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Re: Group static constructors and destructors in specific subsections, take 2
On 11/24/2010 08:09 AM, Jan Hubicka wrote:
> Hi,
> as Jakub, Tromey and Jason patiently explained to me, the cold_text_section
> code in dwarf2out is just optimizations. Functions in separate sections are
> handled elsewhere. So I take back my claims about dwarf2out being broken in
> partitioning and attaching the updated patch. The only difference is in
> dwarf2out_begin_function that waits for first function in text section (that
> consequently have standard cold sectoin) and initialize vars correspondingly.
>
> Bootstrapped/regtested x86_64-linux, OK?
>
> Honza
>
> * dwarf2out.c (dwarf2out_begin_function): Initialize cold_text_section
> and emit cold_text_section_label.
> (dwarf2out_init): Don't do that there.
> (dwarf2out_finish): Emit end label only when cold_text_section is
> initialized.
> Index: dwarf2out.c
> ===================================================================
> *** dwarf2out.c (revision 167086)
> --- dwarf2out.c (working copy)
> *************** dwarf2out_begin_function (tree fun)
> *** 21676,21681 ****
> --- 21676,21689 ----
> {
> if (function_section (fun) != text_section)
> have_multiple_function_sections = true;
> + else if (flag_reorder_blocks_and_partition && !cold_text_section)
> + {
> + gcc_assert (current_function_decl == fun);
> + cold_text_section = unlikely_text_section ();
> + switch_to_section (cold_text_section);
> + ASM_OUTPUT_LABEL (asm_out_file, cold_text_section_label);
> + switch_to_section (current_function_section ());
> + }
Is there a quick way to determine if the function will ever go into the
cold_text_section? It would be nice if a given translation unit is
entirely non-cold that we never switch into the cold_text_section to
create that label.
If there is no way for that atm, then the patch is ok as-is. It's
clearly an improvement over the current state of affairs.
r~