[2/2] Do not pass -DNDEBUG to Python compilations in development mode

  The Python CFLAGS include -DNDEBUG.  This was apparently done
intentionally -- setting the flags is done manually because, according
to a comment, python-config passes too many things to the compiler
(which is true).

Per PR python/20445, this patch changes configure so that -DNDEBUG is
only used by release builds.  This probably doesn't have very much
effect in practice, but I did see that some Python headers use assert,
so perhaps it will give some safety.

Tested by rebuilding and re-running gdb.python/*.exp on x86-64 Fedora 28.

ChangeLog
2018-09-16  Tom Tromey  <tom@tromey.com>

	PR python/20445:
	* configure: Rebuild.
	* configure.ac: Conditionally use -DNDEBUG for Python.
---
 gdb/ChangeLog    | 6 ++++++
 gdb/configure    | 6 +++++-
 gdb/configure.ac | 6 +++++-
 3 files changed, 16 insertions(+), 2 deletions(-)
  

Hi Tom,

On Sun, Sep 16, 2018 at 12:45:02PM -0600, Tom Tromey wrote:
> The Python CFLAGS include -DNDEBUG.  This was apparently done
> intentionally -- setting the flags is done manually because, according
> to a comment, python-config passes too many things to the compiler
> (which is true).
> 
> Per PR python/20445, this patch changes configure so that -DNDEBUG is
> only used by release builds.  This probably doesn't have very much
> effect in practice, but I did see that some Python headers use assert,
> so perhaps it will give some safety.
> 
> Tested by rebuilding and re-running gdb.python/*.exp on x86-64 Fedora 28.
> 
> ChangeLog
> 2018-09-16  Tom Tromey  <tom@tromey.com>
> 
> 	PR python/20445:
> 	* configure: Rebuild.
> 	* configure.ac: Conditionally use -DNDEBUG for Python.
> ---
>  gdb/ChangeLog    | 6 ++++++
>  gdb/configure    | 6 +++++-
>  gdb/configure.ac | 6 +++++-
>  3 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/gdb/configure b/gdb/configure
> index e011b77414b..2fb69a8eda6 100755
> --- a/gdb/configure
> +++ b/gdb/configure
> @@ -10762,7 +10762,11 @@ $as_echo "#define HAVE_PYTHON 1" >>confdefs.h
>    # would make the python-related objects be compiled differently from the
>    # rest of GDB (e.g., -O2 and -fPIC).
>    if test "${GCC}" = yes; then
> -    tentative_python_cflags="-fno-strict-aliasing -DNDEBUG -fwrapv"
> +    tentative_python_cflags="-fno-strict-aliasing -fwrapv"
> +    # Python headers recommend -DNDEBUG, but it's unclear if that just
> +    # refers to building Python itself.  In release mode, though, it
> +    # doesn't hurt for the Python code in gdb to follow.
> +    $development || tentative_python_cflags="tentative_python_cflags -DNDEBUG"

Are we missing a '$' before tentative_python_cflags in the string,
by any chance?

>    fi
>  
>    if test "x${tentative_python_cflags}" != x; then
> diff --git a/gdb/configure.ac b/gdb/configure.ac
> index f658da84e32..0709b1ff720 100644
> --- a/gdb/configure.ac
> +++ b/gdb/configure.ac
> @@ -965,7 +965,11 @@ if test "${have_libpython}" != no; then
>    # would make the python-related objects be compiled differently from the
>    # rest of GDB (e.g., -O2 and -fPIC).
>    if test "${GCC}" = yes; then
> -    tentative_python_cflags="-fno-strict-aliasing -DNDEBUG -fwrapv"
> +    tentative_python_cflags="-fno-strict-aliasing -fwrapv"
> +    # Python headers recommend -DNDEBUG, but it's unclear if that just
> +    # refers to building Python itself.  In release mode, though, it
> +    # doesn't hurt for the Python code in gdb to follow.
> +    $development || tentative_python_cflags="tentative_python_cflags -DNDEBUG"
>    fi
>  
>    if test "x${tentative_python_cflags}" != x; then
> -- 
> 2.17.1
  

>>>>> "Joel" == Joel Brobecker <brobecker@adacore.com> writes:

Joel> Are we missing a '$' before tentative_python_cflags in the string,
Joel> by any chance?

Yes, oops.  I wonder how that slipped through.

Tom
  

>>>>> "Tom" == Tom Tromey <tom@tromey.com> writes:

>>>>> "Joel" == Joel Brobecker <brobecker@adacore.com> writes:
Joel> Are we missing a '$' before tentative_python_cflags in the string,
Joel> by any chance?

Tom> Yes, oops.  I wonder how that slipped through.

Obviously I did not test in release mode.
I've fixed the bug and tried it both ways.

Tom
  

> >>>>> "Joel" == Joel Brobecker <brobecker@adacore.com> writes:
> Joel> Are we missing a '$' before tentative_python_cflags in the string,
> Joel> by any chance?
> 
> Tom> Yes, oops.  I wonder how that slipped through.
> 
> Obviously I did not test in release mode.
> I've fixed the bug and tried it both ways.

Thanks Tom. Other than this comment, I had no other comment so,
now that it is fixed and tested, I think you can push.
  

>>>>> "Joel" == Joel Brobecker <brobecker@adacore.com> writes:

>> >>>>> "Joel" == Joel Brobecker <brobecker@adacore.com> writes:
Joel> Are we missing a '$' before tentative_python_cflags in the string,
Joel> by any chance?
>> 
Tom> Yes, oops.  I wonder how that slipped through.
>> 
>> Obviously I did not test in release mode.
>> I've fixed the bug and tried it both ways.

Joel> Thanks Tom. Other than this comment, I had no other comment so,
Joel> now that it is fixed and tested, I think you can push.

I'd already done it since it seemed pretty clear.

Tom