llvm-stub.c revision 4c6d124efa433347c7280d4a075d954bd0231a78 
1/*===- llvm-stub.c - Stub executable to run llvm bytecode files -----------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This tool is used by the gccld program to enable transparent execution of
11// bytecode files by the user.  Specifically, gccld outputs two files when asked
12// to compile a <program> file:
13//    1. It outputs the LLVM bytecode 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 doesn't 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#include "Config/unistd.h"  /* provides definition of execve */
27
28int main(int argc, char** argv) {
29  const char *Interp = getenv("LLVMINTERP");
30  const char **Args;
31  if (Interp == 0) Interp = "lli";
32
33  /* Set up the command line options to pass to the JIT. */
34  Args = (const char**)malloc(sizeof(char*) * (argc+2));
35  /* argv[0] is the JIT */
36  Args[0] = Interp;
37  /* argv[1] is argv[0] + ".bc". */
38  Args[1] = strcat(strcpy((char*)malloc(strlen(argv[0])+4), argv[0]), ".bc");
39
40  /* The rest of the args are as before. */
41  memcpy(Args+2, argv+1, sizeof(char*)*argc);
42
43  /* Run the JIT. */
44  execvp(Interp, (char *const*)Args);
45
46  /* if _execv returns, the JIT could not be started. */
47  fprintf(stderr, "Could not execute the LLVM JIT.  Either add 'lli' to your"
48          " path, or set the\ninterpreter you want to use in the LLVMINTERP "
49          "environment variable.\n");
50  return 1;
51}
52