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 // Note: as a short term hack, the old Unix-specific code and platform-
19 // independent code co-exist via conditional compilation until it is verified
20 // that the new code works correctly on Unix.
21 
22 #include "BugDriver.h"
23 #include "llvm/Module.h"
24 #include "llvm/PassManager.h"
25 #include "llvm/Analysis/Verifier.h"
26 #include "llvm/Bitcode/ReaderWriter.h"
27 #include "llvm/Target/TargetData.h"
28 #include "llvm/Support/FileUtilities.h"
29 #include "llvm/Support/CommandLine.h"
30 #include "llvm/Support/Streams.h"
31 #include "llvm/System/Path.h"
32 #include "llvm/System/Program.h"
33 #include "llvm/Config/alloca.h"
34 
35 #define DONT_GET_PLUGIN_LOADER_OPTION
36 #include "llvm/Support/PluginLoader.h"
37 
38 #include <fstream>
39 using namespace llvm;
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   cl::opt<bool> UseValgrind("enable-valgrind",
47                             cl::desc("Run optimizations through valgrind"));
48 }
49 
50 /// writeProgramToFile - This writes the current "Program" to the named bitcode
51 /// file.  If an error occurs, true is returned.
52 ///
53 bool BugDriver::writeProgramToFile(const std::string &Filename,
54                                    Module *M) const {
55   std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
56                                std::ios::binary;
57   std::ofstream Out(Filename.c_str(), io_mode);
58   if (!Out.good()) return true;
59 
60   WriteBitcodeToFile(M ? M : Program, Out);
61   return false;
62 }
63 
64 
65 /// EmitProgressBitcode - This function is used to output the current Program
66 /// to a file named "bugpoint-ID.bc".
67 ///
68 void BugDriver::EmitProgressBitcode(const std::string &ID, bool NoFlyer) {
69   // Output the input to the current pass to a bitcode file, emit a message
70   // telling the user how to reproduce it: opt -foo blah.bc
71   //
72   std::string Filename = "bugpoint-" + ID + ".bc";
73   if (writeProgramToFile(Filename)) {
74     cerr <<  "Error opening file '" << Filename << "' for writing!\n";
75     return;
76   }
77 
78   cout << "Emitted bitcode to '" << Filename << "'\n";
79   if (NoFlyer || PassesToRun.empty()) return;
80   cout << "\n*** You can reproduce the problem with: ";
81   cout << "opt " << Filename << " ";
82   cout << getPassesString(PassesToRun) << "\n";
83 }
84 
85 int BugDriver::runPassesAsChild(const std::vector<const PassInfo*> &Passes) {
86 
87   std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
88                                std::ios::binary;
89   std::ofstream OutFile(ChildOutput.c_str(), io_mode);
90   if (!OutFile.good()) {
91     cerr << "Error opening bitcode file: " << ChildOutput << "\n";
92     return 1;
93   }
94 
95   PassManager PM;
96   // Make sure that the appropriate target data is always used...
97   PM.add(new TargetData(Program));
98 
99   for (unsigned i = 0, e = Passes.size(); i != e; ++i) {
100     if (Passes[i]->getNormalCtor())
101       PM.add(Passes[i]->getNormalCtor()());
102     else
103       cerr << "Cannot create pass yet: " << Passes[i]->getPassName() << "\n";
104   }
105   // Check that the module is well formed on completion of optimization
106   PM.add(createVerifierPass());
107 
108   // Write bitcode out to disk as the last step...
109   PM.add(CreateBitcodeWriterPass(OutFile));
110 
111   // Run all queued passes.
112   PM.run(*Program);
113 
114   return 0;
115 }
116 
117 cl::opt<bool> SilencePasses("silence-passes", cl::desc("Suppress output of running passes (both stdout and stderr)"));
118 
119 /// runPasses - Run the specified passes on Program, outputting a bitcode file
120 /// and writing the filename into OutputFile if successful.  If the
121 /// optimizations fail for some reason (optimizer crashes), return true,
122 /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
123 /// deleted on success, and the filename string is undefined.  This prints to
124 /// cout a single line message indicating whether compilation was successful or
125 /// failed.
126 ///
127 bool BugDriver::runPasses(const std::vector<const PassInfo*> &Passes,
128                           std::string &OutputFilename, bool DeleteOutput,
129                           bool Quiet, unsigned NumExtraArgs,
130                           const char * const *ExtraArgs) const {
131   // setup the output file name
132   cout << std::flush;
133   sys::Path uniqueFilename("bugpoint-output.bc");
134   std::string ErrMsg;
135   if (uniqueFilename.makeUnique(true, &ErrMsg)) {
136     cerr << getToolName() << ": Error making unique filename: "
137          << ErrMsg << "\n";
138     return(1);
139   }
140   OutputFilename = uniqueFilename.toString();
141 
142   // set up the input file name
143   sys::Path inputFilename("bugpoint-input.bc");
144   if (inputFilename.makeUnique(true, &ErrMsg)) {
145     cerr << getToolName() << ": Error making unique filename: "
146          << ErrMsg << "\n";
147     return(1);
148   }
149   std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
150                                std::ios::binary;
151   std::ofstream InFile(inputFilename.c_str(), io_mode);
152   if (!InFile.good()) {
153     cerr << "Error opening bitcode file: " << inputFilename << "\n";
154     return(1);
155   }
156   WriteBitcodeToFile(Program, InFile);
157   InFile.close();
158 
159   // setup the child process' arguments
160   const char** args = (const char**)
161     alloca(sizeof(const char*) *
162            (Passes.size()+13+2*PluginLoader::getNumPlugins()+NumExtraArgs));
163   int n = 0;
164   sys::Path tool = sys::Program::FindProgramByName(ToolName);
165   if (UseValgrind) {
166     args[n++] = "valgrind";
167     args[n++] = "--error-exitcode=1";
168     args[n++] = "-q";
169     args[n++] = tool.c_str();
170   } else
171     args[n++] = ToolName.c_str();
172 
173   args[n++] = "-as-child";
174   args[n++] = "-child-output";
175   args[n++] = OutputFilename.c_str();
176   std::vector<std::string> pass_args;
177   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
178     pass_args.push_back( std::string("-load"));
179     pass_args.push_back( PluginLoader::getPlugin(i));
180   }
181   for (std::vector<const PassInfo*>::const_iterator I = Passes.begin(),
182        E = Passes.end(); I != E; ++I )
183     pass_args.push_back( std::string("-") + (*I)->getPassArgument() );
184   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
185        E = pass_args.end(); I != E; ++I )
186     args[n++] = I->c_str();
187   args[n++] = inputFilename.c_str();
188   for (unsigned i = 0; i < NumExtraArgs; ++i)
189     args[n++] = *ExtraArgs;
190   args[n++] = 0;
191 
192   sys::Path prog;
193   if (UseValgrind)
194     prog = sys::Program::FindProgramByName("valgrind");
195   else
196     prog = tool;
197 
198   // Redirect stdout and stderr to nowhere if SilencePasses is given
199   sys::Path Nowhere;
200   const sys::Path *Redirects[3] = {0, &Nowhere, &Nowhere};
201 
202   int result = sys::Program::ExecuteAndWait(prog, args, 0, (SilencePasses ? Redirects : 0),
203                                             Timeout, MemoryLimit, &ErrMsg);
204 
205   // If we are supposed to delete the bitcode file or if the passes crashed,
206   // remove it now.  This may fail if the file was never created, but that's ok.
207   if (DeleteOutput || result != 0)
208     sys::Path(OutputFilename).eraseFromDisk();
209 
210   // Remove the temporary input file as well
211   inputFilename.eraseFromDisk();
212 
213   if (!Quiet) {
214     if (result == 0)
215       cout << "Success!\n";
216     else if (result > 0)
217       cout << "Exited with error code '" << result << "'\n";
218     else if (result < 0) {
219       if (result == -1)
220         cout << "Execute failed: " << ErrMsg << "\n";
221       else
222         cout << "Crashed with signal #" << abs(result) << "\n";
223     }
224     if (result & 0x01000000)
225       cout << "Dumped core\n";
226   }
227 
228   // Was the child successful?
229   return result != 0;
230 }
231 
232 
233 /// runPassesOn - Carefully run the specified set of pass on the specified
234 /// module, returning the transformed module on success, or a null pointer on
235 /// failure.
236 Module *BugDriver::runPassesOn(Module *M,
237                                const std::vector<const PassInfo*> &Passes,
238                                bool AutoDebugCrashes, unsigned NumExtraArgs,
239                                const char * const *ExtraArgs) {
240   Module *OldProgram = swapProgramIn(M);
241   std::string BitcodeResult;
242   if (runPasses(Passes, BitcodeResult, false/*delete*/, true/*quiet*/,
243                 NumExtraArgs, ExtraArgs)) {
244     if (AutoDebugCrashes) {
245       cerr << " Error running this sequence of passes"
246            << " on the input program!\n";
247       delete OldProgram;
248       EmitProgressBitcode("pass-error",  false);
249       exit(debugOptimizerCrash());
250     }
251     swapProgramIn(OldProgram);
252     return 0;
253   }
254 
255   // Restore the current program.
256   swapProgramIn(OldProgram);
257 
258   Module *Ret = ParseInputFile(BitcodeResult, Context);
259   if (Ret == 0) {
260     cerr << getToolName() << ": Error reading bitcode file '"
261          << BitcodeResult << "'!\n";
262     exit(1);
263   }
264   sys::Path(BitcodeResult).eraseFromDisk();  // No longer need the file on disk
265   return Ret;
266 }
267