mirror of
https://github.com/c64scene-ar/llvm-6502.git
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a148ccb158
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5905 91177308-0d34-0410-b5e6-96231b3b80d8
434 lines
16 KiB
C++
434 lines
16 KiB
C++
//===- Miscompilation.cpp - Debug program miscompilations -----------------===//
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//
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// This file implements program miscompilation debugging support.
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//
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//===----------------------------------------------------------------------===//
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#include "BugDriver.h"
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#include "SystemUtils.h"
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#include "llvm/Pass.h"
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#include "llvm/Module.h"
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#include "llvm/Transforms/Utils/Cloning.h"
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#include "llvm/Transforms/Utils/Linker.h"
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#include "Support/CommandLine.h"
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// Anonymous namespace to define command line options for miscompilation
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// debugging.
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//
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namespace {
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// Output - The user can specify a file containing the expected output of the
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// program. If this filename is set, it is used as the reference diff source,
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// otherwise the raw input run through an interpreter is used as the reference
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// source.
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//
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cl::opt<std::string>
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Output("output", cl::desc("Specify a reference program output "
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"(for miscompilation detection)"));
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}
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template<typename ElTy>
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struct ListReducer {
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enum TestResult {
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NoFailure, // No failure of the predicate was detected
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KeepSuffix, // The suffix alone satisfies the predicate
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KeepPrefix, // The prefix alone satisfies the predicate
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};
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// doTest - This virtual function should be overriden by subclasses to
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// implement the test desired. The testcase is only required to test to see
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// if the Kept list still satisfies the property, but if it is going to check
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// the prefix anyway, it can.
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//
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virtual TestResult doTest(const std::vector<ElTy> &Prefix,
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const std::vector<ElTy> &Kept) = 0;
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// reduceList - This function attempts to reduce the length of the specified
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// list while still maintaining the "test" property. This is the core of the
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// "work" that bugpoint does.
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//
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void reduceList(std::vector<ElTy> &TheList) {
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unsigned MidTop = TheList.size();
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while (MidTop > 1) {
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unsigned Mid = MidTop / 2;
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std::vector<ElTy> Prefix(TheList.begin()+Mid, TheList.end());
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std::vector<ElTy> Kept (TheList.begin(), TheList.begin()+Mid);
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switch (doTest(Prefix, Kept)) {
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case KeepSuffix:
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// The property still holds. We can just drop the prefix elements, and
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// shorten the list to the "kept" elements.
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TheList.swap(Kept);
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MidTop = TheList.size();
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break;
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case KeepPrefix:
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// The predicate still holds, shorten the list to the prefix elements.
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TheList.swap(Prefix);
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MidTop = TheList.size();
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break;
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case NoFailure:
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// Otherwise the property doesn't hold. Some of the elements we removed
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// must be neccesary to maintain the property.
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MidTop = Mid;
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break;
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}
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}
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// Okay, we trimmed as much off the top and the bottom of the list as we
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// could. If there is more two elements in the list, try deleting interior
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// elements and testing that.
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//
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if (TheList.size() > 2) {
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bool Changed = true;
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std::vector<ElTy> EmptyList;
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while (Changed) {
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Changed = false;
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std::vector<ElTy> TrimmedList;
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for (unsigned i = 1; i < TheList.size()-1; ++i) { // Check interior elts
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std::vector<ElTy> TestList(TheList);
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TestList.erase(TestList.begin()+i);
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if (doTest(EmptyList, TestList) == KeepSuffix) {
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// We can trim down the list!
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TheList.swap(TestList);
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--i; // Don't skip an element of the list
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Changed = true;
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}
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}
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}
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}
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}
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};
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class ReduceMiscompilingPasses : public ListReducer<const PassInfo*> {
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BugDriver &BD;
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public:
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ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
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virtual TestResult doTest(const std::vector<const PassInfo*> &Prefix,
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const std::vector<const PassInfo*> &Kept);
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};
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ReduceMiscompilingPasses::TestResult
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ReduceMiscompilingPasses::doTest(const std::vector<const PassInfo*> &Prefix,
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const std::vector<const PassInfo*> &Kept) {
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// First, run the program with just the Kept passes. If it is still broken
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// with JUST the kept passes, discard the prefix passes.
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std::cout << "Checking to see if '" << getPassesString(Kept)
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<< "' compile correctly: ";
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std::string BytecodeResult;
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if (BD.runPasses(Kept, BytecodeResult, false/*delete*/, true/*quiet*/)) {
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std::cerr << BD.getToolName() << ": Error running this sequence of passes"
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<< " on the input program!\n";
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exit(1);
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}
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// Check to see if the finished program matches the reference output...
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if (BD.diffProgram(Output, BytecodeResult, true /*delete bytecode*/)) {
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std::cout << "nope.\n";
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return KeepSuffix; // Miscompilation detected!
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}
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std::cout << "yup.\n"; // No miscompilation!
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if (Prefix.empty()) return NoFailure;
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// First, run the program with just the Kept passes. If it is still broken
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// with JUST the kept passes, discard the prefix passes.
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std::cout << "Checking to see if '" << getPassesString(Prefix)
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<< "' compile correctly: ";
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// If it is not broken with the kept passes, it's possible that the prefix
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// passes must be run before the kept passes to break it. If the program
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// WORKS after the prefix passes, but then fails if running the prefix AND
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// kept passes, we can update our bytecode file to include the result of the
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// prefix passes, then discard the prefix passes.
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//
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if (BD.runPasses(Prefix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
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std::cerr << BD.getToolName() << ": Error running this sequence of passes"
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<< " on the input program!\n";
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exit(1);
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}
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// If the prefix maintains the predicate by itself, only keep the prefix!
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if (BD.diffProgram(Output, BytecodeResult)) {
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std::cout << "nope.\n";
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removeFile(BytecodeResult);
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return KeepPrefix;
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}
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std::cout << "yup.\n"; // No miscompilation!
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// Ok, so now we know that the prefix passes work, try running the suffix
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// passes on the result of the prefix passes.
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//
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Module *PrefixOutput = BD.ParseInputFile(BytecodeResult);
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if (PrefixOutput == 0) {
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std::cerr << BD.getToolName() << ": Error reading bytecode file '"
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<< BytecodeResult << "'!\n";
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exit(1);
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}
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removeFile(BytecodeResult); // No longer need the file on disk
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std::cout << "Checking to see if '" << getPassesString(Kept)
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<< "' passes compile correctly after the '"
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<< getPassesString(Prefix) << "' passes: ";
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Module *OriginalInput = BD.Program;
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BD.Program = PrefixOutput;
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if (BD.runPasses(Kept, BytecodeResult, false/*delete*/, true/*quiet*/)) {
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std::cerr << BD.getToolName() << ": Error running this sequence of passes"
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<< " on the input program!\n";
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exit(1);
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}
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// Run the result...
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if (BD.diffProgram(Output, BytecodeResult, true/*delete bytecode*/)) {
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std::cout << "nope.\n";
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delete OriginalInput; // We pruned down the original input...
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return KeepPrefix;
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}
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// Otherwise, we must not be running the bad pass anymore.
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std::cout << "yup.\n"; // No miscompilation!
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BD.Program = OriginalInput; // Restore original program
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delete PrefixOutput; // Free experiment
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return NoFailure;
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}
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static void PrintFunctionList(const std::vector<Function*> &Funcs) {
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for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
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if (i) std::cout << ", ";
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std::cout << Funcs[i]->getName();
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}
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}
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class ReduceMiscompilingFunctions : public ListReducer<Function*> {
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BugDriver &BD;
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public:
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ReduceMiscompilingFunctions(BugDriver &bd) : BD(bd) {}
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virtual TestResult doTest(const std::vector<Function*> &Prefix,
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const std::vector<Function*> &Kept) {
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if (TestFuncs(Kept, false))
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return KeepSuffix;
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if (!Prefix.empty() && TestFuncs(Prefix, false))
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return KeepPrefix;
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return NoFailure;
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}
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bool TestFuncs(const std::vector<Function*> &Prefix, bool EmitBytecode);
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};
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// DeleteFunctionBody - "Remove" the function by deleting all of it's basic
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// blocks, making it external.
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//
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static void DeleteFunctionBody(Function *F) {
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// First, break circular use/def chain references...
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for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I)
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I->dropAllReferences();
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// Next, delete all of the basic blocks.
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F->getBasicBlockList().clear();
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assert(F->isExternal() && "This didn't make the function external!");
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}
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bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs,
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bool EmitBytecode) {
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// Test to see if the function is misoptimized if we ONLY run it on the
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// functions listed in Funcs.
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if (!EmitBytecode) {
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std::cout << "Checking to see if the program is misoptimized when these "
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<< "functions are run\nthrough the passes: ";
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PrintFunctionList(Funcs);
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std::cout << "\n";
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} else {
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std::cout <<"Outputting reduced bytecode files which expose the problem:\n";
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}
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// First step: clone the module for the two halves of the program we want.
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Module *ToOptimize = CloneModule(BD.Program);
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// Second step: Make sure functions & globals are all external so that linkage
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// between the two modules will work.
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for (Module::iterator I = ToOptimize->begin(), E = ToOptimize->end();I!=E;++I)
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I->setLinkage(GlobalValue::ExternalLinkage);
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for (Module::giterator I = ToOptimize->gbegin(), E = ToOptimize->gend();
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I != E; ++I)
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I->setLinkage(GlobalValue::ExternalLinkage);
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// Third step: make a clone of the externalized program for the non-optimized
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// part.
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Module *ToNotOptimize = CloneModule(ToOptimize);
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// Fourth step: Remove the test functions from the ToNotOptimize module, and
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// all of the global variables.
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for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
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Function *TNOF = ToNotOptimize->getFunction(Funcs[i]->getName(),
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Funcs[i]->getFunctionType());
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assert(TNOF && "Function doesn't exist in module!");
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DeleteFunctionBody(TNOF); // Function is now external in this module!
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}
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for (Module::giterator I = ToNotOptimize->gbegin(), E = ToNotOptimize->gend();
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I != E; ++I)
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I->setInitializer(0); // Delete the initializer to make it external
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if (EmitBytecode) {
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std::cout << " Non-optimized portion: ";
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std::swap(BD.Program, ToNotOptimize);
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BD.EmitProgressBytecode("tonotoptimize", true);
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std::swap(BD.Program, ToNotOptimize);
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}
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// Fifth step: Remove all functions from the ToOptimize module EXCEPT for the
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// ones specified in Funcs. We know which ones these are because they are
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// non-external in ToOptimize, but external in ToNotOptimize.
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//
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for (Module::iterator I = ToOptimize->begin(), E = ToOptimize->end();I!=E;++I)
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if (!I->isExternal()) {
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Function *TNOF = ToNotOptimize->getFunction(I->getName(),
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I->getFunctionType());
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assert(TNOF && "Function doesn't exist in ToNotOptimize module??");
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if (!TNOF->isExternal())
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DeleteFunctionBody(I);
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}
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if (EmitBytecode) {
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std::cout << " Portion that is input to optimizer: ";
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std::swap(BD.Program, ToOptimize);
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BD.EmitProgressBytecode("tooptimize");
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std::swap(BD.Program, ToOptimize);
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}
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// Sixth step: Run the optimization passes on ToOptimize, producing a
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// transformed version of the functions being tested.
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Module *OldProgram = BD.Program;
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BD.Program = ToOptimize;
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if (!EmitBytecode)
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std::cout << " Optimizing functions being tested: ";
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std::string BytecodeResult;
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if (BD.runPasses(BD.PassesToRun, BytecodeResult, false/*delete*/,
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true/*quiet*/)) {
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std::cerr << BD.getToolName() << ": Error running this sequence of passes"
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<< " on the input program!\n";
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exit(1);
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}
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if (!EmitBytecode)
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std::cout << "done.\n";
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delete BD.Program; // Delete the old "ToOptimize" module
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BD.Program = BD.ParseInputFile(BytecodeResult);
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if (EmitBytecode) {
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std::cout << " 'tooptimize' after being optimized: ";
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BD.EmitProgressBytecode("optimized", true);
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}
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if (BD.Program == 0) {
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std::cerr << BD.getToolName() << ": Error reading bytecode file '"
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<< BytecodeResult << "'!\n";
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exit(1);
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}
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removeFile(BytecodeResult); // No longer need the file on disk
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// Seventh step: Link the optimized part of the program back to the
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// unoptimized part of the program.
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//
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if (LinkModules(BD.Program, ToNotOptimize, &BytecodeResult)) {
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std::cerr << BD.getToolName() << ": Error linking modules together:"
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<< BytecodeResult << "\n";
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exit(1);
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}
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delete ToNotOptimize; // We are done with this module...
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if (EmitBytecode) {
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std::cout << " Program as tested: ";
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BD.EmitProgressBytecode("linked", true);
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delete BD.Program;
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BD.Program = OldProgram;
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return false; // We don't need to actually execute the program here.
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}
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std::cout << " Checking to see if the merged program executes correctly: ";
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// Eighth step: Execute the program. If it does not match the expected
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// output, then 'Funcs' are being misoptimized!
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bool Broken = BD.diffProgram(Output);
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delete BD.Program; // Delete the hacked up program
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BD.Program = OldProgram; // Restore the original
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std::cout << (Broken ? "nope.\n" : "yup.\n");
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return Broken;
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}
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/// debugMiscompilation - This method is used when the passes selected are not
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/// crashing, but the generated output is semantically different from the
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/// input.
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///
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bool BugDriver::debugMiscompilation() {
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std::cout << "*** Debugging miscompilation!\n";
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// Set up the execution environment, selecting a method to run LLVM bytecode.
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if (initializeExecutionEnvironment()) return true;
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// Run the raw input to see where we are coming from. If a reference output
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// was specified, make sure that the raw output matches it. If not, it's a
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// problem in the front-end or whatever produced the input code.
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//
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bool CreatedOutput = false;
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if (Output.empty()) {
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std::cout << "Generating reference output from raw program...";
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Output = executeProgram("bugpoint.reference.out");
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CreatedOutput = true;
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std::cout << " done! Reference output is: bugpoint.reference.out.\n";
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} else if (diffProgram(Output)) {
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std::cout << "\n*** Input program does not match reference diff!\n"
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<< " Must be problem with input source!\n";
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return false; // Problem found
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}
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// Figure out which transformations miscompile the input program.
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unsigned OldSize = PassesToRun.size();
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ReduceMiscompilingPasses(*this).reduceList(PassesToRun);
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// Make sure something was miscompiled...
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if (PassesToRun.size() == OldSize) {
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std::cerr << "*** Optimized program matches reference output! No problem "
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<< "detected...\nbugpoint can't help you with your problem!\n";
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return false;
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}
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std::cout << "\n*** Found miscompiling pass"
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<< (PassesToRun.size() == 1 ? "" : "es") << ": "
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<< getPassesString(PassesToRun) << "\n";
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EmitProgressBytecode("passinput");
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// Okay, now that we have reduced the list of passes which are causing the
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// failure, see if we can pin down which functions are being
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// miscompiled... first build a list of all of the non-external functions in
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// the program.
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std::vector<Function*> MiscompiledFunctions;
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for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
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if (!I->isExternal())
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MiscompiledFunctions.push_back(I);
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// Do the reduction...
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ReduceMiscompilingFunctions(*this).reduceList(MiscompiledFunctions);
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std::cout << "\n*** The following functions are being miscompiled: ";
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PrintFunctionList(MiscompiledFunctions);
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std::cout << "\n";
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// Output a bunch of bytecode files for the user...
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ReduceMiscompilingFunctions(*this).TestFuncs(MiscompiledFunctions, true);
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if (CreatedOutput) removeFile(Output);
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return false;
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}
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