summaryrefslogtreecommitdiff
path: root/rts/Compact.cmm
blob: 061646846d612c93bb5797bfcea48535bcb731f7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
/* -----------------------------------------------------------------------------
 *
 * (c) The GHC Team, 2015-2016
 *
 * Support for compact regions.  See Note [Compact Normal Forms] in
 * rts/sm/CNF.c
 *
 * ---------------------------------------------------------------------------*/

#include "Cmm.h"
#include "sm/ShouldCompact.h"

import CLOSURE base_GHCziIOziException_cannotCompactFunction_closure;
import CLOSURE base_GHCziIOziException_cannotCompactMutable_closure;
import CLOSURE base_GHCziIOziException_cannotCompactPinned_closure;

//
// Allocate space for a new object in the compact region.  We first try
// the fast method using the hp/hpLim fields of StgCompactNFData, and
// if that fails we fall back to calling allocateForCompact() which
// will append a new block if necessary.
//
#define ALLOCATE(compact,sizeW,p,to, tag)                               \
    hp = StgCompactNFData_hp(compact);                                  \
    if (hp + WDS(sizeW) <= StgCompactNFData_hpLim(compact)) {           \
        to = hp;                                                        \
        StgCompactNFData_hp(compact) = hp + WDS(sizeW);                 \
    } else {                                                            \
        ("ptr" to) = ccall allocateForCompact(                          \
            MyCapability() "ptr", compact "ptr", sizeW);                \
    }                                                                   \
    if (StgCompactNFData_hash(compact) != NULL) {                       \
        ccall insertCompactHash(MyCapability(), compact, p, tag | to);  \
    }


//
// Look up a pointer in the hash table if we're doing sharing.
//
#define CHECK_HASH()                                                    \
    hash = StgCompactNFData_hash(compact);                              \
    if (hash != NULL) {                                                 \
        ("ptr" hashed) = ccall lookupHashTable(hash "ptr", p "ptr");    \
        if (hashed != NULL) {                                           \
            P_[pp] = hashed;                                            \
            return ();                                                  \
        }                                                               \
    }

//
// Evacuate and copy an object and its transitive closure into a
// compact.  This function is called recursively as we traverse the
// data structure.  It takes the location to store the address of the
// compacted object as an argument, so that it can be tail-recursive.
//
stg_compactAddWorkerzh (
    P_ compact,  // The Compact# object
    P_ p,        // The object to compact
    W_ pp)       // Where to store a pointer to the compacted object
{
    W_ type, info, should, hash, hp, tag;
    P_ p;
    P_ hashed;

    again: MAYBE_GC(again);
    STK_CHK_GEN();

eval:
    tag = GETTAG(p);
    p = UNTAG(p);
    info  = %INFO_PTR(p);
    type = TO_W_(%INFO_TYPE(%STD_INFO(info)));

    switch [0 .. N_CLOSURE_TYPES] type {

    // Unevaluated things must be evaluated first:
    case
        THUNK,
        THUNK_1_0,
        THUNK_0_1,
        THUNK_2_0,
        THUNK_1_1,
        THUNK_0_2,
        THUNK_STATIC,
        AP,
        AP_STACK,
        BLACKHOLE,
        THUNK_SELECTOR : {
        (P_ evald) = call %ENTRY_CODE(info) (p);
        p = evald;
        goto eval;
    }

    // Follow indirections:
    case IND, IND_STATIC: {
        p = StgInd_indirectee(p);
        goto eval;
    }

    // Mutable things are not allowed:
    case
        MVAR_CLEAN,
        MVAR_DIRTY,
        TVAR,
        MUT_ARR_PTRS_CLEAN,
        MUT_ARR_PTRS_DIRTY,
        MUT_ARR_PTRS_CLEAN,
        MUT_VAR_CLEAN,
        MUT_VAR_DIRTY,
        WEAK,
        PRIM,
        MUT_PRIM,
        TSO,
        STACK,
        TREC_CHUNK,
        WHITEHOLE,
        SMALL_MUT_ARR_PTRS_CLEAN,
        SMALL_MUT_ARR_PTRS_DIRTY,
        COMPACT_NFDATA: {
        jump stg_raisezh(base_GHCziIOziException_cannotCompactMutable_closure);
    }

    // We shouldn't see any functions, if this data structure was NFData.
    case
        FUN,
        FUN_1_0,
        FUN_0_1,
        FUN_2_0,
        FUN_1_1,
        FUN_0_2,
        FUN_STATIC,
        BCO,
        PAP: {
        jump stg_raisezh(base_GHCziIOziException_cannotCompactFunction_closure);
    }

    case ARR_WORDS: {

        (should) = ccall shouldCompact(compact "ptr", p "ptr");
        if (should == SHOULDCOMPACT_IN_CNF) { P_[pp] = p; return(); }
        if (should == SHOULDCOMPACT_PINNED) {
            jump stg_raisezh(base_GHCziIOziException_cannotCompactPinned_closure);
        }

        CHECK_HASH();

        P_ to;
        W_ size;
        size = SIZEOF_StgArrBytes + StgArrBytes_bytes(p);
        ALLOCATE(compact, ROUNDUP_BYTES_TO_WDS(size), p, to, tag);
        P_[pp] = to;
        prim %memcpy(to, p, size, 1);
        return();
    }

    case
        MUT_ARR_PTRS_FROZEN_DIRTY,
        MUT_ARR_PTRS_FROZEN_CLEAN: {

        (should) = ccall shouldCompact(compact "ptr", p "ptr");
        if (should == SHOULDCOMPACT_IN_CNF) { P_[pp] = p; return(); }

        CHECK_HASH();

        W_ i, size, cards, ptrs;
        size = SIZEOF_StgMutArrPtrs + WDS(StgMutArrPtrs_size(p));
        ptrs = StgMutArrPtrs_ptrs(p);
        cards = SIZEOF_StgMutArrPtrs + WDS(ptrs);
        ALLOCATE(compact, BYTES_TO_WDS(size), p, to, tag);
        P_[pp] = tag | to;
        SET_HDR(to, StgHeader_info(p), StgHeader_ccs(p));
        StgMutArrPtrs_ptrs(to) = ptrs;
        StgMutArrPtrs_size(to) = StgMutArrPtrs_size(p);
        prim %memcpy(to + cards, p + cards , size - cards, 1);
        i = 0;
      loop0:
        if (i < ptrs) ( likely: True ) {
            W_ q;
            q = to + SIZEOF_StgMutArrPtrs + WDS(i);
            call stg_compactAddWorkerzh(
                compact, P_[p + SIZEOF_StgMutArrPtrs + WDS(i)], q);
            i = i + 1;
            goto loop0;
        }
        return();
    }

    case
        SMALL_MUT_ARR_PTRS_FROZEN_DIRTY,
        SMALL_MUT_ARR_PTRS_FROZEN_CLEAN: {

        (should) = ccall shouldCompact(compact "ptr", p "ptr");
        if (should == SHOULDCOMPACT_IN_CNF) { P_[pp] = p; return(); }

        CHECK_HASH();

        W_ i, ptrs;
        ptrs = StgSmallMutArrPtrs_ptrs(p);
        ALLOCATE(compact, BYTES_TO_WDS(SIZEOF_StgSmallMutArrPtrs) + ptrs, p, to, tag);
        P_[pp] = tag | to;
        SET_HDR(to, StgHeader_info(p), StgHeader_ccs(p));
        StgSmallMutArrPtrs_ptrs(to) = ptrs;
        i = 0;
      loop1:
        if (i < ptrs) ( likely: True ) {
            W_ q;
            q = to + SIZEOF_StgSmallMutArrPtrs + WDS(i);
            call stg_compactAddWorkerzh(
                compact, P_[p + SIZEOF_StgSmallMutArrPtrs + WDS(i)], q);
            i = i + 1;
            goto loop1;
        }
        return();
    }

    // Everything else we should copy and evaluate the components:
    case
        CONSTR,
        CONSTR_1_0,
        CONSTR_2_0,
        CONSTR_1_1: {

        (should) = ccall shouldCompact(compact "ptr", p "ptr");
        if (should == SHOULDCOMPACT_IN_CNF) { P_[pp] = p; return(); }

      constructor:

        CHECK_HASH();

        W_ i, ptrs, nptrs, size;
        P_ to;
        ptrs  = TO_W_(%INFO_PTRS(%STD_INFO(info)));
        nptrs  = TO_W_(%INFO_NPTRS(%STD_INFO(info)));
        size = BYTES_TO_WDS(SIZEOF_StgHeader) + ptrs + nptrs;

        ALLOCATE(compact, size, p, to, tag);
        P_[pp] = tag | to;
        SET_HDR(to, StgHeader_info(p), StgHeader_ccs(p));

        // First, copy the non-pointers
        if (nptrs > 0) {
            i = ptrs;
        loop2:
            StgClosure_payload(to,i) = StgClosure_payload(p,i);
            i = i + 1;
            if (i < ptrs + nptrs) ( likely: True ) goto loop2;
        }

        // Next, recursively compact and copy the pointers
        if (ptrs == 0) { return(); }
        i = 0;
      loop3:
        W_ q;
        q = to + SIZEOF_StgHeader + OFFSET_StgClosure_payload + WDS(i);
        // Tail-call the last one.  This means we don't build up a deep
        // stack when compacting lists.
        if (i == ptrs - 1) {
            jump stg_compactAddWorkerzh(compact, StgClosure_payload(p,i), q);
        }
        call stg_compactAddWorkerzh(compact, StgClosure_payload(p,i), q);
        i = i + 1;
        goto loop3;
    }

    // these might be static closures that we can avoid copying into
    // the compact if they don't refer to CAFs.
    case
        CONSTR_0_1,
        CONSTR_0_2,
        CONSTR_NOCAF: {

        (should) = ccall shouldCompact(compact "ptr", p "ptr");
        if (should == SHOULDCOMPACT_IN_CNF ||
            should == SHOULDCOMPACT_STATIC) { P_[pp] = p; return(); }

        goto constructor;
    }}

    ccall barf("stg_compactWorkerzh");
}

//
// compactAddWithSharing#
//   :: State# RealWorld
//   -> Compact#
//   -> a
//   -> (# State# RealWorld, a #)
//
stg_compactAddWithSharingzh (P_ compact, P_ p)
{
    W_ hash;
    ASSERT(StgCompactNFData_hash(compact) == NULL);
    (hash) = ccall allocHashTable();
    StgCompactNFData_hash(compact) = hash;

    // Note [compactAddWorker result]
    //
    // compactAddWorker needs somewhere to store the result - this is
    // so that it can be tail-recursive.  It must be an address that
    // doesn't move during GC, so we can't use heap or stack.
    // Therefore we have a special field in the StgCompactNFData
    // object to hold the final result of compaction.
    W_ pp;
    pp = compact + SIZEOF_StgHeader + OFFSET_StgCompactNFData_result;
    call stg_compactAddWorkerzh(compact, p, pp);
    ccall freeHashTable(StgCompactNFData_hash(compact), NULL);
    StgCompactNFData_hash(compact) = NULL;
#if defined(DEBUG)
    ccall verifyCompact(compact);
#endif
    return (P_[pp]);
}

//
// compactAdd#
//   :: State# RealWorld
//   -> Compact#
//   -> a
//   -> (# State# RealWorld, a #)
//
stg_compactAddzh (P_ compact, P_ p)
{
    ASSERT(StgCompactNFData_hash(compact) == NULL);

    W_ pp; // See Note [compactAddWorker result]
    pp = compact + SIZEOF_StgHeader + OFFSET_StgCompactNFData_result;
    call stg_compactAddWorkerzh(compact, p, pp);
#if defined(DEBUG)
    ccall verifyCompact(compact);
#endif
    return (P_[pp]);
}

stg_compactSizzezh (P_ compact)
{
   return (StgCompactNFData_totalW(compact) * SIZEOF_W);
}

stg_compactNewzh ( W_ size )
{
    P_ str;

    again: MAYBE_GC(again);

    ("ptr" str) = ccall compactNew(MyCapability() "ptr", size);
    return (str);
}

stg_compactResizzezh ( P_ str, W_ new_size )
{
    again: MAYBE_GC(again);

    ccall compactResize(MyCapability() "ptr", str "ptr", new_size);
    return ();
}

stg_compactContainszh ( P_ str, P_ val )
{
    W_ rval;

    (rval) = ccall compactContains(str "ptr", val "ptr");
    return (rval);
}

stg_compactContainsAnyzh ( P_ val )
{
    W_ rval;

    (rval) = ccall compactContains(0 "ptr", val "ptr");
    return (rval);
}

stg_compactGetFirstBlockzh ( P_ str )
{
    /* W_, not P_, because it is not a gc pointer */
    W_ block;
    W_ bd;
    W_ size;

    block = str - SIZEOF_StgCompactNFDataBlock::W_;
    ASSERT(StgCompactNFDataBlock_owner(block) == str);

    // We have to save Hp back to the nursery, otherwise the size will
    // be wrong.
    bd = Bdescr(StgCompactNFData_nursery(str));
    bdescr_free(bd) = StgCompactNFData_hp(str);

    bd = Bdescr(str);
    size = bdescr_free(bd) - bdescr_start(bd);
    ASSERT(size <= TO_W_(bdescr_blocks(bd)) * BLOCK_SIZE);

    return (block, size);
}

stg_compactGetNextBlockzh ( P_ str, W_ block )
{
    /* str is a pointer to the closure holding the Compact#
       it is there primarily to keep everything reachable from
       the GC: by having it on the stack of type P_, the GC will
       see all the blocks as live (any pointer in the Compact#
       keeps it alive), and will not collect the block
       We don't run a GC inside this primop, but it could
       happen right after, or we could be preempted.

       str is also useful for debugging, as it can be casted
       to a useful C struct from the gdb command line and all
       blocks can be inspected
    */
    W_ bd;
    W_ next_block;
    W_ size;

    next_block = StgCompactNFDataBlock_next(block);

    if (next_block == 0::W_) {
        return (0::W_, 0::W_);
    }

    ASSERT(StgCompactNFDataBlock_owner(next_block) == str ||
            StgCompactNFDataBlock_owner(next_block) == NULL);

    bd = Bdescr(next_block);
    size = bdescr_free(bd) - bdescr_start(bd);
    ASSERT(size <= TO_W_(bdescr_blocks(bd)) * BLOCK_SIZE);

    return (next_block, size);
}

stg_compactAllocateBlockzh ( W_ size, W_ previous )
{
    W_ actual_block;

    again: MAYBE_GC(again);

    ("ptr" actual_block) = ccall compactAllocateBlock(MyCapability(),
                                                      size,
                                                      previous "ptr");

    return (actual_block);
}

stg_compactFixupPointerszh ( W_ first_block, W_ root )
{
    W_ str;
    P_ gcstr;
    W_ ok;

    str = first_block + SIZEOF_StgCompactNFDataBlock::W_;
    (ok) = ccall compactFixupPointers (str "ptr", root "ptr");

    // Now we can let the GC know about str, because it was linked
    // into the generation list and the book-keeping pointers are
    // guaranteed to be valid
    // (this is true even if the fixup phase failed)
    gcstr = str;
    return (gcstr, ok);
}