//===- Miscompilation.cpp - Debug program miscompilations -----------------===//
-//
+//
// The LLVM Compiler Infrastructure
//
-// 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 is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
-// This file implements program miscompilation debugging support.
+// This file implements optimizer and code generation miscompilation debugging
+// support.
//
//===----------------------------------------------------------------------===//
#include "BugDriver.h"
#include "ListReducer.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/Linker.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/FileUtilities.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FileUtilities.h"
+#include "llvm/Config/config.h" // for HAVE_LINK_R
using namespace llvm;
namespace llvm {
+ extern cl::list<std::string> InputArgv;
+}
+
+namespace {
+ static llvm::cl::opt<bool>
+ DisableLoopExtraction("disable-loop-extraction",
+ cl::desc("Don't extract loops when searching for miscompilations"),
+ cl::init(false));
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);
};
}
+/// TestResult - After passes have been split into a test group and a control
+/// group, see if they still break the program.
+///
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: ";
+ << "' compiles correctly: ";
- std::string BytecodeResult;
- if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
- std::cerr << " Error running this sequence of passes"
+ std::string BitcodeResult;
+ if (BD.runPasses(Suffix, BitcodeResult, 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);
+ BD.EmitProgressBitcode("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!
+ if (BD.diffProgram(BitcodeResult, "", true /*delete bitcode*/)) {
+ std::cout << " nope.\n";
+ if (Suffix.empty()) {
+ std::cerr << BD.getToolName() << ": I'm confused: the test fails when "
+ << "no passes are run, nondeterministic program?\n";
+ exit(1);
+ }
+ return KeepSuffix; // Miscompilation detected!
}
- std::cout << "yup.\n"; // No miscompilation!
+ std::cout << " yup.\n"; // No miscompilation!
if (Prefix.empty()) return NoFailure;
// 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: ";
+ << "' compiles 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
+ // kept passes, we can update our bitcode file to include the result of the
// prefix passes, then discard the prefix passes.
//
- if (BD.runPasses(Prefix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
- std::cerr << " Error running this sequence of passes"
+ if (BD.runPasses(Prefix, BitcodeResult, 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);
+ BD.EmitProgressBitcode("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);
+ if (BD.diffProgram(BitcodeResult)) {
+ std::cout << " nope.\n";
+ sys::Path(BitcodeResult).eraseFromDisk();
return KeepPrefix;
}
- std::cout << "yup.\n"; // No miscompilation!
+ 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.
//
- Module *PrefixOutput = BD.ParseInputFile(BytecodeResult);
+ Module *PrefixOutput = ParseInputFile(BitcodeResult, BD.getContext());
if (PrefixOutput == 0) {
- std::cerr << BD.getToolName() << ": Error reading bytecode file '"
- << BytecodeResult << "'!\n";
+ std::cerr << BD.getToolName() << ": Error reading bitcode file '"
+ << BitcodeResult << "'!\n";
exit(1);
}
- removeFile(BytecodeResult); // No longer need the file on disk
-
+ sys::Path(BitcodeResult).eraseFromDisk(); // 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.Program;
- BD.Program = PrefixOutput;
- if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
- std::cerr << " Error running this sequence of passes"
+ Module *OriginalInput = BD.swapProgramIn(PrefixOutput);
+ if (BD.runPasses(Suffix, BitcodeResult, 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);
+ BD.EmitProgressBitcode("pass-error", false);
exit(BD.debugOptimizerCrash());
}
// Run the result...
- if (BD.diffProgram(BytecodeResult, "", true/*delete bytecode*/)) {
- std::cout << "nope.\n";
+ if (BD.diffProgram(BitcodeResult, "", true/*delete bitcode*/)) {
+ 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
+ std::cout << " yup.\n"; // No miscompilation!
+ delete BD.swapProgramIn(OriginalInput); // Restore orig program & free test
return NoFailure;
}
-namespace llvm {
+namespace {
class ReduceMiscompilingFunctions : public ListReducer<Function*> {
BugDriver &BD;
+ bool (*TestFn)(BugDriver &, Module *, Module *);
public:
- ReduceMiscompilingFunctions(BugDriver &bd) : BD(bd) {}
-
+ 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, false))
+ if (!Suffix.empty() && TestFuncs(Suffix))
return KeepSuffix;
- if (!Prefix.empty() && TestFuncs(Prefix, false))
+ if (!Prefix.empty() && TestFuncs(Prefix))
return KeepPrefix;
return NoFailure;
}
-
- bool TestFuncs(const std::vector<Function*> &Prefix, bool EmitBytecode);
+
+ bool TestFuncs(const std::vector<Function*> &Prefix);
};
}
-bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs,
- bool EmitBytecode) {
- // 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 "
- << (Funcs.size()==1 ? "this function is" : "these functions are")
- << " run through the pass"
- << (BD.PassesToRun.size() == 1 ? "" : "es") << ": ";
- BD.PrintFunctionList(Funcs);
- std::cout << "\n";
- } else {
- std::cout <<"Outputting reduced bytecode files which expose the problem:\n";
+/// 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);
+ M2 = CloneModule(M2);
+ }
+ if (Linker::LinkModules(M1, M2, &ErrorMsg)) {
+ std::cerr << BD.getToolName() << ": Error linking modules together:"
+ << ErrorMsg << '\n';
+ exit(1);
}
+ delete M2; // We are done with this module.
- // First step: clone the module for the two halves of the program we want.
- Module *ToOptimize = CloneModule(BD.getProgram());
+ Module *OldProgram = BD.swapProgramIn(M1);
- // 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();
+ // 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.
+ DenseMap<const Value*, Value*> ValueMap;
+ Module *ToNotOptimize = CloneModule(BD.getProgram(), ValueMap);
+ Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, Funcs,
+ ValueMap);
+
+ // Run the predicate, note 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);
+ // Agree with the CBE on symbol naming
+ Mang.markCharUnacceptable('.');
+ Mang.setPreserveAsmNames(true);
+ for (Module::global_iterator I = M->global_begin(), E = M->global_end();
I != E; ++I)
- I->setInitializer(0); // Delete the initializer to make it external
+ I->setName(Mang.getMangledName(I));
+ for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
+ I->setName(Mang.getMangledName(I));
+}
- if (EmitBytecode) {
- std::cout << " Non-optimized portion: ";
- std::swap(BD.Program, ToNotOptimize);
- BD.EmitProgressBytecode("tonotoptimize", true);
- std::swap(BD.Program, ToNotOptimize);
- }
+/// 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) {
+ if (BugpointIsInterrupted) return MadeChange;
+
+ DenseMap<const Value*, Value*> ValueMap;
+ Module *ToNotOptimize = CloneModule(BD.getProgram(), ValueMap);
+ Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
+ MiscompiledFunctions,
+ ValueMap);
+ 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;
+ }
- // 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);
+ std::cerr << "Extracted a loop from the breaking portion of the program.\n";
+
+ // 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.switchToSafeInterpreter();
+ 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";
+
+ BD.writeProgramToFile("bugpoint-loop-extract-fail-tno.bc", ToNotOptimize);
+ BD.writeProgramToFile("bugpoint-loop-extract-fail-to.bc", ToOptimize);
+ BD.writeProgramToFile("bugpoint-loop-extract-fail-to-le.bc",
+ ToOptimizeLoopExtracted);
+
+ std::cerr << "Please submit the bugpoint-loop-extract-fail-*.bc files.\n";
+ delete ToOptimize;
+ delete ToNotOptimize;
+ delete ToOptimizeLoopExtracted;
+ return MadeChange;
+ }
+ delete ToOptimize;
+ 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";
+
+ std::vector<std::pair<std::string, const FunctionType*> > MisCompFunctions;
+ for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
+ E = ToOptimizeLoopExtracted->end(); I != E; ++I)
+ if (!I->isDeclaration())
+ MisCompFunctions.push_back(std::make_pair(I->getName(),
+ I->getFunctionType()));
+
+ // 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 (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted, &ErrorMsg)){
+ std::cerr << BD.getToolName() << ": Error linking modules together:"
+ << ErrorMsg << '\n';
+ exit(1);
+ }
+ delete ToOptimizeLoopExtracted;
+
+ // 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 (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
+ Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
+
+ assert(NewF && "Function not found??");
+ assert(NewF->getFunctionType() == MisCompFunctions[i].second &&
+ "found wrong function type?");
+ MiscompiledFunctions.push_back(NewF);
}
- if (EmitBytecode) {
- std::cout << " Portion that is input to optimizer: ";
- std::swap(BD.Program, ToOptimize);
- BD.EmitProgressBytecode("tooptimize");
- std::swap(BD.Program, ToOptimize);
+ BD.setNewProgram(ToNotOptimize);
+ MadeChange = true;
}
+}
- // Sixth step: Run the optimization passes on ToOptimize, producing a
- // transformed version of the functions being tested.
- Module *OldProgram = BD.Program;
- BD.Program = ToOptimize;
-
- if (!EmitBytecode)
- std::cout << " Optimizing functions being tested: ";
- std::string BytecodeResult;
- if (BD.runPasses(BD.PassesToRun, BytecodeResult, false/*delete*/,
- true/*quiet*/)) {
- std::cerr << " Error running this sequence of passes"
- << " on the input program!\n";
- BD.EmitProgressBytecode("pass-error", false);
- exit(BD.debugOptimizerCrash());
- }
+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);
+ };
+}
- if (!EmitBytecode)
- std::cout << "done.\n";
+/// 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.
+ DenseMap<const Value*, Value*> ValueMap;
+ Module *ToNotOptimize = CloneModule(BD.getProgram(), ValueMap);
+ Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
+ FunctionsBeingTested,
+ ValueMap);
+
+ // 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;
+}
- delete BD.getProgram(); // Delete the old "ToOptimize" module
- BD.Program = BD.ParseInputFile(BytecodeResult);
- if (EmitBytecode) {
- std::cout << " 'tooptimize' after being optimized: ";
- BD.EmitProgressBytecode("optimized", true);
+/// 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) {
+ if (BugpointIsInterrupted) return false;
+
+ 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;
}
- if (BD.Program == 0) {
- std::cerr << BD.getToolName() << ": Error reading bytecode file '"
- << BytecodeResult << "'!\n";
- exit(1);
+ DenseMap<const Value*, Value*> ValueMap;
+ Module *ProgClone = CloneModule(BD.getProgram(), ValueMap);
+ Module *ToExtract = SplitFunctionsOutOfModule(ProgClone,
+ MiscompiledFunctions,
+ ValueMap);
+ Module *Extracted = BD.ExtractMappedBlocksFromModule(Blocks, ToExtract);
+ if (Extracted == 0) {
+ // Weird, extraction should have worked.
+ std::cerr << "Nondeterministic problem extracting blocks??\n";
+ delete ProgClone;
+ delete ToExtract;
+ return false;
}
- removeFile(BytecodeResult); // No longer need the file on disk
- // Seventh step: Link the optimized part of the program back to the
- // unoptimized part of the program.
- //
- if (LinkModules(BD.Program, ToNotOptimize, &BytecodeResult)) {
+ // Otherwise, block extraction succeeded. Link the two program fragments back
+ // together.
+ delete ToExtract;
+
+ std::vector<std::pair<std::string, const FunctionType*> > MisCompFunctions;
+ for (Module::iterator I = Extracted->begin(), E = Extracted->end();
+ I != E; ++I)
+ if (!I->isDeclaration())
+ MisCompFunctions.push_back(std::make_pair(I->getName(),
+ I->getFunctionType()));
+
+ std::string ErrorMsg;
+ if (Linker::LinkModules(ProgClone, Extracted, &ErrorMsg)) {
std::cerr << BD.getToolName() << ": Error linking modules together:"
- << BytecodeResult << "\n";
+ << ErrorMsg << '\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.
- }
+ delete Extracted;
- std::cout << " Checking to see if the merged program executes correctly: ";
+ // Set the new program and delete the old one.
+ BD.setNewProgram(ProgClone);
- // Eighth step: Execute the program. If it does not match the expected
- // output, then 'Funcs' are being misoptimized!
- bool Broken = BD.diffProgram();
+ // Update the list of miscompiled functions.
+ MiscompiledFunctions.clear();
- delete BD.Program; // Delete the hacked up program
- BD.Program = OldProgram; // Restore the original
+ for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
+ Function *NewF = ProgClone->getFunction(MisCompFunctions[i].first);
+ assert(NewF && "Function not found??");
+ assert(NewF->getFunctionType() == MisCompFunctions[i].second &&
+ "Function has wrong type??");
+ MiscompiledFunctions.push_back(NewF);
+ }
- std::cout << (Broken ? " nope.\n" : " yup.\n");
- return Broken;
+ return true;
}
-/// debugMiscompilation - This method is used when the passes selected are not
-/// crashing, but the generated output is semantically different from the
-/// input.
+/// DebugAMiscompilation - This is a generic driver to narrow down
+/// miscompilations, either in an optimization or a code generator.
///
-bool BugDriver::debugMiscompilation() {
- // Make sure something was miscompiled...
- 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";
- EmitProgressBytecode("passinput");
-
+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;
- for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
- if (!I->isExternal())
+ Module *Prog = BD.getProgram();
+ for (Module::iterator I = Prog->begin(), E = Prog->end(); I != E; ++I)
+ if (!I->isDeclaration())
MiscompiledFunctions.push_back(I);
// Do the reduction...
- ReduceMiscompilingFunctions(*this).reduceList(MiscompiledFunctions);
+ if (!BugpointIsInterrupted)
+ ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions);
std::cout << "\n*** The following function"
<< (MiscompiledFunctions.size() == 1 ? " is" : "s are")
<< " being miscompiled: ";
PrintFunctionList(MiscompiledFunctions);
- std::cout << "\n";
+ std::cout << '\n';
+
+ // See if we can rip any loops out of the miscompiled functions and still
+ // trigger the problem.
+
+ if (!BugpointIsInterrupted && !DisableLoopExtraction &&
+ 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...
+ if (!BugpointIsInterrupted)
+ 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 (!BugpointIsInterrupted &&
+ 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;
+}
- // Output a bunch of bytecode files for the user...
- ReduceMiscompilingFunctions(*this).TestFuncs(MiscompiledFunctions, true);
+
+/// 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 (!BugpointIsInterrupted)
+ 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"
+ << (getPassesToRun().size() == 1 ? "" : "es") << ": "
+ << getPassesString(getPassesToRun()) << '\n';
+ EmitProgressBitcode("passinput");
+
+ std::vector<Function*> MiscompiledFunctions =
+ DebugAMiscompilation(*this, TestOptimizer);
+
+ // Output a bunch of bitcode files for the user...
+ std::cout << "Outputting reduced bitcode files which expose the problem:\n";
+ DenseMap<const Value*, Value*> ValueMap;
+ Module *ToNotOptimize = CloneModule(getProgram(), ValueMap);
+ Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
+ MiscompiledFunctions,
+ ValueMap);
+
+ std::cout << " Non-optimized portion: ";
+ ToNotOptimize = swapProgramIn(ToNotOptimize);
+ EmitProgressBitcode("tonotoptimize", true);
+ setNewProgram(ToNotOptimize); // Delete hacked module.
+
+ std::cout << " Portion that is input to optimizer: ";
+ ToOptimize = swapProgramIn(ToOptimize);
+ EmitProgressBitcode("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) {
+ LLVMContext &Context = BD.getContext();
+
+ // 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->getFunction("main"))
+ if (!oldMain->isDeclaration()) {
+ // Rename it
+ oldMain->setName("llvm_bugpoint_old_main");
+ // Create a NEW `main' function with same type in the test module.
+ Function *newMain = Function::Create(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 = Function::Create(oldMain->getFunctionType(),
+ GlobalValue::ExternalLinkage,
+ oldMain->getName(), Test);
+ // Set up and remember the argument list for the main function.
+ std::vector<Value*> args;
+ for (Function::arg_iterator
+ I = newMain->arg_begin(), E = newMain->arg_end(),
+ OI = oldMain->arg_begin(); 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 = BasicBlock::Create("entry", newMain);
+ CallInst *call = CallInst::Create(oldMainProto, args.begin(), args.end(),
+ "", BB);
+
+ // If the type of old function wasn't void, return value of call
+ ReturnInst::Create(call, BB);
+ }
+
+ // 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)
+ Constant *resolverFunc =
+ Safe->getOrInsertFunction("getPointerToNamedFunction",
+ Context.getPointerTypeUnqual(Type::Int8Ty),
+ Context.getPointerTypeUnqual(Type::Int8Ty), (Type *)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->isDeclaration() && !F->use_empty() && &*F != resolverFunc &&
+ !F->isIntrinsic() /* ignore intrinsics */) {
+ Function *TestFn = Test->getFunction(F->getName());
+
+ // Don't forward functions which are external in the test module too.
+ if (TestFn && !TestFn->isDeclaration()) {
+ // 1. Add a string constant with its name to the global file
+ Constant *InitArray = Context.getConstantArray(F->getName());
+ GlobalVariable *funcName =
+ new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/,
+ GlobalValue::InternalLinkage, InitArray,
+ F->getName() + "_name");
+
+ // 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, Context.getNullValue(Type::Int32Ty));
+ Value *GEP =
+ Context.getConstantExprGetElementPtr(funcName, &GEPargs[0], 2);
+ 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_empty()) {
+ // Create a new global to hold the cached function pointer.
+ Constant *NullPtr = Context.getConstantPointerNull(F->getType());
+ GlobalVariable *Cache =
+ new GlobalVariable(*F->getParent(), F->getType(),
+ false, GlobalValue::InternalLinkage,
+ NullPtr,F->getName()+".fpcache");
+
+ // Construct a new stub function that will re-route calls to F
+ const FunctionType *FuncTy = F->getFunctionType();
+ Function *FuncWrapper = Function::Create(FuncTy,
+ GlobalValue::InternalLinkage,
+ F->getName() + "_wrapper",
+ F->getParent());
+ BasicBlock *EntryBB = BasicBlock::Create("entry", FuncWrapper);
+ BasicBlock *DoCallBB = BasicBlock::Create("usecache", FuncWrapper);
+ BasicBlock *LookupBB = BasicBlock::Create("lookupfp", FuncWrapper);
+
+ // Check to see if we already looked up the value.
+ Value *CachedVal = new LoadInst(Cache, "fpcache", EntryBB);
+ Value *IsNull = new ICmpInst(*EntryBB, ICmpInst::ICMP_EQ, CachedVal,
+ NullPtr, "isNull");
+ BranchInst::Create(LookupBB, DoCallBB, IsNull, EntryBB);
+
+ // Resolve the call to function F via the JIT API:
+ //
+ // call resolver(GetElementPtr...)
+ CallInst *Resolver =
+ CallInst::Create(resolverFunc, ResolverArgs.begin(),
+ ResolverArgs.end(), "resolver", LookupBB);
+
+ // Cast the result from the resolver to correctly-typed function.
+ CastInst *CastedResolver =
+ new BitCastInst(Resolver,
+ Context.getPointerTypeUnqual(F->getFunctionType()),
+ "resolverCast", LookupBB);
+
+ // Save the value in our cache.
+ new StoreInst(CastedResolver, Cache, LookupBB);
+ BranchInst::Create(DoCallBB, LookupBB);
+
+ PHINode *FuncPtr = PHINode::Create(NullPtr->getType(),
+ "fp", DoCallBB);
+ FuncPtr->addIncoming(CastedResolver, LookupBB);
+ FuncPtr->addIncoming(CachedVal, EntryBB);
+
+ // Save the argument list.
+ std::vector<Value*> Args;
+ for (Function::arg_iterator i = FuncWrapper->arg_begin(),
+ e = FuncWrapper->arg_end(); i != e; ++i)
+ Args.push_back(i);
+
+ // Pass on the arguments to the real function, return its result
+ if (F->getReturnType() == Type::VoidTy) {
+ CallInst::Create(FuncPtr, Args.begin(), Args.end(), "", DoCallBB);
+ ReturnInst::Create(DoCallBB);
+ } else {
+ CallInst *Call = CallInst::Create(FuncPtr, Args.begin(), Args.end(),
+ "retval", DoCallBB);
+ ReturnInst::Create(Call, DoCallBB);
+ }
+
+ // 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();
+ }
+}
+
+
+
+/// 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);
+
+ sys::Path TestModuleBC("bugpoint.test.bc");
+ std::string ErrMsg;
+ if (TestModuleBC.makeUnique(true, &ErrMsg)) {
+ std::cerr << BD.getToolName() << "Error making unique filename: "
+ << ErrMsg << "\n";
+ exit(1);
+ }
+ if (BD.writeProgramToFile(TestModuleBC.toString(), Test)) {
+ std::cerr << "Error writing bitcode to `" << TestModuleBC << "'\nExiting.";
+ exit(1);
+ }
+ delete Test;
+
+ // Make the shared library
+ sys::Path SafeModuleBC("bugpoint.safe.bc");
+ if (SafeModuleBC.makeUnique(true, &ErrMsg)) {
+ std::cerr << BD.getToolName() << "Error making unique filename: "
+ << ErrMsg << "\n";
+ exit(1);
+ }
+
+ if (BD.writeProgramToFile(SafeModuleBC.toString(), Safe)) {
+ std::cerr << "Error writing bitcode to `" << SafeModuleBC << "'\nExiting.";
+ exit(1);
+ }
+ std::string SharedObject = BD.compileSharedObject(SafeModuleBC.toString());
+ 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.toString(), SharedObject, false);
+
+ if (Result)
+ std::cerr << ": still failing!\n";
+ else
+ std::cerr << ": didn't fail.\n";
+ TestModuleBC.eraseFromDisk();
+ SafeModuleBC.eraseFromDisk();
+ sys::Path(SharedObject).eraseFromDisk();
+
+ return Result;
+}
+
+
+/// debugCodeGenerator - debug errors in LLC, LLI, or CBE.
+///
+bool BugDriver::debugCodeGenerator() {
+ if ((void*)SafeInterpreter == (void*)Interpreter) {
+ std::string Result = executeProgramSafely("bugpoint.safe.out");
+ std::cout << "\n*** The \"safe\" i.e. 'known good' backend cannot match "
+ << "the reference diff. This may be due to a\n front-end "
+ << "bug or a bug in the original program, but this can also "
+ << "happen if bugpoint isn't running the program with the "
+ << "right flags or input.\n I left the result of executing "
+ << "the program with the \"safe\" backend 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.
+ DenseMap<const Value*, Value*> ValueMap;
+ Module *ToNotCodeGen = CloneModule(getProgram(), ValueMap);
+ Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs, ValueMap);
+
+ // Condition the modules
+ CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen);
+
+ sys::Path TestModuleBC("bugpoint.test.bc");
+ std::string ErrMsg;
+ if (TestModuleBC.makeUnique(true, &ErrMsg)) {
+ std::cerr << getToolName() << "Error making unique filename: "
+ << ErrMsg << "\n";
+ exit(1);
+ }
+
+ if (writeProgramToFile(TestModuleBC.toString(), ToCodeGen)) {
+ std::cerr << "Error writing bitcode to `" << TestModuleBC << "'\nExiting.";
+ exit(1);
+ }
+ delete ToCodeGen;
+
+ // Make the shared library
+ sys::Path SafeModuleBC("bugpoint.safe.bc");
+ if (SafeModuleBC.makeUnique(true, &ErrMsg)) {
+ std::cerr << getToolName() << "Error making unique filename: "
+ << ErrMsg << "\n";
+ exit(1);
+ }
+
+ if (writeProgramToFile(SafeModuleBC.toString(), ToNotCodeGen)) {
+ std::cerr << "Error writing bitcode to `" << SafeModuleBC << "'\nExiting.";
+ exit(1);
+ }
+ std::string SharedObject = compileSharedObject(SafeModuleBC.toString());
+ 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 -f " << TestModuleBC << " -o " << TestModuleBC<< ".s\n";
+ std::cout << " gcc " << SharedObject << " " << TestModuleBC
+ << ".s -o " << TestModuleBC << ".exe";
+#if defined (HAVE_LINK_R)
+ std::cout << " -Wl,-R.";
+#endif
+ std::cout << "\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
+ << " -fPIC -shared" // `-shared' for Linux/X86, maybe others
+#endif
+ << " -fno-strict-aliasing\n";
+
+ return false;
+}
projects / oota-llvm.git / blobdiff