On Wed, 19 Jul 2017, Jan Hubicka wrote:
> > Did you see the inline comments?
>
> I missed them, sorry :)
> This is updated patch I am testing.
Ok with adding
+ maybe_add_nop_after_section_switch ();
in pass_convert_to_eh_region_ranges::execute instead.
Richard.
> Index: except.c
> ===================================================================
> --- except.c (revision 250312)
> +++ except.c (working copy)
> @@ -2444,6 +2444,61 @@ emit_note_eh_region_end (rtx_insn *insn)
> return emit_note_after (NOTE_INSN_EH_REGION_END, insn);
> }
>
> +/* Add NOP after NOTE_INSN_SWITCH_TEXT_SECTIONS when the cold section starts
> + with landing pad.
> + With landing pad being at offset 0 from the start label of the section
> + we would miss EH delivery because 0 is special and means no landing pad.
> */
> +
> +bool
> +maybe_add_nop_after_section_switch (void)
> +{
> + if (!crtl->uses_eh_lsda
> + || !crtl->eh.call_site_record_v[1])
> + return false;
> + int n = vec_safe_length (crtl->eh.call_site_record_v[1]);
> + hash_set<rtx_insn *> visited;
> +
> + for (int i = 0; i < n; ++i)
> + {
> + struct call_site_record_d *cs
> + = (*crtl->eh.call_site_record_v[1])[i];
> + if (cs->landing_pad)
> + {
> + rtx_insn *insn = as_a <rtx_insn *> (cs->landing_pad);
> + while (true)
> + {
> + /* Landing pads have LABEL_PRESERVE_P flag set. This check make
> + sure that we do not walk past landing pad visited earlier
> + which would result in possible quadratic behaviour. */
> + if (LABEL_P (insn) && LABEL_PRESERVE_P (insn)
> + && visited.add (insn))
> + break;
> +
> + /* Conservatively assume that ASM insn may be empty. We have
> + now way to tell what they contain. */
> + if (active_insn_p (insn)
> + && GET_CODE (PATTERN (insn)) != ASM_INPUT
> + && GET_CODE (PATTERN (insn)) != ASM_OPERANDS)
> + break;
> +
> + /* If we reached the start of hot section, then NOP will be
> + needed. */
> + if (GET_CODE (insn) == NOTE
> + && NOTE_KIND (insn) == NOTE_INSN_SWITCH_TEXT_SECTIONS)
> + {
> + emit_insn_after (gen_nop (), insn);
> + break;
> + }
> +
> + /* We visit only labels from cold section. We should never hit
> + begining of the insn stream here. */
> + insn = PREV_INSN (insn);
> + }
> + }
> + }
> + return false;
> +}
> +
> /* Turn REG_EH_REGION notes back into NOTE_INSN_EH_REGION notes.
> The new note numbers will not refer to region numbers, but
> instead to call site entries. */
> @@ -2466,6 +2521,8 @@ convert_to_eh_region_ranges (void)
> rtx_insn *last_no_action_insn_before_switch = NULL;
> int saved_call_site_base = call_site_base;
>
> + maybe_add_nop_after_section_switch ();
> +
> vec_alloc (crtl->eh.action_record_data, 64);
>
> for (iter = get_insns (); iter ; iter = NEXT_INSN (iter))
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
