tools/llvm-stub/llvm-stub.c

   1 /*===- llvm-stub.c - Stub executable to run llvm bitcode files ------------===//
   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 tool is used by the gccld program to enable transparent execution of
  11 // bitcode files by the user.  Specifically, gccld outputs two files when asked
  12 // to compile a <program> file:
  13 //    1. It outputs the LLVM bitcode file to <program>.bc
  14 //    2. It outputs a stub executable that runs lli on <program>.bc
  15 //
  16 // This allows the end user to just say ./<program> and have the JIT executed
  17 // automatically.  On unix, the stub executable emitted is actually a bourne
  18 // shell script that does the forwarding.  Windows does not like #!/bin/sh
  19 // programs in .exe files, so we make it an actual program, defined here.
  20 //
  21 //===----------------------------------------------------------------------===*/
  22
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 #include "llvm/Config/config.h"
  28
  29 #if defined(HAVE_UNISTD_H) && !defined(_MSC_VER)
  30 #include <unistd.h>
  31 #endif
  32
  33 #ifdef _WIN32
  34 #include <process.h>
  35 #include <io.h>
  36 #endif
  37
  38 int main(int argc, char** argv) {
  39   const char *Interp = getenv("LLVMINTERP");
  40   const char **Args;
  41   if (Interp == 0) Interp = "lli";
  42
  43   /* Set up the command line options to pass to the JIT. */
  44   Args = (const char**)malloc(sizeof(char*) * (argc+2));
  45   /* argv[0] is the JIT */
  46   Args[0] = Interp;
  47
  48 #ifdef LLVM_ON_WIN32
  49   {
  50     int len = strlen(argv[0]);
  51     if (len < 4 || strcmp(argv[0] + len - 4, ".exe") != 0) {
  52       /* .exe suffix is stripped off of argv[0] if the executable was run on the
  53        * command line without one. Put it back on.
  54        */
  55       argv[0] = strcat(strcpy((char*)malloc(len + 5), argv[0]), ".exe");
  56     }
  57   }
  58 #endif
  59
  60   /* argv[1] is argv[0] + ".bc". */
  61   Args[1] = strcat(strcpy((char*)malloc(strlen(argv[0])+4), argv[0]), ".bc");
  62
  63   /* The rest of the args are as before. */
  64   memcpy(Args+2, argv+1, sizeof(char*)*argc);
  65
  66   /* Run the JIT. */
  67   execvp(Interp, (char *const*)Args);
  68
  69   /* if _execv returns, the JIT could not be started. */
  70   fprintf(stderr, "Could not execute the LLVM JIT.  Either add 'lli' to your"
  71           " path, or set the\ninterpreter you want to use in the LLVMINTERP "
  72           "environment variable.\n");
  73   return 1;
  74 }