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/LegacyPassManager.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/IR/Verifier.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 
37 using namespace llvm;
38 
39 #define DEBUG_TYPE "bugpoint"
40 
41 namespace llvm {
42   extern cl::opt<std::string> OutputPrefix;
43 }
44 
45 namespace {
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 ///
57 static 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 
67 bool BugDriver::writeProgramToFile(const std::string &Filename, int FD,
68                                    const Module *M) const {
69   tool_output_file Out(Filename, FD);
70   return writeProgramToFileAux(Out, M);
71 }
72 
73 bool BugDriver::writeProgramToFile(const std::string &Filename,
74                                    const Module *M) const {
75   std::error_code EC;
76   tool_output_file Out(Filename, EC, sys::fs::F_None);
77   if (!EC)
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 ///
86 void 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 
109 cl::opt<bool> SilencePasses("silence-passes",
110         cl::desc("Suppress output of running passes (both stdout and stderr)"));
111 
112 static 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 ///
124 bool 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, 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;
163   if (OptCmd.empty()) {
164     if (ErrorOr<std::string> Path = sys::findProgramByName("opt"))
165       tool = *Path;
166     else
167       errs() << Path.getError().message() << "\n";
168   }
169   if (tool.empty()) {
170     errs() << "Cannot find `opt' in PATH!\n";
171     return 1;
172   }
173 
174   std::string Prog;
175   if (UseValgrind) {
176     if (ErrorOr<std::string> Path = sys::findProgramByName("valgrind"))
177       Prog = *Path;
178     else
179       errs() << Path.getError().message() << "\n";
180   } else
181     Prog = tool;
182   if (Prog.empty()) {
183     errs() << "Cannot find `valgrind' in PATH!\n";
184     return 1;
185   }
186 
187   // Ok, everything that could go wrong before running opt is done.
188   InFile.keep();
189 
190   // setup the child process' arguments
191   SmallVector<const char*, 8> Args;
192   if (UseValgrind) {
193     Args.push_back("valgrind");
194     Args.push_back("--error-exitcode=1");
195     Args.push_back("-q");
196     Args.push_back(tool.c_str());
197   } else
198     Args.push_back(tool.c_str());
199 
200   Args.push_back("-o");
201   Args.push_back(OutputFilename.c_str());
202   for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
203     Args.push_back(OptArgs[i].c_str());
204   std::vector<std::string> pass_args;
205   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
206     pass_args.push_back( std::string("-load"));
207     pass_args.push_back( PluginLoader::getPlugin(i));
208   }
209   for (std::vector<std::string>::const_iterator I = Passes.begin(),
210        E = Passes.end(); I != E; ++I )
211     pass_args.push_back( std::string("-") + (*I) );
212   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
213        E = pass_args.end(); I != E; ++I )
214     Args.push_back(I->c_str());
215   Args.push_back(InputFilename.c_str());
216   for (unsigned i = 0; i < NumExtraArgs; ++i)
217     Args.push_back(*ExtraArgs);
218   Args.push_back(nullptr);
219 
220   DEBUG(errs() << "\nAbout to run:\t";
221         for (unsigned i = 0, e = Args.size()-1; i != e; ++i)
222           errs() << " " << Args[i];
223         errs() << "\n";
224         );
225 
226   // Redirect stdout and stderr to nowhere if SilencePasses is given
227   StringRef Nowhere;
228   const StringRef *Redirects[3] = {nullptr, &Nowhere, &Nowhere};
229 
230   std::string ErrMsg;
231   int result = sys::ExecuteAndWait(Prog, Args.data(), nullptr,
232                                    (SilencePasses ? Redirects : nullptr),
233                                    Timeout, MemoryLimit, &ErrMsg);
234 
235   // If we are supposed to delete the bitcode file or if the passes crashed,
236   // remove it now.  This may fail if the file was never created, but that's ok.
237   if (DeleteOutput || result != 0)
238     sys::fs::remove(OutputFilename);
239 
240   // Remove the temporary input file as well
241   sys::fs::remove(InputFilename.c_str());
242 
243   if (!Quiet) {
244     if (result == 0)
245       outs() << "Success!\n";
246     else if (result > 0)
247       outs() << "Exited with error code '" << result << "'\n";
248     else if (result < 0) {
249       if (result == -1)
250         outs() << "Execute failed: " << ErrMsg << "\n";
251       else
252         outs() << "Crashed: " << ErrMsg << "\n";
253     }
254     if (result & 0x01000000)
255       outs() << "Dumped core\n";
256   }
257 
258   // Was the child successful?
259   return result != 0;
260 }
261 
262 
263 std::unique_ptr<Module>
264 BugDriver::runPassesOn(Module *M, const std::vector<std::string> &Passes,
265                        bool AutoDebugCrashes, unsigned NumExtraArgs,
266                        const char *const *ExtraArgs) {
267   std::string BitcodeResult;
268   if (runPasses(M, Passes, BitcodeResult, false/*delete*/, true/*quiet*/,
269                 NumExtraArgs, ExtraArgs)) {
270     if (AutoDebugCrashes) {
271       errs() << " Error running this sequence of passes"
272              << " on the input program!\n";
273       delete swapProgramIn(M);
274       EmitProgressBitcode(M, "pass-error",  false);
275       exit(debugOptimizerCrash());
276     }
277     return nullptr;
278   }
279 
280   std::unique_ptr<Module> Ret = parseInputFile(BitcodeResult, Context);
281   if (!Ret) {
282     errs() << getToolName() << ": Error reading bitcode file '"
283            << BitcodeResult << "'!\n";
284     exit(1);
285   }
286   sys::fs::remove(BitcodeResult);
287   return Ret;
288 }
289