[CMake] Detailed graphviz graph?

[Jan Wielemaker]

On 03/10/18 09:53, Eric Noulard wrote:
>
>         - I have an ordinary executable target `swipl`
>         - To run, this requires a boot file `swipl.prc` that is created
>           by calling `swipl -b ...`
>
>
> Hum... I don't get it.
> For running? creating? target "swipl" you need to run it?
> There is a chicken & eggs problem or I misread what you said?
>
>         - I'd like to run `swipl` for creating a library index file.
>
>     So, these targets need to be built in the order above.  It turns
>     out that sometimes step 3 runs before 2 completes.  At least, this
>     happens on MacOS using cmake 3.11.2.  So far I haven't seen it on
>     Linux (where I use 3.10).  The definition goes like this:
>
>     add_custom_command(
>           OUTPUT  swipl.prc
>           COMMAND swipl -O -b ${SWIPL_BOOT_ROOT}/init.pl <http://init.pl>
>           DEPENDS swipl ${SWIPL_BOOT_FILES}
>     )
>
>     add_custom_command(
>           OUTPUT  ${PL_LIB_INDEX}
>           COMMAND swipl -f none -g
>     "\"make_library_index('${SWIPL_LIBRARY_ROOT}')\"" -t halt
>           DEPENDS swipl.prc ${PL_LIB_FILES_ALL}
>     )
>
>     add_custom_target(prolog_products ALL
>           DEPENDS swipl.prc ${PL_LIB_INDEX}
>     )
>
>     The first specifies building swipl.prc, the second the index
>     file and the custom target ensures the default build will
>     create both files.  I don't see what is wrong and a visual
>     dependency graph might reveal this ...
>
>
> Are those three add_custom_xxx in the same directory?
> DEPENDS for custom_xxx do not cross directory.

So this was not the problem. The problem was that on the Mac I had build
the system before using the autoconf/make suite, which had created
`swipl.prc` in the source tree. Now, this is the second time I've been
fooled by this:

If a custom command has a DEPENDS, this points at the
CMAKE_CURRENT_SOURCE_DIR if the file exists there and at the
CMAKE_CURRENT_BINARY_DIR otherwise.  This makes sense, but
easily leads to things that are hard to figure out ...

Thanks. In particular for pointing at Ninja's tools for figuring out
dependencies.

	Cheers --- Jan