Cleanup some comments in the OCaml bindings.
[oota-llvm.git] / tools / bugpoint / ToolRunner.cpp
1 //===-- ToolRunner.cpp ----------------------------------------------------===//
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 implements the interfaces described in the ToolRunner.h file.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #define DEBUG_TYPE "toolrunner"
15 #include "ToolRunner.h"
16 #include "llvm/Config/config.h"   // for HAVE_LINK_R
17 #include "llvm/System/Program.h"
18 #include "llvm/Support/CommandLine.h"
19 #include "llvm/Support/Debug.h"
20 #include "llvm/Support/FileUtilities.h"
21 #include <fstream>
22 #include <sstream>
23 #include <iostream>
24 using namespace llvm;
25
26 namespace {
27   cl::opt<std::string>
28   RSHHost("rsh-host",
29           cl::desc("Remote execution (rsh) host"));
30
31   cl::opt<std::string>
32   RSHUser("rsh-user",
33           cl::desc("Remote execution (rsh) user id"));
34 }
35
36 ToolExecutionError::~ToolExecutionError() throw() { }
37
38 /// RunProgramWithTimeout - This function provides an alternate interface to the
39 /// sys::Program::ExecuteAndWait interface.
40 /// @see sys:Program::ExecuteAndWait
41 static int RunProgramWithTimeout(const sys::Path &ProgramPath,
42                                  const char **Args,
43                                  const sys::Path &StdInFile,
44                                  const sys::Path &StdOutFile,
45                                  const sys::Path &StdErrFile,
46                                  unsigned NumSeconds = 0,
47                                  unsigned MemoryLimit = 0) {
48   const sys::Path* redirects[3];
49   redirects[0] = &StdInFile;
50   redirects[1] = &StdOutFile;
51   redirects[2] = &StdErrFile;
52                                    
53   if (0) {
54     std::cerr << "RUN:";
55     for (unsigned i = 0; Args[i]; ++i)
56       std::cerr << " " << Args[i];
57     std::cerr << "\n";
58   }
59
60   return
61     sys::Program::ExecuteAndWait(ProgramPath, Args, 0, redirects,
62                                  NumSeconds, MemoryLimit);
63 }
64
65
66
67 static void ProcessFailure(sys::Path ProgPath, const char** Args) {
68   std::ostringstream OS;
69   OS << "\nError running tool:\n ";
70   for (const char **Arg = Args; *Arg; ++Arg)
71     OS << " " << *Arg;
72   OS << "\n";
73
74   // Rerun the compiler, capturing any error messages to print them.
75   sys::Path ErrorFilename("error_messages");
76   std::string ErrMsg;
77   if (ErrorFilename.makeUnique(true, &ErrMsg)) {
78     std::cerr << "Error making unique filename: " << ErrMsg << "\n";
79     exit(1);
80   }
81   RunProgramWithTimeout(ProgPath, Args, sys::Path(""), ErrorFilename,
82                         ErrorFilename); // FIXME: check return code ?
83
84   // Print out the error messages generated by GCC if possible...
85   std::ifstream ErrorFile(ErrorFilename.c_str());
86   if (ErrorFile) {
87     std::copy(std::istreambuf_iterator<char>(ErrorFile),
88               std::istreambuf_iterator<char>(),
89               std::ostreambuf_iterator<char>(OS));
90     ErrorFile.close();
91   }
92
93   ErrorFilename.eraseFromDisk();
94   throw ToolExecutionError(OS.str());
95 }
96
97 //===---------------------------------------------------------------------===//
98 // LLI Implementation of AbstractIntepreter interface
99 //
100 namespace {
101   class LLI : public AbstractInterpreter {
102     std::string LLIPath;          // The path to the LLI executable
103     std::vector<std::string> ToolArgs; // Args to pass to LLI
104   public:
105     LLI(const std::string &Path, const std::vector<std::string> *Args)
106       : LLIPath(Path) {
107       ToolArgs.clear ();
108       if (Args) { ToolArgs = *Args; }
109     }
110
111     virtual int ExecuteProgram(const std::string &Bitcode,
112                                const std::vector<std::string> &Args,
113                                const std::string &InputFile,
114                                const std::string &OutputFile,
115                                const std::vector<std::string> &GCCArgs,
116                                const std::vector<std::string> &SharedLibs =
117                                std::vector<std::string>(),
118                                unsigned Timeout = 0,
119                                unsigned MemoryLimit = 0);
120   };
121 }
122
123 int LLI::ExecuteProgram(const std::string &Bitcode,
124                         const std::vector<std::string> &Args,
125                         const std::string &InputFile,
126                         const std::string &OutputFile,
127                         const std::vector<std::string> &GCCArgs,
128                         const std::vector<std::string> &SharedLibs,
129                         unsigned Timeout,
130                         unsigned MemoryLimit) {
131   if (!SharedLibs.empty())
132     throw ToolExecutionError("LLI currently does not support "
133                              "loading shared libraries.");
134
135   if (!GCCArgs.empty())
136     throw ToolExecutionError("LLI currently does not support "
137                              "GCC Arguments.");
138   std::vector<const char*> LLIArgs;
139   LLIArgs.push_back(LLIPath.c_str());
140   LLIArgs.push_back("-force-interpreter=true");
141
142   // Add any extra LLI args.
143   for (unsigned i = 0, e = ToolArgs.size(); i != e; ++i)
144     LLIArgs.push_back(ToolArgs[i].c_str());
145
146   LLIArgs.push_back(Bitcode.c_str());
147   // Add optional parameters to the running program from Argv
148   for (unsigned i=0, e = Args.size(); i != e; ++i)
149     LLIArgs.push_back(Args[i].c_str());
150   LLIArgs.push_back(0);
151
152   std::cout << "<lli>" << std::flush;
153   DEBUG(std::cerr << "\nAbout to run:\t";
154         for (unsigned i=0, e = LLIArgs.size()-1; i != e; ++i)
155           std::cerr << " " << LLIArgs[i];
156         std::cerr << "\n";
157         );
158   return RunProgramWithTimeout(sys::Path(LLIPath), &LLIArgs[0],
159       sys::Path(InputFile), sys::Path(OutputFile), sys::Path(OutputFile),
160       Timeout, MemoryLimit);
161 }
162
163 // LLI create method - Try to find the LLI executable
164 AbstractInterpreter *AbstractInterpreter::createLLI(const std::string &ProgPath,
165                                                     std::string &Message,
166                                      const std::vector<std::string> *ToolArgs) {
167   std::string LLIPath = FindExecutable("lli", ProgPath).toString();
168   if (!LLIPath.empty()) {
169     Message = "Found lli: " + LLIPath + "\n";
170     return new LLI(LLIPath, ToolArgs);
171   }
172
173   Message = "Cannot find `lli' in executable directory or PATH!\n";
174   return 0;
175 }
176
177 //===----------------------------------------------------------------------===//
178 // LLC Implementation of AbstractIntepreter interface
179 //
180 GCC::FileType LLC::OutputCode(const std::string &Bitcode, 
181                               sys::Path &OutputAsmFile) {
182   sys::Path uniqueFile(Bitcode+".llc.s");
183   std::string ErrMsg;
184   if (uniqueFile.makeUnique(true, &ErrMsg)) {
185     std::cerr << "Error making unique filename: " << ErrMsg << "\n";
186     exit(1);
187   }
188   OutputAsmFile = uniqueFile;
189   std::vector<const char *> LLCArgs;
190   LLCArgs.push_back (LLCPath.c_str());
191
192   // Add any extra LLC args.
193   for (unsigned i = 0, e = ToolArgs.size(); i != e; ++i)
194     LLCArgs.push_back(ToolArgs[i].c_str());
195
196   LLCArgs.push_back ("-o");
197   LLCArgs.push_back (OutputAsmFile.c_str()); // Output to the Asm file
198   LLCArgs.push_back ("-f");                  // Overwrite as necessary...
199   LLCArgs.push_back (Bitcode.c_str());      // This is the input bitcode
200   LLCArgs.push_back (0);
201
202   std::cout << "<llc>" << std::flush;
203   DEBUG(std::cerr << "\nAbout to run:\t";
204         for (unsigned i=0, e = LLCArgs.size()-1; i != e; ++i)
205           std::cerr << " " << LLCArgs[i];
206         std::cerr << "\n";
207         );
208   if (RunProgramWithTimeout(sys::Path(LLCPath), &LLCArgs[0],
209                             sys::Path(), sys::Path(), sys::Path()))
210     ProcessFailure(sys::Path(LLCPath), &LLCArgs[0]);
211
212   return GCC::AsmFile;                              
213 }
214
215 void LLC::compileProgram(const std::string &Bitcode) {
216   sys::Path OutputAsmFile;
217   OutputCode(Bitcode, OutputAsmFile);
218   OutputAsmFile.eraseFromDisk();
219 }
220
221 int LLC::ExecuteProgram(const std::string &Bitcode,
222                         const std::vector<std::string> &Args,
223                         const std::string &InputFile,
224                         const std::string &OutputFile,
225                         const std::vector<std::string> &ArgsForGCC,
226                         const std::vector<std::string> &SharedLibs,
227                         unsigned Timeout,
228                         unsigned MemoryLimit) {
229
230   sys::Path OutputAsmFile;
231   OutputCode(Bitcode, OutputAsmFile);
232   FileRemover OutFileRemover(OutputAsmFile);
233
234   std::vector<std::string> GCCArgs(ArgsForGCC);
235   GCCArgs.insert(GCCArgs.end(),SharedLibs.begin(),SharedLibs.end());
236
237   // Assuming LLC worked, compile the result with GCC and run it.
238   return gcc->ExecuteProgram(OutputAsmFile.toString(), Args, GCC::AsmFile,
239                              InputFile, OutputFile, GCCArgs,
240                              Timeout, MemoryLimit);
241 }
242
243 /// createLLC - Try to find the LLC executable
244 ///
245 LLC *AbstractInterpreter::createLLC(const std::string &ProgramPath,
246                                     std::string &Message,
247                                     const std::vector<std::string> *Args) {
248   std::string LLCPath = FindExecutable("llc", ProgramPath).toString();
249   if (LLCPath.empty()) {
250     Message = "Cannot find `llc' in executable directory or PATH!\n";
251     return 0;
252   }
253
254   Message = "Found llc: " + LLCPath + "\n";
255   GCC *gcc = GCC::create(ProgramPath, Message);
256   if (!gcc) {
257     std::cerr << Message << "\n";
258     exit(1);
259   }
260   return new LLC(LLCPath, gcc, Args);
261 }
262
263 //===---------------------------------------------------------------------===//
264 // JIT Implementation of AbstractIntepreter interface
265 //
266 namespace {
267   class JIT : public AbstractInterpreter {
268     std::string LLIPath;          // The path to the LLI executable
269     std::vector<std::string> ToolArgs; // Args to pass to LLI
270   public:
271     JIT(const std::string &Path, const std::vector<std::string> *Args)
272       : LLIPath(Path) {
273       ToolArgs.clear ();
274       if (Args) { ToolArgs = *Args; }
275     }
276
277     virtual int ExecuteProgram(const std::string &Bitcode,
278                                const std::vector<std::string> &Args,
279                                const std::string &InputFile,
280                                const std::string &OutputFile,
281                                const std::vector<std::string> &GCCArgs =
282                                  std::vector<std::string>(),
283                                const std::vector<std::string> &SharedLibs =
284                                  std::vector<std::string>(), 
285                                unsigned Timeout =0,
286                                unsigned MemoryLimit =0);
287   };
288 }
289
290 int JIT::ExecuteProgram(const std::string &Bitcode,
291                         const std::vector<std::string> &Args,
292                         const std::string &InputFile,
293                         const std::string &OutputFile,
294                         const std::vector<std::string> &GCCArgs,
295                         const std::vector<std::string> &SharedLibs,
296                         unsigned Timeout,
297                         unsigned MemoryLimit) {
298   if (!GCCArgs.empty())
299     throw ToolExecutionError("JIT does not support GCC Arguments.");
300   // Construct a vector of parameters, incorporating those from the command-line
301   std::vector<const char*> JITArgs;
302   JITArgs.push_back(LLIPath.c_str());
303   JITArgs.push_back("-force-interpreter=false");
304
305   // Add any extra LLI args.
306   for (unsigned i = 0, e = ToolArgs.size(); i != e; ++i)
307     JITArgs.push_back(ToolArgs[i].c_str());
308
309   for (unsigned i = 0, e = SharedLibs.size(); i != e; ++i) {
310     JITArgs.push_back("-load");
311     JITArgs.push_back(SharedLibs[i].c_str());
312   }
313   JITArgs.push_back(Bitcode.c_str());
314   // Add optional parameters to the running program from Argv
315   for (unsigned i=0, e = Args.size(); i != e; ++i)
316     JITArgs.push_back(Args[i].c_str());
317   JITArgs.push_back(0);
318
319   std::cout << "<jit>" << std::flush;
320   DEBUG(std::cerr << "\nAbout to run:\t";
321         for (unsigned i=0, e = JITArgs.size()-1; i != e; ++i)
322           std::cerr << " " << JITArgs[i];
323         std::cerr << "\n";
324         );
325   DEBUG(std::cerr << "\nSending output to " << OutputFile << "\n");
326   return RunProgramWithTimeout(sys::Path(LLIPath), &JITArgs[0],
327       sys::Path(InputFile), sys::Path(OutputFile), sys::Path(OutputFile),
328       Timeout, MemoryLimit);
329 }
330
331 /// createJIT - Try to find the LLI executable
332 ///
333 AbstractInterpreter *AbstractInterpreter::createJIT(const std::string &ProgPath,
334                    std::string &Message, const std::vector<std::string> *Args) {
335   std::string LLIPath = FindExecutable("lli", ProgPath).toString();
336   if (!LLIPath.empty()) {
337     Message = "Found lli: " + LLIPath + "\n";
338     return new JIT(LLIPath, Args);
339   }
340
341   Message = "Cannot find `lli' in executable directory or PATH!\n";
342   return 0;
343 }
344
345 GCC::FileType CBE::OutputCode(const std::string &Bitcode,
346                               sys::Path &OutputCFile) {
347   sys::Path uniqueFile(Bitcode+".cbe.c");
348   std::string ErrMsg;
349   if (uniqueFile.makeUnique(true, &ErrMsg)) {
350     std::cerr << "Error making unique filename: " << ErrMsg << "\n";
351     exit(1);
352   }
353   OutputCFile = uniqueFile;
354   std::vector<const char *> LLCArgs;
355   LLCArgs.push_back (LLCPath.c_str());
356
357   // Add any extra LLC args.
358   for (unsigned i = 0, e = ToolArgs.size(); i != e; ++i)
359     LLCArgs.push_back(ToolArgs[i].c_str());
360
361   LLCArgs.push_back ("-o");
362   LLCArgs.push_back (OutputCFile.c_str());   // Output to the C file
363   LLCArgs.push_back ("-march=c");            // Output C language
364   LLCArgs.push_back ("-f");                  // Overwrite as necessary...
365   LLCArgs.push_back (Bitcode.c_str());      // This is the input bitcode
366   LLCArgs.push_back (0);
367
368   std::cout << "<cbe>" << std::flush;
369   DEBUG(std::cerr << "\nAbout to run:\t";
370         for (unsigned i=0, e = LLCArgs.size()-1; i != e; ++i)
371           std::cerr << " " << LLCArgs[i];
372         std::cerr << "\n";
373         );
374   if (RunProgramWithTimeout(LLCPath, &LLCArgs[0], sys::Path(), sys::Path(),
375                             sys::Path()))
376     ProcessFailure(LLCPath, &LLCArgs[0]);
377   return GCC::CFile;
378 }
379
380 void CBE::compileProgram(const std::string &Bitcode) {
381   sys::Path OutputCFile;
382   OutputCode(Bitcode, OutputCFile);
383   OutputCFile.eraseFromDisk();
384 }
385
386 int CBE::ExecuteProgram(const std::string &Bitcode,
387                         const std::vector<std::string> &Args,
388                         const std::string &InputFile,
389                         const std::string &OutputFile,
390                         const std::vector<std::string> &ArgsForGCC,
391                         const std::vector<std::string> &SharedLibs,
392                         unsigned Timeout,
393                         unsigned MemoryLimit) {
394   sys::Path OutputCFile;
395   OutputCode(Bitcode, OutputCFile);
396
397   FileRemover CFileRemove(OutputCFile);
398
399   std::vector<std::string> GCCArgs(ArgsForGCC);
400   GCCArgs.insert(GCCArgs.end(),SharedLibs.begin(),SharedLibs.end());
401   return gcc->ExecuteProgram(OutputCFile.toString(), Args, GCC::CFile,
402                              InputFile, OutputFile, GCCArgs,
403                              Timeout, MemoryLimit);
404 }
405
406 /// createCBE - Try to find the 'llc' executable
407 ///
408 CBE *AbstractInterpreter::createCBE(const std::string &ProgramPath,
409                                     std::string &Message,
410                                     const std::vector<std::string> *Args) {
411   sys::Path LLCPath = FindExecutable("llc", ProgramPath);
412   if (LLCPath.isEmpty()) {
413     Message =
414       "Cannot find `llc' in executable directory or PATH!\n";
415     return 0;
416   }
417
418   Message = "Found llc: " + LLCPath.toString() + "\n";
419   GCC *gcc = GCC::create(ProgramPath, Message);
420   if (!gcc) {
421     std::cerr << Message << "\n";
422     exit(1);
423   }
424   return new CBE(LLCPath, gcc, Args);
425 }
426
427 //===---------------------------------------------------------------------===//
428 // GCC abstraction
429 //
430 int GCC::ExecuteProgram(const std::string &ProgramFile,
431                         const std::vector<std::string> &Args,
432                         FileType fileType,
433                         const std::string &InputFile,
434                         const std::string &OutputFile,
435                         const std::vector<std::string> &ArgsForGCC,
436                         unsigned Timeout,
437                         unsigned MemoryLimit) {
438   std::vector<const char*> GCCArgs;
439
440   GCCArgs.push_back(GCCPath.c_str());
441
442   // Specify -x explicitly in case the extension is wonky
443   GCCArgs.push_back("-x");
444   if (fileType == CFile) {
445     GCCArgs.push_back("c");
446     GCCArgs.push_back("-fno-strict-aliasing");
447   } else {
448     GCCArgs.push_back("assembler");
449 #ifdef __APPLE__
450     GCCArgs.push_back("-force_cpusubtype_ALL");
451 #endif
452   }
453   GCCArgs.push_back(ProgramFile.c_str());  // Specify the input filename...
454   GCCArgs.push_back("-x");
455   GCCArgs.push_back("none");
456   GCCArgs.push_back("-o");
457   sys::Path OutputBinary (ProgramFile+".gcc.exe");
458   std::string ErrMsg;
459   if (OutputBinary.makeUnique(true, &ErrMsg)) {
460     std::cerr << "Error making unique filename: " << ErrMsg << "\n";
461     exit(1);
462   }
463   GCCArgs.push_back(OutputBinary.c_str()); // Output to the right file...
464
465   // Add any arguments intended for GCC. We locate them here because this is
466   // most likely -L and -l options that need to come before other libraries but
467   // after the source. Other options won't be sensitive to placement on the
468   // command line, so this should be safe.
469   for (unsigned i = 0, e = ArgsForGCC.size(); i != e; ++i)
470     GCCArgs.push_back(ArgsForGCC[i].c_str());
471
472   GCCArgs.push_back("-lm");                // Hard-code the math library...
473   GCCArgs.push_back("-O2");                // Optimize the program a bit...
474 #if defined (HAVE_LINK_R)
475   GCCArgs.push_back("-Wl,-R.");            // Search this dir for .so files
476 #endif
477 #ifdef __sparc__
478   GCCArgs.push_back("-mcpu=v9");
479 #endif
480   GCCArgs.push_back(0);                    // NULL terminator
481
482   std::cout << "<gcc>" << std::flush;
483   DEBUG(std::cerr << "\nAbout to run:\t";
484         for (unsigned i=0, e = GCCArgs.size()-1; i != e; ++i)
485           std::cerr << " " << GCCArgs[i];
486         std::cerr << "\n";
487         );
488   if (RunProgramWithTimeout(GCCPath, &GCCArgs[0], sys::Path(), sys::Path(),
489         sys::Path())) {
490     ProcessFailure(GCCPath, &GCCArgs[0]);
491     exit(1);
492   }
493
494   std::vector<const char*> ProgramArgs;
495
496   if (RSHPath.isEmpty())
497     ProgramArgs.push_back(OutputBinary.c_str());
498   else {
499     ProgramArgs.push_back(RSHPath.c_str());
500     ProgramArgs.push_back(RSHHost.c_str());
501     ProgramArgs.push_back("-l");
502     ProgramArgs.push_back(RSHUser.c_str());
503
504     char* env_pwd = getenv("PWD");
505     std::string Exec = "cd ";
506     Exec += env_pwd;
507     Exec += "; ./";
508     Exec += OutputBinary.c_str();
509     ProgramArgs.push_back(Exec.c_str());
510   }
511
512   // Add optional parameters to the running program from Argv
513   for (unsigned i=0, e = Args.size(); i != e; ++i)
514     ProgramArgs.push_back(Args[i].c_str());
515   ProgramArgs.push_back(0);                // NULL terminator
516
517   // Now that we have a binary, run it!
518   std::cout << "<program>" << std::flush;
519   DEBUG(std::cerr << "\nAbout to run:\t";
520         for (unsigned i=0, e = ProgramArgs.size()-1; i != e; ++i)
521           std::cerr << " " << ProgramArgs[i];
522         std::cerr << "\n";
523         );
524
525   FileRemover OutputBinaryRemover(OutputBinary);
526
527   if (RSHPath.isEmpty())
528     return RunProgramWithTimeout(OutputBinary, &ProgramArgs[0],
529         sys::Path(InputFile), sys::Path(OutputFile), sys::Path(OutputFile),
530         Timeout, MemoryLimit);
531   else
532     return RunProgramWithTimeout(sys::Path(RSHPath), &ProgramArgs[0],
533         sys::Path(InputFile), sys::Path(OutputFile), sys::Path(OutputFile),
534         Timeout, MemoryLimit);
535 }
536
537 int GCC::MakeSharedObject(const std::string &InputFile, FileType fileType,
538                           std::string &OutputFile,
539                           const std::vector<std::string> &ArgsForGCC) {
540   sys::Path uniqueFilename(InputFile+LTDL_SHLIB_EXT);
541   std::string ErrMsg;
542   if (uniqueFilename.makeUnique(true, &ErrMsg)) {
543     std::cerr << "Error making unique filename: " << ErrMsg << "\n";
544     exit(1);
545   }
546   OutputFile = uniqueFilename.toString();
547
548   std::vector<const char*> GCCArgs;
549   
550   GCCArgs.push_back(GCCPath.c_str());
551   
552   
553   // Compile the C/asm file into a shared object
554   GCCArgs.push_back("-x");
555   GCCArgs.push_back(fileType == AsmFile ? "assembler" : "c");
556   GCCArgs.push_back("-fno-strict-aliasing");
557   GCCArgs.push_back(InputFile.c_str());   // Specify the input filename.
558   GCCArgs.push_back("-x");
559   GCCArgs.push_back("none");
560 #if defined(sparc) || defined(__sparc__) || defined(__sparcv9)
561   GCCArgs.push_back("-G");       // Compile a shared library, `-G' for Sparc
562 #elif defined(__APPLE__)
563   // link all source files into a single module in data segment, rather than
564   // generating blocks. dynamic_lookup requires that you set 
565   // MACOSX_DEPLOYMENT_TARGET=10.3 in your env.  FIXME: it would be better for
566   // bugpoint to just pass that in the environment of GCC.
567   GCCArgs.push_back("-single_module");
568   GCCArgs.push_back("-dynamiclib");   // `-dynamiclib' for MacOS X/PowerPC
569   GCCArgs.push_back("-undefined");
570   GCCArgs.push_back("dynamic_lookup");
571 #else
572   GCCArgs.push_back("-shared");  // `-shared' for Linux/X86, maybe others
573 #endif
574
575 #if defined(__ia64__) || defined(__alpha__)
576   GCCArgs.push_back("-fPIC");   // Requires shared objs to contain PIC
577 #endif
578 #ifdef __sparc__
579   GCCArgs.push_back("-mcpu=v9");
580 #endif
581   GCCArgs.push_back("-o");
582   GCCArgs.push_back(OutputFile.c_str()); // Output to the right filename.
583   GCCArgs.push_back("-O2");              // Optimize the program a bit.
584
585   
586   
587   // Add any arguments intended for GCC. We locate them here because this is
588   // most likely -L and -l options that need to come before other libraries but
589   // after the source. Other options won't be sensitive to placement on the
590   // command line, so this should be safe.
591   for (unsigned i = 0, e = ArgsForGCC.size(); i != e; ++i)
592     GCCArgs.push_back(ArgsForGCC[i].c_str());
593   GCCArgs.push_back(0);                    // NULL terminator
594
595   
596
597   std::cout << "<gcc>" << std::flush;
598   DEBUG(std::cerr << "\nAbout to run:\t";
599         for (unsigned i=0, e = GCCArgs.size()-1; i != e; ++i)
600           std::cerr << " " << GCCArgs[i];
601         std::cerr << "\n";
602         );
603   if (RunProgramWithTimeout(GCCPath, &GCCArgs[0], sys::Path(), sys::Path(),
604                             sys::Path())) {
605     ProcessFailure(GCCPath, &GCCArgs[0]);
606     return 1;
607   }
608   return 0;
609 }
610
611 /// create - Try to find the `gcc' executable
612 ///
613 GCC *GCC::create(const std::string &ProgramPath, std::string &Message) {
614   sys::Path GCCPath = FindExecutable("gcc", ProgramPath);
615   if (GCCPath.isEmpty()) {
616     Message = "Cannot find `gcc' in executable directory or PATH!\n";
617     return 0;
618   }
619
620   sys::Path RSHPath;
621   if (!RSHHost.empty())
622     RSHPath = FindExecutable("rsh", ProgramPath);
623
624   Message = "Found gcc: " + GCCPath.toString() + "\n";
625   return new GCC(GCCPath, RSHPath);
626 }