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

9
#pragma once
10

Simon Marlow's avatar
Simon Marlow committed
11 12 13 14 15 16
/* ----------------------------------------------------------------------------
   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.
17 18 19 20 21 22 23 24 25 26 27

   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
28 29
   ------------------------------------------------------------------------- */

Ben Gamari's avatar
Ben Gamari committed
30
#if defined(x86_64_TARGET_ARCH)
31
#define OFFSET_FIELD(n) StgHalfInt n; StgHalfWord __pad_##n
32
#else
33
#define OFFSET_FIELD(n) StgInt n
Simon Marlow's avatar
Simon Marlow committed
34 35
#endif

36 37 38 39 40
/* -----------------------------------------------------------------------------
   Profiling info
   -------------------------------------------------------------------------- */

typedef struct {
Ben Gamari's avatar
Ben Gamari committed
41
#if !defined(TABLES_NEXT_TO_CODE)
42 43
    char *closure_type;
    char *closure_desc;
Simon Marlow's avatar
Simon Marlow committed
44 45 46 47
#else
    OFFSET_FIELD(closure_type_off);
    OFFSET_FIELD(closure_desc_off);
#endif
48 49
} StgProfInfo;

50 51 52 53
/* -----------------------------------------------------------------------------
   Closure flags
   -------------------------------------------------------------------------- */

54 55
/* The type flags provide quick access to certain properties of a closure. */

56
#define _HNF (1<<0)  /* head normal form?    */
57
#define _BTM (1<<1)  /* uses info->layout.bitmap */
58
#define _NS  (1<<2)  /* non-sparkable        */
Simon Marlow's avatar
Simon Marlow committed
59 60 61 62 63 64
#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?   */

65 66 67 68 69
#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)
70

71 72
extern StgWord16 closure_flags[];

73 74
#define closureFlags(c)         (closure_flags[get_itbl \
                                    (UNTAG_CONST_CLOSURE(c))->type])
75

76 77
#define closure_HNF(c)          (  closureFlags(c) & _HNF)
#define closure_BITMAP(c)       (  closureFlags(c) & _BTM)
78
#define closure_NON_SPARK(c)    ( (closureFlags(c) & _NS))
79
#define closure_SHOULD_SPARK(c) (!(closureFlags(c) & _NS))
80
#define closure_THUNK(c)        (  closureFlags(c) & _THU)
81 82
#define closure_MUTABLE(c)      (  closureFlags(c) & _MUT)
#define closure_UNPOINTED(c)    (  closureFlags(c) & _UPT)
83
#define closure_SRT(c)          (  closureFlags(c) & _SRT)
84
#define closure_IND(c)          (  closureFlags(c) & _IND)
85 86 87

/* same as above but for info-ptr rather than closure */
#define ipFlags(ip)             (closure_flags[ip->type])
88

89
#define ip_HNF(ip)               (  ipFlags(ip) & _HNF)
90 91 92 93 94 95 96
#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)
97 98

/* -----------------------------------------------------------------------------
99 100 101 102 103 104
   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).
105 106

   In these bitmaps: 0 == ptr, 1 == non-ptr.
107 108
   -------------------------------------------------------------------------- */

109
/*
110
 * Small bitmaps:  for a small bitmap, we store the size and bitmap in
111 112 113
 * 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.
 */
114 115 116 117
#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)
118

119 120 121
/*
 * A large bitmap.
 */
122
typedef struct {
123
  StgWord size;
124
  StgWord bitmap[];
125 126
} StgLargeBitmap;

127 128 129 130 131 132 133 134 135
/* -----------------------------------------------------------------------------
   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.
   -------------------------------------------------------------------------- */

136
/* An SRT is just an array of closure pointers: */
137 138
typedef StgClosure* StgSRT[];

139 140 141 142 143 144 145 146
/*
 * 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:
 */
147 148 149 150 151
typedef struct StgLargeSRT_ {
    StgSRT *srt;
    StgLargeBitmap l;
} StgLargeSRT;

152 153 154
/* ----------------------------------------------------------------------------
   Info Tables
   ------------------------------------------------------------------------- */
155

156 157 158 159 160
/*
 * Stuff describing the closure layout.  Well, actually, it might
 * contain the selector index for a THUNK_SELECTOR.  This union is one
 * word long.
 */
161
typedef union {
162 163 164
    struct {                    /* Heap closure payload layout: */
        StgHalfWord ptrs;       /* number of pointers */
        StgHalfWord nptrs;      /* number of non-pointers */
165
    } payload;
166 167 168

    StgWord bitmap;               /* word-sized bit pattern describing */
                                  /*  a stack frame: see below */
169

Ben Gamari's avatar
Ben Gamari committed
170
#if !defined(TABLES_NEXT_TO_CODE)
171
    StgLargeBitmap* large_bitmap; /* pointer to large bitmap structure */
172
#else
173
    OFFSET_FIELD(large_bitmap_offset);  /* offset from info table to large bitmap structure */
174
#endif
175 176

    StgWord selector_offset;      /* used in THUNK_SELECTORs */
sof's avatar
sof committed
177

178 179 180
} StgClosureInfo;


181 182 183
/*
 * The "standard" part of an info table.  Every info table has this bit.
 */
Simon Marlow's avatar
Simon Marlow committed
184
typedef struct StgInfoTable_ {
185

186
#if !defined(TABLES_NEXT_TO_CODE)
187
    StgFunPtr       entry;      /* pointer to the entry code */
188 189
#endif

Ben Gamari's avatar
Ben Gamari committed
190
#if defined(PROFILING)
191
    StgProfInfo     prof;
sof's avatar
sof committed
192
#endif
193

194
    StgClosureInfo  layout;     /* closure layout info (one word) */
195

196
    StgHalfWord     type;       /* closure type */
197 198 199 200 201 202
    StgHalfWord     srt_bitmap;
       /* In a CONSTR:
            - the constructor tag
          In a FUN/THUNK
            - a bitmap of SRT entries
       */
203

Ben Gamari's avatar
Ben Gamari committed
204
#if defined(TABLES_NEXT_TO_CODE)
205
    StgCode         code[];
206
#endif
thomie's avatar
thomie committed
207
} *StgInfoTablePtr; // StgInfoTable defined in rts/Types.h
208

209 210 211 212 213 214 215 216 217 218

/* -----------------------------------------------------------------------------
   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).
219

220
   -  If srt_bitmap (in the std info table part) is zero, then the srt
Ben Gamari's avatar
Ben Gamari committed
221
      field needn't be set.  This only applies if the slow_apply and
222 223 224
      bitmap fields have also been omitted.
   -------------------------------------------------------------------------- */

Ben Gamari's avatar
Ben Gamari committed
225 226 227 228 229 230 231 232 233 234 235
/*
   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
236
typedef struct StgFunInfoExtraRev_ {
237
    OFFSET_FIELD(slow_apply_offset); /* apply to args on the stack */
238 239 240
    union {
        StgWord bitmap;
        OFFSET_FIELD(bitmap_offset);    /* arg ptr/nonptr bitmap */
241
    } b;
242
    OFFSET_FIELD(srt_offset);   /* pointer to the SRT table */
243 244
    StgHalfWord    fun_type;    /* function type */
    StgHalfWord    arity;       /* function arity */
245 246
} StgFunInfoExtraRev;

Simon Marlow's avatar
Simon Marlow committed
247
typedef struct StgFunInfoExtraFwd_ {
248 249
    StgHalfWord    fun_type;    /* function type */
    StgHalfWord    arity;       /* function arity */
250
    StgSRT         *srt;        /* pointer to the SRT table */
251
    union { /* union for compat. with TABLES_NEXT_TO_CODE version */
252
        StgWord        bitmap;  /* arg ptr/nonptr bitmap */
253
    } b;
254
    StgFun         *slow_apply; /* apply to args on the stack */
255 256 257 258 259 260 261 262 263
} StgFunInfoExtraFwd;

typedef struct {
#if defined(TABLES_NEXT_TO_CODE)
    StgFunInfoExtraRev f;
    StgInfoTable i;
#else
    StgInfoTable i;
    StgFunInfoExtraFwd f;
264 265 266
#endif
} StgFunInfoTable;

267
// canned bitmap for each arg type, indexed by constants in FunTypes.h
268
extern const StgWord stg_arg_bitmaps[];
269

270 271 272 273
/* -----------------------------------------------------------------------------
   Return info tables
   -------------------------------------------------------------------------- */

274 275 276 277
/*
 * When info tables are laid out backwards, we can omit the SRT
 * pointer iff srt_bitmap is zero.
 */
278

279
typedef struct {
280
#if defined(TABLES_NEXT_TO_CODE)
281
    OFFSET_FIELD(srt_offset);   /* offset to the SRT table */
282
    StgInfoTable i;
283 284
#else
    StgInfoTable i;
285
    StgSRT      *srt;   /* pointer to the SRT table */
286 287 288 289 290 291 292
#endif
} StgRetInfoTable;

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

293 294 295 296
/*
 * When info tables are laid out backwards, we can omit the SRT
 * pointer iff srt_bitmap is zero.
 */
297

Simon Marlow's avatar
Simon Marlow committed
298
typedef struct StgThunkInfoTable_ {
299 300 301
#if !defined(TABLES_NEXT_TO_CODE)
    StgInfoTable i;
#endif
302
#if defined(TABLES_NEXT_TO_CODE)
303
    OFFSET_FIELD(srt_offset);   /* offset to the SRT table */
304
#else
305
    StgSRT         *srt;        /* pointer to the SRT table */
306
#endif
307 308
#if defined(TABLES_NEXT_TO_CODE)
    StgInfoTable i;
309
#endif
310
} StgThunkInfoTable;
311

312 313 314 315
/* -----------------------------------------------------------------------------
   Constructor info tables
   -------------------------------------------------------------------------- */

Simon Marlow's avatar
Simon Marlow committed
316
typedef struct StgConInfoTable_ {
317 318 319 320
#if !defined(TABLES_NEXT_TO_CODE)
    StgInfoTable i;
#endif

321
#if defined(TABLES_NEXT_TO_CODE)
322
    OFFSET_FIELD(con_desc); // the name of the data constructor
323
                            // as: Package:Module.Name
324 325
#else
    char *con_desc;
Simon Marlow's avatar
Simon Marlow committed
326
#endif
327 328 329 330 331 332

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

333 334 335 336 337

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

338 339 340 341
/*
 * GET_SRT(info)
 * info must be a Stg[Ret|Thunk]InfoTable* (an info table that has a SRT)
 */
Ben Gamari's avatar
Ben Gamari committed
342
#if defined(TABLES_NEXT_TO_CODE)
343 344 345 346 347
#define GET_SRT(info) ((StgSRT*) (((StgWord) ((info)+1)) + (info)->srt_offset))
#else
#define GET_SRT(info) ((info)->srt)
#endif

348 349 350 351
/*
 * GET_CON_DESC(info)
 * info must be a StgConInfoTable*.
 */
Ben Gamari's avatar
Ben Gamari committed
352
#if defined(TABLES_NEXT_TO_CODE)
353 354
#define GET_CON_DESC(info) \
            ((const char *)((StgWord)((info)+1) + (info->con_desc)))
355
#else
356
#define GET_CON_DESC(info) ((const char *)(info)->con_desc)
357 358
#endif

359 360 361 362
/*
 * GET_FUN_SRT(info)
 * info must be a StgFunInfoTable*
 */
Ben Gamari's avatar
Ben Gamari committed
363
#if defined(TABLES_NEXT_TO_CODE)
364 365 366 367 368
#define GET_FUN_SRT(info) ((StgSRT*) (((StgWord) ((info)+1)) + (info)->f.srt_offset))
#else
#define GET_FUN_SRT(info) ((info)->f.srt)
#endif

Ben Gamari's avatar
Ben Gamari committed
369
#if defined(TABLES_NEXT_TO_CODE)
370 371 372 373 374 375
#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

Ben Gamari's avatar
Ben Gamari committed
376
#if defined(TABLES_NEXT_TO_CODE)
377
#define GET_FUN_LARGE_BITMAP(info) ((StgLargeBitmap*) (((StgWord) ((info)+1)) \
378
                                        + (info)->f.b.bitmap_offset))
379
#else
380
#define GET_FUN_LARGE_BITMAP(info) ((StgLargeBitmap*) ((info)->f.b.bitmap))
381 382
#endif

Simon Marlow's avatar
Simon Marlow committed
383 384 385
/*
 * GET_PROF_TYPE, GET_PROF_DESC
 */
Ben Gamari's avatar
Ben Gamari committed
386
#if defined(TABLES_NEXT_TO_CODE)
Simon Marlow's avatar
Simon Marlow committed
387 388 389 390
#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
Ben Gamari's avatar
Ben Gamari committed
391
#if defined(TABLES_NEXT_TO_CODE)
Simon Marlow's avatar
Simon Marlow committed
392 393 394 395
#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