On 18/08/20 15:35 +0100, Jonathan Wakely wrote:
>On 17/08/20 18:15 +0000, Aditya K via Libstdc++ wrote:
>>This would help compiler optimize local static objects.
>>
>>Added changelog.
>
>Please don't :-)
>
>GCC patch policies always said NOT to change the ChangeLog in the
>patch, because the ChangeLog files change so rapidly that it means by
>the time you've sent the patch, it no longer applies.
>
>Current GCC policies are that NOBODY changes the ChangeLog files, they
>are autogenerated from Git commit logs once per day.
>
>So please just include the proposed ChangeLog entry as the Git commit
>message in the body of your email.
>
>Patch for libstdc++ need to go to both the libstdc++ list and the
>gcc-patches list, in the same email. Not sent once to each list as
>separate emails.
>
>>
>>```
>From c6cba40e0434147db89d3af05b598782cde651e3 Mon Sep 17 00:00:00 2001
>>From: Aditya Kumar <1894981+hiraditya@users.noreply.github.com>
>>Date: Thu, 13 Aug 2020 09:41:34 -0700
>>Subject: [PATCH] Add cold attribute to one time construction APIs
>>
>>__cxa_guard_acquire is used for only one purpose,
>>namely guarding local static variable initialization,
>>and since that purpose is definitionally cold, it should be attributed as cold.
>
>Definitionally isn't a word. Attributed is a word, but it doesn't mean
>marked with an attribute.
>
>>Similarly for __cxa_guard_release and __cxa_guard_abort
>>---
>>libstdc++-v3/ChangeLog              | 5 +++++
>>libstdc++-v3/include/bits/c++config | 5 +++++
>>libstdc++-v3/libsupc++/cxxabi.h     | 6 +++---
>>3 files changed, 13 insertions(+), 3 deletions(-)
>>
>>diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
>>index fe6884bf3..86b707ac7 100644
>>--- a/libstdc++-v3/ChangeLog
>>+++ b/libstdc++-v3/ChangeLog
>>@@ -1,3 +1,8 @@
>>+2020-08-17  Aditya Kumar  <hiraditya@msn.com>
>>+	* libstdc++-v3/include/bits/c++config: Add _GLIBCXX_NOTHROW attribute
>>+	* libstdc++-v3/libsupc++/cxxabi.h (__cxa_guard_acquire, __cxa_guard_release,
>>+	__cxa_guard_abort): Add _GLIBCXX_NOTHROW attribute.
>
>The changelog format is wrong. There should be a blank line after the
>date+author line, and you're adding _GLIBCXX_COLD not
>_GLIBCXX_NOTHROW. But it shouldn't be here at all as explained above.
>
>>2020-08-14  Lewis Hyatt  <lhyatt@gmail.com>
>>
>>	* testsuite/lib/libstdc++.exp: Use the new option
>>diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
>>index b1fad59d4..f6f954eef 100644
>>--- a/libstdc++-v3/include/bits/c++config
>>+++ b/libstdc++-v3/include/bits/c++config
>>@@ -42,6 +42,7 @@
>>//   _GLIBCXX_NORETURN
>>//   _GLIBCXX_NOTHROW
>>//   _GLIBCXX_VISIBILITY
>>+//   _GLIBCXX_COLD
>>#ifndef _GLIBCXX_PURE
>># define _GLIBCXX_PURE __attribute__ ((__pure__))
>>#endif
>>@@ -74,6 +75,10 @@
>># define _GLIBCXX_VISIBILITY(V) _GLIBCXX_PSEUDO_VISIBILITY(V)
>>#endif
>>
>>+#ifndef _GLIBCXX_COLD
>>+# define _GLIBCXX_COLD __attribute__ ((cold))
>>+#endif
>
>"cold" is not a reserved name so this needs to be __cold__.

I've just pushed the attached patch which ensures we don't use the
non-reserved form of the attribute.

Tested x86_64-linux, committed to trunk.