/* ----------------------------------------------------------------------------
- * $Id: InfoTables.h,v 1.21 2001/03/22 03:51:09 hwloidl Exp $
+ * $Id: InfoTables.h,v 1.31 2003/11/14 09:27:00 stolz Exp $
*
- * (c) The GHC Team, 1998-1999
+ * (c) The GHC Team, 1998-2002
*
* Info Tables
*
Profiling info
-------------------------------------------------------------------------- */
-#ifdef PROFILING
-
typedef struct {
char *closure_type;
char *closure_desc;
} StgProfInfo;
-#else /* !PROFILING */
-
-typedef struct {
- /* empty */
-} StgProfInfo;
-
-#endif /* PROFILING */
-
/* -----------------------------------------------------------------------------
Parallelism info
-------------------------------------------------------------------------- */
StgInfoTable *rbh_infoptr; /* infoptr to the RBH */
} StgParInfo;
-#else /* !PAR */
-
-typedef struct {
- /* empty */
-} StgParInfo;
-
-#endif /* PAR */
+#endif /* 0 */
/*
Copied from ghc-0.29; ToDo: check this code -- HWL
#endif
/* -----------------------------------------------------------------------------
+ Ticky info
+ -------------------------------------------------------------------------- */
+
+#if defined(SUPPORTS_EMPTY_STRUCTS)
+typedef struct {
+ /* empty */
+} StgTickyInfo;
+#endif
+
+/* -----------------------------------------------------------------------------
Debugging info
-------------------------------------------------------------------------- */
#else /* !DEBUG_CLOSURE */
-typedef struct {
+# if defined(SUPPORTS_EMPTY_STRUCTS)
+typedef struct StgDebugInfo {
/* empty */
} StgDebugInfo;
+# endif
#endif /* DEBUG_CLOSURE */
+/* -----------------------------------------------------------------------------
+ Closure flags
+ -------------------------------------------------------------------------- */
+
/* The type flags provide quick access to certain properties of a closure. */
#define _HNF (1<<0) /* head normal form? */
#define ip_IND(ip) ( ipFlags(ip) & _IND)
/* -----------------------------------------------------------------------------
- Info Tables
+ Bitmaps
+
+ These are used to describe the pointerhood of a sequence of words
+ (usually on the stack) to the garbage collector. The two primary
+ uses are for stack frames, and functions (where we need to describe
+ the layout of a PAP to the GC).
-------------------------------------------------------------------------- */
-/* A large bitmap. Small 32-bit ones live in the info table, but sometimes
- * 32 bits isn't enough and we have to generate a larger one. (sizes
- * differ for 64-bit machines.
- */
+/*
+ Small bitmaps: for a small bitmap, we store the size and bitmap in
+ the same word, using the following macros. If the bitmap doesn't
+ fit in a single word, we use a pointer to an StgLargeBitmap below.
+*/
+#define MK_SMALL_BITMAP(size,bits) (((bits)<<BITMAP_BITS_SHIFT) | (size))
+
+#define BITMAP_SIZE(bitmap) ((bitmap) & BITMAP_SIZE_MASK)
+#define BITMAP_BITS(bitmap) ((bitmap) >> BITMAP_BITS_SHIFT)
+/*
+ A large bitmap.
+*/
typedef struct {
StgWord size;
- StgWord bitmap[0];
+ StgWord bitmap[FLEXIBLE_ARRAY];
} StgLargeBitmap;
-/*
- * Stuff describing the closure layout. Well, actually, it might
- * contain the selector index for a THUNK_SELECTOR. If we're on a
- * 64-bit architecture then we can enlarge some of these fields, since
- * the union contains a pointer field.
- */
+/* -----------------------------------------------------------------------------
+ SRTs (Static Reference Tables)
+ These tables are used to keep track of the static objects referred
+ to by the code for a closure or stack frame, so that we can follow
+ static data references from code and thus accurately
+ garbage-collect CAFs.
+ -------------------------------------------------------------------------- */
+
+/* An SRT is just an array of closure pointers: */
+typedef StgClosure* StgSRT[];
+
+/* Each info table refers to some subset of the closure pointers in an
+ SRT. It does this using a pair of an StgSRT pointer and a
+ half-word bitmap. If the half-word bitmap isn't large enough, then
+ we fall back to a large SRT, including an unbounded bitmap. If the
+ half-word bitmap is set to all ones (0xffff), then the StgSRT
+ pointer instead points to an StgLargeSRT: */
+typedef struct StgLargeSRT_ {
+ StgSRT *srt;
+ StgLargeBitmap l;
+} StgLargeSRT;
+
+/* ----------------------------------------------------------------------------
+ Info Tables
+ ------------------------------------------------------------------------- */
+
+/*
+ Stuff describing the closure layout. Well, actually, it might
+ contain the selector index for a THUNK_SELECTOR. This union is one
+ word long.
+*/
typedef union {
- struct {
-#if SIZEOF_VOID_P == 8
- StgWord32 ptrs; /* number of pointers */
- StgWord32 nptrs; /* number of non-pointers */
-#else
- StgWord16 ptrs; /* number of pointers */
- StgWord16 nptrs; /* number of non-pointers */
-#endif
- } payload;
+ struct { /* Heap closure payload layout: */
+ StgHalfWord ptrs; /* number of pointers */
+ StgHalfWord nptrs; /* number of non-pointers */
+ } payload;
+
+ StgWord bitmap; /* word-sized bit pattern describing */
+ /* a stack frame: see below */
+
+ StgLargeBitmap* large_bitmap; /* pointer to large bitmap structure */
+
+ StgWord selector_offset; /* used in THUNK_SELECTORs */
- StgWord bitmap; /* bit pattern, 1 = pointer, 0 = non-pointer */
- StgWord selector_offset; /* used in THUNK_SELECTORs */
- StgLargeBitmap* large_bitmap; /* pointer to large bitmap structure */
-
} StgClosureInfo;
+
/*
- * Info tables. All info tables are the same type, to simplify code
- * generation. However, the mangler removes any unused SRT fields
- * from the asm to save space (convention: if srt_len is zero, or the
- * type is a CONSTR_ type, then the SRT field isn't present.
- */
+ The "standard" part of an info table. Every info table has this bit.
+*/
+typedef struct _StgInfoTable {
-typedef StgClosure* StgSRT[];
+#ifndef TABLES_NEXT_TO_CODE
+ StgFunPtr entry; // pointer to the entry code
+#endif
-typedef struct _StgInfoTable {
- StgSRT *srt; /* pointer to the SRT table */
#if defined(PAR) || defined(GRAN)
struct _StgInfoTable *rbh_infoptr;
#endif
#ifdef PROFILING
StgProfInfo prof;
#endif
-#ifdef DEBUG_CLOSURE
- StgDebugInfo debug;
+#ifdef TICKY
+ MAYBE_EMPTY_STRUCT(StgTickyInfo,ticky)
#endif
- StgClosureInfo layout; /* closure layout info (pointer-sized) */
-#if SIZEOF_VOID_P == 8
- StgWord32 type; /* } These 2 elements fit into 64 bits */
- StgWord32 srt_len; /* } */
-#else
- StgWord type : 16; /* } These 2 elements fit into 32 bits */
- StgWord srt_len : 16; /* } */
+#ifdef DEBUG_CLOSURE
+ MAYBE_EMPTY_STRUCT(StgDebugInfo,debug)
#endif
+
+ StgClosureInfo layout; /* closure layout info (one word) */
+
+ StgHalfWord type; /* closure type */
+ StgHalfWord srt_bitmap; /* number of entries in SRT (or constructor tag) */
+
#ifdef TABLES_NEXT_TO_CODE
- StgCode code[0];
-#else
- StgFunPtr entry;
- StgFunPtr vector[0];
+ StgCode code[FLEXIBLE_ARRAY];
#endif
} StgInfoTable;
-/* Info tables are read-only, therefore we uniformly declare them with
- * C's const attribute. This isn't just a nice thing to do: it's
- * necessary because the garbage collector has to distinguish between
- * closure pointers and info table pointers when traversing the
- * stack. We distinguish the two by checking whether the pointer is
- * into text-space or not.
- */
-
-#define INFO_TBL_CONST const
+
+/* -----------------------------------------------------------------------------
+ Function info tables
+
+ This is the general form of function info tables. The compiler
+ will omit some of the fields in common cases:
+
+ - If fun_type is not ARG_GEN or ARG_GEN_BIG, then the slow_apply
+ and bitmap fields may be left out (they are at the end, so omitting
+ them doesn't affect the layout).
+
+ - If srt_bitmap (in the std info table part) is zero, then the srt
+ field may be omitted. This only applies if the slow_apply and
+ bitmap fields have also been omitted.
+ -------------------------------------------------------------------------- */
+
+typedef struct _StgFunInfoTable {
+#if defined(TABLES_NEXT_TO_CODE)
+ StgFun *slow_apply; /* apply to args on the stack */
+ StgWord bitmap; /* arg ptr/nonptr bitmap */
+ StgSRT *srt; /* pointer to the SRT table */
+ StgHalfWord fun_type; /* function type */
+ StgHalfWord arity; /* function arity */
+ StgInfoTable i;
+#else
+ StgInfoTable i;
+ StgHalfWord fun_type; /* function type */
+ StgHalfWord arity; /* function arity */
+ StgSRT *srt; /* pointer to the SRT table */
+ StgWord bitmap; /* arg ptr/nonptr bitmap */
+ StgFun *slow_apply; /* apply to args on the stack */
+#endif
+} StgFunInfoTable;
+
+/* -----------------------------------------------------------------------------
+ Return info tables
+ -------------------------------------------------------------------------- */
+
+/* When info tables are laid out backwards, we can omit the SRT
+ pointer iff srt_bitmap is zero. */
+
+typedef struct _StgRetInfoTable {
+#if !defined(TABLES_NEXT_TO_CODE)
+ StgInfoTable i;
+#endif
+ StgSRT *srt; /* pointer to the SRT table */
+#if defined(TABLES_NEXT_TO_CODE)
+ StgInfoTable i;
+#endif
+#if !defined(TABLES_NEXT_TO_CODE)
+ StgFunPtr vector[FLEXIBLE_ARRAY];
+#endif
+} StgRetInfoTable;
+
+/* -----------------------------------------------------------------------------
+ Thunk info tables
+ -------------------------------------------------------------------------- */
+
+/* When info tables are laid out backwards, we can omit the SRT
+ pointer iff srt_bitmap is zero. */
+
+typedef struct _StgThunkInfoTable {
+#if !defined(TABLES_NEXT_TO_CODE)
+ StgInfoTable i;
+#endif
+ StgSRT *srt; /* pointer to the SRT table */
+#if defined(TABLES_NEXT_TO_CODE)
+ StgInfoTable i;
+#endif
+} StgThunkInfoTable;
#endif /* INFOTABLES_H */
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