//===- 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 "llvm/Pass.h"
+#include "ListReducer.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
#include "llvm/Module.h"
-#include "Support/CommandLine.h"
+#include "llvm/Pass.h"
+#include "llvm/Analysis/Verifier.h"
+#include "llvm/Support/Mangler.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Support/Linker.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FileUtilities.h"
+using namespace llvm;
+
+namespace llvm {
+ extern cl::list<std::string> InputArgv;
+}
-// 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)"));
+ 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);
+ };
}
-/// debugMiscompilation - This method is used when the passes selected are not
-/// crashing, but the generated output is semantically different from the
-/// input.
+/// TestResult - After passes have been split into a test group and a control
+/// group, see if they still break the program.
///
-bool BugDriver::debugMiscompilation() {
- std::cout << "*** Debugging miscompilation!\n";
+ReduceMiscompilingPasses::TestResult
+ReduceMiscompilingPasses::doTest(std::vector<const PassInfo*> &Prefix,
+ std::vector<const PassInfo*> &Suffix) {
+ // First, run the program with just the Suffix passes. If it is still broken
+ // with JUST the kept passes, discard the prefix passes.
+ std::cout << "Checking to see if '" << getPassesString(Suffix)
+ << "' compile correctly: ";
+
+ std::string BytecodeResult;
+ if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
+ std::cerr << " Error running this sequence of passes"
+ << " on the input program!\n";
+ 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(BytecodeResult, "", true /*delete bytecode*/)) {
+ std::cout << " nope.\n";
+ return KeepSuffix; // Miscompilation detected!
+ }
+ std::cout << " yup.\n"; // No miscompilation!
- // Set up the execution environment, selecting a method to run LLVM bytecode.
- if (initializeExecutionEnvironment()) return true;
+ if (Prefix.empty()) return NoFailure;
- // 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.
+ // Next, see if the program is broken if we run the "prefix" passes first,
+ // then separately run the "kept" passes.
+ std::cout << "Checking to see if '" << getPassesString(Prefix)
+ << "' compile correctly: ";
+
+ // If it is not broken with the kept passes, it's possible that the prefix
+ // passes must be run before the kept passes to break it. If the program
+ // WORKS after the prefix passes, but then fails if running the prefix AND
+ // kept passes, we can update our bytecode file to include the result of the
+ // prefix passes, then discard the prefix passes.
//
- 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: bugpoint.reference.out.\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 transformation is the first to miscompile the input
- // program. We do a binary search here in case there are a large number of
- // passes involved.
+ if (BD.runPasses(Prefix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
+ std::cerr << " Error running this sequence of passes"
+ << " on the input program!\n";
+ 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(BytecodeResult)) {
+ std::cout << " nope.\n";
+ removeFile(BytecodeResult);
+ return KeepPrefix;
+ }
+ std::cout << " yup.\n"; // No miscompilation!
+
+ // Ok, so now we know that the prefix passes work, try running the suffix
+ // passes on the result of the prefix passes.
//
- unsigned LastGood = 0, LastBad = PassesToRun.size();
- while (LastGood != LastBad) {
- unsigned Mid = (LastBad+LastGood+1) / 2;
- std::vector<const PassInfo*> P(PassesToRun.begin(),
- PassesToRun.begin()+Mid);
- std::cout << "Checking to see if the first " << Mid << " passes are ok: ";
-
- std::string BytecodeResult;
- if (runPasses(P, BytecodeResult, false, true)) {
- std::cerr << ToolName << ": Error running this sequence of passes"
- << " on the input program!\n";
+ Module *PrefixOutput = ParseInputFile(BytecodeResult);
+ if (PrefixOutput == 0) {
+ std::cerr << BD.getToolName() << ": Error reading bytecode file '"
+ << BytecodeResult << "'!\n";
+ exit(1);
+ }
+ removeFile(BytecodeResult); // No longer need the file on disk
+
+ // Don't check if there are no passes in the suffix.
+ if (Suffix.empty())
+ return NoFailure;
+
+ std::cout << "Checking to see if '" << getPassesString(Suffix)
+ << "' passes compile correctly after the '"
+ << getPassesString(Prefix) << "' passes: ";
+
+ Module *OriginalInput = BD.swapProgramIn(PrefixOutput);
+ if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
+ std::cerr << " Error running this sequence of passes"
+ << " on the input program!\n";
+ BD.setPassesToRun(Suffix);
+ BD.EmitProgressBytecode("pass-error", false);
+ exit(BD.debugOptimizerCrash());
+ }
+
+ // Run the result...
+ 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!
+ delete BD.swapProgramIn(OriginalInput); // Restore orig program & free test
+ return NoFailure;
+}
+
+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...
+
+ Module *OldProgram = BD.swapProgramIn(M1);
+
+ // Execute the program. If it does not match the expected output, we must
+ // return true.
+ bool Broken = BD.diffProgram();
+
+ // Delete the linked module & restore the original
+ BD.swapProgramIn(OldProgram);
+ delete M1;
+ return Broken;
+}
+
+/// TestFuncs - split functions in a Module into two groups: those that are
+/// under consideration for miscompilation vs. those that are not, and test
+/// accordingly. Each group of functions becomes a separate Module.
+///
+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.
+ 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';
+
+ // Split the module into the two halves of the program we want.
+ Module *ToNotOptimize = CloneModule(BD.getProgram());
+ Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, Funcs);
+
+ // Run the predicate, not that the predicate will delete both input modules.
+ return TestFn(BD, ToOptimize, ToNotOptimize);
+}
+
+/// DisambiguateGlobalSymbols - Mangle symbols to guarantee uniqueness by
+/// modifying predominantly internal symbols rather than external ones.
+///
+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;
+ }
+
+ 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);
}
- // Check to see if the finished program matches the reference output...
- if (diffProgram(Output, BytecodeResult)) {
- std::cout << "nope.\n";
- LastBad = Mid-1; // Miscompilation detected!
- } else {
- std::cout << "yup.\n";
- LastGood = Mid; // No miscompilation!
+ // 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;
- // We are now done with the optimized output... so remove it.
- removeFile(BytecodeResult);
+ BD.setNewProgram(ToNotOptimize);
+ MadeChange = true;
+ }
+}
+
+namespace {
+ class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> {
+ BugDriver &BD;
+ bool (*TestFn)(BugDriver &, Module *, Module *);
+ std::vector<Function*> FunctionsBeingTested;
+ public:
+ ReduceMiscompiledBlocks(BugDriver &bd,
+ bool (*F)(BugDriver &, Module *, Module *),
+ const std::vector<Function*> &Fns)
+ : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {}
+
+ virtual TestResult doTest(std::vector<BasicBlock*> &Prefix,
+ std::vector<BasicBlock*> &Suffix) {
+ if (!Suffix.empty() && TestFuncs(Suffix))
+ return KeepSuffix;
+ if (TestFuncs(Prefix))
+ return KeepPrefix;
+ return NoFailure;
+ }
+
+ bool TestFuncs(const std::vector<BasicBlock*> &Prefix);
+ };
+}
+
+/// TestFuncs - Extract all blocks for the miscompiled functions except for the
+/// specified blocks. If the problem still exists, return true.
+///
+bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs) {
+ // Test to see if the function is misoptimized if we ONLY run it on the
+ // functions listed in Funcs.
+ std::cout << "Checking to see if the program is misoptimized when all ";
+ if (!BBs.empty()) {
+ std::cout << "but these " << BBs.size() << " blocks are extracted: ";
+ for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i)
+ std::cout << BBs[i]->getName() << " ";
+ if (BBs.size() > 10) std::cout << "...";
+ } else {
+ std::cout << "blocks are extracted.";
+ }
+ std::cout << '\n';
+
+ // Split the module into the two halves of the program we want.
+ Module *ToNotOptimize = CloneModule(BD.getProgram());
+ Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
+ FunctionsBeingTested);
+
+ // Try the extraction. If it doesn't work, then the block extractor crashed
+ // or something, in which case bugpoint can't chase down this possibility.
+ if (Module *New = BD.ExtractMappedBlocksFromModule(BBs, ToOptimize)) {
+ delete ToOptimize;
+ // Run the predicate, not that the predicate will delete both input modules.
+ return TestFn(BD, New, ToNotOptimize);
+ }
+ delete ToOptimize;
+ delete ToNotOptimize;
+ return false;
+}
+
+
+/// ExtractBlocks - Given a reduced list of functions that still expose the bug,
+/// extract as many basic blocks from the region as possible without obscuring
+/// the bug.
+///
+static bool ExtractBlocks(BugDriver &BD,
+ bool (*TestFn)(BugDriver &, Module *, Module *),
+ std::vector<Function*> &MiscompiledFunctions) {
+ std::vector<BasicBlock*> Blocks;
+ for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
+ for (Function::iterator I = MiscompiledFunctions[i]->begin(),
+ E = MiscompiledFunctions[i]->end(); I != E; ++I)
+ Blocks.push_back(I);
+
+ // Use the list reducer to identify blocks that can be extracted without
+ // obscuring the bug. The Blocks list will end up containing blocks that must
+ // be retained from the original program.
+ unsigned OldSize = Blocks.size();
+
+ // Check to see if all blocks are extractible first.
+ if (ReduceMiscompiledBlocks(BD, TestFn,
+ MiscompiledFunctions).TestFuncs(std::vector<BasicBlock*>())) {
+ Blocks.clear();
+ } else {
+ ReduceMiscompiledBlocks(BD, TestFn,MiscompiledFunctions).reduceList(Blocks);
+ if (Blocks.size() == OldSize)
+ return false;
+ }
+
+ Module *ProgClone = CloneModule(BD.getProgram());
+ Module *ToExtract = SplitFunctionsOutOfModule(ProgClone,
+ MiscompiledFunctions);
+ Module *Extracted = BD.ExtractMappedBlocksFromModule(Blocks, ToExtract);
+ if (Extracted == 0) {
+ // Wierd, extraction should have worked.
+ std::cerr << "Nondeterministic problem extracting blocks??\n";
+ delete ProgClone;
+ delete ToExtract;
+ return false;
+ }
+
+ // Otherwise, block extraction succeeded. Link the two program fragments back
+ // together.
+ delete ToExtract;
+
+ std::string ErrorMsg;
+ if (LinkModules(ProgClone, Extracted, &ErrorMsg)) {
+ std::cerr << BD.getToolName() << ": Error linking modules together:"
+ << ErrorMsg << '\n';
+ exit(1);
+ }
+
+ // Set the new program and delete the old one.
+ BD.setNewProgram(ProgClone);
+
+ // Update the list of miscompiled functions.
+ MiscompiledFunctions.clear();
+
+ for (Module::iterator I = Extracted->begin(), E = Extracted->end(); I != E;
+ ++I)
+ if (!I->isExternal()) {
+ Function *NF = ProgClone->getFunction(I->getName(), I->getFunctionType());
+ assert(NF && "Mapped function not found!");
+ MiscompiledFunctions.push_back(NF);
+ }
+
+ delete Extracted;
+
+ return true;
+}
+
+
+/// 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);
+
+ // 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';
+
+ // 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.
+
+ // 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());
+
+ // 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';
}
+ if (ExtractBlocks(BD, TestFn, MiscompiledFunctions)) {
+ // Okay, we extracted some blocks and the problem still appears. See if we
+ // can eliminate some of the created functions from being candidates.
+
+ // Block 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());
+
+ // 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';
+ }
+
+ return MiscompiledFunctions;
+}
+
+/// 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 << " 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;
+}
+
+
+/// debugMiscompilation - This method is used when the passes selected are not
+/// crashing, but the generated output is semantically different from the
+/// input.
+///
+bool BugDriver::debugMiscompilation() {
// Make sure something was miscompiled...
- if (LastBad >= PassesToRun.size()) {
+ 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;
}
- // Calculate which pass it is that miscompiles...
- const PassInfo *ThePass = PassesToRun[LastBad];
-
- std::cout << "\n*** Found miscompiling pass '-" << ThePass->getPassArgument()
- << "': " << ThePass->getPassName() << "\n";
+ std::cout << "\n*** Found miscompiling pass"
+ << (getPassesToRun().size() == 1 ? "" : "es") << ": "
+ << getPassesString(getPassesToRun()) << '\n';
+ EmitProgressBytecode("passinput");
+
+ std::vector<Function*> MiscompiledFunctions =
+ DebugAMiscompilation(*this, TestOptimizer);
+
+ // 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.
- if (LastGood != 0) {
- std::vector<const PassInfo*> P(PassesToRun.begin(),
- PassesToRun.begin()+LastGood);
- std::string Filename;
- std::cout << "Running good passes to get input for pass:";
- if (runPasses(P, Filename, false, true)) {
- std::cerr << "ERROR: Running the first " << LastGood
- << " passes crashed!\n";
- return true;
+ std::cout << " Portion that is input to optimizer: ";
+ ToOptimize = swapProgramIn(ToOptimize);
+ EmitProgressBytecode("tooptimize");
+ setNewProgram(ToOptimize); // Delete hacked module.
+
+ return false;
+}
+
+/// 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);
}
- std::cout << " done!\n";
+
+ // 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.
- // Assuming everything was successful, we now have a valid bytecode file in
- // OutputName. Use it for "Program" Instead.
- delete Program;
- Program = ParseInputFile(Filename);
+ // 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);
- // Delete the file now.
- removeFile(Filename);
+ // 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(funcName, GEPargs);
+ std::vector<Value*> ResolverArgs;
+ ResolverArgs.push_back(GEP);
+
+ // Rewrite uses of F in global initializers, etc. to uses of a wrapper
+ // function that dynamically resolves the calls to F via our JIT API
+ if (F->use_begin() != F->use_end()) {
+ // Construct a new stub function that will re-route calls to F
+ const FunctionType *FuncTy = F->getFunctionType();
+ Function *FuncWrapper = new Function(FuncTy,
+ GlobalValue::InternalLinkage,
+ F->getName() + "_wrapper",
+ F->getParent());
+ BasicBlock *Header = new BasicBlock("header", FuncWrapper);
+
+ // Resolve the call to function F via the JIT API:
+ //
+ // call resolver(GetElementPtr...)
+ CallInst *resolve = new CallInst(resolverFunc, ResolverArgs,
+ "resolver");
+ Header->getInstList().push_back(resolve);
+ // cast the result from the resolver to correctly-typed function
+ CastInst *castResolver =
+ new CastInst(resolve, PointerType::get(F->getFunctionType()),
+ "resolverCast");
+ Header->getInstList().push_back(castResolver);
+
+ // Save the argument list
+ std::vector<Value*> Args;
+ for (Function::aiterator i = FuncWrapper->abegin(),
+ e = FuncWrapper->aend(); i != e; ++i)
+ Args.push_back(i);
+
+ // Pass on the arguments to the real function, return its result
+ if (F->getReturnType() == Type::VoidTy) {
+ CallInst *Call = new CallInst(castResolver, Args);
+ Header->getInstList().push_back(Call);
+ ReturnInst *Ret = new ReturnInst();
+ Header->getInstList().push_back(Ret);
+ } else {
+ CallInst *Call = new CallInst(castResolver, Args, "redir");
+ Header->getInstList().push_back(Call);
+ ReturnInst *Ret = new ReturnInst(Call);
+ Header->getInstList().push_back(Ret);
+ }
+
+ // Use the wrapper function instead of the old function
+ F->replaceAllUsesWith(FuncWrapper);
+ }
+ }
+ }
+ }
+
+ if (verifyModule(*Test) || verifyModule(*Safe)) {
+ std::cerr << "Bugpoint has a bug, which corrupted a module!!\n";
+ abort();
}
+}
+
- bool Result = debugPassMiscompilation(ThePass, Output);
- if (CreatedOutput) removeFile(Output);
+/// 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;
}
-/// debugPassMiscompilation - This method is called when the specified pass
-/// miscompiles Program as input. It tries to reduce the testcase to something
-/// that smaller that still miscompiles the program. ReferenceOutput contains
-/// the filename of the file containing the output we are to match.
+
+/// debugCodeGenerator - debug errors in LLC, LLI, or CBE.
///
-bool BugDriver::debugPassMiscompilation(const PassInfo *Pass,
- const std::string &ReferenceOutput) {
- EmitProgressBytecode(Pass, "passinput");
-
- // Loop over all of the functions in the program, attempting to find one that
- // is being miscompiled. We do this by extracting the function into a module,
- // running the "bad" optimization on that module, then linking it back into
- // the program. If the program fails the diff, the function got misoptimized.
- //
+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";
return false;
}
projects / oota-llvm.git / blobdiff