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