meson: rework mesa-clc=system handling

In theory you can build a driver using OpenCL kernels with a
-Dmesa-clc=system. That shouldn't require any LLVM/Clang/etc...

But the checks to find the pre-compiled mesa_clc & vtn_bindgen
binaries are in meson files or conditions only triggered if you build
with LLVM (:

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Tested-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Dylan Baker <None>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33014>

meson.build

@@ -306,24 +306,26 @@ with_any_broadcom = [
   with_broadcom_vk,
 ].contains(true)
 
-if get_option('intel-clc') != 'system' and get_option('precomp-compiler') != 'system'
+with_intel_vk_rt = get_option('intel-rt') \
+   .disable_auto_if(not with_intel_vk) \
+   .disable_if(get_option('intel-bvh-grl') and \
+               host_machine.cpu_family() != 'x86_64', \
+               error_message : 'Intel Ray Tracing is only supported on x86_64') \
+  .allowed()
+
+with_intel_bvh_grl = get_option('intel-bvh-grl')
+
+if get_option('intel-clc') != 'system' and \
+   get_option('precomp-compiler') != 'system' and \
+   with_intel_bvh_grl
   # Require intel-clc with Anv & Iris (for internal shaders)
   with_intel_clc = get_option('intel-clc') == 'enabled' or \
                    get_option('precomp-compiler') == 'enabled' or \
-                   with_intel_vk or with_gallium_iris
+                   with_intel_bvh_grl
 else
   with_intel_clc = false
 endif
 
-with_intel_vk_rt = get_option('intel-rt') \
-  .disable_auto_if(not with_intel_vk) \
-  .disable_if(host_machine.cpu_family() != 'x86_64', error_message : 'Intel Ray Tracing is only supported on x86_64') \
-  .allowed()
-
-if with_intel_vk_rt
-  with_intel_bvh_grl = get_option('intel-bvh-grl')
-endif
-
 with_any_intel = [
   with_gallium_crocus,
   with_gallium_i915,
@@ -825,7 +827,18 @@ else
   with_drivers_clc = false
 endif
 
-with_clc = get_option('mesa-clc') != 'auto' or with_microsoft_clc or with_intel_vk or with_gallium_iris or with_drivers_clc or with_gallium_asahi or with_asahi_vk or with_gallium_rusticl
+if get_option('mesa-clc') == 'system'
+  prog_mesa_clc = find_program('mesa_clc', native : true)
+  prog_vtn_bindgen = find_program('vtn_bindgen', native : true)
+  # Even with mesa-clc already built, rusticl still needs clc.
+  with_clc = with_gallium_rusticl
+else
+  with_clc = get_option('mesa-clc') != 'auto' or \
+             with_microsoft_clc or with_drivers_clc or \
+             with_gallium_iris or with_intel_vk or \
+             with_gallium_asahi or with_asahi_vk or \
+             with_gallium_rusticl
+endif
 
 dep_clc = null_dep
 if with_gallium_clover or with_clc

src/compiler/clc/meson.build

@@ -117,9 +117,11 @@ idep_mesaclc = declare_dependency(
   link_args : _idep_mesaclc_link_args,
 )
 
-if get_option('mesa-clc') == 'system'
-  prog_mesa_clc = find_program('mesa_clc', native : true)
-else
+if get_option('mesa-clc') != 'system' and (with_gallium_asahi or \
+                                           with_asahi_vk or \
+                                           with_intel_vk or \
+                                           with_gallium_iris or \
+                                           get_option('install-mesa-clc'))
   prog_mesa_clc = executable(
     'mesa_clc',
     ['mesa_clc.c'],

src/compiler/spirv/meson.build

@@ -77,14 +77,11 @@ spirv2nir = executable(
   install : with_tools.contains('nir'),
 )
 
-if get_option('mesa-clc') == 'system'
-  prog_vtn_bindgen = find_program('vtn_bindgen', native : true)
-# Due to the cross build issues in current meson, we only build vtn_bindgen when
-# building drivers that need it or mesa-clc is explictly required.
-#
-# XXX: Build by default once https://github.com/mesonbuild/meson/pull/12022
-# ships.
-elif get_option('mesa-clc') != 'auto' or with_gallium_asahi or with_asahi_vk or with_intel_vk or with_gallium_iris
+if get_option('mesa-clc') != 'system' and (with_gallium_asahi or \
+                                           with_asahi_vk or \
+                                           with_intel_vk or \
+                                           with_gallium_iris or \
+                                           get_option('install-mesa-clc'))
    prog_vtn_bindgen = executable(
      'vtn_bindgen',
      ['vtn_bindgen.c'],

src/intel/compiler/meson.build

@@ -167,6 +167,7 @@ idep_intel_compiler_brw = declare_dependency(
 )
 
 # For now this tool is only going to be used by Anv
+if with_intel_bvh_grl
   if get_option('intel-clc') == 'system' or get_option('precomp-compiler') == 'system'
     prog_intel_clc = find_program('intel_clc', native : true)
     dep_prog_intel_clc = []
@@ -196,6 +197,9 @@ elif with_intel_clc
     )
     dep_prog_intel_clc = [prog_intel_clc]
   endif
+else
+  dep_prog_intel_clc = []
+endif
 
 if with_tests
   test(