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/Module.h"
22 #include "llvm/Support/CommandLine.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/FileUtilities.h"
25 #include "llvm/Support/Path.h"
26 #include "llvm/Support/Program.h"
27 #include "llvm/Support/ToolOutputFile.h"
28 
29 #define DONT_GET_PLUGIN_LOADER_OPTION
30 #include "llvm/Support/PluginLoader.h"
31 
32 
33 using namespace llvm;
34 
35 #define DEBUG_TYPE "bugpoint"
36 
37 namespace llvm {
38 extern cl::opt<std::string> OutputPrefix;
39 }
40 
41 static cl::opt<bool> PreserveBitcodeUseListOrder(
42     "preserve-bc-uselistorder",
43     cl::desc("Preserve use-list order when writing LLVM bitcode."),
44     cl::init(true), cl::Hidden);
45 
46 static cl::opt<std::string>
47     OptCmd("opt-command", cl::init(""),
48            cl::desc("Path to opt. (default: search path "
49                     "for 'opt'.)"));
50 
51 /// This writes the current "Program" to the named bitcode file.  If an error
52 /// occurs, true is returned.
53 static bool writeProgramToFileAux(ToolOutputFile &Out, const Module &M) {
54   WriteBitcodeToFile(M, Out.os(), PreserveBitcodeUseListOrder);
55   Out.os().close();
56   if (!Out.os().has_error()) {
57     Out.keep();
58     return false;
59   }
60   return true;
61 }
62 
63 bool BugDriver::writeProgramToFile(const std::string &Filename, int FD,
64                                    const Module &M) const {
65   ToolOutputFile Out(Filename, FD);
66   return writeProgramToFileAux(Out, M);
67 }
68 
69 bool BugDriver::writeProgramToFile(int FD, const Module &M) const {
70   raw_fd_ostream OS(FD, /*shouldClose*/ false);
71   WriteBitcodeToFile(M, OS, PreserveBitcodeUseListOrder);
72   OS.flush();
73   if (!OS.has_error())
74     return false;
75   OS.clear_error();
76   return true;
77 }
78 
79 bool BugDriver::writeProgramToFile(const std::string &Filename,
80                                    const Module &M) const {
81   std::error_code EC;
82   ToolOutputFile Out(Filename, EC, sys::fs::F_None);
83   if (!EC)
84     return writeProgramToFileAux(Out, M);
85   return true;
86 }
87 
88 /// This function is used to output the current Program to a file named
89 /// "bugpoint-ID.bc".
90 void BugDriver::EmitProgressBitcode(const Module &M, const std::string &ID,
91                                     bool NoFlyer) const {
92   // Output the input to the current pass to a bitcode file, emit a message
93   // telling the user how to reproduce it: opt -foo blah.bc
94   //
95   std::string Filename = OutputPrefix + "-" + ID + ".bc";
96   if (writeProgramToFile(Filename, M)) {
97     errs() << "Error opening file '" << Filename << "' for writing!\n";
98     return;
99   }
100 
101   outs() << "Emitted bitcode to '" << Filename << "'\n";
102   if (NoFlyer || PassesToRun.empty())
103     return;
104   outs() << "\n*** You can reproduce the problem with: ";
105   if (UseValgrind)
106     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(
115     "silence-passes",
116     cl::desc("Suppress output of running passes (both stdout and stderr)"));
117 
118 static cl::list<std::string> OptArgs("opt-args", cl::Positional,
119                                      cl::desc("<opt arguments>..."),
120                                      cl::ZeroOrMore, cl::PositionalEatsArgs);
121 
122 /// runPasses - Run the specified passes on Program, outputting a bitcode file
123 /// and writing the filename into OutputFile if successful.  If the
124 /// optimizations fail for some reason (optimizer crashes), return true,
125 /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
126 /// deleted on success, and the filename string is undefined.  This prints to
127 /// outs() a single line message indicating whether compilation was successful
128 /// or failed.
129 ///
130 bool BugDriver::runPasses(Module &Program,
131                           const std::vector<std::string> &Passes,
132                           std::string &OutputFilename, bool DeleteOutput,
133                           bool Quiet, unsigned NumExtraArgs,
134                           const char *const *ExtraArgs) const {
135   // setup the output file name
136   outs().flush();
137   SmallString<128> UniqueFilename;
138   std::error_code EC = sys::fs::createUniqueFile(
139       OutputPrefix + "-output-%%%%%%%.bc", UniqueFilename);
140   if (EC) {
141     errs() << getToolName()
142            << ": Error making unique filename: " << EC.message() << "\n";
143     return 1;
144   }
145   OutputFilename = UniqueFilename.str();
146 
147   // set up the input file name
148   Expected<sys::fs::TempFile> Temp =
149       sys::fs::TempFile::create(OutputPrefix + "-input-%%%%%%%.bc");
150   if (!Temp) {
151     errs() << getToolName()
152            << ": Error making unique filename: " << toString(Temp.takeError())
153            << "\n";
154     return 1;
155   }
156   DiscardTemp Discard{*Temp};
157   raw_fd_ostream OS(Temp->FD, /*shouldClose*/ false);
158 
159   WriteBitcodeToFile(Program, OS, PreserveBitcodeUseListOrder);
160   OS.flush();
161   if (OS.has_error()) {
162     errs() << "Error writing bitcode file: " << Temp->TmpName << "\n";
163     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   if (!sys::fs::exists(tool)) {
179     errs() << "Specified `opt' binary does not exist: " << tool << "\n";
180     return 1;
181   }
182 
183   std::string Prog;
184   if (UseValgrind) {
185     if (ErrorOr<std::string> Path = sys::findProgramByName("valgrind"))
186       Prog = *Path;
187     else
188       errs() << Path.getError().message() << "\n";
189   } else
190     Prog = tool;
191   if (Prog.empty()) {
192     errs() << "Cannot find `valgrind' in PATH!\n";
193     return 1;
194   }
195 
196   // setup the child process' arguments
197   SmallVector<StringRef, 8> Args;
198   if (UseValgrind) {
199     Args.push_back("valgrind");
200     Args.push_back("--error-exitcode=1");
201     Args.push_back("-q");
202     Args.push_back(tool);
203   } else
204     Args.push_back(tool);
205 
206   for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
207     Args.push_back(OptArgs[i]);
208   Args.push_back("-disable-symbolication");
209   Args.push_back("-o");
210   Args.push_back(OutputFilename);
211   std::vector<std::string> pass_args;
212   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
213     pass_args.push_back(std::string("-load"));
214     pass_args.push_back(PluginLoader::getPlugin(i));
215   }
216   for (std::vector<std::string>::const_iterator I = Passes.begin(),
217                                                 E = Passes.end();
218        I != E; ++I)
219     pass_args.push_back(std::string("-") + (*I));
220   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
221                                                 E = pass_args.end();
222        I != E; ++I)
223     Args.push_back(I->c_str());
224   Args.push_back(Temp->TmpName.c_str());
225   for (unsigned i = 0; i < NumExtraArgs; ++i)
226     Args.push_back(*ExtraArgs);
227 
228   LLVM_DEBUG(errs() << "\nAbout to run:\t";
229              for (unsigned i = 0, e = Args.size() - 1; i != e; ++i) errs()
230              << " " << Args[i];
231              errs() << "\n";);
232 
233   Optional<StringRef> Redirects[3] = {None, None, None};
234   // Redirect stdout and stderr to nowhere if SilencePasses is given.
235   if (SilencePasses) {
236     Redirects[1] = "";
237     Redirects[2] = "";
238   }
239 
240   std::string ErrMsg;
241   int result = sys::ExecuteAndWait(Prog, Args, None, Redirects, Timeout,
242                                    MemoryLimit, &ErrMsg);
243 
244   // If we are supposed to delete the bitcode file or if the passes crashed,
245   // remove it now.  This may fail if the file was never created, but that's ok.
246   if (DeleteOutput || result != 0)
247     sys::fs::remove(OutputFilename);
248 
249   if (!Quiet) {
250     if (result == 0)
251       outs() << "Success!\n";
252     else if (result > 0)
253       outs() << "Exited with error code '" << result << "'\n";
254     else if (result < 0) {
255       if (result == -1)
256         outs() << "Execute failed: " << ErrMsg << "\n";
257       else
258         outs() << "Crashed: " << ErrMsg << "\n";
259     }
260     if (result & 0x01000000)
261       outs() << "Dumped core\n";
262   }
263 
264   // Was the child successful?
265   return result != 0;
266 }
267 
268 std::unique_ptr<Module>
269 BugDriver::runPassesOn(Module *M, const std::vector<std::string> &Passes,
270                        unsigned NumExtraArgs, const char *const *ExtraArgs) {
271   std::string BitcodeResult;
272   if (runPasses(*M, Passes, BitcodeResult, false /*delete*/, true /*quiet*/,
273                 NumExtraArgs, ExtraArgs)) {
274     return nullptr;
275   }
276 
277   std::unique_ptr<Module> Ret = parseInputFile(BitcodeResult, Context);
278   if (!Ret) {
279     errs() << getToolName() << ": Error reading bitcode file '" << BitcodeResult
280            << "'!\n";
281     exit(1);
282   }
283   sys::fs::remove(BitcodeResult);
284   return Ret;
285 }
286