— Target Hook: void * TARGET_GET_PCH_VALIDITY (size_t * sz)

Define this hook if your target needs to check a different collection of flags than the default, which is every flag defined by TARGET_SWITCHES and TARGET_OPTIONS. It should return some data which will be saved in the PCH file and presented to TARGET_PCH_VALID_P later; it should set SZ to the size of the data.

— Target Hook: const char * TARGET_PCH_VALID_P (const void * data, size_t sz)

Define this hook if your target needs to check a different collection of flags than the default, which is every flag defined by TARGET_SWITCHES and TARGET_OPTIONS. It is given data which came from TARGET_GET_PCH_VALIDITY (in this version of this compiler, so there is no need for extensive validity checking). It returns NULL if it is safe to load a PCH file with this data, or a suitable error message if not. The error message will be presented to the user, so it should be localized.