ureg: add a mechanism to get the built tokens rather than a full shader

Previously ureg would always call the driver's create-shader function.  This
allows the caller the opportunity to hold onto the tokens if it needs to
reuse them, eg. to create an internal draw shader.

src/gallium/auxiliary/tgsi/tgsi_ureg.c

@@ -978,6 +978,25 @@ void *ureg_create_shader( struct ureg_program *ureg,
 }
 
 
+const struct tgsi_token *ureg_get_tokens( struct ureg_program *ureg,
+                                          unsigned *nr_tokens )
+{
+   const struct tgsi_token *tokens;
+
+   ureg_finalize(ureg);
+
+   tokens = &ureg->domain[DOMAIN_DECL].tokens[0].token;
+
+   if (nr_tokens) 
+      *nr_tokens = ureg->domain[DOMAIN_DECL].size;
+
+   ureg->domain[DOMAIN_DECL].tokens = 0;
+   ureg->domain[DOMAIN_DECL].size = 0;
+   ureg->domain[DOMAIN_DECL].order = 0;
+   ureg->domain[DOMAIN_DECL].count = 0;
+
+   return tokens;
+}
 
 
 struct ureg_program *ureg_create( unsigned processor )

src/gallium/auxiliary/tgsi/tgsi_ureg.h

@@ -82,10 +82,21 @@ ureg_create( unsigned processor );
 const struct tgsi_token *
 ureg_finalize( struct ureg_program * );
 
+/* Create and return a shader:
+ */
 void *
 ureg_create_shader( struct ureg_program *,
                     struct pipe_context *pipe );
 
+
+/* Alternately, return the built token stream and hand ownership of
+ * that memory to the caller:
+ */
+const struct tgsi_token *
+ureg_get_tokens( struct ureg_program *ureg,
+                 unsigned *nr_tokens );
+
+
 void 
 ureg_destroy( struct ureg_program * );