glsl2: talloc the glsl_struct_field[] we use to look up structure types.

Since the types are singletons across the lifetime of the compiler,
repeatedly compiling a program with the same structure type defined
would drop a copy of the array on the floor per compile.

This is a bit tricky because the static GLSL types are not called with
the talloc-based new, so we have to use the global type context, which
may not be initialized yet.

src/glsl/ast_to_hir.cpp

@@ -2471,8 +2471,8 @@ ast_struct_specifier::hir(exec_list *instructions,
     * the types to HIR.  This ensures that structure definitions embedded in
     * other structure definitions are processed.
     */
-   glsl_struct_field *const fields = (glsl_struct_field *)
-      malloc(sizeof(*fields) * decl_count);
+   glsl_struct_field *const fields = talloc_array(state, glsl_struct_field,
+						  decl_count);
 
    unsigned i = 0;
    foreach_list_typed (ast_declarator_list, decl_list, link,

src/glsl/glsl_types.cpp

@@ -75,7 +75,20 @@ glsl_type::glsl_type(const glsl_struct_field *fields, unsigned num_fields,
    name(name),
    length(num_fields)
 {
-   this->fields.structure = fields;
+   unsigned int i;
+
+   if (glsl_type::ctx == NULL) {
+      glsl_type::ctx = talloc_init("glsl_type");
+      assert(glsl_type::ctx != NULL);
+   }
+
+   this->fields.structure = talloc_array(glsl_type::ctx,
+					 glsl_struct_field, length);
+   for (i = 0; i < length; i++) {
+      this->fields.structure[i].type = fields[i].type;
+      this->fields.structure[i].name = talloc_strdup(this->fields.structure,
+						     fields[i].name);
+   }
 }
 
 static void

src/glsl/glsl_types.h

@@ -136,7 +136,7 @@ struct glsl_type {
    union {
       const struct glsl_type *array;            /**< Type of array elements. */
       const struct glsl_type *parameters;       /**< Parameters to function. */
-      const struct glsl_struct_field *structure;/**< List of struct fields. */
+      struct glsl_struct_field *structure;      /**< List of struct fields. */
    } fields;