1 //===- Miscompilation.cpp - Debug program miscompilations -----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements optimizer and code generation miscompilation debugging
13 //===----------------------------------------------------------------------===//
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/DiagnosticPrinter.h"
22 #include "llvm/IR/Instructions.h"
23 #include "llvm/IR/Module.h"
24 #include "llvm/IR/Verifier.h"
25 #include "llvm/Linker/Linker.h"
26 #include "llvm/Pass.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/FileUtilities.h"
29 #include "llvm/Transforms/Utils/Cloning.h"
33 extern cl::opt<std::string> OutputPrefix;
34 extern cl::list<std::string> InputArgv;
38 static llvm::cl::opt<bool>
39 DisableLoopExtraction("disable-loop-extraction",
40 cl::desc("Don't extract loops when searching for miscompilations"),
42 static llvm::cl::opt<bool>
43 DisableBlockExtraction("disable-block-extraction",
44 cl::desc("Don't extract blocks when searching for miscompilations"),
47 class ReduceMiscompilingPasses : public ListReducer<std::string> {
50 ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
52 TestResult doTest(std::vector<std::string> &Prefix,
53 std::vector<std::string> &Suffix,
54 std::string &Error) override;
58 /// TestResult - After passes have been split into a test group and a control
59 /// group, see if they still break the program.
61 ReduceMiscompilingPasses::TestResult
62 ReduceMiscompilingPasses::doTest(std::vector<std::string> &Prefix,
63 std::vector<std::string> &Suffix,
65 // First, run the program with just the Suffix passes. If it is still broken
66 // with JUST the kept passes, discard the prefix passes.
67 outs() << "Checking to see if '" << getPassesString(Suffix)
68 << "' compiles correctly: ";
70 std::string BitcodeResult;
71 if (BD.runPasses(BD.getProgram(), Suffix, BitcodeResult, false/*delete*/,
73 errs() << " Error running this sequence of passes"
74 << " on the input program!\n";
75 BD.setPassesToRun(Suffix);
76 BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false);
77 exit(BD.debugOptimizerCrash());
80 // Check to see if the finished program matches the reference output...
81 bool Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "",
82 true /*delete bitcode*/, &Error);
88 errs() << BD.getToolName() << ": I'm confused: the test fails when "
89 << "no passes are run, nondeterministic program?\n";
92 return KeepSuffix; // Miscompilation detected!
94 outs() << " yup.\n"; // No miscompilation!
96 if (Prefix.empty()) return NoFailure;
98 // Next, see if the program is broken if we run the "prefix" passes first,
99 // then separately run the "kept" passes.
100 outs() << "Checking to see if '" << getPassesString(Prefix)
101 << "' compiles correctly: ";
103 // If it is not broken with the kept passes, it's possible that the prefix
104 // passes must be run before the kept passes to break it. If the program
105 // WORKS after the prefix passes, but then fails if running the prefix AND
106 // kept passes, we can update our bitcode file to include the result of the
107 // prefix passes, then discard the prefix passes.
109 if (BD.runPasses(BD.getProgram(), Prefix, BitcodeResult, false/*delete*/,
111 errs() << " Error running this sequence of passes"
112 << " on the input program!\n";
113 BD.setPassesToRun(Prefix);
114 BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false);
115 exit(BD.debugOptimizerCrash());
118 // If the prefix maintains the predicate by itself, only keep the prefix!
119 Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", false, &Error);
121 return InternalError;
123 outs() << " nope.\n";
124 sys::fs::remove(BitcodeResult);
127 outs() << " yup.\n"; // No miscompilation!
129 // Ok, so now we know that the prefix passes work, try running the suffix
130 // passes on the result of the prefix passes.
132 std::unique_ptr<Module> PrefixOutput =
133 parseInputFile(BitcodeResult, BD.getContext());
135 errs() << BD.getToolName() << ": Error reading bitcode file '"
136 << BitcodeResult << "'!\n";
139 sys::fs::remove(BitcodeResult);
141 // Don't check if there are no passes in the suffix.
145 outs() << "Checking to see if '" << getPassesString(Suffix)
146 << "' passes compile correctly after the '"
147 << getPassesString(Prefix) << "' passes: ";
149 std::unique_ptr<Module> OriginalInput(
150 BD.swapProgramIn(PrefixOutput.release()));
151 if (BD.runPasses(BD.getProgram(), Suffix, BitcodeResult, false/*delete*/,
153 errs() << " Error running this sequence of passes"
154 << " on the input program!\n";
155 BD.setPassesToRun(Suffix);
156 BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false);
157 exit(BD.debugOptimizerCrash());
161 Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "",
162 true /*delete bitcode*/, &Error);
164 return InternalError;
166 outs() << " nope.\n";
170 // Otherwise, we must not be running the bad pass anymore.
171 outs() << " yup.\n"; // No miscompilation!
172 // Restore orig program & free test.
173 delete BD.swapProgramIn(OriginalInput.release());
178 class ReduceMiscompilingFunctions : public ListReducer<Function*> {
180 bool (*TestFn)(BugDriver &, Module *, Module *, std::string &);
182 ReduceMiscompilingFunctions(BugDriver &bd,
183 bool (*F)(BugDriver &, Module *, Module *,
185 : BD(bd), TestFn(F) {}
187 TestResult doTest(std::vector<Function*> &Prefix,
188 std::vector<Function*> &Suffix,
189 std::string &Error) override {
190 if (!Suffix.empty()) {
191 bool Ret = TestFuncs(Suffix, Error);
193 return InternalError;
197 if (!Prefix.empty()) {
198 bool Ret = TestFuncs(Prefix, Error);
200 return InternalError;
207 bool TestFuncs(const std::vector<Function*> &Prefix, std::string &Error);
211 static void diagnosticHandler(const DiagnosticInfo &DI) {
212 DiagnosticPrinterRawOStream DP(errs());
215 if (DI.getSeverity() == DS_Error)
219 /// TestMergedProgram - Given two modules, link them together and run the
220 /// program, checking to see if the program matches the diff. If there is
221 /// an error, return NULL. If not, return the merged module. The Broken argument
222 /// will be set to true if the output is different. If the DeleteInputs
223 /// argument is set to true then this function deletes both input
224 /// modules before it returns.
226 static Module *TestMergedProgram(const BugDriver &BD, Module *M1, Module *M2,
227 bool DeleteInputs, std::string &Error,
229 // Link the two portions of the program back to together.
231 M1 = CloneModule(M1).release();
232 M2 = CloneModule(M2).release();
234 if (Linker::linkModules(*M1, *M2, diagnosticHandler))
236 delete M2; // We are done with this module.
238 // Execute the program.
239 Broken = BD.diffProgram(M1, "", "", false, &Error);
240 if (!Error.empty()) {
241 // Delete the linked module
248 /// TestFuncs - split functions in a Module into two groups: those that are
249 /// under consideration for miscompilation vs. those that are not, and test
250 /// accordingly. Each group of functions becomes a separate Module.
252 bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs,
253 std::string &Error) {
254 // Test to see if the function is misoptimized if we ONLY run it on the
255 // functions listed in Funcs.
256 outs() << "Checking to see if the program is misoptimized when "
257 << (Funcs.size()==1 ? "this function is" : "these functions are")
258 << " run through the pass"
259 << (BD.getPassesToRun().size() == 1 ? "" : "es") << ":";
260 PrintFunctionList(Funcs);
263 // Create a clone for two reasons:
264 // * If the optimization passes delete any function, the deleted function
265 // will be in the clone and Funcs will still point to valid memory
266 // * If the optimization passes use interprocedural information to break
267 // a function, we want to continue with the original function. Otherwise
268 // we can conclude that a function triggers the bug when in fact one
269 // needs a larger set of original functions to do so.
270 ValueToValueMapTy VMap;
271 Module *Clone = CloneModule(BD.getProgram(), VMap).release();
272 Module *Orig = BD.swapProgramIn(Clone);
274 std::vector<Function*> FuncsOnClone;
275 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
276 Function *F = cast<Function>(VMap[Funcs[i]]);
277 FuncsOnClone.push_back(F);
280 // Split the module into the two halves of the program we want.
282 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap).release();
283 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, FuncsOnClone,
286 // Run the predicate, note that the predicate will delete both input modules.
287 bool Broken = TestFn(BD, ToOptimize, ToNotOptimize, Error);
289 delete BD.swapProgramIn(Orig);
294 /// DisambiguateGlobalSymbols - Give anonymous global values names.
296 static void DisambiguateGlobalSymbols(Module *M) {
297 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
300 I->setName("anon_global");
301 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
303 I->setName("anon_fn");
306 /// ExtractLoops - Given a reduced list of functions that still exposed the bug,
307 /// check to see if we can extract the loops in the region without obscuring the
308 /// bug. If so, it reduces the amount of code identified.
310 static bool ExtractLoops(BugDriver &BD,
311 bool (*TestFn)(BugDriver &, Module *, Module *,
313 std::vector<Function*> &MiscompiledFunctions,
314 std::string &Error) {
315 bool MadeChange = false;
317 if (BugpointIsInterrupted) return MadeChange;
319 ValueToValueMapTy VMap;
320 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap).release();
321 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
322 MiscompiledFunctions,
324 Module *ToOptimizeLoopExtracted = BD.extractLoop(ToOptimize).release();
325 if (!ToOptimizeLoopExtracted) {
326 // If the loop extractor crashed or if there were no extractible loops,
327 // then this chapter of our odyssey is over with.
328 delete ToNotOptimize;
333 errs() << "Extracted a loop from the breaking portion of the program.\n";
335 // Bugpoint is intentionally not very trusting of LLVM transformations. In
336 // particular, we're not going to assume that the loop extractor works, so
337 // we're going to test the newly loop extracted program to make sure nothing
338 // has broken. If something broke, then we'll inform the user and stop
340 AbstractInterpreter *AI = BD.switchToSafeInterpreter();
342 Module *New = TestMergedProgram(BD, ToOptimizeLoopExtracted,
343 ToNotOptimize, false, Error, Failure);
347 // Delete the original and set the new program.
348 Module *Old = BD.swapProgramIn(New);
349 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
350 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
354 BD.switchToInterpreter(AI);
356 // Merged program doesn't work anymore!
357 errs() << " *** ERROR: Loop extraction broke the program. :("
358 << " Please report a bug!\n";
359 errs() << " Continuing on with un-loop-extracted version.\n";
361 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-tno.bc",
363 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to.bc",
365 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to-le.bc",
366 ToOptimizeLoopExtracted);
368 errs() << "Please submit the "
369 << OutputPrefix << "-loop-extract-fail-*.bc files.\n";
371 delete ToNotOptimize;
375 BD.switchToInterpreter(AI);
377 outs() << " Testing after loop extraction:\n";
378 // Clone modules, the tester function will free them.
379 Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted, VMap).release();
380 Module *TNOBackup = CloneModule(ToNotOptimize, VMap).release();
382 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
383 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
385 Failure = TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize, Error);
389 ToOptimizeLoopExtracted = TOLEBackup;
390 ToNotOptimize = TNOBackup;
393 outs() << "*** Loop extraction masked the problem. Undoing.\n";
394 // If the program is not still broken, then loop extraction did something
395 // that masked the error. Stop loop extraction now.
397 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
398 for (Function *F : MiscompiledFunctions) {
399 MisCompFunctions.emplace_back(F->getName(), F->getFunctionType());
402 if (Linker::linkModules(*ToNotOptimize, *ToOptimizeLoopExtracted,
406 MiscompiledFunctions.clear();
407 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
408 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
410 assert(NewF && "Function not found??");
411 MiscompiledFunctions.push_back(NewF);
414 delete ToOptimizeLoopExtracted;
415 BD.setNewProgram(ToNotOptimize);
419 outs() << "*** Loop extraction successful!\n";
421 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
422 for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
423 E = ToOptimizeLoopExtracted->end(); I != E; ++I)
424 if (!I->isDeclaration())
425 MisCompFunctions.emplace_back(I->getName(), I->getFunctionType());
427 // Okay, great! Now we know that we extracted a loop and that loop
428 // extraction both didn't break the program, and didn't mask the problem.
429 // Replace the current program with the loop extracted version, and try to
430 // extract another loop.
431 if (Linker::linkModules(*ToNotOptimize, *ToOptimizeLoopExtracted,
435 delete ToOptimizeLoopExtracted;
437 // All of the Function*'s in the MiscompiledFunctions list are in the old
438 // module. Update this list to include all of the functions in the
439 // optimized and loop extracted module.
440 MiscompiledFunctions.clear();
441 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
442 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
444 assert(NewF && "Function not found??");
445 MiscompiledFunctions.push_back(NewF);
448 BD.setNewProgram(ToNotOptimize);
454 class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> {
456 bool (*TestFn)(BugDriver &, Module *, Module *, std::string &);
457 std::vector<Function*> FunctionsBeingTested;
459 ReduceMiscompiledBlocks(BugDriver &bd,
460 bool (*F)(BugDriver &, Module *, Module *,
462 const std::vector<Function*> &Fns)
463 : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {}
465 TestResult doTest(std::vector<BasicBlock*> &Prefix,
466 std::vector<BasicBlock*> &Suffix,
467 std::string &Error) override {
468 if (!Suffix.empty()) {
469 bool Ret = TestFuncs(Suffix, Error);
471 return InternalError;
475 if (!Prefix.empty()) {
476 bool Ret = TestFuncs(Prefix, Error);
478 return InternalError;
485 bool TestFuncs(const std::vector<BasicBlock*> &BBs, std::string &Error);
489 /// TestFuncs - Extract all blocks for the miscompiled functions except for the
490 /// specified blocks. If the problem still exists, return true.
492 bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs,
493 std::string &Error) {
494 // Test to see if the function is misoptimized if we ONLY run it on the
495 // functions listed in Funcs.
496 outs() << "Checking to see if the program is misoptimized when all ";
498 outs() << "but these " << BBs.size() << " blocks are extracted: ";
499 for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i)
500 outs() << BBs[i]->getName() << " ";
501 if (BBs.size() > 10) outs() << "...";
503 outs() << "blocks are extracted.";
507 // Split the module into the two halves of the program we want.
508 ValueToValueMapTy VMap;
509 Module *Clone = CloneModule(BD.getProgram(), VMap).release();
510 Module *Orig = BD.swapProgramIn(Clone);
511 std::vector<Function*> FuncsOnClone;
512 std::vector<BasicBlock*> BBsOnClone;
513 for (unsigned i = 0, e = FunctionsBeingTested.size(); i != e; ++i) {
514 Function *F = cast<Function>(VMap[FunctionsBeingTested[i]]);
515 FuncsOnClone.push_back(F);
517 for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
518 BasicBlock *BB = cast<BasicBlock>(VMap[BBs[i]]);
519 BBsOnClone.push_back(BB);
523 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap).release();
524 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
528 // Try the extraction. If it doesn't work, then the block extractor crashed
529 // or something, in which case bugpoint can't chase down this possibility.
530 if (std::unique_ptr<Module> New =
531 BD.extractMappedBlocksFromModule(BBsOnClone, ToOptimize)) {
533 // Run the predicate,
534 // note that the predicate will delete both input modules.
535 bool Ret = TestFn(BD, New.get(), ToNotOptimize, Error);
536 delete BD.swapProgramIn(Orig);
539 delete BD.swapProgramIn(Orig);
541 delete ToNotOptimize;
546 /// ExtractBlocks - Given a reduced list of functions that still expose the bug,
547 /// extract as many basic blocks from the region as possible without obscuring
550 static bool ExtractBlocks(BugDriver &BD,
551 bool (*TestFn)(BugDriver &, Module *, Module *,
553 std::vector<Function*> &MiscompiledFunctions,
554 std::string &Error) {
555 if (BugpointIsInterrupted) return false;
557 std::vector<BasicBlock*> Blocks;
558 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
559 for (BasicBlock &BB : *MiscompiledFunctions[i])
560 Blocks.push_back(&BB);
562 // Use the list reducer to identify blocks that can be extracted without
563 // obscuring the bug. The Blocks list will end up containing blocks that must
564 // be retained from the original program.
565 unsigned OldSize = Blocks.size();
567 // Check to see if all blocks are extractible first.
568 bool Ret = ReduceMiscompiledBlocks(BD, TestFn, MiscompiledFunctions)
569 .TestFuncs(std::vector<BasicBlock*>(), Error);
575 ReduceMiscompiledBlocks(BD, TestFn,
576 MiscompiledFunctions).reduceList(Blocks, Error);
579 if (Blocks.size() == OldSize)
583 ValueToValueMapTy VMap;
584 Module *ProgClone = CloneModule(BD.getProgram(), VMap).release();
585 Module *ToExtract = SplitFunctionsOutOfModule(ProgClone,
586 MiscompiledFunctions,
588 std::unique_ptr<Module> Extracted =
589 BD.extractMappedBlocksFromModule(Blocks, ToExtract);
591 // Weird, extraction should have worked.
592 errs() << "Nondeterministic problem extracting blocks??\n";
598 // Otherwise, block extraction succeeded. Link the two program fragments back
602 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
603 for (Module::iterator I = Extracted->begin(), E = Extracted->end();
605 if (!I->isDeclaration())
606 MisCompFunctions.emplace_back(I->getName(), I->getFunctionType());
608 if (Linker::linkModules(*ProgClone, *Extracted, diagnosticHandler))
611 // Set the new program and delete the old one.
612 BD.setNewProgram(ProgClone);
614 // Update the list of miscompiled functions.
615 MiscompiledFunctions.clear();
617 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
618 Function *NewF = ProgClone->getFunction(MisCompFunctions[i].first);
619 assert(NewF && "Function not found??");
620 MiscompiledFunctions.push_back(NewF);
627 /// DebugAMiscompilation - This is a generic driver to narrow down
628 /// miscompilations, either in an optimization or a code generator.
630 static std::vector<Function*>
631 DebugAMiscompilation(BugDriver &BD,
632 bool (*TestFn)(BugDriver &, Module *, Module *,
634 std::string &Error) {
635 // Okay, now that we have reduced the list of passes which are causing the
636 // failure, see if we can pin down which functions are being
637 // miscompiled... first build a list of all of the non-external functions in
639 std::vector<Function*> MiscompiledFunctions;
640 Module *Prog = BD.getProgram();
641 for (Function &F : *Prog)
642 if (!F.isDeclaration())
643 MiscompiledFunctions.push_back(&F);
645 // Do the reduction...
646 if (!BugpointIsInterrupted)
647 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
649 if (!Error.empty()) {
650 errs() << "\n***Cannot reduce functions: ";
651 return MiscompiledFunctions;
653 outs() << "\n*** The following function"
654 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
655 << " being miscompiled: ";
656 PrintFunctionList(MiscompiledFunctions);
659 // See if we can rip any loops out of the miscompiled functions and still
660 // trigger the problem.
662 if (!BugpointIsInterrupted && !DisableLoopExtraction) {
663 bool Ret = ExtractLoops(BD, TestFn, MiscompiledFunctions, Error);
665 return MiscompiledFunctions;
667 // Okay, we extracted some loops and the problem still appears. See if
668 // we can eliminate some of the created functions from being candidates.
669 DisambiguateGlobalSymbols(BD.getProgram());
671 // Do the reduction...
672 if (!BugpointIsInterrupted)
673 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
676 return MiscompiledFunctions;
678 outs() << "\n*** The following function"
679 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
680 << " being miscompiled: ";
681 PrintFunctionList(MiscompiledFunctions);
686 if (!BugpointIsInterrupted && !DisableBlockExtraction) {
687 bool Ret = ExtractBlocks(BD, TestFn, MiscompiledFunctions, Error);
689 return MiscompiledFunctions;
691 // Okay, we extracted some blocks and the problem still appears. See if
692 // we can eliminate some of the created functions from being candidates.
693 DisambiguateGlobalSymbols(BD.getProgram());
695 // Do the reduction...
696 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
699 return MiscompiledFunctions;
701 outs() << "\n*** The following function"
702 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
703 << " being miscompiled: ";
704 PrintFunctionList(MiscompiledFunctions);
709 return MiscompiledFunctions;
712 /// TestOptimizer - This is the predicate function used to check to see if the
713 /// "Test" portion of the program is misoptimized. If so, return true. In any
714 /// case, both module arguments are deleted.
716 static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe,
717 std::string &Error) {
718 // Run the optimization passes on ToOptimize, producing a transformed version
719 // of the functions being tested.
720 outs() << " Optimizing functions being tested: ";
721 std::unique_ptr<Module> Optimized = BD.runPassesOn(Test, BD.getPassesToRun(),
722 /*AutoDebugCrashes*/ true);
726 outs() << " Checking to see if the merged program executes correctly: ";
729 TestMergedProgram(BD, Optimized.get(), Safe, true, Error, Broken);
731 outs() << (Broken ? " nope.\n" : " yup.\n");
732 // Delete the original and set the new program.
733 delete BD.swapProgramIn(New);
739 /// debugMiscompilation - This method is used when the passes selected are not
740 /// crashing, but the generated output is semantically different from the
743 void BugDriver::debugMiscompilation(std::string *Error) {
744 // Make sure something was miscompiled...
745 if (!BugpointIsInterrupted)
746 if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun, *Error)) {
748 errs() << "*** Optimized program matches reference output! No problem"
749 << " detected...\nbugpoint can't help you with your problem!\n";
753 outs() << "\n*** Found miscompiling pass"
754 << (getPassesToRun().size() == 1 ? "" : "es") << ": "
755 << getPassesString(getPassesToRun()) << '\n';
756 EmitProgressBitcode(Program, "passinput");
758 std::vector<Function *> MiscompiledFunctions =
759 DebugAMiscompilation(*this, TestOptimizer, *Error);
763 // Output a bunch of bitcode files for the user...
764 outs() << "Outputting reduced bitcode files which expose the problem:\n";
765 ValueToValueMapTy VMap;
766 Module *ToNotOptimize = CloneModule(getProgram(), VMap).release();
767 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
768 MiscompiledFunctions,
771 outs() << " Non-optimized portion: ";
772 EmitProgressBitcode(ToNotOptimize, "tonotoptimize", true);
773 delete ToNotOptimize; // Delete hacked module.
775 outs() << " Portion that is input to optimizer: ";
776 EmitProgressBitcode(ToOptimize, "tooptimize");
777 delete ToOptimize; // Delete hacked module.
782 /// CleanupAndPrepareModules - Get the specified modules ready for code
783 /// generator testing.
785 static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
787 // Clean up the modules, removing extra cruft that we don't need anymore...
788 Test = BD.performFinalCleanups(Test).release();
790 // If we are executing the JIT, we have several nasty issues to take care of.
791 if (!BD.isExecutingJIT()) return;
793 // First, if the main function is in the Safe module, we must add a stub to
794 // the Test module to call into it. Thus, we create a new function `main'
795 // which just calls the old one.
796 if (Function *oldMain = Safe->getFunction("main"))
797 if (!oldMain->isDeclaration()) {
799 oldMain->setName("llvm_bugpoint_old_main");
800 // Create a NEW `main' function with same type in the test module.
801 Function *newMain = Function::Create(oldMain->getFunctionType(),
802 GlobalValue::ExternalLinkage,
804 // Create an `oldmain' prototype in the test module, which will
805 // corresponds to the real main function in the same module.
806 Function *oldMainProto = Function::Create(oldMain->getFunctionType(),
807 GlobalValue::ExternalLinkage,
808 oldMain->getName(), Test);
809 // Set up and remember the argument list for the main function.
810 std::vector<Value*> args;
811 for (Function::arg_iterator
812 I = newMain->arg_begin(), E = newMain->arg_end(),
813 OI = oldMain->arg_begin(); I != E; ++I, ++OI) {
814 I->setName(OI->getName()); // Copy argument names from oldMain
818 // Call the old main function and return its result
819 BasicBlock *BB = BasicBlock::Create(Safe->getContext(), "entry", newMain);
820 CallInst *call = CallInst::Create(oldMainProto, args, "", BB);
822 // If the type of old function wasn't void, return value of call
823 ReturnInst::Create(Safe->getContext(), call, BB);
826 // The second nasty issue we must deal with in the JIT is that the Safe
827 // module cannot directly reference any functions defined in the test
828 // module. Instead, we use a JIT API call to dynamically resolve the
831 // Add the resolver to the Safe module.
832 // Prototype: void *getPointerToNamedFunction(const char* Name)
833 Constant *resolverFunc =
834 Safe->getOrInsertFunction("getPointerToNamedFunction",
835 Type::getInt8PtrTy(Safe->getContext()),
836 Type::getInt8PtrTy(Safe->getContext()),
839 // Use the function we just added to get addresses of functions we need.
840 for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) {
841 if (F->isDeclaration() && !F->use_empty() && &*F != resolverFunc &&
842 !F->isIntrinsic() /* ignore intrinsics */) {
843 Function *TestFn = Test->getFunction(F->getName());
845 // Don't forward functions which are external in the test module too.
846 if (TestFn && !TestFn->isDeclaration()) {
847 // 1. Add a string constant with its name to the global file
848 Constant *InitArray =
849 ConstantDataArray::getString(F->getContext(), F->getName());
850 GlobalVariable *funcName =
851 new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/,
852 GlobalValue::InternalLinkage, InitArray,
853 F->getName() + "_name");
855 // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
856 // sbyte* so it matches the signature of the resolver function.
858 // GetElementPtr *funcName, ulong 0, ulong 0
859 std::vector<Constant*> GEPargs(2,
860 Constant::getNullValue(Type::getInt32Ty(F->getContext())));
861 Value *GEP = ConstantExpr::getGetElementPtr(InitArray->getType(),
863 std::vector<Value*> ResolverArgs;
864 ResolverArgs.push_back(GEP);
866 // Rewrite uses of F in global initializers, etc. to uses of a wrapper
867 // function that dynamically resolves the calls to F via our JIT API
868 if (!F->use_empty()) {
869 // Create a new global to hold the cached function pointer.
870 Constant *NullPtr = ConstantPointerNull::get(F->getType());
871 GlobalVariable *Cache =
872 new GlobalVariable(*F->getParent(), F->getType(),
873 false, GlobalValue::InternalLinkage,
874 NullPtr,F->getName()+".fpcache");
876 // Construct a new stub function that will re-route calls to F
877 FunctionType *FuncTy = F->getFunctionType();
878 Function *FuncWrapper = Function::Create(FuncTy,
879 GlobalValue::InternalLinkage,
880 F->getName() + "_wrapper",
882 BasicBlock *EntryBB = BasicBlock::Create(F->getContext(),
883 "entry", FuncWrapper);
884 BasicBlock *DoCallBB = BasicBlock::Create(F->getContext(),
885 "usecache", FuncWrapper);
886 BasicBlock *LookupBB = BasicBlock::Create(F->getContext(),
887 "lookupfp", FuncWrapper);
889 // Check to see if we already looked up the value.
890 Value *CachedVal = new LoadInst(Cache, "fpcache", EntryBB);
891 Value *IsNull = new ICmpInst(*EntryBB, ICmpInst::ICMP_EQ, CachedVal,
893 BranchInst::Create(LookupBB, DoCallBB, IsNull, EntryBB);
895 // Resolve the call to function F via the JIT API:
897 // call resolver(GetElementPtr...)
899 CallInst::Create(resolverFunc, ResolverArgs, "resolver", LookupBB);
901 // Cast the result from the resolver to correctly-typed function.
902 CastInst *CastedResolver =
903 new BitCastInst(Resolver,
904 PointerType::getUnqual(F->getFunctionType()),
905 "resolverCast", LookupBB);
907 // Save the value in our cache.
908 new StoreInst(CastedResolver, Cache, LookupBB);
909 BranchInst::Create(DoCallBB, LookupBB);
911 PHINode *FuncPtr = PHINode::Create(NullPtr->getType(), 2,
913 FuncPtr->addIncoming(CastedResolver, LookupBB);
914 FuncPtr->addIncoming(CachedVal, EntryBB);
916 // Save the argument list.
917 std::vector<Value*> Args;
918 for (Argument &A : FuncWrapper->args())
921 // Pass on the arguments to the real function, return its result
922 if (F->getReturnType()->isVoidTy()) {
923 CallInst::Create(FuncPtr, Args, "", DoCallBB);
924 ReturnInst::Create(F->getContext(), DoCallBB);
926 CallInst *Call = CallInst::Create(FuncPtr, Args,
928 ReturnInst::Create(F->getContext(),Call, DoCallBB);
931 // Use the wrapper function instead of the old function
932 F->replaceAllUsesWith(FuncWrapper);
938 if (verifyModule(*Test) || verifyModule(*Safe)) {
939 errs() << "Bugpoint has a bug, which corrupted a module!!\n";
946 /// TestCodeGenerator - This is the predicate function used to check to see if
947 /// the "Test" portion of the program is miscompiled by the code generator under
948 /// test. If so, return true. In any case, both module arguments are deleted.
950 static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe,
951 std::string &Error) {
952 CleanupAndPrepareModules(BD, Test, Safe);
954 SmallString<128> TestModuleBC;
956 std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
957 TestModuleFD, TestModuleBC);
959 errs() << BD.getToolName() << "Error making unique filename: "
960 << EC.message() << "\n";
963 if (BD.writeProgramToFile(TestModuleBC.str(), TestModuleFD, Test)) {
964 errs() << "Error writing bitcode to `" << TestModuleBC.str()
970 FileRemover TestModuleBCRemover(TestModuleBC.str(), !SaveTemps);
972 // Make the shared library
973 SmallString<128> SafeModuleBC;
975 EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD,
978 errs() << BD.getToolName() << "Error making unique filename: "
979 << EC.message() << "\n";
983 if (BD.writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, Safe)) {
984 errs() << "Error writing bitcode to `" << SafeModuleBC
989 FileRemover SafeModuleBCRemover(SafeModuleBC.str(), !SaveTemps);
991 std::string SharedObject = BD.compileSharedObject(SafeModuleBC.str(), Error);
996 FileRemover SharedObjectRemover(SharedObject, !SaveTemps);
998 // Run the code generator on the `Test' code, loading the shared library.
999 // The function returns whether or not the new output differs from reference.
1000 bool Result = BD.diffProgram(BD.getProgram(), TestModuleBC.str(),
1001 SharedObject, false, &Error);
1006 errs() << ": still failing!\n";
1008 errs() << ": didn't fail.\n";
1014 /// debugCodeGenerator - debug errors in LLC, LLI, or CBE.
1016 bool BugDriver::debugCodeGenerator(std::string *Error) {
1017 if ((void*)SafeInterpreter == (void*)Interpreter) {
1018 std::string Result = executeProgramSafely(Program, "bugpoint.safe.out",
1020 if (Error->empty()) {
1021 outs() << "\n*** The \"safe\" i.e. 'known good' backend cannot match "
1022 << "the reference diff. This may be due to a\n front-end "
1023 << "bug or a bug in the original program, but this can also "
1024 << "happen if bugpoint isn't running the program with the "
1025 << "right flags or input.\n I left the result of executing "
1026 << "the program with the \"safe\" backend in this file for "
1028 << Result << "'.\n";
1033 DisambiguateGlobalSymbols(Program);
1035 std::vector<Function*> Funcs = DebugAMiscompilation(*this, TestCodeGenerator,
1037 if (!Error->empty())
1040 // Split the module into the two halves of the program we want.
1041 ValueToValueMapTy VMap;
1042 Module *ToNotCodeGen = CloneModule(getProgram(), VMap).release();
1043 Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs, VMap);
1045 // Condition the modules
1046 CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen);
1048 SmallString<128> TestModuleBC;
1050 std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
1051 TestModuleFD, TestModuleBC);
1053 errs() << getToolName() << "Error making unique filename: "
1054 << EC.message() << "\n";
1058 if (writeProgramToFile(TestModuleBC.str(), TestModuleFD, ToCodeGen)) {
1059 errs() << "Error writing bitcode to `" << TestModuleBC
1065 // Make the shared library
1066 SmallString<128> SafeModuleBC;
1068 EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD,
1071 errs() << getToolName() << "Error making unique filename: "
1072 << EC.message() << "\n";
1076 if (writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, ToNotCodeGen)) {
1077 errs() << "Error writing bitcode to `" << SafeModuleBC
1081 std::string SharedObject = compileSharedObject(SafeModuleBC.str(), *Error);
1082 if (!Error->empty())
1084 delete ToNotCodeGen;
1086 outs() << "You can reproduce the problem with the command line: \n";
1087 if (isExecutingJIT()) {
1088 outs() << " lli -load " << SharedObject << " " << TestModuleBC;
1090 outs() << " llc " << TestModuleBC << " -o " << TestModuleBC
1092 outs() << " cc " << SharedObject << " " << TestModuleBC.str()
1093 << ".s -o " << TestModuleBC << ".exe";
1094 #if defined (HAVE_LINK_R)
1095 outs() << " -Wl,-R.";
1098 outs() << " " << TestModuleBC << ".exe";
1100 for (unsigned i = 0, e = InputArgv.size(); i != e; ++i)
1101 outs() << " " << InputArgv[i];
1103 outs() << "The shared object was created with:\n llc -march=c "
1104 << SafeModuleBC.str() << " -o temporary.c\n"
1105 << " cc -xc temporary.c -O2 -o " << SharedObject;
1106 if (TargetTriple.getArch() == Triple::sparc)
1107 outs() << " -G"; // Compile a shared library, `-G' for Sparc
1109 outs() << " -fPIC -shared"; // `-shared' for Linux/X86, maybe others
1111 outs() << " -fno-strict-aliasing\n";