Lazy allocation of DECL_ASSEMBLER_NAME

[Mark Mitchell <mark at codesourcery dot com>]

Jan --

I believe that your cgraph stuff has caused us to be much less lazy
about allocating DECL_ASSEMBLER_NAME than we used to be.  

A while back, I changed DECL_ASSEMBLER_NAME to allocate lazily because
I observed that we were allocating a ton of space for mangled names
for entities that were never omitted.  Now, it looks like cgraph has
gone back to using DECL_ASSEMBLER_NAME unconditionally.

It is basically a bug for any part of the code in the compiler to use
DECL_ASSEMBLER_NAME other than the routines that actually emity
assembly code.  It should be possible to assign DECL_ASSEMBLER_NAMEs
only after the entire translation unit has been parsed, analyzed, and
it has been decided what functions and variables need to be omitted to
the object file.  All other uses are either wrong, or hacks that
should be replaced with a cleaner mechanism.

To check for whether two declarations are the same, just compare their
addresses.  If a front end creates two FUNCTION_DECLs or VAR_DECLs
that happen to have the same DECL_ASSEMBLER_NAME that's either a bug
or an intentional trick on the part of the front end: by the time
things get to the middle end there should be only one DECL for each
declared entity.

Would you please see if you can fix this problem -- after fixing some
of the wrong-code/ICE problems in 3.4?

Thanks,

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com