[Mesa-dev] [PATCH] configure.ac: Drop LLVM compiler flags more radically

[Eero Tamminen]

Hi,

On 10.02.2017 02:59, Michel Dänzer wrote:
> On 09/02/17 10:50 PM, Emil Velikov wrote:
>> On 9 February 2017 at 08:07, Michel Dänzer <michel at daenzer.net> wrote:
>>> From: Michel Dänzer <michel.daenzer at amd.com>
>>>
>>> Drop all -m*, -W*, -O*, -g* and -f* flags, with the exception of
>>> -fno-rtti, which must be used if it's part of the llvm-config --cxxflags
>>> output. We don't want LLVM to dictate the flags we use, and it can even
>>> cause build failures, e.g. if LLVM and Mesa are built with different
>>> compilers.

Out of curiosity, where this stuff is applied?

(If you're removing all of them, result is hard to debug, non-optimized 
binary...)


>> Yes, please !
>> Reviewed-by: Emil Velikov <emil.velikov at collabora.com>
>
>
>> Out of curiosity:
>> Are you speaking of personal experience ? What was stored in the
>> c/cpp/cxx flags that triggered build failure ?
>
> Building LLVM with clang 4.0 resulted in llvm-config --cxxflags
> containing -Wstring-conversion and -fcolor-diagnostics, which aren't
> supported by gcc 6.3.

There are generic flags that have been supported by few decades, which 
are not going to change, like -O[1-3], -Wall, -g.  Only the specific 
optimization & warning flags are something that differ between compiler 
versions (as new ones get added).


	- Eero