glsl: do not lookup struct types by typename

This changes the logic during the conversion of the declaration list

   struct S {
      ...
   } v;

from AST to IR, but should not change the end result.

When assigning the type of v, instead of looking `S' up in the symbol
table, we read the type from the member variable of ast_struct_specifier.

This change is necessary for the subsequent change to how anonymous types
are handled.

v2: remove a type override when redefining a structure; should be
    the same type in that case anyway

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>

src/compiler/glsl/ast.h

@@ -844,6 +844,7 @@ public:
    /* List of ast_declarator_list * */
    exec_list declarations;
    bool is_declaration;
+   const glsl_type *type;
 };
 
 

src/compiler/glsl/ast_to_hir.cpp

@@ -2359,6 +2359,9 @@ ast_type_specifier::glsl_type(const char **name,
 {
    const struct glsl_type *type;
 
+   if (structure)
+      type = structure->type;
+   else
       type = state->symbols->get_type(this->type_name);
    *name = this->type_name;
 
@@ -7504,13 +7507,12 @@ ast_struct_specifier::hir(exec_list *instructions,
 
    validate_identifier(this->name, loc, state);
 
-   const glsl_type *t =
-      glsl_type::get_record_instance(fields, decl_count, this->name);
+   type = glsl_type::get_record_instance(fields, decl_count, this->name);
 
-   if (!state->symbols->add_type(name, t)) {
+   if (!state->symbols->add_type(name, type)) {
       const glsl_type *match = state->symbols->get_type(name);
       /* allow struct matching for desktop GL - older UE4 does this */
-      if (match != NULL && state->is_version(130, 0) && match->record_compare(t, false))
+      if (match != NULL && state->is_version(130, 0) && match->record_compare(type, false))
          _mesa_glsl_warning(& loc, state, "struct `%s' previously defined", name);
       else
          _mesa_glsl_error(& loc, state, "struct `%s' previously defined", name);
@@ -7519,7 +7521,7 @@ ast_struct_specifier::hir(exec_list *instructions,
                                      const glsl_type *,
                                      state->num_user_structures + 1);
       if (s != NULL) {
-         s[state->num_user_structures] = t;
+         s[state->num_user_structures] = type;
          state->user_structures = s;
          state->num_user_structures++;
       }

src/compiler/glsl/glsl_parser_extras.cpp

@@ -1690,6 +1690,7 @@ ast_struct_specifier::ast_struct_specifier(void *lin_ctx, const char *identifier
    this->declarations.push_degenerate_list_at_head(&declarator_list->link);
    is_declaration = true;
    layout = NULL;
+   type = NULL;
 }
 
 void ast_subroutine_list::print(void) const