Add cold attribute to one time construction APIs

2020-08-13 Thread Aditya K via Gcc-patches
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
```

Re: Add cold attribute to one time construction APIs

2020-08-13 Thread Aditya K via Gcc-patches
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 ; 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

Re: Add cold attribute to one time construction APIs

2020-08-13 Thread Aditya K via Gcc-patches
FYI libc++ patch sent for review: https://reviews.llvm.org/D85873

Re: Add cold attribute to one time construction APIs

2020-08-13 Thread Aditya K via Gcc-patches
sure.
--

From: Jonathan Wakely 
Sent: Thursday, August 13, 2020 11:13 AM
To: Aditya K 
Cc: libstdc++ ; gcc-patches 
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  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 ; 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 _