[Mesa-dev] [PATCH] configure.ac: set -O0 on --enable-debug

[Nicolai Hähnle]

On 16.10.2017 20:31, Miklós Máté wrote:
> On 16/10/17 13:21, Emil Velikov wrote:
>> Hi Miklós,
>>
>> On 15 October 2017 at 18:46, Miklós Máté <mtmkls at gmail.com> wrote:
>>> Autoconf sets CFLAGS="-g -O2" by default.
>>>
>>> Signed-off-by: Miklós Máté <mtmkls at gmail.com>
>>> ---
>>>   configure.ac | 4 ++++
>>>   1 file changed, 4 insertions(+)
>>>
>>> diff --git a/configure.ac b/configure.ac
>>> index 62d33a1941..c833d258ed 100644
>>> --- a/configure.ac
>>> +++ b/configure.ac
>>> @@ -522,6 +522,8 @@ if test "x$enable_debug" = xyes; then
>>>           fi
>>>           if ! echo "$CFLAGS" | grep -q -e '-O'; then
>>>               CFLAGS="$CFLAGS -O0"
>>> +        else
>>> +            CFLAGS=`echo $CFLAGS | sed -e s/-O./-O0/`
>>>           fi
>>>       fi
>>>       if test "x$GXX" = xyes; then
>>> @@ -530,6 +532,8 @@ if test "x$enable_debug" = xyes; then
>>>           fi
>>>           if ! echo "$CXXFLAGS" | grep -q -e '-O'; then
>>>               CXXFLAGS="$CXXFLAGS -O0"
>>> +        else
>>> +            CXXFLAGS=`echo $CXXFLAGS | sed -e s/-O./-O0/`
>> Being the person who added -O0 in the first place I have to agree with 
>> others.
>> I don't think this is a good idea. But let me try to explain it from
>> another angle:
>>
>> Regardless of the build system used, a general rule should apply - the
>> user has the final say.
>> Namely: if the user has set a optimisation level/flags in C*FLAGS
>> those must be honoured.
>>
>> Yes it may be a bit confusing, if the use asks for "debug" build, yet
>> they explicitly set -O2/etc.
>>
>> HTH
>> Emil
> 
> I thought the intent was to always set -O0 when called with --enable-debug.

FYI, a typical use-case is a build that is optimized but has assertions 
enabled.

Cheers,
Nicolai


> 
> Sorry for the misunderstanding.
> 
> MM
> 
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> mesa-dev at lists.freedesktop.org
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