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 "ToolRunner.h"
20 #include "llvm/Bitcode/BitcodeWriter.h"
21 #include "llvm/IR/DataLayout.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/Support/CommandLine.h"
24 #include "llvm/Support/Debug.h"
25 #include "llvm/Support/FileUtilities.h"
26 #include "llvm/Support/Path.h"
27 #include "llvm/Support/Program.h"
28 #include "llvm/Support/ToolOutputFile.h"
29 
30 #define DONT_GET_PLUGIN_LOADER_OPTION
31 #include "llvm/Support/PluginLoader.h"
32 
33 
34 using namespace llvm;
35 
36 #define DEBUG_TYPE "bugpoint"
37 
38 namespace llvm {
39 extern cl::opt<std::string> OutputPrefix;
40 }
41 
42 static cl::opt<bool> PreserveBitcodeUseListOrder(
43     "preserve-bc-uselistorder",
44     cl::desc("Preserve use-list order when writing LLVM bitcode."),
45     cl::init(true), cl::Hidden);
46 
47 static cl::opt<std::string>
48     OptCmd("opt-command", cl::init(""),
49            cl::desc("Path to opt. (default: search path "
50                     "for 'opt'.)"));
51 
52 /// This writes the current "Program" to the named bitcode file.  If an error
53 /// occurs, true is returned.
54 static bool writeProgramToFileAux(ToolOutputFile &Out, const Module &M) {
55   WriteBitcodeToFile(M, Out.os(), PreserveBitcodeUseListOrder);
56   Out.os().close();
57   if (!Out.os().has_error()) {
58     Out.keep();
59     return false;
60   }
61   return true;
62 }
63 
64 bool BugDriver::writeProgramToFile(const std::string &Filename, int FD,
65                                    const Module &M) const {
66   ToolOutputFile Out(Filename, FD);
67   return writeProgramToFileAux(Out, M);
68 }
69 
70 bool BugDriver::writeProgramToFile(int FD, const Module &M) const {
71   raw_fd_ostream OS(FD, /*shouldClose*/ false);
72   WriteBitcodeToFile(M, OS, PreserveBitcodeUseListOrder);
73   OS.flush();
74   if (!OS.has_error())
75     return false;
76   OS.clear_error();
77   return true;
78 }
79 
80 bool BugDriver::writeProgramToFile(const std::string &Filename,
81                                    const Module &M) const {
82   std::error_code EC;
83   ToolOutputFile Out(Filename, EC, sys::fs::F_None);
84   if (!EC)
85     return writeProgramToFileAux(Out, M);
86   return true;
87 }
88 
89 /// This function is used to output the current Program to a file named
90 /// "bugpoint-ID.bc".
91 void BugDriver::EmitProgressBitcode(const Module &M, const std::string &ID,
92                                     bool NoFlyer) const {
93   // Output the input to the current pass to a bitcode file, emit a message
94   // telling the user how to reproduce it: opt -foo blah.bc
95   //
96   std::string Filename = OutputPrefix + "-" + ID + ".bc";
97   if (writeProgramToFile(Filename, M)) {
98     errs() << "Error opening file '" << Filename << "' for writing!\n";
99     return;
100   }
101 
102   outs() << "Emitted bitcode to '" << Filename << "'\n";
103   if (NoFlyer || PassesToRun.empty())
104     return;
105   outs() << "\n*** You can reproduce the problem with: ";
106   if (UseValgrind)
107     outs() << "valgrind ";
108   outs() << "opt " << Filename;
109   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
110     outs() << " -load " << PluginLoader::getPlugin(i);
111   }
112   outs() << " " << getPassesString(PassesToRun) << "\n";
113 }
114 
115 cl::opt<bool> SilencePasses(
116     "silence-passes",
117     cl::desc("Suppress output of running passes (both stdout and stderr)"));
118 
119 static cl::list<std::string> OptArgs("opt-args", cl::Positional,
120                                      cl::desc("<opt arguments>..."),
121                                      cl::ZeroOrMore, cl::PositionalEatsArgs);
122 
123 /// runPasses - Run the specified passes on Program, outputting a bitcode file
124 /// and writing the filename into OutputFile if successful.  If the
125 /// optimizations fail for some reason (optimizer crashes), return true,
126 /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
127 /// deleted on success, and the filename string is undefined.  This prints to
128 /// outs() a single line message indicating whether compilation was successful
129 /// or failed.
130 ///
131 bool BugDriver::runPasses(Module &Program,
132                           const std::vector<std::string> &Passes,
133                           std::string &OutputFilename, bool DeleteOutput,
134                           bool Quiet, unsigned NumExtraArgs,
135                           const char *const *ExtraArgs) const {
136   // setup the output file name
137   outs().flush();
138   SmallString<128> UniqueFilename;
139   std::error_code EC = sys::fs::createUniqueFile(
140       OutputPrefix + "-output-%%%%%%%.bc", UniqueFilename);
141   if (EC) {
142     errs() << getToolName()
143            << ": Error making unique filename: " << EC.message() << "\n";
144     return 1;
145   }
146   OutputFilename = UniqueFilename.str();
147 
148   // set up the input file name
149   Expected<sys::fs::TempFile> Temp =
150       sys::fs::TempFile::create(OutputPrefix + "-input-%%%%%%%.bc");
151   if (!Temp) {
152     errs() << getToolName()
153            << ": Error making unique filename: " << toString(Temp.takeError())
154            << "\n";
155     return 1;
156   }
157   DiscardTemp Discard{*Temp};
158   raw_fd_ostream OS(Temp->FD, /*shouldClose*/ false);
159 
160   WriteBitcodeToFile(Program, OS, PreserveBitcodeUseListOrder);
161   OS.flush();
162   if (OS.has_error()) {
163     errs() << "Error writing bitcode file: " << Temp->TmpName << "\n";
164     OS.clear_error();
165     return 1;
166   }
167 
168   std::string tool = OptCmd;
169   if (OptCmd.empty()) {
170     if (ErrorOr<std::string> Path =
171             FindProgramByName("opt", getToolName(), &OutputPrefix))
172       tool = *Path;
173     else
174       errs() << Path.getError().message() << "\n";
175   }
176   if (tool.empty()) {
177     errs() << "Cannot find `opt' in PATH!\n";
178     return 1;
179   }
180   if (!sys::fs::exists(tool)) {
181     errs() << "Specified `opt' binary does not exist: " << tool << "\n";
182     return 1;
183   }
184 
185   std::string Prog;
186   if (UseValgrind) {
187     if (ErrorOr<std::string> Path = sys::findProgramByName("valgrind"))
188       Prog = *Path;
189     else
190       errs() << Path.getError().message() << "\n";
191   } else
192     Prog = tool;
193   if (Prog.empty()) {
194     errs() << "Cannot find `valgrind' in PATH!\n";
195     return 1;
196   }
197 
198   // setup the child process' arguments
199   SmallVector<StringRef, 8> Args;
200   if (UseValgrind) {
201     Args.push_back("valgrind");
202     Args.push_back("--error-exitcode=1");
203     Args.push_back("-q");
204     Args.push_back(tool);
205   } else
206     Args.push_back(tool);
207 
208   for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
209     Args.push_back(OptArgs[i]);
210   Args.push_back("-disable-symbolication");
211   Args.push_back("-o");
212   Args.push_back(OutputFilename);
213   std::vector<std::string> pass_args;
214   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
215     pass_args.push_back(std::string("-load"));
216     pass_args.push_back(PluginLoader::getPlugin(i));
217   }
218   for (std::vector<std::string>::const_iterator I = Passes.begin(),
219                                                 E = Passes.end();
220        I != E; ++I)
221     pass_args.push_back(std::string("-") + (*I));
222   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
223                                                 E = pass_args.end();
224        I != E; ++I)
225     Args.push_back(I->c_str());
226   Args.push_back(Temp->TmpName.c_str());
227   for (unsigned i = 0; i < NumExtraArgs; ++i)
228     Args.push_back(*ExtraArgs);
229 
230   LLVM_DEBUG(errs() << "\nAbout to run:\t";
231              for (unsigned i = 0, e = Args.size() - 1; i != e; ++i) errs()
232              << " " << Args[i];
233              errs() << "\n";);
234 
235   Optional<StringRef> Redirects[3] = {None, None, None};
236   // Redirect stdout and stderr to nowhere if SilencePasses is given.
237   if (SilencePasses) {
238     Redirects[1] = "";
239     Redirects[2] = "";
240   }
241 
242   std::string ErrMsg;
243   int result = sys::ExecuteAndWait(Prog, Args, None, Redirects, Timeout,
244                                    MemoryLimit, &ErrMsg);
245 
246   // If we are supposed to delete the bitcode file or if the passes crashed,
247   // remove it now.  This may fail if the file was never created, but that's ok.
248   if (DeleteOutput || result != 0)
249     sys::fs::remove(OutputFilename);
250 
251   if (!Quiet) {
252     if (result == 0)
253       outs() << "Success!\n";
254     else if (result > 0)
255       outs() << "Exited with error code '" << result << "'\n";
256     else if (result < 0) {
257       if (result == -1)
258         outs() << "Execute failed: " << ErrMsg << "\n";
259       else
260         outs() << "Crashed: " << ErrMsg << "\n";
261     }
262     if (result & 0x01000000)
263       outs() << "Dumped core\n";
264   }
265 
266   // Was the child successful?
267   return result != 0;
268 }
269 
270 std::unique_ptr<Module>
271 BugDriver::runPassesOn(Module *M, const std::vector<std::string> &Passes,
272                        unsigned NumExtraArgs, const char *const *ExtraArgs) {
273   std::string BitcodeResult;
274   if (runPasses(*M, Passes, BitcodeResult, false /*delete*/, true /*quiet*/,
275                 NumExtraArgs, ExtraArgs)) {
276     return nullptr;
277   }
278 
279   std::unique_ptr<Module> Ret = parseInputFile(BitcodeResult, Context);
280   if (!Ret) {
281     errs() << getToolName() << ": Error reading bitcode file '" << BitcodeResult
282            << "'!\n";
283     exit(1);
284   }
285   sys::fs::remove(BitcodeResult);
286   return Ret;
287 }
288