John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 1 | //===-- DifferenceEngine.cpp - Structural function/module comparison ------===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
John McCall | 73b21b7 | 2010-07-29 18:08:23 +0000 | [diff] [blame] | 10 | // This header defines the implementation of the LLVM difference |
| 11 | // engine, which structurally compares global values within a module. |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 12 | // |
| 13 | //===----------------------------------------------------------------------===// |
| 14 | |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 15 | #include "DifferenceEngine.h" |
| 16 | |
Jay Foad | 562b84b | 2011-04-11 09:35:34 +0000 | [diff] [blame] | 17 | #include "llvm/Constants.h" |
John McCall | 73b21b7 | 2010-07-29 18:08:23 +0000 | [diff] [blame] | 18 | #include "llvm/Function.h" |
| 19 | #include "llvm/Instructions.h" |
| 20 | #include "llvm/Module.h" |
| 21 | #include "llvm/ADT/DenseMap.h" |
| 22 | #include "llvm/ADT/DenseSet.h" |
| 23 | #include "llvm/ADT/SmallVector.h" |
| 24 | #include "llvm/ADT/StringRef.h" |
| 25 | #include "llvm/ADT/StringSet.h" |
| 26 | #include "llvm/Support/CallSite.h" |
| 27 | #include "llvm/Support/CFG.h" |
| 28 | #include "llvm/Support/ErrorHandling.h" |
| 29 | #include "llvm/Support/raw_ostream.h" |
| 30 | #include "llvm/Support/type_traits.h" |
| 31 | |
| 32 | #include <utility> |
| 33 | |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 34 | using namespace llvm; |
| 35 | |
| 36 | namespace { |
| 37 | |
| 38 | /// A priority queue, implemented as a heap. |
| 39 | template <class T, class Sorter, unsigned InlineCapacity> |
| 40 | class PriorityQueue { |
| 41 | Sorter Precedes; |
| 42 | llvm::SmallVector<T, InlineCapacity> Storage; |
| 43 | |
| 44 | public: |
| 45 | PriorityQueue(const Sorter &Precedes) : Precedes(Precedes) {} |
| 46 | |
| 47 | /// Checks whether the heap is empty. |
| 48 | bool empty() const { return Storage.empty(); } |
| 49 | |
| 50 | /// Insert a new value on the heap. |
| 51 | void insert(const T &V) { |
| 52 | unsigned Index = Storage.size(); |
| 53 | Storage.push_back(V); |
| 54 | if (Index == 0) return; |
| 55 | |
| 56 | T *data = Storage.data(); |
| 57 | while (true) { |
| 58 | unsigned Target = (Index + 1) / 2 - 1; |
| 59 | if (!Precedes(data[Index], data[Target])) return; |
| 60 | std::swap(data[Index], data[Target]); |
| 61 | if (Target == 0) return; |
| 62 | Index = Target; |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | /// Remove the minimum value in the heap. Only valid on a non-empty heap. |
| 67 | T remove_min() { |
| 68 | assert(!empty()); |
| 69 | T tmp = Storage[0]; |
| 70 | |
| 71 | unsigned NewSize = Storage.size() - 1; |
| 72 | if (NewSize) { |
| 73 | // Move the slot at the end to the beginning. |
| 74 | if (isPodLike<T>::value) |
| 75 | Storage[0] = Storage[NewSize]; |
| 76 | else |
| 77 | std::swap(Storage[0], Storage[NewSize]); |
| 78 | |
| 79 | // Bubble the root up as necessary. |
| 80 | unsigned Index = 0; |
| 81 | while (true) { |
| 82 | // With a 1-based index, the children would be Index*2 and Index*2+1. |
| 83 | unsigned R = (Index + 1) * 2; |
| 84 | unsigned L = R - 1; |
| 85 | |
| 86 | // If R is out of bounds, we're done after this in any case. |
| 87 | if (R >= NewSize) { |
| 88 | // If L is also out of bounds, we're done immediately. |
| 89 | if (L >= NewSize) break; |
| 90 | |
| 91 | // Otherwise, test whether we should swap L and Index. |
| 92 | if (Precedes(Storage[L], Storage[Index])) |
| 93 | std::swap(Storage[L], Storage[Index]); |
| 94 | break; |
| 95 | } |
| 96 | |
| 97 | // Otherwise, we need to compare with the smaller of L and R. |
| 98 | // Prefer R because it's closer to the end of the array. |
| 99 | unsigned IndexToTest = (Precedes(Storage[L], Storage[R]) ? L : R); |
| 100 | |
| 101 | // If Index is >= the min of L and R, then heap ordering is restored. |
| 102 | if (!Precedes(Storage[IndexToTest], Storage[Index])) |
| 103 | break; |
| 104 | |
| 105 | // Otherwise, keep bubbling up. |
| 106 | std::swap(Storage[IndexToTest], Storage[Index]); |
| 107 | Index = IndexToTest; |
| 108 | } |
| 109 | } |
| 110 | Storage.pop_back(); |
| 111 | |
| 112 | return tmp; |
| 113 | } |
| 114 | }; |
| 115 | |
| 116 | /// A function-scope difference engine. |
| 117 | class FunctionDifferenceEngine { |
| 118 | DifferenceEngine &Engine; |
| 119 | |
| 120 | /// The current mapping from old local values to new local values. |
| 121 | DenseMap<Value*, Value*> Values; |
| 122 | |
| 123 | /// The current mapping from old blocks to new blocks. |
| 124 | DenseMap<BasicBlock*, BasicBlock*> Blocks; |
| 125 | |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 126 | DenseSet<std::pair<Value*, Value*> > TentativeValues; |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 127 | |
| 128 | unsigned getUnprocPredCount(BasicBlock *Block) const { |
| 129 | unsigned Count = 0; |
| 130 | for (pred_iterator I = pred_begin(Block), E = pred_end(Block); I != E; ++I) |
| 131 | if (!Blocks.count(*I)) Count++; |
| 132 | return Count; |
| 133 | } |
| 134 | |
| 135 | typedef std::pair<BasicBlock*, BasicBlock*> BlockPair; |
| 136 | |
| 137 | /// A type which sorts a priority queue by the number of unprocessed |
| 138 | /// predecessor blocks it has remaining. |
| 139 | /// |
| 140 | /// This is actually really expensive to calculate. |
| 141 | struct QueueSorter { |
| 142 | const FunctionDifferenceEngine &fde; |
| 143 | explicit QueueSorter(const FunctionDifferenceEngine &fde) : fde(fde) {} |
| 144 | |
| 145 | bool operator()(const BlockPair &Old, const BlockPair &New) { |
| 146 | return fde.getUnprocPredCount(Old.first) |
| 147 | < fde.getUnprocPredCount(New.first); |
| 148 | } |
| 149 | }; |
| 150 | |
| 151 | /// A queue of unified blocks to process. |
| 152 | PriorityQueue<BlockPair, QueueSorter, 20> Queue; |
| 153 | |
| 154 | /// Try to unify the given two blocks. Enqueues them for processing |
| 155 | /// if they haven't already been processed. |
| 156 | /// |
| 157 | /// Returns true if there was a problem unifying them. |
| 158 | bool tryUnify(BasicBlock *L, BasicBlock *R) { |
| 159 | BasicBlock *&Ref = Blocks[L]; |
| 160 | |
| 161 | if (Ref) { |
| 162 | if (Ref == R) return false; |
| 163 | |
John McCall | 62dc1f3 | 2010-07-29 08:14:41 +0000 | [diff] [blame] | 164 | Engine.logf("successor %l cannot be equivalent to %r; " |
| 165 | "it's already equivalent to %r") |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 166 | << L << R << Ref; |
| 167 | return true; |
| 168 | } |
| 169 | |
| 170 | Ref = R; |
| 171 | Queue.insert(BlockPair(L, R)); |
| 172 | return false; |
| 173 | } |
John McCall | 82bd5ea | 2010-07-29 09:20:34 +0000 | [diff] [blame] | 174 | |
| 175 | /// Unifies two instructions, given that they're known not to have |
| 176 | /// structural differences. |
| 177 | void unify(Instruction *L, Instruction *R) { |
| 178 | DifferenceEngine::Context C(Engine, L, R); |
| 179 | |
| 180 | bool Result = diff(L, R, true, true); |
| 181 | assert(!Result && "structural differences second time around?"); |
| 182 | (void) Result; |
| 183 | if (!L->use_empty()) |
| 184 | Values[L] = R; |
| 185 | } |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 186 | |
| 187 | void processQueue() { |
| 188 | while (!Queue.empty()) { |
| 189 | BlockPair Pair = Queue.remove_min(); |
| 190 | diff(Pair.first, Pair.second); |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | void diff(BasicBlock *L, BasicBlock *R) { |
| 195 | DifferenceEngine::Context C(Engine, L, R); |
| 196 | |
| 197 | BasicBlock::iterator LI = L->begin(), LE = L->end(); |
Duncan Sands | 1f6a329 | 2011-08-12 14:54:45 +0000 | [diff] [blame] | 198 | BasicBlock::iterator RI = R->begin(); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 199 | |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 200 | llvm::SmallVector<std::pair<Instruction*,Instruction*>, 20> TentativePairs; |
| 201 | |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 202 | do { |
Duncan Sands | 1f6a329 | 2011-08-12 14:54:45 +0000 | [diff] [blame] | 203 | assert(LI != LE && RI != R->end()); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 204 | Instruction *LeftI = &*LI, *RightI = &*RI; |
| 205 | |
| 206 | // If the instructions differ, start the more sophisticated diff |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 207 | // algorithm at the start of the block. |
John McCall | e292143 | 2010-07-29 09:04:45 +0000 | [diff] [blame] | 208 | if (diff(LeftI, RightI, false, false)) { |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 209 | TentativeValues.clear(); |
| 210 | return runBlockDiff(L->begin(), R->begin()); |
| 211 | } |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 212 | |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 213 | // Otherwise, tentatively unify them. |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 214 | if (!LeftI->use_empty()) |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 215 | TentativeValues.insert(std::make_pair(LeftI, RightI)); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 216 | |
| 217 | ++LI, ++RI; |
| 218 | } while (LI != LE); // This is sufficient: we can't get equality of |
| 219 | // terminators if there are residual instructions. |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 220 | |
John McCall | 82bd5ea | 2010-07-29 09:20:34 +0000 | [diff] [blame] | 221 | // Unify everything in the block, non-tentatively this time. |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 222 | TentativeValues.clear(); |
John McCall | 82bd5ea | 2010-07-29 09:20:34 +0000 | [diff] [blame] | 223 | for (LI = L->begin(), RI = R->begin(); LI != LE; ++LI, ++RI) |
| 224 | unify(&*LI, &*RI); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 225 | } |
| 226 | |
| 227 | bool matchForBlockDiff(Instruction *L, Instruction *R); |
| 228 | void runBlockDiff(BasicBlock::iterator LI, BasicBlock::iterator RI); |
| 229 | |
| 230 | bool diffCallSites(CallSite L, CallSite R, bool Complain) { |
| 231 | // FIXME: call attributes |
| 232 | if (!equivalentAsOperands(L.getCalledValue(), R.getCalledValue())) { |
| 233 | if (Complain) Engine.log("called functions differ"); |
| 234 | return true; |
| 235 | } |
| 236 | if (L.arg_size() != R.arg_size()) { |
| 237 | if (Complain) Engine.log("argument counts differ"); |
| 238 | return true; |
| 239 | } |
| 240 | for (unsigned I = 0, E = L.arg_size(); I != E; ++I) |
| 241 | if (!equivalentAsOperands(L.getArgument(I), R.getArgument(I))) { |
| 242 | if (Complain) |
John McCall | 62dc1f3 | 2010-07-29 08:14:41 +0000 | [diff] [blame] | 243 | Engine.logf("arguments %l and %r differ") |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 244 | << L.getArgument(I) << R.getArgument(I); |
| 245 | return true; |
| 246 | } |
| 247 | return false; |
| 248 | } |
| 249 | |
| 250 | bool diff(Instruction *L, Instruction *R, bool Complain, bool TryUnify) { |
| 251 | // FIXME: metadata (if Complain is set) |
| 252 | |
| 253 | // Different opcodes always imply different operations. |
| 254 | if (L->getOpcode() != R->getOpcode()) { |
| 255 | if (Complain) Engine.log("different instruction types"); |
| 256 | return true; |
| 257 | } |
| 258 | |
| 259 | if (isa<CmpInst>(L)) { |
| 260 | if (cast<CmpInst>(L)->getPredicate() |
| 261 | != cast<CmpInst>(R)->getPredicate()) { |
| 262 | if (Complain) Engine.log("different predicates"); |
| 263 | return true; |
| 264 | } |
| 265 | } else if (isa<CallInst>(L)) { |
| 266 | return diffCallSites(CallSite(L), CallSite(R), Complain); |
| 267 | } else if (isa<PHINode>(L)) { |
| 268 | // FIXME: implement. |
| 269 | |
Chris Lattner | 7a2bdde | 2011-04-15 05:18:47 +0000 | [diff] [blame] | 270 | // This is really weird; type uniquing is broken? |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 271 | if (L->getType() != R->getType()) { |
| 272 | if (!L->getType()->isPointerTy() || !R->getType()->isPointerTy()) { |
| 273 | if (Complain) Engine.log("different phi types"); |
| 274 | return true; |
| 275 | } |
| 276 | } |
| 277 | return false; |
| 278 | |
| 279 | // Terminators. |
| 280 | } else if (isa<InvokeInst>(L)) { |
| 281 | InvokeInst *LI = cast<InvokeInst>(L); |
| 282 | InvokeInst *RI = cast<InvokeInst>(R); |
| 283 | if (diffCallSites(CallSite(LI), CallSite(RI), Complain)) |
| 284 | return true; |
| 285 | |
| 286 | if (TryUnify) { |
| 287 | tryUnify(LI->getNormalDest(), RI->getNormalDest()); |
| 288 | tryUnify(LI->getUnwindDest(), RI->getUnwindDest()); |
| 289 | } |
| 290 | return false; |
| 291 | |
| 292 | } else if (isa<BranchInst>(L)) { |
| 293 | BranchInst *LI = cast<BranchInst>(L); |
| 294 | BranchInst *RI = cast<BranchInst>(R); |
| 295 | if (LI->isConditional() != RI->isConditional()) { |
| 296 | if (Complain) Engine.log("branch conditionality differs"); |
| 297 | return true; |
| 298 | } |
| 299 | |
| 300 | if (LI->isConditional()) { |
| 301 | if (!equivalentAsOperands(LI->getCondition(), RI->getCondition())) { |
| 302 | if (Complain) Engine.log("branch conditions differ"); |
| 303 | return true; |
| 304 | } |
| 305 | if (TryUnify) tryUnify(LI->getSuccessor(1), RI->getSuccessor(1)); |
| 306 | } |
| 307 | if (TryUnify) tryUnify(LI->getSuccessor(0), RI->getSuccessor(0)); |
| 308 | return false; |
| 309 | |
| 310 | } else if (isa<SwitchInst>(L)) { |
| 311 | SwitchInst *LI = cast<SwitchInst>(L); |
| 312 | SwitchInst *RI = cast<SwitchInst>(R); |
| 313 | if (!equivalentAsOperands(LI->getCondition(), RI->getCondition())) { |
| 314 | if (Complain) Engine.log("switch conditions differ"); |
| 315 | return true; |
| 316 | } |
| 317 | if (TryUnify) tryUnify(LI->getDefaultDest(), RI->getDefaultDest()); |
| 318 | |
| 319 | bool Difference = false; |
| 320 | |
Stepan Dyatkovskiy | f4c261b | 2012-05-19 13:14:30 +0000 | [diff] [blame] | 321 | DenseMap<Constant*, BasicBlock*> LCases; |
Stepan Dyatkovskiy | c10fa6c | 2012-03-08 07:06:20 +0000 | [diff] [blame] | 322 | |
Stepan Dyatkovskiy | 3d3abe0 | 2012-03-11 06:09:17 +0000 | [diff] [blame] | 323 | for (SwitchInst::CaseIt I = LI->case_begin(), E = LI->case_end(); |
Stepan Dyatkovskiy | c10fa6c | 2012-03-08 07:06:20 +0000 | [diff] [blame] | 324 | I != E; ++I) |
Stepan Dyatkovskiy | f4c261b | 2012-05-19 13:14:30 +0000 | [diff] [blame] | 325 | LCases[I.getCaseValueEx()] = I.getCaseSuccessor(); |
Stepan Dyatkovskiy | c10fa6c | 2012-03-08 07:06:20 +0000 | [diff] [blame] | 326 | |
Stepan Dyatkovskiy | 3d3abe0 | 2012-03-11 06:09:17 +0000 | [diff] [blame] | 327 | for (SwitchInst::CaseIt I = RI->case_begin(), E = RI->case_end(); |
Stepan Dyatkovskiy | c10fa6c | 2012-03-08 07:06:20 +0000 | [diff] [blame] | 328 | I != E; ++I) { |
Stepan Dyatkovskiy | 0aa32d5 | 2012-05-29 12:26:47 +0000 | [diff] [blame] | 329 | IntegersSubset CaseValue = I.getCaseValueEx(); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 330 | BasicBlock *LCase = LCases[CaseValue]; |
| 331 | if (LCase) { |
Stepan Dyatkovskiy | c10fa6c | 2012-03-08 07:06:20 +0000 | [diff] [blame] | 332 | if (TryUnify) tryUnify(LCase, I.getCaseSuccessor()); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 333 | LCases.erase(CaseValue); |
John McCall | bd3c5ec | 2011-11-08 06:53:04 +0000 | [diff] [blame] | 334 | } else if (Complain || !Difference) { |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 335 | if (Complain) |
John McCall | 62dc1f3 | 2010-07-29 08:14:41 +0000 | [diff] [blame] | 336 | Engine.logf("right switch has extra case %r") << CaseValue; |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 337 | Difference = true; |
| 338 | } |
| 339 | } |
| 340 | if (!Difference) |
Stepan Dyatkovskiy | f4c261b | 2012-05-19 13:14:30 +0000 | [diff] [blame] | 341 | for (DenseMap<Constant*, BasicBlock*>::iterator |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 342 | I = LCases.begin(), E = LCases.end(); I != E; ++I) { |
| 343 | if (Complain) |
John McCall | 62dc1f3 | 2010-07-29 08:14:41 +0000 | [diff] [blame] | 344 | Engine.logf("left switch has extra case %l") << I->first; |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 345 | Difference = true; |
| 346 | } |
| 347 | return Difference; |
| 348 | } else if (isa<UnreachableInst>(L)) { |
| 349 | return false; |
| 350 | } |
| 351 | |
| 352 | if (L->getNumOperands() != R->getNumOperands()) { |
| 353 | if (Complain) Engine.log("instructions have different operand counts"); |
| 354 | return true; |
| 355 | } |
| 356 | |
| 357 | for (unsigned I = 0, E = L->getNumOperands(); I != E; ++I) { |
| 358 | Value *LO = L->getOperand(I), *RO = R->getOperand(I); |
| 359 | if (!equivalentAsOperands(LO, RO)) { |
John McCall | 62dc1f3 | 2010-07-29 08:14:41 +0000 | [diff] [blame] | 360 | if (Complain) Engine.logf("operands %l and %r differ") << LO << RO; |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 361 | return true; |
| 362 | } |
| 363 | } |
| 364 | |
| 365 | return false; |
| 366 | } |
| 367 | |
| 368 | bool equivalentAsOperands(Constant *L, Constant *R) { |
| 369 | // Use equality as a preliminary filter. |
| 370 | if (L == R) |
| 371 | return true; |
| 372 | |
| 373 | if (L->getValueID() != R->getValueID()) |
| 374 | return false; |
| 375 | |
| 376 | // Ask the engine about global values. |
| 377 | if (isa<GlobalValue>(L)) |
| 378 | return Engine.equivalentAsOperands(cast<GlobalValue>(L), |
| 379 | cast<GlobalValue>(R)); |
| 380 | |
| 381 | // Compare constant expressions structurally. |
| 382 | if (isa<ConstantExpr>(L)) |
| 383 | return equivalentAsOperands(cast<ConstantExpr>(L), |
| 384 | cast<ConstantExpr>(R)); |
| 385 | |
| 386 | // Nulls of the "same type" don't always actually have the same |
| 387 | // type; I don't know why. Just white-list them. |
| 388 | if (isa<ConstantPointerNull>(L)) |
| 389 | return true; |
| 390 | |
| 391 | // Block addresses only match if we've already encountered the |
| 392 | // block. FIXME: tentative matches? |
| 393 | if (isa<BlockAddress>(L)) |
| 394 | return Blocks[cast<BlockAddress>(L)->getBasicBlock()] |
| 395 | == cast<BlockAddress>(R)->getBasicBlock(); |
| 396 | |
| 397 | return false; |
| 398 | } |
| 399 | |
| 400 | bool equivalentAsOperands(ConstantExpr *L, ConstantExpr *R) { |
| 401 | if (L == R) |
| 402 | return true; |
| 403 | if (L->getOpcode() != R->getOpcode()) |
| 404 | return false; |
| 405 | |
| 406 | switch (L->getOpcode()) { |
| 407 | case Instruction::ICmp: |
| 408 | case Instruction::FCmp: |
| 409 | if (L->getPredicate() != R->getPredicate()) |
| 410 | return false; |
| 411 | break; |
| 412 | |
| 413 | case Instruction::GetElementPtr: |
| 414 | // FIXME: inbounds? |
| 415 | break; |
| 416 | |
| 417 | default: |
| 418 | break; |
| 419 | } |
| 420 | |
| 421 | if (L->getNumOperands() != R->getNumOperands()) |
| 422 | return false; |
| 423 | |
| 424 | for (unsigned I = 0, E = L->getNumOperands(); I != E; ++I) |
| 425 | if (!equivalentAsOperands(L->getOperand(I), R->getOperand(I))) |
| 426 | return false; |
| 427 | |
| 428 | return true; |
| 429 | } |
| 430 | |
| 431 | bool equivalentAsOperands(Value *L, Value *R) { |
| 432 | // Fall out if the values have different kind. |
| 433 | // This possibly shouldn't take priority over oracles. |
| 434 | if (L->getValueID() != R->getValueID()) |
| 435 | return false; |
| 436 | |
| 437 | // Value subtypes: Argument, Constant, Instruction, BasicBlock, |
| 438 | // InlineAsm, MDNode, MDString, PseudoSourceValue |
| 439 | |
| 440 | if (isa<Constant>(L)) |
| 441 | return equivalentAsOperands(cast<Constant>(L), cast<Constant>(R)); |
| 442 | |
| 443 | if (isa<Instruction>(L)) |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 444 | return Values[L] == R || TentativeValues.count(std::make_pair(L, R)); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 445 | |
| 446 | if (isa<Argument>(L)) |
| 447 | return Values[L] == R; |
| 448 | |
| 449 | if (isa<BasicBlock>(L)) |
| 450 | return Blocks[cast<BasicBlock>(L)] != R; |
| 451 | |
| 452 | // Pretend everything else is identical. |
| 453 | return true; |
| 454 | } |
| 455 | |
| 456 | // Avoid a gcc warning about accessing 'this' in an initializer. |
| 457 | FunctionDifferenceEngine *this_() { return this; } |
| 458 | |
| 459 | public: |
| 460 | FunctionDifferenceEngine(DifferenceEngine &Engine) : |
| 461 | Engine(Engine), Queue(QueueSorter(*this_())) {} |
| 462 | |
| 463 | void diff(Function *L, Function *R) { |
| 464 | if (L->arg_size() != R->arg_size()) |
| 465 | Engine.log("different argument counts"); |
| 466 | |
| 467 | // Map the arguments. |
| 468 | for (Function::arg_iterator |
| 469 | LI = L->arg_begin(), LE = L->arg_end(), |
| 470 | RI = R->arg_begin(), RE = R->arg_end(); |
| 471 | LI != LE && RI != RE; ++LI, ++RI) |
| 472 | Values[&*LI] = &*RI; |
| 473 | |
| 474 | tryUnify(&*L->begin(), &*R->begin()); |
| 475 | processQueue(); |
| 476 | } |
| 477 | }; |
| 478 | |
| 479 | struct DiffEntry { |
| 480 | DiffEntry() : Cost(0) {} |
| 481 | |
| 482 | unsigned Cost; |
| 483 | llvm::SmallVector<char, 8> Path; // actually of DifferenceEngine::DiffChange |
| 484 | }; |
| 485 | |
| 486 | bool FunctionDifferenceEngine::matchForBlockDiff(Instruction *L, |
| 487 | Instruction *R) { |
| 488 | return !diff(L, R, false, false); |
| 489 | } |
| 490 | |
| 491 | void FunctionDifferenceEngine::runBlockDiff(BasicBlock::iterator LStart, |
| 492 | BasicBlock::iterator RStart) { |
| 493 | BasicBlock::iterator LE = LStart->getParent()->end(); |
| 494 | BasicBlock::iterator RE = RStart->getParent()->end(); |
| 495 | |
| 496 | unsigned NL = std::distance(LStart, LE); |
| 497 | |
| 498 | SmallVector<DiffEntry, 20> Paths1(NL+1); |
| 499 | SmallVector<DiffEntry, 20> Paths2(NL+1); |
| 500 | |
| 501 | DiffEntry *Cur = Paths1.data(); |
| 502 | DiffEntry *Next = Paths2.data(); |
| 503 | |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 504 | const unsigned LeftCost = 2; |
| 505 | const unsigned RightCost = 2; |
| 506 | const unsigned MatchCost = 0; |
| 507 | |
| 508 | assert(TentativeValues.empty()); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 509 | |
| 510 | // Initialize the first column. |
| 511 | for (unsigned I = 0; I != NL+1; ++I) { |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 512 | Cur[I].Cost = I * LeftCost; |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 513 | for (unsigned J = 0; J != I; ++J) |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 514 | Cur[I].Path.push_back(DC_left); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 515 | } |
| 516 | |
| 517 | for (BasicBlock::iterator RI = RStart; RI != RE; ++RI) { |
| 518 | // Initialize the first row. |
| 519 | Next[0] = Cur[0]; |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 520 | Next[0].Cost += RightCost; |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 521 | Next[0].Path.push_back(DC_right); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 522 | |
| 523 | unsigned Index = 1; |
| 524 | for (BasicBlock::iterator LI = LStart; LI != LE; ++LI, ++Index) { |
| 525 | if (matchForBlockDiff(&*LI, &*RI)) { |
| 526 | Next[Index] = Cur[Index-1]; |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 527 | Next[Index].Cost += MatchCost; |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 528 | Next[Index].Path.push_back(DC_match); |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 529 | TentativeValues.insert(std::make_pair(&*LI, &*RI)); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 530 | } else if (Next[Index-1].Cost <= Cur[Index].Cost) { |
| 531 | Next[Index] = Next[Index-1]; |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 532 | Next[Index].Cost += LeftCost; |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 533 | Next[Index].Path.push_back(DC_left); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 534 | } else { |
| 535 | Next[Index] = Cur[Index]; |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 536 | Next[Index].Cost += RightCost; |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 537 | Next[Index].Path.push_back(DC_right); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 538 | } |
| 539 | } |
| 540 | |
| 541 | std::swap(Cur, Next); |
| 542 | } |
| 543 | |
John McCall | 82bd5ea | 2010-07-29 09:20:34 +0000 | [diff] [blame] | 544 | // We don't need the tentative values anymore; everything from here |
| 545 | // on out should be non-tentative. |
| 546 | TentativeValues.clear(); |
| 547 | |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 548 | SmallVectorImpl<char> &Path = Cur[NL].Path; |
| 549 | BasicBlock::iterator LI = LStart, RI = RStart; |
| 550 | |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 551 | DiffLogBuilder Diff(Engine.getConsumer()); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 552 | |
| 553 | // Drop trailing matches. |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 554 | while (Path.back() == DC_match) |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 555 | Path.pop_back(); |
| 556 | |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 557 | // Skip leading matches. |
| 558 | SmallVectorImpl<char>::iterator |
| 559 | PI = Path.begin(), PE = Path.end(); |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 560 | while (PI != PE && *PI == DC_match) { |
John McCall | 82bd5ea | 2010-07-29 09:20:34 +0000 | [diff] [blame] | 561 | unify(&*LI, &*RI); |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 562 | ++PI, ++LI, ++RI; |
John McCall | 82bd5ea | 2010-07-29 09:20:34 +0000 | [diff] [blame] | 563 | } |
John McCall | dfb44ac | 2010-07-29 08:53:59 +0000 | [diff] [blame] | 564 | |
| 565 | for (; PI != PE; ++PI) { |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 566 | switch (static_cast<DiffChange>(*PI)) { |
| 567 | case DC_match: |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 568 | assert(LI != LE && RI != RE); |
| 569 | { |
| 570 | Instruction *L = &*LI, *R = &*RI; |
John McCall | 82bd5ea | 2010-07-29 09:20:34 +0000 | [diff] [blame] | 571 | unify(L, R); |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 572 | Diff.addMatch(L, R); |
| 573 | } |
| 574 | ++LI; ++RI; |
| 575 | break; |
| 576 | |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 577 | case DC_left: |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 578 | assert(LI != LE); |
| 579 | Diff.addLeft(&*LI); |
| 580 | ++LI; |
| 581 | break; |
| 582 | |
Renato Golin | 7d4fc4f | 2011-03-14 22:22:46 +0000 | [diff] [blame] | 583 | case DC_right: |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 584 | assert(RI != RE); |
| 585 | Diff.addRight(&*RI); |
| 586 | ++RI; |
| 587 | break; |
| 588 | } |
| 589 | } |
| 590 | |
John McCall | 82bd5ea | 2010-07-29 09:20:34 +0000 | [diff] [blame] | 591 | // Finishing unifying and complaining about the tails of the block, |
| 592 | // which should be matches all the way through. |
| 593 | while (LI != LE) { |
| 594 | assert(RI != RE); |
| 595 | unify(&*LI, &*RI); |
| 596 | ++LI, ++RI; |
| 597 | } |
John McCall | b82b433 | 2010-08-24 09:16:51 +0000 | [diff] [blame] | 598 | |
| 599 | // If the terminators have different kinds, but one is an invoke and the |
| 600 | // other is an unconditional branch immediately following a call, unify |
| 601 | // the results and the destinations. |
| 602 | TerminatorInst *LTerm = LStart->getParent()->getTerminator(); |
| 603 | TerminatorInst *RTerm = RStart->getParent()->getTerminator(); |
| 604 | if (isa<BranchInst>(LTerm) && isa<InvokeInst>(RTerm)) { |
| 605 | if (cast<BranchInst>(LTerm)->isConditional()) return; |
| 606 | BasicBlock::iterator I = LTerm; |
| 607 | if (I == LStart->getParent()->begin()) return; |
| 608 | --I; |
| 609 | if (!isa<CallInst>(*I)) return; |
| 610 | CallInst *LCall = cast<CallInst>(&*I); |
| 611 | InvokeInst *RInvoke = cast<InvokeInst>(RTerm); |
| 612 | if (!equivalentAsOperands(LCall->getCalledValue(), RInvoke->getCalledValue())) |
| 613 | return; |
| 614 | if (!LCall->use_empty()) |
| 615 | Values[LCall] = RInvoke; |
| 616 | tryUnify(LTerm->getSuccessor(0), RInvoke->getNormalDest()); |
| 617 | } else if (isa<InvokeInst>(LTerm) && isa<BranchInst>(RTerm)) { |
| 618 | if (cast<BranchInst>(RTerm)->isConditional()) return; |
| 619 | BasicBlock::iterator I = RTerm; |
| 620 | if (I == RStart->getParent()->begin()) return; |
| 621 | --I; |
| 622 | if (!isa<CallInst>(*I)) return; |
| 623 | CallInst *RCall = cast<CallInst>(I); |
| 624 | InvokeInst *LInvoke = cast<InvokeInst>(LTerm); |
| 625 | if (!equivalentAsOperands(LInvoke->getCalledValue(), RCall->getCalledValue())) |
| 626 | return; |
| 627 | if (!LInvoke->use_empty()) |
| 628 | Values[LInvoke] = RCall; |
| 629 | tryUnify(LInvoke->getNormalDest(), RTerm->getSuccessor(0)); |
| 630 | } |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 631 | } |
| 632 | |
| 633 | } |
| 634 | |
David Blaikie | 2d24e2a | 2011-12-20 02:50:00 +0000 | [diff] [blame] | 635 | void DifferenceEngine::Oracle::anchor() { } |
| 636 | |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 637 | void DifferenceEngine::diff(Function *L, Function *R) { |
| 638 | Context C(*this, L, R); |
| 639 | |
| 640 | // FIXME: types |
| 641 | // FIXME: attributes and CC |
| 642 | // FIXME: parameter attributes |
| 643 | |
| 644 | // If both are declarations, we're done. |
| 645 | if (L->empty() && R->empty()) |
| 646 | return; |
| 647 | else if (L->empty()) |
| 648 | log("left function is declaration, right function is definition"); |
| 649 | else if (R->empty()) |
| 650 | log("right function is declaration, left function is definition"); |
| 651 | else |
| 652 | FunctionDifferenceEngine(*this).diff(L, R); |
| 653 | } |
| 654 | |
| 655 | void DifferenceEngine::diff(Module *L, Module *R) { |
| 656 | StringSet<> LNames; |
| 657 | SmallVector<std::pair<Function*,Function*>, 20> Queue; |
| 658 | |
| 659 | for (Module::iterator I = L->begin(), E = L->end(); I != E; ++I) { |
| 660 | Function *LFn = &*I; |
| 661 | LNames.insert(LFn->getName()); |
| 662 | |
| 663 | if (Function *RFn = R->getFunction(LFn->getName())) |
| 664 | Queue.push_back(std::make_pair(LFn, RFn)); |
| 665 | else |
John McCall | 62dc1f3 | 2010-07-29 08:14:41 +0000 | [diff] [blame] | 666 | logf("function %l exists only in left module") << LFn; |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 667 | } |
| 668 | |
| 669 | for (Module::iterator I = R->begin(), E = R->end(); I != E; ++I) { |
| 670 | Function *RFn = &*I; |
| 671 | if (!LNames.count(RFn->getName())) |
John McCall | 62dc1f3 | 2010-07-29 08:14:41 +0000 | [diff] [blame] | 672 | logf("function %r exists only in right module") << RFn; |
John McCall | 3dd706b | 2010-07-29 07:53:27 +0000 | [diff] [blame] | 673 | } |
| 674 | |
| 675 | for (SmallVectorImpl<std::pair<Function*,Function*> >::iterator |
| 676 | I = Queue.begin(), E = Queue.end(); I != E; ++I) |
| 677 | diff(I->first, I->second); |
| 678 | } |
| 679 | |
| 680 | bool DifferenceEngine::equivalentAsOperands(GlobalValue *L, GlobalValue *R) { |
| 681 | if (globalValueOracle) return (*globalValueOracle)(L, R); |
| 682 | return L->getName() == R->getName(); |
| 683 | } |