[patch #8260] Macros to check GCC-compatible built-in functions, function and variable attributes

URL:
  <http://savannah.gnu.org/patch/?8260>

                 Summary: Macros to check GCC-compatible built-in functions,
function and variable attributes
                 Project: GNU Autoconf Archive
            Submitted by: None
            Submitted on: Mon 16 Dec 2013 04:28:54 PM UTC
                Priority: 5 - Normal
                  Status: None
             Assigned to: None
        Originator Email: [email protected]
             Open/Closed: Open
         Discussion Lock: Any

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Details:

This patch-set adds three macros:

- AX_GCC_BUILTIN(BUILTIN)

This macro is used to detect GCC-compatible built-in functions (e.g.
AX_GCC_BUILTIN([__builtin_expect]) to check for __builtin_expect()). Since
those functions are not treated like normal functions they cannot be checked
using common autoconf macros. The macro description contains the relatively
long list of supported built-ins; unknown built-ins can also be checked but
the result might be wrong or meaningless, the user will be warned in this
case.

- AX_GCC_FUNC_ATTRIBUTE(ATTRIBUTE)

This macro is used to detect GCC-compatible function attributes (e.g.
AX_GCC_FUNC_ATTRIBUTE([pure]) to check for __attribute__((pure))). Using
invalid or unknown attributes usually generates warnings instead of compiler
errors hence this macro provides proper attribute-specific checks to ensure
that the required attribute is correctly supported. The macro header contains
the list of supported attributes. Unknown attributes can also be checked but
the result might be wrong or meaningless, the user will be warned in this
case

- AX_GCC_VAR_ATTRIBUTE(ATTRIBUTE)

This macro is used to detect GCC-compatible variable attributes (e.g.
AX_GCC_VAR_ATTRIBUTE([unused]) to check for __attribute__((unused))). It works
in the same way as the previous one.

The macros all define HAVE_* macros when the checked builtin/attribute is
found and also properly set ax_cv_have_* variables. They have been tested
across multiple versions of GCC and LLVM/clang to ensure that they detect the
available builtins/attributes correctly.

Finally all macros are available under the all-permissive license.



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File Attachments:


-------------------------------------------------------
Date: Mon 16 Dec 2013 04:28:54 PM UTC  Name:
0001-Add-a-macro-for-checking-GCC-compatible-built-in-fun.patch  Size: 6kB  
By: None

<http://savannah.gnu.org/patch/download.php?file_id=29974>
-------------------------------------------------------
Date: Mon 16 Dec 2013 04:28:54 PM UTC  Name:
0003-Add-a-macro-to-check-GCC-compatible-variable-attribu.patch  Size: 5kB  
By: None

<http://savannah.gnu.org/patch/download.php?file_id=29975>
-------------------------------------------------------
Date: Mon 16 Dec 2013 04:28:54 PM UTC  Name:
0002-Add-a-macro-for-checking-GCC-compatible-function-att.patch  Size: 8kB  
By: None

<http://savannah.gnu.org/patch/download.php?file_id=29976>

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