OptimizerDriver.cpp revision 360784 
1//===- OptimizerDriver.cpp - Allow BugPoint to run passes safely ----------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines an interface that allows bugpoint to run various passes
10// without the threat of a buggy pass corrupting bugpoint (of course, bugpoint
11// may have its own bugs, but that's another story...).  It achieves this by
12// forking a copy of itself and having the child process do the optimizations.
13// If this client dies, we can always fork a new one.  :)
14//
15//===----------------------------------------------------------------------===//
16
17#include "BugDriver.h"
18#include "ToolRunner.h"
19#include "llvm/Bitcode/BitcodeWriter.h"
20#include "llvm/IR/DataLayout.h"
21#include "llvm/IR/Module.h"
22#include "llvm/Support/CommandLine.h"
23#include "llvm/Support/Debug.h"
24#include "llvm/Support/FileUtilities.h"
25#include "llvm/Support/Path.h"
26#include "llvm/Support/Program.h"
27#include "llvm/Support/ToolOutputFile.h"
28
29#define DONT_GET_PLUGIN_LOADER_OPTION
30#include "llvm/Support/PluginLoader.h"
31
32
33using namespace llvm;
34
35#define DEBUG_TYPE "bugpoint"
36
37namespace llvm {
38extern cl::opt<std::string> OutputPrefix;
39}
40
41static cl::opt<bool> PreserveBitcodeUseListOrder(
42    "preserve-bc-uselistorder",
43    cl::desc("Preserve use-list order when writing LLVM bitcode."),
44    cl::init(true), cl::Hidden);
45
46static cl::opt<std::string>
47    OptCmd("opt-command", cl::init(""),
48           cl::desc("Path to opt. (default: search path "
49                    "for 'opt'.)"));
50
51/// This writes the current "Program" to the named bitcode file.  If an error
52/// occurs, true is returned.
53static bool writeProgramToFileAux(ToolOutputFile &Out, const Module &M) {
54  WriteBitcodeToFile(M, Out.os(), PreserveBitcodeUseListOrder);
55  Out.os().close();
56  if (!Out.os().has_error()) {
57    Out.keep();
58    return false;
59  }
60  return true;
61}
62
63bool BugDriver::writeProgramToFile(const std::string &Filename, int FD,
64                                   const Module &M) const {
65  ToolOutputFile Out(Filename, FD);
66  return writeProgramToFileAux(Out, M);
67}
68
69bool BugDriver::writeProgramToFile(int FD, const Module &M) const {
70  raw_fd_ostream OS(FD, /*shouldClose*/ false);
71  WriteBitcodeToFile(M, OS, PreserveBitcodeUseListOrder);
72  OS.flush();
73  if (!OS.has_error())
74    return false;
75  OS.clear_error();
76  return true;
77}
78
79bool BugDriver::writeProgramToFile(const std::string &Filename,
80                                   const Module &M) const {
81  std::error_code EC;
82  ToolOutputFile Out(Filename, EC, sys::fs::OF_None);
83  if (!EC)
84    return writeProgramToFileAux(Out, M);
85  return true;
86}
87
88/// This function is used to output the current Program to a file named
89/// "bugpoint-ID.bc".
90void BugDriver::EmitProgressBitcode(const Module &M, const std::string &ID,
91                                    bool NoFlyer) const {
92  // Output the input to the current pass to a bitcode file, emit a message
93  // telling the user how to reproduce it: opt -foo blah.bc
94  //
95  std::string Filename = OutputPrefix + "-" + ID + ".bc";
96  if (writeProgramToFile(Filename, M)) {
97    errs() << "Error opening file '" << Filename << "' for writing!\n";
98    return;
99  }
100
101  outs() << "Emitted bitcode to '" << Filename << "'\n";
102  if (NoFlyer || PassesToRun.empty())
103    return;
104  outs() << "\n*** You can reproduce the problem with: ";
105  if (UseValgrind)
106    outs() << "valgrind ";
107  outs() << "opt " << Filename;
108  for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
109    outs() << " -load " << PluginLoader::getPlugin(i);
110  }
111  outs() << " " << getPassesString(PassesToRun) << "\n";
112}
113
114cl::opt<bool> SilencePasses(
115    "silence-passes",
116    cl::desc("Suppress output of running passes (both stdout and stderr)"));
117
118static cl::list<std::string> OptArgs("opt-args", cl::Positional,
119                                     cl::desc("<opt arguments>..."),
120                                     cl::ZeroOrMore, cl::PositionalEatsArgs);
121
122/// runPasses - Run the specified passes on Program, outputting a bitcode file
123/// and writing the filename into OutputFile if successful.  If the
124/// optimizations fail for some reason (optimizer crashes), return true,
125/// otherwise return false.  If DeleteOutput is set to true, the bitcode is
126/// deleted on success, and the filename string is undefined.  This prints to
127/// outs() a single line message indicating whether compilation was successful
128/// or failed.
129///
130bool BugDriver::runPasses(Module &Program,
131                          const std::vector<std::string> &Passes,
132                          std::string &OutputFilename, bool DeleteOutput,
133                          bool Quiet, ArrayRef<std::string> ExtraArgs) const {
134  // setup the output file name
135  outs().flush();
136  SmallString<128> UniqueFilename;
137  std::error_code EC = sys::fs::createUniqueFile(
138      OutputPrefix + "-output-%%%%%%%.bc", UniqueFilename);
139  if (EC) {
140    errs() << getToolName()
141           << ": Error making unique filename: " << EC.message() << "\n";
142    return 1;
143  }
144  OutputFilename = UniqueFilename.str();
145
146  // set up the input file name
147  Expected<sys::fs::TempFile> Temp =
148      sys::fs::TempFile::create(OutputPrefix + "-input-%%%%%%%.bc");
149  if (!Temp) {
150    errs() << getToolName()
151           << ": Error making unique filename: " << toString(Temp.takeError())
152           << "\n";
153    return 1;
154  }
155  DiscardTemp Discard{*Temp};
156  raw_fd_ostream OS(Temp->FD, /*shouldClose*/ false);
157
158  WriteBitcodeToFile(Program, OS, PreserveBitcodeUseListOrder);
159  OS.flush();
160  if (OS.has_error()) {
161    errs() << "Error writing bitcode file: " << Temp->TmpName << "\n";
162    OS.clear_error();
163    return 1;
164  }
165
166  std::string tool = OptCmd;
167  if (OptCmd.empty()) {
168    if (ErrorOr<std::string> Path =
169            FindProgramByName("opt", getToolName(), &OutputPrefix))
170      tool = *Path;
171    else
172      errs() << Path.getError().message() << "\n";
173  }
174  if (tool.empty()) {
175    errs() << "Cannot find `opt' in PATH!\n";
176    return 1;
177  }
178  if (!sys::fs::exists(tool)) {
179    errs() << "Specified `opt' binary does not exist: " << tool << "\n";
180    return 1;
181  }
182
183  std::string Prog;
184  if (UseValgrind) {
185    if (ErrorOr<std::string> Path = sys::findProgramByName("valgrind"))
186      Prog = *Path;
187    else
188      errs() << Path.getError().message() << "\n";
189  } else
190    Prog = tool;
191  if (Prog.empty()) {
192    errs() << "Cannot find `valgrind' in PATH!\n";
193    return 1;
194  }
195
196  // setup the child process' arguments
197  SmallVector<StringRef, 8> Args;
198  if (UseValgrind) {
199    Args.push_back("valgrind");
200    Args.push_back("--error-exitcode=1");
201    Args.push_back("-q");
202    Args.push_back(tool);
203  } else
204    Args.push_back(tool);
205
206  for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
207    Args.push_back(OptArgs[i]);
208  Args.push_back("-disable-symbolication");
209  Args.push_back("-o");
210  Args.push_back(OutputFilename);
211  std::vector<std::string> pass_args;
212  for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
213    pass_args.push_back(std::string("-load"));
214    pass_args.push_back(PluginLoader::getPlugin(i));
215  }
216  for (std::vector<std::string>::const_iterator I = Passes.begin(),
217                                                E = Passes.end();
218       I != E; ++I)
219    pass_args.push_back(std::string("-") + (*I));
220  for (std::vector<std::string>::const_iterator I = pass_args.begin(),
221                                                E = pass_args.end();
222       I != E; ++I)
223    Args.push_back(I->c_str());
224  Args.push_back(Temp->TmpName.c_str());
225  Args.append(ExtraArgs.begin(), ExtraArgs.end());
226
227  LLVM_DEBUG(errs() << "\nAbout to run:\t";
228             for (unsigned i = 0, e = Args.size() - 1; i != e; ++i) errs()
229             << " " << Args[i];
230             errs() << "\n";);
231
232  Optional<StringRef> Redirects[3] = {None, None, None};
233  // Redirect stdout and stderr to nowhere if SilencePasses is given.
234  if (SilencePasses) {
235    Redirects[1] = "";
236    Redirects[2] = "";
237  }
238
239  std::string ErrMsg;
240  int result = sys::ExecuteAndWait(Prog, Args, None, Redirects, Timeout,
241                                   MemoryLimit, &ErrMsg);
242
243  // If we are supposed to delete the bitcode file or if the passes crashed,
244  // remove it now.  This may fail if the file was never created, but that's ok.
245  if (DeleteOutput || result != 0)
246    sys::fs::remove(OutputFilename);
247
248  if (!Quiet) {
249    if (result == 0)
250      outs() << "Success!\n";
251    else if (result > 0)
252      outs() << "Exited with error code '" << result << "'\n";
253    else if (result < 0) {
254      if (result == -1)
255        outs() << "Execute failed: " << ErrMsg << "\n";
256      else
257        outs() << "Crashed: " << ErrMsg << "\n";
258    }
259    if (result & 0x01000000)
260      outs() << "Dumped core\n";
261  }
262
263  // Was the child successful?
264  return result != 0;
265}
266
267std::unique_ptr<Module>
268BugDriver::runPassesOn(Module *M, const std::vector<std::string> &Passes,
269                       ArrayRef<std::string> ExtraArgs) {
270  std::string BitcodeResult;
271  if (runPasses(*M, Passes, BitcodeResult, false /*delete*/, true /*quiet*/,
272                ExtraArgs)) {
273    return nullptr;
274  }
275
276  std::unique_ptr<Module> Ret = parseInputFile(BitcodeResult, Context);
277  if (!Ret) {
278    errs() << getToolName() << ": Error reading bitcode file '" << BitcodeResult
279           << "'!\n";
280    exit(1);
281  }
282  sys::fs::remove(BitcodeResult);
283  return Ret;
284}
285