1 /* -----------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2004
5 * Registers in the STG machine.
7 * The STG machine has a collection of "registers", each one of which
8 * may or may not correspond to an actual machine register when
11 * The register set is backed by a table in memory (struct
12 * StgRegTable). If a particular STG register is not mapped to a
13 * machine register, then the apprpriate slot in this table is used
16 * This table is itself pointed to by another register, BaseReg. If
17 * BaseReg is not in a machine register, then the register table is
18 * used from an absolute location (MainCapability).
20 * ---------------------------------------------------------------------------*/
26 StgWord stgEagerBlackholeInfo;
27 StgFunPtr stgGCEnter1;
32 * Vanilla registers are given this union type, which is purely so
33 * that we can cast the vanilla reg to a variety of types with the
34 * minimum of syntax. eg. R1.w instead of (StgWord)R1.
45 StgStackOffset offset; /* unused? */
51 * This is the table that holds shadow-locations for all the STG
52 * registers. The shadow locations are used when:
54 * 1) the particular register isn't mapped to a real machine
55 * register, probably because there's a shortage of real registers.
56 * 2) caller-saves registers are saved across a CCall
58 typedef struct StgRegTable_ {
67 StgUnion rR9; /* used occasionally by heap/stack checks */
68 StgUnion rR10; /* used occasionally by heap/stack checks */
80 struct StgTSO_ *rCurrentTSO;
81 struct step_ *rNursery;
82 struct bdescr_ *rCurrentNursery; /* Hp/HpLim point into this block */
83 struct bdescr_ *rCurrentAlloc; /* for allocation using allocate() */
84 StgWord rHpAlloc; /* number of *bytes* being allocated in heap */
85 StgWord rRet; // holds the return code of the thread
91 * Registers Hp and HpLim are global across the entire system, and are
92 * copied into the RegTable before executing a thread.
94 * Registers Sp and SpLim are saved in the TSO for the
95 * thread, but are copied into the RegTable before executing a thread.
97 * All other registers are "general purpose", and are used for passing
98 * arguments to functions, and returning values. The code generator
99 * knows how many of these are in real registers, and avoids
100 * generating code that uses non-real registers. General purpose
101 * registers are never saved when returning to the scheduler, instead
102 * we save whatever is live at the time on the stack, and restore it
103 * later. This should reduce the context switch time, amongst other
106 * For argument passing, the stack will be used in preference to
107 * pseudo-registers if the architecture has too few general purpose
110 * Some special RTS functions like newArray and the Integer primitives
111 * expect their arguments to be in registers R1-Rn, so we use these
112 * (pseudo-)registers in those cases.
116 * Locations for saving per-thread registers.
119 #define SAVE_Sp (CurrentTSO->sp)
120 #define SAVE_SpLim (CurrentTSO->splim)
122 #define SAVE_Hp (BaseReg->rHp)
124 #define SAVE_CurrentTSO (BaseReg->rCurrentTSO)
125 #define SAVE_CurrentNursery (BaseReg->rCurrentNursery)
126 #define SAVE_HpAlloc (BaseReg->rHpAlloc)
128 /* We sometimes need to save registers across a C-call, eg. if they
129 * are clobbered in the standard calling convention. We define the
130 * save locations for all registers in the register table.
133 #define SAVE_R1 (BaseReg->rR1)
134 #define SAVE_R2 (BaseReg->rR2)
135 #define SAVE_R3 (BaseReg->rR3)
136 #define SAVE_R4 (BaseReg->rR4)
137 #define SAVE_R5 (BaseReg->rR5)
138 #define SAVE_R6 (BaseReg->rR6)
139 #define SAVE_R7 (BaseReg->rR7)
140 #define SAVE_R8 (BaseReg->rR8)
142 #define SAVE_F1 (BaseReg->rF1)
143 #define SAVE_F2 (BaseReg->rF2)
144 #define SAVE_F3 (BaseReg->rF3)
145 #define SAVE_F4 (BaseReg->rF4)
147 #define SAVE_D1 (BaseReg->rD1)
148 #define SAVE_D2 (BaseReg->rD2)
150 #define SAVE_L1 (BaseReg->rL1)
152 /* -----------------------------------------------------------------------------
153 * Emit the GCC-specific register declarations for each machine
154 * register being used. If any STG register isn't mapped to a machine
155 * register, then map it to an offset from BaseReg.
157 * First, the general purpose registers. The idea is, if a particular
158 * general-purpose STG register can't be mapped to a real machine
159 * register, it won't be used at all. Instead, we'll use the stack.
161 * This is an improvement on the way things used to be done, when all
162 * registers were mapped to locations in the register table, and stuff
163 * was being shifted from the stack to the register table and back
164 * again for no good reason (on register-poor architectures).
167 /* define NO_REGS to omit register declarations - used in RTS C code
168 * that needs all the STG definitions but not the global register
171 #define GLOBAL_REG_DECL(type,name,reg) register type name REG(reg);
173 #if defined(REG_R1) && !defined(NO_GLOBAL_REG_DECLS)
174 GLOBAL_REG_DECL(StgUnion,R1,REG_R1)
176 # define R1 (BaseReg->rR1)
179 #if defined(REG_R2) && !defined(NO_GLOBAL_REG_DECLS)
180 GLOBAL_REG_DECL(StgUnion,R2,REG_R2)
182 # define R2 (BaseReg->rR2)
185 #if defined(REG_R3) && !defined(NO_GLOBAL_REG_DECLS)
186 GLOBAL_REG_DECL(StgUnion,R3,REG_R3)
188 # define R3 (BaseReg->rR3)
191 #if defined(REG_R4) && !defined(NO_GLOBAL_REG_DECLS)
192 GLOBAL_REG_DECL(StgUnion,R4,REG_R4)
194 # define R4 (BaseReg->rR4)
197 #if defined(REG_R5) && !defined(NO_GLOBAL_REG_DECLS)
198 GLOBAL_REG_DECL(StgUnion,R5,REG_R5)
200 # define R5 (BaseReg->rR5)
203 #if defined(REG_R6) && !defined(NO_GLOBAL_REG_DECLS)
204 GLOBAL_REG_DECL(StgUnion,R6,REG_R6)
206 # define R6 (BaseReg->rR6)
209 #if defined(REG_R7) && !defined(NO_GLOBAL_REG_DECLS)
210 GLOBAL_REG_DECL(StgUnion,R7,REG_R7)
212 # define R7 (BaseReg->rR7)
215 #if defined(REG_R8) && !defined(NO_GLOBAL_REG_DECLS)
216 GLOBAL_REG_DECL(StgUnion,R8,REG_R8)
218 # define R8 (BaseReg->rR8)
221 #if defined(REG_R9) && !defined(NO_GLOBAL_REG_DECLS)
222 GLOBAL_REG_DECL(StgUnion,R9,REG_R9)
224 # define R9 (BaseReg->rR9)
227 #if defined(REG_R10) && !defined(NO_GLOBAL_REG_DECLS)
228 GLOBAL_REG_DECL(StgUnion,R10,REG_R10)
230 # define R10 (BaseReg->rR10)
233 #if defined(REG_F1) && !defined(NO_GLOBAL_REG_DECLS)
234 GLOBAL_REG_DECL(StgFloat,F1,REG_F1)
236 #define F1 (BaseReg->rF1)
239 #if defined(REG_F2) && !defined(NO_GLOBAL_REG_DECLS)
240 GLOBAL_REG_DECL(StgFloat,F2,REG_F2)
242 #define F2 (BaseReg->rF2)
245 #if defined(REG_F3) && !defined(NO_GLOBAL_REG_DECLS)
246 GLOBAL_REG_DECL(StgFloat,F3,REG_F3)
248 #define F3 (BaseReg->rF3)
251 #if defined(REG_F4) && !defined(NO_GLOBAL_REG_DECLS)
252 GLOBAL_REG_DECL(StgFloat,F4,REG_F4)
254 #define F4 (BaseReg->rF4)
257 #if defined(REG_D1) && !defined(NO_GLOBAL_REG_DECLS)
258 GLOBAL_REG_DECL(StgDouble,D1,REG_D1)
260 #define D1 (BaseReg->rD1)
263 #if defined(REG_D2) && !defined(NO_GLOBAL_REG_DECLS)
264 GLOBAL_REG_DECL(StgDouble,D2,REG_D2)
266 #define D2 (BaseReg->rD2)
269 #if defined(REG_L1) && !defined(NO_GLOBAL_REG_DECLS)
270 GLOBAL_REG_DECL(StgWord64,L1,REG_L1)
272 #define L1 (BaseReg->rL1)
276 * If BaseReg isn't mapped to a machine register, just use the global
277 * address of the current register table (CurrentRegTable in
278 * concurrent Haskell, MainRegTable otherwise).
281 /* A capability is a combination of a FunTable and a RegTable. In STG
282 * code, BaseReg normally points to the RegTable portion of this
283 * structure, so that we can index both forwards and backwards to take
284 * advantage of shorter instruction forms on some archs (eg. x86).
285 * This is a cut-down version of the Capability structure; the full
286 * version is defined in Capability.h.
288 struct PartCapability_ {
293 /* No such thing as a MainCapability under THREADED_RTS - each thread must have
294 * its own Capability.
296 #if IN_STG_CODE && !(defined(THREADED_RTS) && !defined(NOSMP))
297 extern W_ MainCapability[];
301 * Assigning to BaseReg (the ASSIGN_BaseReg macro): this happens on
302 * return from a "safe" foreign call, when the thread might be running
303 * on a new Capability. Obviously if BaseReg is not a register, then
304 * we are restricted to a single Capability (this invariant is enforced
305 * in Capability.c:initCapabilities), and assigning to BaseReg can be omitted.
308 #if defined(REG_Base) && !defined(NO_GLOBAL_REG_DECLS)
309 GLOBAL_REG_DECL(StgRegTable *,BaseReg,REG_Base)
310 #define ASSIGN_BaseReg(e) (BaseReg = (e))
312 #if defined(THREADED_RTS) && !defined(NOSMP)
313 #error BaseReg must be in a register for THREADED_RTS
315 #define BaseReg (&((struct PartCapability_ *)MainCapability)->r)
316 #define ASSIGN_BaseReg(e) (e)
319 #if defined(REG_Sp) && !defined(NO_GLOBAL_REG_DECLS)
320 GLOBAL_REG_DECL(P_,Sp,REG_Sp)
322 #define Sp (BaseReg->rSp)
325 #if defined(REG_SpLim) && !defined(NO_GLOBAL_REG_DECLS)
326 GLOBAL_REG_DECL(P_,SpLim,REG_SpLim)
328 #define SpLim (BaseReg->rSpLim)
331 #if defined(REG_Hp) && !defined(NO_GLOBAL_REG_DECLS)
332 GLOBAL_REG_DECL(P_,Hp,REG_Hp)
334 #define Hp (BaseReg->rHp)
337 #if defined(REG_HpLim) && !defined(NO_GLOBAL_REG_DECLS)
338 #error HpLim cannot be in a register
340 #define HpLim (BaseReg->rHpLim)
343 #if defined(REG_CurrentTSO) && !defined(NO_GLOBAL_REG_DECLS)
344 GLOBAL_REG_DECL(struct _StgTSO *,CurrentTSO,REG_CurrentTSO)
346 #define CurrentTSO (BaseReg->rCurrentTSO)
349 #if defined(REG_CurrentNursery) && !defined(NO_GLOBAL_REG_DECLS)
350 GLOBAL_REG_DECL(bdescr *,CurrentNursery,REG_CurrentNursery)
352 #define CurrentNursery (BaseReg->rCurrentNursery)
355 #if defined(REG_HpAlloc) && !defined(NO_GLOBAL_REG_DECLS)
356 GLOBAL_REG_DECL(bdescr *,HpAlloc,REG_HpAlloc)
358 #define HpAlloc (BaseReg->rHpAlloc)
361 /* -----------------------------------------------------------------------------
362 Get absolute function pointers from the register table, to save
371 as long as the offset is within the range of a signed byte
372 (-128..+127). So we pick some common absolute_addresses and put
373 them in the register table. As a bonus, linking time should also
376 Other possible candidates in order of importance:
379 stg_CAF_BLACKHOLE_info
382 anything else probably isn't worth the effort.
384 -------------------------------------------------------------------------- */
387 #define FunReg ((StgFunTable *)((void *)BaseReg - STG_FIELD_OFFSET(struct PartCapability_, r)))
389 #define stg_EAGER_BLACKHOLE_info (FunReg->stgEagerBlackholeInfo)
390 #define stg_gc_enter_1 (FunReg->stgGCEnter1)
391 #define stg_gc_fun (FunReg->stgGCFun)
393 /* -----------------------------------------------------------------------------
394 For any registers which are denoted "caller-saves" by the C calling
395 convention, we have to emit code to save and restore them across C
397 -------------------------------------------------------------------------- */
399 #ifdef CALLER_SAVES_R1
400 #define CALLER_SAVE_R1 SAVE_R1 = R1;
401 #define CALLER_RESTORE_R1 R1 = SAVE_R1;
403 #define CALLER_SAVE_R1 /* nothing */
404 #define CALLER_RESTORE_R1 /* nothing */
407 #ifdef CALLER_SAVES_R2
408 #define CALLER_SAVE_R2 SAVE_R2 = R2;
409 #define CALLER_RESTORE_R2 R2 = SAVE_R2;
411 #define CALLER_SAVE_R2 /* nothing */
412 #define CALLER_RESTORE_R2 /* nothing */
415 #ifdef CALLER_SAVES_R3
416 #define CALLER_SAVE_R3 SAVE_R3 = R3;
417 #define CALLER_RESTORE_R3 R3 = SAVE_R3;
419 #define CALLER_SAVE_R3 /* nothing */
420 #define CALLER_RESTORE_R3 /* nothing */
423 #ifdef CALLER_SAVES_R4
424 #define CALLER_SAVE_R4 SAVE_R4 = R4;
425 #define CALLER_RESTORE_R4 R4 = SAVE_R4;
427 #define CALLER_SAVE_R4 /* nothing */
428 #define CALLER_RESTORE_R4 /* nothing */
431 #ifdef CALLER_SAVES_R5
432 #define CALLER_SAVE_R5 SAVE_R5 = R5;
433 #define CALLER_RESTORE_R5 R5 = SAVE_R5;
435 #define CALLER_SAVE_R5 /* nothing */
436 #define CALLER_RESTORE_R5 /* nothing */
439 #ifdef CALLER_SAVES_R6
440 #define CALLER_SAVE_R6 SAVE_R6 = R6;
441 #define CALLER_RESTORE_R6 R6 = SAVE_R6;
443 #define CALLER_SAVE_R6 /* nothing */
444 #define CALLER_RESTORE_R6 /* nothing */
447 #ifdef CALLER_SAVES_R7
448 #define CALLER_SAVE_R7 SAVE_R7 = R7;
449 #define CALLER_RESTORE_R7 R7 = SAVE_R7;
451 #define CALLER_SAVE_R7 /* nothing */
452 #define CALLER_RESTORE_R7 /* nothing */
455 #ifdef CALLER_SAVES_R8
456 #define CALLER_SAVE_R8 SAVE_R8 = R8;
457 #define CALLER_RESTORE_R8 R8 = SAVE_R8;
459 #define CALLER_SAVE_R8 /* nothing */
460 #define CALLER_RESTORE_R8 /* nothing */
463 #ifdef CALLER_SAVES_R9
464 #define CALLER_SAVE_R9 SAVE_R9 = R9;
465 #define CALLER_RESTORE_R9 R9 = SAVE_R9;
467 #define CALLER_SAVE_R9 /* nothing */
468 #define CALLER_RESTORE_R9 /* nothing */
471 #ifdef CALLER_SAVES_R10
472 #define CALLER_SAVE_R10 SAVE_R10 = R10;
473 #define CALLER_RESTORE_R10 R10 = SAVE_R10;
475 #define CALLER_SAVE_R10 /* nothing */
476 #define CALLER_RESTORE_R10 /* nothing */
479 #ifdef CALLER_SAVES_F1
480 #define CALLER_SAVE_F1 SAVE_F1 = F1;
481 #define CALLER_RESTORE_F1 F1 = SAVE_F1;
483 #define CALLER_SAVE_F1 /* nothing */
484 #define CALLER_RESTORE_F1 /* nothing */
487 #ifdef CALLER_SAVES_F2
488 #define CALLER_SAVE_F2 SAVE_F2 = F2;
489 #define CALLER_RESTORE_F2 F2 = SAVE_F2;
491 #define CALLER_SAVE_F2 /* nothing */
492 #define CALLER_RESTORE_F2 /* nothing */
495 #ifdef CALLER_SAVES_F3
496 #define CALLER_SAVE_F3 SAVE_F3 = F3;
497 #define CALLER_RESTORE_F3 F3 = SAVE_F3;
499 #define CALLER_SAVE_F3 /* nothing */
500 #define CALLER_RESTORE_F3 /* nothing */
503 #ifdef CALLER_SAVES_F4
504 #define CALLER_SAVE_F4 SAVE_F4 = F4;
505 #define CALLER_RESTORE_F4 F4 = SAVE_F4;
507 #define CALLER_SAVE_F4 /* nothing */
508 #define CALLER_RESTORE_F4 /* nothing */
511 #ifdef CALLER_SAVES_D1
512 #define CALLER_SAVE_D1 SAVE_D1 = D1;
513 #define CALLER_RESTORE_D1 D1 = SAVE_D1;
515 #define CALLER_SAVE_D1 /* nothing */
516 #define CALLER_RESTORE_D1 /* nothing */
519 #ifdef CALLER_SAVES_D2
520 #define CALLER_SAVE_D2 SAVE_D2 = D2;
521 #define CALLER_RESTORE_D2 D2 = SAVE_D2;
523 #define CALLER_SAVE_D2 /* nothing */
524 #define CALLER_RESTORE_D2 /* nothing */
527 #ifdef CALLER_SAVES_L1
528 #define CALLER_SAVE_L1 SAVE_L1 = L1;
529 #define CALLER_RESTORE_L1 L1 = SAVE_L1;
531 #define CALLER_SAVE_L1 /* nothing */
532 #define CALLER_RESTORE_L1 /* nothing */
535 #ifdef CALLER_SAVES_Sp
536 #define CALLER_SAVE_Sp SAVE_Sp = Sp;
537 #define CALLER_RESTORE_Sp Sp = SAVE_Sp;
539 #define CALLER_SAVE_Sp /* nothing */
540 #define CALLER_RESTORE_Sp /* nothing */
543 #ifdef CALLER_SAVES_SpLim
544 #define CALLER_SAVE_SpLim SAVE_SpLim = SpLim;
545 #define CALLER_RESTORE_SpLim SpLim = SAVE_SpLim;
547 #define CALLER_SAVE_SpLim /* nothing */
548 #define CALLER_RESTORE_SpLim /* nothing */
551 #ifdef CALLER_SAVES_Hp
552 #define CALLER_SAVE_Hp SAVE_Hp = Hp;
553 #define CALLER_RESTORE_Hp Hp = SAVE_Hp;
555 #define CALLER_SAVE_Hp /* nothing */
556 #define CALLER_RESTORE_Hp /* nothing */
559 #ifdef CALLER_SAVES_Base
561 #error "Can't have caller-saved BaseReg with THREADED_RTS"
563 #define CALLER_SAVE_Base /* nothing */
564 #define CALLER_RESTORE_Base BaseReg = &MainRegTable;
566 #define CALLER_SAVE_Base /* nothing */
567 #define CALLER_RESTORE_Base /* nothing */
570 #ifdef CALLER_SAVES_CurrentTSO
571 #define CALLER_SAVE_CurrentTSO SAVE_CurrentTSO = CurrentTSO;
572 #define CALLER_RESTORE_CurrentTSO CurrentTSO = SAVE_CurrentTSO;
574 #define CALLER_SAVE_CurrentTSO /* nothing */
575 #define CALLER_RESTORE_CurrentTSO /* nothing */
578 #ifdef CALLER_SAVES_CurrentNursery
579 #define CALLER_SAVE_CurrentNursery SAVE_CurrentNursery = CurrentNursery;
580 #define CALLER_RESTORE_CurrentNursery CurrentNursery = SAVE_CurrentNursery;
582 #define CALLER_SAVE_CurrentNursery /* nothing */
583 #define CALLER_RESTORE_CurrentNursery /* nothing */
586 #ifdef CALLER_SAVES_HpAlloc
587 #define CALLER_SAVE_HpAlloc SAVE_HpAlloc = HpAlloc;
588 #define CALLER_RESTORE_HpAlloc HpAlloc = SAVE_HpAlloc;
590 #define CALLER_SAVE_HpAlloc /* nothing */
591 #define CALLER_RESTORE_HpAlloc /* nothing */
594 #endif /* IN_STG_CODE */
596 /* ----------------------------------------------------------------------------
597 Handy bunches of saves/restores
598 ------------------------------------------------------------------------ */
602 #define CALLER_SAVE_USER \
619 /* Save Base last, since the others may
620 be addressed relative to it */
621 #define CALLER_SAVE_SYSTEM \
625 CALLER_SAVE_CurrentTSO \
626 CALLER_SAVE_CurrentNursery \
629 #define CALLER_RESTORE_USER \
646 /* Restore Base first, since the others may
647 be addressed relative to it */
648 #define CALLER_RESTORE_SYSTEM \
649 CALLER_RESTORE_Base \
651 CALLER_RESTORE_SpLim \
653 CALLER_RESTORE_CurrentTSO \
654 CALLER_RESTORE_CurrentNursery
656 #else /* not IN_STG_CODE */
658 #define CALLER_SAVE_USER /* nothing */
659 #define CALLER_SAVE_SYSTEM /* nothing */
660 #define CALLER_RESTORE_USER /* nothing */
661 #define CALLER_RESTORE_SYSTEM /* nothing */
663 #endif /* IN_STG_CODE */
664 #define CALLER_SAVE_ALL \
668 #define CALLER_RESTORE_ALL \
669 CALLER_RESTORE_SYSTEM \