Re: [PATCH v2] capstone: use <capstone/capstone.h> instead of <capstone.h>

[Peter Maydell]

On Sun, 13 Nov 2022 at 20:10, Michael Tokarev <mjt@tls.msk.ru> wrote:
>
> The upcoming capstone 5.0 drops support for the old way
> of including its header, due to this change:
> https://github.com/capstone-engine/capstone/commit/6656bcb63ab4e87dc6079bd6b6b12cc8dd9b2ad8
> The official way is to use <capstone/capstone.h>
>
> This change has already been proposed before, see
> https://patchwork.kernel.org/project/qemu-devel/patch/20180215173539.11033-1-f4bug@amsat.org/
> but it didn't find its way into qemu at that time.
>
> On current systems, using <capstone/capstone.h> works
> now (despite the pkg-config-supplied -I/usr/include/capstone) -
> since on all systems capstone headers are put into capstone/
> subdirectory of a system include dir. So this change is
> compatible with both the obsolete way of including it
> and the only future way.

That's only true if capstone happened to be installed
into a system include directory subdirectory. That
is probably true for most distros, but it isn't
necessarily true when an end user has built and
installed capstone locally themselves.

In other words, this is a breaking non-back-compatible
change by capstone upstream, which we now need to work
around somehow :-(


> diff --git a/include/disas/capstone.h b/include/disas/capstone.h
> index e29068dd97..d8fdc5d537 100644
> --- a/include/disas/capstone.h
> +++ b/include/disas/capstone.h
> @@ -3,7 +3,7 @@
>
>  #ifdef CONFIG_CAPSTONE
>
> -#include <capstone.h>
> +#include <capstone/capstone.h>
>
>  #else
>
> diff --git a/meson.build b/meson.build
> index cf3e517e56..6f34c963f7 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -2680,12 +2680,7 @@ if not get_option('capstone').auto() or have_system or 
> have_user
>    capstone = dependency('capstone', version: '>=3.0.5',
>                          kwargs: static_kwargs, method: 'pkg-config',
>                          required: get_option('capstone'))
> -
> -  # Some versions of capstone have broken pkg-config file
> -  # that reports a wrong -I path, causing the #include to
> -  # fail later. If the system has such a broken version
> -  # do not use it.
> -  if capstone.found() and not cc.compiles('#include <capstone.h>',
> +  if capstone.found() and not cc.compiles('#include <capstone/capstone.h>',
>                                            dependencies: [capstone])
>      capstone = not_found
>      if get_option('capstone').enabled()

We can do something like

config_host_data.set('HAVE_CAPSTONE_CAPSTONE_H',
cc.has_header('capstone/capstone.h', depedencies: [capstone])

to check that this capstone really does have capstone/capstone.h,
for instance.

Dan: is there a reason why in commit 8f4aea712ffc4 you wrote
the "check that capstone.h really exists" check with cc.compiles
rather than cc.has_header ?

thanks
-- PMM