i965: Add a function to translate MESA_SHADER_* into DEBUG_* enums.

When compiling, we have a gl_shader_stage (MESA_SHADER_*) enum, and want
to know whether debugging is enabled for that stage.  This allows us to
easily translate it into the corresponding debug flag.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kristian Høgsberg <krh@bitplanet.net>
Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>

src/mesa/drivers/dri/i965/intel_debug.c

@@ -72,6 +72,19 @@ static const struct dri_debug_control debug_control[] = {
    { NULL,    0 }
 };
 
+uint64_t
+intel_debug_flag_for_shader_stage(gl_shader_stage stage)
+{
+   int flags[] = {
+      [MESA_SHADER_VERTEX] = DEBUG_VS,
+      [MESA_SHADER_GEOMETRY] = DEBUG_GS,
+      [MESA_SHADER_FRAGMENT] = DEBUG_WM,
+      [MESA_SHADER_COMPUTE] = 0, /* no debug flag yet */
+   };
+   STATIC_ASSERT(MESA_SHADER_STAGES == 4);
+   return flags[stage];
+}
+
 void
 brw_process_intel_debug_variable(struct brw_context *brw)
 {