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/Constants.h"
19 #include "llvm/DerivedTypes.h"
20 #include "llvm/Instructions.h"
21 #include "llvm/Linker.h"
22 #include "llvm/Module.h"
23 #include "llvm/Pass.h"
24 #include "llvm/Analysis/Verifier.h"
25 #include "llvm/Transforms/Utils/Cloning.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Support/FileUtilities.h"
28 #include "llvm/Config/config.h" // for HAVE_LINK_R
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<const PassInfo*> {
49 ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
51 virtual TestResult doTest(std::vector<const PassInfo*> &Prefix,
52 std::vector<const PassInfo*> &Suffix);
56 /// TestResult - After passes have been split into a test group and a control
57 /// group, see if they still break the program.
59 ReduceMiscompilingPasses::TestResult
60 ReduceMiscompilingPasses::doTest(std::vector<const PassInfo*> &Prefix,
61 std::vector<const PassInfo*> &Suffix) {
62 // First, run the program with just the Suffix passes. If it is still broken
63 // with JUST the kept passes, discard the prefix passes.
64 outs() << "Checking to see if '" << getPassesString(Suffix)
65 << "' compiles correctly: ";
67 std::string BitcodeResult;
68 if (BD.runPasses(Suffix, BitcodeResult, false/*delete*/, true/*quiet*/)) {
69 errs() << " Error running this sequence of passes"
70 << " on the input program!\n";
71 BD.setPassesToRun(Suffix);
72 BD.EmitProgressBitcode("pass-error", false);
73 exit(BD.debugOptimizerCrash());
76 // Check to see if the finished program matches the reference output...
77 if (BD.diffProgram(BitcodeResult, "", true /*delete bitcode*/)) {
80 errs() << BD.getToolName() << ": I'm confused: the test fails when "
81 << "no passes are run, nondeterministic program?\n";
84 return KeepSuffix; // Miscompilation detected!
86 outs() << " yup.\n"; // No miscompilation!
88 if (Prefix.empty()) return NoFailure;
90 // Next, see if the program is broken if we run the "prefix" passes first,
91 // then separately run the "kept" passes.
92 outs() << "Checking to see if '" << getPassesString(Prefix)
93 << "' compiles correctly: ";
95 // If it is not broken with the kept passes, it's possible that the prefix
96 // passes must be run before the kept passes to break it. If the program
97 // WORKS after the prefix passes, but then fails if running the prefix AND
98 // kept passes, we can update our bitcode file to include the result of the
99 // prefix passes, then discard the prefix passes.
101 if (BD.runPasses(Prefix, BitcodeResult, false/*delete*/, true/*quiet*/)) {
102 errs() << " Error running this sequence of passes"
103 << " on the input program!\n";
104 BD.setPassesToRun(Prefix);
105 BD.EmitProgressBitcode("pass-error", false);
106 exit(BD.debugOptimizerCrash());
109 // If the prefix maintains the predicate by itself, only keep the prefix!
110 if (BD.diffProgram(BitcodeResult)) {
111 outs() << " nope.\n";
112 sys::Path(BitcodeResult).eraseFromDisk();
115 outs() << " yup.\n"; // No miscompilation!
117 // Ok, so now we know that the prefix passes work, try running the suffix
118 // passes on the result of the prefix passes.
120 Module *PrefixOutput = ParseInputFile(BitcodeResult, BD.getContext());
121 if (PrefixOutput == 0) {
122 errs() << BD.getToolName() << ": Error reading bitcode file '"
123 << BitcodeResult << "'!\n";
126 sys::Path(BitcodeResult).eraseFromDisk(); // No longer need the file on disk
128 // Don't check if there are no passes in the suffix.
132 outs() << "Checking to see if '" << getPassesString(Suffix)
133 << "' passes compile correctly after the '"
134 << getPassesString(Prefix) << "' passes: ";
136 Module *OriginalInput = BD.swapProgramIn(PrefixOutput);
137 if (BD.runPasses(Suffix, BitcodeResult, false/*delete*/, true/*quiet*/)) {
138 errs() << " Error running this sequence of passes"
139 << " on the input program!\n";
140 BD.setPassesToRun(Suffix);
141 BD.EmitProgressBitcode("pass-error", false);
142 exit(BD.debugOptimizerCrash());
146 if (BD.diffProgram(BitcodeResult, "", true/*delete bitcode*/)) {
147 outs() << " nope.\n";
148 delete OriginalInput; // We pruned down the original input...
152 // Otherwise, we must not be running the bad pass anymore.
153 outs() << " yup.\n"; // No miscompilation!
154 delete BD.swapProgramIn(OriginalInput); // Restore orig program & free test
159 class ReduceMiscompilingFunctions : public ListReducer<Function*> {
161 bool (*TestFn)(BugDriver &, Module *, Module *);
163 ReduceMiscompilingFunctions(BugDriver &bd,
164 bool (*F)(BugDriver &, Module *, Module *))
165 : BD(bd), TestFn(F) {}
167 virtual TestResult doTest(std::vector<Function*> &Prefix,
168 std::vector<Function*> &Suffix) {
169 if (!Suffix.empty() && TestFuncs(Suffix))
171 if (!Prefix.empty() && TestFuncs(Prefix))
176 bool TestFuncs(const std::vector<Function*> &Prefix);
180 /// TestMergedProgram - Given two modules, link them together and run the
181 /// program, checking to see if the program matches the diff. If the diff
182 /// matches, return false, otherwise return true. If the DeleteInputs argument
183 /// is set to true then this function deletes both input modules before it
186 static bool TestMergedProgram(BugDriver &BD, Module *M1, Module *M2,
188 // Link the two portions of the program back to together.
189 std::string ErrorMsg;
191 M1 = CloneModule(M1);
192 M2 = CloneModule(M2);
194 if (Linker::LinkModules(M1, M2, &ErrorMsg)) {
195 errs() << BD.getToolName() << ": Error linking modules together:"
199 delete M2; // We are done with this module.
201 Module *OldProgram = BD.swapProgramIn(M1);
203 // Execute the program. If it does not match the expected output, we must
205 bool Broken = BD.diffProgram();
207 // Delete the linked module & restore the original
208 BD.swapProgramIn(OldProgram);
213 /// TestFuncs - split functions in a Module into two groups: those that are
214 /// under consideration for miscompilation vs. those that are not, and test
215 /// accordingly. Each group of functions becomes a separate Module.
217 bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*>&Funcs){
218 // Test to see if the function is misoptimized if we ONLY run it on the
219 // functions listed in Funcs.
220 outs() << "Checking to see if the program is misoptimized when "
221 << (Funcs.size()==1 ? "this function is" : "these functions are")
222 << " run through the pass"
223 << (BD.getPassesToRun().size() == 1 ? "" : "es") << ":";
224 PrintFunctionList(Funcs);
227 // Split the module into the two halves of the program we want.
228 DenseMap<const Value*, Value*> ValueMap;
229 Module *ToNotOptimize = CloneModule(BD.getProgram(), ValueMap);
230 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, Funcs,
233 // Run the predicate, note that the predicate will delete both input modules.
234 return TestFn(BD, ToOptimize, ToNotOptimize);
237 /// DisambiguateGlobalSymbols - Give anonymous global values names.
239 static void DisambiguateGlobalSymbols(Module *M) {
240 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
242 // Don't mangle asm names.
244 I->setName("anon_global");
246 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) {
248 I->setName("anon_fn");
252 /// ExtractLoops - Given a reduced list of functions that still exposed the bug,
253 /// check to see if we can extract the loops in the region without obscuring the
254 /// bug. If so, it reduces the amount of code identified.
256 static bool ExtractLoops(BugDriver &BD,
257 bool (*TestFn)(BugDriver &, Module *, Module *),
258 std::vector<Function*> &MiscompiledFunctions) {
259 bool MadeChange = false;
261 if (BugpointIsInterrupted) return MadeChange;
263 DenseMap<const Value*, Value*> ValueMap;
264 Module *ToNotOptimize = CloneModule(BD.getProgram(), ValueMap);
265 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
266 MiscompiledFunctions,
268 Module *ToOptimizeLoopExtracted = BD.ExtractLoop(ToOptimize);
269 if (!ToOptimizeLoopExtracted) {
270 // If the loop extractor crashed or if there were no extractible loops,
271 // then this chapter of our odyssey is over with.
272 delete ToNotOptimize;
277 errs() << "Extracted a loop from the breaking portion of the program.\n";
279 // Bugpoint is intentionally not very trusting of LLVM transformations. In
280 // particular, we're not going to assume that the loop extractor works, so
281 // we're going to test the newly loop extracted program to make sure nothing
282 // has broken. If something broke, then we'll inform the user and stop
284 AbstractInterpreter *AI = BD.switchToSafeInterpreter();
285 if (TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize, false)) {
286 BD.switchToInterpreter(AI);
288 // Merged program doesn't work anymore!
289 errs() << " *** ERROR: Loop extraction broke the program. :("
290 << " Please report a bug!\n";
291 errs() << " Continuing on with un-loop-extracted version.\n";
293 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-tno.bc",
295 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to.bc",
297 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to-le.bc",
298 ToOptimizeLoopExtracted);
300 errs() << "Please submit the "
301 << OutputPrefix << "-loop-extract-fail-*.bc files.\n";
303 delete ToNotOptimize;
304 delete ToOptimizeLoopExtracted;
308 BD.switchToInterpreter(AI);
310 outs() << " Testing after loop extraction:\n";
311 // Clone modules, the tester function will free them.
312 Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted);
313 Module *TNOBackup = CloneModule(ToNotOptimize);
314 if (!TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize)) {
315 outs() << "*** Loop extraction masked the problem. Undoing.\n";
316 // If the program is not still broken, then loop extraction did something
317 // that masked the error. Stop loop extraction now.
322 ToOptimizeLoopExtracted = TOLEBackup;
323 ToNotOptimize = TNOBackup;
325 outs() << "*** Loop extraction successful!\n";
327 std::vector<std::pair<std::string, const FunctionType*> > MisCompFunctions;
328 for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
329 E = ToOptimizeLoopExtracted->end(); I != E; ++I)
330 if (!I->isDeclaration())
331 MisCompFunctions.push_back(std::make_pair(I->getName(),
332 I->getFunctionType()));
334 // Okay, great! Now we know that we extracted a loop and that loop
335 // extraction both didn't break the program, and didn't mask the problem.
336 // Replace the current program with the loop extracted version, and try to
337 // extract another loop.
338 std::string ErrorMsg;
339 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted, &ErrorMsg)){
340 errs() << BD.getToolName() << ": Error linking modules together:"
344 delete ToOptimizeLoopExtracted;
346 // All of the Function*'s in the MiscompiledFunctions list are in the old
347 // module. Update this list to include all of the functions in the
348 // optimized and loop extracted module.
349 MiscompiledFunctions.clear();
350 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
351 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
353 assert(NewF && "Function not found??");
354 assert(NewF->getFunctionType() == MisCompFunctions[i].second &&
355 "found wrong function type?");
356 MiscompiledFunctions.push_back(NewF);
359 BD.setNewProgram(ToNotOptimize);
365 class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> {
367 bool (*TestFn)(BugDriver &, Module *, Module *);
368 std::vector<Function*> FunctionsBeingTested;
370 ReduceMiscompiledBlocks(BugDriver &bd,
371 bool (*F)(BugDriver &, Module *, Module *),
372 const std::vector<Function*> &Fns)
373 : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {}
375 virtual TestResult doTest(std::vector<BasicBlock*> &Prefix,
376 std::vector<BasicBlock*> &Suffix) {
377 if (!Suffix.empty() && TestFuncs(Suffix))
379 if (TestFuncs(Prefix))
384 bool TestFuncs(const std::vector<BasicBlock*> &Prefix);
388 /// TestFuncs - Extract all blocks for the miscompiled functions except for the
389 /// specified blocks. If the problem still exists, return true.
391 bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs) {
392 // Test to see if the function is misoptimized if we ONLY run it on the
393 // functions listed in Funcs.
394 outs() << "Checking to see if the program is misoptimized when all ";
396 outs() << "but these " << BBs.size() << " blocks are extracted: ";
397 for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i)
398 outs() << BBs[i]->getName() << " ";
399 if (BBs.size() > 10) outs() << "...";
401 outs() << "blocks are extracted.";
405 // Split the module into the two halves of the program we want.
406 DenseMap<const Value*, Value*> ValueMap;
407 Module *ToNotOptimize = CloneModule(BD.getProgram(), ValueMap);
408 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
409 FunctionsBeingTested,
412 // Try the extraction. If it doesn't work, then the block extractor crashed
413 // or something, in which case bugpoint can't chase down this possibility.
414 if (Module *New = BD.ExtractMappedBlocksFromModule(BBs, ToOptimize)) {
416 // Run the predicate, not that the predicate will delete both input modules.
417 return TestFn(BD, New, ToNotOptimize);
420 delete ToNotOptimize;
425 /// ExtractBlocks - Given a reduced list of functions that still expose the bug,
426 /// extract as many basic blocks from the region as possible without obscuring
429 static bool ExtractBlocks(BugDriver &BD,
430 bool (*TestFn)(BugDriver &, Module *, Module *),
431 std::vector<Function*> &MiscompiledFunctions) {
432 if (BugpointIsInterrupted) return false;
434 std::vector<BasicBlock*> Blocks;
435 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
436 for (Function::iterator I = MiscompiledFunctions[i]->begin(),
437 E = MiscompiledFunctions[i]->end(); I != E; ++I)
440 // Use the list reducer to identify blocks that can be extracted without
441 // obscuring the bug. The Blocks list will end up containing blocks that must
442 // be retained from the original program.
443 unsigned OldSize = Blocks.size();
445 // Check to see if all blocks are extractible first.
446 if (ReduceMiscompiledBlocks(BD, TestFn,
447 MiscompiledFunctions).TestFuncs(std::vector<BasicBlock*>())) {
450 ReduceMiscompiledBlocks(BD, TestFn,MiscompiledFunctions).reduceList(Blocks);
451 if (Blocks.size() == OldSize)
455 DenseMap<const Value*, Value*> ValueMap;
456 Module *ProgClone = CloneModule(BD.getProgram(), ValueMap);
457 Module *ToExtract = SplitFunctionsOutOfModule(ProgClone,
458 MiscompiledFunctions,
460 Module *Extracted = BD.ExtractMappedBlocksFromModule(Blocks, ToExtract);
461 if (Extracted == 0) {
462 // Weird, extraction should have worked.
463 errs() << "Nondeterministic problem extracting blocks??\n";
469 // Otherwise, block extraction succeeded. Link the two program fragments back
473 std::vector<std::pair<std::string, const FunctionType*> > MisCompFunctions;
474 for (Module::iterator I = Extracted->begin(), E = Extracted->end();
476 if (!I->isDeclaration())
477 MisCompFunctions.push_back(std::make_pair(I->getName(),
478 I->getFunctionType()));
480 std::string ErrorMsg;
481 if (Linker::LinkModules(ProgClone, Extracted, &ErrorMsg)) {
482 errs() << BD.getToolName() << ": Error linking modules together:"
488 // Set the new program and delete the old one.
489 BD.setNewProgram(ProgClone);
491 // Update the list of miscompiled functions.
492 MiscompiledFunctions.clear();
494 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
495 Function *NewF = ProgClone->getFunction(MisCompFunctions[i].first);
496 assert(NewF && "Function not found??");
497 assert(NewF->getFunctionType() == MisCompFunctions[i].second &&
498 "Function has wrong type??");
499 MiscompiledFunctions.push_back(NewF);
506 /// DebugAMiscompilation - This is a generic driver to narrow down
507 /// miscompilations, either in an optimization or a code generator.
509 static std::vector<Function*>
510 DebugAMiscompilation(BugDriver &BD,
511 bool (*TestFn)(BugDriver &, Module *, Module *)) {
512 // Okay, now that we have reduced the list of passes which are causing the
513 // failure, see if we can pin down which functions are being
514 // miscompiled... first build a list of all of the non-external functions in
516 std::vector<Function*> MiscompiledFunctions;
517 Module *Prog = BD.getProgram();
518 for (Module::iterator I = Prog->begin(), E = Prog->end(); I != E; ++I)
519 if (!I->isDeclaration())
520 MiscompiledFunctions.push_back(I);
522 // Do the reduction...
523 if (!BugpointIsInterrupted)
524 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
526 outs() << "\n*** The following function"
527 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
528 << " being miscompiled: ";
529 PrintFunctionList(MiscompiledFunctions);
532 // See if we can rip any loops out of the miscompiled functions and still
533 // trigger the problem.
535 if (!BugpointIsInterrupted && !DisableLoopExtraction &&
536 ExtractLoops(BD, TestFn, MiscompiledFunctions)) {
537 // Okay, we extracted some loops and the problem still appears. See if we
538 // can eliminate some of the created functions from being candidates.
539 DisambiguateGlobalSymbols(BD.getProgram());
541 // Do the reduction...
542 if (!BugpointIsInterrupted)
543 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
545 outs() << "\n*** The following function"
546 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
547 << " being miscompiled: ";
548 PrintFunctionList(MiscompiledFunctions);
552 if (!BugpointIsInterrupted && !DisableBlockExtraction &&
553 ExtractBlocks(BD, TestFn, MiscompiledFunctions)) {
554 // Okay, we extracted some blocks and the problem still appears. See if we
555 // can eliminate some of the created functions from being candidates.
556 DisambiguateGlobalSymbols(BD.getProgram());
558 // Do the reduction...
559 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
561 outs() << "\n*** The following function"
562 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
563 << " being miscompiled: ";
564 PrintFunctionList(MiscompiledFunctions);
568 return MiscompiledFunctions;
571 /// TestOptimizer - This is the predicate function used to check to see if the
572 /// "Test" portion of the program is misoptimized. If so, return true. In any
573 /// case, both module arguments are deleted.
575 static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe) {
576 // Run the optimization passes on ToOptimize, producing a transformed version
577 // of the functions being tested.
578 outs() << " Optimizing functions being tested: ";
579 Module *Optimized = BD.runPassesOn(Test, BD.getPassesToRun(),
580 /*AutoDebugCrashes*/true);
584 outs() << " Checking to see if the merged program executes correctly: ";
585 bool Broken = TestMergedProgram(BD, Optimized, Safe, true);
586 outs() << (Broken ? " nope.\n" : " yup.\n");
591 /// debugMiscompilation - This method is used when the passes selected are not
592 /// crashing, but the generated output is semantically different from the
595 bool BugDriver::debugMiscompilation() {
596 // Make sure something was miscompiled...
597 if (!BugpointIsInterrupted)
598 if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun)) {
599 errs() << "*** Optimized program matches reference output! No problem"
600 << " detected...\nbugpoint can't help you with your problem!\n";
604 outs() << "\n*** Found miscompiling pass"
605 << (getPassesToRun().size() == 1 ? "" : "es") << ": "
606 << getPassesString(getPassesToRun()) << '\n';
607 EmitProgressBitcode("passinput");
609 std::vector<Function*> MiscompiledFunctions =
610 DebugAMiscompilation(*this, TestOptimizer);
612 // Output a bunch of bitcode files for the user...
613 outs() << "Outputting reduced bitcode files which expose the problem:\n";
614 DenseMap<const Value*, Value*> ValueMap;
615 Module *ToNotOptimize = CloneModule(getProgram(), ValueMap);
616 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
617 MiscompiledFunctions,
620 outs() << " Non-optimized portion: ";
621 ToNotOptimize = swapProgramIn(ToNotOptimize);
622 EmitProgressBitcode("tonotoptimize", true);
623 setNewProgram(ToNotOptimize); // Delete hacked module.
625 outs() << " Portion that is input to optimizer: ";
626 ToOptimize = swapProgramIn(ToOptimize);
627 EmitProgressBitcode("tooptimize");
628 setNewProgram(ToOptimize); // Delete hacked module.
633 /// CleanupAndPrepareModules - Get the specified modules ready for code
634 /// generator testing.
636 static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
638 // Clean up the modules, removing extra cruft that we don't need anymore...
639 Test = BD.performFinalCleanups(Test);
641 // If we are executing the JIT, we have several nasty issues to take care of.
642 if (!BD.isExecutingJIT()) return;
644 // First, if the main function is in the Safe module, we must add a stub to
645 // the Test module to call into it. Thus, we create a new function `main'
646 // which just calls the old one.
647 if (Function *oldMain = Safe->getFunction("main"))
648 if (!oldMain->isDeclaration()) {
650 oldMain->setName("llvm_bugpoint_old_main");
651 // Create a NEW `main' function with same type in the test module.
652 Function *newMain = Function::Create(oldMain->getFunctionType(),
653 GlobalValue::ExternalLinkage,
655 // Create an `oldmain' prototype in the test module, which will
656 // corresponds to the real main function in the same module.
657 Function *oldMainProto = Function::Create(oldMain->getFunctionType(),
658 GlobalValue::ExternalLinkage,
659 oldMain->getName(), Test);
660 // Set up and remember the argument list for the main function.
661 std::vector<Value*> args;
662 for (Function::arg_iterator
663 I = newMain->arg_begin(), E = newMain->arg_end(),
664 OI = oldMain->arg_begin(); I != E; ++I, ++OI) {
665 I->setName(OI->getName()); // Copy argument names from oldMain
669 // Call the old main function and return its result
670 BasicBlock *BB = BasicBlock::Create(Safe->getContext(), "entry", newMain);
671 CallInst *call = CallInst::Create(oldMainProto, args.begin(), args.end(),
674 // If the type of old function wasn't void, return value of call
675 ReturnInst::Create(Safe->getContext(), call, BB);
678 // The second nasty issue we must deal with in the JIT is that the Safe
679 // module cannot directly reference any functions defined in the test
680 // module. Instead, we use a JIT API call to dynamically resolve the
683 // Add the resolver to the Safe module.
684 // Prototype: void *getPointerToNamedFunction(const char* Name)
685 Constant *resolverFunc =
686 Safe->getOrInsertFunction("getPointerToNamedFunction",
687 Type::getInt8PtrTy(Safe->getContext()),
688 Type::getInt8PtrTy(Safe->getContext()),
691 // Use the function we just added to get addresses of functions we need.
692 for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) {
693 if (F->isDeclaration() && !F->use_empty() && &*F != resolverFunc &&
694 !F->isIntrinsic() /* ignore intrinsics */) {
695 Function *TestFn = Test->getFunction(F->getName());
697 // Don't forward functions which are external in the test module too.
698 if (TestFn && !TestFn->isDeclaration()) {
699 // 1. Add a string constant with its name to the global file
700 Constant *InitArray = ConstantArray::get(F->getContext(), F->getName());
701 GlobalVariable *funcName =
702 new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/,
703 GlobalValue::InternalLinkage, InitArray,
704 F->getName() + "_name");
706 // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
707 // sbyte* so it matches the signature of the resolver function.
709 // GetElementPtr *funcName, ulong 0, ulong 0
710 std::vector<Constant*> GEPargs(2,
711 Constant::getNullValue(Type::getInt32Ty(F->getContext())));
713 ConstantExpr::getGetElementPtr(funcName, &GEPargs[0], 2);
714 std::vector<Value*> ResolverArgs;
715 ResolverArgs.push_back(GEP);
717 // Rewrite uses of F in global initializers, etc. to uses of a wrapper
718 // function that dynamically resolves the calls to F via our JIT API
719 if (!F->use_empty()) {
720 // Create a new global to hold the cached function pointer.
721 Constant *NullPtr = ConstantPointerNull::get(F->getType());
722 GlobalVariable *Cache =
723 new GlobalVariable(*F->getParent(), F->getType(),
724 false, GlobalValue::InternalLinkage,
725 NullPtr,F->getName()+".fpcache");
727 // Construct a new stub function that will re-route calls to F
728 const FunctionType *FuncTy = F->getFunctionType();
729 Function *FuncWrapper = Function::Create(FuncTy,
730 GlobalValue::InternalLinkage,
731 F->getName() + "_wrapper",
733 BasicBlock *EntryBB = BasicBlock::Create(F->getContext(),
734 "entry", FuncWrapper);
735 BasicBlock *DoCallBB = BasicBlock::Create(F->getContext(),
736 "usecache", FuncWrapper);
737 BasicBlock *LookupBB = BasicBlock::Create(F->getContext(),
738 "lookupfp", FuncWrapper);
740 // Check to see if we already looked up the value.
741 Value *CachedVal = new LoadInst(Cache, "fpcache", EntryBB);
742 Value *IsNull = new ICmpInst(*EntryBB, ICmpInst::ICMP_EQ, CachedVal,
744 BranchInst::Create(LookupBB, DoCallBB, IsNull, EntryBB);
746 // Resolve the call to function F via the JIT API:
748 // call resolver(GetElementPtr...)
750 CallInst::Create(resolverFunc, ResolverArgs.begin(),
751 ResolverArgs.end(), "resolver", LookupBB);
753 // Cast the result from the resolver to correctly-typed function.
754 CastInst *CastedResolver =
755 new BitCastInst(Resolver,
756 PointerType::getUnqual(F->getFunctionType()),
757 "resolverCast", LookupBB);
759 // Save the value in our cache.
760 new StoreInst(CastedResolver, Cache, LookupBB);
761 BranchInst::Create(DoCallBB, LookupBB);
763 PHINode *FuncPtr = PHINode::Create(NullPtr->getType(),
765 FuncPtr->addIncoming(CastedResolver, LookupBB);
766 FuncPtr->addIncoming(CachedVal, EntryBB);
768 // Save the argument list.
769 std::vector<Value*> Args;
770 for (Function::arg_iterator i = FuncWrapper->arg_begin(),
771 e = FuncWrapper->arg_end(); i != e; ++i)
774 // Pass on the arguments to the real function, return its result
775 if (F->getReturnType() == Type::getVoidTy(F->getContext())) {
776 CallInst::Create(FuncPtr, Args.begin(), Args.end(), "", DoCallBB);
777 ReturnInst::Create(F->getContext(), DoCallBB);
779 CallInst *Call = CallInst::Create(FuncPtr, Args.begin(), Args.end(),
781 ReturnInst::Create(F->getContext(),Call, DoCallBB);
784 // Use the wrapper function instead of the old function
785 F->replaceAllUsesWith(FuncWrapper);
791 if (verifyModule(*Test) || verifyModule(*Safe)) {
792 errs() << "Bugpoint has a bug, which corrupted a module!!\n";
799 /// TestCodeGenerator - This is the predicate function used to check to see if
800 /// the "Test" portion of the program is miscompiled by the code generator under
801 /// test. If so, return true. In any case, both module arguments are deleted.
803 static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe) {
804 CleanupAndPrepareModules(BD, Test, Safe);
806 sys::Path TestModuleBC("bugpoint.test.bc");
808 if (TestModuleBC.makeUnique(true, &ErrMsg)) {
809 errs() << BD.getToolName() << "Error making unique filename: "
813 if (BD.writeProgramToFile(TestModuleBC.str(), Test)) {
814 errs() << "Error writing bitcode to `" << TestModuleBC.str()
820 // Make the shared library
821 sys::Path SafeModuleBC("bugpoint.safe.bc");
822 if (SafeModuleBC.makeUnique(true, &ErrMsg)) {
823 errs() << BD.getToolName() << "Error making unique filename: "
828 if (BD.writeProgramToFile(SafeModuleBC.str(), Safe)) {
829 errs() << "Error writing bitcode to `" << SafeModuleBC.str()
833 std::string SharedObject = BD.compileSharedObject(SafeModuleBC.str());
836 // Run the code generator on the `Test' code, loading the shared library.
837 // The function returns whether or not the new output differs from reference.
838 int Result = BD.diffProgram(TestModuleBC.str(), SharedObject, false);
841 errs() << ": still failing!\n";
843 errs() << ": didn't fail.\n";
844 TestModuleBC.eraseFromDisk();
845 SafeModuleBC.eraseFromDisk();
846 sys::Path(SharedObject).eraseFromDisk();
852 /// debugCodeGenerator - debug errors in LLC, LLI, or CBE.
854 bool BugDriver::debugCodeGenerator() {
855 if ((void*)SafeInterpreter == (void*)Interpreter) {
856 std::string Result = executeProgramSafely("bugpoint.safe.out");
857 outs() << "\n*** The \"safe\" i.e. 'known good' backend cannot match "
858 << "the reference diff. This may be due to a\n front-end "
859 << "bug or a bug in the original program, but this can also "
860 << "happen if bugpoint isn't running the program with the "
861 << "right flags or input.\n I left the result of executing "
862 << "the program with the \"safe\" backend in this file for "
868 DisambiguateGlobalSymbols(Program);
870 std::vector<Function*> Funcs = DebugAMiscompilation(*this, TestCodeGenerator);
872 // Split the module into the two halves of the program we want.
873 DenseMap<const Value*, Value*> ValueMap;
874 Module *ToNotCodeGen = CloneModule(getProgram(), ValueMap);
875 Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs, ValueMap);
877 // Condition the modules
878 CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen);
880 sys::Path TestModuleBC("bugpoint.test.bc");
882 if (TestModuleBC.makeUnique(true, &ErrMsg)) {
883 errs() << getToolName() << "Error making unique filename: "
888 if (writeProgramToFile(TestModuleBC.str(), ToCodeGen)) {
889 errs() << "Error writing bitcode to `" << TestModuleBC.str()
895 // Make the shared library
896 sys::Path SafeModuleBC("bugpoint.safe.bc");
897 if (SafeModuleBC.makeUnique(true, &ErrMsg)) {
898 errs() << getToolName() << "Error making unique filename: "
903 if (writeProgramToFile(SafeModuleBC.str(), ToNotCodeGen)) {
904 errs() << "Error writing bitcode to `" << SafeModuleBC.str()
908 std::string SharedObject = compileSharedObject(SafeModuleBC.str());
911 outs() << "You can reproduce the problem with the command line: \n";
912 if (isExecutingJIT()) {
913 outs() << " lli -load " << SharedObject << " " << TestModuleBC.str();
915 outs() << " llc -f " << TestModuleBC.str() << " -o " << TestModuleBC.str()
917 outs() << " gcc " << SharedObject << " " << TestModuleBC.str()
918 << ".s -o " << TestModuleBC.str() << ".exe";
919 #if defined (HAVE_LINK_R)
920 outs() << " -Wl,-R.";
923 outs() << " " << TestModuleBC.str() << ".exe";
925 for (unsigned i=0, e = InputArgv.size(); i != e; ++i)
926 outs() << " " << InputArgv[i];
928 outs() << "The shared object was created with:\n llc -march=c "
929 << SafeModuleBC.str() << " -o temporary.c\n"
930 << " gcc -xc temporary.c -O2 -o " << SharedObject;
931 if (TargetTriple.getArch() == Triple::sparc)
932 outs() << " -G"; // Compile a shared library, `-G' for Sparc
934 outs() << " -fPIC -shared"; // `-shared' for Linux/X86, maybe others
936 outs() << " -fno-strict-aliasing\n";