ref: 77c9b908500a4dd502cd94758c51260ec8dda8eb
dir: /6/ra.c/
#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <inttypes.h>
#include <stdarg.h>
#include <assert.h>
#include <limits.h>
#include <string.h>
#include "util.h"
#include "parse.h"
#include "mi.h"
#include "asm.h"
#define Sizetbits (CHAR_BIT*sizeof(size_t)) /* used in graph reprs */
typedef struct Usemap Usemap;
struct Usemap {
int l[Nreg + 1]; /* location of arg used in instruction's arg list */
int r[Nreg + 1]; /* list of registers used implicitly by instruction */
};
void wlprint(FILE *fd, char *name, Loc **wl, size_t nwl);
static int moverelated(Isel *s, regid n);
static void printedge(FILE *fd, char *msg, size_t a, size_t b);
/* tables of uses/defs by instruction */
Usemap usetab[] = {
#define Def(...)
#define Use(...) {__VA_ARGS__}
#define Insn(i, gasfmt, p9fmt, use, def) use,
#include "insns.def"
#undef Insn
#undef Use
#undef Def
};
Usemap deftab[] = {
#define Use(...)
#define Def(...) {__VA_ARGS__}
#define Insn(i, gasfmt, p9fmt, use, def) def,
#include "insns.def"
#undef Insn
#undef Def
#undef Use
};
/* A map of which registers interfere */
#define Northogonal 32
Reg regmap[Northogonal][Nmode] = {
/* None, ModeB, ModeW, ModeL, ModeQ, ModeF, ModeD */
[0] = {Rnone, Ral, Rax, Reax, Rrax, Rnone, Rnone},
[1] = {Rnone, Rcl, Rcx, Recx, Rrcx, Rnone, Rnone},
[2] = {Rnone, Rdl, Rdx, Redx, Rrdx, Rnone, Rnone},
[3] = {Rnone, Rbl, Rbx, Rebx, Rrbx, Rnone, Rnone},
[4] = {Rnone, Rsil, Rsi, Resi, Rrsi, Rnone, Rnone},
[5] = {Rnone, Rdil, Rdi, Redi, Rrdi, Rnone, Rnone},
[6] = {Rnone, Rr8b, Rr8w, Rr8d, Rr8, Rnone, Rnone},
[7] = {Rnone, Rr9b, Rr9w, Rr9d, Rr9, Rnone, Rnone},
[8] = {Rnone, Rr10b, Rr10w, Rr10d, Rr10, Rnone, Rnone},
[9] = {Rnone, Rr11b, Rr11w, Rr11d, Rr11, Rnone, Rnone},
[10] = {Rnone, Rr12b, Rr12w, Rr12d, Rr12, Rnone, Rnone},
[11] = {Rnone, Rr13b, Rr13w, Rr13d, Rr13, Rnone, Rnone},
[12] = {Rnone, Rr14b, Rr14w, Rr14d, Rr14, Rnone, Rnone},
[13] = {Rnone, Rr15b, Rr15w, Rr15d, Rr15, Rnone, Rnone},
[14] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rnone, Rnone},
[15] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rnone, Rnone},
[16] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm0f, Rxmm0d},
[17] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm1f, Rxmm1d},
[18] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm2f, Rxmm2d},
[19] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm3f, Rxmm3d},
[20] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm4f, Rxmm4d},
[21] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm5f, Rxmm5d},
[22] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm6f, Rxmm6d},
[23] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm7f, Rxmm7d},
[24] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm8f, Rxmm8d},
[25] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm9f, Rxmm9d},
[26] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm10f, Rxmm10d},
[27] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm11f, Rxmm11d},
[28] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm12f, Rxmm12d},
[29] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm13f, Rxmm13d},
[30] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm14f, Rxmm14d},
[31] = {Rnone, Rnone, Rnone, Rnone, Rnone, Rxmm15f, Rxmm15d},
};
/* Which regmap entry a register maps to */
int colourmap[Nreg] = {
/* byte */
[Ral] = 0, [Rax] = 0, [Reax] = 0, [Rrax] = 0,
[Rcl] = 1, [Rcx] = 1, [Recx] = 1, [Rrcx] = 1,
[Rdl] = 2, [Rdx] = 2, [Redx] = 2, [Rrdx] = 2,
[Rbl] = 3, [Rbx] = 3, [Rebx] = 3, [Rrbx] = 3,
[Rsil] = 4, [Rsi] = 4, [Resi] = 4, [Rrsi] = 4,
[Rdil] = 5, [Rdi] = 5, [Redi] = 5, [Rrdi] = 5,
[Rr8b] = 6, [Rr8w] = 6, [Rr8d] = 6, [Rr8] = 6,
[Rr9b] = 7, [Rr9w] = 7, [Rr9d] = 7, [Rr9] = 7,
[Rr10b] = 8, [Rr10w] = 8, [Rr10d] = 8, [Rr10] = 8,
[Rr11b] = 9, [Rr11w] = 9, [Rr11d] = 9, [Rr11] = 9,
[Rr12b] = 10, [Rr12w] = 10, [Rr12d] = 10, [Rr12] = 10,
[Rr13b] = 11, [Rr13w] = 11, [Rr13d] = 11, [Rr13] = 11,
[Rr14b] = 12, [Rr14w] = 12, [Rr14d] = 12, [Rr14] = 12,
[Rr15b] = 13, [Rr15w] = 13, [Rr15d] = 13, [Rr15] = 13,
/* float */
[Rxmm0f] = 16, [Rxmm0d] = 16,
[Rxmm1f] = 17, [Rxmm1d] = 17,
[Rxmm2f] = 18, [Rxmm2d] = 18,
[Rxmm3f] = 19, [Rxmm3d] = 19,
[Rxmm4f] = 20, [Rxmm4d] = 20,
[Rxmm5f] = 21, [Rxmm5d] = 21,
[Rxmm6f] = 22, [Rxmm6d] = 22,
[Rxmm7f] = 23, [Rxmm7d] = 23,
[Rxmm8f] = 24, [Rxmm8d] = 24,
[Rxmm9f] = 25, [Rxmm9d] = 25,
[Rxmm10f] = 26, [Rxmm10d] = 26,
[Rxmm11f] = 27, [Rxmm11d] = 27,
[Rxmm12f] = 28, [Rxmm12d] = 28,
[Rxmm13f] = 29, [Rxmm13d] = 29,
[Rxmm14f] = 30, [Rxmm14d] = 30,
[Rxmm15f] = 31, [Rxmm15d] = 31,
};
size_t modesize[Nmode] = {
[ModeNone] = 0,
[ModeB] = 1,
[ModeW] = 2,
[ModeL] = 4,
[ModeQ] = 8,
[ModeF] = 4,
[ModeD] = 8,
};
static int _K[Nclass] = {
[Classbad] = 0,
[Classint] = 14,
[Classflt] = 16,
};
Rclass
rclass(Loc *l)
{
switch (l->mode) {
case ModeNone: return Classbad;
case Nmode: return Classbad;
case ModeB: return Classint;
case ModeW: return Classint;
case ModeL: return Classint;
case ModeQ: return Classint;
case ModeF: return Classflt;
case ModeD: return Classflt;
}
return Classbad;
}
/* %esp, %ebp are not in the allocatable pool */
static int
isfixreg(Loc *l)
{
if (l->reg.colour == Resp)
return 1;
if (l->reg.colour == Rebp)
return 1;
return 0;
}
static size_t
uses(Insn *insn, regid *u)
{
size_t i, j;
int k;
Loc *m;
j = 0;
/* Add all the registers used and defined. Duplicate
* in this list are fine, since they're being added to
* a set anyways */
for (i = 0; i < Maxarg; i++) {
if (!usetab[insn->op].l[i])
break;
k = usetab[insn->op].l[i] - 1;
/* non-registers are handled later */
if (insn->args[k]->type == Locreg)
if (!isfixreg(insn->args[k]))
u[j++] = insn->args[k]->reg.id;
}
/* some insns don't reflect their defs in the args.
* These are explictly listed in the insn description */
for (i = 0; i < Nreg; i++) {
if (!usetab[insn->op].r[i])
break;
/* not a leak; physical registers get memoized */
u[j++] = locphysreg(usetab[insn->op].r[i])->reg.id;
}
/* If the registers are in an address calculation,
* they're used no matter what. */
for (i = 0; i < insn->nargs; i++) {
m = insn->args[i];
if (m->type != Locmem && m->type != Locmeml)
continue;
if (m->mem.base)
if (!isfixreg(m->mem.base))
u[j++] = m->mem.base->reg.id;
if (m->mem.idx)
if (!isfixreg(m->mem.base))
u[j++] = m->mem.idx->reg.id;
}
return j;
}
static size_t
defs(Insn *insn, regid *d)
{
size_t i, j;
int k;
j = 0;
/* Add all the registers dsed and defined. Duplicate
* in this list are fine, since they're being added to
* a set anyways */
for (i = 0; i < Maxarg; i++) {
if (!deftab[insn->op].l[i])
break;
k = deftab[insn->op].l[i] - 1;
if (insn->args[k]->type == Locreg)
if (!isfixreg(insn->args[k]))
d[j++] = insn->args[k]->reg.id;
}
/* some insns don't reflect their defs in the args.
* These are explictly listed in the insn description */
for (i = 0; i < Nreg; i++) {
if (!deftab[insn->op].r[i])
break;
/* not a leak; physical registers get memoized */
d[j++] = locphysreg(deftab[insn->op].r[i])->reg.id;
}
return j;
}
/* The uses and defs for an entire BB. */
static void
udcalc(Asmbb *bb)
{
regid u[Nreg], d[Nreg];
size_t nu, nd;
size_t i, j;
bb->use = bsclear(bb->use);
bb->def = bsclear(bb->def);
for (i = 0; i < bb->ni; i++) {
nu = uses(bb->il[i], u);
nd = defs(bb->il[i], d);
for (j = 0; j < nu; j++)
if (!bshas(bb->def, u[j]))
bsput(bb->use, u[j]);
for (j = 0; j < nd; j++)
bsput(bb->def, d[j]);
}
}
static int
istrivial(Isel *s, regid r)
{
return s->degree[r] < _K[rclass(locmap[r])];
}
static void
liveness(Isel *s)
{
Bitset *old;
Asmbb **bb;
ssize_t nbb;
ssize_t i;
size_t j;
int changed;
bb = s->bb;
nbb = s->nbb;
for (i = 0; i < nbb; i++) {
if (!bb[i])
continue;
udcalc(s->bb[i]);
bb[i]->livein = bsclear(bb[i]->livein);
bb[i]->liveout = bsclear(bb[i]->liveout);
}
changed = 1;
while (changed) {
changed = 0;
old = NULL;
for (i = nbb - 1; i >= 0; i--) {
if (!bb[i])
continue;
old = bsdup(bb[i]->liveout);
/* liveout[b] = U(s in succ) livein[s] */
for (j = 0; bsiter(bb[i]->succ, &j); j++)
bsunion(bb[i]->liveout, bb[j]->livein);
/* livein[b] = use[b] U (out[b] \ def[b]) */
bb[i]->livein = bsclear(bb[i]->livein);
bsunion(bb[i]->livein, bb[i]->liveout);
bsdiff(bb[i]->livein, bb[i]->def);
bsunion(bb[i]->livein, bb[i]->use);
if (!changed)
changed = !bseq(old, bb[i]->liveout);
bsfree(old);
}
}
}
/* we're only interested in register->register moves */
static int
ismove(Insn *i)
{
if (i->op != Imov && i->op != Imovs)
return 0;
return i->args[0]->type == Locreg && i->args[1]->type == Locreg;
}
static int
gbhasedge(Isel *s, size_t u, size_t v)
{
size_t i;
i = (s->nreg * v) + u;
return (s->gbits[i/Sizetbits] & (1ULL <<(i % Sizetbits))) != 0;
}
static void
gbputedge(Isel *s, size_t u, size_t v)
{
size_t i, j;
i = (s->nreg * u) + v;
j = (s->nreg * v) + u;
s->gbits[i/Sizetbits] |= 1ULL << (i % Sizetbits);
s->gbits[j/Sizetbits] |= 1ULL << (j % Sizetbits);
assert(gbhasedge(s, u, v) && gbhasedge(s, v, u));
}
static int
wlfind(Loc **wl, size_t nwl, regid v, size_t *idx)
{
size_t i;
for (i = 0; i < nwl; i++) {
if (wl[i]->reg.id == v) {
*idx = i;
return 1;
}
}
*idx = -1;
return 0;
}
/*
* If we have an edge between two aliasing registers,
* we should not increment the degree, since that would
* be double counting.
*/
static int
degreechange(Isel *s, regid u, regid v)
{
regid phys, virt, r;
size_t i;
if (bshas(s->prepainted, u)) {
phys = u;
virt = v;
} else if (bshas(s->prepainted, v)) {
phys = v;
virt = u;
} else {
return 1;
}
for (i = 0; i < Nmode; i++) {
r = regmap[colourmap[phys]][i];
if (r != phys && gbhasedge(s, virt, regmap[colourmap[phys]][i])) {
return 0;
}
}
return 1;
}
static void
alputedge(Isel *s, regid u, regid v)
{
if (s->ngadj[u] == s->gadjsz[u]) {
s->gadjsz[u] = s->gadjsz[u]*2 + 1;
s->gadj[u] = xrealloc(s->gadj[u], s->gadjsz[u]*sizeof(regid));
}
s->gadj[u][s->ngadj[u]] = v;
s->ngadj[u]++;
}
static void
wlput(Loc ***wl, size_t *nwl, Loc *l)
{
lappend(wl, nwl, l);
l->list = wl;
}
static void
wldel(Isel *s, Loc ***wl, size_t *nwl, size_t idx)
{
(*wl)[idx]->list = NULL;
ldel(wl, nwl, idx);
}
static void
wlputset(Bitset *bs, regid r)
{
bsput(bs, r);
locmap[r]->list = bs;
}
static void
addedge(Isel *s, regid u, regid v)
{
if (u == v || gbhasedge(s, u, v))
return;
if (u == Rrbp || u == Rrsp || u == Rrip)
return;
if (v == Rrbp || v == Rrsp || v == Rrip)
return;
if (rclass(locmap[u]) != rclass(locmap[v]))
return;
if (bshas(s->prepainted, u) && bshas(s->prepainted, v))
return;
gbputedge(s, u, v);
gbputedge(s, v, u);
if (!bshas(s->prepainted, u)) {
alputedge(s, u, v);
s->degree[u] += degreechange(s, v, u);
}
if (!bshas(s->prepainted, v)) {
alputedge(s, v, u);
s->degree[v] += degreechange(s, u, v);
}
}
static void
gfree(Isel *s)
{
size_t i;
for (i = 0; i < s->nreg; i++)
free(s->gadj[i]);
free(s->gbits);
free(s->gadj);
free(s->ngadj);
}
static void
setup(Isel *s)
{
size_t gchunks;
size_t i;
gfree(s);
s->nreg = maxregid;
gchunks = (s->nreg*s->nreg)/Sizetbits + 1;
s->gbits = zalloc(gchunks*sizeof(size_t));
/* fresh adj list repr. */
s->gadj = zalloc(s->nreg * sizeof(regid*));
s->ngadj = zalloc(s->nreg * sizeof(size_t));
s->gadjsz = zalloc(s->nreg * sizeof(size_t));
s->mactiveset = bsclear(s->mactiveset);
s->wlmoveset = bsclear(s->wlmoveset);
s->spilled = bsclear(s->spilled);
s->coalesced = bsclear(s->coalesced);
lfree(&s->wlspill, &s->nwlspill);
lfree(&s->wlfreeze, &s->nwlfreeze);
lfree(&s->wlsimp, &s->nwlsimp);
free(s->aliasmap);
free(s->degree);
free(s->rmoves);
free(s->nrmoves);
s->aliasmap = zalloc(s->nreg * sizeof(Loc*));
s->degree = zalloc(s->nreg * sizeof(int));
s->nuses = zalloc(s->nreg * sizeof(int));
s->rmoves = zalloc(s->nreg * sizeof(Insn**));
s->nrmoves = zalloc(s->nreg * sizeof(size_t));
for (i = 0; bsiter(s->prepainted, &i); i++)
s->degree[i] = 1<<16;
}
static void
build(Isel *s)
{
regid u[Nreg], d[Nreg];
size_t nu, nd;
size_t i, k, a;
ssize_t j;
regid *livesparse;
regid *livedense;
size_t nlive;
regid r;
Asmbb **bb;
size_t nbb;
Insn *insn;
size_t l;
/* set up convenience vars */
bb = s->bb;
nbb = s->nbb;
#define PUT(reg) do { \
assert(reg < maxregid); \
if (livesparse[reg] >= nlive || livedense[livesparse[reg]] != reg) {\
livesparse[reg] = nlive; \
livedense[nlive] = reg; \
nlive++; \
} \
} while(0)
#define DEL(reg) do { \
assert(reg < maxregid); \
regid rtmp; \
if (livesparse[reg] < nlive && livedense[livesparse[reg]] == reg) { \
rtmp = livedense[nlive - 1]; \
livedense[livesparse[reg]] = rtmp; \
livesparse[rtmp] = livesparse[reg]; \
nlive--; \
} \
} while(0)
/* sparse sets are used here because we iterate them. A lot. */
livedense = zalloc((maxregid + 1) * sizeof(regid));
livesparse = zalloc((maxregid + 1) * sizeof(regid));
for (i = 0; i < nbb; i++) {
if (!bb[i])
continue;
nlive = 0;
for (k = 0; bsiter(bb[i]->liveout, &k); k++)
PUT(k);
for (j = bb[i]->ni - 1; j >= 0; j--) {
insn = bb[i]->il[j];
nu = uses(insn, u);
nd = defs(insn, d);
/* add these to the initial set */
for (k = 0; k < nu; k++) {
if (!bshas(s->prepainted, u[k])) {
wlputset(s->initial, u[k]);
s->nuses[u[k]]++;
}
}
for (k = 0; k < nd; k++) {
if (!bshas(s->prepainted, d[k]))
wlputset(s->initial, d[k]);
}
/* moves get special treatment, since we don't want spuriou
* edges between the src and dest */
if (ismove(insn)) {
/* live \= uses(i) */
for (k = 0; k < nu; k++) {
/* remove all physical register aliases */
if (bshas(s->prepainted, u[k])) {
for (a = 0; a < Nmode; a++) {
r = regmap[colourmap[u[k]]][a];
DEL(r);
}
} else {
DEL(u[k]);
}
}
for (k = 0; k < nu; k++)
lappend(&s->rmoves[u[k]], &s->nrmoves[u[k]], insn);
for (k = 0; k < nd; k++)
lappend(&s->rmoves[d[k]], &s->nrmoves[d[k]], insn);
lappend(&s->wlmove, &s->nwlmove, insn);
bsput(s->wlmoveset, insn->uid);
}
/* live = live U def(i) */
for (k = 0; k < nd; k++) {
PUT(d[k]);
}
for (k = 0; k < nd; k++) {
for (l = 0; l < nlive; l++) {
addedge(s, d[k], livedense[l]);
}
}
/* live = use(i) U (live \ def(i)) */
for (k = 0; k < nd; k++) {
DEL(d[k]);
}
for (k = 0; k < nu; k++) {
PUT(u[k]);
}
}
}
free(livedense);
free(livesparse);
#undef PUT
#undef DEL
}
static int
adjavail(Isel *s, regid r)
{
if (locmap[r]->list == &s->selstk)
return 0;
if (bshas(s->coalesced, r))
return 0;
return 1;
}
static size_t
nodemoves(Isel *s, regid n, Insn ***pil)
{
size_t i, count;
regid rid;
Insn **il;
count = 0;
il = malloc(s->nrmoves[n] * sizeof(Insn*));
for (i = 0; i < s->nrmoves[n]; i++) {
rid = s->rmoves[n][i]->uid;
if (bshas(s->mactiveset, rid) || bshas(s->wlmoveset, rid))
il[count++] = s->rmoves[n][i];
}
*pil = il;
return count;
}
static int
moverelated(Isel *s, regid n)
{
size_t i;
for (i = 0; i < s->nrmoves[n]; i++) {
if (bshas(s->mactiveset, s->rmoves[n][i]->uid))
return 1;
if (bshas(s->wlmoveset, s->rmoves[n][i]->uid))
return 1;
}
return 0;
}
static void
mkworklist(Isel *s)
{
size_t i;
for (i = 0; bsiter(s->initial, &i); i++) {
if (bshas(s->prepainted, i))
continue;
else if (!istrivial(s, i))
wlput(&s->wlspill, &s->nwlspill, locmap[i]);
else if (moverelated(s, i)) {
wlput(&s->wlfreeze, &s->nwlfreeze, locmap[i]);
}
else
wlput(&s->wlsimp, &s->nwlsimp, locmap[i]);
locmap[i]->reg.colour = 0;
}
}
static void
enablemove(Isel *s, regid n)
{
size_t i, j;
Insn **il;
size_t ni;
ni = nodemoves(s, n, &il);
for (i = 0; i < ni; i++) {
if (!bshas(s->mactiveset, il[i]->uid))
continue;
for (j = 0; j < s->nmactive; j++) {
if (il[i] == s->mactive[j]) {
ldel(&s->mactive, &s->nmactive, j);
lappend(&s->wlmove, &s->nwlmove, il[i]);
bsdel(s->mactiveset, il[i]->uid);
bsput(s->wlmoveset, il[i]->uid);
}
}
}
free(il);
}
static void
decdegree(Isel *s, regid m)
{
int before, after;
int found;
size_t idx, i;
regid n;
assert(m < s->nreg);
before = istrivial(s, m);
s->degree[m]--;
after = istrivial(s, m);
if (before != after) {
enablemove(s, m);
for (i = 0; i < s->ngadj[m]; i++) {
n = s->gadj[m][i];
if (adjavail(s, n))
enablemove(s, n);
}
/* Subtle:
*
* If this code is being called from coalesce(),
* then the degree could have been bumped up only
* temporarily. This means that the node can already
* be on wlfreeze or wlsimp.
*
* Therefore, if we don't find it on wlspill, we assert
* that the node is already on the list that we'd be
* moving it to.
*/
found = wlfind(s->wlspill, s->nwlspill, m, &idx);
if (found)
wldel(s, &s->wlspill, &s->nwlspill, idx);
if (moverelated(s, m)) {
if (!found) {
assert(wlfind(s->wlfreeze, s->nwlfreeze, m, &idx) != 0);
} else {
wlput(&s->wlfreeze, &s->nwlfreeze, locmap[m]);
}
} else {
if (!found) {
assert(wlfind(s->wlsimp, s->nwlsimp, m, &idx));
} else {
wlput(&s->wlsimp, &s->nwlsimp, locmap[m]);
}
}
}
}
static void
simp(Isel *s)
{
Loc *l;
regid m;
size_t i;
l = lpop(&s->wlsimp, &s->nwlsimp);
wlput(&s->selstk, &s->nselstk, l);
for (i = 0; i < s->ngadj[l->reg.id]; i++) {
m = s->gadj[l->reg.id][i];
if (adjavail(s, m))
decdegree(s, m);
}
}
static regid
getmappedalias(Loc **aliasmap, size_t nreg, regid id)
{
/*
* if we get called from rewrite(), we can get a register that
* we just created, with an id bigger than the number of entrie
* in the alias map. We should just return its id in that case.
*/
while (id < nreg) {
if (!aliasmap[id])
break;
id = aliasmap[id]->reg.id;
};
return id;
}
static regid
getalias(Isel *s, regid id)
{
return getmappedalias(s->aliasmap, s->nreg, id);
}
static void
wladd(Isel *s, regid u)
{
size_t i;
if (bshas(s->prepainted, u))
return;
if (moverelated(s, u))
return;
if (!istrivial(s, u))
return;
assert(locmap[u]->list == &s->wlfreeze || locmap[u]->list == &s->wlsimp);
if (wlfind(s->wlfreeze, s->nwlfreeze, u, &i))
wldel(s, &s->wlfreeze, &s->nwlfreeze, i);
wlput(&s->wlsimp, &s->nwlsimp, locmap[u]);
}
static int
conservative(Isel *s, regid u, regid v)
{
int k;
size_t i;
regid n;
k = 0;
for (i = 0; i < s->ngadj[u]; i++) {
n = s->gadj[u][i];
if (adjavail(s, n) && !istrivial(s, n))
k++;
}
for (i = 0; i < s->ngadj[v]; i++) {
n = s->gadj[v][i];
if (adjavail(s, n) && !istrivial(s, n))
k++;
}
return k < _K[rclass(locmap[u])];
}
/* FIXME: is this actually correct? */
static int
ok(Isel *s, regid t, regid r)
{
return istrivial(s, t) || bshas(s->prepainted, t) || gbhasedge(s, t, r);
}
static int
combinable(Isel *s, regid u, regid v)
{
regid t;
size_t i;
/* Regs of different modes can't be combined as things stand.
* In principle they should be combinable, but it confused the
* whole mode dance. */
if (locmap[u]->mode != locmap[v]->mode)
return 0;
/* if u isn't prepainted, can we conservatively coalesce? */
if (!bshas(s->prepainted, u) && conservative(s, u, v))
return 1;
/* if it is, are the adjacent nodes ok to combine with this? */
for (i = 0; i < s->ngadj[v]; i++) {
t = s->gadj[v][i];
if (adjavail(s, t) && !ok(s, t, u))
return 0;
}
return 1;
}
static void
combine(Isel *s, regid u, regid v)
{
regid t;
size_t idx;
size_t i, j;
int has;
if (debugopt['r'] > 2)
printedge(stdout, "combining:", u, v);
if (wlfind(s->wlfreeze, s->nwlfreeze, v, &idx))
wldel(s, &s->wlfreeze, &s->nwlfreeze, idx);
else if (wlfind(s->wlspill, s->nwlspill, v, &idx)) {
wldel(s, &s->wlspill, &s->nwlspill, idx);
}
wlputset(s->coalesced, v);
s->aliasmap[v] = locmap[u];
s->nuses[u] += s->nuses[v];
/* nodemoves[u] = nodemoves[u] U nodemoves[v] */
for (i = 0; i < s->nrmoves[v]; i++) {
has = 0;
for (j = 0; j < s->nrmoves[u]; j++) {
if (s->rmoves[v][i] == s->rmoves[u][j]) {
has = 1;
break;
}
}
if (!has)
lappend(&s->rmoves[u], &s->nrmoves[u], s->rmoves[v][i]);
}
for (i = 0; i < s->ngadj[v]; i++) {
t = s->gadj[v][i];
if (!adjavail(s, t))
continue;
if (debugopt['r'] > 2)
printedge(stdout, "combine-putedge:", t, u);
addedge(s, t, u);
decdegree(s, t);
}
if (!istrivial(s, u) && wlfind(s->wlfreeze, s->nwlfreeze, u, &idx)) {
wldel(s, &s->wlfreeze, &s->nwlfreeze, idx);
wlput(&s->wlspill, &s->nwlspill, locmap[u]);
}
}
static int
constrained(Isel *s, regid u, regid v)
{
size_t i;
if (bshas(s->prepainted, v))
return 1;
if (bshas(s->prepainted, u))
for (i = 0; i < Nmode; i++)
if (regmap[colourmap[u]][i] && gbhasedge(s, regmap[colourmap[u]][i], v))
return 1;
return gbhasedge(s, u, v);
}
static void
coalesce(Isel *s)
{
Insn *m;
regid u, v, tmp;
m = lpop(&s->wlmove, &s->nwlmove);
bsdel(s->wlmoveset, m->uid);
u = getalias(s, m->args[0]->reg.id);
v = getalias(s, m->args[1]->reg.id);
if (bshas(s->prepainted, v)) {
tmp = u;
u = v;
v = tmp;
}
if (u == v) {
lappend(&s->mcoalesced, &s->nmcoalesced, m);
wladd(s, u);
wladd(s, v);
} else if (constrained(s, u, v)) {
lappend(&s->mconstrained, &s->nmconstrained, m);
wladd(s, u);
wladd(s, v);
} else if (combinable(s, u, v)) {
lappend(&s->mcoalesced, &s->nmcoalesced, m);
combine(s, u, v);
wladd(s, u);
} else {
lappend(&s->mactive, &s->nmactive, m);
bsput(s->mactiveset, m->uid);
}
}
static int
mldel(Insn ***ml, size_t *nml, Bitset *bs, Insn *m)
{
size_t i;
if (bshas(bs, m->uid)) {
bsdel(bs, m->uid);
for (i = 0; i < *nml; i++) {
if (m == (*ml)[i]) {
ldel(ml, nml, i);
return 1;
}
}
}
return 0;
}
static void
freezemoves(Isel *s, Loc *u)
{
size_t i;
Insn **ml;
Insn *m;
size_t nml;
size_t idx;
Loc *v;
nml = nodemoves(s, u->reg.id, &ml);
for (i = 0; i < nml; i++) {
m = ml[i];
if (getalias(s, m->args[0]->reg.id) == getalias(s, u->reg.id))
v = locmap[getalias(s, m->args[1]->reg.id)];
else
v = locmap[getalias(s, m->args[0]->reg.id)];
if (!mldel(&s->mactive, &s->nmactive, s->mactiveset, m))
mldel(&s->wlmove, &s->nwlmove, s->wlmoveset, m);
lappend(&s->mfrozen, &s->nmfrozen, m);
if (!moverelated(s, v->reg.id) && istrivial(s, v->reg.id)) {
if (!wlfind(s->wlfreeze, s->nwlfreeze, v->reg.id, &idx))
die("Reg %zd not in freeze wl\n", v->reg.id);
wldel(s, &s->wlfreeze, &s->nwlfreeze, idx);
wlput(&s->wlsimp, &s->nwlsimp, v);
}
}
lfree(&ml, &nml);
}
static void
freeze(Isel *s)
{
Loc *l;
l = lpop(&s->wlfreeze, &s->nwlfreeze);
wlput(&s->wlsimp, &s->nwlsimp, l);
freezemoves(s, l);
}
/* Select the spill candidates */
static void
selspill(Isel *s)
{
size_t i;
Loc *m;
/* FIXME: pick a better heuristic for spilling */
m = NULL;
for (i = 0; i < s->nwlspill; i++) {
if (!bshas(s->shouldspill, s->wlspill[i]->reg.id))
continue;
m = s->wlspill[i];
wldel(s, &s->wlspill, &s->nwlspill, i);
break;
}
if (!m) {
for (i = 0; i < s->nwlspill; i++) {
if (bshas(s->neverspill, s->wlspill[i]->reg.id)) {
continue;
}
m = s->wlspill[i];
wldel(s, &s->wlspill, &s->nwlspill, i);
break;
}
}
assert(m != NULL);
wlput(&s->wlsimp, &s->nwlsimp, m);
freezemoves(s, m);
}
/*
* Selects the colours for registers, spilling to the
* stack if no free registers can be found.
*/
static int
paint(Isel *s)
{
int taken[Nreg];
Loc *n, *w;
regid l;
size_t i, j;
int spilled;
int found;
spilled = 0;
while (s->nselstk) {
memset(taken, 0, Nreg*sizeof(int));
n = lpop(&s->selstk, &s->nselstk);
for (j = 0; j < s->ngadj[n->reg.id];j++) {
l = s->gadj[n->reg.id][j];
if (debugopt['r'] > 1)
printedge(stdout, "paint-edge:", n->reg.id, l);
w = locmap[getalias(s, l)];
if (w->reg.colour)
taken[colourmap[w->reg.colour]] = 1;
}
found = 0;
for (i = 0; i < Northogonal; i++) {
if (regmap[i][n->mode] && !taken[i]) {
n->reg.colour = regmap[i][n->mode];
found = 1;
break;
}
}
if (!found) {
spilled = 1;
wlputset(s->spilled, n->reg.id);
}
}
for (l = 0; bsiter(s->coalesced, &l); l++) {
n = locmap[getalias(s, l)];
locmap[l]->reg.colour = n->reg.colour;
}
return spilled;
}
static Loc *
mapfind(Isel *s, Htab *map, Loc *old)
{
Loc *new;
Loc *base;
Loc *idx;
regid id;
if (!old)
return NULL;
new = NULL;
if (old->type == Locreg) {
id = getalias(s, old->reg.id);
new = htget(map, locmap[id]);
} else if (old->type == Locmem || old->type == Locmeml) {
base = old->mem.base;
idx = old->mem.idx;
if (base)
base = locmap[getalias(s, base->reg.id)];
if (idx)
idx = locmap[getalias(s, idx->reg.id)];
base = mapfind(s, map, base);
idx = mapfind(s, map, idx);
if (base != old->mem.base || idx != old->mem.idx) {
if (old->type == Locmem)
new = locmems(old->mem.constdisp, base, idx, old->mem.scale, old->mode);
else
new = locmemls(old->mem.lbldisp, base, idx, old->mem.scale, old->mode);
}
}
if (new)
return new;
return old;
}
static Loc *
spillslot(Isel *s, regid reg)
{
size_t stkoff;
stkoff = ptoi(htget(s->spillslots, itop(reg)));
return locmem(-stkoff, locphysreg(Rrbp), NULL, locmap[reg]->mode);
}
static void
updatelocs(Isel *s, Htab *map, Insn *insn)
{
size_t i;
for (i = 0; i < insn->nargs; i++) {
insn->args[i] = mapfind(s, map, insn->args[i]);
insn->args[i] = mapfind(s, map, insn->args[i]);
}
}
/*
* Takes two tables for remappings, of size Nreg/Nreg,
* and fills them, storign the number of uses or defs. Return
* whether there are any remappings at all.
*/
static int
remap(Isel *s, Htab *map, Insn *insn, regid *use, size_t nuse, regid *def, size_t ndef)
{
regid ruse, rdef;
int remapped;
Loc *tmp;
size_t i;
remapped = 0;
for (i = 0; i < nuse; i++) {
ruse = getalias(s, use[i]);
if (!bshas(s->spilled, ruse))
continue;
tmp = locreg(locmap[ruse]->mode);
htput(map, locmap[ruse], tmp);
bsput(s->neverspill, tmp->reg.id);
remapped = 1;
}
for (i = 0; i < ndef; i++) {
rdef = getalias(s, def[i]);
if (!bshas(s->spilled, rdef))
continue;
if (hthas(map, locmap[rdef]))
continue;
tmp = locreg(locmap[rdef]->mode);
htput(map, locmap[rdef], tmp);
bsput(s->neverspill, tmp->reg.id);
remapped = 1;
}
return remapped;
}
static int
nopmov(Isel *s, Insn *insn)
{
if (insn->op != Imov)
return 0;
if (insn->args[0]->type != Locreg || insn->args[1]->type != Locreg)
return 0;
/* Prepainted register moves need to be kept live to avoid coalescing over them */
return insn->args[0]->reg.id == insn->args[1]->reg.id && !bshas(s->prepainted, insn->args[0]->reg.id);
}
void
replacealias(Isel *s, Loc **map, size_t nreg, Insn *insn)
{
size_t i;
Loc *l;
if (!map)
return;
for (i = 0; i < insn->nargs; i++) {
l = insn->args[i];
if (l->type == Locreg) {
insn->args[i] = locmap[getalias(s, l->reg.id)];
} else if (l->type == Locmem || l->type == Locmeml) {
if (l->mem.base)
l->mem.base = locmap[getalias(s, l->mem.base->reg.id)];
if (l->mem.idx)
l->mem.idx = locmap[getalias(s, l->mem.idx->reg.id)];
}
}
}
static ulong
reglochash(void *p)
{
Loc *l;
l = p;
return inthash(l->reg.id);
}
static int
regloceq(void *pa, void *pb)
{
Loc *a, *b;
a = pa;
b = pb;
return a->reg.id == b->reg.id;
}
/*
* Rewrite instructions using spilled registers, inserting
* appropriate loads and stores into the BB
*/
static void
rewritebb(Isel *s, Asmbb *bb, Loc **aliasmap)
{
regid use[Nreg], def[Nreg];
size_t nuse, ndef;
Insn *insn, *mov;
size_t i, j;
Insn **new;
size_t nnew;
Htab *map;
Loc *tmp;
new = NULL;
nnew = 0;
if (!bb)
return;
map = mkht(reglochash, regloceq);
for (j = bb->ni; j > 0; j--) {
insn = bb->il[j - 1];
replacealias(s, aliasmap, s->nreg, insn);
if (nopmov(s, insn))
continue;
nuse = uses(insn, use);
ndef = defs(insn, def);
/* if there is a remapping, insert the loads and stores as needed */
if (remap(s, map, insn, use, nuse, def, ndef)) {
for (i = 0; i < ndef; i++) {
tmp = htget(map, locmap[def[i]]);
if (!tmp)
continue;
if (isfloatmode(tmp->mode))
mov = mkinsn(Imovs, tmp, spillslot(s, def[i]), NULL);
else
mov = mkinsn(Imov, tmp, spillslot(s, def[i]), NULL);
lappend(&new, &nnew, mov);
}
updatelocs(s, map, insn);
lappend(&new, &nnew, insn);
for (i = 0; i < nuse; i++) {
tmp = htget(map, locmap[use[i]]);
if (!tmp)
continue;
if (isfloatmode(tmp->mode))
mov = mkinsn(Imovs, spillslot(s, use[i]), tmp, NULL);
else
mov = mkinsn(Imov, spillslot(s, use[i]), tmp, NULL);
lappend(&new, &nnew, mov);
}
for (i = 0; i < nuse; i++)
htdel(map, locmap[use[i]]);
for (i = 0; i < ndef; i++)
htdel(map, locmap[def[i]]);
} else {
lappend(&new, &nnew, insn);
}
}
for (i = 0; i < nnew/2; i++) {
insn = new[i];
new[i] = new[nnew - i - 1];
new[nnew - i -1] = insn;
}
lfree(&bb->il, &bb->ni);
bb->il = new;
bb->ni = nnew;
}
static void
addspill(Isel *s, Loc *l)
{
s->stksz->lit += modesize[l->mode];
s->stksz->lit = align(s->stksz->lit, modesize[l->mode]);
if (debugopt['r']) {
printf("spill ");
dbglocprint(stdout, l, 'x');
printf(" to %zd(%%rbp)\n", s->stksz->lit);
}
htput(s->spillslots, itop(l->reg.id), itop(s->stksz->lit));
}
/*
* Rewrites the function code so that it no longer contain
* references to spilled registers. Every use of spilled reg
*
* insn %rX,%rY
*
* is rewritten to look like:
*
* mov 123(%rsp),%rZ
* insn %rZ,%rW
* mov %rW,234(%rsp)
*/
static void
rewrite(Isel *s, Loc **aliasmap)
{
size_t i;
s->spillslots = mkht(ptrhash, ptreq);
/* set up stack locations for all spilled registers. */
for (i = 0; bsiter(s->spilled, &i); i++)
addspill(s, locmap[i]);
/* rewrite instructions using them */
for (i = 0; i < s->nbb; i++)
rewritebb(s, s->bb[i], aliasmap);
htfree(s->spillslots);
bsclear(s->spilled);
}
/*
* Coalescing registers leaves a lot
* of moves that look like
*
* mov %r123,%r123.
*
* This is useless. This deletes them.
*/
static void
delnops(Isel *s)
{
Insn *insn;
Asmbb *bb;
Insn **new;
size_t nnew;
size_t i, j;
for (i = 0; i < s->nbb; i++) {
if (!s->bb[i])
continue;
new = NULL;
nnew = 0;
bb = s->bb[i];
for (j = 0; j < bb->ni; j++) {
insn = bb->il[j];
if (ismove(insn) && insn->args[0]->reg.colour == insn->args[1]->reg.colour)
continue;
lappend(&new, &nnew, insn);
}
lfree(&bb->il, &bb->ni);
bb->il = new;
bb->ni = nnew;
}
if (debugopt['r'])
dumpasm(s, stdout);
}
void
regalloc(Isel *s)
{
int spilled;
size_t i;
Loc **aliasmap;
/* Initialize the list of prepainted registers */
s->prepainted = mkbs();
bsput(s->prepainted, 0);
for (i = 0; i < Nreg; i++)
bsput(s->prepainted, i);
s->shouldspill = mkbs();
s->neverspill = mkbs();
s->initial = mkbs();
for (i = 0; i < s->nsaved; i++)
bsput(s->shouldspill, s->calleesave[i]->reg.id);
do {
aliasmap = NULL;
setup(s);
liveness(s);
build(s);
mkworklist(s);
if (debugopt['r'])
dumpasm(s, stdout);
do {
if (s->nwlsimp)
simp(s);
else if (s->nwlmove)
coalesce(s);
else if (s->nwlfreeze)
freeze(s);
else if (s->nwlspill) {
if (!aliasmap)
aliasmap = memdup(s->aliasmap, s->nreg * sizeof(Loc*));
selspill(s);
}
} while (s->nwlsimp || s->nwlmove || s->nwlfreeze || s->nwlspill);
spilled = paint(s);
if (spilled)
rewrite(s, aliasmap);
} while (spilled);
delnops(s);
bsfree(s->prepainted);
bsfree(s->shouldspill);
bsfree(s->neverspill);
gfree(s);
}
void
wlprint(FILE *fd, char *name, Loc **wl, size_t nwl)
{
size_t i;
char *sep;
sep = "";
fprintf(fd, "%s = [", name);
for (i = 0; i < nwl; i++) {
fprintf(fd, "%s", sep);
dbglocprint(fd, wl[i], 'x');
fprintf(fd, "(%zd)", wl[i]->reg.id);
sep = ",";
}
fprintf(fd, "]\n");
}
static void
setprint(FILE *fd, Bitset *s)
{
char *sep;
size_t i;
sep = "";
for (i = 0; i < bsmax(s); i++) {
if (bshas(s, i)) {
fprintf(fd, "%s%zd", sep, i);
sep = ",";
}
}
fprintf(fd, "\n");
}
static void
locsetprint(FILE *fd, Bitset *s)
{
char *sep;
size_t i;
sep = "";
for (i = 0; i < bsmax(s); i++) {
if (bshas(s, i)) {
fprintf(fd, "%s", sep);
dbglocprint(fd, locmap[i], 'x');
sep = ",";
}
}
fprintf(fd, "\n");
}
static void
printedge(FILE *fd, char *msg, size_t a, size_t b)
{
fprintf(fd, "\t%s ", msg);
dbglocprint(fd, locmap[a], 'x');
fprintf(fd, " -- ");
dbglocprint(fd, locmap[b], 'x');
fprintf(fd, "\n");
}
void
dumpasm(Isel *s, FILE *fd)
{
size_t i, j;
char *sep;
Asmbb *bb;
fprintf(fd, "function %s\n", s->name);
fprintf(fd, "WORKLISTS -- \n");
wlprint(stdout, "spill", s->wlspill, s->nwlspill);
wlprint(stdout, "simp", s->wlsimp, s->nwlsimp);
wlprint(stdout, "freeze", s->wlfreeze, s->nwlfreeze);
/* noisy to dump this all the time; only dump for higher debug levels */
if (debugopt['r'] > 2) {
fprintf(fd, "IGRAPH ----- \n");
for (i = 0; i < s->nreg; i++) {
for (j = i; j < s->nreg; j++) {
if (gbhasedge(s, i, j))
printedge(stdout, "", i, j);
}
}
}
fprintf(fd, "ASM -------- \n");
for (j = 0; j < s->nbb; j++) {
bb = s->bb[j];
if (!bb)
continue;
fprintf(fd, "\n");
fprintf(fd, "Bb: %d labels=(", bb->id);
sep = "";
for (i = 0; i < bb->nlbls; i++) {;
fprintf(fd, "%s%s", bb->lbls[i], sep);
sep = ",";
}
fprintf(fd, ")\n");
fprintf(fd, "Pred: ");
setprint(fd, bb->pred);
fprintf(fd, "Succ: ");
setprint(fd, bb->succ);
fprintf(fd, "Use: ");
locsetprint(fd, bb->use);
fprintf(fd, "Def: ");
locsetprint(fd, bb->def);
fprintf(fd, "Livein: ");
locsetprint(fd, bb->livein);
fprintf(fd, "Liveout: ");
locsetprint(fd, bb->liveout);
for (i = 0; i < bb->ni; i++)
dbgiprintf(fd, bb->il[i]);
}
fprintf(fd, "ENDASM -------- \n");
}