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/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"
32 extern cl::opt<std::string> OutputPrefix;
33 extern cl::list<std::string> InputArgv;
37 static llvm::cl::opt<bool>
38 DisableLoopExtraction("disable-loop-extraction",
39 cl::desc("Don't extract loops when searching for miscompilations"),
41 static llvm::cl::opt<bool>
42 DisableBlockExtraction("disable-block-extraction",
43 cl::desc("Don't extract blocks when searching for miscompilations"),
46 class ReduceMiscompilingPasses : public ListReducer<std::string> {
49 ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
51 TestResult doTest(std::vector<std::string> &Prefix,
52 std::vector<std::string> &Suffix,
53 std::string &Error) override;
57 /// TestResult - After passes have been split into a test group and a control
58 /// group, see if they still break the program.
60 ReduceMiscompilingPasses::TestResult
61 ReduceMiscompilingPasses::doTest(std::vector<std::string> &Prefix,
62 std::vector<std::string> &Suffix,
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: ";
69 std::string BitcodeResult;
70 if (BD.runPasses(BD.getProgram(), Suffix, BitcodeResult, false/*delete*/,
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());
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);
87 errs() << BD.getToolName() << ": I'm confused: the test fails when "
88 << "no passes are run, nondeterministic program?\n";
91 return KeepSuffix; // Miscompilation detected!
93 outs() << " yup.\n"; // No miscompilation!
95 if (Prefix.empty()) return NoFailure;
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: ";
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.
108 if (BD.runPasses(BD.getProgram(), Prefix, BitcodeResult, false/*delete*/,
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());
117 // If the prefix maintains the predicate by itself, only keep the prefix!
118 Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", false, &Error);
120 return InternalError;
122 outs() << " nope.\n";
123 sys::fs::remove(BitcodeResult);
126 outs() << " yup.\n"; // No miscompilation!
128 // Ok, so now we know that the prefix passes work, try running the suffix
129 // passes on the result of the prefix passes.
131 std::unique_ptr<Module> PrefixOutput =
132 parseInputFile(BitcodeResult, BD.getContext());
134 errs() << BD.getToolName() << ": Error reading bitcode file '"
135 << BitcodeResult << "'!\n";
138 sys::fs::remove(BitcodeResult);
140 // Don't check if there are no passes in the suffix.
144 outs() << "Checking to see if '" << getPassesString(Suffix)
145 << "' passes compile correctly after the '"
146 << getPassesString(Prefix) << "' passes: ";
148 std::unique_ptr<Module> OriginalInput(
149 BD.swapProgramIn(PrefixOutput.release()));
150 if (BD.runPasses(BD.getProgram(), Suffix, BitcodeResult, false/*delete*/,
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());
160 Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "",
161 true /*delete bitcode*/, &Error);
163 return InternalError;
165 outs() << " nope.\n";
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());
177 class ReduceMiscompilingFunctions : public ListReducer<Function*> {
179 bool (*TestFn)(BugDriver &, Module *, Module *, std::string &);
181 ReduceMiscompilingFunctions(BugDriver &bd,
182 bool (*F)(BugDriver &, Module *, Module *,
184 : BD(bd), TestFn(F) {}
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);
192 return InternalError;
196 if (!Prefix.empty()) {
197 bool Ret = TestFuncs(Prefix, Error);
199 return InternalError;
206 bool TestFuncs(const std::vector<Function*> &Prefix, std::string &Error);
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.
217 static Module *TestMergedProgram(const BugDriver &BD, Module *M1, Module *M2,
218 bool DeleteInputs, std::string &Error,
220 // Link the two portions of the program back to together.
221 std::string ErrorMsg;
223 M1 = CloneModule(M1);
224 M2 = CloneModule(M2);
226 if (Linker::LinkModules(M1, M2, Linker::DestroySource, &ErrorMsg)) {
227 errs() << BD.getToolName() << ": Error linking modules together:"
231 delete M2; // We are done with this module.
233 // Execute the program.
234 Broken = BD.diffProgram(M1, "", "", false, &Error);
235 if (!Error.empty()) {
236 // Delete the linked module
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.
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);
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);
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);
275 // Split the module into the two halves of the program we want.
277 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
278 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, FuncsOnClone,
281 // Run the predicate, note that the predicate will delete both input modules.
282 bool Broken = TestFn(BD, ToOptimize, ToNotOptimize, Error);
284 delete BD.swapProgramIn(Orig);
289 /// DisambiguateGlobalSymbols - Give anonymous global values names.
291 static void DisambiguateGlobalSymbols(Module *M) {
292 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
295 I->setName("anon_global");
296 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
298 I->setName("anon_fn");
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.
305 static bool ExtractLoops(BugDriver &BD,
306 bool (*TestFn)(BugDriver &, Module *, Module *,
308 std::vector<Function*> &MiscompiledFunctions,
309 std::string &Error) {
310 bool MadeChange = false;
312 if (BugpointIsInterrupted) return MadeChange;
314 ValueToValueMapTy VMap;
315 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
316 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
317 MiscompiledFunctions,
319 Module *ToOptimizeLoopExtracted = BD.extractLoop(ToOptimize).release();
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;
328 errs() << "Extracted a loop from the breaking portion of the program.\n";
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
335 AbstractInterpreter *AI = BD.switchToSafeInterpreter();
337 Module *New = TestMergedProgram(BD, ToOptimizeLoopExtracted,
338 ToNotOptimize, false, Error, Failure);
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]]);
349 BD.switchToInterpreter(AI);
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";
356 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-tno.bc",
358 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to.bc",
360 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to-le.bc",
361 ToOptimizeLoopExtracted);
363 errs() << "Please submit the "
364 << OutputPrefix << "-loop-extract-fail-*.bc files.\n";
366 delete ToNotOptimize;
370 BD.switchToInterpreter(AI);
372 outs() << " Testing after loop extraction:\n";
373 // Clone modules, the tester function will free them.
374 Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted, VMap);
375 Module *TNOBackup = CloneModule(ToNotOptimize, VMap);
377 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
378 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
380 Failure = TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize, Error);
384 ToOptimizeLoopExtracted = TOLEBackup;
385 ToNotOptimize = TNOBackup;
388 outs() << "*** Loop extraction masked the problem. Undoing.\n";
389 // If the program is not still broken, then loop extraction did something
390 // that masked the error. Stop loop extraction now.
392 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
393 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) {
394 Function *F = MiscompiledFunctions[i];
395 MisCompFunctions.push_back(std::make_pair(F->getName(),
396 F->getFunctionType()));
399 std::string ErrorMsg;
400 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted,
401 Linker::DestroySource, &ErrorMsg)){
402 errs() << BD.getToolName() << ": Error linking modules together:"
407 MiscompiledFunctions.clear();
408 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
409 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
411 assert(NewF && "Function not found??");
412 MiscompiledFunctions.push_back(NewF);
415 delete ToOptimizeLoopExtracted;
416 BD.setNewProgram(ToNotOptimize);
420 outs() << "*** Loop extraction successful!\n";
422 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
423 for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
424 E = ToOptimizeLoopExtracted->end(); I != E; ++I)
425 if (!I->isDeclaration())
426 MisCompFunctions.push_back(std::make_pair(I->getName(),
427 I->getFunctionType()));
429 // Okay, great! Now we know that we extracted a loop and that loop
430 // extraction both didn't break the program, and didn't mask the problem.
431 // Replace the current program with the loop extracted version, and try to
432 // extract another loop.
433 std::string ErrorMsg;
434 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted,
435 Linker::DestroySource, &ErrorMsg)){
436 errs() << BD.getToolName() << ": Error linking modules together:"
440 delete ToOptimizeLoopExtracted;
442 // All of the Function*'s in the MiscompiledFunctions list are in the old
443 // module. Update this list to include all of the functions in the
444 // optimized and loop extracted module.
445 MiscompiledFunctions.clear();
446 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
447 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
449 assert(NewF && "Function not found??");
450 MiscompiledFunctions.push_back(NewF);
453 BD.setNewProgram(ToNotOptimize);
459 class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> {
461 bool (*TestFn)(BugDriver &, Module *, Module *, std::string &);
462 std::vector<Function*> FunctionsBeingTested;
464 ReduceMiscompiledBlocks(BugDriver &bd,
465 bool (*F)(BugDriver &, Module *, Module *,
467 const std::vector<Function*> &Fns)
468 : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {}
470 TestResult doTest(std::vector<BasicBlock*> &Prefix,
471 std::vector<BasicBlock*> &Suffix,
472 std::string &Error) override {
473 if (!Suffix.empty()) {
474 bool Ret = TestFuncs(Suffix, Error);
476 return InternalError;
480 if (!Prefix.empty()) {
481 bool Ret = TestFuncs(Prefix, Error);
483 return InternalError;
490 bool TestFuncs(const std::vector<BasicBlock*> &BBs, std::string &Error);
494 /// TestFuncs - Extract all blocks for the miscompiled functions except for the
495 /// specified blocks. If the problem still exists, return true.
497 bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs,
498 std::string &Error) {
499 // Test to see if the function is misoptimized if we ONLY run it on the
500 // functions listed in Funcs.
501 outs() << "Checking to see if the program is misoptimized when all ";
503 outs() << "but these " << BBs.size() << " blocks are extracted: ";
504 for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i)
505 outs() << BBs[i]->getName() << " ";
506 if (BBs.size() > 10) outs() << "...";
508 outs() << "blocks are extracted.";
512 // Split the module into the two halves of the program we want.
513 ValueToValueMapTy VMap;
514 Module *Clone = CloneModule(BD.getProgram(), VMap);
515 Module *Orig = BD.swapProgramIn(Clone);
516 std::vector<Function*> FuncsOnClone;
517 std::vector<BasicBlock*> BBsOnClone;
518 for (unsigned i = 0, e = FunctionsBeingTested.size(); i != e; ++i) {
519 Function *F = cast<Function>(VMap[FunctionsBeingTested[i]]);
520 FuncsOnClone.push_back(F);
522 for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
523 BasicBlock *BB = cast<BasicBlock>(VMap[BBs[i]]);
524 BBsOnClone.push_back(BB);
528 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
529 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
533 // Try the extraction. If it doesn't work, then the block extractor crashed
534 // or something, in which case bugpoint can't chase down this possibility.
535 if (std::unique_ptr<Module> New =
536 BD.extractMappedBlocksFromModule(BBsOnClone, ToOptimize)) {
538 // Run the predicate,
539 // note that the predicate will delete both input modules.
540 bool Ret = TestFn(BD, New.get(), ToNotOptimize, Error);
541 delete BD.swapProgramIn(Orig);
544 delete BD.swapProgramIn(Orig);
546 delete ToNotOptimize;
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
555 static bool ExtractBlocks(BugDriver &BD,
556 bool (*TestFn)(BugDriver &, Module *, Module *,
558 std::vector<Function*> &MiscompiledFunctions,
559 std::string &Error) {
560 if (BugpointIsInterrupted) return false;
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)
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();
573 // Check to see if all blocks are extractible first.
574 bool Ret = ReduceMiscompiledBlocks(BD, TestFn, MiscompiledFunctions)
575 .TestFuncs(std::vector<BasicBlock*>(), Error);
581 ReduceMiscompiledBlocks(BD, TestFn,
582 MiscompiledFunctions).reduceList(Blocks, Error);
585 if (Blocks.size() == OldSize)
589 ValueToValueMapTy VMap;
590 Module *ProgClone = CloneModule(BD.getProgram(), VMap);
591 Module *ToExtract = SplitFunctionsOutOfModule(ProgClone,
592 MiscompiledFunctions,
594 std::unique_ptr<Module> Extracted =
595 BD.extractMappedBlocksFromModule(Blocks, ToExtract);
597 // Weird, extraction should have worked.
598 errs() << "Nondeterministic problem extracting blocks??\n";
604 // Otherwise, block extraction succeeded. Link the two program fragments back
608 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
609 for (Module::iterator I = Extracted->begin(), E = Extracted->end();
611 if (!I->isDeclaration())
612 MisCompFunctions.push_back(std::make_pair(I->getName(),
613 I->getFunctionType()));
615 std::string ErrorMsg;
616 if (Linker::LinkModules(ProgClone, Extracted.get(), Linker::DestroySource,
618 errs() << BD.getToolName() << ": Error linking modules together:"
623 // Set the new program and delete the old one.
624 BD.setNewProgram(ProgClone);
626 // Update the list of miscompiled functions.
627 MiscompiledFunctions.clear();
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);
639 /// DebugAMiscompilation - This is a generic driver to narrow down
640 /// miscompilations, either in an optimization or a code generator.
642 static std::vector<Function*>
643 DebugAMiscompilation(BugDriver &BD,
644 bool (*TestFn)(BugDriver &, Module *, Module *,
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
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);
657 // Do the reduction...
658 if (!BugpointIsInterrupted)
659 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
661 if (!Error.empty()) {
662 errs() << "\n***Cannot reduce functions: ";
663 return MiscompiledFunctions;
665 outs() << "\n*** The following function"
666 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
667 << " being miscompiled: ";
668 PrintFunctionList(MiscompiledFunctions);
671 // See if we can rip any loops out of the miscompiled functions and still
672 // trigger the problem.
674 if (!BugpointIsInterrupted && !DisableLoopExtraction) {
675 bool Ret = ExtractLoops(BD, TestFn, MiscompiledFunctions, Error);
677 return MiscompiledFunctions;
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());
683 // Do the reduction...
684 if (!BugpointIsInterrupted)
685 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
688 return MiscompiledFunctions;
690 outs() << "\n*** The following function"
691 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
692 << " being miscompiled: ";
693 PrintFunctionList(MiscompiledFunctions);
698 if (!BugpointIsInterrupted && !DisableBlockExtraction) {
699 bool Ret = ExtractBlocks(BD, TestFn, MiscompiledFunctions, Error);
701 return MiscompiledFunctions;
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());
707 // Do the reduction...
708 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
711 return MiscompiledFunctions;
713 outs() << "\n*** The following function"
714 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
715 << " being miscompiled: ";
716 PrintFunctionList(MiscompiledFunctions);
721 return MiscompiledFunctions;
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.
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 std::unique_ptr<Module> Optimized = BD.runPassesOn(Test, BD.getPassesToRun(),
734 /*AutoDebugCrashes*/ true);
738 outs() << " Checking to see if the merged program executes correctly: ";
741 TestMergedProgram(BD, Optimized.get(), Safe, true, Error, Broken);
743 outs() << (Broken ? " nope.\n" : " yup.\n");
744 // Delete the original and set the new program.
745 delete BD.swapProgramIn(New);
751 /// debugMiscompilation - This method is used when the passes selected are not
752 /// crashing, but the generated output is semantically different from the
755 void BugDriver::debugMiscompilation(std::string *Error) {
756 // Make sure something was miscompiled...
757 if (!BugpointIsInterrupted)
758 if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun, *Error)) {
760 errs() << "*** Optimized program matches reference output! No problem"
761 << " detected...\nbugpoint can't help you with your problem!\n";
765 outs() << "\n*** Found miscompiling pass"
766 << (getPassesToRun().size() == 1 ? "" : "es") << ": "
767 << getPassesString(getPassesToRun()) << '\n';
768 EmitProgressBitcode(Program, "passinput");
770 std::vector<Function *> MiscompiledFunctions =
771 DebugAMiscompilation(*this, TestOptimizer, *Error);
775 // Output a bunch of bitcode files for the user...
776 outs() << "Outputting reduced bitcode files which expose the problem:\n";
777 ValueToValueMapTy VMap;
778 Module *ToNotOptimize = CloneModule(getProgram(), VMap);
779 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
780 MiscompiledFunctions,
783 outs() << " Non-optimized portion: ";
784 EmitProgressBitcode(ToNotOptimize, "tonotoptimize", true);
785 delete ToNotOptimize; // Delete hacked module.
787 outs() << " Portion that is input to optimizer: ";
788 EmitProgressBitcode(ToOptimize, "tooptimize");
789 delete ToOptimize; // Delete hacked module.
794 /// CleanupAndPrepareModules - Get the specified modules ready for code
795 /// generator testing.
797 static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
799 // Clean up the modules, removing extra cruft that we don't need anymore...
800 Test = BD.performFinalCleanups(Test).release();
802 // If we are executing the JIT, we have several nasty issues to take care of.
803 if (!BD.isExecutingJIT()) return;
805 // First, if the main function is in the Safe module, we must add a stub to
806 // the Test module to call into it. Thus, we create a new function `main'
807 // which just calls the old one.
808 if (Function *oldMain = Safe->getFunction("main"))
809 if (!oldMain->isDeclaration()) {
811 oldMain->setName("llvm_bugpoint_old_main");
812 // Create a NEW `main' function with same type in the test module.
813 Function *newMain = Function::Create(oldMain->getFunctionType(),
814 GlobalValue::ExternalLinkage,
816 // Create an `oldmain' prototype in the test module, which will
817 // corresponds to the real main function in the same module.
818 Function *oldMainProto = Function::Create(oldMain->getFunctionType(),
819 GlobalValue::ExternalLinkage,
820 oldMain->getName(), Test);
821 // Set up and remember the argument list for the main function.
822 std::vector<Value*> args;
823 for (Function::arg_iterator
824 I = newMain->arg_begin(), E = newMain->arg_end(),
825 OI = oldMain->arg_begin(); I != E; ++I, ++OI) {
826 I->setName(OI->getName()); // Copy argument names from oldMain
830 // Call the old main function and return its result
831 BasicBlock *BB = BasicBlock::Create(Safe->getContext(), "entry", newMain);
832 CallInst *call = CallInst::Create(oldMainProto, args, "", BB);
834 // If the type of old function wasn't void, return value of call
835 ReturnInst::Create(Safe->getContext(), call, BB);
838 // The second nasty issue we must deal with in the JIT is that the Safe
839 // module cannot directly reference any functions defined in the test
840 // module. Instead, we use a JIT API call to dynamically resolve the
843 // Add the resolver to the Safe module.
844 // Prototype: void *getPointerToNamedFunction(const char* Name)
845 Constant *resolverFunc =
846 Safe->getOrInsertFunction("getPointerToNamedFunction",
847 Type::getInt8PtrTy(Safe->getContext()),
848 Type::getInt8PtrTy(Safe->getContext()),
851 // Use the function we just added to get addresses of functions we need.
852 for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) {
853 if (F->isDeclaration() && !F->use_empty() && &*F != resolverFunc &&
854 !F->isIntrinsic() /* ignore intrinsics */) {
855 Function *TestFn = Test->getFunction(F->getName());
857 // Don't forward functions which are external in the test module too.
858 if (TestFn && !TestFn->isDeclaration()) {
859 // 1. Add a string constant with its name to the global file
860 Constant *InitArray =
861 ConstantDataArray::getString(F->getContext(), F->getName());
862 GlobalVariable *funcName =
863 new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/,
864 GlobalValue::InternalLinkage, InitArray,
865 F->getName() + "_name");
867 // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
868 // sbyte* so it matches the signature of the resolver function.
870 // GetElementPtr *funcName, ulong 0, ulong 0
871 std::vector<Constant*> GEPargs(2,
872 Constant::getNullValue(Type::getInt32Ty(F->getContext())));
873 Value *GEP = ConstantExpr::getGetElementPtr(funcName, GEPargs);
874 std::vector<Value*> ResolverArgs;
875 ResolverArgs.push_back(GEP);
877 // Rewrite uses of F in global initializers, etc. to uses of a wrapper
878 // function that dynamically resolves the calls to F via our JIT API
879 if (!F->use_empty()) {
880 // Create a new global to hold the cached function pointer.
881 Constant *NullPtr = ConstantPointerNull::get(F->getType());
882 GlobalVariable *Cache =
883 new GlobalVariable(*F->getParent(), F->getType(),
884 false, GlobalValue::InternalLinkage,
885 NullPtr,F->getName()+".fpcache");
887 // Construct a new stub function that will re-route calls to F
888 FunctionType *FuncTy = F->getFunctionType();
889 Function *FuncWrapper = Function::Create(FuncTy,
890 GlobalValue::InternalLinkage,
891 F->getName() + "_wrapper",
893 BasicBlock *EntryBB = BasicBlock::Create(F->getContext(),
894 "entry", FuncWrapper);
895 BasicBlock *DoCallBB = BasicBlock::Create(F->getContext(),
896 "usecache", FuncWrapper);
897 BasicBlock *LookupBB = BasicBlock::Create(F->getContext(),
898 "lookupfp", FuncWrapper);
900 // Check to see if we already looked up the value.
901 Value *CachedVal = new LoadInst(Cache, "fpcache", EntryBB);
902 Value *IsNull = new ICmpInst(*EntryBB, ICmpInst::ICMP_EQ, CachedVal,
904 BranchInst::Create(LookupBB, DoCallBB, IsNull, EntryBB);
906 // Resolve the call to function F via the JIT API:
908 // call resolver(GetElementPtr...)
910 CallInst::Create(resolverFunc, ResolverArgs, "resolver", LookupBB);
912 // Cast the result from the resolver to correctly-typed function.
913 CastInst *CastedResolver =
914 new BitCastInst(Resolver,
915 PointerType::getUnqual(F->getFunctionType()),
916 "resolverCast", LookupBB);
918 // Save the value in our cache.
919 new StoreInst(CastedResolver, Cache, LookupBB);
920 BranchInst::Create(DoCallBB, LookupBB);
922 PHINode *FuncPtr = PHINode::Create(NullPtr->getType(), 2,
924 FuncPtr->addIncoming(CastedResolver, LookupBB);
925 FuncPtr->addIncoming(CachedVal, EntryBB);
927 // Save the argument list.
928 std::vector<Value*> Args;
929 for (Function::arg_iterator i = FuncWrapper->arg_begin(),
930 e = FuncWrapper->arg_end(); i != e; ++i)
933 // Pass on the arguments to the real function, return its result
934 if (F->getReturnType()->isVoidTy()) {
935 CallInst::Create(FuncPtr, Args, "", DoCallBB);
936 ReturnInst::Create(F->getContext(), DoCallBB);
938 CallInst *Call = CallInst::Create(FuncPtr, Args,
940 ReturnInst::Create(F->getContext(),Call, DoCallBB);
943 // Use the wrapper function instead of the old function
944 F->replaceAllUsesWith(FuncWrapper);
950 if (verifyModule(*Test) || verifyModule(*Safe)) {
951 errs() << "Bugpoint has a bug, which corrupted a module!!\n";
958 /// TestCodeGenerator - This is the predicate function used to check to see if
959 /// the "Test" portion of the program is miscompiled by the code generator under
960 /// test. If so, return true. In any case, both module arguments are deleted.
962 static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe,
963 std::string &Error) {
964 CleanupAndPrepareModules(BD, Test, Safe);
966 SmallString<128> TestModuleBC;
968 std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
969 TestModuleFD, TestModuleBC);
971 errs() << BD.getToolName() << "Error making unique filename: "
972 << EC.message() << "\n";
975 if (BD.writeProgramToFile(TestModuleBC.str(), TestModuleFD, Test)) {
976 errs() << "Error writing bitcode to `" << TestModuleBC.str()
982 FileRemover TestModuleBCRemover(TestModuleBC.str(), !SaveTemps);
984 // Make the shared library
985 SmallString<128> SafeModuleBC;
987 EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD,
990 errs() << BD.getToolName() << "Error making unique filename: "
991 << EC.message() << "\n";
995 if (BD.writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, Safe)) {
996 errs() << "Error writing bitcode to `" << SafeModuleBC.str()
1001 FileRemover SafeModuleBCRemover(SafeModuleBC.str(), !SaveTemps);
1003 std::string SharedObject = BD.compileSharedObject(SafeModuleBC.str(), Error);
1008 FileRemover SharedObjectRemover(SharedObject, !SaveTemps);
1010 // Run the code generator on the `Test' code, loading the shared library.
1011 // The function returns whether or not the new output differs from reference.
1012 bool Result = BD.diffProgram(BD.getProgram(), TestModuleBC.str(),
1013 SharedObject, false, &Error);
1018 errs() << ": still failing!\n";
1020 errs() << ": didn't fail.\n";
1026 /// debugCodeGenerator - debug errors in LLC, LLI, or CBE.
1028 bool BugDriver::debugCodeGenerator(std::string *Error) {
1029 if ((void*)SafeInterpreter == (void*)Interpreter) {
1030 std::string Result = executeProgramSafely(Program, "bugpoint.safe.out",
1032 if (Error->empty()) {
1033 outs() << "\n*** The \"safe\" i.e. 'known good' backend cannot match "
1034 << "the reference diff. This may be due to a\n front-end "
1035 << "bug or a bug in the original program, but this can also "
1036 << "happen if bugpoint isn't running the program with the "
1037 << "right flags or input.\n I left the result of executing "
1038 << "the program with the \"safe\" backend in this file for "
1040 << Result << "'.\n";
1045 DisambiguateGlobalSymbols(Program);
1047 std::vector<Function*> Funcs = DebugAMiscompilation(*this, TestCodeGenerator,
1049 if (!Error->empty())
1052 // Split the module into the two halves of the program we want.
1053 ValueToValueMapTy VMap;
1054 Module *ToNotCodeGen = CloneModule(getProgram(), VMap);
1055 Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs, VMap);
1057 // Condition the modules
1058 CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen);
1060 SmallString<128> TestModuleBC;
1062 std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
1063 TestModuleFD, TestModuleBC);
1065 errs() << getToolName() << "Error making unique filename: "
1066 << EC.message() << "\n";
1070 if (writeProgramToFile(TestModuleBC.str(), TestModuleFD, ToCodeGen)) {
1071 errs() << "Error writing bitcode to `" << TestModuleBC.str()
1077 // Make the shared library
1078 SmallString<128> SafeModuleBC;
1080 EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD,
1083 errs() << getToolName() << "Error making unique filename: "
1084 << EC.message() << "\n";
1088 if (writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, ToNotCodeGen)) {
1089 errs() << "Error writing bitcode to `" << SafeModuleBC.str()
1093 std::string SharedObject = compileSharedObject(SafeModuleBC.str(), *Error);
1094 if (!Error->empty())
1096 delete ToNotCodeGen;
1098 outs() << "You can reproduce the problem with the command line: \n";
1099 if (isExecutingJIT()) {
1100 outs() << " lli -load " << SharedObject << " " << TestModuleBC.str();
1102 outs() << " llc " << TestModuleBC.str() << " -o " << TestModuleBC.str()
1104 outs() << " gcc " << SharedObject << " " << TestModuleBC.str()
1105 << ".s -o " << TestModuleBC.str() << ".exe";
1106 #if defined (HAVE_LINK_R)
1107 outs() << " -Wl,-R.";
1110 outs() << " " << TestModuleBC.str() << ".exe";
1112 for (unsigned i = 0, e = InputArgv.size(); i != e; ++i)
1113 outs() << " " << InputArgv[i];
1115 outs() << "The shared object was created with:\n llc -march=c "
1116 << SafeModuleBC.str() << " -o temporary.c\n"
1117 << " gcc -xc temporary.c -O2 -o " << SharedObject;
1118 if (TargetTriple.getArch() == Triple::sparc)
1119 outs() << " -G"; // Compile a shared library, `-G' for Sparc
1121 outs() << " -fPIC -shared"; // `-shared' for Linux/X86, maybe others
1123 outs() << " -fno-strict-aliasing\n";