1 /* neatcc intermediate code generation */
7 static struct ic
*ic
; /* intermediate code */
8 static long ic_n
, ic_sz
; /* number of instructions in ic[] */
9 static long iv
[NTMPS
]; /* operand stack */
10 static long iv_n
; /* number of values in iv[] */
11 static long *lab_loc
; /* label locations */
12 static long lab_n
, lab_sz
; /* number of labels in lab_loc[] */
13 static long lab_last
; /* the last label target */
15 static int io_num(void);
16 static int io_mul2(void);
17 static int io_cmp(void);
18 static int io_jmp(void);
19 static int io_addr(void);
20 static int io_loc(void);
21 static int io_imm(void);
22 static int io_call(void);
23 static void io_deadcode(void);
25 static void iv_put(long n
);
27 static struct ic
*ic_put(long op
, long arg1
, long arg2
, long arg3
)
31 ic_sz
= MAX(128, ic_sz
* 2);
32 ic
= mextend(ic
, ic_n
, ic_sz
, sizeof(*ic
));
44 static void ic_back(long pos
)
47 for (i
= pos
; i
< ic_n
; i
++)
48 if (ic
[i
].op
& O_CALL
)
53 static long iv_pop(void)
58 static long iv_get(int n
)
60 return iv
[iv_n
- n
- 1];
63 static void iv_put(long n
)
68 static void iv_drop(int n
)
70 iv_n
= MAX(0, iv_n
- n
);
73 static void iv_swap(int x
, int y
)
75 long v
= iv
[iv_n
- x
- 1];
76 iv
[iv_n
- x
- 1] = iv
[iv_n
- y
- 1];
80 static void iv_dup(void)
82 iv
[iv_n
] = iv
[iv_n
- 1];
88 ic_put(O_MOV
| O_NUM
, n
, 0, 0);
93 ic_put(O_MOV
| O_LOC
, id
, 0, 0);
98 ic_put(O_MOV
| O_SYM
, out_sym(sym
), 0, 0);
101 void o_tmpdrop(int n
)
103 iv_drop(n
>= 0 ? n
: iv_n
);
116 /* return one if the given value is constant */
117 static int ic_const(long iv
)
119 long oc
= O_C(ic
[iv
].op
);
120 return oc
& O_MOV
&& oc
& (O_NUM
| O_SYM
| O_LOC
);
123 /* return one if the given value is a simple load */
124 static int ic_load(long iv
)
126 long oc
= O_C(ic
[iv
].op
);
128 if (oc
& O_LD
&& oc
& (O_NUM
| O_SYM
| O_LOC
)) {
129 for (i
= iv
+ 1; i
< ic_n
; i
++)
141 /* load constants as late as possible */
142 if (opt(1) && ic_const(r2
) && !ic_const(r1
)) {
143 ic_put(ic
[r2
].op
, ic
[r2
].a1
, ic
[r2
].a2
, ic
[r2
].a3
);
146 ic_put(op
, r2
, r1
, 0);
158 ic_put(op
, r1
, 0, 0);
165 void o_assign(long bt
)
169 /* load constants as late as possible */
170 if (opt(1) && (ic_const(lv
) || ic_load(lv
))) {
171 ic_put(ic
[lv
].op
, ic
[lv
].a1
, ic
[lv
].a2
, ic
[lv
].a3
);
174 ic_put(O_MK(O_ST
| O_NUM
, bt
), rv
, lv
, 0);
180 void o_deref(long bt
)
183 ic_put(O_MK(O_LD
| O_NUM
, bt
), r1
, 0, 0);
190 if (T_SZ(bt
) != ULNG
) {
192 ic_put(O_MK(O_MOV
, bt
), r1
, 0, 0);
203 ic_put(O_MCPY
, r0
, r1
, r2
);
211 ic_put(O_MSET
, r0
, r1
, r2
);
214 void o_call(int argc
, int ret
)
217 long *args
= malloc(argc
* sizeof(c
->args
[0]));
219 for (i
= argc
- 1; i
>= 0; --i
)
221 for (i
= argc
- 1; i
>= 0; --i
) {
223 /* load constants as late as possible */
224 if (opt(1) && (ic_const(iv
) || ic_load(iv
))) {
225 ic_put(ic
[iv
].op
, ic
[iv
].a1
, ic
[iv
].a2
, ic
[iv
].a3
);
230 c
= ic_put(O_CALL
, r1
, 0, argc
);
241 ic_put(O_RET
, iv_pop(), 0, 0);
244 void o_label(long id
)
246 while (id
>= lab_sz
) {
247 lab_sz
= MAX(128, lab_sz
* 2);
248 lab_loc
= mextend(lab_loc
, lab_n
, lab_sz
, sizeof(*lab_loc
));
251 lab_loc
[lab_n
++] = -1;
258 ic_put(O_JMP
, 0, 0, id
);
263 ic_put(O_JZ
, iv_pop(), 0, id
);
268 int o_popnum(long *n
)
270 if (ic_num(ic
, iv_get(0), n
))
276 int o_popsym(long *sym
, long *off
)
278 if (ic_sym(ic
, iv_get(0), sym
, off
))
289 void o_back(long mark
)
294 void ic_get(struct ic
**c
, long *n
)
297 if (!ic_n
|| ~ic
[ic_n
- 1].op
& O_RET
|| lab_last
== ic_n
)
299 for (i
= 0; i
< ic_n
; i
++) /* filling branch targets */
300 if (ic
[i
].op
& O_JXX
)
301 ic
[i
].a3
= lab_loc
[ic
[i
].a3
];
302 io_deadcode(); /* removing dead code */
316 void ic_free(struct ic
*ic
)
322 /* intermediate code queries */
324 static long cb(long op
, long a
, long b
)
346 return O_T(op
) & T_MSIGN
? a
>> b
: (unsigned long) a
>> b
;
363 static long cu(int op
, long i
)
376 static long c_cast(long n
, unsigned bt
)
378 if (!(bt
& T_MSIGN
) && T_SZ(bt
) != ULNG
)
379 n
&= ((1l << (long) (T_SZ(bt
) * 8)) - 1);
380 if (bt
& T_MSIGN
&& T_SZ(bt
) != ULNG
&&
381 n
> (1l << (T_SZ(bt
) * 8 - 1)))
382 n
= -((1l << (T_SZ(bt
) * 8)) - n
);
386 int ic_num(struct ic
*ic
, long iv
, long *n
)
389 long oc
= O_C(ic
[iv
].op
);
390 long bt
= O_T(ic
[iv
].op
);
391 if (oc
& O_MOV
&& oc
& O_NUM
) {
396 if (ic_num(ic
, ic
[iv
].a1
, &n1
))
398 if (ic_num(ic
, ic
[iv
].a2
, &n2
))
400 *n
= cb(ic
[iv
].op
, n1
, n2
);
404 if (ic_num(ic
, ic
[iv
].a1
, &n1
))
406 *n
= cu(ic
[iv
].op
, n1
);
409 if (oc
& O_MOV
&& !(oc
& (O_NUM
| O_LOC
| O_SYM
))) {
410 if (ic_num(ic
, ic
[iv
].a1
, &n1
))
418 int ic_sym(struct ic
*ic
, long iv
, long *sym
, long *off
)
421 long oc
= O_C(ic
[iv
].op
);
422 if (oc
& O_MOV
&& oc
& O_SYM
) {
428 if ((ic_sym(ic
, ic
[iv
].a1
, sym
, off
) ||
429 ic_num(ic
, ic
[iv
].a2
, &n
)) &&
430 (ic_sym(ic
, ic
[iv
].a2
, sym
, off
) ||
431 ic_num(ic
, ic
[iv
].a1
, &n
)))
437 if (ic_sym(ic
, ic
[iv
].a1
, sym
, off
) ||
438 ic_num(ic
, ic
[iv
].a2
, &n
))
446 static int ic_off(struct ic
*ic
, long iv
, long *base_iv
, long *off
)
449 long oc
= O_C(ic
[iv
].op
);
450 if (oc
== (O_ADD
| O_NUM
)) {
451 *base_iv
= ic
[iv
].a1
;
455 if (oc
== (O_SUB
| O_NUM
)) {
456 *base_iv
= ic
[iv
].a1
;
461 if ((ic_off(ic
, ic
[iv
].a1
, base_iv
, off
) ||
462 ic_num(ic
, ic
[iv
].a2
, &n
)) &&
463 (ic_off(ic
, ic
[iv
].a2
, base_iv
, off
) ||
464 ic_num(ic
, ic
[iv
].a1
, &n
)))
470 if (ic_off(ic
, ic
[iv
].a1
, base_iv
, off
) ||
471 ic_num(ic
, ic
[iv
].a2
, &n
))
481 /* number of register arguments */
482 int ic_regcnt(struct ic
*ic
)
486 return o
& (O_NUM
| O_SYM
| O_LOC
) ? 1 : 2;
488 return o
& (O_NUM
| O_SYM
| O_LOC
) ? 0 : 1;
490 return o
& (O_NUM
| O_SYM
| O_LOC
) ? 0 : 1;
492 return o
& (O_NUM
| O_SYM
| O_LOC
) ? 0 : 1;
500 return o
& (O_NUM
| O_SYM
| O_LOC
) ? 1 : 2;
504 return ((o
& O_NUM
) != 0);
506 return 1 + ((o
& O_NUM
) != 0);
511 * The returned array indicates the last instruction in
512 * which the value produced by each instruction is used.
514 long *ic_lastuse(struct ic
*ic
, long ic_n
)
516 long *luse
= calloc(ic_n
, sizeof(luse
[0]));
518 for (i
= ic_n
- 1; i
>= 0; --i
) {
519 int n
= ic_regcnt(ic
+ i
);
521 if (!(ic
[i
].op
& O_OUT
) || ic
[i
].op
& O_CALL
)
525 if (n
>= 1 && !luse
[ic
[i
].a1
])
527 if (n
>= 2 && !luse
[ic
[i
].a2
])
529 if (n
>= 3 && !luse
[ic
[i
].a3
])
531 if (ic
[i
].op
& O_CALL
)
532 for (j
= 0; j
< ic
[i
].a3
; j
++)
533 if (!luse
[ic
[i
].args
[j
]])
534 luse
[ic
[i
].args
[j
]] = i
;
539 /* intermediate code optimisations */
541 /* constant folding */
542 static int io_num(void)
545 if (!ic_num(ic
, iv_get(0), &n
)) {
553 static int log2a(unsigned long n
)
556 for (i
= 0; i
< LONGSZ
* 8; i
++)
559 if (i
== LONGSZ
* 8 || !(n
>> (i
+ 1)))
564 static long iv_num(long n
)
570 /* optimised multiplication operations for powers of two */
571 static int io_mul2(void)
576 long oc
= O_C(ic
[iv
].op
);
577 long bt
= O_T(ic
[iv
].op
);
580 if (oc
== O_MUL
&& !ic_num(ic
, ic
[iv
].a1
, &n
)) {
582 ic
[iv
].a1
= ic
[iv
].a2
;
585 if (ic_num(ic
, ic
[iv
].a2
, &n
))
601 ic_put(O_MK(O_SHL
, ULNG
), ic
[iv
].a1
, r2
, 0);
604 if (oc
== O_DIV
&& ~bt
& T_MSIGN
) {
611 ic_put(O_MK(O_SHR
, ULNG
), ic
[iv
].a1
, r2
, 0);
614 if (oc
== O_MOD
&& ~bt
& T_MSIGN
) {
620 r2
= iv_num(LONGSZ
* 8 - p
);
621 ic_put(O_MK(O_SHL
, ULNG
), ic
[iv
].a1
, r2
, 0);
623 r2
= iv_num(LONGSZ
* 8 - p
);
624 ic_put(O_MK(O_SHR
, ULNG
), r1
, r2
, 0);
630 /* optimise comparison */
631 static int io_cmp(void)
634 long cmp
= ic
[iv
].a1
;
635 if (O_C(ic
[iv
].op
) == O_LNOT
&& ic
[cmp
].op
& O_CMP
) {
644 /* optimise branch instructions after comparison */
645 static int io_jmp(void)
647 struct ic
*c
= &ic
[ic_n
- 1];
648 long oc
= O_C(c
->op
);
649 if (oc
& O_JZ
&& O_C(ic
[c
->a1
].op
) == O_LNOT
) {
650 c
->a1
= ic
[c
->a1
].a1
;
654 if (oc
& O_JZ
&& O_C(ic
[c
->a1
].op
) & O_CMP
) {
655 long cop
= (ic
[c
->a1
].op
& ~O_CMP
) | O_JCC
;
656 c
->op
= O_C(c
->op
) == O_JZ
? cop
^ 1 : cop
;
657 c
->a2
= ic
[c
->a1
].a2
;
658 c
->a1
= ic
[c
->a1
].a1
;
664 /* optimise accessing locals or symbols with an offset */
665 static int io_addr(void)
668 if (ic_off(ic
, iv_get(0), &iv
, &off
) || iv
== iv_get(0))
670 if (ic
[iv
].op
& O_MOV
&& ic
[iv
].op
& O_LOC
) {
672 ic_put(O_MOV
| O_LOC
, ic
[iv
].a1
, ic
[iv
].a2
+ off
, 0);
675 if (ic
[iv
].op
& O_MOV
&& ic
[iv
].op
& O_SYM
) {
677 ic_put(O_MOV
| O_SYM
, ic
[iv
].a1
, ic
[iv
].a2
+ off
, 0);
683 static int imm_ok(long op
, long n
, int arg
)
686 if (i_reg(op
| O_NUM
, m
+ 0, m
+ 1, m
+ 2, m
+ 3, m
+ 4))
688 return i_imm(m
[arg
], n
);
691 /* optimise loading and storing locals */
692 static int io_loc(void)
694 struct ic
*c
= &ic
[ic_n
- 1];
696 if (c
->op
& O_LD
&& c
->op
& O_NUM
) {
697 if (ic_off(ic
, c
->a1
, &iv
, &off
))
699 if (ic
[iv
].op
& O_MOV
&& ic
[iv
].op
& O_LOC
) {
700 c
->op
= (c
->op
& ~O_NUM
) | O_LOC
;
702 c
->a2
+= ic
[iv
].a2
+ off
;
705 if (imm_ok(c
->op
, off
, 2)) {
711 if (c
->op
& O_ST
&& c
->op
& O_NUM
) {
712 if (ic_off(ic
, c
->a2
, &iv
, &off
))
714 if (ic
[iv
].op
& O_MOV
&& ic
[iv
].op
& O_LOC
) {
715 c
->op
= (c
->op
& ~O_NUM
) | O_LOC
;
717 c
->a3
+= ic
[iv
].a2
+ off
;
720 if (imm_ok(c
->op
, off
, 3)) {
729 /* use instruction immediates */
730 static int io_imm(void)
732 struct ic
*c
= &ic
[ic_n
- 1];
733 long oc
= O_C(c
->op
);
735 if (oc
& (O_NUM
| O_LOC
| O_SYM
))
737 if (oc
== O_ADD
|| oc
== O_MUL
|| oc
== O_AND
|| oc
== O_OR
||
738 oc
== O_XOR
|| oc
== O_EQ
|| oc
== O_NE
) {
739 if (!ic_num(ic
, c
->a1
, &n
)) {
745 if (oc
== O_LT
|| oc
== O_GE
|| oc
== O_LE
|| oc
== O_GT
) {
746 if (!ic_num(ic
, c
->a1
, &n
)) {
753 if (oc
& O_JCC
&& !ic_num(ic
, c
->a1
, &n
)) {
759 if (oc
& O_JCC
&& !ic_num(ic
, c
->a2
, &n
) && imm_ok(c
->op
, n
, 1)) {
764 if (!(oc
& O_BOP
) || ic_num(ic
, c
->a2
, &n
))
766 if ((oc
== O_ADD
|| oc
== O_SUB
|| oc
& O_SHL
) && n
== 0) {
771 if (imm_ok(c
->op
, n
, 2)) {
779 /* calling symbols */
780 static int io_call(void)
782 struct ic
*c
= &ic
[ic_n
- 1];
784 if (c
->op
& O_CALL
&& !ic_sym(ic
, c
->a1
, &sym
, &off
) && !off
) {
792 /* remove dead code */
793 static void io_deadcode(void)
797 long src
= 0, dst
= 0;
799 /* liveness analysis */
800 live
= calloc(ic_n
, sizeof(live
[0]));
801 for (i
= ic_n
- 1; i
>= 0; i
--) {
802 int n
= ic_regcnt(ic
+ i
);
803 if (!(ic
[i
].op
& O_OUT
) || ic
[i
].op
& O_CALL
)
813 if (ic
[i
].op
& O_CALL
)
814 for (j
= 0; j
< ic
[i
].a3
; j
++)
815 live
[ic
[i
].args
[j
]] = 1;
817 /* the new indices of intermediate instructions */
818 nidx
= calloc(ic_n
, sizeof(nidx
[0]));
820 while (src
< ic_n
&& !live
[src
]) {
827 memcpy(ic
+ dst
, ic
+ src
, sizeof(ic
[src
]));
833 /* adjusting arguments and branch targets */
834 for (i
= 0; i
< ic_n
; i
++) {
835 int n
= ic_regcnt(ic
+ i
);
837 ic
[i
].a1
= nidx
[ic
[i
].a1
];
839 ic
[i
].a2
= nidx
[ic
[i
].a2
];
841 ic
[i
].a3
= nidx
[ic
[i
].a3
];
842 if (ic
[i
].op
& O_JXX
)
843 ic
[i
].a3
= nidx
[ic
[i
].a3
];
844 if (ic
[i
].op
& O_CALL
)
845 for (j
= 0; j
< ic
[i
].a3
; j
++)
846 ic
[i
].args
[j
] = nidx
[ic
[i
].args
[j
]];