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1 //===- BugDriver.cpp - Top-Level BugPoint class implementation ------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This class contains all of the shared state and information that is used by
11 // the BugPoint tool to track down errors in optimizations.  This class is the
12 // main driver class that invokes all sub-functionality.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "BugDriver.h"
17 #include "ToolRunner.h"
18 #include "llvm/Linker.h"
19 #include "llvm/Module.h"
20 #include "llvm/Pass.h"
21 #include "llvm/Support/IRReader.h"
22 #include "llvm/Support/CommandLine.h"
23 #include "llvm/Support/FileUtilities.h"
24 #include "llvm/Support/SourceMgr.h"
25 #include "llvm/Support/raw_ostream.h"
26 #include "llvm/Support/Host.h"
27 #include <memory>
28 using namespace llvm;
29 
30 namespace llvm {
31   Triple TargetTriple;
32 }
33 
34 // Anonymous namespace to define command line options for debugging.
35 //
36 namespace {
37   // Output - The user can specify a file containing the expected output of the
38   // program.  If this filename is set, it is used as the reference diff source,
39   // otherwise the raw input run through an interpreter is used as the reference
40   // source.
41   //
42   cl::opt<std::string>
43   OutputFile("output", cl::desc("Specify a reference program output "
44                                 "(for miscompilation detection)"));
45 }
46 
47 /// setNewProgram - If we reduce or update the program somehow, call this method
48 /// to update bugdriver with it.  This deletes the old module and sets the
49 /// specified one as the current program.
setNewProgram(Module * M)50 void BugDriver::setNewProgram(Module *M) {
51   delete Program;
52   Program = M;
53 }
54 
55 
56 /// getPassesString - Turn a list of passes into a string which indicates the
57 /// command line options that must be passed to add the passes.
58 ///
getPassesString(const std::vector<std::string> & Passes)59 std::string llvm::getPassesString(const std::vector<std::string> &Passes) {
60   std::string Result;
61   for (unsigned i = 0, e = Passes.size(); i != e; ++i) {
62     if (i) Result += " ";
63     Result += "-";
64     Result += Passes[i];
65   }
66   return Result;
67 }
68 
BugDriver(const char * toolname,bool find_bugs,unsigned timeout,unsigned memlimit,bool use_valgrind,LLVMContext & ctxt)69 BugDriver::BugDriver(const char *toolname, bool find_bugs,
70                      unsigned timeout, unsigned memlimit, bool use_valgrind,
71                      LLVMContext& ctxt)
72   : Context(ctxt), ToolName(toolname), ReferenceOutputFile(OutputFile),
73     Program(0), Interpreter(0), SafeInterpreter(0), gcc(0),
74     run_find_bugs(find_bugs), Timeout(timeout),
75     MemoryLimit(memlimit), UseValgrind(use_valgrind) {}
76 
~BugDriver()77 BugDriver::~BugDriver() {
78   delete Program;
79 }
80 
81 
82 /// ParseInputFile - Given a bitcode or assembly input filename, parse and
83 /// return it, or return null if not possible.
84 ///
ParseInputFile(const std::string & Filename,LLVMContext & Ctxt)85 Module *llvm::ParseInputFile(const std::string &Filename,
86                              LLVMContext& Ctxt) {
87   SMDiagnostic Err;
88   Module *Result = ParseIRFile(Filename, Err, Ctxt);
89   if (!Result)
90     Err.Print("bugpoint", errs());
91 
92   // If we don't have an override triple, use the first one to configure
93   // bugpoint, or use the host triple if none provided.
94   if (Result) {
95     if (TargetTriple.getTriple().empty()) {
96       Triple TheTriple(Result->getTargetTriple());
97 
98       if (TheTriple.getTriple().empty())
99         TheTriple.setTriple(sys::getHostTriple());
100 
101       TargetTriple.setTriple(TheTriple.getTriple());
102     }
103 
104     Result->setTargetTriple(TargetTriple.getTriple());  // override the triple
105   }
106   return Result;
107 }
108 
109 // This method takes the specified list of LLVM input files, attempts to load
110 // them, either as assembly or bitcode, then link them together. It returns
111 // true on failure (if, for example, an input bitcode file could not be
112 // parsed), and false on success.
113 //
addSources(const std::vector<std::string> & Filenames)114 bool BugDriver::addSources(const std::vector<std::string> &Filenames) {
115   assert(Program == 0 && "Cannot call addSources multiple times!");
116   assert(!Filenames.empty() && "Must specify at least on input filename!");
117 
118   // Load the first input file.
119   Program = ParseInputFile(Filenames[0], Context);
120   if (Program == 0) return true;
121 
122   outs() << "Read input file      : '" << Filenames[0] << "'\n";
123 
124   for (unsigned i = 1, e = Filenames.size(); i != e; ++i) {
125     std::auto_ptr<Module> M(ParseInputFile(Filenames[i], Context));
126     if (M.get() == 0) return true;
127 
128     outs() << "Linking in input file: '" << Filenames[i] << "'\n";
129     std::string ErrorMessage;
130     if (Linker::LinkModules(Program, M.get(), &ErrorMessage)) {
131       errs() << ToolName << ": error linking in '" << Filenames[i] << "': "
132              << ErrorMessage << '\n';
133       return true;
134     }
135   }
136 
137   outs() << "*** All input ok\n";
138 
139   // All input files read successfully!
140   return false;
141 }
142 
143 
144 
145 /// run - The top level method that is invoked after all of the instance
146 /// variables are set up from command line arguments.
147 ///
run(std::string & ErrMsg)148 bool BugDriver::run(std::string &ErrMsg) {
149   if (run_find_bugs) {
150     // Rearrange the passes and apply them to the program. Repeat this process
151     // until the user kills the program or we find a bug.
152     return runManyPasses(PassesToRun, ErrMsg);
153   }
154 
155   // If we're not running as a child, the first thing that we must do is
156   // determine what the problem is. Does the optimization series crash the
157   // compiler, or does it produce illegal code?  We make the top-level
158   // decision by trying to run all of the passes on the the input program,
159   // which should generate a bitcode file.  If it does generate a bitcode
160   // file, then we know the compiler didn't crash, so try to diagnose a
161   // miscompilation.
162   if (!PassesToRun.empty()) {
163     outs() << "Running selected passes on program to test for crash: ";
164     if (runPasses(Program, PassesToRun))
165       return debugOptimizerCrash();
166   }
167 
168   // Set up the execution environment, selecting a method to run LLVM bitcode.
169   if (initializeExecutionEnvironment()) return true;
170 
171   // Test to see if we have a code generator crash.
172   outs() << "Running the code generator to test for a crash: ";
173   std::string Error;
174   compileProgram(Program, &Error);
175   if (!Error.empty()) {
176     outs() << Error;
177     return debugCodeGeneratorCrash(ErrMsg);
178   }
179   outs() << '\n';
180 
181   // Run the raw input to see where we are coming from.  If a reference output
182   // was specified, make sure that the raw output matches it.  If not, it's a
183   // problem in the front-end or the code generator.
184   //
185   bool CreatedOutput = false;
186   if (ReferenceOutputFile.empty()) {
187     outs() << "Generating reference output from raw program: ";
188     if (!createReferenceFile(Program)) {
189       return debugCodeGeneratorCrash(ErrMsg);
190     }
191     CreatedOutput = true;
192   }
193 
194   // Make sure the reference output file gets deleted on exit from this
195   // function, if appropriate.
196   sys::Path ROF(ReferenceOutputFile);
197   FileRemover RemoverInstance(ROF.str(), CreatedOutput && !SaveTemps);
198 
199   // Diff the output of the raw program against the reference output.  If it
200   // matches, then we assume there is a miscompilation bug and try to
201   // diagnose it.
202   outs() << "*** Checking the code generator...\n";
203   bool Diff = diffProgram(Program, "", "", false, &Error);
204   if (!Error.empty()) {
205     errs() << Error;
206     return debugCodeGeneratorCrash(ErrMsg);
207   }
208   if (!Diff) {
209     outs() << "\n*** Output matches: Debugging miscompilation!\n";
210     debugMiscompilation(&Error);
211     if (!Error.empty()) {
212       errs() << Error;
213       return debugCodeGeneratorCrash(ErrMsg);
214     }
215     return false;
216   }
217 
218   outs() << "\n*** Input program does not match reference diff!\n";
219   outs() << "Debugging code generator problem!\n";
220   bool Failure = debugCodeGenerator(&Error);
221   if (!Error.empty()) {
222     errs() << Error;
223     return debugCodeGeneratorCrash(ErrMsg);
224   }
225   return Failure;
226 }
227 
PrintFunctionList(const std::vector<Function * > & Funcs)228 void llvm::PrintFunctionList(const std::vector<Function*> &Funcs) {
229   unsigned NumPrint = Funcs.size();
230   if (NumPrint > 10) NumPrint = 10;
231   for (unsigned i = 0; i != NumPrint; ++i)
232     outs() << " " << Funcs[i]->getName();
233   if (NumPrint < Funcs.size())
234     outs() << "... <" << Funcs.size() << " total>";
235   outs().flush();
236 }
237 
PrintGlobalVariableList(const std::vector<GlobalVariable * > & GVs)238 void llvm::PrintGlobalVariableList(const std::vector<GlobalVariable*> &GVs) {
239   unsigned NumPrint = GVs.size();
240   if (NumPrint > 10) NumPrint = 10;
241   for (unsigned i = 0; i != NumPrint; ++i)
242     outs() << " " << GVs[i]->getName();
243   if (NumPrint < GVs.size())
244     outs() << "... <" << GVs.size() << " total>";
245   outs().flush();
246 }
247