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? */
50 // Urgh.. we don't know the size of an MP_INT here because we haven't
51 // #included gmp.h. We should really autoconf this, but GMP may not
52 // be available at ./configure time if we're building it (GMP) locally.
53 #define MP_INT_WORDS 3
56 * This is the table that holds shadow-locations for all the STG
57 * registers. The shadow locations are used when:
59 * 1) the particular register isn't mapped to a real machine
60 * register, probably because there's a shortage of real registers.
61 * 2) caller-saves registers are saved across a CCall
63 typedef struct StgRegTable_ {
72 StgUnion rR9; /* used occasionally by heap/stack checks */
73 StgUnion rR10; /* used occasionally by heap/stack checks */
85 struct StgTSO_ *rCurrentTSO;
86 struct step_ *rNursery;
87 struct bdescr_ *rCurrentNursery; /* Hp/HpLim point into this block */
88 struct bdescr_ *rCurrentAlloc; /* for allocation using allocate() */
89 StgWord rHpAlloc; /* number of *bytes* being allocated in heap */
90 // rmp_tmp1..rmp_result2 are only used in THREADED_RTS builds to
91 // avoid per-thread temps in bss, but currently always incldue here
92 // so we just run mkDerivedConstants once
93 StgWord rmp_tmp_w[MP_INT_WORDS];
94 StgWord rmp_tmp1[MP_INT_WORDS];
95 StgWord rmp_tmp2[MP_INT_WORDS];
96 StgWord rmp_result1[MP_INT_WORDS];
97 StgWord rmp_result2[MP_INT_WORDS];
98 StgWord rRet; // holds the return code of the thread
104 * Registers Hp and HpLim are global across the entire system, and are
105 * copied into the RegTable before executing a thread.
107 * Registers Sp and SpLim are saved in the TSO for the
108 * thread, but are copied into the RegTable before executing a thread.
110 * All other registers are "general purpose", and are used for passing
111 * arguments to functions, and returning values. The code generator
112 * knows how many of these are in real registers, and avoids
113 * generating code that uses non-real registers. General purpose
114 * registers are never saved when returning to the scheduler, instead
115 * we save whatever is live at the time on the stack, and restore it
116 * later. This should reduce the context switch time, amongst other
119 * For argument passing, the stack will be used in preference to
120 * pseudo-registers if the architecture has too few general purpose
123 * Some special RTS functions like newArray and the Integer primitives
124 * expect their arguments to be in registers R1-Rn, so we use these
125 * (pseudo-)registers in those cases.
129 * Locations for saving per-thread registers.
132 #define SAVE_Sp (CurrentTSO->sp)
133 #define SAVE_SpLim (CurrentTSO->splim)
135 #define SAVE_Hp (BaseReg->rHp)
137 #define SAVE_CurrentTSO (BaseReg->rCurrentTSO)
138 #define SAVE_CurrentNursery (BaseReg->rCurrentNursery)
139 #define SAVE_HpAlloc (BaseReg->rHpAlloc)
141 /* We sometimes need to save registers across a C-call, eg. if they
142 * are clobbered in the standard calling convention. We define the
143 * save locations for all registers in the register table.
146 #define SAVE_R1 (BaseReg->rR1)
147 #define SAVE_R2 (BaseReg->rR2)
148 #define SAVE_R3 (BaseReg->rR3)
149 #define SAVE_R4 (BaseReg->rR4)
150 #define SAVE_R5 (BaseReg->rR5)
151 #define SAVE_R6 (BaseReg->rR6)
152 #define SAVE_R7 (BaseReg->rR7)
153 #define SAVE_R8 (BaseReg->rR8)
155 #define SAVE_F1 (BaseReg->rF1)
156 #define SAVE_F2 (BaseReg->rF2)
157 #define SAVE_F3 (BaseReg->rF3)
158 #define SAVE_F4 (BaseReg->rF4)
160 #define SAVE_D1 (BaseReg->rD1)
161 #define SAVE_D2 (BaseReg->rD2)
163 #define SAVE_L1 (BaseReg->rL1)
165 /* -----------------------------------------------------------------------------
166 * Emit the GCC-specific register declarations for each machine
167 * register being used. If any STG register isn't mapped to a machine
168 * register, then map it to an offset from BaseReg.
170 * First, the general purpose registers. The idea is, if a particular
171 * general-purpose STG register can't be mapped to a real machine
172 * register, it won't be used at all. Instead, we'll use the stack.
174 * This is an improvement on the way things used to be done, when all
175 * registers were mapped to locations in the register table, and stuff
176 * was being shifted from the stack to the register table and back
177 * again for no good reason (on register-poor architectures).
180 /* define NO_REGS to omit register declarations - used in RTS C code
181 * that needs all the STG definitions but not the global register
184 #define GLOBAL_REG_DECL(type,name,reg) register type name REG(reg);
186 #if defined(REG_R1) && !defined(NO_GLOBAL_REG_DECLS)
187 GLOBAL_REG_DECL(StgUnion,R1,REG_R1)
189 # define R1 (BaseReg->rR1)
192 #if defined(REG_R2) && !defined(NO_GLOBAL_REG_DECLS)
193 GLOBAL_REG_DECL(StgUnion,R2,REG_R2)
195 # define R2 (BaseReg->rR2)
198 #if defined(REG_R3) && !defined(NO_GLOBAL_REG_DECLS)
199 GLOBAL_REG_DECL(StgUnion,R3,REG_R3)
201 # define R3 (BaseReg->rR3)
204 #if defined(REG_R4) && !defined(NO_GLOBAL_REG_DECLS)
205 GLOBAL_REG_DECL(StgUnion,R4,REG_R4)
207 # define R4 (BaseReg->rR4)
210 #if defined(REG_R5) && !defined(NO_GLOBAL_REG_DECLS)
211 GLOBAL_REG_DECL(StgUnion,R5,REG_R5)
213 # define R5 (BaseReg->rR5)
216 #if defined(REG_R6) && !defined(NO_GLOBAL_REG_DECLS)
217 GLOBAL_REG_DECL(StgUnion,R6,REG_R6)
219 # define R6 (BaseReg->rR6)
222 #if defined(REG_R7) && !defined(NO_GLOBAL_REG_DECLS)
223 GLOBAL_REG_DECL(StgUnion,R7,REG_R7)
225 # define R7 (BaseReg->rR7)
228 #if defined(REG_R8) && !defined(NO_GLOBAL_REG_DECLS)
229 GLOBAL_REG_DECL(StgUnion,R8,REG_R8)
231 # define R8 (BaseReg->rR8)
234 #if defined(REG_R9) && !defined(NO_GLOBAL_REG_DECLS)
235 GLOBAL_REG_DECL(StgUnion,R9,REG_R9)
237 # define R9 (BaseReg->rR9)
240 #if defined(REG_R10) && !defined(NO_GLOBAL_REG_DECLS)
241 GLOBAL_REG_DECL(StgUnion,R10,REG_R10)
243 # define R10 (BaseReg->rR10)
246 #if defined(REG_F1) && !defined(NO_GLOBAL_REG_DECLS)
247 GLOBAL_REG_DECL(StgFloat,F1,REG_F1)
249 #define F1 (BaseReg->rF1)
252 #if defined(REG_F2) && !defined(NO_GLOBAL_REG_DECLS)
253 GLOBAL_REG_DECL(StgFloat,F2,REG_F2)
255 #define F2 (BaseReg->rF2)
258 #if defined(REG_F3) && !defined(NO_GLOBAL_REG_DECLS)
259 GLOBAL_REG_DECL(StgFloat,F3,REG_F3)
261 #define F3 (BaseReg->rF3)
264 #if defined(REG_F4) && !defined(NO_GLOBAL_REG_DECLS)
265 GLOBAL_REG_DECL(StgFloat,F4,REG_F4)
267 #define F4 (BaseReg->rF4)
270 #if defined(REG_D1) && !defined(NO_GLOBAL_REG_DECLS)
271 GLOBAL_REG_DECL(StgDouble,D1,REG_D1)
273 #define D1 (BaseReg->rD1)
276 #if defined(REG_D2) && !defined(NO_GLOBAL_REG_DECLS)
277 GLOBAL_REG_DECL(StgDouble,D2,REG_D2)
279 #define D2 (BaseReg->rD2)
282 #if defined(REG_L1) && !defined(NO_GLOBAL_REG_DECLS)
283 GLOBAL_REG_DECL(StgWord64,L1,REG_L1)
285 #define L1 (BaseReg->rL1)
289 * If BaseReg isn't mapped to a machine register, just use the global
290 * address of the current register table (CurrentRegTable in
291 * concurrent Haskell, MainRegTable otherwise).
294 /* A capability is a combination of a FunTable and a RegTable. In STG
295 * code, BaseReg normally points to the RegTable portion of this
296 * structure, so that we can index both forwards and backwards to take
297 * advantage of shorter instruction forms on some archs (eg. x86).
298 * This is a cut-down version of the Capability structure; the full
299 * version is defined in Capability.h.
301 struct PartCapability_ {
306 /* No such thing as a MainCapability under THREADED_RTS - each thread must have
307 * its own Capability.
309 #if IN_STG_CODE && !(defined(THREADED_RTS) && !defined(NOSMP))
310 extern W_ MainCapability[];
314 * Assigning to BaseReg (the ASSIGN_BaseReg macro): this happens on
315 * return from a "safe" foreign call, when the thread might be running
316 * on a new Capability. Obviously if BaseReg is not a register, then
317 * we are restricted to a single Capability (this invariant is enforced
318 * in Capability.c:initCapabilities), and assigning to BaseReg can be omitted.
321 #if defined(REG_Base) && !defined(NO_GLOBAL_REG_DECLS)
322 GLOBAL_REG_DECL(StgRegTable *,BaseReg,REG_Base)
323 #define ASSIGN_BaseReg(e) (BaseReg = (e))
325 #if defined(THREADED_RTS) && !defined(NOSMP)
326 #error BaseReg must be in a register for THREADED_RTS
328 #define BaseReg (&((struct PartCapability_ *)MainCapability)->r)
329 #define ASSIGN_BaseReg(e) (e)
332 #if defined(REG_Sp) && !defined(NO_GLOBAL_REG_DECLS)
333 GLOBAL_REG_DECL(P_,Sp,REG_Sp)
335 #define Sp (BaseReg->rSp)
338 #if defined(REG_SpLim) && !defined(NO_GLOBAL_REG_DECLS)
339 GLOBAL_REG_DECL(P_,SpLim,REG_SpLim)
341 #define SpLim (BaseReg->rSpLim)
344 #if defined(REG_Hp) && !defined(NO_GLOBAL_REG_DECLS)
345 GLOBAL_REG_DECL(P_,Hp,REG_Hp)
347 #define Hp (BaseReg->rHp)
350 #if defined(REG_HpLim) && !defined(NO_GLOBAL_REG_DECLS)
351 #error HpLim cannot be in a register
353 #define HpLim (BaseReg->rHpLim)
356 #if defined(REG_CurrentTSO) && !defined(NO_GLOBAL_REG_DECLS)
357 GLOBAL_REG_DECL(struct _StgTSO *,CurrentTSO,REG_CurrentTSO)
359 #define CurrentTSO (BaseReg->rCurrentTSO)
362 #if defined(REG_CurrentNursery) && !defined(NO_GLOBAL_REG_DECLS)
363 GLOBAL_REG_DECL(bdescr *,CurrentNursery,REG_CurrentNursery)
365 #define CurrentNursery (BaseReg->rCurrentNursery)
368 #if defined(REG_HpAlloc) && !defined(NO_GLOBAL_REG_DECLS)
369 GLOBAL_REG_DECL(bdescr *,HpAlloc,REG_HpAlloc)
371 #define HpAlloc (BaseReg->rHpAlloc)
374 /* -----------------------------------------------------------------------------
375 Get absolute function pointers from the register table, to save
384 as long as the offset is within the range of a signed byte
385 (-128..+127). So we pick some common absolute_addresses and put
386 them in the register table. As a bonus, linking time should also
389 Other possible candidates in order of importance:
392 stg_CAF_BLACKHOLE_info
395 anything else probably isn't worth the effort.
397 -------------------------------------------------------------------------- */
400 #define FunReg ((StgFunTable *)((void *)BaseReg - STG_FIELD_OFFSET(struct PartCapability_, r)))
402 #define stg_EAGER_BLACKHOLE_info (FunReg->stgEagerBlackholeInfo)
403 #define stg_gc_enter_1 (FunReg->stgGCEnter1)
404 #define stg_gc_fun (FunReg->stgGCFun)
406 /* -----------------------------------------------------------------------------
407 For any registers which are denoted "caller-saves" by the C calling
408 convention, we have to emit code to save and restore them across C
410 -------------------------------------------------------------------------- */
412 #ifdef CALLER_SAVES_R1
413 #define CALLER_SAVE_R1 SAVE_R1 = R1;
414 #define CALLER_RESTORE_R1 R1 = SAVE_R1;
416 #define CALLER_SAVE_R1 /* nothing */
417 #define CALLER_RESTORE_R1 /* nothing */
420 #ifdef CALLER_SAVES_R2
421 #define CALLER_SAVE_R2 SAVE_R2 = R2;
422 #define CALLER_RESTORE_R2 R2 = SAVE_R2;
424 #define CALLER_SAVE_R2 /* nothing */
425 #define CALLER_RESTORE_R2 /* nothing */
428 #ifdef CALLER_SAVES_R3
429 #define CALLER_SAVE_R3 SAVE_R3 = R3;
430 #define CALLER_RESTORE_R3 R3 = SAVE_R3;
432 #define CALLER_SAVE_R3 /* nothing */
433 #define CALLER_RESTORE_R3 /* nothing */
436 #ifdef CALLER_SAVES_R4
437 #define CALLER_SAVE_R4 SAVE_R4 = R4;
438 #define CALLER_RESTORE_R4 R4 = SAVE_R4;
440 #define CALLER_SAVE_R4 /* nothing */
441 #define CALLER_RESTORE_R4 /* nothing */
444 #ifdef CALLER_SAVES_R5
445 #define CALLER_SAVE_R5 SAVE_R5 = R5;
446 #define CALLER_RESTORE_R5 R5 = SAVE_R5;
448 #define CALLER_SAVE_R5 /* nothing */
449 #define CALLER_RESTORE_R5 /* nothing */
452 #ifdef CALLER_SAVES_R6
453 #define CALLER_SAVE_R6 SAVE_R6 = R6;
454 #define CALLER_RESTORE_R6 R6 = SAVE_R6;
456 #define CALLER_SAVE_R6 /* nothing */
457 #define CALLER_RESTORE_R6 /* nothing */
460 #ifdef CALLER_SAVES_R7
461 #define CALLER_SAVE_R7 SAVE_R7 = R7;
462 #define CALLER_RESTORE_R7 R7 = SAVE_R7;
464 #define CALLER_SAVE_R7 /* nothing */
465 #define CALLER_RESTORE_R7 /* nothing */
468 #ifdef CALLER_SAVES_R8
469 #define CALLER_SAVE_R8 SAVE_R8 = R8;
470 #define CALLER_RESTORE_R8 R8 = SAVE_R8;
472 #define CALLER_SAVE_R8 /* nothing */
473 #define CALLER_RESTORE_R8 /* nothing */
476 #ifdef CALLER_SAVES_R9
477 #define CALLER_SAVE_R9 SAVE_R9 = R9;
478 #define CALLER_RESTORE_R9 R9 = SAVE_R9;
480 #define CALLER_SAVE_R9 /* nothing */
481 #define CALLER_RESTORE_R9 /* nothing */
484 #ifdef CALLER_SAVES_R10
485 #define CALLER_SAVE_R10 SAVE_R10 = R10;
486 #define CALLER_RESTORE_R10 R10 = SAVE_R10;
488 #define CALLER_SAVE_R10 /* nothing */
489 #define CALLER_RESTORE_R10 /* nothing */
492 #ifdef CALLER_SAVES_F1
493 #define CALLER_SAVE_F1 SAVE_F1 = F1;
494 #define CALLER_RESTORE_F1 F1 = SAVE_F1;
496 #define CALLER_SAVE_F1 /* nothing */
497 #define CALLER_RESTORE_F1 /* nothing */
500 #ifdef CALLER_SAVES_F2
501 #define CALLER_SAVE_F2 SAVE_F2 = F2;
502 #define CALLER_RESTORE_F2 F2 = SAVE_F2;
504 #define CALLER_SAVE_F2 /* nothing */
505 #define CALLER_RESTORE_F2 /* nothing */
508 #ifdef CALLER_SAVES_F3
509 #define CALLER_SAVE_F3 SAVE_F3 = F3;
510 #define CALLER_RESTORE_F3 F3 = SAVE_F3;
512 #define CALLER_SAVE_F3 /* nothing */
513 #define CALLER_RESTORE_F3 /* nothing */
516 #ifdef CALLER_SAVES_F4
517 #define CALLER_SAVE_F4 SAVE_F4 = F4;
518 #define CALLER_RESTORE_F4 F4 = SAVE_F4;
520 #define CALLER_SAVE_F4 /* nothing */
521 #define CALLER_RESTORE_F4 /* nothing */
524 #ifdef CALLER_SAVES_D1
525 #define CALLER_SAVE_D1 SAVE_D1 = D1;
526 #define CALLER_RESTORE_D1 D1 = SAVE_D1;
528 #define CALLER_SAVE_D1 /* nothing */
529 #define CALLER_RESTORE_D1 /* nothing */
532 #ifdef CALLER_SAVES_D2
533 #define CALLER_SAVE_D2 SAVE_D2 = D2;
534 #define CALLER_RESTORE_D2 D2 = SAVE_D2;
536 #define CALLER_SAVE_D2 /* nothing */
537 #define CALLER_RESTORE_D2 /* nothing */
540 #ifdef CALLER_SAVES_L1
541 #define CALLER_SAVE_L1 SAVE_L1 = L1;
542 #define CALLER_RESTORE_L1 L1 = SAVE_L1;
544 #define CALLER_SAVE_L1 /* nothing */
545 #define CALLER_RESTORE_L1 /* nothing */
548 #ifdef CALLER_SAVES_Sp
549 #define CALLER_SAVE_Sp SAVE_Sp = Sp;
550 #define CALLER_RESTORE_Sp Sp = SAVE_Sp;
552 #define CALLER_SAVE_Sp /* nothing */
553 #define CALLER_RESTORE_Sp /* nothing */
556 #ifdef CALLER_SAVES_SpLim
557 #define CALLER_SAVE_SpLim SAVE_SpLim = SpLim;
558 #define CALLER_RESTORE_SpLim SpLim = SAVE_SpLim;
560 #define CALLER_SAVE_SpLim /* nothing */
561 #define CALLER_RESTORE_SpLim /* nothing */
564 #ifdef CALLER_SAVES_Hp
565 #define CALLER_SAVE_Hp SAVE_Hp = Hp;
566 #define CALLER_RESTORE_Hp Hp = SAVE_Hp;
568 #define CALLER_SAVE_Hp /* nothing */
569 #define CALLER_RESTORE_Hp /* nothing */
572 #ifdef CALLER_SAVES_Base
574 #error "Can't have caller-saved BaseReg with THREADED_RTS"
576 #define CALLER_SAVE_Base /* nothing */
577 #define CALLER_RESTORE_Base BaseReg = &MainRegTable;
579 #define CALLER_SAVE_Base /* nothing */
580 #define CALLER_RESTORE_Base /* nothing */
583 #ifdef CALLER_SAVES_CurrentTSO
584 #define CALLER_SAVE_CurrentTSO SAVE_CurrentTSO = CurrentTSO;
585 #define CALLER_RESTORE_CurrentTSO CurrentTSO = SAVE_CurrentTSO;
587 #define CALLER_SAVE_CurrentTSO /* nothing */
588 #define CALLER_RESTORE_CurrentTSO /* nothing */
591 #ifdef CALLER_SAVES_CurrentNursery
592 #define CALLER_SAVE_CurrentNursery SAVE_CurrentNursery = CurrentNursery;
593 #define CALLER_RESTORE_CurrentNursery CurrentNursery = SAVE_CurrentNursery;
595 #define CALLER_SAVE_CurrentNursery /* nothing */
596 #define CALLER_RESTORE_CurrentNursery /* nothing */
599 #ifdef CALLER_SAVES_HpAlloc
600 #define CALLER_SAVE_HpAlloc SAVE_HpAlloc = HpAlloc;
601 #define CALLER_RESTORE_HpAlloc HpAlloc = SAVE_HpAlloc;
603 #define CALLER_SAVE_HpAlloc /* nothing */
604 #define CALLER_RESTORE_HpAlloc /* nothing */
607 #endif /* IN_STG_CODE */
609 /* ----------------------------------------------------------------------------
610 Handy bunches of saves/restores
611 ------------------------------------------------------------------------ */
615 #define CALLER_SAVE_USER \
632 /* Save Base last, since the others may
633 be addressed relative to it */
634 #define CALLER_SAVE_SYSTEM \
638 CALLER_SAVE_CurrentTSO \
639 CALLER_SAVE_CurrentNursery \
642 #define CALLER_RESTORE_USER \
659 /* Restore Base first, since the others may
660 be addressed relative to it */
661 #define CALLER_RESTORE_SYSTEM \
662 CALLER_RESTORE_Base \
664 CALLER_RESTORE_SpLim \
666 CALLER_RESTORE_CurrentTSO \
667 CALLER_RESTORE_CurrentNursery
669 #else /* not IN_STG_CODE */
671 #define CALLER_SAVE_USER /* nothing */
672 #define CALLER_SAVE_SYSTEM /* nothing */
673 #define CALLER_RESTORE_USER /* nothing */
674 #define CALLER_RESTORE_SYSTEM /* nothing */
676 #endif /* IN_STG_CODE */
677 #define CALLER_SAVE_ALL \
681 #define CALLER_RESTORE_ALL \
682 CALLER_RESTORE_SYSTEM \