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/Module.h"
21 #include "llvm/Pass.h"
22 #include "llvm/Analysis/Verifier.h"
23 #include "llvm/Support/Mangler.h"
24 #include "llvm/Transforms/Utils/Cloning.h"
25 #include "llvm/Transforms/Utils/Linker.h"
26 #include "Support/CommandLine.h"
27 #include "Support/FileUtilities.h"
31 extern cl::list<std::string> InputArgv;
33 EnableBlockExtraction("enable-block-extraction",
34 cl::desc("Enable basic block extraction for "
35 "miscompilation debugging (experimental)"));
39 class ReduceMiscompilingPasses : public ListReducer<const PassInfo*> {
42 ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
44 virtual TestResult doTest(std::vector<const PassInfo*> &Prefix,
45 std::vector<const PassInfo*> &Suffix);
49 /// TestResult - After passes have been split into a test group and a control
50 /// group, see if they still break the program.
52 ReduceMiscompilingPasses::TestResult
53 ReduceMiscompilingPasses::doTest(std::vector<const PassInfo*> &Prefix,
54 std::vector<const PassInfo*> &Suffix) {
55 // First, run the program with just the Suffix passes. If it is still broken
56 // with JUST the kept passes, discard the prefix passes.
57 std::cout << "Checking to see if '" << getPassesString(Suffix)
58 << "' compile correctly: ";
60 std::string BytecodeResult;
61 if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
62 std::cerr << " Error running this sequence of passes"
63 << " on the input program!\n";
64 BD.setPassesToRun(Suffix);
65 BD.EmitProgressBytecode("pass-error", false);
66 exit(BD.debugOptimizerCrash());
69 // Check to see if the finished program matches the reference output...
70 if (BD.diffProgram(BytecodeResult, "", true /*delete bytecode*/)) {
71 std::cout << " nope.\n";
72 return KeepSuffix; // Miscompilation detected!
74 std::cout << " yup.\n"; // No miscompilation!
76 if (Prefix.empty()) return NoFailure;
78 // Next, see if the program is broken if we run the "prefix" passes first,
79 // then separately run the "kept" passes.
80 std::cout << "Checking to see if '" << getPassesString(Prefix)
81 << "' compile correctly: ";
83 // If it is not broken with the kept passes, it's possible that the prefix
84 // passes must be run before the kept passes to break it. If the program
85 // WORKS after the prefix passes, but then fails if running the prefix AND
86 // kept passes, we can update our bytecode file to include the result of the
87 // prefix passes, then discard the prefix passes.
89 if (BD.runPasses(Prefix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
90 std::cerr << " Error running this sequence of passes"
91 << " on the input program!\n";
92 BD.setPassesToRun(Prefix);
93 BD.EmitProgressBytecode("pass-error", false);
94 exit(BD.debugOptimizerCrash());
97 // If the prefix maintains the predicate by itself, only keep the prefix!
98 if (BD.diffProgram(BytecodeResult)) {
99 std::cout << " nope.\n";
100 removeFile(BytecodeResult);
103 std::cout << " yup.\n"; // No miscompilation!
105 // Ok, so now we know that the prefix passes work, try running the suffix
106 // passes on the result of the prefix passes.
108 Module *PrefixOutput = ParseInputFile(BytecodeResult);
109 if (PrefixOutput == 0) {
110 std::cerr << BD.getToolName() << ": Error reading bytecode file '"
111 << BytecodeResult << "'!\n";
114 removeFile(BytecodeResult); // No longer need the file on disk
116 // Don't check if there are no passes in the suffix.
120 std::cout << "Checking to see if '" << getPassesString(Suffix)
121 << "' passes compile correctly after the '"
122 << getPassesString(Prefix) << "' passes: ";
124 Module *OriginalInput = BD.swapProgramIn(PrefixOutput);
125 if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
126 std::cerr << " Error running this sequence of passes"
127 << " on the input program!\n";
128 BD.setPassesToRun(Suffix);
129 BD.EmitProgressBytecode("pass-error", false);
130 exit(BD.debugOptimizerCrash());
134 if (BD.diffProgram(BytecodeResult, "", true/*delete bytecode*/)) {
135 std::cout << " nope.\n";
136 delete OriginalInput; // We pruned down the original input...
140 // Otherwise, we must not be running the bad pass anymore.
141 std::cout << " yup.\n"; // No miscompilation!
142 delete BD.swapProgramIn(OriginalInput); // Restore orig program & free test
147 class ReduceMiscompilingFunctions : public ListReducer<Function*> {
149 bool (*TestFn)(BugDriver &, Module *, Module *);
151 ReduceMiscompilingFunctions(BugDriver &bd,
152 bool (*F)(BugDriver &, Module *, Module *))
153 : BD(bd), TestFn(F) {}
155 virtual TestResult doTest(std::vector<Function*> &Prefix,
156 std::vector<Function*> &Suffix) {
157 if (!Suffix.empty() && TestFuncs(Suffix))
159 if (!Prefix.empty() && TestFuncs(Prefix))
164 bool TestFuncs(const std::vector<Function*> &Prefix);
168 /// TestMergedProgram - Given two modules, link them together and run the
169 /// program, checking to see if the program matches the diff. If the diff
170 /// matches, return false, otherwise return true. If the DeleteInputs argument
171 /// is set to true then this function deletes both input modules before it
174 static bool TestMergedProgram(BugDriver &BD, Module *M1, Module *M2,
176 // Link the two portions of the program back to together.
177 std::string ErrorMsg;
178 if (!DeleteInputs) M1 = CloneModule(M1);
179 if (LinkModules(M1, M2, &ErrorMsg)) {
180 std::cerr << BD.getToolName() << ": Error linking modules together:"
184 if (DeleteInputs) delete M2; // We are done with this module...
186 Module *OldProgram = BD.swapProgramIn(M1);
188 // Execute the program. If it does not match the expected output, we must
190 bool Broken = BD.diffProgram();
192 // Delete the linked module & restore the original
193 BD.swapProgramIn(OldProgram);
198 /// TestFuncs - split functions in a Module into two groups: those that are
199 /// under consideration for miscompilation vs. those that are not, and test
200 /// accordingly. Each group of functions becomes a separate Module.
202 bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*>&Funcs){
203 // Test to see if the function is misoptimized if we ONLY run it on the
204 // functions listed in Funcs.
205 std::cout << "Checking to see if the program is misoptimized when "
206 << (Funcs.size()==1 ? "this function is" : "these functions are")
207 << " run through the pass"
208 << (BD.getPassesToRun().size() == 1 ? "" : "es") << ":";
209 PrintFunctionList(Funcs);
212 // Split the module into the two halves of the program we want.
213 Module *ToNotOptimize = CloneModule(BD.getProgram());
214 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, Funcs);
216 // Run the predicate, not that the predicate will delete both input modules.
217 return TestFn(BD, ToOptimize, ToNotOptimize);
220 /// DisambiguateGlobalSymbols - Mangle symbols to guarantee uniqueness by
221 /// modifying predominantly internal symbols rather than external ones.
223 static void DisambiguateGlobalSymbols(Module *M) {
224 // Try not to cause collisions by minimizing chances of renaming an
225 // already-external symbol, so take in external globals and functions as-is.
226 // The code should work correctly without disambiguation (assuming the same
227 // mangler is used by the two code generators), but having symbols with the
228 // same name causes warnings to be emitted by the code generator.
230 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
231 I->setName(Mang.getValueName(I));
232 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
233 I->setName(Mang.getValueName(I));
236 /// ExtractLoops - Given a reduced list of functions that still exposed the bug,
237 /// check to see if we can extract the loops in the region without obscuring the
238 /// bug. If so, it reduces the amount of code identified.
240 static bool ExtractLoops(BugDriver &BD,
241 bool (*TestFn)(BugDriver &, Module *, Module *),
242 std::vector<Function*> &MiscompiledFunctions) {
243 bool MadeChange = false;
245 Module *ToNotOptimize = CloneModule(BD.getProgram());
246 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
247 MiscompiledFunctions);
248 Module *ToOptimizeLoopExtracted = BD.ExtractLoop(ToOptimize);
249 if (!ToOptimizeLoopExtracted) {
250 // If the loop extractor crashed or if there were no extractible loops,
251 // then this chapter of our odyssey is over with.
252 delete ToNotOptimize;
257 std::cerr << "Extracted a loop from the breaking portion of the program.\n";
260 // Bugpoint is intentionally not very trusting of LLVM transformations. In
261 // particular, we're not going to assume that the loop extractor works, so
262 // we're going to test the newly loop extracted program to make sure nothing
263 // has broken. If something broke, then we'll inform the user and stop
265 AbstractInterpreter *AI = BD.switchToCBE();
266 if (TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize, false)) {
267 BD.switchToInterpreter(AI);
269 // Merged program doesn't work anymore!
270 std::cerr << " *** ERROR: Loop extraction broke the program. :("
271 << " Please report a bug!\n";
272 std::cerr << " Continuing on with un-loop-extracted version.\n";
273 delete ToNotOptimize;
274 delete ToOptimizeLoopExtracted;
277 BD.switchToInterpreter(AI);
279 std::cout << " Testing after loop extraction:\n";
280 // Clone modules, the tester function will free them.
281 Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted);
282 Module *TNOBackup = CloneModule(ToNotOptimize);
283 if (!TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize)) {
284 std::cout << "*** Loop extraction masked the problem. Undoing.\n";
285 // If the program is not still broken, then loop extraction did something
286 // that masked the error. Stop loop extraction now.
291 ToOptimizeLoopExtracted = TOLEBackup;
292 ToNotOptimize = TNOBackup;
294 std::cout << "*** Loop extraction successful!\n";
296 // Okay, great! Now we know that we extracted a loop and that loop
297 // extraction both didn't break the program, and didn't mask the problem.
298 // Replace the current program with the loop extracted version, and try to
299 // extract another loop.
300 std::string ErrorMsg;
301 if (LinkModules(ToNotOptimize, ToOptimizeLoopExtracted, &ErrorMsg)) {
302 std::cerr << BD.getToolName() << ": Error linking modules together:"
307 // All of the Function*'s in the MiscompiledFunctions list are in the old
308 // module. Update this list to include all of the functions in the
309 // optimized and loop extracted module.
310 MiscompiledFunctions.clear();
311 for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
312 E = ToOptimizeLoopExtracted->end(); I != E; ++I) {
313 if (!I->isExternal()) {
314 Function *NewF = ToNotOptimize->getFunction(I->getName(),
315 I->getFunctionType());
316 assert(NewF && "Function not found??");
317 MiscompiledFunctions.push_back(NewF);
320 delete ToOptimizeLoopExtracted;
322 BD.setNewProgram(ToNotOptimize);
328 class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> {
330 bool (*TestFn)(BugDriver &, Module *, Module *);
331 std::vector<Function*> FunctionsBeingTested;
333 ReduceMiscompiledBlocks(BugDriver &bd,
334 bool (*F)(BugDriver &, Module *, Module *),
335 const std::vector<Function*> &Fns)
336 : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {}
338 virtual TestResult doTest(std::vector<BasicBlock*> &Prefix,
339 std::vector<BasicBlock*> &Suffix) {
340 if (!Suffix.empty() && TestFuncs(Suffix))
342 if (TestFuncs(Prefix))
347 bool TestFuncs(const std::vector<BasicBlock*> &Prefix);
351 /// TestFuncs - Extract all blocks for the miscompiled functions except for the
352 /// specified blocks. If the problem still exists, return true.
354 bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs) {
355 // Test to see if the function is misoptimized if we ONLY run it on the
356 // functions listed in Funcs.
357 std::cout << "Checking to see if the program is misoptimized when all ";
359 std::cout << "but these " << BBs.size() << " blocks are extracted: ";
360 for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i)
361 std::cout << BBs[i]->getName() << " ";
362 if (BBs.size() > 10) std::cout << "...";
364 std::cout << "blocks are extracted.";
368 // Split the module into the two halves of the program we want.
369 Module *ToNotOptimize = CloneModule(BD.getProgram());
370 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
371 FunctionsBeingTested);
373 // Try the extraction. If it doesn't work, then the block extractor crashed
374 // or something, in which case bugpoint can't chase down this possibility.
375 if (Module *New = BD.ExtractMappedBlocksFromModule(BBs, ToOptimize)) {
377 // Run the predicate, not that the predicate will delete both input modules.
378 return TestFn(BD, New, ToNotOptimize);
381 delete ToNotOptimize;
386 /// ExtractBlocks - Given a reduced list of functions that still expose the bug,
387 /// extract as many basic blocks from the region as possible without obscuring
390 static bool ExtractBlocks(BugDriver &BD,
391 bool (*TestFn)(BugDriver &, Module *, Module *),
392 std::vector<Function*> &MiscompiledFunctions) {
394 if (!EnableBlockExtraction) return false;
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::string ErrorMsg;
434 if (LinkModules(ProgClone, Extracted, &ErrorMsg)) {
435 std::cerr << BD.getToolName() << ": Error linking modules together:"
440 // Set the new program and delete the old one.
441 BD.setNewProgram(ProgClone);
443 // Update the list of miscompiled functions.
444 MiscompiledFunctions.clear();
446 for (Module::iterator I = Extracted->begin(), E = Extracted->end(); I != E;
448 if (!I->isExternal()) {
449 Function *NF = ProgClone->getFunction(I->getName(), I->getFunctionType());
450 assert(NF && "Mapped function not found!");
451 MiscompiledFunctions.push_back(NF);
460 /// DebugAMiscompilation - This is a generic driver to narrow down
461 /// miscompilations, either in an optimization or a code generator.
463 static std::vector<Function*>
464 DebugAMiscompilation(BugDriver &BD,
465 bool (*TestFn)(BugDriver &, Module *, Module *)) {
466 // Okay, now that we have reduced the list of passes which are causing the
467 // failure, see if we can pin down which functions are being
468 // miscompiled... first build a list of all of the non-external functions in
470 std::vector<Function*> MiscompiledFunctions;
471 Module *Prog = BD.getProgram();
472 for (Module::iterator I = Prog->begin(), E = Prog->end(); I != E; ++I)
473 if (!I->isExternal())
474 MiscompiledFunctions.push_back(I);
476 // Do the reduction...
477 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
479 std::cout << "\n*** The following function"
480 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
481 << " being miscompiled: ";
482 PrintFunctionList(MiscompiledFunctions);
485 // See if we can rip any loops out of the miscompiled functions and still
486 // trigger the problem.
487 if (ExtractLoops(BD, TestFn, MiscompiledFunctions)) {
488 // Okay, we extracted some loops and the problem still appears. See if we
489 // can eliminate some of the created functions from being candidates.
491 // Loop extraction can introduce functions with the same name (foo_code).
492 // Make sure to disambiguate the symbols so that when the program is split
493 // apart that we can link it back together again.
494 DisambiguateGlobalSymbols(BD.getProgram());
496 // Do the reduction...
497 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
499 std::cout << "\n*** The following function"
500 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
501 << " being miscompiled: ";
502 PrintFunctionList(MiscompiledFunctions);
506 if (ExtractBlocks(BD, TestFn, MiscompiledFunctions)) {
507 // Okay, we extracted some blocks and the problem still appears. See if we
508 // can eliminate some of the created functions from being candidates.
510 // Block extraction can introduce functions with the same name (foo_code).
511 // Make sure to disambiguate the symbols so that when the program is split
512 // apart that we can link it back together again.
513 DisambiguateGlobalSymbols(BD.getProgram());
515 // Do the reduction...
516 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
518 std::cout << "\n*** The following function"
519 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
520 << " being miscompiled: ";
521 PrintFunctionList(MiscompiledFunctions);
525 return MiscompiledFunctions;
528 /// TestOptimizer - This is the predicate function used to check to see if the
529 /// "Test" portion of the program is misoptimized. If so, return true. In any
530 /// case, both module arguments are deleted.
532 static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe) {
533 // Run the optimization passes on ToOptimize, producing a transformed version
534 // of the functions being tested.
535 std::cout << " Optimizing functions being tested: ";
536 Module *Optimized = BD.runPassesOn(Test, BD.getPassesToRun(),
537 /*AutoDebugCrashes*/true);
538 std::cout << "done.\n";
541 std::cout << " Checking to see if the merged program executes correctly: ";
542 bool Broken = TestMergedProgram(BD, Optimized, Safe, true);
543 std::cout << (Broken ? " nope.\n" : " yup.\n");
548 /// debugMiscompilation - This method is used when the passes selected are not
549 /// crashing, but the generated output is semantically different from the
552 bool BugDriver::debugMiscompilation() {
553 // Make sure something was miscompiled...
554 if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun)) {
555 std::cerr << "*** Optimized program matches reference output! No problem "
556 << "detected...\nbugpoint can't help you with your problem!\n";
560 std::cout << "\n*** Found miscompiling pass"
561 << (getPassesToRun().size() == 1 ? "" : "es") << ": "
562 << getPassesString(getPassesToRun()) << "\n";
563 EmitProgressBytecode("passinput");
565 std::vector<Function*> MiscompiledFunctions =
566 DebugAMiscompilation(*this, TestOptimizer);
568 // Output a bunch of bytecode files for the user...
569 std::cout << "Outputting reduced bytecode files which expose the problem:\n";
570 Module *ToNotOptimize = CloneModule(getProgram());
571 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
572 MiscompiledFunctions);
574 std::cout << " Non-optimized portion: ";
575 ToNotOptimize = swapProgramIn(ToNotOptimize);
576 EmitProgressBytecode("tonotoptimize", true);
577 setNewProgram(ToNotOptimize); // Delete hacked module.
579 std::cout << " Portion that is input to optimizer: ";
580 ToOptimize = swapProgramIn(ToOptimize);
581 EmitProgressBytecode("tooptimize");
582 setNewProgram(ToOptimize); // Delete hacked module.
587 /// CleanupAndPrepareModules - Get the specified modules ready for code
588 /// generator testing.
590 static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
592 // Clean up the modules, removing extra cruft that we don't need anymore...
593 Test = BD.performFinalCleanups(Test);
595 // If we are executing the JIT, we have several nasty issues to take care of.
596 if (!BD.isExecutingJIT()) return;
598 // First, if the main function is in the Safe module, we must add a stub to
599 // the Test module to call into it. Thus, we create a new function `main'
600 // which just calls the old one.
601 if (Function *oldMain = Safe->getNamedFunction("main"))
602 if (!oldMain->isExternal()) {
604 oldMain->setName("llvm_bugpoint_old_main");
605 // Create a NEW `main' function with same type in the test module.
606 Function *newMain = new Function(oldMain->getFunctionType(),
607 GlobalValue::ExternalLinkage,
609 // Create an `oldmain' prototype in the test module, which will
610 // corresponds to the real main function in the same module.
611 Function *oldMainProto = new Function(oldMain->getFunctionType(),
612 GlobalValue::ExternalLinkage,
613 oldMain->getName(), Test);
614 // Set up and remember the argument list for the main function.
615 std::vector<Value*> args;
616 for (Function::aiterator I = newMain->abegin(), E = newMain->aend(),
617 OI = oldMain->abegin(); I != E; ++I, ++OI) {
618 I->setName(OI->getName()); // Copy argument names from oldMain
622 // Call the old main function and return its result
623 BasicBlock *BB = new BasicBlock("entry", newMain);
624 CallInst *call = new CallInst(oldMainProto, args);
625 BB->getInstList().push_back(call);
627 // If the type of old function wasn't void, return value of call
628 new ReturnInst(oldMain->getReturnType() != Type::VoidTy ? call : 0, BB);
631 // The second nasty issue we must deal with in the JIT is that the Safe
632 // module cannot directly reference any functions defined in the test
633 // module. Instead, we use a JIT API call to dynamically resolve the
636 // Add the resolver to the Safe module.
637 // Prototype: void *getPointerToNamedFunction(const char* Name)
638 Function *resolverFunc =
639 Safe->getOrInsertFunction("getPointerToNamedFunction",
640 PointerType::get(Type::SByteTy),
641 PointerType::get(Type::SByteTy), 0);
643 // Use the function we just added to get addresses of functions we need.
644 for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) {
645 if (F->isExternal() && !F->use_empty() && &*F != resolverFunc &&
646 F->getIntrinsicID() == 0 /* ignore intrinsics */) {
647 Function *TestFn = Test->getFunction(F->getName(), F->getFunctionType());
649 // Don't forward functions which are external in the test module too.
650 if (TestFn && !TestFn->isExternal()) {
651 // 1. Add a string constant with its name to the global file
652 Constant *InitArray = ConstantArray::get(F->getName());
653 GlobalVariable *funcName =
654 new GlobalVariable(InitArray->getType(), true /*isConstant*/,
655 GlobalValue::InternalLinkage, InitArray,
656 F->getName() + "_name", Safe);
658 // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
659 // sbyte* so it matches the signature of the resolver function.
661 // GetElementPtr *funcName, ulong 0, ulong 0
662 std::vector<Constant*> GEPargs(2,Constant::getNullValue(Type::IntTy));
664 ConstantExpr::getGetElementPtr(ConstantPointerRef::get(funcName),
666 std::vector<Value*> ResolverArgs;
667 ResolverArgs.push_back(GEP);
669 // Rewrite uses of F in global initializers, etc. to uses of a wrapper
670 // function that dynamically resolves the calls to F via our JIT API
671 if (F->use_begin() != F->use_end()) {
672 // Construct a new stub function that will re-route calls to F
673 const FunctionType *FuncTy = F->getFunctionType();
674 Function *FuncWrapper = new Function(FuncTy,
675 GlobalValue::InternalLinkage,
676 F->getName() + "_wrapper",
678 BasicBlock *Header = new BasicBlock("header", FuncWrapper);
680 // Resolve the call to function F via the JIT API:
682 // call resolver(GetElementPtr...)
683 CallInst *resolve = new CallInst(resolverFunc, ResolverArgs,
685 Header->getInstList().push_back(resolve);
686 // cast the result from the resolver to correctly-typed function
687 CastInst *castResolver =
688 new CastInst(resolve, PointerType::get(F->getFunctionType()),
690 Header->getInstList().push_back(castResolver);
692 // Save the argument list
693 std::vector<Value*> Args;
694 for (Function::aiterator i = FuncWrapper->abegin(),
695 e = FuncWrapper->aend(); i != e; ++i)
698 // Pass on the arguments to the real function, return its result
699 if (F->getReturnType() == Type::VoidTy) {
700 CallInst *Call = new CallInst(castResolver, Args);
701 Header->getInstList().push_back(Call);
702 ReturnInst *Ret = new ReturnInst();
703 Header->getInstList().push_back(Ret);
705 CallInst *Call = new CallInst(castResolver, Args, "redir");
706 Header->getInstList().push_back(Call);
707 ReturnInst *Ret = new ReturnInst(Call);
708 Header->getInstList().push_back(Ret);
711 // Use the wrapper function instead of the old function
712 F->replaceAllUsesWith(FuncWrapper);
718 if (verifyModule(*Test) || verifyModule(*Safe)) {
719 std::cerr << "Bugpoint has a bug, which corrupted a module!!\n";
726 /// TestCodeGenerator - This is the predicate function used to check to see if
727 /// the "Test" portion of the program is miscompiled by the code generator under
728 /// test. If so, return true. In any case, both module arguments are deleted.
730 static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe) {
731 CleanupAndPrepareModules(BD, Test, Safe);
733 std::string TestModuleBC = getUniqueFilename("bugpoint.test.bc");
734 if (BD.writeProgramToFile(TestModuleBC, Test)) {
735 std::cerr << "Error writing bytecode to `" << TestModuleBC << "'\nExiting.";
740 // Make the shared library
741 std::string SafeModuleBC = getUniqueFilename("bugpoint.safe.bc");
743 if (BD.writeProgramToFile(SafeModuleBC, Safe)) {
744 std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting.";
747 std::string SharedObject = BD.compileSharedObject(SafeModuleBC);
750 // Run the code generator on the `Test' code, loading the shared library.
751 // The function returns whether or not the new output differs from reference.
752 int Result = BD.diffProgram(TestModuleBC, SharedObject, false);
755 std::cerr << ": still failing!\n";
757 std::cerr << ": didn't fail.\n";
758 removeFile(TestModuleBC);
759 removeFile(SafeModuleBC);
760 removeFile(SharedObject);
766 /// debugCodeGenerator - debug errors in LLC, LLI, or CBE.
768 bool BugDriver::debugCodeGenerator() {
769 if ((void*)cbe == (void*)Interpreter) {
770 std::string Result = executeProgramWithCBE("bugpoint.cbe.out");
771 std::cout << "\n*** The C backend cannot match the reference diff, but it "
772 << "is used as the 'known good'\n code generator, so I can't"
773 << " debug it. Perhaps you have a front-end problem?\n As a"
774 << " sanity check, I left the result of executing the program "
775 << "with the C backend\n in this file for you: '"
780 DisambiguateGlobalSymbols(Program);
782 std::vector<Function*> Funcs = DebugAMiscompilation(*this, TestCodeGenerator);
784 // Split the module into the two halves of the program we want.
785 Module *ToNotCodeGen = CloneModule(getProgram());
786 Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs);
788 // Condition the modules
789 CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen);
791 std::string TestModuleBC = getUniqueFilename("bugpoint.test.bc");
792 if (writeProgramToFile(TestModuleBC, ToCodeGen)) {
793 std::cerr << "Error writing bytecode to `" << TestModuleBC << "'\nExiting.";
798 // Make the shared library
799 std::string SafeModuleBC = getUniqueFilename("bugpoint.safe.bc");
800 if (writeProgramToFile(SafeModuleBC, ToNotCodeGen)) {
801 std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting.";
804 std::string SharedObject = compileSharedObject(SafeModuleBC);
807 std::cout << "You can reproduce the problem with the command line: \n";
808 if (isExecutingJIT()) {
809 std::cout << " lli -load " << SharedObject << " " << TestModuleBC;
811 std::cout << " llc " << TestModuleBC << " -o " << TestModuleBC << ".s\n";
812 std::cout << " gcc " << SharedObject << " " << TestModuleBC
813 << ".s -o " << TestModuleBC << ".exe -Wl,-R.\n";
814 std::cout << " " << TestModuleBC << ".exe";
816 for (unsigned i=0, e = InputArgv.size(); i != e; ++i)
817 std::cout << " " << InputArgv[i];
819 std::cout << "The shared object was created with:\n llc -march=c "
820 << SafeModuleBC << " -o temporary.c\n"
821 << " gcc -xc temporary.c -O2 -o " << SharedObject
822 #if defined(sparc) || defined(__sparc__) || defined(__sparcv9)
823 << " -G" // Compile a shared library, `-G' for Sparc
825 << " -shared" // `-shared' for Linux/X86, maybe others
827 << " -fno-strict-aliasing\n";