meson: Add support for using cmake for finding LLVM

Meson has support for using cmake as a finder for some dependencies,
including LLVM. Using cmake has a lot of advantages: it needs less meson
maintenance to keep working (even for llvm updates); it works more
sanely for cross compiles (as llvm-config is a compiled binary not a
shell script). Meson 0.51.0 also has a new generic variable getter that
can be used to get information from either cmake, pkg-config, or
config-tools dependencies, which is needed for cmake. We continue to
support using llvm-config if you don't have cmake installed, or if cmake
cannot find a suitable version.

Fixes: 0d59459432cf077d768164091318af8fb1612500
       ("meson: Force the use of config-tool for llvm")
Reviewed-by: Eric Engestrom <[email protected]>
(cherry picked from commit 5157a4276500c77e2210e853b262be1d1b30aedf)

3 files changed, 21 insertions, 11 deletions

diff --git a/src/gallium/drivers/swr/rasterizer/jitter/meson.build b/src/gallium/drivers/swr/rasterizer/jitter/meson.build
index aced4a1b735..6885c344939 100644
--- a/src/gallium/drivers/swr/rasterizer/jitter/meson.build
+++ b/src/gallium/drivers/swr/rasterizer/jitter/meson.build
@@ -1,4 +1,4 @@
-# Copyright © 2017-2018 Intel Corporation
+# Copyright © 2017-2019 Intel Corporation
 
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -19,14 +19,17 @@
 # SOFTWARE.
 
 
+if meson.version().version_compare('>=0.51')
+  _llvm_includedir = dep_llvm.get_variable(configtool : 'includedir', cmake : 'LLVM_INCLUDE_DIR')
+else
+  _llvm_includedir = dep_llvm.get_configtool_variable('includedir')
+endif
+
 gen_builder_hpp = custom_target(
   'gen_builder.hpp',
   input : [
     swr_gen_llvm_ir_macros_py,
-    join_paths(
-      dep_llvm.get_configtool_variable('includedir'), 'llvm', 'IR',
-      'IRBuilder.h'
-    )
+    join_paths(_llvm_includedir, 'llvm', 'IR', 'IRBuilder.h')
   ],
   output : 'gen_builder.hpp',
   command : [
diff --git a/src/gallium/state_trackers/clover/meson.build b/src/gallium/state_trackers/clover/meson.build
index 2ff060bf35b..8f751cbb414 100644
--- a/src/gallium/state_trackers/clover/meson.build
+++ b/src/gallium/state_trackers/clover/meson.build
@@ -1,4 +1,4 @@
-# Copyright © 2017-2018 Intel Corporation
+# Copyright © 2017-2019 Intel Corporation
 
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -25,6 +25,12 @@ if with_opencl_icd
   clover_cpp_args += '-DHAVE_CLOVER_ICD'
 endif
 
+if meson.version().version_compare('>=0.51')
+  _clang_resources = join_paths(dep_llvm.get_variable(cmake : 'LLVM_LIBRARY_DIR', configtool : 'libdir'), 'clang', dep_llvm.version(), 'include')
+else
+  _clang_resources = join_paths(dep_llvm.get_configtool_variable('libdir'), 'clang', dep_llvm.version(), 'include')
+endif
+
 libclllvm = static_library(
   'clllvm',
   files(
@@ -43,10 +49,7 @@ libclllvm = static_library(
     cpp_vis_args,
     '-DLIBCLC_INCLUDEDIR="@0@/"'.format(dep_clc.get_pkgconfig_variable('includedir')),
     '-DLIBCLC_LIBEXECDIR="@0@/"'.format(dep_clc.get_pkgconfig_variable('libexecdir')),
-    '-DCLANG_RESOURCE_DIR="@0@"'.format(join_paths(
-      dep_llvm.get_configtool_variable('libdir'), 'clang',
-      dep_llvm.version(), 'include',
-    )),
+    '-DCLANG_RESOURCE_DIR="@0@"'.format(_clang_resources),
   ],
   dependencies : [dep_llvm, dep_elf],
   override_options : clover_cpp_std,
diff --git a/src/gallium/targets/opencl/meson.build b/src/gallium/targets/opencl/meson.build
index 317ad8dab4a..676e0e13174 100644
--- a/src/gallium/targets/opencl/meson.build
+++ b/src/gallium/targets/opencl/meson.build
@@ -29,7 +29,11 @@ if with_ld_version_script
   opencl_link_deps += files('opencl.sym')
 endif
 
-llvm_libdir = dep_llvm.get_configtool_variable('libdir')
+if meson.version().version_compare('>=0.51')
+  llvm_libdir = dep_llvm.get_variable(configtool : 'libdir', cmake : 'LLVM_LIBRARY_DIR')
+else
+  llvm_libdir = dep_llvm.get_configtool_variable('libdir')
+endif
 
 opencl_libname = with_opencl_icd ? 'MesaOpenCL' : 'OpenCL'