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/Analysis/Verifier.h"
20 #include "llvm/Bitcode/ReaderWriter.h"
21 #include "llvm/IR/DataLayout.h"
22 #include "llvm/IR/Module.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/PathV1.h"
29 #include "llvm/Support/Program.h"
30 #include "llvm/Support/SystemUtils.h"
31 #include "llvm/Support/ToolOutputFile.h"
32 
33 #define DONT_GET_PLUGIN_LOADER_OPTION
34 #include "llvm/Support/PluginLoader.h"
35 
36 #include <fstream>
37 using namespace llvm;
38 
39 namespace llvm {
40   extern cl::opt<std::string> OutputPrefix;
41 }
42 
43 namespace {
44   // ChildOutput - This option captures the name of the child output file that
45   // is set up by the parent bugpoint process
46   cl::opt<std::string> ChildOutput("child-output", cl::ReallyHidden);
47 }
48 
49 /// writeProgramToFile - This writes the current "Program" to the named bitcode
50 /// file.  If an error occurs, true is returned.
51 ///
52 bool BugDriver::writeProgramToFile(const std::string &Filename,
53                                    const Module *M) const {
54   std::string ErrInfo;
55   tool_output_file Out(Filename.c_str(), ErrInfo,
56                        raw_fd_ostream::F_Binary);
57   if (ErrInfo.empty()) {
58     WriteBitcodeToFile(M, Out.os());
59     Out.os().close();
60     if (!Out.os().has_error()) {
61       Out.keep();
62       return false;
63     }
64   }
65   Out.os().clear_error();
66   return true;
67 }
68 
69 
70 /// EmitProgressBitcode - This function is used to output the current Program
71 /// to a file named "bugpoint-ID.bc".
72 ///
73 void BugDriver::EmitProgressBitcode(const Module *M,
74                                     const std::string &ID,
75                                     bool NoFlyer)  const {
76   // Output the input to the current pass to a bitcode file, emit a message
77   // telling the user how to reproduce it: opt -foo blah.bc
78   //
79   std::string Filename = OutputPrefix + "-" + ID + ".bc";
80   if (writeProgramToFile(Filename, M)) {
81     errs() <<  "Error opening file '" << Filename << "' for writing!\n";
82     return;
83   }
84 
85   outs() << "Emitted bitcode to '" << Filename << "'\n";
86   if (NoFlyer || PassesToRun.empty()) return;
87   outs() << "\n*** You can reproduce the problem with: ";
88   if (UseValgrind) outs() << "valgrind ";
89   outs() << "opt " << Filename;
90   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
91     outs() << " -load " << PluginLoader::getPlugin(i);
92   }
93   outs() << " " << getPassesString(PassesToRun) << "\n";
94 }
95 
96 cl::opt<bool> SilencePasses("silence-passes",
97         cl::desc("Suppress output of running passes (both stdout and stderr)"));
98 
99 static cl::list<std::string> OptArgs("opt-args", cl::Positional,
100                                      cl::desc("<opt arguments>..."),
101                                      cl::ZeroOrMore, cl::PositionalEatsArgs);
102 
103 /// runPasses - Run the specified passes on Program, outputting a bitcode file
104 /// and writing the filename into OutputFile if successful.  If the
105 /// optimizations fail for some reason (optimizer crashes), return true,
106 /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
107 /// deleted on success, and the filename string is undefined.  This prints to
108 /// outs() a single line message indicating whether compilation was successful
109 /// or failed.
110 ///
111 bool BugDriver::runPasses(Module *Program,
112                           const std::vector<std::string> &Passes,
113                           std::string &OutputFilename, bool DeleteOutput,
114                           bool Quiet, unsigned NumExtraArgs,
115                           const char * const *ExtraArgs) const {
116   // setup the output file name
117   outs().flush();
118   sys::Path uniqueFilename(OutputPrefix + "-output.bc");
119   std::string ErrMsg;
120   if (uniqueFilename.makeUnique(true, &ErrMsg)) {
121     errs() << getToolName() << ": Error making unique filename: "
122            << ErrMsg << "\n";
123     return(1);
124   }
125   OutputFilename = uniqueFilename.str();
126 
127   // set up the input file name
128   sys::Path inputFilename(OutputPrefix + "-input.bc");
129   if (inputFilename.makeUnique(true, &ErrMsg)) {
130     errs() << getToolName() << ": Error making unique filename: "
131            << ErrMsg << "\n";
132     return(1);
133   }
134 
135   std::string ErrInfo;
136   tool_output_file InFile(inputFilename.c_str(), ErrInfo,
137                           raw_fd_ostream::F_Binary);
138 
139 
140   if (!ErrInfo.empty()) {
141     errs() << "Error opening bitcode file: " << inputFilename.str() << "\n";
142     return 1;
143   }
144   WriteBitcodeToFile(Program, InFile.os());
145   InFile.os().close();
146   if (InFile.os().has_error()) {
147     errs() << "Error writing bitcode file: " << inputFilename.str() << "\n";
148     InFile.os().clear_error();
149     return 1;
150   }
151 
152   std::string tool = sys::FindProgramByName("opt");
153   if (tool.empty()) {
154     errs() << "Cannot find `opt' in PATH!\n";
155     return 1;
156   }
157 
158   // Ok, everything that could go wrong before running opt is done.
159   InFile.keep();
160 
161   // setup the child process' arguments
162   SmallVector<const char*, 8> Args;
163   if (UseValgrind) {
164     Args.push_back("valgrind");
165     Args.push_back("--error-exitcode=1");
166     Args.push_back("-q");
167     Args.push_back(tool.c_str());
168   } else
169     Args.push_back(tool.c_str());
170 
171   Args.push_back("-o");
172   Args.push_back(OutputFilename.c_str());
173   for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
174     Args.push_back(OptArgs[i].c_str());
175   std::vector<std::string> pass_args;
176   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
177     pass_args.push_back( std::string("-load"));
178     pass_args.push_back( PluginLoader::getPlugin(i));
179   }
180   for (std::vector<std::string>::const_iterator I = Passes.begin(),
181        E = Passes.end(); I != E; ++I )
182     pass_args.push_back( std::string("-") + (*I) );
183   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
184        E = pass_args.end(); I != E; ++I )
185     Args.push_back(I->c_str());
186   Args.push_back(inputFilename.c_str());
187   for (unsigned i = 0; i < NumExtraArgs; ++i)
188     Args.push_back(*ExtraArgs);
189   Args.push_back(0);
190 
191   DEBUG(errs() << "\nAbout to run:\t";
192         for (unsigned i = 0, e = Args.size()-1; i != e; ++i)
193           errs() << " " << Args[i];
194         errs() << "\n";
195         );
196 
197   sys::Path prog;
198   if (UseValgrind)
199     prog = sys::FindProgramByName("valgrind");
200   else
201     prog = tool;
202 
203   // Redirect stdout and stderr to nowhere if SilencePasses is given
204   StringRef Nowhere;
205   const StringRef *Redirects[3] = {0, &Nowhere, &Nowhere};
206 
207   int result = sys::ExecuteAndWait(prog.str(), Args.data(), 0,
208                                    (SilencePasses ? Redirects : 0), Timeout,
209                                    MemoryLimit, &ErrMsg);
210 
211   // If we are supposed to delete the bitcode file or if the passes crashed,
212   // remove it now.  This may fail if the file was never created, but that's ok.
213   if (DeleteOutput || result != 0)
214     sys::Path(OutputFilename).eraseFromDisk();
215 
216   // Remove the temporary input file as well
217   inputFilename.eraseFromDisk();
218 
219   if (!Quiet) {
220     if (result == 0)
221       outs() << "Success!\n";
222     else if (result > 0)
223       outs() << "Exited with error code '" << result << "'\n";
224     else if (result < 0) {
225       if (result == -1)
226         outs() << "Execute failed: " << ErrMsg << "\n";
227       else
228         outs() << "Crashed: " << ErrMsg << "\n";
229     }
230     if (result & 0x01000000)
231       outs() << "Dumped core\n";
232   }
233 
234   // Was the child successful?
235   return result != 0;
236 }
237 
238 
239 /// runPassesOn - Carefully run the specified set of pass on the specified
240 /// module, returning the transformed module on success, or a null pointer on
241 /// failure.
242 Module *BugDriver::runPassesOn(Module *M,
243                                const std::vector<std::string> &Passes,
244                                bool AutoDebugCrashes, unsigned NumExtraArgs,
245                                const char * const *ExtraArgs) {
246   std::string BitcodeResult;
247   if (runPasses(M, Passes, BitcodeResult, false/*delete*/, true/*quiet*/,
248                 NumExtraArgs, ExtraArgs)) {
249     if (AutoDebugCrashes) {
250       errs() << " Error running this sequence of passes"
251              << " on the input program!\n";
252       delete swapProgramIn(M);
253       EmitProgressBitcode(M, "pass-error",  false);
254       exit(debugOptimizerCrash());
255     }
256     return 0;
257   }
258 
259   Module *Ret = ParseInputFile(BitcodeResult, Context);
260   if (Ret == 0) {
261     errs() << getToolName() << ": Error reading bitcode file '"
262            << BitcodeResult << "'!\n";
263     exit(1);
264   }
265   sys::Path(BitcodeResult).eraseFromDisk();  // No longer need the file on disk
266   return Ret;
267 }
268