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#include "BugDriver.h"
19#include "llvm/Bitcode/ReaderWriter.h"
20#include "llvm/IR/DataLayout.h"
21#include "llvm/IR/Module.h"
22#include "llvm/IR/Verifier.h"
23#include "llvm/PassManager.h"
24#include "llvm/Support/CommandLine.h"
25#include "llvm/Support/Debug.h"
26#include "llvm/Support/FileUtilities.h"
27#include "llvm/Support/Path.h"
28#include "llvm/Support/Program.h"
29#include "llvm/Support/SystemUtils.h"
30#include "llvm/Support/ToolOutputFile.h"
31
32#define DONT_GET_PLUGIN_LOADER_OPTION
33#include "llvm/Support/PluginLoader.h"
34
35#include <fstream>
36
37using namespace llvm;
38
39#define DEBUG_TYPE "bugpoint"
40
41namespace llvm {
42  extern cl::opt<std::string> OutputPrefix;
43}
44
45namespace {
46  // ChildOutput - This option captures the name of the child output file that
47  // is set up by the parent bugpoint process
48  cl::opt<std::string> ChildOutput("child-output", cl::ReallyHidden);
49  cl::opt<std::string> OptCmd("opt-command", cl::init(""),
50                              cl::desc("Path to opt. (default: search path "
51                                       "for 'opt'.)"));
52}
53
54/// writeProgramToFile - This writes the current "Program" to the named bitcode
55/// file.  If an error occurs, true is returned.
56///
57static bool writeProgramToFileAux(tool_output_file &Out, const Module *M) {
58  WriteBitcodeToFile(M, Out.os());
59  Out.os().close();
60  if (!Out.os().has_error()) {
61    Out.keep();
62    return false;
63  }
64  return true;
65}
66
67bool BugDriver::writeProgramToFile(const std::string &Filename, int FD,
68                                   const Module *M) const {
69  tool_output_file Out(Filename.c_str(), FD);
70  return writeProgramToFileAux(Out, M);
71}
72
73bool BugDriver::writeProgramToFile(const std::string &Filename,
74                                   const Module *M) const {
75  std::string ErrInfo;
76  tool_output_file Out(Filename.c_str(), ErrInfo, sys::fs::F_None);
77  if (ErrInfo.empty())
78    return writeProgramToFileAux(Out, M);
79  return true;
80}
81
82
83/// EmitProgressBitcode - This function is used to output the current Program
84/// to a file named "bugpoint-ID.bc".
85///
86void BugDriver::EmitProgressBitcode(const Module *M,
87                                    const std::string &ID,
88                                    bool NoFlyer)  const {
89  // Output the input to the current pass to a bitcode file, emit a message
90  // telling the user how to reproduce it: opt -foo blah.bc
91  //
92  std::string Filename = OutputPrefix + "-" + ID + ".bc";
93  if (writeProgramToFile(Filename, M)) {
94    errs() <<  "Error opening file '" << Filename << "' for writing!\n";
95    return;
96  }
97
98  outs() << "Emitted bitcode to '" << Filename << "'\n";
99  if (NoFlyer || PassesToRun.empty()) return;
100  outs() << "\n*** You can reproduce the problem with: ";
101  if (UseValgrind) outs() << "valgrind ";
102  outs() << "opt " << Filename;
103  for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
104    outs() << " -load " << PluginLoader::getPlugin(i);
105  }
106  outs() << " " << getPassesString(PassesToRun) << "\n";
107}
108
109cl::opt<bool> SilencePasses("silence-passes",
110        cl::desc("Suppress output of running passes (both stdout and stderr)"));
111
112static cl::list<std::string> OptArgs("opt-args", cl::Positional,
113                                     cl::desc("<opt arguments>..."),
114                                     cl::ZeroOrMore, cl::PositionalEatsArgs);
115
116/// runPasses - Run the specified passes on Program, outputting a bitcode file
117/// and writing the filename into OutputFile if successful.  If the
118/// optimizations fail for some reason (optimizer crashes), return true,
119/// otherwise return false.  If DeleteOutput is set to true, the bitcode is
120/// deleted on success, and the filename string is undefined.  This prints to
121/// outs() a single line message indicating whether compilation was successful
122/// or failed.
123///
124bool BugDriver::runPasses(Module *Program,
125                          const std::vector<std::string> &Passes,
126                          std::string &OutputFilename, bool DeleteOutput,
127                          bool Quiet, unsigned NumExtraArgs,
128                          const char * const *ExtraArgs) const {
129  // setup the output file name
130  outs().flush();
131  SmallString<128> UniqueFilename;
132  std::error_code EC = sys::fs::createUniqueFile(
133      OutputPrefix + "-output-%%%%%%%.bc", UniqueFilename);
134  if (EC) {
135    errs() << getToolName() << ": Error making unique filename: "
136           << EC.message() << "\n";
137    return 1;
138  }
139  OutputFilename = UniqueFilename.str();
140
141  // set up the input file name
142  SmallString<128> InputFilename;
143  int InputFD;
144  EC = sys::fs::createUniqueFile(OutputPrefix + "-input-%%%%%%%.bc", InputFD,
145                                 InputFilename);
146  if (EC) {
147    errs() << getToolName() << ": Error making unique filename: "
148           << EC.message() << "\n";
149    return 1;
150  }
151
152  tool_output_file InFile(InputFilename.c_str(), InputFD);
153
154  WriteBitcodeToFile(Program, InFile.os());
155  InFile.os().close();
156  if (InFile.os().has_error()) {
157    errs() << "Error writing bitcode file: " << InputFilename << "\n";
158    InFile.os().clear_error();
159    return 1;
160  }
161
162  std::string tool = OptCmd.empty()? sys::FindProgramByName("opt") : OptCmd;
163  if (tool.empty()) {
164    errs() << "Cannot find `opt' in PATH!\n";
165    return 1;
166  }
167
168  // Ok, everything that could go wrong before running opt is done.
169  InFile.keep();
170
171  // setup the child process' arguments
172  SmallVector<const char*, 8> Args;
173  if (UseValgrind) {
174    Args.push_back("valgrind");
175    Args.push_back("--error-exitcode=1");
176    Args.push_back("-q");
177    Args.push_back(tool.c_str());
178  } else
179    Args.push_back(tool.c_str());
180
181  Args.push_back("-o");
182  Args.push_back(OutputFilename.c_str());
183  for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
184    Args.push_back(OptArgs[i].c_str());
185  std::vector<std::string> pass_args;
186  for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
187    pass_args.push_back( std::string("-load"));
188    pass_args.push_back( PluginLoader::getPlugin(i));
189  }
190  for (std::vector<std::string>::const_iterator I = Passes.begin(),
191       E = Passes.end(); I != E; ++I )
192    pass_args.push_back( std::string("-") + (*I) );
193  for (std::vector<std::string>::const_iterator I = pass_args.begin(),
194       E = pass_args.end(); I != E; ++I )
195    Args.push_back(I->c_str());
196  Args.push_back(InputFilename.c_str());
197  for (unsigned i = 0; i < NumExtraArgs; ++i)
198    Args.push_back(*ExtraArgs);
199  Args.push_back(nullptr);
200
201  DEBUG(errs() << "\nAbout to run:\t";
202        for (unsigned i = 0, e = Args.size()-1; i != e; ++i)
203          errs() << " " << Args[i];
204        errs() << "\n";
205        );
206
207  std::string Prog;
208  if (UseValgrind)
209    Prog = sys::FindProgramByName("valgrind");
210  else
211    Prog = tool;
212
213  // Redirect stdout and stderr to nowhere if SilencePasses is given
214  StringRef Nowhere;
215  const StringRef *Redirects[3] = {nullptr, &Nowhere, &Nowhere};
216
217  std::string ErrMsg;
218  int result = sys::ExecuteAndWait(Prog, Args.data(), nullptr,
219                                   (SilencePasses ? Redirects : nullptr),
220                                   Timeout, MemoryLimit, &ErrMsg);
221
222  // If we are supposed to delete the bitcode file or if the passes crashed,
223  // remove it now.  This may fail if the file was never created, but that's ok.
224  if (DeleteOutput || result != 0)
225    sys::fs::remove(OutputFilename);
226
227  // Remove the temporary input file as well
228  sys::fs::remove(InputFilename.c_str());
229
230  if (!Quiet) {
231    if (result == 0)
232      outs() << "Success!\n";
233    else if (result > 0)
234      outs() << "Exited with error code '" << result << "'\n";
235    else if (result < 0) {
236      if (result == -1)
237        outs() << "Execute failed: " << ErrMsg << "\n";
238      else
239        outs() << "Crashed: " << ErrMsg << "\n";
240    }
241    if (result & 0x01000000)
242      outs() << "Dumped core\n";
243  }
244
245  // Was the child successful?
246  return result != 0;
247}
248
249
250/// runPassesOn - Carefully run the specified set of pass on the specified
251/// module, returning the transformed module on success, or a null pointer on
252/// failure.
253Module *BugDriver::runPassesOn(Module *M,
254                               const std::vector<std::string> &Passes,
255                               bool AutoDebugCrashes, unsigned NumExtraArgs,
256                               const char * const *ExtraArgs) {
257  std::string BitcodeResult;
258  if (runPasses(M, Passes, BitcodeResult, false/*delete*/, true/*quiet*/,
259                NumExtraArgs, ExtraArgs)) {
260    if (AutoDebugCrashes) {
261      errs() << " Error running this sequence of passes"
262             << " on the input program!\n";
263      delete swapProgramIn(M);
264      EmitProgressBitcode(M, "pass-error",  false);
265      exit(debugOptimizerCrash());
266    }
267    return nullptr;
268  }
269
270  Module *Ret = ParseInputFile(BitcodeResult, Context);
271  if (!Ret) {
272    errs() << getToolName() << ": Error reading bitcode file '"
273           << BitcodeResult << "'!\n";
274    exit(1);
275  }
276  sys::fs::remove(BitcodeResult);
277  return Ret;
278}
279