meson: Use dep_llvm when finding clang modules

When cross-compiling OpenCL support, clover will encode the LLVM library
path so that it can add the proper directory (containing opencl-c.h) to
the include path during runtime compilation of programs. In order for
that to work, the LLVM library directory needs to be an absolute path in
the host filesystem.

However, during cross-compilation the LLVM library directory will also
be used to find the clang modules to link against. But at build time the
clang modules will have to be looked up in th LLVM library directory
within the host sysroot, which is a cross-compilation staging area that
is located in an arbitrary directory on the build filesystem.

However, the library search path provided by the dep_llvm dependency
contains the correct path to the clang modules at build time, so the
dependency can be passed to the cc.find_library() command to properly
check for the existence of the library and whether it can actually be
linked to.

NOTE: This depends on a patch that hasn't been merged into Meson yet.

Signed-off-by: Thierry Reding <treding@nvidia.com>

2 files changed, 14 insertions, 16 deletions

diff --git a/meson.build b/meson.build
index 92e45d28640..1a24591f051 100644
--- a/meson.build
+++ b/meson.build
@@ -25,7 +25,7 @@ project(
     [find_program('python', 'python2', 'python3'), 'bin/meson_get_version.py']
   ).stdout(),
   license : 'MIT',
-  meson_version : '>= 0.46',
+  meson_version : '>= 0.50',
   default_options : ['buildtype=debugoptimized', 'b_ndebug=if-release', 'c_std=c99', 'cpp_std=c++14']
 )
 
diff --git a/src/gallium/targets/opencl/meson.build b/src/gallium/targets/opencl/meson.build
index 907cc74337d..a1f8680c88c 100644
--- a/src/gallium/targets/opencl/meson.build
+++ b/src/gallium/targets/opencl/meson.build
@@ -29,8 +29,6 @@ if with_ld_version_script
   opencl_link_deps += files('opencl.sym')
 endif
 
-llvm_libdir = dep_llvm.get_configtool_variable('libdir')
-
 opencl_libname = with_opencl_icd ? 'MesaOpenCL' : 'OpenCL'
 
 libopencl = shared_library(
@@ -43,19 +41,19 @@ libopencl = shared_library(
   dependencies : [
     idep_mesautil,
     dep_clock, dep_dl, dep_unwind, dep_elf,
-    cpp.find_library('clangCodeGen', dirs : llvm_libdir),
-    cpp.find_library('clangFrontendTool', dirs : llvm_libdir),
-    cpp.find_library('clangFrontend', dirs : llvm_libdir),
-    cpp.find_library('clangDriver', dirs : llvm_libdir),
-    cpp.find_library('clangSerialization', dirs : llvm_libdir),
-    cpp.find_library('clangParse', dirs : llvm_libdir),
-    cpp.find_library('clangSema', dirs : llvm_libdir),
-    cpp.find_library('clangAnalysis', dirs : llvm_libdir),
-    cpp.find_library('clangAST', dirs : llvm_libdir),
-    cpp.find_library('clangASTMatchers', dirs : llvm_libdir),
-    cpp.find_library('clangEdit', dirs : llvm_libdir),
-    cpp.find_library('clangLex', dirs : llvm_libdir),
-    cpp.find_library('clangBasic', dirs : llvm_libdir),
+    cpp.find_library('clangCodeGen', dependencies : dep_llvm),
+    cpp.find_library('clangFrontendTool', dependencies : dep_llvm),
+    cpp.find_library('clangFrontend', dependencies : dep_llvm),
+    cpp.find_library('clangDriver', dependencies : dep_llvm),
+    cpp.find_library('clangSerialization', dependencies : dep_llvm),
+    cpp.find_library('clangParse', dependencies : dep_llvm),
+    cpp.find_library('clangSema', dependencies : dep_llvm),
+    cpp.find_library('clangAnalysis', dependencies : dep_llvm),
+    cpp.find_library('clangAST', dependencies : dep_llvm),
+    cpp.find_library('clangASTMatchers', dependencies : dep_llvm),
+    cpp.find_library('clangEdit', dependencies : dep_llvm),
+    cpp.find_library('clangLex', dependencies : dep_llvm),
+    cpp.find_library('clangBasic', dependencies : dep_llvm),
   ],
   version : '@0@.0.0'.format(opencl_version),
   install : true,