glsl/sso: Add parser and AST-to-HIR support for separate shader object layouts

GL_ARB_separate_shader_objects adds the ability to specify location
layouts for interstage inputs and outputs.

In addition, this extension makes 'in' and 'out' generally available for
shader inputs and outputs.  This mimics the behavior of
GL_ARB_explicit_attrib_location.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

src/glsl/ast_to_hir.cpp

@@ -2123,11 +2123,16 @@ validate_explicit_location(const struct ast_type_qualifier *qual,
 {
    bool fail = false;
 
-   /* In the vertex shader only shader inputs can be given explicit
-    * locations.
+   /* Between GL_ARB_explicit_attrib_location an
+    * GL_ARB_separate_shader_objects, the inputs and outputs of any shader
+    * stage can be assigned explicit locations.  The checking here associates
+    * the correct extension with the correct stage's input / output:
     *
-    * In the fragment shader only shader outputs can be given explicit
-    * locations.
+    *                     input            output
+    *                     -----            ------
+    * vertex              explicit_loc     sso
+    * geometry            sso              sso
+    * fragment            sso              explicit_loc
     */
    switch (state->stage) {
    case MESA_SHADER_VERTEX:
@@ -2138,16 +2143,35 @@ validate_explicit_location(const struct ast_type_qualifier *qual,
          break;
       }
 
+      if (var->data.mode == ir_var_shader_out) {
+         if (!state->check_separate_shader_objects_allowed(loc, var))
+            return;
+
+         break;
+      }
+
       fail = true;
       break;
 
    case MESA_SHADER_GEOMETRY:
-      _mesa_glsl_error(loc, state,
-                       "geometry shader variables cannot be given "
-                       "explicit locations");
-      return;
+      if (var->data.mode == ir_var_shader_in || var->data.mode == ir_var_shader_out) {
+         if (!state->check_separate_shader_objects_allowed(loc, var))
+            return;
+
+         break;
+      }
+
+      fail = true;
+      break;
 
    case MESA_SHADER_FRAGMENT:
+      if (var->data.mode == ir_var_shader_in) {
+         if (!state->check_separate_shader_objects_allowed(loc, var))
+            return;
+
+         break;
+      }
+
       if (var->data.mode == ir_var_shader_out) {
          if (!state->check_explicit_attrib_location_allowed(loc, var))
             return;
@@ -2181,9 +2205,23 @@ validate_explicit_location(const struct ast_type_qualifier *qual,
        * ensures that negative values stay negative.
        */
       if (qual->location >= 0) {
-         var->data.location = (state->stage == MESA_SHADER_VERTEX)
-            ? (qual->location + VERT_ATTRIB_GENERIC0)
-            : (qual->location + FRAG_RESULT_DATA0);
+         switch (state->stage) {
+         case MESA_SHADER_VERTEX:
+            var->data.location = (var->data.mode == ir_var_shader_in)
+               ? (qual->location + VERT_ATTRIB_GENERIC0)
+               : (qual->location + VARYING_SLOT_VAR0);
+            break;
+
+         case MESA_SHADER_GEOMETRY:
+            var->data.location = qual->location + VARYING_SLOT_VAR0;
+            break;
+
+         case MESA_SHADER_FRAGMENT:
+            var->data.location = (var->data.mode == ir_var_shader_out)
+               ? (qual->location + FRAG_RESULT_DATA0)
+               : (qual->location + VARYING_SLOT_VAR0);
+            break;
+         }
       } else {
          var->data.location = qual->location;
       }
@@ -2207,8 +2245,6 @@ validate_explicit_location(const struct ast_type_qualifier *qual,
          }
       }
    }
-
-   return;
 }
 
 static void
@@ -3147,6 +3183,7 @@ ast_declarator_list::hir(exec_list *instructions,
        */
       if (!state->is_version(130, 300)
 	  && !state->has_explicit_attrib_location()
+	  && !state->has_separate_shader_objects()
 	  && !state->ARB_fragment_coord_conventions_enable) {
 	 if (this->type->qualifier.flags.q.out) {
 	    _mesa_glsl_error(& loc, state,

src/glsl/glcpp/glcpp-parse.y

@@ -2134,6 +2134,9 @@ _glcpp_parser_handle_version_declaration(glcpp_parser_t *parser, intmax_t versio
 	      if (extensions->ARB_texture_gather)
 	         add_builtin_define(parser, "GL_ARB_texture_gather", 1);
 
+              if (extensions->ARB_separate_shader_objects)
+                 add_builtin_define(parser, "GL_ARB_separate_shader_objects", 1);
+
 	      if (extensions->ARB_shader_atomic_counters)
 	         add_builtin_define(parser, "GL_ARB_shader_atomic_counters", 1);
 

src/glsl/glsl_lexer.ll

@@ -392,6 +392,7 @@ layout		{
 		      || yyextra->AMD_conservative_depth_enable
 		      || yyextra->ARB_conservative_depth_enable
 		      || yyextra->ARB_explicit_attrib_location_enable
+                      || yyextra->has_separate_shader_objects()
 		      || yyextra->ARB_uniform_buffer_object_enable
 		      || yyextra->ARB_fragment_coord_conventions_enable
                       || yyextra->ARB_shading_language_420pack_enable

src/glsl/glsl_parser_extras.h

@@ -135,6 +135,23 @@ struct _mesa_glsl_parse_state {
       return true;
    }
 
+   bool check_separate_shader_objects_allowed(YYLTYPE *locp,
+                                              const ir_variable *var)
+   {
+      if (!this->has_separate_shader_objects()) {
+         const char *const requirement = this->es_shader
+            ? "GL_EXT_separate_shader_objects (not supported by this "
+              "implementation)"
+            : "GL_ARB_separate_shader_objects extension or GLSL 420";
+
+         _mesa_glsl_error(locp, this, "%s explicit location requires %s",
+                          mode_string(var), requirement);
+         return false;
+      }
+
+      return true;
+   }
+
    bool has_explicit_attrib_location() const
    {
       return ARB_explicit_attrib_location_enable || is_version(330, 300);