1 //===- Miscompilation.cpp - Debug program miscompilations -----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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 "llvm/Constants.h"
18 #include "llvm/DerivedTypes.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/Linker.h"
21 #include "llvm/Module.h"
22 #include "llvm/Pass.h"
23 #include "llvm/Analysis/Verifier.h"
24 #include "llvm/Support/Mangler.h"
25 #include "llvm/Transforms/Utils/Cloning.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Support/FileUtilities.h"
31 extern cl::list<std::string> InputArgv;
35 class ReduceMiscompilingPasses : public ListReducer<const PassInfo*> {
38 ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
40 virtual TestResult doTest(std::vector<const PassInfo*> &Prefix,
41 std::vector<const PassInfo*> &Suffix);
45 /// TestResult - After passes have been split into a test group and a control
46 /// group, see if they still break the program.
48 ReduceMiscompilingPasses::TestResult
49 ReduceMiscompilingPasses::doTest(std::vector<const PassInfo*> &Prefix,
50 std::vector<const PassInfo*> &Suffix) {
51 // First, run the program with just the Suffix passes. If it is still broken
52 // with JUST the kept passes, discard the prefix passes.
53 std::cout << "Checking to see if '" << getPassesString(Suffix)
54 << "' compile correctly: ";
56 std::string BytecodeResult;
57 if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
58 std::cerr << " Error running this sequence of passes"
59 << " on the input program!\n";
60 BD.setPassesToRun(Suffix);
61 BD.EmitProgressBytecode("pass-error", false);
62 exit(BD.debugOptimizerCrash());
65 // Check to see if the finished program matches the reference output...
66 if (BD.diffProgram(BytecodeResult, "", true /*delete bytecode*/)) {
67 std::cout << " nope.\n";
68 return KeepSuffix; // Miscompilation detected!
70 std::cout << " yup.\n"; // No miscompilation!
72 if (Prefix.empty()) return NoFailure;
74 // Next, see if the program is broken if we run the "prefix" passes first,
75 // then separately run the "kept" passes.
76 std::cout << "Checking to see if '" << getPassesString(Prefix)
77 << "' compile correctly: ";
79 // If it is not broken with the kept passes, it's possible that the prefix
80 // passes must be run before the kept passes to break it. If the program
81 // WORKS after the prefix passes, but then fails if running the prefix AND
82 // kept passes, we can update our bytecode file to include the result of the
83 // prefix passes, then discard the prefix passes.
85 if (BD.runPasses(Prefix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
86 std::cerr << " Error running this sequence of passes"
87 << " on the input program!\n";
88 BD.setPassesToRun(Prefix);
89 BD.EmitProgressBytecode("pass-error", false);
90 exit(BD.debugOptimizerCrash());
93 // If the prefix maintains the predicate by itself, only keep the prefix!
94 if (BD.diffProgram(BytecodeResult)) {
95 std::cout << " nope.\n";
96 sys::Path(BytecodeResult).destroyFile();
99 std::cout << " yup.\n"; // No miscompilation!
101 // Ok, so now we know that the prefix passes work, try running the suffix
102 // passes on the result of the prefix passes.
104 Module *PrefixOutput = ParseInputFile(BytecodeResult);
105 if (PrefixOutput == 0) {
106 std::cerr << BD.getToolName() << ": Error reading bytecode file '"
107 << BytecodeResult << "'!\n";
110 sys::Path(BytecodeResult).destroyFile(); // No longer need the file on disk
112 // Don't check if there are no passes in the suffix.
116 std::cout << "Checking to see if '" << getPassesString(Suffix)
117 << "' passes compile correctly after the '"
118 << getPassesString(Prefix) << "' passes: ";
120 Module *OriginalInput = BD.swapProgramIn(PrefixOutput);
121 if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
122 std::cerr << " Error running this sequence of passes"
123 << " on the input program!\n";
124 BD.setPassesToRun(Suffix);
125 BD.EmitProgressBytecode("pass-error", false);
126 exit(BD.debugOptimizerCrash());
130 if (BD.diffProgram(BytecodeResult, "", true/*delete bytecode*/)) {
131 std::cout << " nope.\n";
132 delete OriginalInput; // We pruned down the original input...
136 // Otherwise, we must not be running the bad pass anymore.
137 std::cout << " yup.\n"; // No miscompilation!
138 delete BD.swapProgramIn(OriginalInput); // Restore orig program & free test
143 class ReduceMiscompilingFunctions : public ListReducer<Function*> {
145 bool (*TestFn)(BugDriver &, Module *, Module *);
147 ReduceMiscompilingFunctions(BugDriver &bd,
148 bool (*F)(BugDriver &, Module *, Module *))
149 : BD(bd), TestFn(F) {}
151 virtual TestResult doTest(std::vector<Function*> &Prefix,
152 std::vector<Function*> &Suffix) {
153 if (!Suffix.empty() && TestFuncs(Suffix))
155 if (!Prefix.empty() && TestFuncs(Prefix))
160 bool TestFuncs(const std::vector<Function*> &Prefix);
164 /// TestMergedProgram - Given two modules, link them together and run the
165 /// program, checking to see if the program matches the diff. If the diff
166 /// matches, return false, otherwise return true. If the DeleteInputs argument
167 /// is set to true then this function deletes both input modules before it
170 static bool TestMergedProgram(BugDriver &BD, Module *M1, Module *M2,
172 // Link the two portions of the program back to together.
173 std::string ErrorMsg;
175 M1 = CloneModule(M1);
176 M2 = CloneModule(M2);
178 if (Linker::LinkModules(M1, M2, &ErrorMsg)) {
179 std::cerr << BD.getToolName() << ": Error linking modules together:"
183 delete M2; // We are done with this module.
185 Module *OldProgram = BD.swapProgramIn(M1);
187 // Execute the program. If it does not match the expected output, we must
189 bool Broken = BD.diffProgram();
191 // Delete the linked module & restore the original
192 BD.swapProgramIn(OldProgram);
197 /// TestFuncs - split functions in a Module into two groups: those that are
198 /// under consideration for miscompilation vs. those that are not, and test
199 /// accordingly. Each group of functions becomes a separate Module.
201 bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*>&Funcs){
202 // Test to see if the function is misoptimized if we ONLY run it on the
203 // functions listed in Funcs.
204 std::cout << "Checking to see if the program is misoptimized when "
205 << (Funcs.size()==1 ? "this function is" : "these functions are")
206 << " run through the pass"
207 << (BD.getPassesToRun().size() == 1 ? "" : "es") << ":";
208 PrintFunctionList(Funcs);
211 // Split the module into the two halves of the program we want.
212 Module *ToNotOptimize = CloneModule(BD.getProgram());
213 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, Funcs);
215 // Run the predicate, not that the predicate will delete both input modules.
216 return TestFn(BD, ToOptimize, ToNotOptimize);
219 /// DisambiguateGlobalSymbols - Mangle symbols to guarantee uniqueness by
220 /// modifying predominantly internal symbols rather than external ones.
222 static void DisambiguateGlobalSymbols(Module *M) {
223 // Try not to cause collisions by minimizing chances of renaming an
224 // already-external symbol, so take in external globals and functions as-is.
225 // The code should work correctly without disambiguation (assuming the same
226 // mangler is used by the two code generators), but having symbols with the
227 // same name causes warnings to be emitted by the code generator.
229 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
230 I->setName(Mang.getValueName(I));
231 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
232 I->setName(Mang.getValueName(I));
235 /// ExtractLoops - Given a reduced list of functions that still exposed the bug,
236 /// check to see if we can extract the loops in the region without obscuring the
237 /// bug. If so, it reduces the amount of code identified.
239 static bool ExtractLoops(BugDriver &BD,
240 bool (*TestFn)(BugDriver &, Module *, Module *),
241 std::vector<Function*> &MiscompiledFunctions) {
242 bool MadeChange = false;
244 Module *ToNotOptimize = CloneModule(BD.getProgram());
245 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
246 MiscompiledFunctions);
247 Module *ToOptimizeLoopExtracted = BD.ExtractLoop(ToOptimize);
248 if (!ToOptimizeLoopExtracted) {
249 // If the loop extractor crashed or if there were no extractible loops,
250 // then this chapter of our odyssey is over with.
251 delete ToNotOptimize;
256 std::cerr << "Extracted a loop from the breaking portion of the program.\n";
259 // Bugpoint is intentionally not very trusting of LLVM transformations. In
260 // particular, we're not going to assume that the loop extractor works, so
261 // we're going to test the newly loop extracted program to make sure nothing
262 // has broken. If something broke, then we'll inform the user and stop
264 AbstractInterpreter *AI = BD.switchToCBE();
265 if (TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize, false)) {
266 BD.switchToInterpreter(AI);
268 // Merged program doesn't work anymore!
269 std::cerr << " *** ERROR: Loop extraction broke the program. :("
270 << " Please report a bug!\n";
271 std::cerr << " Continuing on with un-loop-extracted version.\n";
272 delete ToNotOptimize;
273 delete ToOptimizeLoopExtracted;
276 BD.switchToInterpreter(AI);
278 std::cout << " Testing after loop extraction:\n";
279 // Clone modules, the tester function will free them.
280 Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted);
281 Module *TNOBackup = CloneModule(ToNotOptimize);
282 if (!TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize)) {
283 std::cout << "*** Loop extraction masked the problem. Undoing.\n";
284 // If the program is not still broken, then loop extraction did something
285 // that masked the error. Stop loop extraction now.
290 ToOptimizeLoopExtracted = TOLEBackup;
291 ToNotOptimize = TNOBackup;
293 std::cout << "*** Loop extraction successful!\n";
295 std::vector<std::pair<std::string, const FunctionType*> > MisCompFunctions;
296 for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
297 E = ToOptimizeLoopExtracted->end(); I != E; ++I)
298 if (!I->isExternal())
299 MisCompFunctions.push_back(std::make_pair(I->getName(),
300 I->getFunctionType()));
302 // Okay, great! Now we know that we extracted a loop and that loop
303 // extraction both didn't break the program, and didn't mask the problem.
304 // Replace the current program with the loop extracted version, and try to
305 // extract another loop.
306 std::string ErrorMsg;
307 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted, &ErrorMsg)){
308 std::cerr << BD.getToolName() << ": Error linking modules together:"
312 delete ToOptimizeLoopExtracted;
314 // All of the Function*'s in the MiscompiledFunctions list are in the old
315 // module. Update this list to include all of the functions in the
316 // optimized and loop extracted module.
317 MiscompiledFunctions.clear();
318 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
319 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first,
320 MisCompFunctions[i].second);
321 assert(NewF && "Function not found??");
322 MiscompiledFunctions.push_back(NewF);
325 BD.setNewProgram(ToNotOptimize);
331 class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> {
333 bool (*TestFn)(BugDriver &, Module *, Module *);
334 std::vector<Function*> FunctionsBeingTested;
336 ReduceMiscompiledBlocks(BugDriver &bd,
337 bool (*F)(BugDriver &, Module *, Module *),
338 const std::vector<Function*> &Fns)
339 : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {}
341 virtual TestResult doTest(std::vector<BasicBlock*> &Prefix,
342 std::vector<BasicBlock*> &Suffix) {
343 if (!Suffix.empty() && TestFuncs(Suffix))
345 if (TestFuncs(Prefix))
350 bool TestFuncs(const std::vector<BasicBlock*> &Prefix);
354 /// TestFuncs - Extract all blocks for the miscompiled functions except for the
355 /// specified blocks. If the problem still exists, return true.
357 bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs) {
358 // Test to see if the function is misoptimized if we ONLY run it on the
359 // functions listed in Funcs.
360 std::cout << "Checking to see if the program is misoptimized when all ";
362 std::cout << "but these " << BBs.size() << " blocks are extracted: ";
363 for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i)
364 std::cout << BBs[i]->getName() << " ";
365 if (BBs.size() > 10) std::cout << "...";
367 std::cout << "blocks are extracted.";
371 // Split the module into the two halves of the program we want.
372 Module *ToNotOptimize = CloneModule(BD.getProgram());
373 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
374 FunctionsBeingTested);
376 // Try the extraction. If it doesn't work, then the block extractor crashed
377 // or something, in which case bugpoint can't chase down this possibility.
378 if (Module *New = BD.ExtractMappedBlocksFromModule(BBs, ToOptimize)) {
380 // Run the predicate, not that the predicate will delete both input modules.
381 return TestFn(BD, New, ToNotOptimize);
384 delete ToNotOptimize;
389 /// ExtractBlocks - Given a reduced list of functions that still expose the bug,
390 /// extract as many basic blocks from the region as possible without obscuring
393 static bool ExtractBlocks(BugDriver &BD,
394 bool (*TestFn)(BugDriver &, Module *, Module *),
395 std::vector<Function*> &MiscompiledFunctions) {
396 std::vector<BasicBlock*> Blocks;
397 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
398 for (Function::iterator I = MiscompiledFunctions[i]->begin(),
399 E = MiscompiledFunctions[i]->end(); I != E; ++I)
402 // Use the list reducer to identify blocks that can be extracted without
403 // obscuring the bug. The Blocks list will end up containing blocks that must
404 // be retained from the original program.
405 unsigned OldSize = Blocks.size();
407 // Check to see if all blocks are extractible first.
408 if (ReduceMiscompiledBlocks(BD, TestFn,
409 MiscompiledFunctions).TestFuncs(std::vector<BasicBlock*>())) {
412 ReduceMiscompiledBlocks(BD, TestFn,MiscompiledFunctions).reduceList(Blocks);
413 if (Blocks.size() == OldSize)
417 Module *ProgClone = CloneModule(BD.getProgram());
418 Module *ToExtract = SplitFunctionsOutOfModule(ProgClone,
419 MiscompiledFunctions);
420 Module *Extracted = BD.ExtractMappedBlocksFromModule(Blocks, ToExtract);
421 if (Extracted == 0) {
422 // Wierd, extraction should have worked.
423 std::cerr << "Nondeterministic problem extracting blocks??\n";
429 // Otherwise, block extraction succeeded. Link the two program fragments back
433 std::vector<std::pair<std::string, const FunctionType*> > MisCompFunctions;
434 for (Module::iterator I = Extracted->begin(), E = Extracted->end();
436 if (!I->isExternal())
437 MisCompFunctions.push_back(std::make_pair(I->getName(),
438 I->getFunctionType()));
440 std::string ErrorMsg;
441 if (Linker::LinkModules(ProgClone, Extracted, &ErrorMsg)) {
442 std::cerr << BD.getToolName() << ": Error linking modules together:"
448 // Set the new program and delete the old one.
449 BD.setNewProgram(ProgClone);
451 // Update the list of miscompiled functions.
452 MiscompiledFunctions.clear();
454 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
455 Function *NewF = ProgClone->getFunction(MisCompFunctions[i].first,
456 MisCompFunctions[i].second);
457 assert(NewF && "Function not found??");
458 MiscompiledFunctions.push_back(NewF);
465 /// DebugAMiscompilation - This is a generic driver to narrow down
466 /// miscompilations, either in an optimization or a code generator.
468 static std::vector<Function*>
469 DebugAMiscompilation(BugDriver &BD,
470 bool (*TestFn)(BugDriver &, Module *, Module *)) {
471 // Okay, now that we have reduced the list of passes which are causing the
472 // failure, see if we can pin down which functions are being
473 // miscompiled... first build a list of all of the non-external functions in
475 std::vector<Function*> MiscompiledFunctions;
476 Module *Prog = BD.getProgram();
477 for (Module::iterator I = Prog->begin(), E = Prog->end(); I != E; ++I)
478 if (!I->isExternal())
479 MiscompiledFunctions.push_back(I);
481 // Do the reduction...
482 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
484 std::cout << "\n*** The following function"
485 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
486 << " being miscompiled: ";
487 PrintFunctionList(MiscompiledFunctions);
490 // See if we can rip any loops out of the miscompiled functions and still
491 // trigger the problem.
492 if (ExtractLoops(BD, TestFn, MiscompiledFunctions)) {
493 // Okay, we extracted some loops and the problem still appears. See if we
494 // can eliminate some of the created functions from being candidates.
496 // Loop extraction can introduce functions with the same name (foo_code).
497 // Make sure to disambiguate the symbols so that when the program is split
498 // apart that we can link it back together again.
499 DisambiguateGlobalSymbols(BD.getProgram());
501 // Do the reduction...
502 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
504 std::cout << "\n*** The following function"
505 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
506 << " being miscompiled: ";
507 PrintFunctionList(MiscompiledFunctions);
511 if (ExtractBlocks(BD, TestFn, MiscompiledFunctions)) {
512 // Okay, we extracted some blocks and the problem still appears. See if we
513 // can eliminate some of the created functions from being candidates.
515 // Block extraction can introduce functions with the same name (foo_code).
516 // Make sure to disambiguate the symbols so that when the program is split
517 // apart that we can link it back together again.
518 DisambiguateGlobalSymbols(BD.getProgram());
520 // Do the reduction...
521 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
523 std::cout << "\n*** The following function"
524 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
525 << " being miscompiled: ";
526 PrintFunctionList(MiscompiledFunctions);
530 return MiscompiledFunctions;
533 /// TestOptimizer - This is the predicate function used to check to see if the
534 /// "Test" portion of the program is misoptimized. If so, return true. In any
535 /// case, both module arguments are deleted.
537 static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe) {
538 // Run the optimization passes on ToOptimize, producing a transformed version
539 // of the functions being tested.
540 std::cout << " Optimizing functions being tested: ";
541 Module *Optimized = BD.runPassesOn(Test, BD.getPassesToRun(),
542 /*AutoDebugCrashes*/true);
543 std::cout << "done.\n";
546 std::cout << " Checking to see if the merged program executes correctly: ";
547 bool Broken = TestMergedProgram(BD, Optimized, Safe, true);
548 std::cout << (Broken ? " nope.\n" : " yup.\n");
553 /// debugMiscompilation - This method is used when the passes selected are not
554 /// crashing, but the generated output is semantically different from the
557 bool BugDriver::debugMiscompilation() {
558 // Make sure something was miscompiled...
559 if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun)) {
560 std::cerr << "*** Optimized program matches reference output! No problem "
561 << "detected...\nbugpoint can't help you with your problem!\n";
565 std::cout << "\n*** Found miscompiling pass"
566 << (getPassesToRun().size() == 1 ? "" : "es") << ": "
567 << getPassesString(getPassesToRun()) << '\n';
568 EmitProgressBytecode("passinput");
570 std::vector<Function*> MiscompiledFunctions =
571 DebugAMiscompilation(*this, TestOptimizer);
573 // Output a bunch of bytecode files for the user...
574 std::cout << "Outputting reduced bytecode files which expose the problem:\n";
575 Module *ToNotOptimize = CloneModule(getProgram());
576 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
577 MiscompiledFunctions);
579 std::cout << " Non-optimized portion: ";
580 ToNotOptimize = swapProgramIn(ToNotOptimize);
581 EmitProgressBytecode("tonotoptimize", true);
582 setNewProgram(ToNotOptimize); // Delete hacked module.
584 std::cout << " Portion that is input to optimizer: ";
585 ToOptimize = swapProgramIn(ToOptimize);
586 EmitProgressBytecode("tooptimize");
587 setNewProgram(ToOptimize); // Delete hacked module.
592 /// CleanupAndPrepareModules - Get the specified modules ready for code
593 /// generator testing.
595 static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
597 // Clean up the modules, removing extra cruft that we don't need anymore...
598 Test = BD.performFinalCleanups(Test);
600 // If we are executing the JIT, we have several nasty issues to take care of.
601 if (!BD.isExecutingJIT()) return;
603 // First, if the main function is in the Safe module, we must add a stub to
604 // the Test module to call into it. Thus, we create a new function `main'
605 // which just calls the old one.
606 if (Function *oldMain = Safe->getNamedFunction("main"))
607 if (!oldMain->isExternal()) {
609 oldMain->setName("llvm_bugpoint_old_main");
610 // Create a NEW `main' function with same type in the test module.
611 Function *newMain = new Function(oldMain->getFunctionType(),
612 GlobalValue::ExternalLinkage,
614 // Create an `oldmain' prototype in the test module, which will
615 // corresponds to the real main function in the same module.
616 Function *oldMainProto = new Function(oldMain->getFunctionType(),
617 GlobalValue::ExternalLinkage,
618 oldMain->getName(), Test);
619 // Set up and remember the argument list for the main function.
620 std::vector<Value*> args;
621 for (Function::aiterator I = newMain->abegin(), E = newMain->aend(),
622 OI = oldMain->abegin(); I != E; ++I, ++OI) {
623 I->setName(OI->getName()); // Copy argument names from oldMain
627 // Call the old main function and return its result
628 BasicBlock *BB = new BasicBlock("entry", newMain);
629 CallInst *call = new CallInst(oldMainProto, args, "", BB);
631 // If the type of old function wasn't void, return value of call
632 new ReturnInst(call, BB);
635 // The second nasty issue we must deal with in the JIT is that the Safe
636 // module cannot directly reference any functions defined in the test
637 // module. Instead, we use a JIT API call to dynamically resolve the
640 // Add the resolver to the Safe module.
641 // Prototype: void *getPointerToNamedFunction(const char* Name)
642 Function *resolverFunc =
643 Safe->getOrInsertFunction("getPointerToNamedFunction",
644 PointerType::get(Type::SByteTy),
645 PointerType::get(Type::SByteTy), 0);
647 // Use the function we just added to get addresses of functions we need.
648 for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) {
649 if (F->isExternal() && !F->use_empty() && &*F != resolverFunc &&
650 F->getIntrinsicID() == 0 /* ignore intrinsics */) {
651 Function *TestFn = Test->getFunction(F->getName(), F->getFunctionType());
653 // Don't forward functions which are external in the test module too.
654 if (TestFn && !TestFn->isExternal()) {
655 // 1. Add a string constant with its name to the global file
656 Constant *InitArray = ConstantArray::get(F->getName());
657 GlobalVariable *funcName =
658 new GlobalVariable(InitArray->getType(), true /*isConstant*/,
659 GlobalValue::InternalLinkage, InitArray,
660 F->getName() + "_name", Safe);
662 // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
663 // sbyte* so it matches the signature of the resolver function.
665 // GetElementPtr *funcName, ulong 0, ulong 0
666 std::vector<Constant*> GEPargs(2,Constant::getNullValue(Type::IntTy));
668 ConstantExpr::getGetElementPtr(funcName, GEPargs);
669 std::vector<Value*> ResolverArgs;
670 ResolverArgs.push_back(GEP);
672 // Rewrite uses of F in global initializers, etc. to uses of a wrapper
673 // function that dynamically resolves the calls to F via our JIT API
674 if (F->use_begin() != F->use_end()) {
675 // Construct a new stub function that will re-route calls to F
676 const FunctionType *FuncTy = F->getFunctionType();
677 Function *FuncWrapper = new Function(FuncTy,
678 GlobalValue::InternalLinkage,
679 F->getName() + "_wrapper",
681 BasicBlock *Header = new BasicBlock("header", FuncWrapper);
683 // Resolve the call to function F via the JIT API:
685 // call resolver(GetElementPtr...)
686 CallInst *resolve = new CallInst(resolverFunc, ResolverArgs,
688 Header->getInstList().push_back(resolve);
689 // cast the result from the resolver to correctly-typed function
690 CastInst *castResolver =
691 new CastInst(resolve, PointerType::get(F->getFunctionType()),
693 Header->getInstList().push_back(castResolver);
695 // Save the argument list
696 std::vector<Value*> Args;
697 for (Function::aiterator i = FuncWrapper->abegin(),
698 e = FuncWrapper->aend(); i != e; ++i)
701 // Pass on the arguments to the real function, return its result
702 if (F->getReturnType() == Type::VoidTy) {
703 CallInst *Call = new CallInst(castResolver, Args);
704 Header->getInstList().push_back(Call);
705 ReturnInst *Ret = new ReturnInst();
706 Header->getInstList().push_back(Ret);
708 CallInst *Call = new CallInst(castResolver, Args, "redir");
709 Header->getInstList().push_back(Call);
710 ReturnInst *Ret = new ReturnInst(Call);
711 Header->getInstList().push_back(Ret);
714 // Use the wrapper function instead of the old function
715 F->replaceAllUsesWith(FuncWrapper);
721 if (verifyModule(*Test) || verifyModule(*Safe)) {
722 std::cerr << "Bugpoint has a bug, which corrupted a module!!\n";
729 /// TestCodeGenerator - This is the predicate function used to check to see if
730 /// the "Test" portion of the program is miscompiled by the code generator under
731 /// test. If so, return true. In any case, both module arguments are deleted.
733 static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe) {
734 CleanupAndPrepareModules(BD, Test, Safe);
736 sys::Path TestModuleBC("bugpoint.test.bc");
737 TestModuleBC.makeUnique();
738 if (BD.writeProgramToFile(TestModuleBC.toString(), Test)) {
739 std::cerr << "Error writing bytecode to `" << TestModuleBC << "'\nExiting.";
744 // Make the shared library
745 sys::Path SafeModuleBC("bugpoint.safe.bc");
746 SafeModuleBC.makeUnique();
748 if (BD.writeProgramToFile(SafeModuleBC.toString(), Safe)) {
749 std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting.";
752 std::string SharedObject = BD.compileSharedObject(SafeModuleBC.toString());
755 // Run the code generator on the `Test' code, loading the shared library.
756 // The function returns whether or not the new output differs from reference.
757 int Result = BD.diffProgram(TestModuleBC.toString(), SharedObject, false);
760 std::cerr << ": still failing!\n";
762 std::cerr << ": didn't fail.\n";
763 TestModuleBC.destroyFile();
764 SafeModuleBC.destroyFile();
765 sys::Path(SharedObject).destroyFile();
771 /// debugCodeGenerator - debug errors in LLC, LLI, or CBE.
773 bool BugDriver::debugCodeGenerator() {
774 if ((void*)cbe == (void*)Interpreter) {
775 std::string Result = executeProgramWithCBE("bugpoint.cbe.out");
776 std::cout << "\n*** The C backend cannot match the reference diff, but it "
777 << "is used as the 'known good'\n code generator, so I can't"
778 << " debug it. Perhaps you have a front-end problem?\n As a"
779 << " sanity check, I left the result of executing the program "
780 << "with the C backend\n in this file for you: '"
785 DisambiguateGlobalSymbols(Program);
787 std::vector<Function*> Funcs = DebugAMiscompilation(*this, TestCodeGenerator);
789 // Split the module into the two halves of the program we want.
790 Module *ToNotCodeGen = CloneModule(getProgram());
791 Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs);
793 // Condition the modules
794 CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen);
796 sys::Path TestModuleBC("bugpoint.test.bc");
797 TestModuleBC.makeUnique();
799 if (writeProgramToFile(TestModuleBC.toString(), ToCodeGen)) {
800 std::cerr << "Error writing bytecode to `" << TestModuleBC << "'\nExiting.";
805 // Make the shared library
806 sys::Path SafeModuleBC("bugpoint.safe.bc");
807 SafeModuleBC.makeUnique();
809 if (writeProgramToFile(SafeModuleBC.toString(), ToNotCodeGen)) {
810 std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting.";
813 std::string SharedObject = compileSharedObject(SafeModuleBC.toString());
816 std::cout << "You can reproduce the problem with the command line: \n";
817 if (isExecutingJIT()) {
818 std::cout << " lli -load " << SharedObject << " " << TestModuleBC;
820 std::cout << " llc " << TestModuleBC << " -o " << TestModuleBC << ".s\n";
821 std::cout << " gcc " << SharedObject << " " << TestModuleBC
822 << ".s -o " << TestModuleBC << ".exe -Wl,-R.\n";
823 std::cout << " " << TestModuleBC << ".exe";
825 for (unsigned i=0, e = InputArgv.size(); i != e; ++i)
826 std::cout << " " << InputArgv[i];
828 std::cout << "The shared object was created with:\n llc -march=c "
829 << SafeModuleBC << " -o temporary.c\n"
830 << " gcc -xc temporary.c -O2 -o " << SharedObject
831 #if defined(sparc) || defined(__sparc__) || defined(__sparcv9)
832 << " -G" // Compile a shared library, `-G' for Sparc
834 << " -shared" // `-shared' for Linux/X86, maybe others
836 << " -fno-strict-aliasing\n";