { |
| 1040 | assert(I->first != D && "Inst occurs in data structures"); |
Chris Lattner | 729b237 | 2008-11-29 21:25:10 +0000 | [diff] [blame] | 1041 | for (SmallPtrSet<Instruction*, 4>::const_iterator II = I->second.begin(), |
| 1042 | EE = I->second.end(); II != EE; ++II) |
| 1043 | assert(*II != D && "Inst occurs in data structures"); |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 1044 | } |
Chris Lattner | 729b237 | 2008-11-29 21:25:10 +0000 | [diff] [blame] | 1045 | |
| 1046 | for (ReverseDepMapType::const_iterator I = ReverseNonLocalDeps.begin(), |
| 1047 | E = ReverseNonLocalDeps.end(); |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 1048 | I != E; ++I) { |
| 1049 | assert(I->first != D && "Inst occurs in data structures"); |
Chris Lattner | 729b237 | 2008-11-29 21:25:10 +0000 | [diff] [blame] | 1050 | for (SmallPtrSet<Instruction*, 4>::const_iterator II = I->second.begin(), |
| 1051 | EE = I->second.end(); II != EE; ++II) |
| 1052 | assert(*II != D && "Inst occurs in data structures"); |
Chris Lattner | f68f310 | 2008-11-30 02:28:25 +0000 | [diff] [blame] | 1053 | } |
Chris Lattner | 6290f5c | 2008-12-07 08:50:20 +0000 | [diff] [blame] | 1054 | |
| 1055 | for (ReverseNonLocalPtrDepTy::const_iterator |
| 1056 | I = ReverseNonLocalPtrDeps.begin(), |
| 1057 | E = ReverseNonLocalPtrDeps.end(); I != E; ++I) { |
| 1058 | assert(I->first != D && "Inst occurs in rev NLPD map"); |
| 1059 | |
| 1060 | for (SmallPtrSet<void*, 4>::const_iterator II = I->second.begin(), |
| 1061 | E = I->second.end(); II != E; ++II) |
| 1062 | assert(*II != ValueIsLoadPair(D, false).getOpaqueValue() && |
| 1063 | *II != ValueIsLoadPair(D, true).getOpaqueValue() && |
| 1064 | "Inst occurs in ReverseNonLocalPtrDeps map"); |
| 1065 | } |
| 1066 | |
Chris Lattner | 729b237 | 2008-11-29 21:25:10 +0000 | [diff] [blame] | 1067 | } |