//===- Miscompilation.cpp - Debug program miscompilations -----------------===//
+//
+// The LLVM Compiler Infrastructure
//
-// This file implements program miscompilation debugging support.
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements optimizer and code generation miscompilation debugging
+// support.
//
//===----------------------------------------------------------------------===//
#include "BugDriver.h"
-#include "SystemUtils.h"
#include "ListReducer.h"
-#include "llvm/Pass.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Analysis/Verifier.h"
+#include "llvm/Support/Mangler.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/Linker.h"
#include "Support/CommandLine.h"
+#include "Support/FileUtilities.h"
+using namespace llvm;
-// Anonymous namespace to define command line options for miscompilation
-// debugging.
-//
-namespace {
- // Output - The user can specify a file containing the expected output of the
- // program. If this filename is set, it is used as the reference diff source,
- // otherwise the raw input run through an interpreter is used as the reference
- // source.
- //
- cl::opt<std::string>
- Output("output", cl::desc("Specify a reference program output "
- "(for miscompilation detection)"));
+namespace llvm {
+ extern cl::list<std::string> InputArgv;
}
-class ReduceMiscompilingPasses : public ListReducer<const PassInfo*> {
- BugDriver &BD;
-public:
- ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
-
- virtual TestResult doTest(std::vector<const PassInfo*> &Prefix,
- std::vector<const PassInfo*> &Kept);
-};
+namespace {
+ class ReduceMiscompilingPasses : public ListReducer<const PassInfo*> {
+ BugDriver &BD;
+ public:
+ ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
+
+ virtual TestResult doTest(std::vector<const PassInfo*> &Prefix,
+ std::vector<const PassInfo*> &Suffix);
+ };
+}
ReduceMiscompilingPasses::TestResult
ReduceMiscompilingPasses::doTest(std::vector<const PassInfo*> &Prefix,
std::string BytecodeResult;
if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
- std::cerr << BD.getToolName() << ": Error running this sequence of passes"
+ std::cerr << " Error running this sequence of passes"
<< " on the input program!\n";
- exit(1);
+ BD.setPassesToRun(Suffix);
+ BD.EmitProgressBytecode("pass-error", false);
+ exit(BD.debugOptimizerCrash());
}
// Check to see if the finished program matches the reference output...
- if (BD.diffProgram(Output, BytecodeResult, true /*delete bytecode*/)) {
+ if (BD.diffProgram(BytecodeResult, "", true /*delete bytecode*/)) {
std::cout << "nope.\n";
return KeepSuffix; // Miscompilation detected!
}
if (Prefix.empty()) return NoFailure;
// Next, see if the program is broken if we run the "prefix" passes first,
- // then seperately run the "kept" passes.
+ // then separately run the "kept" passes.
std::cout << "Checking to see if '" << getPassesString(Prefix)
<< "' compile correctly: ";
// prefix passes, then discard the prefix passes.
//
if (BD.runPasses(Prefix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
- std::cerr << BD.getToolName() << ": Error running this sequence of passes"
+ std::cerr << " Error running this sequence of passes"
<< " on the input program!\n";
- exit(1);
+ BD.setPassesToRun(Prefix);
+ BD.EmitProgressBytecode("pass-error", false);
+ exit(BD.debugOptimizerCrash());
}
// If the prefix maintains the predicate by itself, only keep the prefix!
- if (BD.diffProgram(Output, BytecodeResult)) {
+ if (BD.diffProgram(BytecodeResult)) {
std::cout << "nope.\n";
removeFile(BytecodeResult);
return KeepPrefix;
// Ok, so now we know that the prefix passes work, try running the suffix
// passes on the result of the prefix passes.
//
- Module *PrefixOutput = BD.ParseInputFile(BytecodeResult);
+ Module *PrefixOutput = ParseInputFile(BytecodeResult);
if (PrefixOutput == 0) {
std::cerr << BD.getToolName() << ": Error reading bytecode file '"
<< BytecodeResult << "'!\n";
<< "' passes compile correctly after the '"
<< getPassesString(Prefix) << "' passes: ";
- Module *OriginalInput = BD.Program;
- BD.Program = PrefixOutput;
+ Module *OriginalInput = BD.swapProgramIn(PrefixOutput);
if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
- std::cerr << BD.getToolName() << ": Error running this sequence of passes"
+ std::cerr << " Error running this sequence of passes"
<< " on the input program!\n";
- exit(1);
+ BD.setPassesToRun(Suffix);
+ BD.EmitProgressBytecode("pass-error", false);
+ exit(BD.debugOptimizerCrash());
}
// Run the result...
- if (BD.diffProgram(Output, BytecodeResult, true/*delete bytecode*/)) {
+ if (BD.diffProgram(BytecodeResult, "", true/*delete bytecode*/)) {
std::cout << "nope.\n";
delete OriginalInput; // We pruned down the original input...
return KeepSuffix;
// Otherwise, we must not be running the bad pass anymore.
std::cout << "yup.\n"; // No miscompilation!
- BD.Program = OriginalInput; // Restore original program
- delete PrefixOutput; // Free experiment
+ delete BD.swapProgramIn(OriginalInput); // Restore orig program & free test
return NoFailure;
}
-static void PrintFunctionList(const std::vector<Function*> &Funcs) {
- for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
- if (i) std::cout << ", ";
- std::cout << Funcs[i]->getName();
- }
+namespace {
+ class ReduceMiscompilingFunctions : public ListReducer<Function*> {
+ BugDriver &BD;
+ bool (*TestFn)(BugDriver &, Module *, Module *);
+ public:
+ ReduceMiscompilingFunctions(BugDriver &bd,
+ bool (*F)(BugDriver &, Module *, Module *))
+ : BD(bd), TestFn(F) {}
+
+ virtual TestResult doTest(std::vector<Function*> &Prefix,
+ std::vector<Function*> &Suffix) {
+ if (!Suffix.empty() && TestFuncs(Suffix))
+ return KeepSuffix;
+ if (!Prefix.empty() && TestFuncs(Prefix))
+ return KeepPrefix;
+ return NoFailure;
+ }
+
+ bool TestFuncs(const std::vector<Function*> &Prefix);
+ };
}
+/// TestMergedProgram - Given two modules, link them together and run the
+/// program, checking to see if the program matches the diff. If the diff
+/// matches, return false, otherwise return true. If the DeleteInputs argument
+/// is set to true then this function deletes both input modules before it
+/// returns.
+static bool TestMergedProgram(BugDriver &BD, Module *M1, Module *M2,
+ bool DeleteInputs) {
+ // Link the two portions of the program back to together.
+ std::string ErrorMsg;
+ if (!DeleteInputs) M1 = CloneModule(M1);
+ if (LinkModules(M1, M2, &ErrorMsg)) {
+ std::cerr << BD.getToolName() << ": Error linking modules together:"
+ << ErrorMsg << "\n";
+ exit(1);
+ }
+ if (DeleteInputs) delete M2; // We are done with this module...
-class ReduceMiscompilingFunctions : public ListReducer<Function*> {
- BugDriver &BD;
-public:
- ReduceMiscompilingFunctions(BugDriver &bd) : BD(bd) {}
+ Module *OldProgram = BD.swapProgramIn(M1);
- virtual TestResult doTest(std::vector<Function*> &Prefix,
- std::vector<Function*> &Suffix) {
- if (TestFuncs(Suffix, false))
- return KeepSuffix;
- if (!Prefix.empty() && TestFuncs(Prefix, false))
- return KeepPrefix;
- return NoFailure;
- }
-
- bool TestFuncs(const std::vector<Function*> &Prefix, bool EmitBytecode);
-};
+ // Execute the program. If it does not match the expected output, we must
+ // return true.
+ bool Broken = BD.diffProgram();
-bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs,
- bool EmitBytecode) {
+ // Delete the linked module & restore the original
+ BD.swapProgramIn(OldProgram);
+ delete M1;
+ return Broken;
+}
+
+bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*>&Funcs){
// Test to see if the function is misoptimized if we ONLY run it on the
// functions listed in Funcs.
- if (!EmitBytecode) {
- std::cout << "Checking to see if the program is misoptimized when these "
- << "functions are run\nthrough the passes: ";
- PrintFunctionList(Funcs);
- std::cout << "\n";
- } else {
- std::cout <<"Outputting reduced bytecode files which expose the problem:\n";
- }
+ std::cout << "Checking to see if the program is misoptimized when "
+ << (Funcs.size()==1 ? "this function is" : "these functions are")
+ << " run through the pass"
+ << (BD.getPassesToRun().size() == 1 ? "" : "es") << ":";
+ PrintFunctionList(Funcs);
+ std::cout << "\n";
- // First step: clone the module for the two halves of the program we want.
- Module *ToOptimize = CloneModule(BD.Program);
-
- // Second step: Make sure functions & globals are all external so that linkage
- // between the two modules will work.
- for (Module::iterator I = ToOptimize->begin(), E = ToOptimize->end();I!=E;++I)
- I->setLinkage(GlobalValue::ExternalLinkage);
- for (Module::giterator I = ToOptimize->gbegin(), E = ToOptimize->gend();
- I != E; ++I)
- I->setLinkage(GlobalValue::ExternalLinkage);
-
- // Third step: make a clone of the externalized program for the non-optimized
- // part.
- Module *ToNotOptimize = CloneModule(ToOptimize);
-
- // Fourth step: Remove the test functions from the ToNotOptimize module, and
- // all of the global variables.
- for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
- Function *TNOF = ToNotOptimize->getFunction(Funcs[i]->getName(),
- Funcs[i]->getFunctionType());
- assert(TNOF && "Function doesn't exist in module!");
- DeleteFunctionBody(TNOF); // Function is now external in this module!
- }
- for (Module::giterator I = ToNotOptimize->gbegin(), E = ToNotOptimize->gend();
- I != E; ++I)
- I->setInitializer(0); // Delete the initializer to make it external
-
- if (EmitBytecode) {
- std::cout << " Non-optimized portion: ";
- std::swap(BD.Program, ToNotOptimize);
- BD.EmitProgressBytecode("tonotoptimize", true);
- std::swap(BD.Program, ToNotOptimize);
- }
+ // Split the module into the two halves of the program we want.
+ Module *ToNotOptimize = CloneModule(BD.getProgram());
+ Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, Funcs);
- // Fifth step: Remove all functions from the ToOptimize module EXCEPT for the
- // ones specified in Funcs. We know which ones these are because they are
- // non-external in ToOptimize, but external in ToNotOptimize.
- //
- for (Module::iterator I = ToOptimize->begin(), E = ToOptimize->end();I!=E;++I)
- if (!I->isExternal()) {
- Function *TNOF = ToNotOptimize->getFunction(I->getName(),
- I->getFunctionType());
- assert(TNOF && "Function doesn't exist in ToNotOptimize module??");
- if (!TNOF->isExternal())
- DeleteFunctionBody(I);
+ // Run the predicate, not that the predicate will delete both input modules.
+ return TestFn(BD, ToOptimize, ToNotOptimize);
+}
+
+static void DisambiguateGlobalSymbols(Module *M) {
+ // Try not to cause collisions by minimizing chances of renaming an
+ // already-external symbol, so take in external globals and functions as-is.
+ // The code should work correctly without disambiguation (assuming the same
+ // mangler is used by the two code generators), but having symbols with the
+ // same name causes warnings to be emitted by the code generator.
+ Mangler Mang(*M);
+ for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
+ I->setName(Mang.getValueName(I));
+ for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
+ I->setName(Mang.getValueName(I));
+}
+
+/// ExtractLoops - Given a reduced list of functions that still exposed the bug,
+/// check to see if we can extract the loops in the region without obscuring the
+/// bug. If so, it reduces the amount of code identified.
+static bool ExtractLoops(BugDriver &BD,
+ bool (*TestFn)(BugDriver &, Module *, Module *),
+ std::vector<Function*> &MiscompiledFunctions) {
+ bool MadeChange = false;
+ while (1) {
+ Module *ToNotOptimize = CloneModule(BD.getProgram());
+ Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
+ MiscompiledFunctions);
+ Module *ToOptimizeLoopExtracted = BD.ExtractLoop(ToOptimize);
+ if (!ToOptimizeLoopExtracted) {
+ // If the loop extractor crashed or if there were no extractible loops,
+ // then this chapter of our odyssey is over with.
+ delete ToNotOptimize;
+ delete ToOptimize;
+ return MadeChange;
}
- if (EmitBytecode) {
- std::cout << " Portion that is input to optimizer: ";
- std::swap(BD.Program, ToOptimize);
- BD.EmitProgressBytecode("tooptimize");
- std::swap(BD.Program, ToOptimize);
- }
+ std::cerr << "Extracted a loop from the breaking portion of the program.\n";
+ delete ToOptimize;
+
+ // Bugpoint is intentionally not very trusting of LLVM transformations. In
+ // particular, we're not going to assume that the loop extractor works, so
+ // we're going to test the newly loop extracted program to make sure nothing
+ // has broken. If something broke, then we'll inform the user and stop
+ // extraction.
+ AbstractInterpreter *AI = BD.switchToCBE();
+ if (TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize, false)) {
+ BD.switchToInterpreter(AI);
+
+ // Merged program doesn't work anymore!
+ std::cerr << " *** ERROR: Loop extraction broke the program. :("
+ << " Please report a bug!\n";
+ std::cerr << " Continuing on with un-loop-extracted version.\n";
+ delete ToNotOptimize;
+ delete ToOptimizeLoopExtracted;
+ return MadeChange;
+ }
+ BD.switchToInterpreter(AI);
+
+ std::cout << " Testing after loop extraction:\n";
+ // Clone modules, the tester function will free them.
+ Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted);
+ Module *TNOBackup = CloneModule(ToNotOptimize);
+ if (!TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize)) {
+ std::cout << "*** Loop extraction masked the problem. Undoing.\n";
+ // If the program is not still broken, then loop extraction did something
+ // that masked the error. Stop loop extraction now.
+ delete TOLEBackup;
+ delete TNOBackup;
+ return MadeChange;
+ }
+ ToOptimizeLoopExtracted = TOLEBackup;
+ ToNotOptimize = TNOBackup;
+
+ std::cout << "*** Loop extraction successful!\n";
+
+ // Okay, great! Now we know that we extracted a loop and that loop
+ // extraction both didn't break the program, and didn't mask the problem.
+ // Replace the current program with the loop extracted version, and try to
+ // extract another loop.
+ std::string ErrorMsg;
+ if (LinkModules(ToNotOptimize, ToOptimizeLoopExtracted, &ErrorMsg)) {
+ std::cerr << BD.getToolName() << ": Error linking modules together:"
+ << ErrorMsg << "\n";
+ exit(1);
+ }
- // Sixth step: Run the optimization passes on ToOptimize, producing a
- // transformed version of the functions being tested.
- Module *OldProgram = BD.Program;
- BD.Program = ToOptimize;
+ // All of the Function*'s in the MiscompiledFunctions list are in the old
+ // module. Update this list to include all of the functions in the
+ // optimized and loop extracted module.
+ MiscompiledFunctions.clear();
+ for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
+ E = ToOptimizeLoopExtracted->end(); I != E; ++I) {
+ if (!I->isExternal()) {
+ Function *NewF = ToNotOptimize->getFunction(I->getName(),
+ I->getFunctionType());
+ assert(NewF && "Function not found??");
+ MiscompiledFunctions.push_back(NewF);
+ }
+ }
+ delete ToOptimizeLoopExtracted;
- if (!EmitBytecode)
- std::cout << " Optimizing functions being tested: ";
- std::string BytecodeResult;
- if (BD.runPasses(BD.PassesToRun, BytecodeResult, false/*delete*/,
- true/*quiet*/)) {
- std::cerr << BD.getToolName() << ": Error running this sequence of passes"
- << " on the input program!\n";
- exit(1);
+ BD.setNewProgram(ToNotOptimize);
+ MadeChange = true;
}
+}
- if (!EmitBytecode)
- std::cout << "done.\n";
+/// DebugAMiscompilation - This is a generic driver to narrow down
+/// miscompilations, either in an optimization or a code generator.
+static std::vector<Function*>
+DebugAMiscompilation(BugDriver &BD,
+ bool (*TestFn)(BugDriver &, Module *, Module *)) {
+ // Okay, now that we have reduced the list of passes which are causing the
+ // failure, see if we can pin down which functions are being
+ // miscompiled... first build a list of all of the non-external functions in
+ // the program.
+ std::vector<Function*> MiscompiledFunctions;
+ Module *Prog = BD.getProgram();
+ for (Module::iterator I = Prog->begin(), E = Prog->end(); I != E; ++I)
+ if (!I->isExternal())
+ MiscompiledFunctions.push_back(I);
- delete BD.Program; // Delete the old "ToOptimize" module
- BD.Program = BD.ParseInputFile(BytecodeResult);
+ // Do the reduction...
+ ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
- if (EmitBytecode) {
- std::cout << " 'tooptimize' after being optimized: ";
- BD.EmitProgressBytecode("optimized", true);
- }
+ std::cout << "\n*** The following function"
+ << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
+ << " being miscompiled: ";
+ PrintFunctionList(MiscompiledFunctions);
+ std::cout << "\n";
- if (BD.Program == 0) {
- std::cerr << BD.getToolName() << ": Error reading bytecode file '"
- << BytecodeResult << "'!\n";
- exit(1);
- }
- removeFile(BytecodeResult); // No longer need the file on disk
+ // See if we can rip any loops out of the miscompiled functions and still
+ // trigger the problem.
+ if (ExtractLoops(BD, TestFn, MiscompiledFunctions)) {
+ // Okay, we extracted some loops and the problem still appears. See if we
+ // can eliminate some of the created functions from being candidates.
- // Seventh step: Link the optimized part of the program back to the
- // unoptimized part of the program.
- //
- if (LinkModules(BD.Program, ToNotOptimize, &BytecodeResult)) {
- std::cerr << BD.getToolName() << ": Error linking modules together:"
- << BytecodeResult << "\n";
- exit(1);
- }
- delete ToNotOptimize; // We are done with this module...
-
- if (EmitBytecode) {
- std::cout << " Program as tested: ";
- BD.EmitProgressBytecode("linked", true);
- delete BD.Program;
- BD.Program = OldProgram;
- return false; // We don't need to actually execute the program here.
- }
+ // Loop extraction can introduce functions with the same name (foo_code).
+ // Make sure to disambiguate the symbols so that when the program is split
+ // apart that we can link it back together again.
+ DisambiguateGlobalSymbols(BD.getProgram());
- std::cout << " Checking to see if the merged program executes correctly: ";
+ // Do the reduction...
+ ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
+
+ std::cout << "\n*** The following function"
+ << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
+ << " being miscompiled: ";
+ PrintFunctionList(MiscompiledFunctions);
+ std::cout << "\n";
+ }
- // Eighth step: Execute the program. If it does not match the expected
- // output, then 'Funcs' are being misoptimized!
- bool Broken = BD.diffProgram(Output);
+ return MiscompiledFunctions;
+}
- delete BD.Program; // Delete the hacked up program
- BD.Program = OldProgram; // Restore the original
+/// TestOptimizer - This is the predicate function used to check to see if the
+/// "Test" portion of the program is misoptimized. If so, return true. In any
+/// case, both module arguments are deleted.
+static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe) {
+ // Run the optimization passes on ToOptimize, producing a transformed version
+ // of the functions being tested.
+ std::cout << " Optimizing functions being tested: ";
+ Module *Optimized = BD.runPassesOn(Test, BD.getPassesToRun(),
+ /*AutoDebugCrashes*/true);
+ std::cout << "done.\n";
+ delete Test;
- std::cout << (Broken ? "nope.\n" : "yup.\n");
+ std::cout << " Checking to see if the merged program executes correctly: ";
+ bool Broken = TestMergedProgram(BD, Optimized, Safe, true);
+ std::cout << (Broken ? " nope.\n" : " yup.\n");
return Broken;
}
/// input.
///
bool BugDriver::debugMiscompilation() {
- std::cout << "*** Debugging miscompilation!\n";
-
- // Set up the execution environment, selecting a method to run LLVM bytecode.
- if (initializeExecutionEnvironment()) return true;
-
- // Run the raw input to see where we are coming from. If a reference output
- // was specified, make sure that the raw output matches it. If not, it's a
- // problem in the front-end or whatever produced the input code.
- //
- bool CreatedOutput = false;
- if (Output.empty()) {
- std::cout << "Generating reference output from raw program...";
- Output = executeProgram("bugpoint.reference.out");
- CreatedOutput = true;
- std::cout << " done! Reference output is: " << Output << "\n";
- } else if (diffProgram(Output)) {
- std::cout << "\n*** Input program does not match reference diff!\n"
- << " Must be problem with input source!\n";
- return false; // Problem found
- }
-
- // Figure out which transformations miscompile the input program.
- unsigned OldSize = PassesToRun.size();
- ReduceMiscompilingPasses(*this).reduceList(PassesToRun);
-
// Make sure something was miscompiled...
- if (PassesToRun.size() == OldSize) {
+ if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun)) {
std::cerr << "*** Optimized program matches reference output! No problem "
<< "detected...\nbugpoint can't help you with your problem!\n";
return false;
}
std::cout << "\n*** Found miscompiling pass"
- << (PassesToRun.size() == 1 ? "" : "es") << ": "
- << getPassesString(PassesToRun) << "\n";
+ << (getPassesToRun().size() == 1 ? "" : "es") << ": "
+ << getPassesString(getPassesToRun()) << "\n";
EmitProgressBytecode("passinput");
+ std::vector<Function*> MiscompiledFunctions =
+ DebugAMiscompilation(*this, TestOptimizer);
- // Okay, now that we have reduced the list of passes which are causing the
- // failure, see if we can pin down which functions are being
- // miscompiled... first build a list of all of the non-external functions in
- // the program.
- std::vector<Function*> MiscompiledFunctions;
- for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
- if (!I->isExternal())
- MiscompiledFunctions.push_back(I);
+ // Output a bunch of bytecode files for the user...
+ std::cout << "Outputting reduced bytecode files which expose the problem:\n";
+ Module *ToNotOptimize = CloneModule(getProgram());
+ Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
+ MiscompiledFunctions);
+
+ std::cout << " Non-optimized portion: ";
+ ToNotOptimize = swapProgramIn(ToNotOptimize);
+ EmitProgressBytecode("tonotoptimize", true);
+ setNewProgram(ToNotOptimize); // Delete hacked module.
+
+ std::cout << " Portion that is input to optimizer: ";
+ ToOptimize = swapProgramIn(ToOptimize);
+ EmitProgressBytecode("tooptimize");
+ setNewProgram(ToOptimize); // Delete hacked module.
- // Do the reduction...
- ReduceMiscompilingFunctions(*this).reduceList(MiscompiledFunctions);
+ return false;
+}
- std::cout << "\n*** The following functions are being miscompiled: ";
- PrintFunctionList(MiscompiledFunctions);
- std::cout << "\n";
+/// CleanupAndPrepareModules - Get the specified modules ready for code
+/// generator testing.
+static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
+ Module *Safe) {
+ // Clean up the modules, removing extra cruft that we don't need anymore...
+ Test = BD.performFinalCleanups(Test);
+
+ // If we are executing the JIT, we have several nasty issues to take care of.
+ if (!BD.isExecutingJIT()) return;
+
+ // First, if the main function is in the Safe module, we must add a stub to
+ // the Test module to call into it. Thus, we create a new function `main'
+ // which just calls the old one.
+ if (Function *oldMain = Safe->getNamedFunction("main"))
+ if (!oldMain->isExternal()) {
+ // Rename it
+ oldMain->setName("llvm_bugpoint_old_main");
+ // Create a NEW `main' function with same type in the test module.
+ Function *newMain = new Function(oldMain->getFunctionType(),
+ GlobalValue::ExternalLinkage,
+ "main", Test);
+ // Create an `oldmain' prototype in the test module, which will
+ // corresponds to the real main function in the same module.
+ Function *oldMainProto = new Function(oldMain->getFunctionType(),
+ GlobalValue::ExternalLinkage,
+ oldMain->getName(), Test);
+ // Set up and remember the argument list for the main function.
+ std::vector<Value*> args;
+ for (Function::aiterator I = newMain->abegin(), E = newMain->aend(),
+ OI = oldMain->abegin(); I != E; ++I, ++OI) {
+ I->setName(OI->getName()); // Copy argument names from oldMain
+ args.push_back(I);
+ }
+
+ // Call the old main function and return its result
+ BasicBlock *BB = new BasicBlock("entry", newMain);
+ CallInst *call = new CallInst(oldMainProto, args);
+ BB->getInstList().push_back(call);
+
+ // If the type of old function wasn't void, return value of call
+ new ReturnInst(oldMain->getReturnType() != Type::VoidTy ? call : 0, BB);
+ }
- // Output a bunch of bytecode files for the user...
- ReduceMiscompilingFunctions(*this).TestFuncs(MiscompiledFunctions, true);
+ // The second nasty issue we must deal with in the JIT is that the Safe
+ // module cannot directly reference any functions defined in the test
+ // module. Instead, we use a JIT API call to dynamically resolve the
+ // symbol.
+
+ // Add the resolver to the Safe module.
+ // Prototype: void *getPointerToNamedFunction(const char* Name)
+ Function *resolverFunc =
+ Safe->getOrInsertFunction("getPointerToNamedFunction",
+ PointerType::get(Type::SByteTy),
+ PointerType::get(Type::SByteTy), 0);
+
+ // Use the function we just added to get addresses of functions we need.
+ for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F){
+ if (F->isExternal() && !F->use_empty() && &*F != resolverFunc &&
+ F->getIntrinsicID() == 0 /* ignore intrinsics */) {
+ Function *TestFn =Test->getFunction(F->getName(), F->getFunctionType());
+
+ // Don't forward functions which are external in the test module too.
+ if (TestFn && !TestFn->isExternal()) {
+ // 1. Add a string constant with its name to the global file
+ Constant *InitArray = ConstantArray::get(F->getName());
+ GlobalVariable *funcName =
+ new GlobalVariable(InitArray->getType(), true /*isConstant*/,
+ GlobalValue::InternalLinkage, InitArray,
+ F->getName() + "_name", Safe);
+
+ // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
+ // sbyte* so it matches the signature of the resolver function.
+
+ // GetElementPtr *funcName, ulong 0, ulong 0
+ std::vector<Constant*> GEPargs(2,Constant::getNullValue(Type::IntTy));
+ Value *GEP =
+ ConstantExpr::getGetElementPtr(ConstantPointerRef::get(funcName),
+ GEPargs);
+ std::vector<Value*> ResolverArgs;
+ ResolverArgs.push_back(GEP);
+
+ // 3. Replace all uses of `func' with calls to resolver by:
+ // (a) Iterating through the list of uses of this function
+ // (b) Insert a cast instruction in front of each use
+ // (c) Replace use of old call with new call
+
+ // Insert code at the beginning of the function
+ while (!F->use_empty())
+ if (Instruction *Inst = dyn_cast<Instruction>(F->use_back())) {
+ // call resolver(GetElementPtr...)
+ CallInst *resolve = new CallInst(resolverFunc, ResolverArgs,
+ "resolver", Inst);
+ // cast the result from the resolver to correctly-typed function
+ CastInst *castResolver =
+ new CastInst(resolve, PointerType::get(F->getFunctionType()),
+ "resolverCast", Inst);
+ // actually use the resolved function
+ Inst->replaceUsesOfWith(F, castResolver);
+ } else {
+ // FIXME: need to take care of cases where a function is used by
+ // something other than an instruction; e.g., global variable
+ // initializers and constant expressions.
+ std::cerr << "UNSUPPORTED: Non-instruction is using an external "
+ << "function, " << F->getName() << "().\n";
+ abort();
+ }
+ }
+ }
+ }
+
+ if (verifyModule(*Test) || verifyModule(*Safe)) {
+ std::cerr << "Bugpoint has a bug, which corrupted a module!!\n";
+ abort();
+ }
+}
+
+
+
+/// TestCodeGenerator - This is the predicate function used to check to see if
+/// the "Test" portion of the program is miscompiled by the code generator under
+/// test. If so, return true. In any case, both module arguments are deleted.
+static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe) {
+ CleanupAndPrepareModules(BD, Test, Safe);
+
+ std::string TestModuleBC = getUniqueFilename("bugpoint.test.bc");
+ if (BD.writeProgramToFile(TestModuleBC, Test)) {
+ std::cerr << "Error writing bytecode to `" << TestModuleBC << "'\nExiting.";
+ exit(1);
+ }
+ delete Test;
+
+ // Make the shared library
+ std::string SafeModuleBC = getUniqueFilename("bugpoint.safe.bc");
+
+ if (BD.writeProgramToFile(SafeModuleBC, Safe)) {
+ std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting.";
+ exit(1);
+ }
+ std::string SharedObject = BD.compileSharedObject(SafeModuleBC);
+ delete Safe;
+
+ // Run the code generator on the `Test' code, loading the shared library.
+ // The function returns whether or not the new output differs from reference.
+ int Result = BD.diffProgram(TestModuleBC, SharedObject, false);
+
+ if (Result)
+ std::cerr << ": still failing!\n";
+ else
+ std::cerr << ": didn't fail.\n";
+ removeFile(TestModuleBC);
+ removeFile(SafeModuleBC);
+ removeFile(SharedObject);
+
+ return Result;
+}
+
+
+bool BugDriver::debugCodeGenerator() {
+ if ((void*)cbe == (void*)Interpreter) {
+ std::string Result = executeProgramWithCBE("bugpoint.cbe.out");
+ std::cout << "\n*** The C backend cannot match the reference diff, but it "
+ << "is used as the 'known good'\n code generator, so I can't"
+ << " debug it. Perhaps you have a front-end problem?\n As a"
+ << " sanity check, I left the result of executing the program "
+ << "with the C backend\n in this file for you: '"
+ << Result << "'.\n";
+ return true;
+ }
+
+ DisambiguateGlobalSymbols(Program);
+
+ std::vector<Function*> Funcs = DebugAMiscompilation(*this, TestCodeGenerator);
+
+ // Split the module into the two halves of the program we want.
+ Module *ToNotCodeGen = CloneModule(getProgram());
+ Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs);
+
+ // Condition the modules
+ CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen);
+
+ std::string TestModuleBC = getUniqueFilename("bugpoint.test.bc");
+ if (writeProgramToFile(TestModuleBC, ToCodeGen)) {
+ std::cerr << "Error writing bytecode to `" << TestModuleBC << "'\nExiting.";
+ exit(1);
+ }
+ delete ToCodeGen;
+
+ // Make the shared library
+ std::string SafeModuleBC = getUniqueFilename("bugpoint.safe.bc");
+ if (writeProgramToFile(SafeModuleBC, ToNotCodeGen)) {
+ std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting.";
+ exit(1);
+ }
+ std::string SharedObject = compileSharedObject(SafeModuleBC);
+ delete ToNotCodeGen;
+
+ std::cout << "You can reproduce the problem with the command line: \n";
+ if (isExecutingJIT()) {
+ std::cout << " lli -load " << SharedObject << " " << TestModuleBC;
+ } else {
+ std::cout << " llc " << TestModuleBC << " -o " << TestModuleBC << ".s\n";
+ std::cout << " gcc " << SharedObject << " " << TestModuleBC
+ << ".s -o " << TestModuleBC << ".exe -Wl,-R.\n";
+ std::cout << " " << TestModuleBC << ".exe";
+ }
+ for (unsigned i=0, e = InputArgv.size(); i != e; ++i)
+ std::cout << " " << InputArgv[i];
+ std::cout << "\n";
+ std::cout << "The shared object was created with:\n llc -march=c "
+ << SafeModuleBC << " -o temporary.c\n"
+ << " gcc -xc temporary.c -O2 -o " << SharedObject
+#if defined(sparc) || defined(__sparc__) || defined(__sparcv9)
+ << " -G" // Compile a shared library, `-G' for Sparc
+#else
+ << " -shared" // `-shared' for Linux/X86, maybe others
+#endif
+ << " -fno-strict-aliasing\n";
- if (CreatedOutput) removeFile(Output);
return false;
}
projects / oota-llvm.git / blobdiff