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/BitcodeWriter.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 // ChildOutput - This option captures the name of the child output file that
51 // is set up by the parent bugpoint process
52 static cl::opt<std::string> ChildOutput("child-output", cl::ReallyHidden);
53 static cl::opt<std::string>
54     OptCmd("opt-command", cl::init(""),
55            cl::desc("Path to opt. (default: search path "
56                     "for 'opt'.)"));
57 
58 /// writeProgramToFile - This writes the current "Program" to the named bitcode
59 /// file.  If an error occurs, true is returned.
60 ///
61 static bool writeProgramToFileAux(ToolOutputFile &Out, const Module *M) {
62   WriteBitcodeToFile(M, Out.os(), PreserveBitcodeUseListOrder);
63   Out.os().close();
64   if (!Out.os().has_error()) {
65     Out.keep();
66     return false;
67   }
68   return true;
69 }
70 
71 bool BugDriver::writeProgramToFile(const std::string &Filename, int FD,
72                                    const Module *M) const {
73   ToolOutputFile Out(Filename, FD);
74   return writeProgramToFileAux(Out, M);
75 }
76 
77 bool BugDriver::writeProgramToFile(const std::string &Filename,
78                                    const Module *M) const {
79   std::error_code EC;
80   ToolOutputFile Out(Filename, EC, sys::fs::F_None);
81   if (!EC)
82     return writeProgramToFileAux(Out, M);
83   return true;
84 }
85 
86 /// EmitProgressBitcode - This function is used to output the current Program
87 /// to a file named "bugpoint-ID.bc".
88 ///
89 void BugDriver::EmitProgressBitcode(const Module *M, const std::string &ID,
90                                     bool NoFlyer) const {
91   // Output the input to the current pass to a bitcode file, emit a message
92   // telling the user how to reproduce it: opt -foo blah.bc
93   //
94   std::string Filename = OutputPrefix + "-" + ID + ".bc";
95   if (writeProgramToFile(Filename, M)) {
96     errs() << "Error opening file '" << Filename << "' for writing!\n";
97     return;
98   }
99 
100   outs() << "Emitted bitcode to '" << Filename << "'\n";
101   if (NoFlyer || PassesToRun.empty())
102     return;
103   outs() << "\n*** You can reproduce the problem with: ";
104   if (UseValgrind)
105     outs() << "valgrind ";
106   outs() << "opt " << Filename;
107   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
108     outs() << " -load " << PluginLoader::getPlugin(i);
109   }
110   outs() << " " << getPassesString(PassesToRun) << "\n";
111 }
112 
113 cl::opt<bool> SilencePasses(
114     "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 ///
129 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()
141            << ": Error making unique filename: " << EC.message() << "\n";
142     return 1;
143   }
144   OutputFilename = UniqueFilename.str();
145 
146   // set up the input file name
147   Expected<sys::fs::TempFile> Temp =
148       sys::fs::TempFile::create(OutputPrefix + "-input-%%%%%%%.bc");
149   if (!Temp) {
150     errs() << getToolName()
151            << ": Error making unique filename: " << toString(Temp.takeError())
152            << "\n";
153     return 1;
154   }
155   DiscardTemp Discard{*Temp};
156   raw_fd_ostream OS(Temp->FD, /*shouldClose*/ false);
157 
158   WriteBitcodeToFile(Program, OS, PreserveBitcodeUseListOrder);
159   OS.flush();
160   if (OS.has_error()) {
161     errs() << "Error writing bitcode file: " << Temp->TmpName << "\n";
162     OS.clear_error();
163     return 1;
164   }
165 
166   std::string tool = OptCmd;
167   if (OptCmd.empty()) {
168     if (ErrorOr<std::string> Path = sys::findProgramByName("opt"))
169       tool = *Path;
170     else
171       errs() << Path.getError().message() << "\n";
172   }
173   if (tool.empty()) {
174     errs() << "Cannot find `opt' in PATH!\n";
175     return 1;
176   }
177 
178   std::string Prog;
179   if (UseValgrind) {
180     if (ErrorOr<std::string> Path = sys::findProgramByName("valgrind"))
181       Prog = *Path;
182     else
183       errs() << Path.getError().message() << "\n";
184   } else
185     Prog = tool;
186   if (Prog.empty()) {
187     errs() << "Cannot find `valgrind' in PATH!\n";
188     return 1;
189   }
190 
191   // setup the child process' arguments
192   SmallVector<const char *, 8> Args;
193   if (UseValgrind) {
194     Args.push_back("valgrind");
195     Args.push_back("--error-exitcode=1");
196     Args.push_back("-q");
197     Args.push_back(tool.c_str());
198   } else
199     Args.push_back(tool.c_str());
200 
201   for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
202     Args.push_back(OptArgs[i].c_str());
203   Args.push_back("-disable-symbolication");
204   Args.push_back("-o");
205   Args.push_back(OutputFilename.c_str());
206   std::vector<std::string> pass_args;
207   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
208     pass_args.push_back(std::string("-load"));
209     pass_args.push_back(PluginLoader::getPlugin(i));
210   }
211   for (std::vector<std::string>::const_iterator I = Passes.begin(),
212                                                 E = Passes.end();
213        I != E; ++I)
214     pass_args.push_back(std::string("-") + (*I));
215   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
216                                                 E = pass_args.end();
217        I != E; ++I)
218     Args.push_back(I->c_str());
219   Args.push_back(Temp->TmpName.c_str());
220   for (unsigned i = 0; i < NumExtraArgs; ++i)
221     Args.push_back(*ExtraArgs);
222   Args.push_back(nullptr);
223 
224   DEBUG(errs() << "\nAbout to run:\t";
225         for (unsigned i = 0, e = Args.size() - 1; i != e; ++i) errs()
226         << " " << Args[i];
227         errs() << "\n";);
228 
229   Optional<StringRef> Redirects[3] = {None, None, None};
230   // Redirect stdout and stderr to nowhere if SilencePasses is given.
231   if (SilencePasses) {
232     Redirects[1] = "";
233     Redirects[2] = "";
234   }
235 
236   std::string ErrMsg;
237   int result = sys::ExecuteAndWait(Prog, Args.data(), nullptr, Redirects,
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   consumeError(Temp->discard());
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 std::unique_ptr<Module>
268 BugDriver::runPassesOn(Module *M, const std::vector<std::string> &Passes,
269                        unsigned NumExtraArgs, const char *const *ExtraArgs) {
270   std::string BitcodeResult;
271   if (runPasses(M, Passes, BitcodeResult, false /*delete*/, true /*quiet*/,
272                 NumExtraArgs, ExtraArgs)) {
273     return nullptr;
274   }
275 
276   std::unique_ptr<Module> Ret = parseInputFile(BitcodeResult, Context);
277   if (!Ret) {
278     errs() << getToolName() << ": Error reading bitcode file '" << BitcodeResult
279            << "'!\n";
280     exit(1);
281   }
282   sys::fs::remove(BitcodeResult);
283   return Ret;
284 }
285