Initial checkin of a stub executable that can be used by gccld to forward to

bytecode files on systems that don't support #!/bin/sh natively (ie, win32).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13937 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-stub/Makefile

@@ -0,0 +1,13 @@
+##===- tools/llvm-stub/Makefile ----------------------------*- Makefile -*-===##
+# 
+#                     The LLVM Compiler Infrastructure
+#
+# This file was developed by the LLVM research group and is distributed under
+# the University of Illinois Open Source License. See LICENSE.TXT for details.
+# 
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../..
+TOOLNAME = llvm-stub
+include $(LEVEL)/Makefile.common
+

tools/llvm-stub/llvm-stub.c

@@ -0,0 +1,51 @@
+/*===- llvm-stub.c - Stub executable to run llvm bytecode files -----------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This tool is used by the gccld program to enable transparent execution of
+// bytecode files by the user.  Specifically, gccld outputs two files when asked
+// to compile a <program> file:
+//    1. It outputs the LLVM bytecode file to <program>.bc
+//    2. It outputs a stub executable that runs lli on <program>.bc
+//
+// This allows the end user to just say ./<program> and have the JIT executed
+// automatically.  On unix, the stub executable emitted is actually a bourne
+// shell script that does the forwarding.  Windows doesn't not like #!/bin/sh
+// programs in .exe files, so we make it an actual program, defined here.
+//
+//===----------------------------------------------------------------------===*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "Config/unistd.h"  /* provides definition of execve */
+
+int main(int argc, char** argv) {
+  const char *Interp = getenv("LLVMINTERP");
+  const char **Args;
+  if (Interp == 0) Interp = "lli";
+
+  /* Set up the command line options to pass to the JIT. */
+  Args = (const char**)malloc(sizeof(char*) * (argc+2));
+  /* argv[0] is the JIT */
+  Args[0] = Interp;
+  /* argv[1] is argv[0] + ".bc". */
+  Args[1] = strcat(strcpy((char*)malloc(strlen(argv[0])+4), argv[0]), ".bc");
+
+  /* The rest of the args are as before. */
+  memcpy(Args+2, argv+1, sizeof(char*)*argc);
+
+  /* Run the JIT. */
+  execvp(Interp, (char *const*)Args);
+
+  /* if _execv returns, the JIT could not be started. */
+  fprintf(stderr, "Could not execute the LLVM JIT.  Either add 'lli' to your"
+          " path, or set the\ninterpreter you want to use in the LLVMINTERP "
+          "environment variable.\n");
+  return 1;
+}