sure. -- From: Jonathan Wakely <jwakely....@gmail.com> Sent: Thursday, August 13, 2020 11:13 AM To: Aditya K <hiradi...@msn.com> Cc: libstdc++ <libstd...@gcc.gnu.org>; gcc-patches <gcc-patches@gcc.gnu.org> Subject: Re: Add cold attribute to one time construction APIs Please CC the libstdc++ list on all libstdc++ patches.
On Thu, 13 Aug 2020 at 17:51, Aditya K <hiradi...@msn.com> wrote: > > 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 > ```
