/* ----------------------------------------------------------------------------
- * $Id: Closures.h,v 1.27 2001/08/29 17:24:25 qrczak Exp $
+ * $Id: Closures.h,v 1.35 2003/11/14 14:28:07 stolz Exp $
*
* (c) The GHC Team, 1998-1999
*
The profiling header
-------------------------------------------------------------------------- */
-#ifdef PROFILING
-
-typedef struct {
- CostCentreStack *ccs;
-} StgProfHeader;
-
-#else /* !PROFILING */
-
typedef struct {
- /* empty */
+ CostCentreStack *ccs;
+ union {
+ struct _RetainerSet *rs; // Retainer Set
+ StgWord ldvw; // Lag/Drag/Void Word
+ } hp;
} StgProfHeader;
-#endif /* PROFILING */
-
-/* -----------------------------------------------------------------------------
- The parallel header
- -------------------------------------------------------------------------- */
-
-#ifdef PAR
-
-typedef struct {
- /* StgWord ga; */ /* nope! global addresses are managed via a hash table */
-} StgParHeader;
-
-#else /* !PAR */
-
-typedef struct {
- /* empty */
-} StgParHeader;
-
-#endif /* PAR */
-
/* -----------------------------------------------------------------------------
The GranSim header
-------------------------------------------------------------------------- */
-#if defined(GRAN)
-
typedef struct {
StgWord procs; /* bitmask indicating on which PEs this closure resides */
} StgGranHeader;
-#else /* !GRAN */
-
-typedef struct {
- /* empty */
-} StgGranHeader;
-
-#endif /* GRAN */
-
-/* -----------------------------------------------------------------------------
- The ticky-ticky header
-
- Comment from old Ticky.h:
-
- This is used to record if a closure has been updated but not yet
- entered. It is set when the closure is updated and cleared when
- subsequently entered.
-
- NB: It is {\em not} an ``entry count'', it is an
- ``entries-after-update count.''
-
- The commoning up of @CONST@, @CHARLIKE@ and @INTLIKE@ closures is
- turned off(?) if this is required. This has only been done for 2s
- collection. It is done using a nasty hack which defines the
- @_Evacuate@ and @_Scavenge@ code for @CONST@, @CHARLIKE@ and @INTLIKE@
- info tables to be @_Evacuate_1@ and @_Scavenge_1_0@.
- -------------------------------------------------------------------------- */
-
-#ifdef TICKY_TICKY
-
-typedef struct {
- /* old: W_ updated; */
-} StgTickyHeader;
-
-#else /* !TICKY_TICKY */
-
-typedef struct {
- /* empty */
-} StgTickyHeader;
-
-#endif /* TICKY_TICKY */
-
/* -----------------------------------------------------------------------------
The full fixed-size closure header
#ifdef PROFILING
StgProfHeader prof;
#endif
-#ifdef PAR
- StgParHeader par;
-#endif
#ifdef GRAN
StgGranHeader gran;
#endif
-#ifdef TICKY_TICKY
- StgTickyHeader ticky;
-#endif
} StgHeader;
#define FIXED_HS (sizeof(StgHeader))
typedef struct {
StgHeader header;
- StgWord n_args;
- StgClosure *fun;
+ StgHalfWord arity; /* zero if it is an AP */
+ StgHalfWord n_args;
+ StgClosure *fun; /* really points to a fun */
StgClosure *payload[FLEXIBLE_ARRAY];
} StgPAP;
+// AP closures have the same layout, for convenience
+typedef StgPAP StgAP;
+
typedef struct {
StgHeader header;
- StgWord n_args;
+ StgWord size; // number of words in payload
StgClosure *fun;
- StgClosure *payload[FLEXIBLE_ARRAY];
-} StgAP_UPD;
+ StgClosure *payload[FLEXIBLE_ARRAY]; // contains a chunk of *stack*
+} StgAP_STACK;
typedef struct {
StgHeader header;
StgMutClosure *mut_link;
} StgMutVar;
-typedef struct {
- StgHeader header;
- StgArrWords *instrs; /* a pointer to an ArrWords */
- StgArrWords *literals; /* a pointer to an ArrWords */
- StgMutArrPtrs *ptrs; /* a pointer to a MutArrPtrs */
- StgArrWords *itbls; /* a pointer to an ArrWords */
-} StgBCO;
-
-/*
- A collective typedef for all linkable stack frames i.e.
- StgUpdateFrame, StgSeqFrame, StgCatchFrame
-*/
-typedef struct _StgFrame {
- StgHeader header;
- struct _StgFrame *link;
-} StgFrame;
-
typedef struct _StgUpdateFrame {
StgHeader header;
- struct _StgUpdateFrame *link;
StgClosure *updatee;
} StgUpdateFrame;
typedef struct {
StgHeader header;
- struct _StgUpdateFrame *link;
-} StgSeqFrame;
-
-typedef struct {
- StgHeader header;
- struct _StgUpdateFrame *link;
StgInt exceptions_blocked;
StgClosure *handler;
} StgCatchFrame;
struct _StgWeak *link;
} StgDeadWeak;
+/* Byte code objects. These are fixed size objects with pointers to
+ * four arrays, designed so that a BCO can be easily "re-linked" to
+ * other BCOs, to facilitate GHC's intelligent recompilation. The
+ * array of instructions is static and not re-generated when the BCO
+ * is re-linked, but the other 3 arrays will be regenerated.
+ *
+ * A BCO represents either a function or a stack frame. In each case,
+ * it needs a bitmap to describe to the garbage collector the
+ * pointerhood of its arguments/free variables respectively, and in
+ * the case of a function it also needs an arity. These are stored
+ * directly in the BCO, rather than in the instrs array, for two
+ * reasons:
+ * (a) speed: we need to get at the bitmap info quickly when
+ * the GC is examining APs and PAPs that point to this BCO
+ * (b) a subtle interaction with the compacting GC. In compacting
+ * GC, the info that describes the size/layout of a closure
+ * cannot be in an object more than one level of indirection
+ * away from the current object, because of the order in
+ * which pointers are updated to point to their new locations.
+ */
+
+typedef struct {
+ StgHeader header;
+ StgArrWords *instrs; // a pointer to an ArrWords
+ StgArrWords *literals; // a pointer to an ArrWords
+ StgMutArrPtrs *ptrs; // a pointer to a MutArrPtrs
+ StgArrWords *itbls; // a pointer to an ArrWords
+ StgHalfWord arity; // arity of this BCO
+ StgHalfWord size; // size of this BCO (in words)
+ StgWord bitmap[FLEXIBLE_ARRAY]; // an StgLargeBitmap
+} StgBCO;
+
+#define BCO_BITMAP(bco) ((StgLargeBitmap *)((StgBCO *)(bco))->bitmap)
+#define BCO_BITMAP_SIZE(bco) (BCO_BITMAP(bco)->size)
+#define BCO_BITMAP_BITS(bco) (BCO_BITMAP(bco)->bitmap)
+#define BCO_BITMAP_SIZEW(bco) ((BCO_BITMAP_SIZE(bco) + BITS_IN(StgWord) - 1) \
+ / BITS_IN(StgWord))
+
/* Dynamic stack frames - these have a liveness mask in the object
* itself, rather than in the info table. Useful for generic heap
- * check code.
+ * check code. See StgMacros.h, HEAP_CHK_GEN().
*/
typedef struct {
- const struct _StgInfoTable* info;
- StgWord liveness;
- StgWord ret_addr;
- StgWord payload[FLEXIBLE_ARRAY];
+ const struct _StgInfoTable* info;
+ StgWord liveness;
+ StgWord ret_addr;
+ StgClosure * payload[FLEXIBLE_ARRAY];
} StgRetDyn;
+/* A function return stack frame: used when saving the state for a
+ * garbage collection at a function entry point. The function
+ * arguments are on the stack, and we also save the function (its
+ * info table describes the pointerhood of the arguments).
+ *
+ * The stack frame size is also cached in the frame for convenience.
+ */
+typedef struct {
+ const struct _StgInfoTable* info;
+ StgWord size;
+ StgClosure * fun;
+ StgClosure * payload[FLEXIBLE_ARRAY];
+} StgRetFun;
+
/* Concurrent communication objects */
typedef struct {
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