X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fincludes%2FInfoTables.h;h=8677e90908dc8fa80a4c91b434e7192da9a2bca4;hb=8504635323bc4c2d7ade98771a4e281c2d56761c;hp=bfaa7d40d090674bafa03d9295525542866392c3;hpb=b4623557bb3c8bec7232e4e68a8be8cf28fbbda6;p=ghc-hetmet.git diff --git a/ghc/includes/InfoTables.h b/ghc/includes/InfoTables.h index bfaa7d4..8677e90 100644 --- a/ghc/includes/InfoTables.h +++ b/ghc/includes/InfoTables.h @@ -1,7 +1,7 @@ /* ---------------------------------------------------------------------------- - * $Id: InfoTables.h,v 1.23 2001/10/03 13:57:42 simonmar Exp $ + * $Id: InfoTables.h,v 1.35 2004/11/08 12:26:55 simonmar Exp $ * - * (c) The GHC Team, 1998-1999 + * (c) The GHC Team, 1998-2002 * * Info Tables * @@ -34,11 +34,6 @@ typedef struct { #endif /* 0 */ -typedef struct { - /* empty */ -} StgParInfo; - - /* Copied from ghc-0.29; ToDo: check this code -- HWL @@ -88,11 +83,9 @@ typedef struct { /* ----------------------------------------------------------------------------- Ticky info - -------------------------------------------------------------------------- */ -typedef struct { - /* empty */ -} StgTickyInfo; + There is no ticky-specific stuff in an info table at this time. + -------------------------------------------------------------------------- */ /* ----------------------------------------------------------------------------- Debugging info @@ -106,12 +99,14 @@ typedef struct { #else /* !DEBUG_CLOSURE */ -typedef struct { - /* empty */ -} StgDebugInfo; +// There is no DEBUG-specific stuff in an info table at this time. #endif /* DEBUG_CLOSURE */ +/* ----------------------------------------------------------------------------- + Closure flags + -------------------------------------------------------------------------- */ + /* The type flags provide quick access to certain properties of a closure. */ #define _HNF (1<<0) /* head normal form? */ @@ -160,54 +155,95 @@ extern StgWord16 closure_flags[]; #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). + + In these bitmaps: 0 == ptr, 1 == non-ptr. -------------------------------------------------------------------------- */ -/* 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) +// +// A large bitmap. +// typedef struct { StgWord size; 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 */ + 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 + +#ifndef TABLES_NEXT_TO_CODE + StgLargeBitmap* large_bitmap; // pointer to large bitmap structure #else - StgWord16 ptrs; /* number of pointers */ - StgWord16 nptrs; /* number of non-pointers */ + StgWord large_bitmap_offset; // offset from info table to large bitmap structure #endif - } payload; + + 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. - */ - -typedef StgClosure* StgSRT[]; +// +// The "standard" part of an info table. Every info table has this bit. +// typedef struct _StgInfoTable { - StgSRT *srt; /* pointer to the SRT table */ + +#ifndef TABLES_NEXT_TO_CODE + StgFunPtr entry; // pointer to the entry code +#endif + #if defined(PAR) || defined(GRAN) struct _StgInfoTable *rbh_infoptr; #endif @@ -215,35 +251,137 @@ typedef struct _StgInfoTable { StgProfInfo prof; #endif #ifdef TICKY - StgTickyInfo ticky; + // Ticky-specific stuff would go here. #endif #ifdef DEBUG_CLOSURE - StgDebugInfo debug; + // Debug-specific stuff would go here. +#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[FLEXIBLE_ARRAY]; +#endif +} StgInfoTable; + + +/* ----------------------------------------------------------------------------- + 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 _StgFunInfoExtraRev { + StgWord slow_apply_offset; // apply to args on the stack + StgWord bitmap; // arg ptr/nonptr bitmap + StgWord srt_offset; // pointer to the SRT table + StgHalfWord fun_type; // function type + StgHalfWord arity; // function arity +} StgFunInfoExtraRev; + +typedef struct _StgFunInfoExtraFwd { + 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 +} StgFunInfoExtraFwd; + +typedef struct { +#if defined(TABLES_NEXT_TO_CODE) + StgFunInfoExtraRev f; + StgInfoTable i; +#else + StgInfoTable i; + StgFunInfoExtraFwd f; +#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 { +#if defined(TABLES_NEXT_TO_CODE) + StgWord srt_offset; // offset to the SRT table + StgInfoTable i; +#else + StgInfoTable i; + StgSRT *srt; // pointer to the SRT table + 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 - StgClosureInfo layout; /* closure layout info (pointer-sized) */ -#if SIZEOF_VOID_P == 8 - StgWord32 type; /* } These 2 elements fit into 64 bits */ - StgWord32 srt_len; /* } */ +#if defined(TABLES_NEXT_TO_CODE) + StgWord srt_offset; // offset to the SRT table #else - StgWord type : 16; /* } These 2 elements fit into 32 bits */ - StgWord srt_len : 16; /* } */ + StgSRT *srt; // pointer to the SRT table #endif +#if defined(TABLES_NEXT_TO_CODE) + StgInfoTable i; +#endif +} StgThunkInfoTable; + + +/* ----------------------------------------------------------------------------- + Accessor macros for fields that might be offsets (C version) + -------------------------------------------------------------------------- */ + +// GET_SRT(info) +// info must be a Stg[Ret|Thunk]InfoTable* (an info table that has a SRT) #ifdef TABLES_NEXT_TO_CODE - StgCode code[FLEXIBLE_ARRAY]; +#define GET_SRT(info) ((StgSRT*) (((StgWord) ((info)+1)) + (info)->srt_offset)) #else - StgFunPtr entry; - StgFunPtr vector[FLEXIBLE_ARRAY]; +#define GET_SRT(info) ((info)->srt) +#endif + +// GET_FUN_SRT(info) +// info must be a StgFunInfoTable* +#ifdef TABLES_NEXT_TO_CODE +#define GET_FUN_SRT(info) ((StgSRT*) (((StgWord) ((info)+1)) + (info)->f.srt_offset)) +#else +#define GET_FUN_SRT(info) ((info)->f.srt) +#endif + +#ifdef TABLES_NEXT_TO_CODE +#define GET_LARGE_BITMAP(info) ((StgLargeBitmap*) (((StgWord) ((info)+1)) \ + + (info)->layout.large_bitmap_offset)) +#else +#define GET_LARGE_BITMAP(info) ((info)->layout.large_bitmap) +#endif + +#ifdef TABLES_NEXT_TO_CODE +#define GET_FUN_LARGE_BITMAP(info) ((StgLargeBitmap*) (((StgWord) ((info)+1)) \ + + (info)->f.bitmap)) +#else +#define GET_FUN_LARGE_BITMAP(info) ((StgLargeBitmap*) ((info)->f.bitmap)) #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 #endif /* INFOTABLES_H */