Implement support for bugpoint to identify which FUNCTION an optimization

is miscompiling.

llvm-svn: 5893
This commit is contained in:
Chris Lattner 2003-04-24 17:02:17 +00:00
parent 0aebf8f80a
commit 16a413103c
6 changed files with 412 additions and 88 deletions

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@ -14,6 +14,20 @@
#include "llvm/Pass.h"
#include <memory>
/// getPassesString - Turn a list of passes into a string which indicates the
/// command line options that must be passed to add the passes.
///
std::string getPassesString(const std::vector<const PassInfo*> &Passes) {
std::string Result;
for (unsigned i = 0, e = Passes.size(); i != e; ++i) {
if (i) Result += " ";
Result += "-";
Result += Passes[i]->getPassArgument();
}
return Result;
}
/// ParseInputFile - Given a bytecode or assembly input filename, parse and
/// return it, or return null if not possible.
///

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@ -17,11 +17,17 @@ class Function;
class AbstractInterpreter;
class Instruction;
class ReduceMiscompilingPasses;
class ReduceMiscompilingFunctions;
class BugDriver {
const std::string ToolName; // Name of bugpoint
Module *Program; // The raw program, linked together
std::vector<const PassInfo*> PassesToRun;
AbstractInterpreter *Interpreter; // How to run the program
friend class ReduceMiscompilingPasses;
friend class ReduceMiscompilingFunctions;
public:
BugDriver(const char *toolname)
: ToolName(toolname), Program(0), Interpreter(0) {}
@ -81,7 +87,7 @@ private:
/// EmitProgressBytecode - This function is used to output the current Program
/// to a file named "bugpoing-ID.bc".
///
void EmitProgressBytecode(const PassInfo *Pass, const std::string &ID);
void EmitProgressBytecode(const std::string &ID, bool NoFlyer = false);
/// runPasses - Run the specified passes on Program, outputting a bytecode
/// file and writting the filename into OutputFile if successful. If the
@ -148,7 +154,13 @@ private:
/// is different, true is returned.
///
bool diffProgram(const std::string &ReferenceOutputFile,
const std::string &BytecodeFile = "");
const std::string &BytecodeFile = "",
bool RemoveBytecode = false);
};
/// getPassesString - Turn a list of passes into a string which indicates the
/// command line options that must be passed to add the passes.
///
std::string getPassesString(const std::vector<const PassInfo*> &Passes);
#endif

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@ -11,6 +11,23 @@
#include "llvm/Pass.h"
#include <fstream>
#if 0
class DebugCrashes : public ListReducer<const PassInfo*> {
BugDriver &BD;
public:
DebugCrashes(BugDriver &bd) : BD(bd) {}
// doTest - Return true iff running the "removed" passes succeeds, and running
// the "Kept" passes fail when run on the output of the "removed" passes. If
// we return true, we update the current module of bugpoint.
//
virtual bool doTest(const std::vector<ElTy> &Removed,
const std::vector<ElTy> &Kept) {
return BD.runPasses(Kept);
}
};
#endif
/// debugCrash - This method is called when some pass crashes on input. It
/// attempts to prune down the testcase to something reasonable, and figure
/// out exactly which pass is crashing.
@ -18,7 +35,11 @@
bool BugDriver::debugCrash() {
std::cout << "\n*** Debugging optimizer crash!\n";
// Determine which pass causes the optimizer to crash... using binary search
#if 0
// Reduce the list of passes which causes the optimizer to crash...
DebugCrashes(*this).reduceList(PassesToRun);
#endif
unsigned LastToPass = 0, LastToCrash = PassesToRun.size();
while (LastToPass != LastToCrash) {
unsigned Mid = (LastToCrash+LastToPass+1) / 2;
@ -65,6 +86,9 @@ bool BugDriver::debugCrash() {
removeFile(Filename);
}
PassesToRun.clear();
PassesToRun.push_back(CrashingPass);
return debugPassCrash(CrashingPass);
}
@ -83,7 +107,7 @@ static unsigned CountFunctions(Module *M) {
/// crashes, but it smaller.
///
bool BugDriver::debugPassCrash(const PassInfo *Pass) {
EmitProgressBytecode(Pass, "passinput");
EmitProgressBytecode("passinput");
bool Reduced = false, AnyReduction = false;
if (CountFunctions(Program) > 1) {
@ -124,7 +148,7 @@ bool BugDriver::debugPassCrash(const PassInfo *Pass) {
}
if (Reduced) {
EmitProgressBytecode(Pass, "reduced-function");
EmitProgressBytecode("reduced-function");
Reduced = false;
}
@ -196,7 +220,7 @@ bool BugDriver::debugPassCrash(const PassInfo *Pass) {
}
if (Reduced) {
EmitProgressBytecode(Pass, "reduced-simplified");
EmitProgressBytecode("reduced-simplified");
Reduced = false;
}

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@ -164,7 +164,8 @@ std::string BugDriver::executeProgram(std::string OutputFile,
/// different, true is returned.
///
bool BugDriver::diffProgram(const std::string &ReferenceOutputFile,
const std::string &BytecodeFile) {
const std::string &BytecodeFile,
bool RemoveBytecode) {
// Execute the program, generating an output file...
std::string Output = executeProgram("", BytecodeFile);
@ -192,5 +193,6 @@ bool BugDriver::diffProgram(const std::string &ReferenceOutputFile,
} while (C1 != EOF);
removeFile(Output);
if (RemoveBytecode) removeFile(BytecodeFile);
return FilesDifferent;
}

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@ -8,6 +8,8 @@
#include "SystemUtils.h"
#include "llvm/Pass.h"
#include "llvm/Module.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/Linker.h"
#include "Support/CommandLine.h"
// Anonymous namespace to define command line options for miscompilation
@ -24,6 +26,322 @@ namespace {
"(for miscompilation detection)"));
}
template<typename ElTy>
struct ListReducer {
enum TestResult {
NoFailure, // No failure of the predicate was detected
KeepSuffix, // The suffix alone satisfies the predicate
KeepPrefix, // The prefix alone satisfies the predicate
};
// doTest - This virtual function should be overriden by subclasses to
// implement the test desired. The testcase is only required to test to see
// if the Kept list still satisfies the property, but if it is going to check
// the prefix anyway, it can.
//
virtual TestResult doTest(const std::vector<ElTy> &Prefix,
const std::vector<ElTy> &Kept) = 0;
// reduceList - This function attempts to reduce the length of the specified
// list while still maintaining the "test" property. This is the core of the
// "work" that bugpoint does.
//
void reduceList(std::vector<ElTy> &TheList) {
unsigned MidTop = TheList.size();
while (MidTop > 1) {
unsigned Mid = MidTop / 2;
std::vector<ElTy> Prefix(TheList.begin()+Mid, TheList.end());
std::vector<ElTy> Kept (TheList.begin(), TheList.begin()+Mid);
switch (doTest(Prefix, Kept)) {
case KeepSuffix:
// The property still holds. We can just drop the prefix elements, and
// shorten the list to the "kept" elements.
TheList.swap(Kept);
MidTop = TheList.size();
break;
case KeepPrefix:
// The predicate still holds, shorten the list to the prefix elements.
TheList.swap(Prefix);
MidTop = TheList.size();
break;
case NoFailure:
// Otherwise the property doesn't hold. Some of the elements we removed
// must be neccesary to maintain the property.
MidTop = Mid;
break;
}
}
}
};
class ReduceMiscompilingPasses : public ListReducer<const PassInfo*> {
BugDriver &BD;
public:
ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
virtual TestResult doTest(const std::vector<const PassInfo*> &Prefix,
const std::vector<const PassInfo*> &Kept);
};
ReduceMiscompilingPasses::TestResult
ReduceMiscompilingPasses::doTest(const std::vector<const PassInfo*> &Prefix,
const std::vector<const PassInfo*> &Kept) {
// First, run the program with just the Kept passes. If it is still broken
// with JUST the kept passes, discard the prefix passes.
std::cout << "Checking to see if '" << getPassesString(Kept)
<< "' compile correctly: ";
std::string BytecodeResult;
if (BD.runPasses(Kept, BytecodeResult, false/*delete*/, true/*quiet*/)) {
std::cerr << BD.getToolName() << ": Error running this sequence of passes"
<< " on the input program!\n";
exit(1);
}
// Check to see if the finished program matches the reference output...
if (BD.diffProgram(Output, BytecodeResult, true /*delete bytecode*/)) {
std::cout << "nope.\n";
return KeepSuffix; // Miscompilation detected!
}
std::cout << "yup.\n"; // No miscompilation!
if (Prefix.empty()) return NoFailure;
// First, run the program with just the Kept passes. If it is still broken
// with JUST the kept passes, discard the prefix 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 << BD.getToolName() << ": Error running this sequence of passes"
<< " on the input program!\n";
exit(1);
}
// If the prefix maintains the predicate by itself, only keep the prefix!
if (BD.diffProgram(Output, 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(Kept)
<< "' passes compile correctly after the '"
<< getPassesString(Prefix) << "' passes: ";
Module *OriginalInput = BD.Program;
BD.Program = PrefixOutput;
if (BD.runPasses(Kept, BytecodeResult, false/*delete*/, true/*quiet*/)) {
std::cerr << BD.getToolName() << ": Error running this sequence of passes"
<< " on the input program!\n";
exit(1);
}
// Run the result...
if (BD.diffProgram(Output, BytecodeResult, true/*delete bytecode*/)) {
std::cout << "nope.\n";
delete OriginalInput; // We pruned down the original input...
return KeepPrefix;
}
// 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;
}
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();
}
}
class ReduceMiscompilingFunctions : public ListReducer<Function*> {
BugDriver &BD;
public:
ReduceMiscompilingFunctions(BugDriver &bd) : BD(bd) {}
virtual TestResult doTest(const std::vector<Function*> &Prefix,
const std::vector<Function*> &Kept) {
if (TestFuncs(Kept, false))
return KeepSuffix;
if (TestFuncs(Prefix, false))
return KeepPrefix;
return NoFailure;
}
bool TestFuncs(const std::vector<Function*> &Prefix, bool EmitBytecode);
};
// DeleteFunctionBody - "Remove" the function by deleting all of it's basic
// blocks, making it external.
//
static void DeleteFunctionBody(Function *F) {
// First, break circular use/def chain references...
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I)
I->dropAllReferences();
// Next, delete all of the basic blocks.
F->getBasicBlockList().clear();
assert(F->isExternal() && "This didn't make the function external!");
}
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: ";
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 << BD.getToolName() << ": Error running this sequence of passes"
<< " on the input program!\n";
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(Output);
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.
@ -50,92 +368,42 @@ bool BugDriver::debugMiscompilation() {
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.
//
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";
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!
}
// We are now done with the optimized output... so remove it.
removeFile(BytecodeResult);
}
// Figure out which transformations miscompile the input program.
unsigned OldSize = PassesToRun.size();
ReduceMiscompilingPasses(*this).reduceList(PassesToRun);
// Make sure something was miscompiled...
if (LastBad >= PassesToRun.size()) {
if (PassesToRun.size() == OldSize) {
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";
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 << " done!\n";
// Assuming everything was successful, we now have a valid bytecode file in
// OutputName. Use it for "Program" Instead.
delete Program;
Program = ParseInputFile(Filename);
// Delete the file now.
removeFile(Filename);
}
std::cout << "\n*** Found miscompiling pass"
<< (PassesToRun.size() == 1 ? "" : "es") << ": "
<< getPassesString(PassesToRun) << "\n";
EmitProgressBytecode("passinput");
bool Result = debugPassMiscompilation(ThePass, Output);
// 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);
if (CreatedOutput) removeFile(Output);
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.
///
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.
//
return false;
}

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@ -35,8 +35,7 @@ bool BugDriver::writeProgramToFile(const std::string &Filename,
/// EmitProgressBytecode - This function is used to output the current Program
/// to a file named "bugpoing-ID.bc".
///
void BugDriver::EmitProgressBytecode(const PassInfo *Pass,
const std::string &ID) {
void BugDriver::EmitProgressBytecode(const std::string &ID, bool NoFlyer) {
// Output the input to the current pass to a bytecode file, emit a message
// telling the user how to reproduce it: opt -foo blah.bc
//
@ -47,9 +46,13 @@ void BugDriver::EmitProgressBytecode(const PassInfo *Pass,
}
std::cout << "Emitted bytecode to '" << Filename << "'\n";
if (NoFlyer) return;
std::cout << "\n*** You can reproduce the problem with: ";
unsigned PassType = Pass->getPassType();
unsigned PassType = PassesToRun[0]->getPassType();
for (unsigned i = 1, e = PassesToRun.size(); i != e; ++i)
PassType &= PassesToRun[i]->getPassType();
if (PassType & PassInfo::Analysis)
std::cout << "analyze";
else if (PassType & PassInfo::Optimization)
@ -58,7 +61,8 @@ void BugDriver::EmitProgressBytecode(const PassInfo *Pass,
std::cout << "llc";
else
std::cout << "bugpoint";
std::cout << " " << Filename << " -" << Pass->getPassArgument() << "\n";
std::cout << " " << Filename << " ";
std::cout << getPassesString(PassesToRun) << "\n";
}
/// FIXME: This should be parameterizable!!