Re: [ros-dev] 52061 [jgardou] [CMAKE], "According to gcc doc, if header.h is precompiled, the output should be named "header.h.gch" and not anything else.", Knowing it was the first step before actually doing it :-/

[Colin Finck]

jgardou(a)svn.reactos.org wrote:
>   -  set(_gch_filename
> "${_target_name}_${_FILE}.gch")
>  +  set(_gch_filename "${_FILE}.gch") 
Looks like we're going through the same mess of GNU precompiled headers, 
which we already had in rbuild:

1) Giving the GCH file a custom name.
    Problem: It is simply ignored in the build process.
2) Just renaming it to the name of the header file.
    Problem: If two modules use the same header file with different
    build options (like #defines), the compiler can only choose one
    precompiled header and we have a corrupted build.

The solution now is to give every GCH file an individual directory whose 
name contains the module name (like ".gch_smlib", this is what we 
currently have in rbuild).

Concluding from what I see in rbuild, please also note that the GCH file 
needs to be named "header.h.gch", not "header.gch". Your ${basename} 
variable sounds like this is not done either in the CMake branch.


- Colin

[Jérôme Gardou]

no, _basename is with .h here.

as for the other problem, it's the case. For now gcc falls back to using 
non precompiled header. But I have other plans, this is just a quick and 
dirty little thing.
cmake team will have some patches to deal with in weeks to come :-)

Le 02/06/2011 22:42, Colin Finck a écrit :
>  
>  jgardou(a)svn.reactos.org wrote:
> >   -  set(_gch_filename
> > "${_target_name}_${_FILE}.gch")
> >  +  set(_gch_filename "${_FILE}.gch") 
>  Looks like we're going through the same mess of GNU precompiled 
>  headers, which we already had in rbuild:
>
>  1) Giving the GCH file a custom name.
>     Problem: It is simply ignored in the build process.
>  2) Just renaming it to the name of the header file.
>     Problem: If two modules use the same header file with different
>     build options (like #defines), the compiler can only choose one
>     precompiled header and we have a corrupted build.
>
>  The solution now is to give every GCH file an individual directory 
>  whose name contains the module name (like ".gch_smlib", this is what 
>  we currently have in rbuild).
>
>  Concluding from what I see in rbuild, please also note that the GCH 
>  file needs to be named "header.h.gch", not "header.gch". Your 
>  ${basename} variable sounds like this is not done either in the CMake 
>  branch.
>
>
>  - Colin
>
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[Dmitry Gorbachev]

Maybe they are not so important -- when they were off for quite some
time due to a bug in rbuild, nobody ever noticed...