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
|
#include "ir.h"
static void
porec(int *nblk, Block ***rpo, Block *b)
{
if (wasvisited(b)) return;
assert(*nblk > 0 && "nblk bad");
--*nblk;
markvisited(b);
if (b->s2) porec(nblk, rpo, b->s2);
if (b->s1) porec(nblk, rpo, b->s1);
*--*rpo = b;
}
/* also blkid */
void
sortrpo(Function *fn)
{
static Block **rpobuf;
Block **rpoend, **rpo, *blk, *next;
int i, ndead;
xbgrow(&rpobuf, fn->nblk);
rpo = rpoend = rpobuf + fn->nblk,
startbbvisit();
fn->entry->id = 0;
int nblk = fn->nblk;
porec(&nblk, &rpo, fn->entry);
ndead = rpo - rpobuf;
if (ndead > 0) for (blk = fn->entry->lprev; blk != fn->entry; blk = next) {
next = blk->lprev;
if (!wasvisited(blk)) {
for (int i = 0; i < blk->ins.n; ++i) {
/* if unreachable block has alloca pseudo-instrs, move them to the entry
* to be able to delete it */
if (oisalloca(instrtab[blk->ins.p[i]].op)) {
vpush(&fn->entry->ins, blk->ins.p[i]);
}
}
for (int i = 0; i < blk->npred; ++i)
assert(!wasvisited(blkpred(blk, i)));
freeblk(fn, blk);
--ndead;
}
}
for (i = 1, ++rpo; rpo < rpoend; ++rpo, ++i) {
rpo[-1]->lnext = rpo[0];
rpo[0]->lprev = rpo[-1];
rpo[0]->id = i;
}
fn->entry->lprev = rpo[-1];
rpo[-1]->lnext = fn->entry;
fn->prop |= FNBLKID | FNRPO;
}
/* also blkid */
void
filldom(Function *fn)
{
Block *blk = fn->entry;
int i = 0;
FREQUIRE(FNRPO);
/* Implements 'A Simple, Fast Dominance Algorithm' by K. Cooper, T. Harvey, and K. Kennedy */
do blk->id = i++, blk->idom = NULL; while ((blk = blk->lnext) != fn->entry);
fn->entry->idom = fn->entry;
for (bool changed = 1; changed;) {
changed = 0;
do {
int j;
Block *new = NULL;
if (blk->npred == 0) continue;
for (j = 0; j < blk->npred; ++j)
if ((new = blkpred(blk, j))->id < blk->id) break;
assert(new);
for (int i = 0; i < blk->npred; ++i) {
if (i == j) continue;
Block *p = blkpred(blk, i);
if (p->idom) { /* new = intersect(p, new) */
while (p != new) {
while (p->id > new->id) p = p->idom;
while (p->id < new->id) new = new->idom;
}
}
}
if (blk->idom != new) {
blk->idom = new;
changed = 1;
}
} while ((blk = blk->lnext) != fn->entry);
}
fn->prop |= FNBLKID | FNDOM;
}
static void
loopmark(Block *head, Block *blk)
{
if (blk->id < head->id || blk->visit == head->id) return;
blk->visit = head->id;
++blk->loop;
for (int i = 0; i < blk->npred; ++i)
loopmark(head, blkpred(blk, i));
}
void
fillloop(Function *fn)
{
Block *b = fn->entry;
int id = 0;
FREQUIRE(FNRPO);
do {
b->id = id++;
b->visit = -1u;
b->loop = 0;
} while ((b = b->lnext) != fn->entry);
do {
for (int i = 0; i < b->npred; ++i) {
Block *p = blkpred(b, i);
if (p->id > b->id) { /* b is loop header */
loopmark(b, p);
}
}
} while ((b = b->lnext) != fn->entry);
fn->prop |= FNBLKID;
}
/* vim:set ts=3 sw=3 expandtab: */
|
