Make meson.override_find_program more cross compile friendly
#8664
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dcbaker
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| if isinstance(exe, mesonlib.File) or 'native' in kwargs: | ||
| for_machine = self.interpreter.machine_from_native_kwarg(kwargs) | ||
| else: | ||
| for_machine = exe.for_machine |
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I think we should error out if native kwarg does not match exe.for_machine.
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I thought about that too, but sometimes things for the host machine are "runs on the host machine" and sometimes they mean "runs for the host machine", compilers, cmake, pkg-config, and some other tools are all set as "host machine binaries" but they actually run on the build machine and produce output for the host machine. Not sure if that's a worthwile thing to handle or not?
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Hmmm, the more I think about it the more I think starting with the stricter behavior and relaxing it after we find a usecase might be better.
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Exactly what I was going to say.
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dcbaker
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We need to know whether we checked on the host or build machine, as they're not the same when cross compiling.
Currently we're not making use of this, but we will soon.
The subproject overrode a build (native) binary, but then the super project called find_program() without native : true, this means that the super expects a host binary, but gets a build binary.
We'll have use for this in a bit.
A program for the host machine should only override host machine binaries, and one for the build machine should only override build machine binaries. We don't need a native keyword argument here, because the Targets already know what machine they're for, and we can use that information. This is nice from an end user point of view as they don't need to know whether the binary is host or build, Meson abstracts that away.
…ogram` This is necessary when using a script (mesonlib.File) to override a program.
It's clearer, especially when considered with `dependency_overrides`, which is used for dependencies.
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As far as I remember, it was intentional to not have the In your example: exe_for_host = executable(..., native : false)
exe_for_build = executable(..., native : true)
meson.override_find_program('exe', exe_for_host)
meson.override_find_program('exe', exe_for_build)I think erroring is actually the right thing, but the message could be better. There is no point in doing On a similar topic, I had that PR: #10899. The idea is it only makes sense to override a program with something we can run. Could be a python script, an exe for build machine, or an exe for host machine and an exe wrapper is available. |
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Here's the problem, it's not really clear if being for BUILD means "runs natively" or "outputs for build". Certainly some HOST machine binaries are built for the HOST machine and need an exe wrapper, but others are very much not. Think of things like your compilers, linkers, strip, etc. There are also cases where programs generate different code depending on the platform/architecture they're generating for. flex and bison come to mind, where the windows versions do some trickery to make code that MSVC is happy with, but the *nix versions don't. |
I see, that makes more sense indeed. It can get useful together with #10938 too. |
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I'm closing this in favor of the version in my native subproject series |
Currently, Meson doesn't track the difference between a
find_programoverride for the build machine vs the host machine. So if you run some code like:then run
you'll get the exe your overwrote, even though that probably isn't what you meant. With this PR that is actually correctly tracked. The best part is that you don't need to pass a
nativeargument tooverride_find_programin most cases, as Meson already knows what the built binaries are for. However, when using a script (like a python script) you do need to set the machine, otherwise it's assumed to be for the HOST machine.