gclcvs

[Camm Maguire <camm@enhanced.com>]

Greetings!  gcl uses a homemade address lookup table for functions it
directly writes into C sources files to be compiled and loaded into
the running image.  The code looks like this:

typedef struct {
  const char *n;
  unsigned long ad;
} Plt;

#define MY_PLT(a_) {#a_,(unsigned long)(void *)a_}

static Plt mplt[]={
	/* This is an attempt to at least capture the addresses to
	   which the compiler directly refers in C code. (Some symbols
	   are not explicitly mentioned in the C source but are
	   generated by gcc, usually in a platform specific way). At
	   the time of this writing, these symbols alone are
	   sufficient for compiling maxima,acl2,and axiom on x86.
	   This table is not (currently at least) consulted in
	   actuality -- the mere mention of the symbols here (at
	   present) ensures that the symbols are assigned values by
	   the linker, which are used preferentially to these values
	   in sfasli.c.  FIXME -- this should be made synchronous with
	   compiler changes; sort the list automatically.  SORT THIS
	   LIST BY HAND FOR THE TIME BEING. */
#ifndef _WIN32
#  include "plt.h"
#endif    
};

=============================================================================
plt.h:
=============================================================================
MY_PLT(_IO_getc),
MY_PLT(_IO_putc),
MY_PLT(_mcount),
MY_PLT(_setjmp),
MY_PLT(acos),
MY_PLT(acosh),
MY_PLT(asin),
MY_PLT(asinh),
MY_PLT(atan),
MY_PLT(atanh),
MY_PLT(bzero),
MY_PLT(cos),
MY_PLT(cosh),
MY_PLT(exp),
MY_PLT(fdopen),
MY_PLT(feof),
MY_PLT(log),
MY_PLT(logl),
MY_PLT(memset),
MY_PLT(read),
MY_PLT(sin),
MY_PLT(sinh),
MY_PLT(sqrt),
MY_PLT(tan),
MY_PLT(tanh),
MY_PLT(write)
=============================================================================

This has worked for quite a while, but with the latest gcc (4.1) on
mips, I cannot avoid having the address of the gcc builtin picked up
here, no matter if I use -fno-builtin or anything else, it seems.  And
for some other reason, relocating a loaded object address to the
address of the builtin function does not return properly -- I'm
guessing there are non-standard call sematics here.

Any idea of a workaround?  That is, short of putting in my own
trampolines for each function:

static double cos1(double x) {
  return cos(x);
}
#undef cos
#define cos cos1

static Plt mplt[]={
...

Take care,
-- 
Camm Maguire			     			camm@enhanced.com
==========================================================================
"The earth is but one country, and mankind its citizens."  --  Baha'u'llah