InfoTables.h 13 KB
Newer Older
1
/* ----------------------------------------------------------------------------
2
 *
3
 * (c) The GHC Team, 1998-2002
4
 *
5 6 7 8
 * Info Tables
 *
 * -------------------------------------------------------------------------- */

Simon Marlow's avatar
Simon Marlow committed
9 10
#ifndef RTS_STORAGE_INFOTABLES_H
#define RTS_STORAGE_INFOTABLES_H
11

Simon Marlow's avatar
Simon Marlow committed
12 13 14 15 16 17
/* ----------------------------------------------------------------------------
   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.
18 19 20 21 22 23 24 25 26 27 28

   Note [x86-64-relative]
   There is a complication on the x86_64 platform, where pointers 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.

   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.
Simon Marlow's avatar
Simon Marlow committed
29 30 31
   ------------------------------------------------------------------------- */

#if x86_64_TARGET_ARCH
32
#define OFFSET_FIELD(n) StgHalfInt n; StgHalfWord __pad_##n
33
#else
34
#define OFFSET_FIELD(n) StgInt n
Simon Marlow's avatar
Simon Marlow committed
35 36
#endif

37 38 39 40 41
/* -----------------------------------------------------------------------------
   Profiling info
   -------------------------------------------------------------------------- */

typedef struct {
Simon Marlow's avatar
Simon Marlow committed
42
#ifndef TABLES_NEXT_TO_CODE
43 44
    char *closure_type;
    char *closure_desc;
Simon Marlow's avatar
Simon Marlow committed
45 46 47 48
#else
    OFFSET_FIELD(closure_type_off);
    OFFSET_FIELD(closure_desc_off);
#endif
49 50
} StgProfInfo;

51 52 53 54
/* -----------------------------------------------------------------------------
   Closure flags
   -------------------------------------------------------------------------- */

55 56
/* The type flags provide quick access to certain properties of a closure. */

57
#define _HNF (1<<0)  /* head normal form?    */
58
#define _BTM (1<<1)  /* uses info->layout.bitmap */
59
#define _NS  (1<<2)  /* non-sparkable        */
Simon Marlow's avatar
Simon Marlow committed
60 61 62 63 64 65
#define _THU (1<<3)  /* thunk?               */
#define _MUT (1<<4)  /* mutable?             */
#define _UPT (1<<5)  /* unpointed?           */
#define _SRT (1<<6)  /* has an SRT?          */
#define _IND (1<<7)  /* is an indirection?   */

66 67 68 69 70
#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)
71

72 73
extern StgWord16 closure_flags[];

74 75
#define closureFlags(c)         (closure_flags[get_itbl \
                                    (UNTAG_CONST_CLOSURE(c))->type])
76

77 78
#define closure_HNF(c)          (  closureFlags(c) & _HNF)
#define closure_BITMAP(c)       (  closureFlags(c) & _BTM)
79
#define closure_NON_SPARK(c)    ( (closureFlags(c) & _NS))
80
#define closure_SHOULD_SPARK(c) (!(closureFlags(c) & _NS))
81
#define closure_THUNK(c)        (  closureFlags(c) & _THU)
82 83
#define closure_MUTABLE(c)      (  closureFlags(c) & _MUT)
#define closure_UNPOINTED(c)    (  closureFlags(c) & _UPT)
84
#define closure_SRT(c)          (  closureFlags(c) & _SRT)
85
#define closure_IND(c)          (  closureFlags(c) & _IND)
86 87 88

/* same as above but for info-ptr rather than closure */
#define ipFlags(ip)             (closure_flags[ip->type])
89

90
#define ip_HNF(ip)               (  ipFlags(ip) & _HNF)
91 92 93 94 95 96 97
#define ip_BITMAP(ip)            (  ipFlags(ip) & _BTM)
#define ip_SHOULD_SPARK(ip)      (!(ipFlags(ip) & _NS))
#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)
98 99

/* -----------------------------------------------------------------------------
100 101 102 103 104 105
   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).
106 107

   In these bitmaps: 0 == ptr, 1 == non-ptr.
108 109
   -------------------------------------------------------------------------- */

110
/*
111
 * Small bitmaps:  for a small bitmap, we store the size and bitmap in
112 113 114
 * 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.
 */
115 116 117 118
#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)
119

120 121 122
/*
 * A large bitmap.
 */
123
typedef struct {
124
  StgWord size;
125
  StgWord bitmap[];
126 127
} StgLargeBitmap;

128 129 130 131 132 133 134 135 136
/* -----------------------------------------------------------------------------
   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.
   -------------------------------------------------------------------------- */

137
/* An SRT is just an array of closure pointers: */
138 139
typedef StgClosure* StgSRT[];

140 141 142 143 144 145 146 147
/*
 * 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:
 */
148 149 150 151 152
typedef struct StgLargeSRT_ {
    StgSRT *srt;
    StgLargeBitmap l;
} StgLargeSRT;

153 154 155
/* ----------------------------------------------------------------------------
   Info Tables
   ------------------------------------------------------------------------- */
156

157 158 159 160 161
/*
 * Stuff describing the closure layout.  Well, actually, it might
 * contain the selector index for a THUNK_SELECTOR.  This union is one
 * word long.
 */
162
typedef union {
163 164 165
    struct {                    /* Heap closure payload layout: */
        StgHalfWord ptrs;       /* number of pointers */
        StgHalfWord nptrs;      /* number of non-pointers */
166
    } payload;
167 168 169

    StgWord bitmap;               /* word-sized bit pattern describing */
                                  /*  a stack frame: see below */
170

171
#ifndef TABLES_NEXT_TO_CODE
172
    StgLargeBitmap* large_bitmap; /* pointer to large bitmap structure */
173
#else
174
    OFFSET_FIELD(large_bitmap_offset);  /* offset from info table to large bitmap structure */
175
#endif
176 177

    StgWord selector_offset;      /* used in THUNK_SELECTORs */
sof's avatar
sof committed
178

179 180 181
} StgClosureInfo;


182 183 184
/*
 * The "standard" part of an info table.  Every info table has this bit.
 */
Simon Marlow's avatar
Simon Marlow committed
185
typedef struct StgInfoTable_ {
186

187
#if !defined(TABLES_NEXT_TO_CODE)
188
    StgFunPtr       entry;      /* pointer to the entry code */
189 190
#endif

sof's avatar
sof committed
191
#ifdef PROFILING
192
    StgProfInfo     prof;
sof's avatar
sof committed
193
#endif
194

195
    StgClosureInfo  layout;     /* closure layout info (one word) */
196

197
    StgHalfWord     type;       /* closure type */
198 199 200 201 202 203
    StgHalfWord     srt_bitmap;
       /* In a CONSTR:
            - the constructor tag
          In a FUN/THUNK
            - a bitmap of SRT entries
       */
204

205
#ifdef TABLES_NEXT_TO_CODE
206
    StgCode         code[];
207
#endif
thomie's avatar
thomie committed
208
} *StgInfoTablePtr; // StgInfoTable defined in rts/Types.h
209

210 211 212 213 214 215 216 217 218 219

/* -----------------------------------------------------------------------------
   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).
220

221
   -  If srt_bitmap (in the std info table part) is zero, then the srt
Ben Gamari's avatar
Ben Gamari committed
222
      field needn't be set.  This only applies if the slow_apply and
223 224 225
      bitmap fields have also been omitted.
   -------------------------------------------------------------------------- */

Ben Gamari's avatar
Ben Gamari committed
226 227 228 229 230 231 232 233 234 235 236
/*
   Note [Encoding static reference tables]
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

   As static reference tables appear frequently in code, we use a special
   compact encoding for the common case of a module defining only a few CAFs: We
   produce one table containing a list of CAFs in the module and then include a
   bitmap in each info table describing which entries of this table the closure
   references.
 */

Simon Marlow's avatar
Simon Marlow committed
237
typedef struct StgFunInfoExtraRev_ {
238
    OFFSET_FIELD(slow_apply_offset); /* apply to args on the stack */
239 240 241
    union {
        StgWord bitmap;
        OFFSET_FIELD(bitmap_offset);    /* arg ptr/nonptr bitmap */
242
    } b;
243
    OFFSET_FIELD(srt_offset);   /* pointer to the SRT table */
244 245
    StgHalfWord    fun_type;    /* function type */
    StgHalfWord    arity;       /* function arity */
246 247
} StgFunInfoExtraRev;

Simon Marlow's avatar
Simon Marlow committed
248
typedef struct StgFunInfoExtraFwd_ {
249 250
    StgHalfWord    fun_type;    /* function type */
    StgHalfWord    arity;       /* function arity */
251
    StgSRT         *srt;        /* pointer to the SRT table */
252
    union { /* union for compat. with TABLES_NEXT_TO_CODE version */
253
        StgWord        bitmap;  /* arg ptr/nonptr bitmap */
254
    } b;
255
    StgFun         *slow_apply; /* apply to args on the stack */
256 257 258 259 260 261 262 263 264
} StgFunInfoExtraFwd;

typedef struct {
#if defined(TABLES_NEXT_TO_CODE)
    StgFunInfoExtraRev f;
    StgInfoTable i;
#else
    StgInfoTable i;
    StgFunInfoExtraFwd f;
265 266 267
#endif
} StgFunInfoTable;

268 269 270
// canned bitmap for each arg type, indexed by constants in FunTypes.h
extern StgWord stg_arg_bitmaps[];

271 272 273 274
/* -----------------------------------------------------------------------------
   Return info tables
   -------------------------------------------------------------------------- */

275 276 277 278
/*
 * When info tables are laid out backwards, we can omit the SRT
 * pointer iff srt_bitmap is zero.
 */
279

280
typedef struct {
281
#if defined(TABLES_NEXT_TO_CODE)
282
    OFFSET_FIELD(srt_offset);   /* offset to the SRT table */
283
    StgInfoTable i;
284 285
#else
    StgInfoTable i;
286
    StgSRT      *srt;   /* pointer to the SRT table */
287 288 289 290 291 292 293
#endif
} StgRetInfoTable;

/* -----------------------------------------------------------------------------
   Thunk info tables
   -------------------------------------------------------------------------- */

294 295 296 297
/*
 * When info tables are laid out backwards, we can omit the SRT
 * pointer iff srt_bitmap is zero.
 */
298

Simon Marlow's avatar
Simon Marlow committed
299
typedef struct StgThunkInfoTable_ {
300 301 302
#if !defined(TABLES_NEXT_TO_CODE)
    StgInfoTable i;
#endif
303
#if defined(TABLES_NEXT_TO_CODE)
304
    OFFSET_FIELD(srt_offset);   /* offset to the SRT table */
305
#else
306
    StgSRT         *srt;        /* pointer to the SRT table */
307
#endif
308 309
#if defined(TABLES_NEXT_TO_CODE)
    StgInfoTable i;
310
#endif
311
} StgThunkInfoTable;
312

313 314 315 316
/* -----------------------------------------------------------------------------
   Constructor info tables
   -------------------------------------------------------------------------- */

Simon Marlow's avatar
Simon Marlow committed
317
typedef struct StgConInfoTable_ {
318 319 320 321
#if !defined(TABLES_NEXT_TO_CODE)
    StgInfoTable i;
#endif

322
#if defined(TABLES_NEXT_TO_CODE)
323
    OFFSET_FIELD(con_desc); // the name of the data constructor
324
                            // as: Package:Module.Name
325 326
#else
    char *con_desc;
Simon Marlow's avatar
Simon Marlow committed
327
#endif
328 329 330 331 332 333

#if defined(TABLES_NEXT_TO_CODE)
    StgInfoTable i;
#endif
} StgConInfoTable;

334 335 336 337 338

/* -----------------------------------------------------------------------------
   Accessor macros for fields that might be offsets (C version)
   -------------------------------------------------------------------------- */

339 340 341 342
/*
 * GET_SRT(info)
 * info must be a Stg[Ret|Thunk]InfoTable* (an info table that has a SRT)
 */
343 344 345 346 347 348
#ifdef TABLES_NEXT_TO_CODE
#define GET_SRT(info) ((StgSRT*) (((StgWord) ((info)+1)) + (info)->srt_offset))
#else
#define GET_SRT(info) ((info)->srt)
#endif

349 350 351 352 353
/*
 * GET_CON_DESC(info)
 * info must be a StgConInfoTable*.
 */
#ifdef TABLES_NEXT_TO_CODE
354 355
#define GET_CON_DESC(info) \
            ((const char *)((StgWord)((info)+1) + (info->con_desc)))
356
#else
357
#define GET_CON_DESC(info) ((const char *)(info)->con_desc)
358 359
#endif

360 361 362 363
/*
 * GET_FUN_SRT(info)
 * info must be a StgFunInfoTable*
 */
364 365 366 367 368 369 370 371 372 373 374 375 376 377 378
#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)) \
379
                                        + (info)->f.b.bitmap_offset))
380
#else
381
#define GET_FUN_LARGE_BITMAP(info) ((StgLargeBitmap*) ((info)->f.b.bitmap))
382 383
#endif

Simon Marlow's avatar
Simon Marlow committed
384 385 386 387 388 389 390 391 392 393 394 395 396
/*
 * 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
Simon Marlow's avatar
Simon Marlow committed
397 398

#endif /* RTS_STORAGE_INFOTABLES_H */