OptimizerDriver.cpp revision 8b477ed579794ba6d76915d56b3f448a7dd20120 
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/Support/Streams.h"
31#include "llvm/System/Path.h"
32#include "llvm/System/Program.h"
33#include "llvm/Config/alloca.h"
34
35#define DONT_GET_PLUGIN_LOADER_OPTION
36#include "llvm/Support/PluginLoader.h"
37
38#include <fstream>
39using namespace llvm;
40
41
42namespace {
43  // ChildOutput - This option captures the name of the child output file that
44  // is set up by the parent bugpoint process
45  cl::opt<std::string> ChildOutput("child-output", cl::ReallyHidden);
46  cl::opt<bool> UseValgrind("enable-valgrind",
47                            cl::desc("Run optimizations through valgrind"));
48}
49
50/// writeProgramToFile - This writes the current "Program" to the named bitcode
51/// file.  If an error occurs, true is returned.
52///
53bool BugDriver::writeProgramToFile(const std::string &Filename,
54                                   Module *M) const {
55  std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
56                               std::ios::binary;
57  std::ofstream Out(Filename.c_str(), io_mode);
58  if (!Out.good()) return true;
59
60  WriteBitcodeToFile(M ? M : Program, Out);
61  return false;
62}
63
64
65/// EmitProgressBitcode - This function is used to output the current Program
66/// to a file named "bugpoint-ID.bc".
67///
68void BugDriver::EmitProgressBitcode(const std::string &ID, bool NoFlyer) {
69  // Output the input to the current pass to a bitcode file, emit a message
70  // telling the user how to reproduce it: opt -foo blah.bc
71  //
72  std::string Filename = "bugpoint-" + ID + ".bc";
73  if (writeProgramToFile(Filename)) {
74    cerr <<  "Error opening file '" << Filename << "' for writing!\n";
75    return;
76  }
77
78  cout << "Emitted bitcode to '" << Filename << "'\n";
79  if (NoFlyer || PassesToRun.empty()) return;
80  cout << "\n*** You can reproduce the problem with: ";
81  cout << "opt " << Filename << " ";
82  cout << getPassesString(PassesToRun) << "\n";
83}
84
85int BugDriver::runPassesAsChild(const std::vector<const PassInfo*> &Passes) {
86
87  std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
88                               std::ios::binary;
89  std::ofstream OutFile(ChildOutput.c_str(), io_mode);
90  if (!OutFile.good()) {
91    cerr << "Error opening bitcode file: " << ChildOutput << "\n";
92    return 1;
93  }
94
95  PassManager PM;
96  // Make sure that the appropriate target data is always used...
97  PM.add(new TargetData(Program));
98
99  for (unsigned i = 0, e = Passes.size(); i != e; ++i) {
100    if (Passes[i]->getNormalCtor())
101      PM.add(Passes[i]->getNormalCtor()());
102    else
103      cerr << "Cannot create pass yet: " << Passes[i]->getPassName() << "\n";
104  }
105  // Check that the module is well formed on completion of optimization
106  PM.add(createVerifierPass());
107
108  // Write bitcode out to disk as the last step...
109  PM.add(CreateBitcodeWriterPass(OutFile));
110
111  // Run all queued passes.
112  PM.run(*Program);
113
114  return 0;
115}
116
117cl::opt<bool> SilencePasses("silence-passes", cl::desc("Suppress output of running passes (both stdout and stderr)"));
118
119/// runPasses - Run the specified passes on Program, outputting a bitcode file
120/// and writing the filename into OutputFile if successful.  If the
121/// optimizations fail for some reason (optimizer crashes), return true,
122/// otherwise return false.  If DeleteOutput is set to true, the bitcode is
123/// deleted on success, and the filename string is undefined.  This prints to
124/// cout a single line message indicating whether compilation was successful or
125/// failed.
126///
127bool BugDriver::runPasses(const std::vector<const PassInfo*> &Passes,
128                          std::string &OutputFilename, bool DeleteOutput,
129                          bool Quiet, unsigned NumExtraArgs,
130                          const char * const *ExtraArgs) const {
131  // setup the output file name
132  cout << std::flush;
133  sys::Path uniqueFilename("bugpoint-output.bc");
134  std::string ErrMsg;
135  if (uniqueFilename.makeUnique(true, &ErrMsg)) {
136    cerr << getToolName() << ": Error making unique filename: "
137         << ErrMsg << "\n";
138    return(1);
139  }
140  OutputFilename = uniqueFilename.toString();
141
142  // set up the input file name
143  sys::Path inputFilename("bugpoint-input.bc");
144  if (inputFilename.makeUnique(true, &ErrMsg)) {
145    cerr << getToolName() << ": Error making unique filename: "
146         << ErrMsg << "\n";
147    return(1);
148  }
149  std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
150                               std::ios::binary;
151  std::ofstream InFile(inputFilename.c_str(), io_mode);
152  if (!InFile.good()) {
153    cerr << "Error opening bitcode file: " << inputFilename << "\n";
154    return(1);
155  }
156  WriteBitcodeToFile(Program, InFile);
157  InFile.close();
158
159  // setup the child process' arguments
160  const char** args = (const char**)
161    alloca(sizeof(const char*) *
162           (Passes.size()+13+2*PluginLoader::getNumPlugins()+NumExtraArgs));
163  int n = 0;
164  sys::Path tool = sys::Program::FindProgramByName(ToolName);
165  if (UseValgrind) {
166    args[n++] = "valgrind";
167    args[n++] = "--error-exitcode=1";
168    args[n++] = "-q";
169    args[n++] = tool.c_str();
170  } else
171    args[n++] = ToolName.c_str();
172
173  args[n++] = "-as-child";
174  args[n++] = "-child-output";
175  args[n++] = OutputFilename.c_str();
176  std::vector<std::string> pass_args;
177  for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
178    pass_args.push_back( std::string("-load"));
179    pass_args.push_back( PluginLoader::getPlugin(i));
180  }
181  for (std::vector<const PassInfo*>::const_iterator I = Passes.begin(),
182       E = Passes.end(); I != E; ++I )
183    pass_args.push_back( std::string("-") + (*I)->getPassArgument() );
184  for (std::vector<std::string>::const_iterator I = pass_args.begin(),
185       E = pass_args.end(); I != E; ++I )
186    args[n++] = I->c_str();
187  args[n++] = inputFilename.c_str();
188  for (unsigned i = 0; i < NumExtraArgs; ++i)
189    args[n++] = *ExtraArgs;
190  args[n++] = 0;
191
192  sys::Path prog;
193  if (UseValgrind)
194    prog = sys::Program::FindProgramByName("valgrind");
195  else
196    prog = tool;
197
198  // Redirect stdout and stderr to nowhere if SilencePasses is given
199  sys::Path Nowhere;
200  const sys::Path *Redirects[3] = {0, &Nowhere, &Nowhere};
201
202  int result = sys::Program::ExecuteAndWait(prog, args, 0, (SilencePasses ? Redirects : 0),
203                                            Timeout, MemoryLimit, &ErrMsg);
204
205  // If we are supposed to delete the bitcode file or if the passes crashed,
206  // remove it now.  This may fail if the file was never created, but that's ok.
207  if (DeleteOutput || result != 0)
208    sys::Path(OutputFilename).eraseFromDisk();
209
210  // Remove the temporary input file as well
211  inputFilename.eraseFromDisk();
212
213  if (!Quiet) {
214    if (result == 0)
215      cout << "Success!\n";
216    else if (result > 0)
217      cout << "Exited with error code '" << result << "'\n";
218    else if (result < 0) {
219      if (result == -1)
220        cout << "Execute failed: " << ErrMsg << "\n";
221      else
222        cout << "Crashed with signal #" << abs(result) << "\n";
223    }
224    if (result & 0x01000000)
225      cout << "Dumped core\n";
226  }
227
228  // Was the child successful?
229  return result != 0;
230}
231
232
233/// runPassesOn - Carefully run the specified set of pass on the specified
234/// module, returning the transformed module on success, or a null pointer on
235/// failure.
236Module *BugDriver::runPassesOn(Module *M,
237                               const std::vector<const PassInfo*> &Passes,
238                               bool AutoDebugCrashes, unsigned NumExtraArgs,
239                               const char * const *ExtraArgs) {
240  Module *OldProgram = swapProgramIn(M);
241  std::string BitcodeResult;
242  if (runPasses(Passes, BitcodeResult, false/*delete*/, true/*quiet*/,
243                NumExtraArgs, ExtraArgs)) {
244    if (AutoDebugCrashes) {
245      cerr << " Error running this sequence of passes"
246           << " on the input program!\n";
247      delete OldProgram;
248      EmitProgressBitcode("pass-error",  false);
249      exit(debugOptimizerCrash());
250    }
251    swapProgramIn(OldProgram);
252    return 0;
253  }
254
255  // Restore the current program.
256  swapProgramIn(OldProgram);
257
258  Module *Ret = ParseInputFile(BitcodeResult, Context);
259  if (Ret == 0) {
260    cerr << getToolName() << ": Error reading bitcode file '"
261         << BitcodeResult << "'!\n";
262    exit(1);
263  }
264  sys::Path(BitcodeResult).eraseFromDisk();  // No longer need the file on disk
265  return Ret;
266}
267