Laurent GUERBY <[EMAIL PROTECTED]> writes:
> On Fri, 2006-09-15 at 09:27 -0700, Ian Lance Taylor wrote:
> > I think Danny has a 75% implementation based on hashing the RTL for a
> > section and using that to select the COMDAT section signature. Or the
> > hashing can be done in the linker, but it still needs compiler help to
> > know when it is permissible.
>
> For code sections (I assume read-only), isn't the linker always able to
> merge identical ones? What can the compiler do better than the linker?
The linker can't merge just any identical code section, it can only
merge code sections where that is permitted. For example, consider:
int foo() { return 0; }
int bar() { return 0; }
int quux(int (*pfn)()) { return pfn == &foo; }
Compile with -ffunction-sections. If the linker merges sections, that
program will break.
I think that in general it would be safe to merge any equivalent
COMDAT code section, though.
Ian
