Date: Mon, 27 Nov 2000 09:41:39 +0100
From: Werner Almesberger <[EMAIL PROTECTED]>
egcs-2.91.66 indeed doesn't seem to make this optimization on i386.
(Maybe the pointer increment or pointer offset solution would
actually be slower - didn't check.) But I'm not sure if this is
also true for other versions/architectures, or other code
constructs.
There is no guarentee that contiguous data or bss section members
will appear contiguous and in the same order, in the final object.
In fact, a specific optimization done on MIPS and other platforms is
to place all data members under a certain size in a special
".small.data" section. So for example:
static int a;
static struct foo b;
static int b;
Would not place 'b' at "&a + sizeof(a) + sizeof(b)"
Also I believe linkers are allowed to arbitrarily reorder members in
the data and bss sections. I could be wrong on this one though.
Later,
David S. Miller
[EMAIL PROTECTED]
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