OptimizerDriver.cpp revision b515d75856f58a8b3b71d782eb00916d686329ad 
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>
38using namespace llvm;
39
40
41namespace {
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///
52bool BugDriver::writeProgramToFile(const std::string &Filename,
53                                   Module *M) const {
54  std::string ErrInfo;
55  raw_fd_ostream Out(Filename.c_str(), ErrInfo,
56                     raw_fd_ostream::F_Force|raw_fd_ostream::F_Binary);
57  if (!ErrInfo.empty()) 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///
67void 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  if (UseValgrind) outs() << "valgrind ";
81  outs() << "opt " << Filename << " ";
82  outs() << getPassesString(PassesToRun) << "\n";
83}
84
85int BugDriver::runPassesAsChild(const std::vector<const PassInfo*> &Passes) {
86  std::string ErrInfo;
87  raw_fd_ostream OutFile(ChildOutput.c_str(), ErrInfo,
88                         raw_fd_ostream::F_Force|raw_fd_ostream::F_Binary);
89  if (!ErrInfo.empty()) {
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
116cl::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///
126bool 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
149  std::string ErrInfo;
150  raw_fd_ostream InFile(inputFilename.c_str(), ErrInfo,
151                        raw_fd_ostream::F_Force|raw_fd_ostream::F_Binary);
152
153
154  if (!ErrInfo.empty()) {
155    errs() << "Error opening bitcode file: " << inputFilename << "\n";
156    return 1;
157  }
158  WriteBitcodeToFile(Program, InFile);
159  InFile.close();
160
161  // setup the child process' arguments
162  const char** args = (const char**)
163    alloca(sizeof(const char*) *
164           (Passes.size()+13+2*PluginLoader::getNumPlugins()+NumExtraArgs));
165  int n = 0;
166  sys::Path tool = sys::Program::FindProgramByName(ToolName);
167  if (UseValgrind) {
168    args[n++] = "valgrind";
169    args[n++] = "--error-exitcode=1";
170    args[n++] = "-q";
171    args[n++] = tool.c_str();
172  } else
173    args[n++] = ToolName;
174
175  args[n++] = "-as-child";
176  args[n++] = "-child-output";
177  args[n++] = OutputFilename.c_str();
178  std::vector<std::string> pass_args;
179  for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
180    pass_args.push_back( std::string("-load"));
181    pass_args.push_back( PluginLoader::getPlugin(i));
182  }
183  for (std::vector<const PassInfo*>::const_iterator I = Passes.begin(),
184       E = Passes.end(); I != E; ++I )
185    pass_args.push_back( std::string("-") + (*I)->getPassArgument() );
186  for (std::vector<std::string>::const_iterator I = pass_args.begin(),
187       E = pass_args.end(); I != E; ++I )
188    args[n++] = I->c_str();
189  args[n++] = inputFilename.c_str();
190  for (unsigned i = 0; i < NumExtraArgs; ++i)
191    args[n++] = *ExtraArgs;
192  args[n++] = 0;
193
194  sys::Path prog;
195  if (UseValgrind)
196    prog = sys::Program::FindProgramByName("valgrind");
197  else
198    prog = tool;
199
200  // Redirect stdout and stderr to nowhere if SilencePasses is given
201  sys::Path Nowhere;
202  const sys::Path *Redirects[3] = {0, &Nowhere, &Nowhere};
203
204  int result = sys::Program::ExecuteAndWait(prog, args, 0, (SilencePasses ? Redirects : 0),
205                                            Timeout, MemoryLimit, &ErrMsg);
206
207  // If we are supposed to delete the bitcode file or if the passes crashed,
208  // remove it now.  This may fail if the file was never created, but that's ok.
209  if (DeleteOutput || result != 0)
210    sys::Path(OutputFilename).eraseFromDisk();
211
212  // Remove the temporary input file as well
213  inputFilename.eraseFromDisk();
214
215  if (!Quiet) {
216    if (result == 0)
217      outs() << "Success!\n";
218    else if (result > 0)
219      outs() << "Exited with error code '" << result << "'\n";
220    else if (result < 0) {
221      if (result == -1)
222        outs() << "Execute failed: " << ErrMsg << "\n";
223      else
224        outs() << "Crashed with signal #" << abs(result) << "\n";
225    }
226    if (result & 0x01000000)
227      outs() << "Dumped core\n";
228  }
229
230  // Was the child successful?
231  return result != 0;
232}
233
234
235/// runPassesOn - Carefully run the specified set of pass on the specified
236/// module, returning the transformed module on success, or a null pointer on
237/// failure.
238Module *BugDriver::runPassesOn(Module *M,
239                               const std::vector<const PassInfo*> &Passes,
240                               bool AutoDebugCrashes, unsigned NumExtraArgs,
241                               const char * const *ExtraArgs) {
242  Module *OldProgram = swapProgramIn(M);
243  std::string BitcodeResult;
244  if (runPasses(Passes, BitcodeResult, false/*delete*/, true/*quiet*/,
245                NumExtraArgs, ExtraArgs)) {
246    if (AutoDebugCrashes) {
247      errs() << " Error running this sequence of passes"
248             << " on the input program!\n";
249      delete OldProgram;
250      EmitProgressBitcode("pass-error",  false);
251      exit(debugOptimizerCrash());
252    }
253    swapProgramIn(OldProgram);
254    return 0;
255  }
256
257  // Restore the current program.
258  swapProgramIn(OldProgram);
259
260  Module *Ret = ParseInputFile(BitcodeResult, Context);
261  if (Ret == 0) {
262    errs() << getToolName() << ": Error reading bitcode file '"
263           << BitcodeResult << "'!\n";
264    exit(1);
265  }
266  sys::Path(BitcodeResult).eraseFromDisk();  // No longer need the file on disk
267  return Ret;
268}
269