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 ///
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 
72 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 
78 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 /// EmitProgressBitcode - This function is used to output the current Program
88 /// to a file named "bugpoint-ID.bc".
89 ///
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   SmallString<128> InputFilename;
149   int InputFD;
150   EC = sys::fs::createUniqueFile(OutputPrefix + "-input-%%%%%%%.bc", InputFD,
151                                  InputFilename);
152   if (EC) {
153     errs() << getToolName()
154            << ": Error making unique filename: " << EC.message() << "\n";
155     return 1;
156   }
157 
158   tool_output_file InFile(InputFilename, InputFD);
159 
160   WriteBitcodeToFile(Program, InFile.os(), PreserveBitcodeUseListOrder);
161   InFile.os().close();
162   if (InFile.os().has_error()) {
163     errs() << "Error writing bitcode file: " << InputFilename << "\n";
164     InFile.os().clear_error();
165     return 1;
166   }
167 
168   std::string tool = OptCmd;
169   if (OptCmd.empty()) {
170     if (ErrorOr<std::string> Path = sys::findProgramByName("opt"))
171       tool = *Path;
172     else
173       errs() << Path.getError().message() << "\n";
174   }
175   if (tool.empty()) {
176     errs() << "Cannot find `opt' in PATH!\n";
177     return 1;
178   }
179 
180   std::string Prog;
181   if (UseValgrind) {
182     if (ErrorOr<std::string> Path = sys::findProgramByName("valgrind"))
183       Prog = *Path;
184     else
185       errs() << Path.getError().message() << "\n";
186   } else
187     Prog = tool;
188   if (Prog.empty()) {
189     errs() << "Cannot find `valgrind' in PATH!\n";
190     return 1;
191   }
192 
193   // Ok, everything that could go wrong before running opt is done.
194   InFile.keep();
195 
196   // setup the child process' arguments
197   SmallVector<const char *, 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.c_str());
203   } else
204     Args.push_back(tool.c_str());
205 
206   Args.push_back("-o");
207   Args.push_back(OutputFilename.c_str());
208   for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
209     Args.push_back(OptArgs[i].c_str());
210   std::vector<std::string> pass_args;
211   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
212     pass_args.push_back(std::string("-load"));
213     pass_args.push_back(PluginLoader::getPlugin(i));
214   }
215   for (std::vector<std::string>::const_iterator I = Passes.begin(),
216                                                 E = Passes.end();
217        I != E; ++I)
218     pass_args.push_back(std::string("-") + (*I));
219   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
220                                                 E = pass_args.end();
221        I != E; ++I)
222     Args.push_back(I->c_str());
223   Args.push_back(InputFilename.c_str());
224   for (unsigned i = 0; i < NumExtraArgs; ++i)
225     Args.push_back(*ExtraArgs);
226   Args.push_back(nullptr);
227 
228   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   // Redirect stdout and stderr to nowhere if SilencePasses is given
234   StringRef Nowhere;
235   const StringRef *Redirects[3] = {nullptr, &Nowhere, &Nowhere};
236 
237   std::string ErrMsg;
238   int result = sys::ExecuteAndWait(Prog, Args.data(), nullptr,
239                                    (SilencePasses ? Redirects : nullptr),
240                                    Timeout, MemoryLimit, &ErrMsg);
241 
242   // If we are supposed to delete the bitcode file or if the passes crashed,
243   // remove it now.  This may fail if the file was never created, but that's ok.
244   if (DeleteOutput || result != 0)
245     sys::fs::remove(OutputFilename);
246 
247   // Remove the temporary input file as well
248   sys::fs::remove(InputFilename.c_str());
249 
250   if (!Quiet) {
251     if (result == 0)
252       outs() << "Success!\n";
253     else if (result > 0)
254       outs() << "Exited with error code '" << result << "'\n";
255     else if (result < 0) {
256       if (result == -1)
257         outs() << "Execute failed: " << ErrMsg << "\n";
258       else
259         outs() << "Crashed: " << ErrMsg << "\n";
260     }
261     if (result & 0x01000000)
262       outs() << "Dumped core\n";
263   }
264 
265   // Was the child successful?
266   return result != 0;
267 }
268 
269 std::unique_ptr<Module>
270 BugDriver::runPassesOn(Module *M, const std::vector<std::string> &Passes,
271                        unsigned NumExtraArgs, const char *const *ExtraArgs) {
272   std::string BitcodeResult;
273   if (runPasses(M, Passes, BitcodeResult, false /*delete*/, true /*quiet*/,
274                 NumExtraArgs, ExtraArgs)) {
275     return nullptr;
276   }
277 
278   std::unique_ptr<Module> Ret = parseInputFile(BitcodeResult, Context);
279   if (!Ret) {
280     errs() << getToolName() << ": Error reading bitcode file '" << BitcodeResult
281            << "'!\n";
282     exit(1);
283   }
284   sys::fs::remove(BitcodeResult);
285   return Ret;
286 }
287