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 static cl::opt<bool> PreserveBitcodeUseListOrder(
46     "preserve-bc-uselistorder",
47     cl::desc("Preserve use-list order when writing LLVM bitcode."),
48     cl::init(true), cl::Hidden);
49 
50 namespace {
51   // ChildOutput - This option captures the name of the child output file that
52   // is set up by the parent bugpoint process
53   cl::opt<std::string> ChildOutput("child-output", cl::ReallyHidden);
54   cl::opt<std::string> OptCmd("opt-command", cl::init(""),
55                               cl::desc("Path to opt. (default: search path "
56                                        "for 'opt'.)"));
57 }
58 
59 /// writeProgramToFile - This writes the current "Program" to the named bitcode
60 /// file.  If an error occurs, true is returned.
61 ///
writeProgramToFileAux(tool_output_file & Out,const Module * M)62 static bool writeProgramToFileAux(tool_output_file &Out, const Module *M) {
63   WriteBitcodeToFile(M, Out.os(), PreserveBitcodeUseListOrder);
64   Out.os().close();
65   if (!Out.os().has_error()) {
66     Out.keep();
67     return false;
68   }
69   return true;
70 }
71 
writeProgramToFile(const std::string & Filename,int FD,const Module * M) const72 bool BugDriver::writeProgramToFile(const std::string &Filename, int FD,
73                                    const Module *M) const {
74   tool_output_file Out(Filename, FD);
75   return writeProgramToFileAux(Out, M);
76 }
77 
writeProgramToFile(const std::string & Filename,const Module * M) const78 bool BugDriver::writeProgramToFile(const std::string &Filename,
79                                    const Module *M) const {
80   std::error_code EC;
81   tool_output_file Out(Filename, EC, sys::fs::F_None);
82   if (!EC)
83     return writeProgramToFileAux(Out, M);
84   return true;
85 }
86 
87 
88 /// EmitProgressBitcode - This function is used to output the current Program
89 /// to a file named "bugpoint-ID.bc".
90 ///
EmitProgressBitcode(const Module * M,const std::string & ID,bool NoFlyer) const91 void BugDriver::EmitProgressBitcode(const Module *M,
92                                     const std::string &ID,
93                                     bool NoFlyer)  const {
94   // Output the input to the current pass to a bitcode file, emit a message
95   // telling the user how to reproduce it: opt -foo blah.bc
96   //
97   std::string Filename = OutputPrefix + "-" + ID + ".bc";
98   if (writeProgramToFile(Filename, M)) {
99     errs() <<  "Error opening file '" << Filename << "' for writing!\n";
100     return;
101   }
102 
103   outs() << "Emitted bitcode to '" << Filename << "'\n";
104   if (NoFlyer || PassesToRun.empty()) return;
105   outs() << "\n*** You can reproduce the problem with: ";
106   if (UseValgrind) 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 
114 cl::opt<bool> SilencePasses("silence-passes",
115         cl::desc("Suppress output of running passes (both stdout and stderr)"));
116 
117 static cl::list<std::string> OptArgs("opt-args", cl::Positional,
118                                      cl::desc("<opt arguments>..."),
119                                      cl::ZeroOrMore, cl::PositionalEatsArgs);
120 
121 /// runPasses - Run the specified passes on Program, outputting a bitcode file
122 /// and writing the filename into OutputFile if successful.  If the
123 /// optimizations fail for some reason (optimizer crashes), return true,
124 /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
125 /// deleted on success, and the filename string is undefined.  This prints to
126 /// outs() a single line message indicating whether compilation was successful
127 /// or failed.
128 ///
runPasses(Module * Program,const std::vector<std::string> & Passes,std::string & OutputFilename,bool DeleteOutput,bool Quiet,unsigned NumExtraArgs,const char * const * ExtraArgs) const129 bool BugDriver::runPasses(Module *Program,
130                           const std::vector<std::string> &Passes,
131                           std::string &OutputFilename, bool DeleteOutput,
132                           bool Quiet, unsigned NumExtraArgs,
133                           const char * const *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() << ": Error making unique filename: "
141            << EC.message() << "\n";
142     return 1;
143   }
144   OutputFilename = UniqueFilename.str();
145 
146   // set up the input file name
147   SmallString<128> InputFilename;
148   int InputFD;
149   EC = sys::fs::createUniqueFile(OutputPrefix + "-input-%%%%%%%.bc", InputFD,
150                                  InputFilename);
151   if (EC) {
152     errs() << getToolName() << ": Error making unique filename: "
153            << EC.message() << "\n";
154     return 1;
155   }
156 
157   tool_output_file InFile(InputFilename, InputFD);
158 
159   WriteBitcodeToFile(Program, InFile.os(), PreserveBitcodeUseListOrder);
160   InFile.os().close();
161   if (InFile.os().has_error()) {
162     errs() << "Error writing bitcode file: " << InputFilename << "\n";
163     InFile.os().clear_error();
164     return 1;
165   }
166 
167   std::string tool = OptCmd;
168   if (OptCmd.empty()) {
169     if (ErrorOr<std::string> Path = sys::findProgramByName("opt"))
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 
179   std::string Prog;
180   if (UseValgrind) {
181     if (ErrorOr<std::string> Path = sys::findProgramByName("valgrind"))
182       Prog = *Path;
183     else
184       errs() << Path.getError().message() << "\n";
185   } else
186     Prog = tool;
187   if (Prog.empty()) {
188     errs() << "Cannot find `valgrind' in PATH!\n";
189     return 1;
190   }
191 
192   // Ok, everything that could go wrong before running opt is done.
193   InFile.keep();
194 
195   // setup the child process' arguments
196   SmallVector<const char*, 8> Args;
197   if (UseValgrind) {
198     Args.push_back("valgrind");
199     Args.push_back("--error-exitcode=1");
200     Args.push_back("-q");
201     Args.push_back(tool.c_str());
202   } else
203     Args.push_back(tool.c_str());
204 
205   Args.push_back("-o");
206   Args.push_back(OutputFilename.c_str());
207   for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
208     Args.push_back(OptArgs[i].c_str());
209   std::vector<std::string> pass_args;
210   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
211     pass_args.push_back( std::string("-load"));
212     pass_args.push_back( PluginLoader::getPlugin(i));
213   }
214   for (std::vector<std::string>::const_iterator I = Passes.begin(),
215        E = Passes.end(); I != E; ++I )
216     pass_args.push_back( std::string("-") + (*I) );
217   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
218        E = pass_args.end(); I != E; ++I )
219     Args.push_back(I->c_str());
220   Args.push_back(InputFilename.c_str());
221   for (unsigned i = 0; i < NumExtraArgs; ++i)
222     Args.push_back(*ExtraArgs);
223   Args.push_back(nullptr);
224 
225   DEBUG(errs() << "\nAbout to run:\t";
226         for (unsigned i = 0, e = Args.size()-1; i != e; ++i)
227           errs() << " " << Args[i];
228         errs() << "\n";
229         );
230 
231   // Redirect stdout and stderr to nowhere if SilencePasses is given
232   StringRef Nowhere;
233   const StringRef *Redirects[3] = {nullptr, &Nowhere, &Nowhere};
234 
235   std::string ErrMsg;
236   int result = sys::ExecuteAndWait(Prog, Args.data(), nullptr,
237                                    (SilencePasses ? Redirects : nullptr),
238                                    Timeout, MemoryLimit, &ErrMsg);
239 
240   // If we are supposed to delete the bitcode file or if the passes crashed,
241   // remove it now.  This may fail if the file was never created, but that's ok.
242   if (DeleteOutput || result != 0)
243     sys::fs::remove(OutputFilename);
244 
245   // Remove the temporary input file as well
246   sys::fs::remove(InputFilename.c_str());
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 
267 
268 std::unique_ptr<Module>
runPassesOn(Module * M,const std::vector<std::string> & Passes,bool AutoDebugCrashes,unsigned NumExtraArgs,const char * const * ExtraArgs)269 BugDriver::runPassesOn(Module *M, const std::vector<std::string> &Passes,
270                        bool AutoDebugCrashes, unsigned NumExtraArgs,
271                        const char *const *ExtraArgs) {
272   std::string BitcodeResult;
273   if (runPasses(M, Passes, BitcodeResult, false/*delete*/, true/*quiet*/,
274                 NumExtraArgs, ExtraArgs)) {
275     if (AutoDebugCrashes) {
276       errs() << " Error running this sequence of passes"
277              << " on the input program!\n";
278       delete swapProgramIn(M);
279       EmitProgressBitcode(M, "pass-error",  false);
280       exit(debugOptimizerCrash());
281     }
282     return nullptr;
283   }
284 
285   std::unique_ptr<Module> Ret = parseInputFile(BitcodeResult, Context);
286   if (!Ret) {
287     errs() << getToolName() << ": Error reading bitcode file '"
288            << BitcodeResult << "'!\n";
289     exit(1);
290   }
291   sys::fs::remove(BitcodeResult);
292   return Ret;
293 }
294