Re: bzr commit into mysql-6.0-falcon-team branch (olav:2916) Bug#39419

[Hakan Kuecuekyilmaz]

Olav,

patch looks good. I have some questions; see inline.

On So, 2008-11-23 at 22:02 +0000, Olav Sandstaa wrote:
> #At file:///home/os136802/mysql/develop/repo/falcon-bug39419/ based on
> revid:john.embretsen@stripped
> 
>  2916 Olav Sandstaa	2008-11-23
>       Bug#39419 Falcon should not be compiled if compiler or options do not support
>       exceptions
>             
>       Adds a check to configure that verifies that the compiler with the
>       given compiler options will produce code that handles C++ exceptions. This
>       test is done by running a small program that throws an catches an exception.
>       If this program does not work correctly, configure will exit will an error 
>       message and needs to be re-run either with correct compiler options of with
>       Falcon disabled.
>       
>       Adds a check to the Falcon source code that tests that GCC and Windows
> compilers are
>       compiling with C++ exceptions enabled. This test will fail during compilation
> if the
>       compiler is not running with C++ exceptions enabled.
> modified:
>   storage/falcon/ha_falcon.cpp
>   storage/falcon/plug.in
> 
> per-file messages:
>   storage/falcon/ha_falcon.cpp
>     Added compile time test for checking that C++ exceptions are enabled. Currently
> only 
>     GCC and Microsoft compilers will be tested.
>   storage/falcon/plug.in
>     Added test to verify that the compiler with the given compiler options will
> produce code
>     that handles C++ exceptions.
> === modified file 'storage/falcon/ha_falcon.cpp'
> 
> === modified file 'storage/falcon/ha_falcon.cpp'
> --- a/storage/falcon/ha_falcon.cpp	2008-11-16 11:30:45 +0000
> +++ b/storage/falcon/ha_falcon.cpp	2008-11-23 22:02:22 +0000
> @@ -46,6 +46,11 @@
>  #include "ScaledBinary.h"
>  #include "BigInt.h"
>  
> +/* Verify that the compiler options have enabled C++ exception support */
> +#if (defined(__GNUC__) && !defined(__EXCEPTIONS)) || (defined (_MSVC_VER)
> && !defined (_CPPUNWIND))
> +#error Falcon needs to be compiled with support for C++ exceptions. Please check
> your compiler settings.
> +#endif
> +
>  //#define NO_OPTIMIZE
>  #define VALIDATE
>  //#define DEBUG_BACKLOG
> 
> === modified file 'storage/falcon/plug.in'
> --- a/storage/falcon/plug.in	2008-11-03 08:56:28 +0000
> +++ b/storage/falcon/plug.in	2008-11-23 22:02:22 +0000
> @@ -106,9 +106,6 @@
>      )
>    ])
>  
> -  CXXFLAGS=$ac_save_CXXFLAGS
> -  AC_LANG_POP([C++])
> -

* What is $ac_save_CXXFLAGS?
* What does AC_LANG_POP do?

>    # Falcon uses exceptions and STL.
>    CXXLDFLAGS="$CXXLDFLAGS $falcon_cxx_enable_stl"
>    FALCON_CXXFLAGS="$falcon_cxx_no_invalid_offsetof
> $falcon_cxx_enable_implicit_templates $falcon_cxx_enable_exceptions"
> @@ -119,6 +116,34 @@
>  
>    AC_SUBST([FALCON_CXXFLAGS])
>  
> +  # Check that C++ exceptions works in an executable by actually running a
> +  # compiled program and throwing and catching an exception
> +  CXXFLAGS=$FALCON_CXXFLAGS

What is the difference between $ac_save_CXXFLAGS and $FALCON_CXXFLAGS?

> +  AC_CACHE_CHECK([if compiler and compiler options support C++ exceptions for
> Falcon],
> +	            falcon_supported_by_compiler,[
> +  AC_TRY_RUN([
> +    int main() {
> +      try {
> +        throw 1;
> +      }
> +      catch (int) {
> +        return 0;
> +      }
> +      return -1; 
> +    }
> +  ], falcon_supported_by_compiler="yes",
> +     falcon_supported_by_compiler="no", )
> +  ])
> +
> +  if test "$falcon_supported_by_compiler" != "yes"; then
> +    echo "Falcon must be compiled with support for C++ exceptions enabled."
> +    echo "Please adjust your compiler flags or disable support for Falcon
> (--without-plugin-falcon)."
> +    exit 1
> +  fi
> +
> +  CXXFLAGS=$ac_save_CXXFLAGS
> +  AC_LANG_POP([C++])

You moved the above two lines down. Does $ac_save_CXXFLAGS collects the
CXXFLAGS we need? I guess AC_LANG_POP() tells me that we are done with
[C++] tests?

[cut]
-- 
Hakan Küçükyılmaz, Senior Software Engineer DBTG/MySQL +49 160
98953296
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