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"
30 using std::error_code;
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 /// TestMergedProgram - Given two modules, link them together and run the
212 /// program, checking to see if the program matches the diff. If there is
213 /// an error, return NULL. If not, return the merged module. The Broken argument
214 /// will be set to true if the output is different. If the DeleteInputs
215 /// argument is set to true then this function deletes both input
216 /// modules before it returns.
218 static Module *TestMergedProgram(const BugDriver &BD, Module *M1, Module *M2,
219 bool DeleteInputs, std::string &Error,
221 // Link the two portions of the program back to together.
222 std::string ErrorMsg;
224 M1 = CloneModule(M1);
225 M2 = CloneModule(M2);
227 if (Linker::LinkModules(M1, M2, Linker::DestroySource, &ErrorMsg)) {
228 errs() << BD.getToolName() << ": Error linking modules together:"
232 delete M2; // We are done with this module.
234 // Execute the program.
235 Broken = BD.diffProgram(M1, "", "", false, &Error);
236 if (!Error.empty()) {
237 // Delete the linked module
244 /// TestFuncs - split functions in a Module into two groups: those that are
245 /// under consideration for miscompilation vs. those that are not, and test
246 /// accordingly. Each group of functions becomes a separate Module.
248 bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs,
249 std::string &Error) {
250 // Test to see if the function is misoptimized if we ONLY run it on the
251 // functions listed in Funcs.
252 outs() << "Checking to see if the program is misoptimized when "
253 << (Funcs.size()==1 ? "this function is" : "these functions are")
254 << " run through the pass"
255 << (BD.getPassesToRun().size() == 1 ? "" : "es") << ":";
256 PrintFunctionList(Funcs);
259 // Create a clone for two reasons:
260 // * If the optimization passes delete any function, the deleted function
261 // will be in the clone and Funcs will still point to valid memory
262 // * If the optimization passes use interprocedural information to break
263 // a function, we want to continue with the original function. Otherwise
264 // we can conclude that a function triggers the bug when in fact one
265 // needs a larger set of original functions to do so.
266 ValueToValueMapTy VMap;
267 Module *Clone = CloneModule(BD.getProgram(), VMap);
268 Module *Orig = BD.swapProgramIn(Clone);
270 std::vector<Function*> FuncsOnClone;
271 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
272 Function *F = cast<Function>(VMap[Funcs[i]]);
273 FuncsOnClone.push_back(F);
276 // Split the module into the two halves of the program we want.
278 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
279 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, FuncsOnClone,
282 // Run the predicate, note that the predicate will delete both input modules.
283 bool Broken = TestFn(BD, ToOptimize, ToNotOptimize, Error);
285 delete BD.swapProgramIn(Orig);
290 /// DisambiguateGlobalSymbols - Give anonymous global values names.
292 static void DisambiguateGlobalSymbols(Module *M) {
293 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
296 I->setName("anon_global");
297 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
299 I->setName("anon_fn");
302 /// ExtractLoops - Given a reduced list of functions that still exposed the bug,
303 /// check to see if we can extract the loops in the region without obscuring the
304 /// bug. If so, it reduces the amount of code identified.
306 static bool ExtractLoops(BugDriver &BD,
307 bool (*TestFn)(BugDriver &, Module *, Module *,
309 std::vector<Function*> &MiscompiledFunctions,
310 std::string &Error) {
311 bool MadeChange = false;
313 if (BugpointIsInterrupted) return MadeChange;
315 ValueToValueMapTy VMap;
316 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
317 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
318 MiscompiledFunctions,
320 Module *ToOptimizeLoopExtracted = BD.ExtractLoop(ToOptimize);
321 if (!ToOptimizeLoopExtracted) {
322 // If the loop extractor crashed or if there were no extractible loops,
323 // then this chapter of our odyssey is over with.
324 delete ToNotOptimize;
329 errs() << "Extracted a loop from the breaking portion of the program.\n";
331 // Bugpoint is intentionally not very trusting of LLVM transformations. In
332 // particular, we're not going to assume that the loop extractor works, so
333 // we're going to test the newly loop extracted program to make sure nothing
334 // has broken. If something broke, then we'll inform the user and stop
336 AbstractInterpreter *AI = BD.switchToSafeInterpreter();
338 Module *New = TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize,
339 false, Error, Failure);
343 // Delete the original and set the new program.
344 Module *Old = BD.swapProgramIn(New);
345 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
346 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
350 BD.switchToInterpreter(AI);
352 // Merged program doesn't work anymore!
353 errs() << " *** ERROR: Loop extraction broke the program. :("
354 << " Please report a bug!\n";
355 errs() << " Continuing on with un-loop-extracted version.\n";
357 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-tno.bc",
359 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to.bc",
361 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to-le.bc",
362 ToOptimizeLoopExtracted);
364 errs() << "Please submit the "
365 << OutputPrefix << "-loop-extract-fail-*.bc files.\n";
367 delete ToNotOptimize;
368 delete ToOptimizeLoopExtracted;
372 BD.switchToInterpreter(AI);
374 outs() << " Testing after loop extraction:\n";
375 // Clone modules, the tester function will free them.
376 Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted, VMap);
377 Module *TNOBackup = CloneModule(ToNotOptimize, VMap);
379 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
380 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
382 Failure = TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize, Error);
386 ToOptimizeLoopExtracted = TOLEBackup;
387 ToNotOptimize = TNOBackup;
390 outs() << "*** Loop extraction masked the problem. Undoing.\n";
391 // If the program is not still broken, then loop extraction did something
392 // that masked the error. Stop loop extraction now.
394 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
395 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) {
396 Function *F = MiscompiledFunctions[i];
397 MisCompFunctions.push_back(std::make_pair(F->getName(),
398 F->getFunctionType()));
401 std::string ErrorMsg;
402 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted,
403 Linker::DestroySource, &ErrorMsg)){
404 errs() << BD.getToolName() << ": Error linking modules together:"
409 MiscompiledFunctions.clear();
410 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
411 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
413 assert(NewF && "Function not found??");
414 MiscompiledFunctions.push_back(NewF);
417 delete ToOptimizeLoopExtracted;
418 BD.setNewProgram(ToNotOptimize);
422 outs() << "*** Loop extraction successful!\n";
424 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
425 for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
426 E = ToOptimizeLoopExtracted->end(); I != E; ++I)
427 if (!I->isDeclaration())
428 MisCompFunctions.push_back(std::make_pair(I->getName(),
429 I->getFunctionType()));
431 // Okay, great! Now we know that we extracted a loop and that loop
432 // extraction both didn't break the program, and didn't mask the problem.
433 // Replace the current program with the loop extracted version, and try to
434 // extract another loop.
435 std::string ErrorMsg;
436 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted,
437 Linker::DestroySource, &ErrorMsg)){
438 errs() << BD.getToolName() << ": Error linking modules together:"
442 delete ToOptimizeLoopExtracted;
444 // All of the Function*'s in the MiscompiledFunctions list are in the old
445 // module. Update this list to include all of the functions in the
446 // optimized and loop extracted module.
447 MiscompiledFunctions.clear();
448 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
449 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
451 assert(NewF && "Function not found??");
452 MiscompiledFunctions.push_back(NewF);
455 BD.setNewProgram(ToNotOptimize);
461 class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> {
463 bool (*TestFn)(BugDriver &, Module *, Module *, std::string &);
464 std::vector<Function*> FunctionsBeingTested;
466 ReduceMiscompiledBlocks(BugDriver &bd,
467 bool (*F)(BugDriver &, Module *, Module *,
469 const std::vector<Function*> &Fns)
470 : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {}
472 TestResult doTest(std::vector<BasicBlock*> &Prefix,
473 std::vector<BasicBlock*> &Suffix,
474 std::string &Error) override {
475 if (!Suffix.empty()) {
476 bool Ret = TestFuncs(Suffix, Error);
478 return InternalError;
482 if (!Prefix.empty()) {
483 bool Ret = TestFuncs(Prefix, Error);
485 return InternalError;
492 bool TestFuncs(const std::vector<BasicBlock*> &BBs, std::string &Error);
496 /// TestFuncs - Extract all blocks for the miscompiled functions except for the
497 /// specified blocks. If the problem still exists, return true.
499 bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs,
500 std::string &Error) {
501 // Test to see if the function is misoptimized if we ONLY run it on the
502 // functions listed in Funcs.
503 outs() << "Checking to see if the program is misoptimized when all ";
505 outs() << "but these " << BBs.size() << " blocks are extracted: ";
506 for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i)
507 outs() << BBs[i]->getName() << " ";
508 if (BBs.size() > 10) outs() << "...";
510 outs() << "blocks are extracted.";
514 // Split the module into the two halves of the program we want.
515 ValueToValueMapTy VMap;
516 Module *Clone = CloneModule(BD.getProgram(), VMap);
517 Module *Orig = BD.swapProgramIn(Clone);
518 std::vector<Function*> FuncsOnClone;
519 std::vector<BasicBlock*> BBsOnClone;
520 for (unsigned i = 0, e = FunctionsBeingTested.size(); i != e; ++i) {
521 Function *F = cast<Function>(VMap[FunctionsBeingTested[i]]);
522 FuncsOnClone.push_back(F);
524 for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
525 BasicBlock *BB = cast<BasicBlock>(VMap[BBs[i]]);
526 BBsOnClone.push_back(BB);
530 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
531 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
535 // Try the extraction. If it doesn't work, then the block extractor crashed
536 // or something, in which case bugpoint can't chase down this possibility.
537 if (Module *New = BD.ExtractMappedBlocksFromModule(BBsOnClone, ToOptimize)) {
539 // Run the predicate,
540 // note that the predicate will delete both input modules.
541 bool Ret = TestFn(BD, New, ToNotOptimize, Error);
542 delete BD.swapProgramIn(Orig);
545 delete BD.swapProgramIn(Orig);
547 delete ToNotOptimize;
552 /// ExtractBlocks - Given a reduced list of functions that still expose the bug,
553 /// extract as many basic blocks from the region as possible without obscuring
556 static bool ExtractBlocks(BugDriver &BD,
557 bool (*TestFn)(BugDriver &, Module *, Module *,
559 std::vector<Function*> &MiscompiledFunctions,
560 std::string &Error) {
561 if (BugpointIsInterrupted) return false;
563 std::vector<BasicBlock*> Blocks;
564 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
565 for (Function::iterator I = MiscompiledFunctions[i]->begin(),
566 E = MiscompiledFunctions[i]->end(); I != E; ++I)
569 // Use the list reducer to identify blocks that can be extracted without
570 // obscuring the bug. The Blocks list will end up containing blocks that must
571 // be retained from the original program.
572 unsigned OldSize = Blocks.size();
574 // Check to see if all blocks are extractible first.
575 bool Ret = ReduceMiscompiledBlocks(BD, TestFn, MiscompiledFunctions)
576 .TestFuncs(std::vector<BasicBlock*>(), Error);
582 ReduceMiscompiledBlocks(BD, TestFn,
583 MiscompiledFunctions).reduceList(Blocks, Error);
586 if (Blocks.size() == OldSize)
590 ValueToValueMapTy VMap;
591 Module *ProgClone = CloneModule(BD.getProgram(), VMap);
592 Module *ToExtract = SplitFunctionsOutOfModule(ProgClone,
593 MiscompiledFunctions,
595 Module *Extracted = 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, Linker::DestroySource,
618 errs() << BD.getToolName() << ": Error linking modules together:"
624 // Set the new program and delete the old one.
625 BD.setNewProgram(ProgClone);
627 // Update the list of miscompiled functions.
628 MiscompiledFunctions.clear();
630 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
631 Function *NewF = ProgClone->getFunction(MisCompFunctions[i].first);
632 assert(NewF && "Function not found??");
633 MiscompiledFunctions.push_back(NewF);
640 /// DebugAMiscompilation - This is a generic driver to narrow down
641 /// miscompilations, either in an optimization or a code generator.
643 static std::vector<Function*>
644 DebugAMiscompilation(BugDriver &BD,
645 bool (*TestFn)(BugDriver &, Module *, Module *,
647 std::string &Error) {
648 // Okay, now that we have reduced the list of passes which are causing the
649 // failure, see if we can pin down which functions are being
650 // miscompiled... first build a list of all of the non-external functions in
652 std::vector<Function*> MiscompiledFunctions;
653 Module *Prog = BD.getProgram();
654 for (Module::iterator I = Prog->begin(), E = Prog->end(); I != E; ++I)
655 if (!I->isDeclaration())
656 MiscompiledFunctions.push_back(I);
658 // Do the reduction...
659 if (!BugpointIsInterrupted)
660 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
662 if (!Error.empty()) {
663 errs() << "\n***Cannot reduce functions: ";
664 return MiscompiledFunctions;
666 outs() << "\n*** The following function"
667 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
668 << " being miscompiled: ";
669 PrintFunctionList(MiscompiledFunctions);
672 // See if we can rip any loops out of the miscompiled functions and still
673 // trigger the problem.
675 if (!BugpointIsInterrupted && !DisableLoopExtraction) {
676 bool Ret = ExtractLoops(BD, TestFn, MiscompiledFunctions, Error);
678 return MiscompiledFunctions;
680 // Okay, we extracted some loops and the problem still appears. See if
681 // we can eliminate some of the created functions from being candidates.
682 DisambiguateGlobalSymbols(BD.getProgram());
684 // Do the reduction...
685 if (!BugpointIsInterrupted)
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 if (!BugpointIsInterrupted && !DisableBlockExtraction) {
700 bool Ret = ExtractBlocks(BD, TestFn, MiscompiledFunctions, Error);
702 return MiscompiledFunctions;
704 // Okay, we extracted some blocks and the problem still appears. See if
705 // we can eliminate some of the created functions from being candidates.
706 DisambiguateGlobalSymbols(BD.getProgram());
708 // Do the reduction...
709 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
712 return MiscompiledFunctions;
714 outs() << "\n*** The following function"
715 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
716 << " being miscompiled: ";
717 PrintFunctionList(MiscompiledFunctions);
722 return MiscompiledFunctions;
725 /// TestOptimizer - This is the predicate function used to check to see if the
726 /// "Test" portion of the program is misoptimized. If so, return true. In any
727 /// case, both module arguments are deleted.
729 static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe,
730 std::string &Error) {
731 // Run the optimization passes on ToOptimize, producing a transformed version
732 // of the functions being tested.
733 outs() << " Optimizing functions being tested: ";
734 Module *Optimized = BD.runPassesOn(Test, BD.getPassesToRun(),
735 /*AutoDebugCrashes*/true);
739 outs() << " Checking to see if the merged program executes correctly: ";
741 Module *New = TestMergedProgram(BD, Optimized, 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);
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 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 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";