/* If a runtime function needs to call another function which potentially allocates memory, it must store any local variable references to Factor objects on the root stack */ /* GC locals: stores addresses of pointers to objects. The GC updates these pointers, so you can do REGISTER_ROOT(some_local); ... allocate memory ... foo(some_local); ... UNREGISTER_ROOT(some_local); */ F_SEGMENT *gc_locals_region; CELL gc_locals; DEFPUSHPOP(gc_local_,gc_locals) #define REGISTER_ROOT(obj) gc_local_push((CELL)&obj) #define UNREGISTER_ROOT(obj) \ { \ if(gc_local_pop() != (CELL)&obj) \ critical_error("Mismatched REGISTER_ROOT/UNREGISTER_ROOT",0); \ } /* Extra roots: stores pointers to objects in the heap. Requires extra work (you have to unregister before accessing the object) but more flexible. */ F_SEGMENT *extra_roots_region; CELL extra_roots; DEFPUSHPOP(root_,extra_roots) #define REGISTER_UNTAGGED(obj) root_push(obj ? tag_object(obj) : 0) #define UNREGISTER_UNTAGGED(obj) obj = untag_object(root_pop()) /* We ignore strings which point outside the data heap, but we might be given a char* which points inside the data heap, in which case it is a root, for example if we call unbox_char_string() the result is placed in a byte array */ INLINE bool root_push_alien(const void *ptr) { if(in_data_heap_p((CELL)ptr)) { F_BYTE_ARRAY *objptr = ((F_BYTE_ARRAY *)ptr) - 1; if(objptr->header == tag_header(BYTE_ARRAY_TYPE)) { root_push(tag_object(objptr)); return true; } } return false; } #define REGISTER_C_STRING(obj) \ bool obj##_root = root_push_alien(obj) #define UNREGISTER_C_STRING(obj) \ if(obj##_root) obj = alien_offset(root_pop()) #define REGISTER_BIGNUM(obj) if(obj) root_push(tag_bignum(obj)) #define UNREGISTER_BIGNUM(obj) if(obj) obj = (untag_object(root_pop()))