Brad King <brad.king@...> writes:
>
> On 3/19/2012 2:25 PM, Eric Noulard wrote:
> > 2012/3/19 Brad King<brad.king@...>:
> >> Can you enumerate use cases when the order of objects matters? Unlike
> >> static libraries *all* objects will be included. If there are duplicate
> >> symbols it is an error. If there are not duplicate symbols then how
> >> does order matter?
> >
> > The custom command likn step looks like:
> > COMMAND ${CMAKE_LINKER} --oformat binary -Ttext ${BM_IMAGE_ADDRESS}
> > -melf_i386 -e _start -o ${BM_APPNAME}.bin ${BM_STARTUPOBJ}
> > --start-group $<TARGET_LINKER_FILE:system> $<TARGET_LINKER_FILE:xc>
> > $<TARGET_LINKER_FILE:${BM_APPNAME}> --end-group ${BM_LDSCRIPT}
> >
> > ${BM_STARTUPOBJ} is the specific object file compiled on its own using
> > custom command.
>
> I can imagine some cross compiling toolchains may want the object with
> the entry point to come first.
>
> > Now that I think about it, before that I was forced to create a custom
> > command in order
> > to compile the file ('with the same option as the one compiled by
add_library)
> > but now I will be able to build an "OBJECT library" containing a single file
> > and refer to it using $<TARGET_OBJECTS:objlib> which is perfectly fine for
> > ensuring the ordering I may need for the link step.
>
> Note that $<TARGET_OBJECTS:...> is not a full generator expression that
> can be used from add_custom_command. That is also reserved for the
> future (which is why I chose that syntax). Currently it is just a
> special source file syntax recognized by add_library and add_executable.
>
Are there any plans to add support for using object lists in custom commands
yet?
I need to create a custom type of library from objects created using a cross
compiling toolchain, so I would like to do something like:
ADD_LIBRARY( myLibObjects OBJECT a.cpp b.cpp ) # creates a.cpp.o and b.cpp.o
ADD_CUSTOM_COMMAND( OUTPUT myLib
COMMAND myCustomArchiver --objects
$<TARGET_OBJECTS:myLibObjects> --output myLib ..
DEPENDS $<TARGET_OBJECTS:myLibObjects>
) # puts a.cpp.o and b.cpp.o in custom library myLib
ADD_CUSTOM_TARGET( myLib_created ALL DEPENDS myLib )
Best regards,
Ruben
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