Re: addr2line and the name of the executable

[Mohan Embar <gnustuff at thisiscool dot com>]

>Would you be willing to let me get my feet wet by trying to code
>this up according to Andrew's and your specifications?

Hi People,
Here's what I came up with: I don't know if I'm on to something
or delusional (probably the latter). This isn't in diff
format because my build environment is kind of messed up right
now and I primarily want to get feedback on this approach. Please
indulge a bit of verbosity here because I'm new at this.

The motivation: allow for a a generic, yet platform-specific means
of determining the executable name of the current process. This might
also allow certain embedded targets to specify something other than
[Embedded App].

I've coded this and it works, but I'm worried that I might be way
off the mark here. Also addr2line doesn't seem to care for the absolute
path with backslashes on Win32 and stack traces don't work - haven't had
time to look into this.

First, I added this AC_DEFINE to configure.in

     case $host in
     *-linux*)
       AC_DEFINE(HAVE_PROC_SELF_EXE)
       ;;
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>     
     *mingw*)
       # Has a platform-specific mechanism for
       # for retrieving the name of the executable.
       AC_DEFINE(HAVE_PLATFORM_GETEXENAME)
       ;;
     esac
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

I also added the corresponding line to acconfig.h:

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
/* Define if you have a platform-specific _Jv_GetPlatformExecutableName */
#undef HAVE_PLATFORM_GETEXENAME
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

I reran autoconf and autoheader.

In prims.cc, we have:

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
#ifdef HAVE_PLATFORM_GETEXENAME
extern "C" void _Jv_GetPlatformExecutableName(char* buf, int size);
  // this platform has a specific way of retrieving our executable
  // name which overrides other mechanisms (such as assuming
  // argv[0], etc.)
#endif
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Later in prims.cc, we add one more test in _Jv_RunMain:

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
#if defined(DISABLE_MAIN_ARGS)
  _Jv_ThisExecutable ("[Embedded App]");
#elif defined(HAVE_PLATFORM_GETEXENAME)
  char exec_name[300];
  _Jv_GetPlatformExecutableName(exec_name, sizeof(exec_name));
  _Jv_ThisExecutable (exec_name);
#elif defined(HAVE_PROC_SELF_EXE)
  char exec_name[20];
  sprintf (exec_name, "/proc/%d/exe", getpid ());
  _Jv_ThisExecutable (exec_name);
#else
  _Jv_ThisExecutable (argv[0]);
#endif /* DISABLE_MAIN_ARGS, HAVE_PLATFORM_GETEXENAME, HAVE_PROC_SELF_EXE */
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Finally, we provide our platform-specific implementation
in win32.cc:

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
extern "C" void _Jv_GetPlatformExecutableName(char* buf, int size)
{
  GetModuleFileName(NULL, buf, size);
}
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

In essence, prims.cc declares a common interface for a platform-specific
mechanism of obtaining the name of the current process.

-- Mohan
http://www.thisiscool.com/
http://www.animalsong.org/