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* [gcc r14-1465] libstdc++: optimize EH phase 2
@ 2023-06-01 12:49 Jason Merrill
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From: Jason Merrill @ 2023-06-01 12:49 UTC (permalink / raw)
To: gcc-cvs, libstdc++-cvs
https://gcc.gnu.org/g:5d9c9119079ef14798b0a4fc771fd8d3905ec746
commit r14-1465-g5d9c9119079ef14798b0a4fc771fd8d3905ec746
Author: Jason Merrill <jason@redhat.com>
Date: Wed May 31 15:02:05 2023 -0400
libstdc++: optimize EH phase 2
In the ABI's two-phase EH model, first we walk the stack looking for a
handler, then we walk the stack running cleanups until we reach that
handler. In the cleanup phase, we shouldn't redundantly check the handlers
along the way, e.g. when walking through g():
void f() { throw 42; }
void g() { try { f(); } catch (void *) { } }
int main() { try { g(); } catch (int) { } }
libstdc++-v3/ChangeLog:
* libsupc++/eh_personality.cc (PERSONALITY_FUNCTION): Don't check
handlers in the cleanup phase.
Diff:
---
libstdc++-v3/libsupc++/eh_personality.cc | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/libstdc++-v3/libsupc++/eh_personality.cc b/libstdc++-v3/libsupc++/eh_personality.cc
index 12391e563d6..cc6bc048892 100644
--- a/libstdc++-v3/libsupc++/eh_personality.cc
+++ b/libstdc++-v3/libsupc++/eh_personality.cc
@@ -592,6 +592,10 @@ PERSONALITY_FUNCTION (int version,
// Zero filter values are cleanups.
saw_cleanup = true;
}
+ else if (actions == _UA_CLEANUP_PHASE)
+ // We checked the handlers in the search phase; if one of them
+ // matched, actions would also have _UA_HANDLER_FRAME set.
+ ;
else if (ar_filter > 0)
{
// Positive filter values are handlers.
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