Re: preprocessor/5886: IA64 ABI predefined symbol missing

[Zack Weinberg <zack at codesourcery dot com>]

The following reply was made to PR preprocessor/5886; it has been noted by GNATS.

From: Zack Weinberg <zack@codesourcery.com>
To: nick@usenix.org
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: preprocessor/5886: IA64 ABI predefined symbol missing
Date: Fri, 8 Mar 2002 10:58:10 -0800

 > 	Section 7.2 of the Intel (r) Itanium (tm) processor specific
 > Application Binary Interface (see
 > http://developer.intel.com/design/itanium/downloads/245370.htm)
 > states that the symbol _LP64 should be predefined for IA64 target
 > with LP64 architecture.  The symbol __LP64__ is defined, but not
 > _LP64.
 
 There's no problem adding this; _LP64 is in the implementation name
 space.  You'll need to get it approved by an ia64 arch maintainer,
 though.
 
 >  Also, there should be an assertion for the default endian case,
 > -Aendian(little), in the preprocessor initialization. If it is
 > possible to produce big-endian Itanium code (and I haven't figured
 > out yet if you can), then this assertion should track the compiler
 > flag to produce bigendian code. Otherwise, it can be handled by the
 > patch attached.
 
 Preprocessor assertions are deprecated.  We will add them to GCC's
 configuration files only when they are necessary for compatibility
 with other compilers.  Please remove all mention of assertions from
 standards documents you control, and encourage other standards
 developers to do the same.
 
 The switches you are looking for are -mbig-endian and
 -mlittle-endian.  See ia64.h.
 
 >  The fix below applies only to linux systems, and not to all IA64
 > systems. Since this symbol and assertion are required by the Intel
 > ABI, it might be better to move them to a higher level
 > file.
 
 Yes, this stuff belongs in ia64.h.
 
 zw