/* ---------------------------------------------------------------------------- * * (c) The GHC Team, 1998-2002 * * Info Tables * * -------------------------------------------------------------------------- */ #ifndef RTS_STORAGE_INFOTABLES_H #define RTS_STORAGE_INFOTABLES_H /* ---------------------------------------------------------------------------- Relative pointers Several pointer fields in info tables are expressed as offsets relative to the info pointer, so that we can generate position-independent code. Note [x86-64-relative] There is a complication on the x86_64 platform, where pointeres are 64 bits, but the tools don't support 64-bit relative relocations. However, the default memory model (small) ensures that all symbols have values in the lower 2Gb of the address space, so offsets all fit in 32 bits. Hence we can use 32-bit offset fields. When going via-C, the mangler arranges that we only generate relative relocations between symbols in the same segment (the text segment). The NCG, however, puts things in the right sections and uses 32-bit relative offsets instead. Somewhere between binutils-2.16.1 and binutils-2.16.91.0.6, support for 64-bit PC-relative relocations was added, so maybe this hackery can go away sometime. ------------------------------------------------------------------------- */ #if x86_64_TARGET_ARCH #define OFFSET_FIELD(n) StgHalfInt n; StgHalfWord __pad_##n; #else #define OFFSET_FIELD(n) StgInt n; #endif /* ----------------------------------------------------------------------------- Profiling info -------------------------------------------------------------------------- */ typedef struct { #ifndef TABLES_NEXT_TO_CODE char *closure_type; char *closure_desc; #else OFFSET_FIELD(closure_type_off); OFFSET_FIELD(closure_desc_off); #endif } StgProfInfo; /* ----------------------------------------------------------------------------- Ticky info There is no ticky-specific stuff in an info table at this time. -------------------------------------------------------------------------- */ /* ----------------------------------------------------------------------------- Debugging info -------------------------------------------------------------------------- */ #ifdef DEBUG_CLOSURE typedef struct { ... whatever ... } StgDebugInfo; #else /* !DEBUG_CLOSURE */ /* 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? */ #define _BTM (1<<1) /* bitmap-style layout? */ #define _NS (1<<2) /* non-sparkable */ #define _STA (1<<3) /* static? */ #define _THU (1<<4) /* thunk? */ #define _MUT (1<<5) /* mutable? */ #define _UPT (1<<6) /* unpointed? */ #define _SRT (1<<7) /* has an SRT? */ #define _IND (1<<8) /* is an indirection? */ #define isSTATIC(flags) ((flags) &_STA) #define isMUTABLE(flags) ((flags) &_MUT) #define isBITMAP(flags) ((flags) &_BTM) #define isTHUNK(flags) ((flags) &_THU) #define isUNPOINTED(flags) ((flags) &_UPT) #define hasSRT(flags) ((flags) &_SRT) extern StgWord16 closure_flags[]; #define closureFlags(c) (closure_flags[get_itbl(UNTAG_CLOSURE(c))->type]) #define closure_HNF(c) ( closureFlags(c) & _HNF) #define closure_BITMAP(c) ( closureFlags(c) & _BTM) #define closure_NON_SPARK(c) ( (closureFlags(c) & _NS)) #define closure_SHOULD_SPARK(c) (!(closureFlags(c) & _NS)) #define closure_STATIC(c) ( closureFlags(c) & _STA) #define closure_THUNK(c) ( closureFlags(c) & _THU) #define closure_MUTABLE(c) ( closureFlags(c) & _MUT) #define closure_UNPOINTED(c) ( closureFlags(c) & _UPT) #define closure_SRT(c) ( closureFlags(c) & _SRT) #define closure_IND(c) ( closureFlags(c) & _IND) /* same as above but for info-ptr rather than closure */ #define ipFlags(ip) (closure_flags[ip->type]) #define ip_HNF(ip) ( ipFlags(ip) & _HNF) #define ip_BITMAP(ip) ( ipFlags(ip) & _BTM) #define ip_SHOULD_SPARK(ip) (!(ipFlags(ip) & _NS)) #define ip_STATIC(ip) ( ipFlags(ip) & _STA) #define ip_THUNK(ip) ( ipFlags(ip) & _THU) #define ip_MUTABLE(ip) ( ipFlags(ip) & _MUT) #define ip_UNPOINTED(ip) ( ipFlags(ip) & _UPT) #define ip_SRT(ip) ( ipFlags(ip) & _SRT) #define ip_IND(ip) ( ipFlags(ip) & _IND) /* ----------------------------------------------------------------------------- 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. -------------------------------------------------------------------------- */ /* * 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; /* ----------------------------------------------------------------------------- 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 { /* 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 OFFSET_FIELD( large_bitmap_offset ); /* offset from info table to large bitmap structure */ #endif StgWord selector_offset; /* used in THUNK_SELECTORs */ } StgClosureInfo; /* * The "standard" part of an info table. Every info table has this bit. */ typedef struct StgInfoTable_ { #ifndef TABLES_NEXT_TO_CODE StgFunPtr entry; /* pointer to the entry code */ #endif #ifdef PROFILING StgProfInfo prof; #endif #ifdef TICKY /* Ticky-specific stuff would go here. */ #endif #ifdef DEBUG_CLOSURE /* Debug-specific stuff would go here. */ #endif StgClosureInfo layout; /* closure layout info (one word) */ StgHalfWord type; /* closure type */ StgHalfWord srt_bitmap; /* In a CONSTR: - the constructor tag In a FUN/THUNK - a bitmap of SRT entries */ #ifdef TABLES_NEXT_TO_CODE StgCode code[FLEXIBLE_ARRAY]; #endif } *StgInfoTablePtr; /* ----------------------------------------------------------------------------- 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_ { OFFSET_FIELD ( slow_apply_offset ); /* apply to args on the stack */ union { StgWord bitmap; OFFSET_FIELD ( bitmap_offset ); /* arg ptr/nonptr bitmap */ } b; OFFSET_FIELD ( 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 */ union { /* union for compat. with TABLES_NEXT_TO_CODE version */ StgWord bitmap; /* arg ptr/nonptr bitmap */ } b; 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) OFFSET_FIELD( srt_offset ); /* offset to the SRT table */ StgInfoTable i; #else StgInfoTable i; StgSRT *srt; /* pointer to the SRT table */ #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 #if defined(TABLES_NEXT_TO_CODE) OFFSET_FIELD( srt_offset ); /* offset to the SRT table */ #else StgSRT *srt; /* pointer to the SRT table */ #endif #if defined(TABLES_NEXT_TO_CODE) StgInfoTable i; #endif } StgThunkInfoTable; /* ----------------------------------------------------------------------------- Constructor info tables -------------------------------------------------------------------------- */ typedef struct StgConInfoTable_ { #if !defined(TABLES_NEXT_TO_CODE) StgInfoTable i; #endif #ifndef TABLES_NEXT_TO_CODE char *con_desc; #else OFFSET_FIELD(con_desc) // the name of the data constructor // as: Package:Module.Name #endif #if defined(TABLES_NEXT_TO_CODE) StgInfoTable i; #endif } StgConInfoTable; /* ----------------------------------------------------------------------------- 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 #define GET_SRT(info) ((StgSRT*) (((StgWord) ((info)+1)) + (info)->srt_offset)) #else #define GET_SRT(info) ((info)->srt) #endif /* * GET_CON_DESC(info) * info must be a StgConInfoTable*. */ #ifdef TABLES_NEXT_TO_CODE #define GET_CON_DESC(info) ((char *)((StgWord)((info)+1) + (info->con_desc))) #else #define GET_CON_DESC(info) ((info)->con_desc) #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.b.bitmap_offset)) #else #define GET_FUN_LARGE_BITMAP(info) ((StgLargeBitmap*) ((info)->f.b.bitmap)) #endif /* * GET_PROF_TYPE, GET_PROF_DESC */ #ifdef TABLES_NEXT_TO_CODE #define GET_PROF_TYPE(info) ((char *)((StgWord)((info)+1) + (info->prof.closure_type_off))) #else #define GET_PROF_TYPE(info) ((info)->prof.closure_type) #endif #ifdef TABLES_NEXT_TO_CODE #define GET_PROF_DESC(info) ((char *)((StgWord)((info)+1) + (info->prof.closure_desc_off))) #else #define GET_PROF_DESC(info) ((info)->prof.closure_desc) #endif #endif /* RTS_STORAGE_INFOTABLES_H */