glsl: Move layout(location) checks to AST-to-HIR conversion

This will simplify the addition of layout(location) qualifiers for
separate shader objects.  This was validated with new piglit tests
arb_explicit_attrib_location/1.30/compiler/not-enabled-01.vert and
arb_explicit_attrib_location/1.30/compiler/not-enabled-02.vert.

v2: Refactor error checking to check_explicit_attrib_location_allowed
and eliminate the gotos.  Suggested by Paul.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Paul Berry <stereotype441@gmail.com>

src/glsl/ast_to_hir.cpp

@@ -2063,6 +2063,9 @@ validate_explicit_location(const struct ast_type_qualifier *qual,
    switch (state->target) {
    case vertex_shader:
       if (var->mode == ir_var_shader_in) {
+         if (!state->check_explicit_attrib_location_allowed(loc, var))
+            return;
+
          break;
       }
 
@@ -2077,6 +2080,9 @@ validate_explicit_location(const struct ast_type_qualifier *qual,
 
    case fragment_shader:
       if (var->mode == ir_var_shader_out) {
+         if (!state->check_explicit_attrib_location_allowed(loc, var))
+            return;
+
          break;
       }
 
@@ -2126,6 +2132,8 @@ validate_explicit_location(const struct ast_type_qualifier *qual,
          }
       }
    }
+
+   return;
 }
 
 static void

src/glsl/glsl_parser.yy

@@ -1302,29 +1302,25 @@ layout_qualifier_id:
    {
       memset(& $$, 0, sizeof($$));
 
-      if (state->has_explicit_attrib_location()) {
-         if (match_layout_qualifier("location", $1, state) == 0) {
-            $$.flags.q.explicit_location = 1;
+      if (match_layout_qualifier("location", $1, state) == 0) {
+         $$.flags.q.explicit_location = 1;
 
-            if ($3 >= 0) {
-               $$.location = $3;
-            } else {
-               _mesa_glsl_error(& @3, state,
-                                "invalid location %d specified", $3);
-               YYERROR;
-            }
+         if ($3 >= 0) {
+            $$.location = $3;
+         } else {
+             _mesa_glsl_error(& @3, state, "invalid location %d specified", $3);
+             YYERROR;
          }
+      }
 
-         if (match_layout_qualifier("index", $1, state) == 0) {
-            $$.flags.q.explicit_index = 1;
+      if (match_layout_qualifier("index", $1, state) == 0) {
+         $$.flags.q.explicit_index = 1;
 
-            if ($3 >= 0) {
-               $$.index = $3;
-            } else {
-               _mesa_glsl_error(& @3, state,
-                                "invalid index %d specified", $3);
-               YYERROR;
-            }
+         if ($3 >= 0) {
+            $$.index = $3;
+         } else {
+            _mesa_glsl_error(& @3, state, "invalid index %d specified", $3);
+            YYERROR;
          }
       }
 

src/glsl/glsl_parser_extras.h

@@ -69,6 +69,10 @@ typedef struct YYLTYPE {
 # define YYLTYPE_IS_DECLARED 1
 # define YYLTYPE_IS_TRIVIAL 1
 
+extern void _mesa_glsl_error(YYLTYPE *locp, _mesa_glsl_parse_state *state,
+			     const char *fmt, ...);
+
+
 struct _mesa_glsl_parse_state {
    _mesa_glsl_parse_state(struct gl_context *_ctx, GLenum target,
 			  void *mem_ctx);
@@ -121,6 +125,22 @@ struct _mesa_glsl_parse_state {
       return check_version(130, 300, locp, "bit-wise operations are forbidden");
    }
 
+   bool check_explicit_attrib_location_allowed(YYLTYPE *locp,
+                                               const ir_variable *var)
+   {
+      if (!this->has_explicit_attrib_location()) {
+         const char *const requirement = this->es_shader
+            ? "GLSL ES 300"
+            : "GL_ARB_explicit_attrib_location extension or GLSL 330";
+
+         _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);
@@ -372,9 +392,6 @@ do {								\
    (Current).source = 0;					\
 } while (0)
 
-extern void _mesa_glsl_error(YYLTYPE *locp, _mesa_glsl_parse_state *state,
-			     const char *fmt, ...);
-
 /**
  * Emit a warning to the shader log
  *