llvm-6502/tools/bugpoint/Miscompilation.cpp
Chris Lattner 9f71e799c3 Another formatting fix
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9216 91177308-0d34-0410-b5e6-96231b3b80d8
2003-10-18 00:05:05 +00:00

305 lines
11 KiB
C++

//===- Miscompilation.cpp - Debug program miscompilations -----------------===//
//
// This file implements program miscompilation debugging support.
//
//===----------------------------------------------------------------------===//
#include "BugDriver.h"
#include "ListReducer.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/Linker.h"
#include "Support/FileUtilities.h"
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::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(1);
}
// 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!
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: ";
// 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.
//
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(1);
}
// 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.
//
Module *PrefixOutput = BD.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
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"
<< " on the input program!\n";
BD.setPassesToRun(Suffix);
BD.EmitProgressBytecode("pass-error", false);
exit(1);
}
// 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!
BD.Program = OriginalInput; // Restore original program
delete PrefixOutput; // Free experiment
return NoFailure;
}
class ReduceMiscompilingFunctions : public ListReducer<Function*> {
BugDriver &BD;
public:
ReduceMiscompilingFunctions(BugDriver &bd) : BD(bd) {}
virtual TestResult doTest(std::vector<Function*> &Prefix,
std::vector<Function*> &Suffix) {
if (!Suffix.empty() && TestFuncs(Suffix, false))
return KeepSuffix;
if (!Prefix.empty() && TestFuncs(Prefix, false))
return KeepPrefix;
return NoFailure;
}
bool TestFuncs(const std::vector<Function*> &Prefix, bool EmitBytecode);
};
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 these "
<< "functions are run\nthrough the passes: ";
BD.PrintFunctionList(Funcs);
std::cout << "\n";
} else {
std::cout <<"Outputting reduced bytecode files which expose the problem:\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);
}
// 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);
}
if (EmitBytecode) {
std::cout << " Portion that is input to optimizer: ";
std::swap(BD.Program, ToOptimize);
BD.EmitProgressBytecode("tooptimize");
std::swap(BD.Program, ToOptimize);
}
// 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.setPassesToRun(Suffix);
BD.EmitProgressBytecode("pass-error", false);
exit(1);
}
if (!EmitBytecode)
std::cout << "done.\n";
delete BD.Program; // Delete the old "ToOptimize" module
BD.Program = BD.ParseInputFile(BytecodeResult);
if (EmitBytecode) {
std::cout << " 'tooptimize' after being optimized: ";
BD.EmitProgressBytecode("optimized", true);
}
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
// 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.
}
std::cout << " Checking to see if the merged program executes correctly: ";
// Eighth step: Execute the program. If it does not match the expected
// output, then 'Funcs' are being misoptimized!
bool Broken = BD.diffProgram();
delete BD.Program; // Delete the hacked up program
BD.Program = OldProgram; // Restore the original
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 (!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");
// 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);
// Do the reduction...
ReduceMiscompilingFunctions(*this).reduceList(MiscompiledFunctions);
std::cout << "\n*** The following functions are being miscompiled: ";
PrintFunctionList(MiscompiledFunctions);
std::cout << "\n";
// Output a bunch of bytecode files for the user...
ReduceMiscompilingFunctions(*this).TestFuncs(MiscompiledFunctions, true);
return false;
}