factor/vm/local_roots.hpp

55 lines
1.2 KiB
C++

namespace factor
{
/* If a runtime function needs to call another function which potentially
allocates memory, it must wrap any local variable references to Factor
objects in gc_root instances */
extern segment *gc_locals_region;
extern cell gc_locals;
DEFPUSHPOP(gc_local_,gc_locals)
template <typename T>
struct gc_root : public tagged<T>
{
void push() { check_tagged_pointer(tagged<T>::value()); gc_local_push((cell)this); }
explicit gc_root(cell value_) : tagged<T>(value_) { push(); }
explicit gc_root(T *value_) : tagged<T>(value_) { push(); }
const gc_root<T>& operator=(const T *x) { tagged<T>::operator=(x); return *this; }
const gc_root<T>& operator=(const cell &x) { tagged<T>::operator=(x); return *this; }
~gc_root() {
#ifdef FACTOR_DEBUG
cell old = gc_local_pop();
assert(old == (cell)this);
#else
gc_local_pop();
#endif
}
};
/* A similar hack for the bignum implementation */
extern segment *gc_bignums_region;
extern cell gc_bignums;
DEFPUSHPOP(gc_bignum_,gc_bignums)
struct gc_bignum
{
bignum **addr;
gc_bignum(bignum **addr_) : addr(addr_) {
if(*addr_)
check_data_pointer(*addr_);
gc_bignum_push((cell)addr);
}
~gc_bignum() { assert((cell)addr == gc_bignum_pop()); }
};
#define GC_BIGNUM(x) gc_bignum x##__gc_root(&x)
}