Revised patch with _GLIBCXX_COLD added at the end.
```
commit 3dc9f9a8461b1c88e991ceb517e5fdd81f268d1e
Author: Aditya Kumar <1894981+hiradi...@users.noreply.github.com>
Date: Thu Aug 13 09:41:34 2020 -0700
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.
Similarly for __cxa_guard_release and __cxa_guard_abort
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
@@ -35,20 +35,21 @@
// The datestamp of the C++ library in compressed ISO date format.
#define __GLIBCXX__
// Macros for various attributes.
// _GLIBCXX_PURE
// _GLIBCXX_CONST
// _GLIBCXX_NORETURN
// _GLIBCXX_NOTHROW
// _GLIBCXX_VISIBILITY
+// _GLIBCXX_COLD
#ifndef _GLIBCXX_PURE
# define _GLIBCXX_PURE __attribute__ ((__pure__))
#endif
#ifndef _GLIBCXX_CONST
# define _GLIBCXX_CONST __attribute__ ((__const__))
#endif
#ifndef _GLIBCXX_NORETURN
# define _GLIBCXX_NORETURN __attribute__ ((__noreturn__))
@@ -67,20 +68,24 @@
#define _GLIBCXX_HAVE_ATTRIBUTE_VISIBILITY
#if _GLIBCXX_HAVE_ATTRIBUTE_VISIBILITY
# define _GLIBCXX_VISIBILITY(V) __attribute__ ((__visibility__ (#V)))
#else
// If this is not supplied by the OS-specific or CPU-specific
// headers included below, it will be defined to an empty default.
# define _GLIBCXX_VISIBILITY(V) _GLIBCXX_PSEUDO_VISIBILITY(V)
#endif
+#ifndef _GLIBCXX_COLD
+# define _GLIBCXX_COLD __attribute__ ((cold))
+#endif
+
// Macros for deprecated attributes.
// _GLIBCXX_USE_DEPRECATED
// _GLIBCXX_DEPRECATED
// _GLIBCXX17_DEPRECATED
// _GLIBCXX20_DEPRECATED( string-literal )
#ifndef _GLIBCXX_USE_DEPRECATED
# define _GLIBCXX_USE_DEPRECATED 1
#endif
#if defined(__DEPRECATED) && (__cplusplus >= 201103L)
diff --git a/libstdc++-v3/libsupc++/cxxabi.h b/libstdc++-v3/libsupc++/cxxabi.h
index 000713ecd..24c1366e2 100644
--- a/libstdc++-v3/libsupc++/cxxabi.h
+++ b/libstdc++-v3/libsupc++/cxxabi.h
@@ -108,27 +108,27 @@ namespace __cxxabiv1
__cxa_vec_delete2(void* __array_address, size_t __element_size,
size_t __padding_size, __cxa_cdtor_type __destructor,
void (*__dealloc) (void*));
void
__cxa_vec_delete3(void* __array_address, size_t __element_size,
size_t __padding_size, __cxa_cdtor_type __destructor,
void (*__dealloc) (void*, size_t));
int
- __cxa_guard_acquire(__guard*);
+ __cxa_guard_acquire(__guard*) _GLIBCXX_COLD;
void
- __cxa_guard_release(__guard*) _GLIBCXX_NOTHROW;
+ __cxa_guard_release(__guard*) _GLIBCXX_NOTHROW _GLIBCXX_COLD;
void
- __cxa_guard_abort(__guard*) _GLIBCXX_NOTHROW;
+ __cxa_guard_abort(__guard*) _GLIBCXX_NOTHROW _GLIBCXX_COLD;
// DSO destruction.
int
__cxa_atexit(void (*)(void*), void*, void*) _GLIBCXX_NOTHROW;
void
__cxa_finalize(void*);
// TLS destruction.
int
```
From: Aditya K
Sent: Thursday, August 13, 2020 10:47 AM
To: Jeff Law via Gcc-patches <gcc-patches@gcc.gnu.org>; jwakely....@gmail.com
<jwakely....@gmail.com>
Subject: Add cold attribute to one time construction APIs
This would help compiler optimize local static objects.
```
commit e2f299679ddf56a6d6d71ea9d589cd76b2ca107b
Author: Aditya Kumar <1894981+hiradi...@users.noreply.github.com>
Date: Thu Aug 13 09:41:34 2020 -0700
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.
Similarly for __cxa_guard_release and __cxa_guard_abort
diff --git a/libstdc++-v3/include/bits/c++config
b/libstdc++-v3/include/bits/c++config
index b1fad59d4..359e955a7 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -39,20 +39,24 @@
// Macros for various attributes.
// _GLIBCXX_PURE
// _GLIBCXX_CONST
// _GLIBCXX_NORETURN
// _GLIBCXX_NOTHROW
// _GLIBCXX_VISIBILITY
#ifndef _GLIBCXX_PURE
# define _GLIBCXX_PURE __attribute__ ((__pure__))
#endif
+#ifndef _GLIBCXX_COLD
+# define _GLIBCXX_COLD __attribute__ ((cold))
+#endif
+
#ifndef _GLIBCXX_CONST
# define _GLIBCXX_CONST __attribute__ ((__const__))
#endif
#ifndef _GLIBCXX_NORETURN
# define _GLIBCXX_NORETURN __attribute__ ((__noreturn__))
#endif
// See below for C++
#ifndef _GLIBCXX_NOTHROW
diff --git a/libstdc++-v3/libsupc++/cxxabi.h b/libstdc++-v3/libsupc++/cxxabi.h
index 000713ecd..24c1366e2 100644
--- a/libstdc++-v3/libsupc++/cxxabi.h
+++ b/libstdc++-v3/libsupc++/cxxabi.h
@@ -108,27 +108,27 @@ namespace __cxxabiv1
__cxa_vec_delete2(void* __array_address, size_t __element_size,
size_t __padding_size, __cxa_cdtor_type __destructor,
void (*__dealloc) (void*));
void
__cxa_vec_delete3(void* __array_address, size_t __element_size,
size_t __padding_size, __cxa_cdtor_type __destructor,
void (*__dealloc) (void*, size_t));
int
- __cxa_guard_acquire(__guard*);
+ __cxa_guard_acquire(__guard*) _GLIBCXX_COLD;
void
- __cxa_guard_release(__guard*) _GLIBCXX_NOTHROW;
+ __cxa_guard_release(__guard*) _GLIBCXX_NOTHROW _GLIBCXX_COLD;
void
- __cxa_guard_abort(__guard*) _GLIBCXX_NOTHROW;
+ __cxa_guard_abort(__guard*) _GLIBCXX_NOTHROW _GLIBCXX_COLD;
// DSO destruction.
int
__cxa_atexit(void (*)(void*), void*, void*) _GLIBCXX_NOTHROW;
void
__cxa_finalize(void*);
// TLS destruction.
int
```
