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.
222 M1 = CloneModule(M1);
223 M2 = CloneModule(M2);
225 if (Linker::LinkModules(M1, M2))
227 delete M2; // We are done with this module.
229 // Execute the program.
230 Broken = BD.diffProgram(M1, "", "", false, &Error);
231 if (!Error.empty()) {
232 // Delete the linked module
239 /// TestFuncs - split functions in a Module into two groups: those that are
240 /// under consideration for miscompilation vs. those that are not, and test
241 /// accordingly. Each group of functions becomes a separate Module.
243 bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs,
244 std::string &Error) {
245 // Test to see if the function is misoptimized if we ONLY run it on the
246 // functions listed in Funcs.
247 outs() << "Checking to see if the program is misoptimized when "
248 << (Funcs.size()==1 ? "this function is" : "these functions are")
249 << " run through the pass"
250 << (BD.getPassesToRun().size() == 1 ? "" : "es") << ":";
251 PrintFunctionList(Funcs);
254 // Create a clone for two reasons:
255 // * If the optimization passes delete any function, the deleted function
256 // will be in the clone and Funcs will still point to valid memory
257 // * If the optimization passes use interprocedural information to break
258 // a function, we want to continue with the original function. Otherwise
259 // we can conclude that a function triggers the bug when in fact one
260 // needs a larger set of original functions to do so.
261 ValueToValueMapTy VMap;
262 Module *Clone = CloneModule(BD.getProgram(), VMap);
263 Module *Orig = BD.swapProgramIn(Clone);
265 std::vector<Function*> FuncsOnClone;
266 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
267 Function *F = cast<Function>(VMap[Funcs[i]]);
268 FuncsOnClone.push_back(F);
271 // Split the module into the two halves of the program we want.
273 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
274 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, FuncsOnClone,
277 // Run the predicate, note that the predicate will delete both input modules.
278 bool Broken = TestFn(BD, ToOptimize, ToNotOptimize, Error);
280 delete BD.swapProgramIn(Orig);
285 /// DisambiguateGlobalSymbols - Give anonymous global values names.
287 static void DisambiguateGlobalSymbols(Module *M) {
288 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
291 I->setName("anon_global");
292 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
294 I->setName("anon_fn");
297 /// ExtractLoops - Given a reduced list of functions that still exposed the bug,
298 /// check to see if we can extract the loops in the region without obscuring the
299 /// bug. If so, it reduces the amount of code identified.
301 static bool ExtractLoops(BugDriver &BD,
302 bool (*TestFn)(BugDriver &, Module *, Module *,
304 std::vector<Function*> &MiscompiledFunctions,
305 std::string &Error) {
306 bool MadeChange = false;
308 if (BugpointIsInterrupted) return MadeChange;
310 ValueToValueMapTy VMap;
311 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
312 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
313 MiscompiledFunctions,
315 Module *ToOptimizeLoopExtracted = BD.extractLoop(ToOptimize).release();
316 if (!ToOptimizeLoopExtracted) {
317 // If the loop extractor crashed or if there were no extractible loops,
318 // then this chapter of our odyssey is over with.
319 delete ToNotOptimize;
324 errs() << "Extracted a loop from the breaking portion of the program.\n";
326 // Bugpoint is intentionally not very trusting of LLVM transformations. In
327 // particular, we're not going to assume that the loop extractor works, so
328 // we're going to test the newly loop extracted program to make sure nothing
329 // has broken. If something broke, then we'll inform the user and stop
331 AbstractInterpreter *AI = BD.switchToSafeInterpreter();
333 Module *New = TestMergedProgram(BD, ToOptimizeLoopExtracted,
334 ToNotOptimize, false, Error, Failure);
338 // Delete the original and set the new program.
339 Module *Old = BD.swapProgramIn(New);
340 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
341 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
345 BD.switchToInterpreter(AI);
347 // Merged program doesn't work anymore!
348 errs() << " *** ERROR: Loop extraction broke the program. :("
349 << " Please report a bug!\n";
350 errs() << " Continuing on with un-loop-extracted version.\n";
352 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-tno.bc",
354 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to.bc",
356 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to-le.bc",
357 ToOptimizeLoopExtracted);
359 errs() << "Please submit the "
360 << OutputPrefix << "-loop-extract-fail-*.bc files.\n";
362 delete ToNotOptimize;
366 BD.switchToInterpreter(AI);
368 outs() << " Testing after loop extraction:\n";
369 // Clone modules, the tester function will free them.
370 Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted, VMap);
371 Module *TNOBackup = CloneModule(ToNotOptimize, VMap);
373 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
374 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
376 Failure = TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize, Error);
380 ToOptimizeLoopExtracted = TOLEBackup;
381 ToNotOptimize = TNOBackup;
384 outs() << "*** Loop extraction masked the problem. Undoing.\n";
385 // If the program is not still broken, then loop extraction did something
386 // that masked the error. Stop loop extraction now.
388 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
389 for (Function *F : MiscompiledFunctions) {
390 MisCompFunctions.emplace_back(F->getName(), F->getFunctionType());
393 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted))
396 MiscompiledFunctions.clear();
397 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
398 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
400 assert(NewF && "Function not found??");
401 MiscompiledFunctions.push_back(NewF);
404 delete ToOptimizeLoopExtracted;
405 BD.setNewProgram(ToNotOptimize);
409 outs() << "*** Loop extraction successful!\n";
411 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
412 for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
413 E = ToOptimizeLoopExtracted->end(); I != E; ++I)
414 if (!I->isDeclaration())
415 MisCompFunctions.emplace_back(I->getName(), I->getFunctionType());
417 // Okay, great! Now we know that we extracted a loop and that loop
418 // extraction both didn't break the program, and didn't mask the problem.
419 // Replace the current program with the loop extracted version, and try to
420 // extract another loop.
421 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted))
424 delete ToOptimizeLoopExtracted;
426 // All of the Function*'s in the MiscompiledFunctions list are in the old
427 // module. Update this list to include all of the functions in the
428 // optimized and loop extracted module.
429 MiscompiledFunctions.clear();
430 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
431 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
433 assert(NewF && "Function not found??");
434 MiscompiledFunctions.push_back(NewF);
437 BD.setNewProgram(ToNotOptimize);
443 class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> {
445 bool (*TestFn)(BugDriver &, Module *, Module *, std::string &);
446 std::vector<Function*> FunctionsBeingTested;
448 ReduceMiscompiledBlocks(BugDriver &bd,
449 bool (*F)(BugDriver &, Module *, Module *,
451 const std::vector<Function*> &Fns)
452 : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {}
454 TestResult doTest(std::vector<BasicBlock*> &Prefix,
455 std::vector<BasicBlock*> &Suffix,
456 std::string &Error) override {
457 if (!Suffix.empty()) {
458 bool Ret = TestFuncs(Suffix, Error);
460 return InternalError;
464 if (!Prefix.empty()) {
465 bool Ret = TestFuncs(Prefix, Error);
467 return InternalError;
474 bool TestFuncs(const std::vector<BasicBlock*> &BBs, std::string &Error);
478 /// TestFuncs - Extract all blocks for the miscompiled functions except for the
479 /// specified blocks. If the problem still exists, return true.
481 bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs,
482 std::string &Error) {
483 // Test to see if the function is misoptimized if we ONLY run it on the
484 // functions listed in Funcs.
485 outs() << "Checking to see if the program is misoptimized when all ";
487 outs() << "but these " << BBs.size() << " blocks are extracted: ";
488 for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i)
489 outs() << BBs[i]->getName() << " ";
490 if (BBs.size() > 10) outs() << "...";
492 outs() << "blocks are extracted.";
496 // Split the module into the two halves of the program we want.
497 ValueToValueMapTy VMap;
498 Module *Clone = CloneModule(BD.getProgram(), VMap);
499 Module *Orig = BD.swapProgramIn(Clone);
500 std::vector<Function*> FuncsOnClone;
501 std::vector<BasicBlock*> BBsOnClone;
502 for (unsigned i = 0, e = FunctionsBeingTested.size(); i != e; ++i) {
503 Function *F = cast<Function>(VMap[FunctionsBeingTested[i]]);
504 FuncsOnClone.push_back(F);
506 for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
507 BasicBlock *BB = cast<BasicBlock>(VMap[BBs[i]]);
508 BBsOnClone.push_back(BB);
512 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
513 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
517 // Try the extraction. If it doesn't work, then the block extractor crashed
518 // or something, in which case bugpoint can't chase down this possibility.
519 if (std::unique_ptr<Module> New =
520 BD.extractMappedBlocksFromModule(BBsOnClone, ToOptimize)) {
522 // Run the predicate,
523 // note that the predicate will delete both input modules.
524 bool Ret = TestFn(BD, New.get(), ToNotOptimize, Error);
525 delete BD.swapProgramIn(Orig);
528 delete BD.swapProgramIn(Orig);
530 delete ToNotOptimize;
535 /// ExtractBlocks - Given a reduced list of functions that still expose the bug,
536 /// extract as many basic blocks from the region as possible without obscuring
539 static bool ExtractBlocks(BugDriver &BD,
540 bool (*TestFn)(BugDriver &, Module *, Module *,
542 std::vector<Function*> &MiscompiledFunctions,
543 std::string &Error) {
544 if (BugpointIsInterrupted) return false;
546 std::vector<BasicBlock*> Blocks;
547 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
548 for (Function::iterator I = MiscompiledFunctions[i]->begin(),
549 E = MiscompiledFunctions[i]->end(); I != E; ++I)
552 // Use the list reducer to identify blocks that can be extracted without
553 // obscuring the bug. The Blocks list will end up containing blocks that must
554 // be retained from the original program.
555 unsigned OldSize = Blocks.size();
557 // Check to see if all blocks are extractible first.
558 bool Ret = ReduceMiscompiledBlocks(BD, TestFn, MiscompiledFunctions)
559 .TestFuncs(std::vector<BasicBlock*>(), Error);
565 ReduceMiscompiledBlocks(BD, TestFn,
566 MiscompiledFunctions).reduceList(Blocks, Error);
569 if (Blocks.size() == OldSize)
573 ValueToValueMapTy VMap;
574 Module *ProgClone = CloneModule(BD.getProgram(), VMap);
575 Module *ToExtract = SplitFunctionsOutOfModule(ProgClone,
576 MiscompiledFunctions,
578 std::unique_ptr<Module> Extracted =
579 BD.extractMappedBlocksFromModule(Blocks, ToExtract);
581 // Weird, extraction should have worked.
582 errs() << "Nondeterministic problem extracting blocks??\n";
588 // Otherwise, block extraction succeeded. Link the two program fragments back
592 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
593 for (Module::iterator I = Extracted->begin(), E = Extracted->end();
595 if (!I->isDeclaration())
596 MisCompFunctions.emplace_back(I->getName(), I->getFunctionType());
598 if (Linker::LinkModules(ProgClone, Extracted.get()))
601 // Set the new program and delete the old one.
602 BD.setNewProgram(ProgClone);
604 // Update the list of miscompiled functions.
605 MiscompiledFunctions.clear();
607 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
608 Function *NewF = ProgClone->getFunction(MisCompFunctions[i].first);
609 assert(NewF && "Function not found??");
610 MiscompiledFunctions.push_back(NewF);
617 /// DebugAMiscompilation - This is a generic driver to narrow down
618 /// miscompilations, either in an optimization or a code generator.
620 static std::vector<Function*>
621 DebugAMiscompilation(BugDriver &BD,
622 bool (*TestFn)(BugDriver &, Module *, Module *,
624 std::string &Error) {
625 // Okay, now that we have reduced the list of passes which are causing the
626 // failure, see if we can pin down which functions are being
627 // miscompiled... first build a list of all of the non-external functions in
629 std::vector<Function*> MiscompiledFunctions;
630 Module *Prog = BD.getProgram();
631 for (Module::iterator I = Prog->begin(), E = Prog->end(); I != E; ++I)
632 if (!I->isDeclaration())
633 MiscompiledFunctions.push_back(I);
635 // Do the reduction...
636 if (!BugpointIsInterrupted)
637 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
639 if (!Error.empty()) {
640 errs() << "\n***Cannot reduce functions: ";
641 return MiscompiledFunctions;
643 outs() << "\n*** The following function"
644 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
645 << " being miscompiled: ";
646 PrintFunctionList(MiscompiledFunctions);
649 // See if we can rip any loops out of the miscompiled functions and still
650 // trigger the problem.
652 if (!BugpointIsInterrupted && !DisableLoopExtraction) {
653 bool Ret = ExtractLoops(BD, TestFn, MiscompiledFunctions, Error);
655 return MiscompiledFunctions;
657 // Okay, we extracted some loops and the problem still appears. See if
658 // we can eliminate some of the created functions from being candidates.
659 DisambiguateGlobalSymbols(BD.getProgram());
661 // Do the reduction...
662 if (!BugpointIsInterrupted)
663 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
666 return MiscompiledFunctions;
668 outs() << "\n*** The following function"
669 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
670 << " being miscompiled: ";
671 PrintFunctionList(MiscompiledFunctions);
676 if (!BugpointIsInterrupted && !DisableBlockExtraction) {
677 bool Ret = ExtractBlocks(BD, TestFn, MiscompiledFunctions, Error);
679 return MiscompiledFunctions;
681 // Okay, we extracted some blocks and the problem still appears. See if
682 // we can eliminate some of the created functions from being candidates.
683 DisambiguateGlobalSymbols(BD.getProgram());
685 // Do the reduction...
686 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
689 return MiscompiledFunctions;
691 outs() << "\n*** The following function"
692 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
693 << " being miscompiled: ";
694 PrintFunctionList(MiscompiledFunctions);
699 return MiscompiledFunctions;
702 /// TestOptimizer - This is the predicate function used to check to see if the
703 /// "Test" portion of the program is misoptimized. If so, return true. In any
704 /// case, both module arguments are deleted.
706 static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe,
707 std::string &Error) {
708 // Run the optimization passes on ToOptimize, producing a transformed version
709 // of the functions being tested.
710 outs() << " Optimizing functions being tested: ";
711 std::unique_ptr<Module> Optimized = BD.runPassesOn(Test, BD.getPassesToRun(),
712 /*AutoDebugCrashes*/ true);
716 outs() << " Checking to see if the merged program executes correctly: ";
719 TestMergedProgram(BD, Optimized.get(), Safe, true, Error, Broken);
721 outs() << (Broken ? " nope.\n" : " yup.\n");
722 // Delete the original and set the new program.
723 delete BD.swapProgramIn(New);
729 /// debugMiscompilation - This method is used when the passes selected are not
730 /// crashing, but the generated output is semantically different from the
733 void BugDriver::debugMiscompilation(std::string *Error) {
734 // Make sure something was miscompiled...
735 if (!BugpointIsInterrupted)
736 if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun, *Error)) {
738 errs() << "*** Optimized program matches reference output! No problem"
739 << " detected...\nbugpoint can't help you with your problem!\n";
743 outs() << "\n*** Found miscompiling pass"
744 << (getPassesToRun().size() == 1 ? "" : "es") << ": "
745 << getPassesString(getPassesToRun()) << '\n';
746 EmitProgressBitcode(Program, "passinput");
748 std::vector<Function *> MiscompiledFunctions =
749 DebugAMiscompilation(*this, TestOptimizer, *Error);
753 // Output a bunch of bitcode files for the user...
754 outs() << "Outputting reduced bitcode files which expose the problem:\n";
755 ValueToValueMapTy VMap;
756 Module *ToNotOptimize = CloneModule(getProgram(), VMap);
757 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
758 MiscompiledFunctions,
761 outs() << " Non-optimized portion: ";
762 EmitProgressBitcode(ToNotOptimize, "tonotoptimize", true);
763 delete ToNotOptimize; // Delete hacked module.
765 outs() << " Portion that is input to optimizer: ";
766 EmitProgressBitcode(ToOptimize, "tooptimize");
767 delete ToOptimize; // Delete hacked module.
772 /// CleanupAndPrepareModules - Get the specified modules ready for code
773 /// generator testing.
775 static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
777 // Clean up the modules, removing extra cruft that we don't need anymore...
778 Test = BD.performFinalCleanups(Test).release();
780 // If we are executing the JIT, we have several nasty issues to take care of.
781 if (!BD.isExecutingJIT()) return;
783 // First, if the main function is in the Safe module, we must add a stub to
784 // the Test module to call into it. Thus, we create a new function `main'
785 // which just calls the old one.
786 if (Function *oldMain = Safe->getFunction("main"))
787 if (!oldMain->isDeclaration()) {
789 oldMain->setName("llvm_bugpoint_old_main");
790 // Create a NEW `main' function with same type in the test module.
791 Function *newMain = Function::Create(oldMain->getFunctionType(),
792 GlobalValue::ExternalLinkage,
794 // Create an `oldmain' prototype in the test module, which will
795 // corresponds to the real main function in the same module.
796 Function *oldMainProto = Function::Create(oldMain->getFunctionType(),
797 GlobalValue::ExternalLinkage,
798 oldMain->getName(), Test);
799 // Set up and remember the argument list for the main function.
800 std::vector<Value*> args;
801 for (Function::arg_iterator
802 I = newMain->arg_begin(), E = newMain->arg_end(),
803 OI = oldMain->arg_begin(); I != E; ++I, ++OI) {
804 I->setName(OI->getName()); // Copy argument names from oldMain
808 // Call the old main function and return its result
809 BasicBlock *BB = BasicBlock::Create(Safe->getContext(), "entry", newMain);
810 CallInst *call = CallInst::Create(oldMainProto, args, "", BB);
812 // If the type of old function wasn't void, return value of call
813 ReturnInst::Create(Safe->getContext(), call, BB);
816 // The second nasty issue we must deal with in the JIT is that the Safe
817 // module cannot directly reference any functions defined in the test
818 // module. Instead, we use a JIT API call to dynamically resolve the
821 // Add the resolver to the Safe module.
822 // Prototype: void *getPointerToNamedFunction(const char* Name)
823 Constant *resolverFunc =
824 Safe->getOrInsertFunction("getPointerToNamedFunction",
825 Type::getInt8PtrTy(Safe->getContext()),
826 Type::getInt8PtrTy(Safe->getContext()),
829 // Use the function we just added to get addresses of functions we need.
830 for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) {
831 if (F->isDeclaration() && !F->use_empty() && &*F != resolverFunc &&
832 !F->isIntrinsic() /* ignore intrinsics */) {
833 Function *TestFn = Test->getFunction(F->getName());
835 // Don't forward functions which are external in the test module too.
836 if (TestFn && !TestFn->isDeclaration()) {
837 // 1. Add a string constant with its name to the global file
838 Constant *InitArray =
839 ConstantDataArray::getString(F->getContext(), F->getName());
840 GlobalVariable *funcName =
841 new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/,
842 GlobalValue::InternalLinkage, InitArray,
843 F->getName() + "_name");
845 // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
846 // sbyte* so it matches the signature of the resolver function.
848 // GetElementPtr *funcName, ulong 0, ulong 0
849 std::vector<Constant*> GEPargs(2,
850 Constant::getNullValue(Type::getInt32Ty(F->getContext())));
851 Value *GEP = ConstantExpr::getGetElementPtr(InitArray->getType(),
853 std::vector<Value*> ResolverArgs;
854 ResolverArgs.push_back(GEP);
856 // Rewrite uses of F in global initializers, etc. to uses of a wrapper
857 // function that dynamically resolves the calls to F via our JIT API
858 if (!F->use_empty()) {
859 // Create a new global to hold the cached function pointer.
860 Constant *NullPtr = ConstantPointerNull::get(F->getType());
861 GlobalVariable *Cache =
862 new GlobalVariable(*F->getParent(), F->getType(),
863 false, GlobalValue::InternalLinkage,
864 NullPtr,F->getName()+".fpcache");
866 // Construct a new stub function that will re-route calls to F
867 FunctionType *FuncTy = F->getFunctionType();
868 Function *FuncWrapper = Function::Create(FuncTy,
869 GlobalValue::InternalLinkage,
870 F->getName() + "_wrapper",
872 BasicBlock *EntryBB = BasicBlock::Create(F->getContext(),
873 "entry", FuncWrapper);
874 BasicBlock *DoCallBB = BasicBlock::Create(F->getContext(),
875 "usecache", FuncWrapper);
876 BasicBlock *LookupBB = BasicBlock::Create(F->getContext(),
877 "lookupfp", FuncWrapper);
879 // Check to see if we already looked up the value.
880 Value *CachedVal = new LoadInst(Cache, "fpcache", EntryBB);
881 Value *IsNull = new ICmpInst(*EntryBB, ICmpInst::ICMP_EQ, CachedVal,
883 BranchInst::Create(LookupBB, DoCallBB, IsNull, EntryBB);
885 // Resolve the call to function F via the JIT API:
887 // call resolver(GetElementPtr...)
889 CallInst::Create(resolverFunc, ResolverArgs, "resolver", LookupBB);
891 // Cast the result from the resolver to correctly-typed function.
892 CastInst *CastedResolver =
893 new BitCastInst(Resolver,
894 PointerType::getUnqual(F->getFunctionType()),
895 "resolverCast", LookupBB);
897 // Save the value in our cache.
898 new StoreInst(CastedResolver, Cache, LookupBB);
899 BranchInst::Create(DoCallBB, LookupBB);
901 PHINode *FuncPtr = PHINode::Create(NullPtr->getType(), 2,
903 FuncPtr->addIncoming(CastedResolver, LookupBB);
904 FuncPtr->addIncoming(CachedVal, EntryBB);
906 // Save the argument list.
907 std::vector<Value*> Args;
908 for (Function::arg_iterator i = FuncWrapper->arg_begin(),
909 e = FuncWrapper->arg_end(); i != e; ++i)
912 // Pass on the arguments to the real function, return its result
913 if (F->getReturnType()->isVoidTy()) {
914 CallInst::Create(FuncPtr, Args, "", DoCallBB);
915 ReturnInst::Create(F->getContext(), DoCallBB);
917 CallInst *Call = CallInst::Create(FuncPtr, Args,
919 ReturnInst::Create(F->getContext(),Call, DoCallBB);
922 // Use the wrapper function instead of the old function
923 F->replaceAllUsesWith(FuncWrapper);
929 if (verifyModule(*Test) || verifyModule(*Safe)) {
930 errs() << "Bugpoint has a bug, which corrupted a module!!\n";
937 /// TestCodeGenerator - This is the predicate function used to check to see if
938 /// the "Test" portion of the program is miscompiled by the code generator under
939 /// test. If so, return true. In any case, both module arguments are deleted.
941 static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe,
942 std::string &Error) {
943 CleanupAndPrepareModules(BD, Test, Safe);
945 SmallString<128> TestModuleBC;
947 std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
948 TestModuleFD, TestModuleBC);
950 errs() << BD.getToolName() << "Error making unique filename: "
951 << EC.message() << "\n";
954 if (BD.writeProgramToFile(TestModuleBC.str(), TestModuleFD, Test)) {
955 errs() << "Error writing bitcode to `" << TestModuleBC.str()
961 FileRemover TestModuleBCRemover(TestModuleBC.str(), !SaveTemps);
963 // Make the shared library
964 SmallString<128> SafeModuleBC;
966 EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD,
969 errs() << BD.getToolName() << "Error making unique filename: "
970 << EC.message() << "\n";
974 if (BD.writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, Safe)) {
975 errs() << "Error writing bitcode to `" << SafeModuleBC
980 FileRemover SafeModuleBCRemover(SafeModuleBC.str(), !SaveTemps);
982 std::string SharedObject = BD.compileSharedObject(SafeModuleBC.str(), Error);
987 FileRemover SharedObjectRemover(SharedObject, !SaveTemps);
989 // Run the code generator on the `Test' code, loading the shared library.
990 // The function returns whether or not the new output differs from reference.
991 bool Result = BD.diffProgram(BD.getProgram(), TestModuleBC.str(),
992 SharedObject, false, &Error);
997 errs() << ": still failing!\n";
999 errs() << ": didn't fail.\n";
1005 /// debugCodeGenerator - debug errors in LLC, LLI, or CBE.
1007 bool BugDriver::debugCodeGenerator(std::string *Error) {
1008 if ((void*)SafeInterpreter == (void*)Interpreter) {
1009 std::string Result = executeProgramSafely(Program, "bugpoint.safe.out",
1011 if (Error->empty()) {
1012 outs() << "\n*** The \"safe\" i.e. 'known good' backend cannot match "
1013 << "the reference diff. This may be due to a\n front-end "
1014 << "bug or a bug in the original program, but this can also "
1015 << "happen if bugpoint isn't running the program with the "
1016 << "right flags or input.\n I left the result of executing "
1017 << "the program with the \"safe\" backend in this file for "
1019 << Result << "'.\n";
1024 DisambiguateGlobalSymbols(Program);
1026 std::vector<Function*> Funcs = DebugAMiscompilation(*this, TestCodeGenerator,
1028 if (!Error->empty())
1031 // Split the module into the two halves of the program we want.
1032 ValueToValueMapTy VMap;
1033 Module *ToNotCodeGen = CloneModule(getProgram(), VMap);
1034 Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs, VMap);
1036 // Condition the modules
1037 CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen);
1039 SmallString<128> TestModuleBC;
1041 std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
1042 TestModuleFD, TestModuleBC);
1044 errs() << getToolName() << "Error making unique filename: "
1045 << EC.message() << "\n";
1049 if (writeProgramToFile(TestModuleBC.str(), TestModuleFD, ToCodeGen)) {
1050 errs() << "Error writing bitcode to `" << TestModuleBC
1056 // Make the shared library
1057 SmallString<128> SafeModuleBC;
1059 EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD,
1062 errs() << getToolName() << "Error making unique filename: "
1063 << EC.message() << "\n";
1067 if (writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, ToNotCodeGen)) {
1068 errs() << "Error writing bitcode to `" << SafeModuleBC
1072 std::string SharedObject = compileSharedObject(SafeModuleBC.str(), *Error);
1073 if (!Error->empty())
1075 delete ToNotCodeGen;
1077 outs() << "You can reproduce the problem with the command line: \n";
1078 if (isExecutingJIT()) {
1079 outs() << " lli -load " << SharedObject << " " << TestModuleBC;
1081 outs() << " llc " << TestModuleBC << " -o " << TestModuleBC
1083 outs() << " gcc " << SharedObject << " " << TestModuleBC.str()
1084 << ".s -o " << TestModuleBC << ".exe";
1085 #if defined (HAVE_LINK_R)
1086 outs() << " -Wl,-R.";
1089 outs() << " " << TestModuleBC << ".exe";
1091 for (unsigned i = 0, e = InputArgv.size(); i != e; ++i)
1092 outs() << " " << InputArgv[i];
1094 outs() << "The shared object was created with:\n llc -march=c "
1095 << SafeModuleBC.str() << " -o temporary.c\n"
1096 << " gcc -xc temporary.c -O2 -o " << SharedObject;
1097 if (TargetTriple.getArch() == Triple::sparc)
1098 outs() << " -G"; // Compile a shared library, `-G' for Sparc
1100 outs() << " -fPIC -shared"; // `-shared' for Linux/X86, maybe others
1102 outs() << " -fno-strict-aliasing\n";