1 //===- Miscompilation.cpp - Debug program miscompilations -----------------===// 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 // 10 // This file implements optimizer and code generation miscompilation debugging 11 // support. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "BugDriver.h" 16 #include "ListReducer.h" 17 #include "ToolRunner.h" 18 #include "llvm/Config/config.h" // for HAVE_LINK_R 19 #include "llvm/IR/Constants.h" 20 #include "llvm/IR/DerivedTypes.h" 21 #include "llvm/IR/Instructions.h" 22 #include "llvm/IR/Module.h" 23 #include "llvm/IR/Verifier.h" 24 #include "llvm/Linker/Linker.h" 25 #include "llvm/Pass.h" 26 #include "llvm/Support/CommandLine.h" 27 #include "llvm/Support/FileUtilities.h" 28 #include "llvm/Transforms/Utils/Cloning.h" 29 using namespace llvm; 30 31 namespace llvm { 32 extern cl::opt<std::string> OutputPrefix; 33 extern cl::list<std::string> InputArgv; 34 } 35 36 namespace { 37 static llvm::cl::opt<bool> 38 DisableLoopExtraction("disable-loop-extraction", 39 cl::desc("Don't extract loops when searching for miscompilations"), 40 cl::init(false)); 41 static llvm::cl::opt<bool> 42 DisableBlockExtraction("disable-block-extraction", 43 cl::desc("Don't extract blocks when searching for miscompilations"), 44 cl::init(false)); 45 46 class ReduceMiscompilingPasses : public ListReducer<std::string> { 47 BugDriver &BD; 48 public: 49 ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {} 50 51 TestResult doTest(std::vector<std::string> &Prefix, 52 std::vector<std::string> &Suffix, 53 std::string &Error) override; 54 }; 55 } 56 57 /// TestResult - After passes have been split into a test group and a control 58 /// group, see if they still break the program. 59 /// 60 ReduceMiscompilingPasses::TestResult 61 ReduceMiscompilingPasses::doTest(std::vector<std::string> &Prefix, 62 std::vector<std::string> &Suffix, 63 std::string &Error) { 64 // First, run the program with just the Suffix passes. If it is still broken 65 // with JUST the kept passes, discard the prefix passes. 66 outs() << "Checking to see if '" << getPassesString(Suffix) 67 << "' compiles correctly: "; 68 69 std::string BitcodeResult; 70 if (BD.runPasses(BD.getProgram(), Suffix, BitcodeResult, false/*delete*/, 71 true/*quiet*/)) { 72 errs() << " Error running this sequence of passes" 73 << " on the input program!\n"; 74 BD.setPassesToRun(Suffix); 75 BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false); 76 exit(BD.debugOptimizerCrash()); 77 } 78 79 // Check to see if the finished program matches the reference output... 80 bool Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", 81 true /*delete bitcode*/, &Error); 82 if (!Error.empty()) 83 return InternalError; 84 if (Diff) { 85 outs() << " nope.\n"; 86 if (Suffix.empty()) { 87 errs() << BD.getToolName() << ": I'm confused: the test fails when " 88 << "no passes are run, nondeterministic program?\n"; 89 exit(1); 90 } 91 return KeepSuffix; // Miscompilation detected! 92 } 93 outs() << " yup.\n"; // No miscompilation! 94 95 if (Prefix.empty()) return NoFailure; 96 97 // Next, see if the program is broken if we run the "prefix" passes first, 98 // then separately run the "kept" passes. 99 outs() << "Checking to see if '" << getPassesString(Prefix) 100 << "' compiles correctly: "; 101 102 // If it is not broken with the kept passes, it's possible that the prefix 103 // passes must be run before the kept passes to break it. If the program 104 // WORKS after the prefix passes, but then fails if running the prefix AND 105 // kept passes, we can update our bitcode file to include the result of the 106 // prefix passes, then discard the prefix passes. 107 // 108 if (BD.runPasses(BD.getProgram(), Prefix, BitcodeResult, false/*delete*/, 109 true/*quiet*/)) { 110 errs() << " Error running this sequence of passes" 111 << " on the input program!\n"; 112 BD.setPassesToRun(Prefix); 113 BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false); 114 exit(BD.debugOptimizerCrash()); 115 } 116 117 // If the prefix maintains the predicate by itself, only keep the prefix! 118 Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", false, &Error); 119 if (!Error.empty()) 120 return InternalError; 121 if (Diff) { 122 outs() << " nope.\n"; 123 sys::fs::remove(BitcodeResult); 124 return KeepPrefix; 125 } 126 outs() << " yup.\n"; // No miscompilation! 127 128 // Ok, so now we know that the prefix passes work, try running the suffix 129 // passes on the result of the prefix passes. 130 // 131 std::unique_ptr<Module> PrefixOutput( 132 ParseInputFile(BitcodeResult, BD.getContext())); 133 if (!PrefixOutput) { 134 errs() << BD.getToolName() << ": Error reading bitcode file '" 135 << BitcodeResult << "'!\n"; 136 exit(1); 137 } 138 sys::fs::remove(BitcodeResult); 139 140 // Don't check if there are no passes in the suffix. 141 if (Suffix.empty()) 142 return NoFailure; 143 144 outs() << "Checking to see if '" << getPassesString(Suffix) 145 << "' passes compile correctly after the '" 146 << getPassesString(Prefix) << "' passes: "; 147 148 std::unique_ptr<Module> OriginalInput( 149 BD.swapProgramIn(PrefixOutput.release())); 150 if (BD.runPasses(BD.getProgram(), Suffix, BitcodeResult, false/*delete*/, 151 true/*quiet*/)) { 152 errs() << " Error running this sequence of passes" 153 << " on the input program!\n"; 154 BD.setPassesToRun(Suffix); 155 BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false); 156 exit(BD.debugOptimizerCrash()); 157 } 158 159 // Run the result... 160 Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", 161 true /*delete bitcode*/, &Error); 162 if (!Error.empty()) 163 return InternalError; 164 if (Diff) { 165 outs() << " nope.\n"; 166 return KeepSuffix; 167 } 168 169 // Otherwise, we must not be running the bad pass anymore. 170 outs() << " yup.\n"; // No miscompilation! 171 // Restore orig program & free test. 172 delete BD.swapProgramIn(OriginalInput.release()); 173 return NoFailure; 174 } 175 176 namespace { 177 class ReduceMiscompilingFunctions : public ListReducer<Function*> { 178 BugDriver &BD; 179 bool (*TestFn)(BugDriver &, Module *, Module *, std::string &); 180 public: 181 ReduceMiscompilingFunctions(BugDriver &bd, 182 bool (*F)(BugDriver &, Module *, Module *, 183 std::string &)) 184 : BD(bd), TestFn(F) {} 185 186 TestResult doTest(std::vector<Function*> &Prefix, 187 std::vector<Function*> &Suffix, 188 std::string &Error) override { 189 if (!Suffix.empty()) { 190 bool Ret = TestFuncs(Suffix, Error); 191 if (!Error.empty()) 192 return InternalError; 193 if (Ret) 194 return KeepSuffix; 195 } 196 if (!Prefix.empty()) { 197 bool Ret = TestFuncs(Prefix, Error); 198 if (!Error.empty()) 199 return InternalError; 200 if (Ret) 201 return KeepPrefix; 202 } 203 return NoFailure; 204 } 205 206 bool TestFuncs(const std::vector<Function*> &Prefix, std::string &Error); 207 }; 208 } 209 210 /// TestMergedProgram - Given two modules, link them together and run the 211 /// program, checking to see if the program matches the diff. If there is 212 /// an error, return NULL. If not, return the merged module. The Broken argument 213 /// will be set to true if the output is different. If the DeleteInputs 214 /// argument is set to true then this function deletes both input 215 /// modules before it returns. 216 /// 217 static Module *TestMergedProgram(const BugDriver &BD, Module *M1, Module *M2, 218 bool DeleteInputs, std::string &Error, 219 bool &Broken) { 220 // Link the two portions of the program back to together. 221 std::string ErrorMsg; 222 if (!DeleteInputs) { 223 M1 = CloneModule(M1); 224 M2 = CloneModule(M2); 225 } 226 if (Linker::LinkModules(M1, M2, Linker::DestroySource, &ErrorMsg)) { 227 errs() << BD.getToolName() << ": Error linking modules together:" 228 << ErrorMsg << '\n'; 229 exit(1); 230 } 231 delete M2; // We are done with this module. 232 233 // Execute the program. 234 Broken = BD.diffProgram(M1, "", "", false, &Error); 235 if (!Error.empty()) { 236 // Delete the linked module 237 delete M1; 238 return nullptr; 239 } 240 return M1; 241 } 242 243 /// TestFuncs - split functions in a Module into two groups: those that are 244 /// under consideration for miscompilation vs. those that are not, and test 245 /// accordingly. Each group of functions becomes a separate Module. 246 /// 247 bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs, 248 std::string &Error) { 249 // Test to see if the function is misoptimized if we ONLY run it on the 250 // functions listed in Funcs. 251 outs() << "Checking to see if the program is misoptimized when " 252 << (Funcs.size()==1 ? "this function is" : "these functions are") 253 << " run through the pass" 254 << (BD.getPassesToRun().size() == 1 ? "" : "es") << ":"; 255 PrintFunctionList(Funcs); 256 outs() << '\n'; 257 258 // Create a clone for two reasons: 259 // * If the optimization passes delete any function, the deleted function 260 // will be in the clone and Funcs will still point to valid memory 261 // * If the optimization passes use interprocedural information to break 262 // a function, we want to continue with the original function. Otherwise 263 // we can conclude that a function triggers the bug when in fact one 264 // needs a larger set of original functions to do so. 265 ValueToValueMapTy VMap; 266 Module *Clone = CloneModule(BD.getProgram(), VMap); 267 Module *Orig = BD.swapProgramIn(Clone); 268 269 std::vector<Function*> FuncsOnClone; 270 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) { 271 Function *F = cast<Function>(VMap[Funcs[i]]); 272 FuncsOnClone.push_back(F); 273 } 274 275 // Split the module into the two halves of the program we want. 276 VMap.clear(); 277 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap); 278 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, FuncsOnClone, 279 VMap); 280 281 // Run the predicate, note that the predicate will delete both input modules. 282 bool Broken = TestFn(BD, ToOptimize, ToNotOptimize, Error); 283 284 delete BD.swapProgramIn(Orig); 285 286 return Broken; 287 } 288 289 /// DisambiguateGlobalSymbols - Give anonymous global values names. 290 /// 291 static void DisambiguateGlobalSymbols(Module *M) { 292 for (Module::global_iterator I = M->global_begin(), E = M->global_end(); 293 I != E; ++I) 294 if (!I->hasName()) 295 I->setName("anon_global"); 296 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) 297 if (!I->hasName()) 298 I->setName("anon_fn"); 299 } 300 301 /// ExtractLoops - Given a reduced list of functions that still exposed the bug, 302 /// check to see if we can extract the loops in the region without obscuring the 303 /// bug. If so, it reduces the amount of code identified. 304 /// 305 static bool ExtractLoops(BugDriver &BD, 306 bool (*TestFn)(BugDriver &, Module *, Module *, 307 std::string &), 308 std::vector<Function*> &MiscompiledFunctions, 309 std::string &Error) { 310 bool MadeChange = false; 311 while (1) { 312 if (BugpointIsInterrupted) return MadeChange; 313 314 ValueToValueMapTy VMap; 315 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap); 316 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, 317 MiscompiledFunctions, 318 VMap); 319 Module *ToOptimizeLoopExtracted = BD.ExtractLoop(ToOptimize); 320 if (!ToOptimizeLoopExtracted) { 321 // If the loop extractor crashed or if there were no extractible loops, 322 // then this chapter of our odyssey is over with. 323 delete ToNotOptimize; 324 delete ToOptimize; 325 return MadeChange; 326 } 327 328 errs() << "Extracted a loop from the breaking portion of the program.\n"; 329 330 // Bugpoint is intentionally not very trusting of LLVM transformations. In 331 // particular, we're not going to assume that the loop extractor works, so 332 // we're going to test the newly loop extracted program to make sure nothing 333 // has broken. If something broke, then we'll inform the user and stop 334 // extraction. 335 AbstractInterpreter *AI = BD.switchToSafeInterpreter(); 336 bool Failure; 337 Module *New = TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize, 338 false, Error, Failure); 339 if (!New) 340 return false; 341 342 // Delete the original and set the new program. 343 Module *Old = BD.swapProgramIn(New); 344 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) 345 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]); 346 delete Old; 347 348 if (Failure) { 349 BD.switchToInterpreter(AI); 350 351 // Merged program doesn't work anymore! 352 errs() << " *** ERROR: Loop extraction broke the program. :(" 353 << " Please report a bug!\n"; 354 errs() << " Continuing on with un-loop-extracted version.\n"; 355 356 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-tno.bc", 357 ToNotOptimize); 358 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to.bc", 359 ToOptimize); 360 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to-le.bc", 361 ToOptimizeLoopExtracted); 362 363 errs() << "Please submit the " 364 << OutputPrefix << "-loop-extract-fail-*.bc files.\n"; 365 delete ToOptimize; 366 delete ToNotOptimize; 367 delete ToOptimizeLoopExtracted; 368 return MadeChange; 369 } 370 delete ToOptimize; 371 BD.switchToInterpreter(AI); 372 373 outs() << " Testing after loop extraction:\n"; 374 // Clone modules, the tester function will free them. 375 Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted, VMap); 376 Module *TNOBackup = CloneModule(ToNotOptimize, VMap); 377 378 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) 379 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]); 380 381 Failure = TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize, Error); 382 if (!Error.empty()) 383 return false; 384 385 ToOptimizeLoopExtracted = TOLEBackup; 386 ToNotOptimize = TNOBackup; 387 388 if (!Failure) { 389 outs() << "*** Loop extraction masked the problem. Undoing.\n"; 390 // If the program is not still broken, then loop extraction did something 391 // that masked the error. Stop loop extraction now. 392 393 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions; 394 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) { 395 Function *F = MiscompiledFunctions[i]; 396 MisCompFunctions.push_back(std::make_pair(F->getName(), 397 F->getFunctionType())); 398 } 399 400 std::string ErrorMsg; 401 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted, 402 Linker::DestroySource, &ErrorMsg)){ 403 errs() << BD.getToolName() << ": Error linking modules together:" 404 << ErrorMsg << '\n'; 405 exit(1); 406 } 407 408 MiscompiledFunctions.clear(); 409 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) { 410 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first); 411 412 assert(NewF && "Function not found??"); 413 MiscompiledFunctions.push_back(NewF); 414 } 415 416 delete ToOptimizeLoopExtracted; 417 BD.setNewProgram(ToNotOptimize); 418 return MadeChange; 419 } 420 421 outs() << "*** Loop extraction successful!\n"; 422 423 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions; 424 for (Module::iterator I = ToOptimizeLoopExtracted->begin(), 425 E = ToOptimizeLoopExtracted->end(); I != E; ++I) 426 if (!I->isDeclaration()) 427 MisCompFunctions.push_back(std::make_pair(I->getName(), 428 I->getFunctionType())); 429 430 // Okay, great! Now we know that we extracted a loop and that loop 431 // extraction both didn't break the program, and didn't mask the problem. 432 // Replace the current program with the loop extracted version, and try to 433 // extract another loop. 434 std::string ErrorMsg; 435 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted, 436 Linker::DestroySource, &ErrorMsg)){ 437 errs() << BD.getToolName() << ": Error linking modules together:" 438 << ErrorMsg << '\n'; 439 exit(1); 440 } 441 delete ToOptimizeLoopExtracted; 442 443 // All of the Function*'s in the MiscompiledFunctions list are in the old 444 // module. Update this list to include all of the functions in the 445 // optimized and loop extracted module. 446 MiscompiledFunctions.clear(); 447 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) { 448 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first); 449 450 assert(NewF && "Function not found??"); 451 MiscompiledFunctions.push_back(NewF); 452 } 453 454 BD.setNewProgram(ToNotOptimize); 455 MadeChange = true; 456 } 457 } 458 459 namespace { 460 class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> { 461 BugDriver &BD; 462 bool (*TestFn)(BugDriver &, Module *, Module *, std::string &); 463 std::vector<Function*> FunctionsBeingTested; 464 public: 465 ReduceMiscompiledBlocks(BugDriver &bd, 466 bool (*F)(BugDriver &, Module *, Module *, 467 std::string &), 468 const std::vector<Function*> &Fns) 469 : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {} 470 471 TestResult doTest(std::vector<BasicBlock*> &Prefix, 472 std::vector<BasicBlock*> &Suffix, 473 std::string &Error) override { 474 if (!Suffix.empty()) { 475 bool Ret = TestFuncs(Suffix, Error); 476 if (!Error.empty()) 477 return InternalError; 478 if (Ret) 479 return KeepSuffix; 480 } 481 if (!Prefix.empty()) { 482 bool Ret = TestFuncs(Prefix, Error); 483 if (!Error.empty()) 484 return InternalError; 485 if (Ret) 486 return KeepPrefix; 487 } 488 return NoFailure; 489 } 490 491 bool TestFuncs(const std::vector<BasicBlock*> &BBs, std::string &Error); 492 }; 493 } 494 495 /// TestFuncs - Extract all blocks for the miscompiled functions except for the 496 /// specified blocks. If the problem still exists, return true. 497 /// 498 bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs, 499 std::string &Error) { 500 // Test to see if the function is misoptimized if we ONLY run it on the 501 // functions listed in Funcs. 502 outs() << "Checking to see if the program is misoptimized when all "; 503 if (!BBs.empty()) { 504 outs() << "but these " << BBs.size() << " blocks are extracted: "; 505 for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i) 506 outs() << BBs[i]->getName() << " "; 507 if (BBs.size() > 10) outs() << "..."; 508 } else { 509 outs() << "blocks are extracted."; 510 } 511 outs() << '\n'; 512 513 // Split the module into the two halves of the program we want. 514 ValueToValueMapTy VMap; 515 Module *Clone = CloneModule(BD.getProgram(), VMap); 516 Module *Orig = BD.swapProgramIn(Clone); 517 std::vector<Function*> FuncsOnClone; 518 std::vector<BasicBlock*> BBsOnClone; 519 for (unsigned i = 0, e = FunctionsBeingTested.size(); i != e; ++i) { 520 Function *F = cast<Function>(VMap[FunctionsBeingTested[i]]); 521 FuncsOnClone.push_back(F); 522 } 523 for (unsigned i = 0, e = BBs.size(); i != e; ++i) { 524 BasicBlock *BB = cast<BasicBlock>(VMap[BBs[i]]); 525 BBsOnClone.push_back(BB); 526 } 527 VMap.clear(); 528 529 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap); 530 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, 531 FuncsOnClone, 532 VMap); 533 534 // Try the extraction. If it doesn't work, then the block extractor crashed 535 // or something, in which case bugpoint can't chase down this possibility. 536 if (Module *New = BD.ExtractMappedBlocksFromModule(BBsOnClone, ToOptimize)) { 537 delete ToOptimize; 538 // Run the predicate, 539 // note that the predicate will delete both input modules. 540 bool Ret = TestFn(BD, New, ToNotOptimize, Error); 541 delete BD.swapProgramIn(Orig); 542 return Ret; 543 } 544 delete BD.swapProgramIn(Orig); 545 delete ToOptimize; 546 delete ToNotOptimize; 547 return false; 548 } 549 550 551 /// ExtractBlocks - Given a reduced list of functions that still expose the bug, 552 /// extract as many basic blocks from the region as possible without obscuring 553 /// the bug. 554 /// 555 static bool ExtractBlocks(BugDriver &BD, 556 bool (*TestFn)(BugDriver &, Module *, Module *, 557 std::string &), 558 std::vector<Function*> &MiscompiledFunctions, 559 std::string &Error) { 560 if (BugpointIsInterrupted) return false; 561 562 std::vector<BasicBlock*> Blocks; 563 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) 564 for (Function::iterator I = MiscompiledFunctions[i]->begin(), 565 E = MiscompiledFunctions[i]->end(); I != E; ++I) 566 Blocks.push_back(I); 567 568 // Use the list reducer to identify blocks that can be extracted without 569 // obscuring the bug. The Blocks list will end up containing blocks that must 570 // be retained from the original program. 571 unsigned OldSize = Blocks.size(); 572 573 // Check to see if all blocks are extractible first. 574 bool Ret = ReduceMiscompiledBlocks(BD, TestFn, MiscompiledFunctions) 575 .TestFuncs(std::vector<BasicBlock*>(), Error); 576 if (!Error.empty()) 577 return false; 578 if (Ret) { 579 Blocks.clear(); 580 } else { 581 ReduceMiscompiledBlocks(BD, TestFn, 582 MiscompiledFunctions).reduceList(Blocks, Error); 583 if (!Error.empty()) 584 return false; 585 if (Blocks.size() == OldSize) 586 return false; 587 } 588 589 ValueToValueMapTy VMap; 590 Module *ProgClone = CloneModule(BD.getProgram(), VMap); 591 Module *ToExtract = SplitFunctionsOutOfModule(ProgClone, 592 MiscompiledFunctions, 593 VMap); 594 Module *Extracted = BD.ExtractMappedBlocksFromModule(Blocks, ToExtract); 595 if (!Extracted) { 596 // Weird, extraction should have worked. 597 errs() << "Nondeterministic problem extracting blocks??\n"; 598 delete ProgClone; 599 delete ToExtract; 600 return false; 601 } 602 603 // Otherwise, block extraction succeeded. Link the two program fragments back 604 // together. 605 delete ToExtract; 606 607 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions; 608 for (Module::iterator I = Extracted->begin(), E = Extracted->end(); 609 I != E; ++I) 610 if (!I->isDeclaration()) 611 MisCompFunctions.push_back(std::make_pair(I->getName(), 612 I->getFunctionType())); 613 614 std::string ErrorMsg; 615 if (Linker::LinkModules(ProgClone, Extracted, Linker::DestroySource, 616 &ErrorMsg)) { 617 errs() << BD.getToolName() << ": Error linking modules together:" 618 << ErrorMsg << '\n'; 619 exit(1); 620 } 621 delete Extracted; 622 623 // Set the new program and delete the old one. 624 BD.setNewProgram(ProgClone); 625 626 // Update the list of miscompiled functions. 627 MiscompiledFunctions.clear(); 628 629 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) { 630 Function *NewF = ProgClone->getFunction(MisCompFunctions[i].first); 631 assert(NewF && "Function not found??"); 632 MiscompiledFunctions.push_back(NewF); 633 } 634 635 return true; 636 } 637 638 639 /// DebugAMiscompilation - This is a generic driver to narrow down 640 /// miscompilations, either in an optimization or a code generator. 641 /// 642 static std::vector<Function*> 643 DebugAMiscompilation(BugDriver &BD, 644 bool (*TestFn)(BugDriver &, Module *, Module *, 645 std::string &), 646 std::string &Error) { 647 // Okay, now that we have reduced the list of passes which are causing the 648 // failure, see if we can pin down which functions are being 649 // miscompiled... first build a list of all of the non-external functions in 650 // the program. 651 std::vector<Function*> MiscompiledFunctions; 652 Module *Prog = BD.getProgram(); 653 for (Module::iterator I = Prog->begin(), E = Prog->end(); I != E; ++I) 654 if (!I->isDeclaration()) 655 MiscompiledFunctions.push_back(I); 656 657 // Do the reduction... 658 if (!BugpointIsInterrupted) 659 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions, 660 Error); 661 if (!Error.empty()) { 662 errs() << "\n***Cannot reduce functions: "; 663 return MiscompiledFunctions; 664 } 665 outs() << "\n*** The following function" 666 << (MiscompiledFunctions.size() == 1 ? " is" : "s are") 667 << " being miscompiled: "; 668 PrintFunctionList(MiscompiledFunctions); 669 outs() << '\n'; 670 671 // See if we can rip any loops out of the miscompiled functions and still 672 // trigger the problem. 673 674 if (!BugpointIsInterrupted && !DisableLoopExtraction) { 675 bool Ret = ExtractLoops(BD, TestFn, MiscompiledFunctions, Error); 676 if (!Error.empty()) 677 return MiscompiledFunctions; 678 if (Ret) { 679 // Okay, we extracted some loops and the problem still appears. See if 680 // we can eliminate some of the created functions from being candidates. 681 DisambiguateGlobalSymbols(BD.getProgram()); 682 683 // Do the reduction... 684 if (!BugpointIsInterrupted) 685 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions, 686 Error); 687 if (!Error.empty()) 688 return MiscompiledFunctions; 689 690 outs() << "\n*** The following function" 691 << (MiscompiledFunctions.size() == 1 ? " is" : "s are") 692 << " being miscompiled: "; 693 PrintFunctionList(MiscompiledFunctions); 694 outs() << '\n'; 695 } 696 } 697 698 if (!BugpointIsInterrupted && !DisableBlockExtraction) { 699 bool Ret = ExtractBlocks(BD, TestFn, MiscompiledFunctions, Error); 700 if (!Error.empty()) 701 return MiscompiledFunctions; 702 if (Ret) { 703 // Okay, we extracted some blocks and the problem still appears. See if 704 // we can eliminate some of the created functions from being candidates. 705 DisambiguateGlobalSymbols(BD.getProgram()); 706 707 // Do the reduction... 708 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions, 709 Error); 710 if (!Error.empty()) 711 return MiscompiledFunctions; 712 713 outs() << "\n*** The following function" 714 << (MiscompiledFunctions.size() == 1 ? " is" : "s are") 715 << " being miscompiled: "; 716 PrintFunctionList(MiscompiledFunctions); 717 outs() << '\n'; 718 } 719 } 720 721 return MiscompiledFunctions; 722 } 723 724 /// TestOptimizer - This is the predicate function used to check to see if the 725 /// "Test" portion of the program is misoptimized. If so, return true. In any 726 /// case, both module arguments are deleted. 727 /// 728 static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe, 729 std::string &Error) { 730 // Run the optimization passes on ToOptimize, producing a transformed version 731 // of the functions being tested. 732 outs() << " Optimizing functions being tested: "; 733 Module *Optimized = BD.runPassesOn(Test, BD.getPassesToRun(), 734 /*AutoDebugCrashes*/true); 735 outs() << "done.\n"; 736 delete Test; 737 738 outs() << " Checking to see if the merged program executes correctly: "; 739 bool Broken; 740 Module *New = TestMergedProgram(BD, Optimized, Safe, true, Error, Broken); 741 if (New) { 742 outs() << (Broken ? " nope.\n" : " yup.\n"); 743 // Delete the original and set the new program. 744 delete BD.swapProgramIn(New); 745 } 746 return Broken; 747 } 748 749 750 /// debugMiscompilation - This method is used when the passes selected are not 751 /// crashing, but the generated output is semantically different from the 752 /// input. 753 /// 754 void BugDriver::debugMiscompilation(std::string *Error) { 755 // Make sure something was miscompiled... 756 if (!BugpointIsInterrupted) 757 if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun, *Error)) { 758 if (Error->empty()) 759 errs() << "*** Optimized program matches reference output! No problem" 760 << " detected...\nbugpoint can't help you with your problem!\n"; 761 return; 762 } 763 764 outs() << "\n*** Found miscompiling pass" 765 << (getPassesToRun().size() == 1 ? "" : "es") << ": " 766 << getPassesString(getPassesToRun()) << '\n'; 767 EmitProgressBitcode(Program, "passinput"); 768 769 std::vector<Function *> MiscompiledFunctions = 770 DebugAMiscompilation(*this, TestOptimizer, *Error); 771 if (!Error->empty()) 772 return; 773 774 // Output a bunch of bitcode files for the user... 775 outs() << "Outputting reduced bitcode files which expose the problem:\n"; 776 ValueToValueMapTy VMap; 777 Module *ToNotOptimize = CloneModule(getProgram(), VMap); 778 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, 779 MiscompiledFunctions, 780 VMap); 781 782 outs() << " Non-optimized portion: "; 783 EmitProgressBitcode(ToNotOptimize, "tonotoptimize", true); 784 delete ToNotOptimize; // Delete hacked module. 785 786 outs() << " Portion that is input to optimizer: "; 787 EmitProgressBitcode(ToOptimize, "tooptimize"); 788 delete ToOptimize; // Delete hacked module. 789 790 return; 791 } 792 793 /// CleanupAndPrepareModules - Get the specified modules ready for code 794 /// generator testing. 795 /// 796 static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test, 797 Module *Safe) { 798 // Clean up the modules, removing extra cruft that we don't need anymore... 799 Test = BD.performFinalCleanups(Test); 800 801 // If we are executing the JIT, we have several nasty issues to take care of. 802 if (!BD.isExecutingJIT()) return; 803 804 // First, if the main function is in the Safe module, we must add a stub to 805 // the Test module to call into it. Thus, we create a new function `main' 806 // which just calls the old one. 807 if (Function *oldMain = Safe->getFunction("main")) 808 if (!oldMain->isDeclaration()) { 809 // Rename it 810 oldMain->setName("llvm_bugpoint_old_main"); 811 // Create a NEW `main' function with same type in the test module. 812 Function *newMain = Function::Create(oldMain->getFunctionType(), 813 GlobalValue::ExternalLinkage, 814 "main", Test); 815 // Create an `oldmain' prototype in the test module, which will 816 // corresponds to the real main function in the same module. 817 Function *oldMainProto = Function::Create(oldMain->getFunctionType(), 818 GlobalValue::ExternalLinkage, 819 oldMain->getName(), Test); 820 // Set up and remember the argument list for the main function. 821 std::vector<Value*> args; 822 for (Function::arg_iterator 823 I = newMain->arg_begin(), E = newMain->arg_end(), 824 OI = oldMain->arg_begin(); I != E; ++I, ++OI) { 825 I->setName(OI->getName()); // Copy argument names from oldMain 826 args.push_back(I); 827 } 828 829 // Call the old main function and return its result 830 BasicBlock *BB = BasicBlock::Create(Safe->getContext(), "entry", newMain); 831 CallInst *call = CallInst::Create(oldMainProto, args, "", BB); 832 833 // If the type of old function wasn't void, return value of call 834 ReturnInst::Create(Safe->getContext(), call, BB); 835 } 836 837 // The second nasty issue we must deal with in the JIT is that the Safe 838 // module cannot directly reference any functions defined in the test 839 // module. Instead, we use a JIT API call to dynamically resolve the 840 // symbol. 841 842 // Add the resolver to the Safe module. 843 // Prototype: void *getPointerToNamedFunction(const char* Name) 844 Constant *resolverFunc = 845 Safe->getOrInsertFunction("getPointerToNamedFunction", 846 Type::getInt8PtrTy(Safe->getContext()), 847 Type::getInt8PtrTy(Safe->getContext()), 848 (Type *)nullptr); 849 850 // Use the function we just added to get addresses of functions we need. 851 for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) { 852 if (F->isDeclaration() && !F->use_empty() && &*F != resolverFunc && 853 !F->isIntrinsic() /* ignore intrinsics */) { 854 Function *TestFn = Test->getFunction(F->getName()); 855 856 // Don't forward functions which are external in the test module too. 857 if (TestFn && !TestFn->isDeclaration()) { 858 // 1. Add a string constant with its name to the global file 859 Constant *InitArray = 860 ConstantDataArray::getString(F->getContext(), F->getName()); 861 GlobalVariable *funcName = 862 new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/, 863 GlobalValue::InternalLinkage, InitArray, 864 F->getName() + "_name"); 865 866 // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an 867 // sbyte* so it matches the signature of the resolver function. 868 869 // GetElementPtr *funcName, ulong 0, ulong 0 870 std::vector<Constant*> GEPargs(2, 871 Constant::getNullValue(Type::getInt32Ty(F->getContext()))); 872 Value *GEP = ConstantExpr::getGetElementPtr(funcName, GEPargs); 873 std::vector<Value*> ResolverArgs; 874 ResolverArgs.push_back(GEP); 875 876 // Rewrite uses of F in global initializers, etc. to uses of a wrapper 877 // function that dynamically resolves the calls to F via our JIT API 878 if (!F->use_empty()) { 879 // Create a new global to hold the cached function pointer. 880 Constant *NullPtr = ConstantPointerNull::get(F->getType()); 881 GlobalVariable *Cache = 882 new GlobalVariable(*F->getParent(), F->getType(), 883 false, GlobalValue::InternalLinkage, 884 NullPtr,F->getName()+".fpcache"); 885 886 // Construct a new stub function that will re-route calls to F 887 FunctionType *FuncTy = F->getFunctionType(); 888 Function *FuncWrapper = Function::Create(FuncTy, 889 GlobalValue::InternalLinkage, 890 F->getName() + "_wrapper", 891 F->getParent()); 892 BasicBlock *EntryBB = BasicBlock::Create(F->getContext(), 893 "entry", FuncWrapper); 894 BasicBlock *DoCallBB = BasicBlock::Create(F->getContext(), 895 "usecache", FuncWrapper); 896 BasicBlock *LookupBB = BasicBlock::Create(F->getContext(), 897 "lookupfp", FuncWrapper); 898 899 // Check to see if we already looked up the value. 900 Value *CachedVal = new LoadInst(Cache, "fpcache", EntryBB); 901 Value *IsNull = new ICmpInst(*EntryBB, ICmpInst::ICMP_EQ, CachedVal, 902 NullPtr, "isNull"); 903 BranchInst::Create(LookupBB, DoCallBB, IsNull, EntryBB); 904 905 // Resolve the call to function F via the JIT API: 906 // 907 // call resolver(GetElementPtr...) 908 CallInst *Resolver = 909 CallInst::Create(resolverFunc, ResolverArgs, "resolver", LookupBB); 910 911 // Cast the result from the resolver to correctly-typed function. 912 CastInst *CastedResolver = 913 new BitCastInst(Resolver, 914 PointerType::getUnqual(F->getFunctionType()), 915 "resolverCast", LookupBB); 916 917 // Save the value in our cache. 918 new StoreInst(CastedResolver, Cache, LookupBB); 919 BranchInst::Create(DoCallBB, LookupBB); 920 921 PHINode *FuncPtr = PHINode::Create(NullPtr->getType(), 2, 922 "fp", DoCallBB); 923 FuncPtr->addIncoming(CastedResolver, LookupBB); 924 FuncPtr->addIncoming(CachedVal, EntryBB); 925 926 // Save the argument list. 927 std::vector<Value*> Args; 928 for (Function::arg_iterator i = FuncWrapper->arg_begin(), 929 e = FuncWrapper->arg_end(); i != e; ++i) 930 Args.push_back(i); 931 932 // Pass on the arguments to the real function, return its result 933 if (F->getReturnType()->isVoidTy()) { 934 CallInst::Create(FuncPtr, Args, "", DoCallBB); 935 ReturnInst::Create(F->getContext(), DoCallBB); 936 } else { 937 CallInst *Call = CallInst::Create(FuncPtr, Args, 938 "retval", DoCallBB); 939 ReturnInst::Create(F->getContext(),Call, DoCallBB); 940 } 941 942 // Use the wrapper function instead of the old function 943 F->replaceAllUsesWith(FuncWrapper); 944 } 945 } 946 } 947 } 948 949 if (verifyModule(*Test) || verifyModule(*Safe)) { 950 errs() << "Bugpoint has a bug, which corrupted a module!!\n"; 951 abort(); 952 } 953 } 954 955 956 957 /// TestCodeGenerator - This is the predicate function used to check to see if 958 /// the "Test" portion of the program is miscompiled by the code generator under 959 /// test. If so, return true. In any case, both module arguments are deleted. 960 /// 961 static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe, 962 std::string &Error) { 963 CleanupAndPrepareModules(BD, Test, Safe); 964 965 SmallString<128> TestModuleBC; 966 int TestModuleFD; 967 std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc", 968 TestModuleFD, TestModuleBC); 969 if (EC) { 970 errs() << BD.getToolName() << "Error making unique filename: " 971 << EC.message() << "\n"; 972 exit(1); 973 } 974 if (BD.writeProgramToFile(TestModuleBC.str(), TestModuleFD, Test)) { 975 errs() << "Error writing bitcode to `" << TestModuleBC.str() 976 << "'\nExiting."; 977 exit(1); 978 } 979 delete Test; 980 981 FileRemover TestModuleBCRemover(TestModuleBC.str(), !SaveTemps); 982 983 // Make the shared library 984 SmallString<128> SafeModuleBC; 985 int SafeModuleFD; 986 EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD, 987 SafeModuleBC); 988 if (EC) { 989 errs() << BD.getToolName() << "Error making unique filename: " 990 << EC.message() << "\n"; 991 exit(1); 992 } 993 994 if (BD.writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, Safe)) { 995 errs() << "Error writing bitcode to `" << SafeModuleBC.str() 996 << "'\nExiting."; 997 exit(1); 998 } 999 1000 FileRemover SafeModuleBCRemover(SafeModuleBC.str(), !SaveTemps); 1001 1002 std::string SharedObject = BD.compileSharedObject(SafeModuleBC.str(), Error); 1003 if (!Error.empty()) 1004 return false; 1005 delete Safe; 1006 1007 FileRemover SharedObjectRemover(SharedObject, !SaveTemps); 1008 1009 // Run the code generator on the `Test' code, loading the shared library. 1010 // The function returns whether or not the new output differs from reference. 1011 bool Result = BD.diffProgram(BD.getProgram(), TestModuleBC.str(), 1012 SharedObject, false, &Error); 1013 if (!Error.empty()) 1014 return false; 1015 1016 if (Result) 1017 errs() << ": still failing!\n"; 1018 else 1019 errs() << ": didn't fail.\n"; 1020 1021 return Result; 1022 } 1023 1024 1025 /// debugCodeGenerator - debug errors in LLC, LLI, or CBE. 1026 /// 1027 bool BugDriver::debugCodeGenerator(std::string *Error) { 1028 if ((void*)SafeInterpreter == (void*)Interpreter) { 1029 std::string Result = executeProgramSafely(Program, "bugpoint.safe.out", 1030 Error); 1031 if (Error->empty()) { 1032 outs() << "\n*** The \"safe\" i.e. 'known good' backend cannot match " 1033 << "the reference diff. This may be due to a\n front-end " 1034 << "bug or a bug in the original program, but this can also " 1035 << "happen if bugpoint isn't running the program with the " 1036 << "right flags or input.\n I left the result of executing " 1037 << "the program with the \"safe\" backend in this file for " 1038 << "you: '" 1039 << Result << "'.\n"; 1040 } 1041 return true; 1042 } 1043 1044 DisambiguateGlobalSymbols(Program); 1045 1046 std::vector<Function*> Funcs = DebugAMiscompilation(*this, TestCodeGenerator, 1047 *Error); 1048 if (!Error->empty()) 1049 return true; 1050 1051 // Split the module into the two halves of the program we want. 1052 ValueToValueMapTy VMap; 1053 Module *ToNotCodeGen = CloneModule(getProgram(), VMap); 1054 Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs, VMap); 1055 1056 // Condition the modules 1057 CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen); 1058 1059 SmallString<128> TestModuleBC; 1060 int TestModuleFD; 1061 std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc", 1062 TestModuleFD, TestModuleBC); 1063 if (EC) { 1064 errs() << getToolName() << "Error making unique filename: " 1065 << EC.message() << "\n"; 1066 exit(1); 1067 } 1068 1069 if (writeProgramToFile(TestModuleBC.str(), TestModuleFD, ToCodeGen)) { 1070 errs() << "Error writing bitcode to `" << TestModuleBC.str() 1071 << "'\nExiting."; 1072 exit(1); 1073 } 1074 delete ToCodeGen; 1075 1076 // Make the shared library 1077 SmallString<128> SafeModuleBC; 1078 int SafeModuleFD; 1079 EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD, 1080 SafeModuleBC); 1081 if (EC) { 1082 errs() << getToolName() << "Error making unique filename: " 1083 << EC.message() << "\n"; 1084 exit(1); 1085 } 1086 1087 if (writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, ToNotCodeGen)) { 1088 errs() << "Error writing bitcode to `" << SafeModuleBC.str() 1089 << "'\nExiting."; 1090 exit(1); 1091 } 1092 std::string SharedObject = compileSharedObject(SafeModuleBC.str(), *Error); 1093 if (!Error->empty()) 1094 return true; 1095 delete ToNotCodeGen; 1096 1097 outs() << "You can reproduce the problem with the command line: \n"; 1098 if (isExecutingJIT()) { 1099 outs() << " lli -load " << SharedObject << " " << TestModuleBC.str(); 1100 } else { 1101 outs() << " llc " << TestModuleBC.str() << " -o " << TestModuleBC.str() 1102 << ".s\n"; 1103 outs() << " gcc " << SharedObject << " " << TestModuleBC.str() 1104 << ".s -o " << TestModuleBC.str() << ".exe"; 1105 #if defined (HAVE_LINK_R) 1106 outs() << " -Wl,-R."; 1107 #endif 1108 outs() << "\n"; 1109 outs() << " " << TestModuleBC.str() << ".exe"; 1110 } 1111 for (unsigned i = 0, e = InputArgv.size(); i != e; ++i) 1112 outs() << " " << InputArgv[i]; 1113 outs() << '\n'; 1114 outs() << "The shared object was created with:\n llc -march=c " 1115 << SafeModuleBC.str() << " -o temporary.c\n" 1116 << " gcc -xc temporary.c -O2 -o " << SharedObject; 1117 if (TargetTriple.getArch() == Triple::sparc) 1118 outs() << " -G"; // Compile a shared library, `-G' for Sparc 1119 else 1120 outs() << " -fPIC -shared"; // `-shared' for Linux/X86, maybe others 1121 1122 outs() << " -fno-strict-aliasing\n"; 1123 1124 return false; 1125 } 1126