1 //===- OptimizerDriver.cpp - Allow BugPoint to run passes safely ----------===//
2 //
3 // This file defines an interface that allows bugpoint to run various passes
4 // without the threat of a buggy pass corrupting bugpoint (of course bugpoint
5 // may have it's own bugs, but that's another story...).  It acheives this by
6 // forking a copy of itself and having the child process do the optimizations.
7 // If this client dies, we can always fork a new one.  :)
8 //
9 //===----------------------------------------------------------------------===//
10 
11 #include "BugDriver.h"
12 #include "llvm/PassManager.h"
13 #include "llvm/Analysis/Verifier.h"
14 #include "llvm/Bytecode/WriteBytecodePass.h"
15 #include "llvm/Target/TargetData.h"
16 #include "Support/FileUtilities.h"
17 #include <fstream>
18 #include <stdlib.h>
19 #include <unistd.h>
20 #include <sys/types.h>
21 #include <sys/wait.h>
22 
23 /// writeProgramToFile - This writes the current "Program" to the named bytecode
24 /// file.  If an error occurs, true is returned.
25 ///
26 bool BugDriver::writeProgramToFile(const std::string &Filename,
27 				   Module *M) const {
28   std::ofstream Out(Filename.c_str());
29   if (!Out.good()) return true;
30   WriteBytecodeToFile(M ? M : Program, Out);
31   return false;
32 }
33 
34 
35 /// EmitProgressBytecode - This function is used to output the current Program
36 /// to a file named "bugpoint-ID.bc".
37 ///
38 void BugDriver::EmitProgressBytecode(const std::string &ID, bool NoFlyer) {
39   // Output the input to the current pass to a bytecode file, emit a message
40   // telling the user how to reproduce it: opt -foo blah.bc
41   //
42   std::string Filename = "bugpoint-" + ID + ".bc";
43   if (writeProgramToFile(Filename)) {
44     std::cerr <<  "Error opening file '" << Filename << "' for writing!\n";
45     return;
46   }
47 
48   std::cout << "Emitted bytecode to '" << Filename << "'\n";
49   if (NoFlyer) return;
50   std::cout << "\n*** You can reproduce the problem with: ";
51 
52   unsigned PassType = PassesToRun[0]->getPassType();
53   for (unsigned i = 1, e = PassesToRun.size(); i != e; ++i)
54     PassType &= PassesToRun[i]->getPassType();
55 
56   if (PassType & PassInfo::Analysis)
57     std::cout << "analyze";
58   else if (PassType & PassInfo::Optimization)
59     std::cout << "opt";
60   else if (PassType & PassInfo::LLC)
61     std::cout << "llc";
62   else
63     std::cout << "bugpoint";
64   std::cout << " " << Filename << " ";
65   std::cout << getPassesString(PassesToRun) << "\n";
66 }
67 
68 static void RunChild(Module *Program,const std::vector<const PassInfo*> &Passes,
69                      const std::string &OutFilename) {
70   std::ofstream OutFile(OutFilename.c_str());
71   if (!OutFile.good()) {
72     std::cerr << "Error opening bytecode file: " << OutFilename << "\n";
73     exit(1);
74   }
75 
76   PassManager PM;
77   // Make sure that the appropriate target data is always used...
78   PM.add(new TargetData("bugpoint", Program));
79 
80   for (unsigned i = 0, e = Passes.size(); i != e; ++i) {
81     if (Passes[i]->getNormalCtor())
82       PM.add(Passes[i]->getNormalCtor()());
83     else
84       std::cerr << "Cannot create pass yet: " << Passes[i]->getPassName()
85                 << "\n";
86   }
87   // Check that the module is well formed on completion of optimization
88   PM.add(createVerifierPass());
89 
90   // Write bytecode out to disk as the last step...
91   PM.add(new WriteBytecodePass(&OutFile));
92 
93   // Run all queued passes.
94   PM.run(*Program);
95 }
96 
97 /// runPasses - Run the specified passes on Program, outputting a bytecode file
98 /// and writting the filename into OutputFile if successful.  If the
99 /// optimizations fail for some reason (optimizer crashes), return true,
100 /// otherwise return false.  If DeleteOutput is set to true, the bytecode is
101 /// deleted on success, and the filename string is undefined.  This prints to
102 /// cout a single line message indicating whether compilation was successful or
103 /// failed.
104 ///
105 bool BugDriver::runPasses(const std::vector<const PassInfo*> &Passes,
106                           std::string &OutputFilename, bool DeleteOutput,
107 			  bool Quiet) const{
108   std::cout << std::flush;
109   OutputFilename = getUniqueFilename("bugpoint-output.bc");
110 
111   pid_t child_pid;
112   switch (child_pid = fork()) {
113   case -1:    // Error occurred
114     std::cerr << ToolName << ": Error forking!\n";
115     exit(1);
116   case 0:     // Child process runs passes.
117     RunChild(Program, Passes, OutputFilename);
118     exit(0);  // If we finish successfully, return 0!
119   default:    // Parent continues...
120     break;
121   }
122 
123   // Wait for the child process to get done.
124   int Status;
125   if (wait(&Status) != child_pid) {
126     std::cerr << "Error waiting for child process!\n";
127     exit(1);
128   }
129 
130   // If we are supposed to delete the bytecode file, remove it now
131   // unconditionally...  this may fail if the file was never created, but that's
132   // ok.
133   if (DeleteOutput)
134     removeFile(OutputFilename);
135 
136   bool ExitedOK = WIFEXITED(Status) && WEXITSTATUS(Status) == 0;
137 
138   if (!Quiet) {
139     if (ExitedOK)
140       std::cout << "Success!\n";
141     else if (WIFEXITED(Status))
142       std::cout << "Exited with error code '" << WEXITSTATUS(Status) << "'\n";
143     else if (WIFSIGNALED(Status))
144       std::cout << "Crashed with signal #" << WTERMSIG(Status) << "\n";
145 #ifdef WCOREDUMP
146     else if (WCOREDUMP(Status))
147       std::cout << "Dumped core\n";
148 #endif
149     else
150       std::cout << "Failed for unknown reason!\n";
151   }
152 
153   // Was the child successful?
154   return !ExitedOK;
155 }
156