173 lines
4.7 KiB
C
173 lines
4.7 KiB
C
/*************************************************************************
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* *
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* YAP Prolog *
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* *
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* Yap Prolog was developed at NCCUP - Universidade do Porto *
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* *
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* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
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* *
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**************************************************************************
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* *
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* File: heapgc.c *
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* Last rev: *
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* mods: *
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* comments: Header for Global Stack garbage collector *
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* *
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*************************************************************************/
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/* macros used by garbage collection */
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#if TAG_64BITS
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#define MaskAdr (~((CELL)0x7))
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#endif
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/* return pointer from object pointed to by ptr (remove tag & mark) */
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#ifdef TAGS_FAST_OPS
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#define GET_NEXT(val) ((CELL *)(IsVarTerm((val)) ? \
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(val) & MaskAdr : \
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( IsPairTerm((val)) ? \
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Unsigned(RepPair((val))) & MaskAdr : \
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( IsApplTerm((val)) ? \
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Unsigned(RepAppl((val))) & MaskAdr : \
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(val) & MaskAdr \
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) \
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) \
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) \
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)
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#else
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#ifdef TAG_LOW_BITS_32
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#define GET_NEXT(val) ((CELL *) ((val) & ~LowTagBits))
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#else
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#define GET_NEXT(val) ((CELL *) ((val) & MaskAdr))
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#endif
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#endif
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/* is ptr a pointer to the heap? */
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#define ONHEAP(ptr) (CellPtr(ptr) >= H0 && CellPtr(ptr) < H)
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/* is ptr a pointer to code space? */
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#if USE_SYSTEM_MALLOC
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#define ONCODE(ptr) (Addr(ptr) < LOCAL_GlobalBase || Addr(ptr) > LOCAL_TrailTop)
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#else
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#define ONCODE(ptr) (Addr(ptr) < HeapTop && Addr(ptr) >= Yap_HeapBase)
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#endif
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/* is val pointing to something bound to the heap? */
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#define GCIsPrimitiveTerm(X) (/* not really needed !IsVarTerm(X) && */ IsAtomOrIntTerm(X))
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/* Does X point to an object in the heap */
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#define HEAP_PTR(val) (!GCIsPrimitiveTerm(val) && ONHEAP(GET_NEXT(val)))
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/*
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Heap_trail_entry must be very careful. We are looking at a valid
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trail entry if: it was between H0 and HB or between B and LCLO
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(that is, if it was covered by choicepoints at the time), and if it
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was a heap pointer.
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We can join the two conditions: (H0 =< val < HB || ((B < val < LCL0)
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&& H0 <= *DETAG(val) < H))
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*/
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#define HEAP_TRAIL_ENTRY(val) ((IsVarTerm(val)) && \
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((H0 <= CellPtr(val) && CellPtr(val)\
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< cp_H) || \
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(CellPtr(B) < CellPtr(val) && CellPtr(val) <= \
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LCL0 && HEAP_PTR(val))))
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#define MARK_BIT ((char)1)
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#define RMARK_BIT ((char)2)
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#define mcell(X) LOCAL_bp[(X)-(CELL *)LOCAL_GlobalBase]
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#define MARKED_PTR(P) MARKED_PTR__(P PASS_REGS)
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#define UNMARKED_MARK(P, BP) UNMARKED_MARK__(P, BP PASS_REGS)
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#define MARK(P) MARK__(P PASS_REGS)
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#define UNMARK(P) UNMARK__(P PASS_REGS)
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#define RMARK(P) RMARK__(P PASS_REGS)
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#define RMARKED(P) RMARKED__(P PASS_REGS)
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#define UNRMARK(P) UNRMARK__(P PASS_REGS)
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static inline Int
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MARKED_PTR__(CELL* ptr USES_REGS)
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{
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return mcell(ptr) & MARK_BIT;
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}
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static inline Int
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UNMARKED_MARK__(CELL* ptr, char *bp USES_REGS)
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{
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Int pos = ptr - (CELL *)LOCAL_GlobalBase;
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char t = bp[pos];
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if (t & MARK_BIT) {
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return TRUE;
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}
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bp[pos] = t | MARK_BIT;
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return FALSE;
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}
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static inline void
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MARK__(CELL* ptr USES_REGS)
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{
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mcell(ptr) = mcell(ptr) | MARK_BIT;
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}
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static inline void
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UNMARK__(CELL* ptr USES_REGS)
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{
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mcell(ptr) = mcell(ptr) & ~MARK_BIT;
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}
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/* not really that useful */
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#define MAY_UNMARK(X)
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#define UNMARK_CELL(X) (X)
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static inline void
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RMARK__(CELL* ptr USES_REGS)
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{
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mcell(ptr) = mcell(ptr) | RMARK_BIT;
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}
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static inline void
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UNRMARK__(CELL* ptr USES_REGS)
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{
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mcell(ptr) = mcell(ptr) & ~RMARK_BIT;
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}
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static inline int
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RMARKED__(CELL* ptr USES_REGS)
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{
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return mcell(ptr) & RMARK_BIT;
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}
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/* is the object pointed to by ptr marked as in a relocation chain? */
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#if LONG_ADDRESSES
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#ifdef TAG_LOW_BITS_32
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#define TAG(X) ((X) & LowTagBits)
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#else
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#ifdef TAG_64BITS
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#define TAG(X) ((X) & MKTAG(0x0,0x7))
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#else
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#define TAG(X) ((X) & 0x80000003L)
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#endif
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#endif
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#else
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#define TAG(X) ((X) & 0x98000000L)
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#endif
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typedef CELL *CELL_PTR;
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#define ENVSIZE(E) EnvSize(((CELL *)E)[E_CP])
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void STD_PROTO(Yap_mark_variable, (CELL *));
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void STD_PROTO(Yap_mark_external_reference, (CELL *));
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void STD_PROTO(Yap_inc_mark_variable, (void));
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