diff options
Diffstat (limited to 'includes/rts/storage/InfoTables.h')
| -rw-r--r-- | includes/rts/storage/InfoTables.h | 96 |
1 files changed, 53 insertions, 43 deletions
diff --git a/includes/rts/storage/InfoTables.h b/includes/rts/storage/InfoTables.h index c621e5e749..db50d1613b 100644 --- a/includes/rts/storage/InfoTables.h +++ b/includes/rts/storage/InfoTables.h @@ -124,31 +124,6 @@ typedef struct { StgWord bitmap[]; } 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 ------------------------------------------------------------------------- */ @@ -178,6 +153,24 @@ typedef union { } StgClosureInfo; +#if defined(x86_64_TARGET_ARCH) && defined(TABLES_NEXT_TO_CODE) +// On x86_64 we can fit a pointer offset in half a word, so put the SRT offset +// in the info->srt field directly. +// +// See the section "Referring to an SRT from the info table" in +// Note [SRTs] in CmmBuildInfoTables.hs +#define USE_INLINE_SRT_FIELD +#endif + +#if defined(USE_INLINE_SRT_FIELD) +// offset to the SRT / closure, or zero if there's no SRT +typedef StgHalfInt StgSRTField; +#else +// non-zero if there is an SRT, the offset is in the optional srt field. +typedef StgHalfWord StgSRTField; +#endif + + /* * The "standard" part of an info table. Every info table has this bit. */ @@ -194,11 +187,14 @@ typedef struct StgInfoTable_ { StgClosureInfo layout; /* closure layout info (one word) */ StgHalfWord type; /* closure type */ - StgHalfWord srt_bitmap; + StgSRTField srt; /* In a CONSTR: - the constructor tag In a FUN/THUNK - - a bitmap of SRT entries + - if USE_INLINE_SRT_FIELD + - offset to the SRT (or zero if no SRT) + - otherwise + - non-zero if there is an SRT, offset is in srt_offset */ #if defined(TABLES_NEXT_TO_CODE) @@ -217,7 +213,7 @@ typedef struct StgInfoTable_ { 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 + - If has_srt (in the std info table part) is zero, then the srt field needn't be set. This only applies if the slow_apply and bitmap fields have also been omitted. -------------------------------------------------------------------------- */ @@ -239,7 +235,9 @@ typedef struct StgFunInfoExtraRev_ { StgWord bitmap; OFFSET_FIELD(bitmap_offset); /* arg ptr/nonptr bitmap */ } b; - OFFSET_FIELD(srt_offset); /* pointer to the SRT table */ +#if !defined(USE_INLINE_SRT_FIELD) + OFFSET_FIELD(srt_offset); /* pointer to the SRT closure */ +#endif StgHalfWord fun_type; /* function type */ StgHalfWord arity; /* function arity */ } StgFunInfoExtraRev; @@ -247,7 +245,7 @@ typedef struct StgFunInfoExtraRev_ { typedef struct StgFunInfoExtraFwd_ { StgHalfWord fun_type; /* function type */ StgHalfWord arity; /* function arity */ - StgSRT *srt; /* pointer to the SRT table */ + StgClosure *srt; /* pointer to the SRT closure */ union { /* union for compat. with TABLES_NEXT_TO_CODE version */ StgWord bitmap; /* arg ptr/nonptr bitmap */ } b; @@ -273,16 +271,18 @@ extern const StgWord stg_arg_bitmaps[]; /* * When info tables are laid out backwards, we can omit the SRT - * pointer iff srt_bitmap is zero. + * pointer iff has_srt is zero. */ typedef struct { #if defined(TABLES_NEXT_TO_CODE) - OFFSET_FIELD(srt_offset); /* offset to the SRT table */ +#if !defined(USE_INLINE_SRT_FIELD) + OFFSET_FIELD(srt_offset); /* offset to the SRT closure */ +#endif StgInfoTable i; #else StgInfoTable i; - StgSRT *srt; /* pointer to the SRT table */ + StgClosure *srt; /* pointer to the SRT closure */ #endif } StgRetInfoTable; @@ -292,20 +292,18 @@ typedef struct { /* * When info tables are laid out backwards, we can omit the SRT - * pointer iff srt_bitmap is zero. + * pointer iff has_srt 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 */ +#if !defined(USE_INLINE_SRT_FIELD) + OFFSET_FIELD(srt_offset); /* offset to the SRT closure */ #endif -#if defined(TABLES_NEXT_TO_CODE) StgInfoTable i; +#else + StgInfoTable i; + StgClosure *srt; /* pointer to the SRT closure */ #endif } StgThunkInfoTable; @@ -340,8 +338,14 @@ typedef struct StgConInfoTable_ { * info must be a Stg[Ret|Thunk]InfoTable* (an info table that has a SRT) */ #if defined(TABLES_NEXT_TO_CODE) -#define GET_SRT(info) ((StgSRT*) (((StgWord) ((info)+1)) + (info)->srt_offset)) +#if defined(x86_64_TARGET_ARCH) +#define GET_SRT(info) \ + ((StgClosure*) (((StgWord) ((info)+1)) + (info)->i.srt)) #else +#define GET_SRT(info) \ + ((StgClosure*) (((StgWord) ((info)+1)) + (info)->srt_offset)) +#endif +#else // !TABLES_NEXT_TO_CODE #define GET_SRT(info) ((info)->srt) #endif @@ -361,7 +365,13 @@ typedef struct StgConInfoTable_ { * info must be a StgFunInfoTable* */ #if defined(TABLES_NEXT_TO_CODE) -#define GET_FUN_SRT(info) ((StgSRT*) (((StgWord) ((info)+1)) + (info)->f.srt_offset)) +#if defined(x86_64_TARGET_ARCH) +#define GET_FUN_SRT(info) \ + ((StgClosure*) (((StgWord) ((info)+1)) + (info)->i.srt)) +#else +#define GET_FUN_SRT(info) \ + ((StgClosure*) (((StgWord) ((info)+1)) + (info)->f.srt_offset)) +#endif #else #define GET_FUN_SRT(info) ((info)->f.srt) #endif |