meson: fix builds against LLVM built without rtti

Building without rtti is a frought with peril, but it's something that
autotools supports so we need to support it too.

Since we've moved to version 0.44 as a whole we can use the meson
functionality for accessing random llvm-config options we can check for
rtti and add -fno-rtti to all C++ code accordingly.

Signed-off-by: Dylan Baker <dylan.c.baker@intel.com>

diff --git a/meson.build b/meson.build
index 2e10ed7..4019b21 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -1143,6 +1143,13 @@ if with_llvm
     '-DHAVE_LLVM=0x0@0@0@1@'.format(_llvm_version[0], _llvm_version[1]),
     '-DMESA_LLVM_VERSION_PATCH=@0@'.format(_llvm_patch),
   ]
+
+  # LLVM can be built without rtti, turning off rtti changes the ABI of C++
+  # programs, so we need to build all C++ code in mesa without rtti as well to
+  # ensure that linking works.
+  if dep_llvm.get_configtool_variable('has-rtti') == 'NO'
+    cpp_args('-fno-rtti')
+  endif
 elif with_amd_vk or with_gallium_radeonsi or with_gallium_swr
   error('The following drivers require LLVM: Radv, RadeonSI, SWR. One of these is enabled, but LLVM is disabled.')
 endif