1 //===- OptimizerDriver.cpp - Allow BugPoint to run passes safely ----------===//
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 file defines an interface that allows bugpoint to run various passes
11 // without the threat of a buggy pass corrupting bugpoint (of course, bugpoint
12 // may have its own bugs, but that's another story...).  It achieves this by
13 // forking a copy of itself and having the child process do the optimizations.
14 // If this client dies, we can always fork a new one.  :)
15 //
16 //===----------------------------------------------------------------------===//
17 
18 // Note: as a short term hack, the old Unix-specific code and platform-
19 // independent code co-exist via conditional compilation until it is verified
20 // that the new code works correctly on Unix.
21 
22 #include "BugDriver.h"
23 #include "llvm/Module.h"
24 #include "llvm/PassManager.h"
25 #include "llvm/Analysis/Verifier.h"
26 #include "llvm/Bitcode/ReaderWriter.h"
27 #include "llvm/Target/TargetData.h"
28 #include "llvm/Support/FileUtilities.h"
29 #include "llvm/Support/CommandLine.h"
30 #include "llvm/System/Path.h"
31 #include "llvm/System/Program.h"
32 #include "llvm/Config/alloca.h"
33 
34 #define DONT_GET_PLUGIN_LOADER_OPTION
35 #include "llvm/Support/PluginLoader.h"
36 
37 #include <fstream>
38 using namespace llvm;
39 
40 
41 namespace {
42   // ChildOutput - This option captures the name of the child output file that
43   // is set up by the parent bugpoint process
44   cl::opt<std::string> ChildOutput("child-output", cl::ReallyHidden);
45   cl::opt<bool> UseValgrind("enable-valgrind",
46                             cl::desc("Run optimizations through valgrind"));
47 }
48 
49 /// writeProgramToFile - This writes the current "Program" to the named bitcode
50 /// file.  If an error occurs, true is returned.
51 ///
52 bool BugDriver::writeProgramToFile(const std::string &Filename,
53                                    Module *M) const {
54   std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
55                                std::ios::binary;
56   std::ofstream Out(Filename.c_str(), io_mode);
57   if (!Out.good()) return true;
58 
59   WriteBitcodeToFile(M ? M : Program, Out);
60   return false;
61 }
62 
63 
64 /// EmitProgressBitcode - This function is used to output the current Program
65 /// to a file named "bugpoint-ID.bc".
66 ///
67 void BugDriver::EmitProgressBitcode(const std::string &ID, bool NoFlyer) {
68   // Output the input to the current pass to a bitcode file, emit a message
69   // telling the user how to reproduce it: opt -foo blah.bc
70   //
71   std::string Filename = "bugpoint-" + ID + ".bc";
72   if (writeProgramToFile(Filename)) {
73     errs() <<  "Error opening file '" << Filename << "' for writing!\n";
74     return;
75   }
76 
77   outs() << "Emitted bitcode to '" << Filename << "'\n";
78   if (NoFlyer || PassesToRun.empty()) return;
79   outs() << "\n*** You can reproduce the problem with: ";
80   outs() << "opt " << Filename << " ";
81   outs() << getPassesString(PassesToRun) << "\n";
82 }
83 
84 int BugDriver::runPassesAsChild(const std::vector<const PassInfo*> &Passes) {
85 
86   std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
87                                std::ios::binary;
88   std::ofstream OutFile(ChildOutput.c_str(), io_mode);
89   if (!OutFile.good()) {
90     errs() << "Error opening bitcode file: " << ChildOutput << "\n";
91     return 1;
92   }
93 
94   PassManager PM;
95   // Make sure that the appropriate target data is always used...
96   PM.add(new TargetData(Program));
97 
98   for (unsigned i = 0, e = Passes.size(); i != e; ++i) {
99     if (Passes[i]->getNormalCtor())
100       PM.add(Passes[i]->getNormalCtor()());
101     else
102       errs() << "Cannot create pass yet: " << Passes[i]->getPassName() << "\n";
103   }
104   // Check that the module is well formed on completion of optimization
105   PM.add(createVerifierPass());
106 
107   // Write bitcode out to disk as the last step...
108   PM.add(CreateBitcodeWriterPass(OutFile));
109 
110   // Run all queued passes.
111   PM.run(*Program);
112 
113   return 0;
114 }
115 
116 cl::opt<bool> SilencePasses("silence-passes", cl::desc("Suppress output of running passes (both stdout and stderr)"));
117 
118 /// runPasses - Run the specified passes on Program, outputting a bitcode file
119 /// and writing the filename into OutputFile if successful.  If the
120 /// optimizations fail for some reason (optimizer crashes), return true,
121 /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
122 /// deleted on success, and the filename string is undefined.  This prints to
123 /// outs() a single line message indicating whether compilation was successful
124 /// or failed.
125 ///
126 bool BugDriver::runPasses(const std::vector<const PassInfo*> &Passes,
127                           std::string &OutputFilename, bool DeleteOutput,
128                           bool Quiet, unsigned NumExtraArgs,
129                           const char * const *ExtraArgs) const {
130   // setup the output file name
131   outs().flush();
132   sys::Path uniqueFilename("bugpoint-output.bc");
133   std::string ErrMsg;
134   if (uniqueFilename.makeUnique(true, &ErrMsg)) {
135     errs() << getToolName() << ": Error making unique filename: "
136            << ErrMsg << "\n";
137     return(1);
138   }
139   OutputFilename = uniqueFilename.toString();
140 
141   // set up the input file name
142   sys::Path inputFilename("bugpoint-input.bc");
143   if (inputFilename.makeUnique(true, &ErrMsg)) {
144     errs() << getToolName() << ": Error making unique filename: "
145            << ErrMsg << "\n";
146     return(1);
147   }
148   std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
149                                std::ios::binary;
150   std::ofstream InFile(inputFilename.c_str(), io_mode);
151   if (!InFile.good()) {
152     errs() << "Error opening bitcode file: " << inputFilename << "\n";
153     return(1);
154   }
155   WriteBitcodeToFile(Program, InFile);
156   InFile.close();
157 
158   // setup the child process' arguments
159   const char** args = (const char**)
160     alloca(sizeof(const char*) *
161            (Passes.size()+13+2*PluginLoader::getNumPlugins()+NumExtraArgs));
162   int n = 0;
163   sys::Path tool = sys::Program::FindProgramByName(ToolName);
164   if (UseValgrind) {
165     args[n++] = "valgrind";
166     args[n++] = "--error-exitcode=1";
167     args[n++] = "-q";
168     args[n++] = tool.c_str();
169   } else
170     args[n++] = ToolName.c_str();
171 
172   args[n++] = "-as-child";
173   args[n++] = "-child-output";
174   args[n++] = OutputFilename.c_str();
175   std::vector<std::string> pass_args;
176   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
177     pass_args.push_back( std::string("-load"));
178     pass_args.push_back( PluginLoader::getPlugin(i));
179   }
180   for (std::vector<const PassInfo*>::const_iterator I = Passes.begin(),
181        E = Passes.end(); I != E; ++I )
182     pass_args.push_back( std::string("-") + (*I)->getPassArgument() );
183   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
184        E = pass_args.end(); I != E; ++I )
185     args[n++] = I->c_str();
186   args[n++] = inputFilename.c_str();
187   for (unsigned i = 0; i < NumExtraArgs; ++i)
188     args[n++] = *ExtraArgs;
189   args[n++] = 0;
190 
191   sys::Path prog;
192   if (UseValgrind)
193     prog = sys::Program::FindProgramByName("valgrind");
194   else
195     prog = tool;
196 
197   // Redirect stdout and stderr to nowhere if SilencePasses is given
198   sys::Path Nowhere;
199   const sys::Path *Redirects[3] = {0, &Nowhere, &Nowhere};
200 
201   int result = sys::Program::ExecuteAndWait(prog, args, 0, (SilencePasses ? Redirects : 0),
202                                             Timeout, MemoryLimit, &ErrMsg);
203 
204   // If we are supposed to delete the bitcode file or if the passes crashed,
205   // remove it now.  This may fail if the file was never created, but that's ok.
206   if (DeleteOutput || result != 0)
207     sys::Path(OutputFilename).eraseFromDisk();
208 
209   // Remove the temporary input file as well
210   inputFilename.eraseFromDisk();
211 
212   if (!Quiet) {
213     if (result == 0)
214       outs() << "Success!\n";
215     else if (result > 0)
216       outs() << "Exited with error code '" << result << "'\n";
217     else if (result < 0) {
218       if (result == -1)
219         outs() << "Execute failed: " << ErrMsg << "\n";
220       else
221         outs() << "Crashed with signal #" << abs(result) << "\n";
222     }
223     if (result & 0x01000000)
224       outs() << "Dumped core\n";
225   }
226 
227   // Was the child successful?
228   return result != 0;
229 }
230 
231 
232 /// runPassesOn - Carefully run the specified set of pass on the specified
233 /// module, returning the transformed module on success, or a null pointer on
234 /// failure.
235 Module *BugDriver::runPassesOn(Module *M,
236                                const std::vector<const PassInfo*> &Passes,
237                                bool AutoDebugCrashes, unsigned NumExtraArgs,
238                                const char * const *ExtraArgs) {
239   Module *OldProgram = swapProgramIn(M);
240   std::string BitcodeResult;
241   if (runPasses(Passes, BitcodeResult, false/*delete*/, true/*quiet*/,
242                 NumExtraArgs, ExtraArgs)) {
243     if (AutoDebugCrashes) {
244       errs() << " Error running this sequence of passes"
245              << " on the input program!\n";
246       delete OldProgram;
247       EmitProgressBitcode("pass-error",  false);
248       exit(debugOptimizerCrash());
249     }
250     swapProgramIn(OldProgram);
251     return 0;
252   }
253 
254   // Restore the current program.
255   swapProgramIn(OldProgram);
256 
257   Module *Ret = ParseInputFile(BitcodeResult, Context);
258   if (Ret == 0) {
259     errs() << getToolName() << ": Error reading bitcode file '"
260            << BitcodeResult << "'!\n";
261     exit(1);
262   }
263   sys::Path(BitcodeResult).eraseFromDisk();  // No longer need the file on disk
264   return Ret;
265 }
266