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 "SystemUtils.h"
13 #include "llvm/PassManager.h"
14 #include "llvm/Analysis/Verifier.h"
15 #include "llvm/Bytecode/WriteBytecodePass.h"
16 #include "llvm/Target/TargetData.h"
17 #include <sys/types.h>
18 #include <sys/wait.h>
19 #include <unistd.h>
20 #include <stdlib.h>
21 #include <fstream>
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 "bugpoing-ID.bc".
37 ///
38 void BugDriver::EmitProgressBytecode(const PassInfo *Pass,
39                                      const std::string &ID) {
40   // Output the input to the current pass to a bytecode file, emit a message
41   // telling the user how to reproduce it: opt -foo blah.bc
42   //
43   std::string Filename = "bugpoint-" + ID + ".bc";
44   if (writeProgramToFile(Filename)) {
45     std::cerr <<  "Error opening file '" << Filename << "' for writing!\n";
46     return;
47   }
48 
49   std::cout << "Emitted bytecode to '" << Filename << "'\n";
50   std::cout << "\n*** You can reproduce the problem with: ";
51 
52   unsigned PassType = Pass->getPassType();
53   if (PassType & PassInfo::Analysis)
54     std::cout << "analyze";
55   else if (PassType & PassInfo::Optimization)
56     std::cout << "opt";
57   else if (PassType & PassInfo::LLC)
58     std::cout << "llc";
59   else
60     std::cout << "bugpoint";
61   std::cout << " " << Filename << " -" << Pass->getPassArgument() << "\n";
62 }
63 
64 /// FIXME: This should be parameterizable!!
65 static TargetData TD("bugpoint target");
66 
67 static void RunChild(Module *Program,const std::vector<const PassInfo*> &Passes,
68                      const std::string &OutFilename) {
69   std::ofstream OutFile(OutFilename.c_str());
70   if (!OutFile.good()) {
71     std::cerr << "Error opening bytecode file: " << OutFilename << "\n";
72     exit(1);
73   }
74 
75   PassManager PM;
76   for (unsigned i = 0, e = Passes.size(); i != e; ++i) {
77     if (Passes[i]->getNormalCtor())
78       PM.add(Passes[i]->getNormalCtor()());
79     else if (Passes[i]->getDataCtor())
80       PM.add(Passes[i]->getDataCtor()(TD));    // Provide dummy target data...
81     else
82       std::cerr << "Cannot create pass yet: " << Passes[i]->getPassName()
83                 << "\n";
84   }
85   // Check that the module is well formed on completion of optimization
86   PM.add(createVerifierPass());
87 
88   // Write bytecode out to disk as the last step...
89   PM.add(new WriteBytecodePass(&OutFile));
90 
91   // Run all queued passes.
92   PM.run(*Program);
93 }
94 
95 /// runPasses - Run the specified passes on Program, outputting a bytecode file
96 /// and writting the filename into OutputFile if successful.  If the
97 /// optimizations fail for some reason (optimizer crashes), return true,
98 /// otherwise return false.  If DeleteOutput is set to true, the bytecode is
99 /// deleted on success, and the filename string is undefined.  This prints to
100 /// cout a single line message indicating whether compilation was successful or
101 /// failed.
102 ///
103 bool BugDriver::runPasses(const std::vector<const PassInfo*> &Passes,
104                           std::string &OutputFilename, bool DeleteOutput,
105 			  bool Quiet) const{
106   std::cout << std::flush;
107   OutputFilename = getUniqueFilename("bugpoint-output.bc");
108 
109   pid_t child_pid;
110   switch (child_pid = fork()) {
111   case -1:    // Error occurred
112     std::cerr << ToolName << ": Error forking!\n";
113     exit(1);
114   case 0:     // Child process runs passes.
115     RunChild(Program, Passes, OutputFilename);
116     exit(0);  // If we finish successfully, return 0!
117   default:    // Parent continues...
118     break;
119   }
120 
121   // Wait for the child process to get done.
122   int Status;
123   if (wait(&Status) != child_pid) {
124     std::cerr << "Error waiting for child process!\n";
125     exit(1);
126   }
127 
128   // If we are supposed to delete the bytecode file, remove it now
129   // unconditionally...  this may fail if the file was never created, but that's
130   // ok.
131   if (DeleteOutput)
132     removeFile(OutputFilename);
133 
134   if (!Quiet) std::cout << (Status ? "Crashed!\n" : "Success!\n");
135 
136   // Was the child successful?
137   return Status != 0;
138 }
139