[Mesa-dev] [PATCH v4 2/4] meson: disable x86 asm in fewer cases.

[Dylan Baker]

This patch allows building asm for x86 on x86_64 platforms, when the
operating system is the same. Previously cross compile always turned off
assembly. This allows using a cross file to cross compile x86 binaries
on x86_64 with asm.

This could probably be relaxed further thanks to meson's "exe_wrapper",
which is way to specify an emulator or compatibility layer (wine) that
can run the foreign binaries on the build system. Since the meson build
at this point only supports building on Linux I can't test this and I
don't want to write/enable code that cannot even be build tested.

v4: - set condition to build == x86_64 and host == 'x86' and
      build.system == host.system

Signed-off-by: Dylan Baker <dylanx.c.baker at intel.com>
---
 meson.build | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/meson.build b/meson.build
index 049c9a24e4a..23ed42ec0f9 100644
--- a/meson.build
+++ b/meson.build
@@ -542,13 +542,16 @@ endif
 
 # TODO: texture-float (gallium/mesa only)
 
-# TODO: cross-compiling. I don't think this is relavent to meson
-
-# FIXME: enable asm when cross compiler
-# This is doable (autotools does it), but it's not of immediate concern
-if meson.is_cross_build() and host_machine.cpu_family().startswith('x86')
-  message('Cross compiling, disabling x86/x86_64 asm')
-  with_asm = false
+# Building x86 assembly code requires running x86 binaries. It is possible for
+# x86_64 OSes to run x86 binaries, so don't disable asm in those cases
+# TODO: it should be possible to use an exe_wrapper to run the binary during
+# the build. 
+if meson.is_cross_build() 
+  if not (build_machine.cpu_family() == 'x86_64' and host_machine.cpu_family() == 'x86'
+          and build_machine.system() == host_machine.system())
+    message('Cross compiling to x86 from non-x86, disabling asm')
+    with_asm = false
+  endif
 endif
 
 with_asm_arch = ''
-- 
2.15.0