On 22.01.2007 [17:08:34 -0600], Adam Litke wrote:
> The current extracopysize detection algorithm does not include weak
> objects in the copy window. These are symbols marked with 'W' and 'V'
> in nm output. These can in fact be initialized global variables (just
> like STB_GLOBAL symbols) and should be included in the extracopy window.
>
> The following patch adds STB_WEAK symbols to the extracopy window.
> Since the if statement is getting a bit large and out of hand, move the
> logic out of the function and into its own macro "keep_symbol".
>
> This patch resolves an eon (speccpu2000 benchmark) failure.
>
> Signed-off-by: Adam Litke <[EMAIL PROTECTED]>
>
> diff --git a/elflink.c b/elflink.c
> index 6b260c9..9556dad 100644
> --- a/elflink.c
> +++ b/elflink.c
> @@ -464,6 +464,23 @@ static int find_numsyms(Elf_Sym *symtab,
> return ((void *)strtab - (void *)symtab) / sizeof(Elf_Sym);
> }
>
> +/*
> + * To reduce the size of the extra copy window, we can eliminate certain
> + * symbols based on information in the dynamic section. The following
> + * characteristics apply to symbols which may require copying:
> + * - Within the BSS
> + * - Global or Weak binding
> + * - Object type (variable)
> + * - Non-zero size (zero size means the symbol is just a marker with no data)
> + */
> +#define keep_symbol(s) \
> + ((((void *)s->st_value >= start_orig) && \
> + ((void *)s->st_value <= end_orig)) && \
> + ((ELF_ST_BIND(s->st_info) == STB_GLOBAL) || \
> + (ELF_ST_BIND(s->st_info) == STB_WEAK)) && \
> + (ELF_ST_TYPE(sym->st_info) == STT_OBJECT) && \
typo --^ ? Shouldn't that be s->st_info, not sym->st_info?
> + (s->st_size > 0))
You really should encapsulate every use of "s" with parentheses too, or
make it explicit that it can't be of a particular type (this is a common
problem in the kernel, for instance).
Would this be cleaner as a static inline function (would have also
caught the typo above)? That way, we also get type checking (admittedly
only one invocation and there probably won't be any more, but in case we
need to make this statement longer anytime in the future I'd rather it
were made a function now).
Something like
static inline int keep_symbol(Elf_Sym *s)
{
if (((void *)s->st_value >= start_orig) &&
((void *)s->st_value <= end_orig) &&
((ELF_ST_BIND(s->st_info) == STB_GLOBAL) ||
(ELF_ST_BIND(s->st_info) == STB_WEAK)) &&
(ELF_ST_TYPE(s->st_info) == STT_OBJECT) &&
(s->st_size > 0)) {
return 1;
else
return 0;
}
?
Thanks,
Nish
--
Nishanth Aravamudan <[EMAIL PROTECTED]>
IBM Linux Technology Center
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