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/Module.h"
20 #include "llvm/PassManager.h"
21 #include "llvm/Analysis/Verifier.h"
22 #include "llvm/Bitcode/ReaderWriter.h"
23 #include "llvm/Target/TargetData.h"
24 #include "llvm/Support/FileUtilities.h"
25 #include "llvm/Support/CommandLine.h"
26 #include "llvm/Support/SystemUtils.h"
27 #include "llvm/Support/Debug.h"
28 #include "llvm/Support/ToolOutputFile.h"
29 #include "llvm/Support/Path.h"
30 #include "llvm/Support/Program.h"
31 
32 #define DONT_GET_PLUGIN_LOADER_OPTION
33 #include "llvm/Support/PluginLoader.h"
34 
35 #include <fstream>
36 using namespace llvm;
37 
38 namespace llvm {
39   extern cl::opt<std::string> OutputPrefix;
40 }
41 
42 namespace {
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 }
47 
48 /// writeProgramToFile - This writes the current "Program" to the named bitcode
49 /// file.  If an error occurs, true is returned.
50 ///
51 bool BugDriver::writeProgramToFile(const std::string &Filename,
52                                    const Module *M) const {
53   std::string ErrInfo;
54   tool_output_file Out(Filename.c_str(), ErrInfo,
55                        raw_fd_ostream::F_Binary);
56   if (ErrInfo.empty()) {
57     WriteBitcodeToFile(M, Out.os());
58     Out.os().close();
59     if (!Out.os().has_error()) {
60       Out.keep();
61       return false;
62     }
63   }
64   Out.os().clear_error();
65   return true;
66 }
67 
68 
69 /// EmitProgressBitcode - This function is used to output the current Program
70 /// to a file named "bugpoint-ID.bc".
71 ///
72 void BugDriver::EmitProgressBitcode(const Module *M,
73                                     const std::string &ID,
74                                     bool NoFlyer)  const {
75   // Output the input to the current pass to a bitcode file, emit a message
76   // telling the user how to reproduce it: opt -foo blah.bc
77   //
78   std::string Filename = OutputPrefix + "-" + ID + ".bc";
79   if (writeProgramToFile(Filename, M)) {
80     errs() <<  "Error opening file '" << Filename << "' for writing!\n";
81     return;
82   }
83 
84   outs() << "Emitted bitcode to '" << Filename << "'\n";
85   if (NoFlyer || PassesToRun.empty()) return;
86   outs() << "\n*** You can reproduce the problem with: ";
87   if (UseValgrind) outs() << "valgrind ";
88   outs() << "opt " << Filename << " ";
89   outs() << getPassesString(PassesToRun) << "\n";
90 }
91 
92 cl::opt<bool> SilencePasses("silence-passes", cl::desc("Suppress output of running passes (both stdout and stderr)"));
93 
94 static cl::list<std::string> OptArgs("opt-args", cl::Positional,
95                                      cl::desc("<opt arguments>..."),
96                                      cl::ZeroOrMore, cl::PositionalEatsArgs);
97 
98 /// runPasses - Run the specified passes on Program, outputting a bitcode file
99 /// and writing the filename into OutputFile if successful.  If the
100 /// optimizations fail for some reason (optimizer crashes), return true,
101 /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
102 /// deleted on success, and the filename string is undefined.  This prints to
103 /// outs() a single line message indicating whether compilation was successful
104 /// or failed.
105 ///
106 bool BugDriver::runPasses(Module *Program,
107                           const std::vector<std::string> &Passes,
108                           std::string &OutputFilename, bool DeleteOutput,
109                           bool Quiet, unsigned NumExtraArgs,
110                           const char * const *ExtraArgs) const {
111   // setup the output file name
112   outs().flush();
113   sys::Path uniqueFilename(OutputPrefix + "-output.bc");
114   std::string ErrMsg;
115   if (uniqueFilename.makeUnique(true, &ErrMsg)) {
116     errs() << getToolName() << ": Error making unique filename: "
117            << ErrMsg << "\n";
118     return(1);
119   }
120   OutputFilename = uniqueFilename.str();
121 
122   // set up the input file name
123   sys::Path inputFilename(OutputPrefix + "-input.bc");
124   if (inputFilename.makeUnique(true, &ErrMsg)) {
125     errs() << getToolName() << ": Error making unique filename: "
126            << ErrMsg << "\n";
127     return(1);
128   }
129 
130   std::string ErrInfo;
131   tool_output_file InFile(inputFilename.c_str(), ErrInfo,
132                           raw_fd_ostream::F_Binary);
133 
134 
135   if (!ErrInfo.empty()) {
136     errs() << "Error opening bitcode file: " << inputFilename.str() << "\n";
137     return 1;
138   }
139   WriteBitcodeToFile(Program, InFile.os());
140   InFile.os().close();
141   if (InFile.os().has_error()) {
142     errs() << "Error writing bitcode file: " << inputFilename.str() << "\n";
143     InFile.os().clear_error();
144     return 1;
145   }
146 
147   sys::Path tool = PrependMainExecutablePath("opt", getToolName(),
148                                              (void*)"opt");
149   if (tool.empty()) {
150     errs() << "Cannot find `opt' in executable directory!\n";
151     return 1;
152   }
153 
154   // Ok, everything that could go wrong before running opt is done.
155   InFile.keep();
156 
157   // setup the child process' arguments
158   SmallVector<const char*, 8> Args;
159   std::string Opt = tool.str();
160   if (UseValgrind) {
161     Args.push_back("valgrind");
162     Args.push_back("--error-exitcode=1");
163     Args.push_back("-q");
164     Args.push_back(tool.c_str());
165   } else
166     Args.push_back(Opt.c_str());
167 
168   Args.push_back("-o");
169   Args.push_back(OutputFilename.c_str());
170   for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
171     Args.push_back(OptArgs[i].c_str());
172   std::vector<std::string> pass_args;
173   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
174     pass_args.push_back( std::string("-load"));
175     pass_args.push_back( PluginLoader::getPlugin(i));
176   }
177   for (std::vector<std::string>::const_iterator I = Passes.begin(),
178        E = Passes.end(); I != E; ++I )
179     pass_args.push_back( std::string("-") + (*I) );
180   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
181        E = pass_args.end(); I != E; ++I )
182     Args.push_back(I->c_str());
183   Args.push_back(inputFilename.c_str());
184   for (unsigned i = 0; i < NumExtraArgs; ++i)
185     Args.push_back(*ExtraArgs);
186   Args.push_back(0);
187 
188   DEBUG(errs() << "\nAbout to run:\t";
189         for (unsigned i = 0, e = Args.size()-1; i != e; ++i)
190           errs() << " " << Args[i];
191         errs() << "\n";
192         );
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.data(), 0,
205                                             (SilencePasses ? Redirects : 0),
206                                             Timeout, MemoryLimit, &ErrMsg);
207 
208   // If we are supposed to delete the bitcode file or if the passes crashed,
209   // remove it now.  This may fail if the file was never created, but that's ok.
210   if (DeleteOutput || result != 0)
211     sys::Path(OutputFilename).eraseFromDisk();
212 
213   // Remove the temporary input file as well
214   inputFilename.eraseFromDisk();
215 
216   if (!Quiet) {
217     if (result == 0)
218       outs() << "Success!\n";
219     else if (result > 0)
220       outs() << "Exited with error code '" << result << "'\n";
221     else if (result < 0) {
222       if (result == -1)
223         outs() << "Execute failed: " << ErrMsg << "\n";
224       else
225         outs() << "Crashed with signal #" << abs(result) << "\n";
226     }
227     if (result & 0x01000000)
228       outs() << "Dumped core\n";
229   }
230 
231   // Was the child successful?
232   return result != 0;
233 }
234 
235 
236 /// runPassesOn - Carefully run the specified set of pass on the specified
237 /// module, returning the transformed module on success, or a null pointer on
238 /// failure.
239 Module *BugDriver::runPassesOn(Module *M,
240                                const std::vector<std::string> &Passes,
241                                bool AutoDebugCrashes, unsigned NumExtraArgs,
242                                const char * const *ExtraArgs) {
243   std::string BitcodeResult;
244   if (runPasses(M, 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 swapProgramIn(M);
250       EmitProgressBitcode(M, "pass-error",  false);
251       exit(debugOptimizerCrash());
252     }
253     return 0;
254   }
255 
256   Module *Ret = ParseInputFile(BitcodeResult, Context);
257   if (Ret == 0) {
258     errs() << getToolName() << ": Error reading bitcode file '"
259            << BitcodeResult << "'!\n";
260     exit(1);
261   }
262   sys::Path(BitcodeResult).eraseFromDisk();  // No longer need the file on disk
263   return Ret;
264 }
265