Snapshot of codegen refactoring to share with simonpj
[ghc.git] / includes / rts / storage / InfoTables.h
1 /* ----------------------------------------------------------------------------
2 *
3 * (c) The GHC Team, 1998-2002
4 *
5 * Info Tables
6 *
7 * -------------------------------------------------------------------------- */
8
9 #ifndef RTS_STORAGE_INFOTABLES_H
10 #define RTS_STORAGE_INFOTABLES_H
11
12 /* ----------------------------------------------------------------------------
13 Relative pointers
14
15 Several pointer fields in info tables are expressed as offsets
16 relative to the info pointer, so that we can generate
17 position-independent code.
18
19 Note [x86-64-relative]
20 There is a complication on the x86_64 platform, where pointeres are
21 64 bits, but the tools don't support 64-bit relative relocations.
22 However, the default memory model (small) ensures that all symbols
23 have values in the lower 2Gb of the address space, so offsets all
24 fit in 32 bits. Hence we can use 32-bit offset fields.
25
26 When going via-C, the mangler arranges that we only generate
27 relative relocations between symbols in the same segment (the text
28 segment). The NCG, however, puts things in the right sections and
29 uses 32-bit relative offsets instead.
30
31 Somewhere between binutils-2.16.1 and binutils-2.16.91.0.6,
32 support for 64-bit PC-relative relocations was added, so maybe this
33 hackery can go away sometime.
34 ------------------------------------------------------------------------- */
35
36 #if x86_64_TARGET_ARCH
37 #define OFFSET_FIELD(n) StgHalfInt n; StgHalfWord __pad_##n;
38 #else
39 #define OFFSET_FIELD(n) StgInt n;
40 #endif
41
42 /* -----------------------------------------------------------------------------
43 Profiling info
44 -------------------------------------------------------------------------- */
45
46 typedef struct {
47 #ifndef TABLES_NEXT_TO_CODE
48 char *closure_type;
49 char *closure_desc;
50 #else
51 OFFSET_FIELD(closure_type_off);
52 OFFSET_FIELD(closure_desc_off);
53 #endif
54 } StgProfInfo;
55
56 /* -----------------------------------------------------------------------------
57 Ticky info
58
59 There is no ticky-specific stuff in an info table at this time.
60 -------------------------------------------------------------------------- */
61
62 /* -----------------------------------------------------------------------------
63 Debugging info
64 -------------------------------------------------------------------------- */
65
66 #ifdef DEBUG_CLOSURE
67
68 typedef struct {
69 ... whatever ...
70 } StgDebugInfo;
71
72 #else /* !DEBUG_CLOSURE */
73
74 /* There is no DEBUG-specific stuff in an info table at this time. */
75
76 #endif /* DEBUG_CLOSURE */
77
78 /* -----------------------------------------------------------------------------
79 Closure flags
80 -------------------------------------------------------------------------- */
81
82 /* The type flags provide quick access to certain properties of a closure. */
83
84 #define _HNF (1<<0) /* head normal form? */
85 #define _BTM (1<<1) /* bitmap-style layout? */
86 #define _NS (1<<2) /* non-sparkable */
87 #define _STA (1<<3) /* static? */
88 #define _THU (1<<4) /* thunk? */
89 #define _MUT (1<<5) /* mutable? */
90 #define _UPT (1<<6) /* unpointed? */
91 #define _SRT (1<<7) /* has an SRT? */
92 #define _IND (1<<8) /* is an indirection? */
93
94 #define isSTATIC(flags) ((flags) &_STA)
95 #define isMUTABLE(flags) ((flags) &_MUT)
96 #define isBITMAP(flags) ((flags) &_BTM)
97 #define isTHUNK(flags) ((flags) &_THU)
98 #define isUNPOINTED(flags) ((flags) &_UPT)
99 #define hasSRT(flags) ((flags) &_SRT)
100
101 extern StgWord16 closure_flags[];
102
103 #define closureFlags(c) (closure_flags[get_itbl(UNTAG_CLOSURE(c))->type])
104
105 #define closure_HNF(c) ( closureFlags(c) & _HNF)
106 #define closure_BITMAP(c) ( closureFlags(c) & _BTM)
107 #define closure_NON_SPARK(c) ( (closureFlags(c) & _NS))
108 #define closure_SHOULD_SPARK(c) (!(closureFlags(c) & _NS))
109 #define closure_STATIC(c) ( closureFlags(c) & _STA)
110 #define closure_THUNK(c) ( closureFlags(c) & _THU)
111 #define closure_MUTABLE(c) ( closureFlags(c) & _MUT)
112 #define closure_UNPOINTED(c) ( closureFlags(c) & _UPT)
113 #define closure_SRT(c) ( closureFlags(c) & _SRT)
114 #define closure_IND(c) ( closureFlags(c) & _IND)
115
116 /* same as above but for info-ptr rather than closure */
117 #define ipFlags(ip) (closure_flags[ip->type])
118
119 #define ip_HNF(ip) ( ipFlags(ip) & _HNF)
120 #define ip_BITMAP(ip) ( ipFlags(ip) & _BTM)
121 #define ip_SHOULD_SPARK(ip) (!(ipFlags(ip) & _NS))
122 #define ip_STATIC(ip) ( ipFlags(ip) & _STA)
123 #define ip_THUNK(ip) ( ipFlags(ip) & _THU)
124 #define ip_MUTABLE(ip) ( ipFlags(ip) & _MUT)
125 #define ip_UNPOINTED(ip) ( ipFlags(ip) & _UPT)
126 #define ip_SRT(ip) ( ipFlags(ip) & _SRT)
127 #define ip_IND(ip) ( ipFlags(ip) & _IND)
128
129 /* -----------------------------------------------------------------------------
130 Bitmaps
131
132 These are used to describe the pointerhood of a sequence of words
133 (usually on the stack) to the garbage collector. The two primary
134 uses are for stack frames, and functions (where we need to describe
135 the layout of a PAP to the GC).
136
137 In these bitmaps: 0 == ptr, 1 == non-ptr.
138 -------------------------------------------------------------------------- */
139
140 /*
141 * Small bitmaps: for a small bitmap, we store the size and bitmap in
142 * the same word, using the following macros. If the bitmap doesn't
143 * fit in a single word, we use a pointer to an StgLargeBitmap below.
144 */
145 #define MK_SMALL_BITMAP(size,bits) (((bits)<<BITMAP_BITS_SHIFT) | (size))
146
147 #define BITMAP_SIZE(bitmap) ((bitmap) & BITMAP_SIZE_MASK)
148 #define BITMAP_BITS(bitmap) ((bitmap) >> BITMAP_BITS_SHIFT)
149
150 /*
151 * A large bitmap.
152 */
153 typedef struct {
154 StgWord size;
155 StgWord bitmap[FLEXIBLE_ARRAY];
156 } StgLargeBitmap;
157
158 /* -----------------------------------------------------------------------------
159 SRTs (Static Reference Tables)
160
161 These tables are used to keep track of the static objects referred
162 to by the code for a closure or stack frame, so that we can follow
163 static data references from code and thus accurately
164 garbage-collect CAFs.
165 -------------------------------------------------------------------------- */
166
167 /* An SRT is just an array of closure pointers: */
168 typedef StgClosure* StgSRT[];
169
170 /*
171 * Each info table refers to some subset of the closure pointers in an
172 * SRT. It does this using a pair of an StgSRT pointer and a
173 * half-word bitmap. If the half-word bitmap isn't large enough, then
174 * we fall back to a large SRT, including an unbounded bitmap. If the
175 * half-word bitmap is set to all ones (0xffff), then the StgSRT
176 * pointer instead points to an StgLargeSRT:
177 */
178 typedef struct StgLargeSRT_ {
179 StgSRT *srt;
180 StgLargeBitmap l;
181 } StgLargeSRT;
182
183 /* ----------------------------------------------------------------------------
184 Info Tables
185 ------------------------------------------------------------------------- */
186
187 /*
188 * Stuff describing the closure layout. Well, actually, it might
189 * contain the selector index for a THUNK_SELECTOR. This union is one
190 * word long.
191 */
192 typedef union {
193 struct { /* Heap closure payload layout: */
194 StgHalfWord ptrs; /* number of pointers */
195 StgHalfWord nptrs; /* number of non-pointers */
196 } payload;
197
198 StgWord bitmap; /* word-sized bit pattern describing */
199 /* a stack frame: see below */
200
201 #ifndef TABLES_NEXT_TO_CODE
202 StgLargeBitmap* large_bitmap; /* pointer to large bitmap structure */
203 #else
204 OFFSET_FIELD( large_bitmap_offset ); /* offset from info table to large bitmap structure */
205 #endif
206
207 StgWord selector_offset; /* used in THUNK_SELECTORs */
208
209 } StgClosureInfo;
210
211
212 /*
213 * The "standard" part of an info table. Every info table has this bit.
214 */
215 typedef struct StgInfoTable_ {
216
217 #if !defined(TABLES_NEXT_TO_CODE)
218 StgFunPtr entry; /* pointer to the entry code */
219 #endif
220
221 #ifdef PROFILING
222 StgProfInfo prof;
223 #endif
224 #ifdef TICKY
225 /* Ticky-specific stuff would go here. */
226 #endif
227 #ifdef DEBUG_CLOSURE
228 /* Debug-specific stuff would go here. */
229 #endif
230
231 StgClosureInfo layout; /* closure layout info (one word) */
232
233 StgHalfWord type; /* closure type */
234 StgHalfWord srt_bitmap;
235 /* In a CONSTR:
236 - the constructor tag
237 In a FUN/THUNK
238 - a bitmap of SRT entries
239 */
240
241 #ifdef TABLES_NEXT_TO_CODE
242 StgCode code[FLEXIBLE_ARRAY];
243 #endif
244 } *StgInfoTablePtr;
245
246
247 /* -----------------------------------------------------------------------------
248 Function info tables
249
250 This is the general form of function info tables. The compiler
251 will omit some of the fields in common cases:
252
253 - If fun_type is not ARG_GEN or ARG_GEN_BIG, then the slow_apply
254 and bitmap fields may be left out (they are at the end, so omitting
255 them doesn't affect the layout).
256
257 - If srt_bitmap (in the std info table part) is zero, then the srt
258 field may be omitted. This only applies if the slow_apply and
259 bitmap fields have also been omitted.
260 -------------------------------------------------------------------------- */
261
262 typedef struct StgFunInfoExtraRev_ {
263 OFFSET_FIELD ( slow_apply_offset ); /* apply to args on the stack */
264 union {
265 StgWord bitmap;
266 OFFSET_FIELD ( bitmap_offset ); /* arg ptr/nonptr bitmap */
267 } b;
268 OFFSET_FIELD ( srt_offset ); /* pointer to the SRT table */
269 StgHalfWord fun_type; /* function type */
270 StgHalfWord arity; /* function arity */
271 } StgFunInfoExtraRev;
272
273 typedef struct StgFunInfoExtraFwd_ {
274 StgHalfWord fun_type; /* function type */
275 StgHalfWord arity; /* function arity */
276 StgSRT *srt; /* pointer to the SRT table */
277 union { /* union for compat. with TABLES_NEXT_TO_CODE version */
278 StgWord bitmap; /* arg ptr/nonptr bitmap */
279 } b;
280 StgFun *slow_apply; /* apply to args on the stack */
281 } StgFunInfoExtraFwd;
282
283 typedef struct {
284 #if defined(TABLES_NEXT_TO_CODE)
285 StgFunInfoExtraRev f;
286 StgInfoTable i;
287 #else
288 StgInfoTable i;
289 StgFunInfoExtraFwd f;
290 #endif
291 } StgFunInfoTable;
292
293 // canned bitmap for each arg type, indexed by constants in FunTypes.h
294 extern StgWord stg_arg_bitmaps[];
295
296 /* -----------------------------------------------------------------------------
297 Return info tables
298 -------------------------------------------------------------------------- */
299
300 /*
301 * When info tables are laid out backwards, we can omit the SRT
302 * pointer iff srt_bitmap is zero.
303 */
304
305 typedef struct {
306 #if defined(TABLES_NEXT_TO_CODE)
307 OFFSET_FIELD( srt_offset ); /* offset to the SRT table */
308 StgInfoTable i;
309 #else
310 StgInfoTable i;
311 StgSRT *srt; /* pointer to the SRT table */
312 #endif
313 } StgRetInfoTable;
314
315 /* -----------------------------------------------------------------------------
316 Thunk info tables
317 -------------------------------------------------------------------------- */
318
319 /*
320 * When info tables are laid out backwards, we can omit the SRT
321 * pointer iff srt_bitmap is zero.
322 */
323
324 typedef struct StgThunkInfoTable_ {
325 #if !defined(TABLES_NEXT_TO_CODE)
326 StgInfoTable i;
327 #endif
328 #if defined(TABLES_NEXT_TO_CODE)
329 OFFSET_FIELD( srt_offset ); /* offset to the SRT table */
330 #else
331 StgSRT *srt; /* pointer to the SRT table */
332 #endif
333 #if defined(TABLES_NEXT_TO_CODE)
334 StgInfoTable i;
335 #endif
336 } StgThunkInfoTable;
337
338 /* -----------------------------------------------------------------------------
339 Constructor info tables
340 -------------------------------------------------------------------------- */
341
342 typedef struct StgConInfoTable_ {
343 #if !defined(TABLES_NEXT_TO_CODE)
344 StgInfoTable i;
345 #endif
346
347 #if defined(TABLES_NEXT_TO_CODE)
348 OFFSET_FIELD(con_desc) // the name of the data constructor
349 // as: Package:Module.Name
350 #else
351 char *con_desc;
352 #endif
353
354 #if defined(TABLES_NEXT_TO_CODE)
355 StgInfoTable i;
356 #endif
357 } StgConInfoTable;
358
359
360 /* -----------------------------------------------------------------------------
361 Accessor macros for fields that might be offsets (C version)
362 -------------------------------------------------------------------------- */
363
364 /*
365 * GET_SRT(info)
366 * info must be a Stg[Ret|Thunk]InfoTable* (an info table that has a SRT)
367 */
368 #ifdef TABLES_NEXT_TO_CODE
369 #define GET_SRT(info) ((StgSRT*) (((StgWord) ((info)+1)) + (info)->srt_offset))
370 #else
371 #define GET_SRT(info) ((info)->srt)
372 #endif
373
374 /*
375 * GET_CON_DESC(info)
376 * info must be a StgConInfoTable*.
377 */
378 #ifdef TABLES_NEXT_TO_CODE
379 #define GET_CON_DESC(info) ((char *)((StgWord)((info)+1) + (info->con_desc)))
380 #else
381 #define GET_CON_DESC(info) ((info)->con_desc)
382 #endif
383
384 /*
385 * GET_FUN_SRT(info)
386 * info must be a StgFunInfoTable*
387 */
388 #ifdef TABLES_NEXT_TO_CODE
389 #define GET_FUN_SRT(info) ((StgSRT*) (((StgWord) ((info)+1)) + (info)->f.srt_offset))
390 #else
391 #define GET_FUN_SRT(info) ((info)->f.srt)
392 #endif
393
394 #ifdef TABLES_NEXT_TO_CODE
395 #define GET_LARGE_BITMAP(info) ((StgLargeBitmap*) (((StgWord) ((info)+1)) \
396 + (info)->layout.large_bitmap_offset))
397 #else
398 #define GET_LARGE_BITMAP(info) ((info)->layout.large_bitmap)
399 #endif
400
401 #ifdef TABLES_NEXT_TO_CODE
402 #define GET_FUN_LARGE_BITMAP(info) ((StgLargeBitmap*) (((StgWord) ((info)+1)) \
403 + (info)->f.b.bitmap_offset))
404 #else
405 #define GET_FUN_LARGE_BITMAP(info) ((StgLargeBitmap*) ((info)->f.b.bitmap))
406 #endif
407
408 /*
409 * GET_PROF_TYPE, GET_PROF_DESC
410 */
411 #ifdef TABLES_NEXT_TO_CODE
412 #define GET_PROF_TYPE(info) ((char *)((StgWord)((info)+1) + (info->prof.closure_type_off)))
413 #else
414 #define GET_PROF_TYPE(info) ((info)->prof.closure_type)
415 #endif
416 #ifdef TABLES_NEXT_TO_CODE
417 #define GET_PROF_DESC(info) ((char *)((StgWord)((info)+1) + (info->prof.closure_desc_off)))
418 #else
419 #define GET_PROF_DESC(info) ((info)->prof.closure_desc)
420 #endif
421
422 #endif /* RTS_STORAGE_INFOTABLES_H */