Re: Bugs using -fPIC on linux (i86 RedHat 5.0)?

[Jeffrey A Law <law at cygnus dot com>]

  In message <19971229091404.35828@dot.cygnus.com>you write:
  > On Mon, Dec 29, 1997 at 03:22:09PM +0100, Marius Kjeldahl wrote:
  > > (I do not know _why_ it runs without -fPIC - maybe it simply
  > > does not gain me the real benefit of a shared library, meaning several
  > > applications will load the library into their own private memory space
  > > - just guessing here).
  > 
  > A pretty good guess -- the pages start out shared and then get dirtied
  > by the relocations that are applied, which makes them not shared.  The
  > fact that it does work has its uses though.
  > 
  > > In looking at the temporary assembler file, the lines it objects to is:
  > > 
  > > 	call @PLT
  > 
  > This is a compiler bug, as the target symbol for the call is missing.
  > Can you give us the preprocessed file that generates this problem?
Well, on the x86, I don't see how you can get @PLT without a 
function name -- unless the compiler mis-compiled itself or we have
a SYMBOL_REF with a null name.  From i386.c:

    case SYMBOL_REF:
    case LABEL_REF:
      if (GET_CODE (x) == SYMBOL_REF)
        assemble_name (file, XSTR (x, 0));
      else
        {
          ASM_GENERATE_INTERNAL_LABEL (buf, "L",
                                       CODE_LABEL_NUMBER (XEXP (x, 0)));
          assemble_name (asm_out_file, buf);
        }

      if (GET_CODE (x) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (x))
        fprintf (file, "@GOTOFF(%%ebx)");
      else if (code == 'P')
        fprintf (file, "@PLT");