ref: a64576667fa432665cf01edfbb24658135351c54
dir: /6/isel.c/
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <stdarg.h>
#include <inttypes.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "parse.h"
#include "opt.h"
#include "asm.h"
#include "../config.h"
/* string tables */
char *insnfmts[] = {
#define Insn(val, fmt, use, def) fmt,
#include "insns.def"
#undef Insn
};
char* modenames[] = {
[ModeB] = "b",
[ModeW] = "w",
[ModeL] = "l",
[ModeQ] = "q",
[ModeF] = "s",
[ModeD] = "d"
};
/* forward decls */
Loc *selexpr(Isel *s, Node *n);
static size_t writeblob(FILE *fd, Htab *globls, Htab *strtab, Node *blob);
/* used to decide which operator is appropriate
* for implementing various conditional operators */
struct {
AsmOp test;
AsmOp jmp;
AsmOp getflag;
} reloptab[Numops] = {
[Olnot] = {Itest, Ijz, Isetz}, /* lnot invalid for floats */
/* signed int */
[Oeq] = {Icmp, Ijz, Isetz},
[One] = {Icmp, Ijnz, Isetnz},
[Ogt] = {Icmp, Ijg, Isetg},
[Oge] = {Icmp, Ijge, Isetge},
[Olt] = {Icmp, Ijl, Isetl},
[Ole] = {Icmp, Ijle, Isetle},
/* unsigned int */
[Oueq] = {Icmp, Ijz, Isetz},
[Oune] = {Icmp, Ijnz, Isetnz},
[Ougt] = {Icmp, Ija, Iseta},
[Ouge] = {Icmp, Ijae, Isetae},
[Oult] = {Icmp, Ijb, Isetb},
[Oule] = {Icmp, Ijbe, Isetbe},
/* float */
[Ofeq] = {Icomis, Ijz, Isetz},
[Ofne] = {Icomis, Ijnz, Isetnz},
[Ofgt] = {Icomis, Ija, Iseta},
[Ofge] = {Icomis, Ijae, Isetae},
[Oflt] = {Icomis, Ijb, Isetb},
[Ofle] = {Icomis, Ijbe, Isetbe},
};
static Mode mode(Node *n)
{
Type *t;
t = tybase(exprtype(n));
/* FIXME: What should the mode for, say, structs be when we have no
* intention of loading /through/ the pointer? For now, we'll just say it's
* the pointer mode, since we expect to address through the pointer */
switch (t->type) {
case Tyfloat32: return ModeF; break;
case Tyfloat64: return ModeD; break;
default:
if (stacktype(t))
return ModeQ;
switch (size(n)) {
case 1: return ModeB; break;
case 2: return ModeW; break;
case 4: return ModeL; break;
case 8: return ModeQ; break;
}
break;
}
return ModeQ;
}
static int isintmode(Mode m)
{
return m == ModeB || m == ModeW || m == ModeL || m == ModeQ;
}
static int isfloatmode(Mode m)
{
return m == ModeF || m == ModeD;
}
static Loc *loc(Isel *s, Node *n)
{
ssize_t stkoff;
Loc *l, *rip;
Node *v;
switch (exprop(n)) {
case Ovar:
if (hthas(s->globls, n)) {
rip = locphysreg(Rrip);
l = locmeml(htget(s->globls, n), rip, NULL, mode(n));
} else if (hthas(s->stkoff, n)) {
stkoff = ptoi(htget(s->stkoff, n));
l = locmem(-stkoff, locphysreg(Rrbp), NULL, mode(n));
} else {
if (!hthas(s->reglocs, n))
htput(s->reglocs, n, locreg(mode(n)));
return htget(s->reglocs, n);
}
break;
case Olit:
v = n->expr.args[0];
switch (v->lit.littype) {
case Lchr: l = loclit(v->lit.chrval, mode(n)); break;
case Lbool: l = loclit(v->lit.boolval, mode(n)); break;
case Lint: l = loclit(v->lit.intval, mode(n)); break;
default:
die("Literal type %s should be blob", litstr(v->lit.littype));
}
break;
default:
die("Node %s not leaf in loc()", opstr(exprop(n)));
break;
}
return l;
}
static Insn *mkinsnv(AsmOp op, va_list ap)
{
Loc *l;
Insn *i;
int n;
static size_t insnid;
n = 0;
i = malloc(sizeof(Insn));
i->op = op;
i->uid = insnid++;
while ((l = va_arg(ap, Loc*)) != NULL)
i->args[n++] = l;
i->nargs = n;
return i;
}
Insn *mkinsn(AsmOp op, ...)
{
va_list ap;
Insn *i;
va_start(ap, op);
i = mkinsnv(op, ap);
va_end(ap);
return i;
}
void g(Isel *s, AsmOp op, ...)
{
va_list ap;
Insn *i;
va_start(ap, op);
i = mkinsnv(op, ap);
va_end(ap);
if (debugopt['i']) {
printf("GEN ");
iprintf(stdout, i);
}
lappend(&s->curbb->il, &s->curbb->ni, i);
}
static void movz(Isel *s, Loc *src, Loc *dst)
{
if (src->mode == dst->mode)
g(s, Imov, src, dst, NULL);
else
g(s, Imovzx, src, dst, NULL);
}
static void load(Isel *s, Loc *a, Loc *b)
{
Loc *l;
assert(b->type == Locreg);
if (a->type == Locreg)
l = locmem(0, b, Rnone, a->mode);
else
l = a;
if (isfloatmode(b->mode))
g(s, Imovs, l, b, NULL);
else
g(s, Imov, l, b, NULL);
}
static void stor(Isel *s, Loc *a, Loc *b)
{
Loc *l;
assert(a->type == Locreg || a->type == Loclit);
if (b->type == Locreg)
l = locmem(0, b, Rnone, b->mode);
else
l = b;
if (isfloatmode(b->mode))
g(s, Imovs, a, l, NULL);
else
g(s, Imov, a, l, NULL);
}
/* ensures that a location is within a reg */
static Loc *newr(Isel *s, Loc *a)
{
Loc *r;
r = locreg(a->mode);
if (a->type == Locreg) {
if (isfloatmode(a->mode))
g(s, Imovs, a, r, NULL);
else
g(s, Imov, a, r, NULL);
} else {
load(s, a, r);
}
return r;
}
static Loc *inr(Isel *s, Loc *a)
{
if (a->type == Locreg)
return a;
return newr(s, a);
}
/* ensures that a location is within a reg or an imm */
static Loc *inri(Isel *s, Loc *a)
{
if (a->type == Locreg || a->type == Loclit)
return a;
else
return newr(s, a);
}
/* If we're testing equality, etc, it's a bit silly
* to generate the test, store it to a bite, expand it
* to the right width, and then test it again. Try to optimize
* for these common cases.
*
* if we're doing the optimization to avoid
* multiple tests, we want to eval the children
* of the first arg, instead of the first arg
* directly */
static void selcjmp(Isel *s, Node *n, Node **args)
{
Loc *a, *b;
Loc *l1, *l2;
AsmOp cond, jmp;
cond = reloptab[exprop(args[0])].test;
jmp = reloptab[exprop(args[0])].jmp;
/* if we have a cond, we're knocking off the redundant test,
* and want to eval the children */
if (cond) {
a = selexpr(s, args[0]->expr.args[0]);
if (args[0]->expr.nargs == 2)
b = selexpr(s, args[0]->expr.args[1]);
else
b = a;
a = newr(s, a);
} else {
cond = Itest;
jmp = Ijnz;
b = newr(s, selexpr(s, args[0])); /* cond */
a = b;
}
/* the jump targets will always be evaluated the same way */
l1 = loclbl(args[1]); /* if true */
l2 = loclbl(args[2]); /* if false */
g(s, cond, b, a, NULL);
g(s, jmp, l1, NULL);
g(s, Ijmp, l2, NULL);
}
static Loc *binop(Isel *s, AsmOp op, Node *x, Node *y)
{
Loc *a, *b;
a = selexpr(s, x);
b = selexpr(s, y);
a = newr(s, a);
g(s, op, b, a, NULL);
return a;
}
/* We have a few common cases to optimize here:
* Oaddr(expr)
* or:
* Oadd(
* reg,
* reg||const)
*
* or:
* Oadd(
* reg,
* Omul(reg,
* 2 || 4 || 8)))
*/
static int ismergablemul(Node *n, int *r)
{
int v;
if (exprop(n) != Omul)
return 0;
if (exprop(n->expr.args[1]) != Olit)
return 0;
if (n->expr.args[1]->expr.args[0]->type != Nlit)
return 0;
if (n->expr.args[1]->expr.args[0]->lit.littype != Lint)
return 0;
v = n->expr.args[1]->expr.args[0]->lit.intval;
if (v != 2 && v != 4 && v != 8)
return 0;
*r = v;
return 1;
}
static Loc *memloc(Isel *s, Node *e, Mode m)
{
Node **args;
Loc *l, *b, *o; /* location, base, offset */
int scale;
scale = 1;
l = NULL;
args = e->expr.args;
if (exprop(e) == Oadd) {
b = selexpr(s, args[0]);
if (ismergablemul(args[1], &scale))
o = selexpr(s, args[1]->expr.args[0]);
else
o = selexpr(s, args[1]);
if (b->type != Locreg)
b = inr(s, b);
if (o->type == Loclit) {
l = locmem(scale*o->lit, b, Rnone, m);
} else {
b = inr(s, b);
o = inr(s, o);
l = locmems(0, b, o, scale, m);
}
} else {
l = selexpr(s, e);
l = inr(s, l);
l = locmem(0, l, Rnone, m);
}
assert(l != NULL);
return l;
}
static void blit(Isel *s, Loc *to, Loc *from, size_t dstoff, size_t srcoff, size_t sz, size_t align)
{
static const Mode modes[] = {
[8] = ModeQ,
[4] = ModeL,
[2] = ModeW,
[1] = ModeB
};
size_t i, modesz;
Loc *sp, *dp, *len; /* pointers to src, dst */
Loc *tmp, *src, *dst; /* source memory, dst memory */
assert(modes[align] != ModeNone); /* make sure we have a valid alignment */
sp = inr(s, from);
dp = inr(s, to);
i = 0;
if (sz <= 64*align) { /* arbitrary threshold; should be tuned */
for (modesz = align; modes[modesz] != ModeNone; modesz /= 2) {
tmp = locreg(modes[modesz]);
while (i + modesz <= sz) {
src = locmem(i + srcoff, sp, NULL, modes[modesz]);
dst = locmem(i + dstoff, dp, NULL, modes[modesz]);
g(s, Imov, src, tmp, NULL);
g(s, Imov, tmp, dst, NULL);
i += modesz;
}
}
} else {
len = loclit(sz, ModeQ);
sp = newr(s, from);
dp = newr(s, to);
/* length to blit */
g(s, Imov, len, locphysreg(Rrcx), NULL);
/* source address with offset */
if (srcoff)
g(s, Ilea, locmem(srcoff, sp, NULL, ModeQ), locphysreg(Rrsi), NULL);
else
g(s, Imov, sp, locphysreg(Rrsi), NULL);
/* dest address with offset */
if (dstoff)
g(s, Ilea, locmem(dstoff, dp, NULL, ModeQ), locphysreg(Rrdi), NULL);
else
g(s, Imov, dp, locphysreg(Rrdi), NULL);
g(s, Irepmovsb, NULL);
}
}
static int isconstfunc(Isel *s, Node *n)
{
Node *d;
if (exprop(n) != Ovar)
return 0;
if (!hthas(s->globls, n))
return 0;
d = decls[n->expr.did];
if (d && d->decl.isconst)
return tybase(decltype(d))->type == Tyfunc;
return 0;
}
static void call(Isel *s, Node *n)
{
AsmOp op;
Loc *f;
if (isconstfunc(s, n)) {
op = Icall;
f = locmeml(htget(s->globls, n), NULL, NULL, mode(n));
} else {
op = Icallind;
f = selexpr(s, n);
}
g(s, op, f, NULL);
}
static Loc *gencall(Isel *s, Node *n)
{
Loc *src, *dst, *arg; /* values we reduced */
Loc *retloc, *rsp, *ret; /* hard-coded registers */
Loc *stkbump; /* calculated stack offset */
int argsz, argoff;
size_t i, a;
rsp = locphysreg(Rrsp);
if (tybase(exprtype(n))->type == Tyvoid) {
retloc = NULL;
ret = NULL;
} else if (stacktype(exprtype(n))) {
retloc = locphysreg(Rrax);
ret = locreg(ModeQ);
} else if (floattype(exprtype(n))) {
retloc = coreg(Rxmm0d, mode(n));
ret = locreg(mode(n));
} else {
retloc = coreg(Rrax, mode(n));
ret = locreg(mode(n));
}
argsz = 0;
/* Have to calculate the amount to bump the stack
* pointer by in one pass first, otherwise if we push
* one at a time, we evaluate the args in reverse order.
* Not good.
*
* Skip the first operand, since it's the function itself */
for (i = 1; i < n->expr.nargs; i++) {
argsz = align(argsz, min(size(n->expr.args[i]), Ptrsz));
argsz += size(n->expr.args[i]);
}
argsz = align(argsz, 16);
stkbump = loclit(argsz, ModeQ);
if (argsz)
g(s, Isub, stkbump, rsp, NULL);
/* Now, we can evaluate the arguments */
argoff = 0;
for (i = 1; i < n->expr.nargs; i++) {
arg = selexpr(s, n->expr.args[i]);
argoff = align(argoff, min(size(n->expr.args[i]), Ptrsz));
if (stacknode(n->expr.args[i])) {
src = locreg(ModeQ);
g(s, Ilea, arg, src, NULL);
a = alignto(1, n->expr.args[i]->expr.type);
blit(s, rsp, src, argoff, 0, size(n->expr.args[i]), a);
} else {
dst = locmem(argoff, rsp, NULL, arg->mode);
arg = inri(s, arg);
stor(s, arg, dst);
}
argoff += size(n->expr.args[i]);
}
call(s, n->expr.args[0]);
if (argsz)
g(s, Iadd, stkbump, rsp, NULL);
if (retloc) {
if (isfloatmode(retloc->mode))
g(s, Imovs, retloc, ret, NULL);
else
g(s, Imov, retloc, ret, NULL);
}
return ret;
}
Loc *selexpr(Isel *s, Node *n)
{
Loc *a, *b, *c, *d, *r;
Loc *eax, *edx, *cl; /* x86 wants some hard-coded regs */
Node **args;
size_t al;
args = n->expr.args;
eax = locphysreg(Reax);
edx = locphysreg(Redx);
cl = locphysreg(Rcl);
r = NULL;
switch (exprop(n)) {
case Oadd: r = binop(s, Iadd, args[0], args[1]); break;
case Osub: r = binop(s, Isub, args[0], args[1]); break;
case Obor: r = binop(s, Ior, args[0], args[1]); break;
case Oband: r = binop(s, Iand, args[0], args[1]); break;
case Obxor: r = binop(s, Ixor, args[0], args[1]); break;
case Omul:
if (size(args[0]) == 1) {
a = selexpr(s, args[0]);
b = selexpr(s, args[1]);
c = locphysreg(Ral);
r = locreg(a->mode);
g(s, Imov, a, c, NULL);
g(s, Iimul_r, b, NULL);
g(s, Imov, c, r, NULL);
} else {
r = binop(s, Iimul, args[0], args[1]);
}
break;
case Odiv:
case Omod:
/* these get clobbered by the div insn */
a = selexpr(s, args[0]);
b = selexpr(s, args[1]);
b = newr(s, b);
c = coreg(Reax, mode(n));
r = locreg(a->mode);
if (r->mode == ModeB)
g(s, Ixor, eax, eax, NULL);
else
g(s, Ixor, edx, edx, NULL);
g(s, Imov, a, c, NULL);
g(s, Idiv, b, NULL);
if (exprop(n) == Odiv)
d = coreg(Reax, mode(n));
else if (r->mode != ModeB)
d = coreg(Redx, mode(n));
else
d = locphysreg(Rah);
g(s, Imov, d, r, NULL);
break;
case Oneg:
r = selexpr(s, args[0]);
r = newr(s, r);
g(s, Ineg, r, NULL);
break;
/* fp expressions */
case Ofadd: r = binop(s, Iadds, args[0], args[1]); break;
case Ofsub: r = binop(s, Isubs, args[0], args[1]); break;
case Ofmul: r = binop(s, Imuls, args[0], args[1]); break;
case Ofdiv: r = binop(s, Idivs, args[0], args[1]); break;
case Ofneg:
r = selexpr(s, args[0]);
r = newr(s, r);
a = NULL;
b = NULL;
if (mode(args[0]) == ModeF) {
a = locreg(ModeF);
b = loclit(1LL << (31), ModeF);
g(s, Imovs, r, a);
} else if (mode(args[0]) == ModeD) {
a = locreg(ModeQ);
b = loclit(1LL << 63, ModeQ);
g(s, Imov, r, a, NULL);
}
g(s, Ixor, b, a, NULL);
g(s, Imov, a, r, NULL);
break;
case Obsl:
case Obsr:
a = newr(s, selexpr(s, args[0]));
b = selexpr(s, args[1]);
if (b->type == Loclit) {
d = b;
} else {
c = coreg(Rcl, b->mode);
g(s, Imov, b, c, NULL);
d = cl;
}
if (exprop(n) == Obsr) {
if (istysigned(n->expr.type))
g(s, Isar, d, a, NULL);
else
g(s, Ishr, d, a, NULL);
} else {
g(s, Ishl, d, a, NULL);
}
r = a;
break;
case Obnot:
r = selexpr(s, args[0]);
r = newr(s, r);
g(s, Inot, r, NULL);
break;
case Oderef:
r = memloc(s, args[0], mode(n));
break;
case Oaddr:
a = selexpr(s, args[0]);
if (a->type == Loclbl || (a->type == Locmeml && !a->mem.base)) {
r = loclitl(a->lbl);
} else {
r = locreg(ModeQ);
g(s, Ilea, a, r, NULL);
}
break;
case Olnot:
a = newr(s, selexpr(s, args[0]));
b = locreg(ModeB);
r = locreg(mode(n));
/* lnot only valid for integer-like values */
g(s, reloptab[exprop(n)].test, a, a, NULL);
g(s, reloptab[exprop(n)].getflag, b, NULL);
movz(s, b, r);
break;
case Oeq: case One: case Ogt: case Oge: case Olt: case Ole:
case Ofeq: case Ofne: case Ofgt: case Ofge: case Oflt: case Ofle:
case Oueq: case Oune: case Ougt: case Ouge: case Oult: case Oule:
a = selexpr(s, args[0]);
b = selexpr(s, args[1]);
a = newr(s, a);
c = locreg(ModeB);
r = locreg(mode(n));
g(s, reloptab[exprop(n)].test, b, a, NULL);
g(s, reloptab[exprop(n)].getflag, c, NULL);
movz(s, c, r);
return r;
case Oasn: /* relabel */
die("Unimplemented op %s", opstr(exprop(n)));
break;
case Oset:
assert(exprop(args[0]) == Ovar || exprop(args[0]) == Oderef);
assert(!stacknode(args[0]));
b = selexpr(s, args[1]);
if (exprop(args[0]) == Oderef)
a = memloc(s, args[0]->expr.args[0], mode(n));
else
a = selexpr(s, args[0]);
b = inri(s, b);
if (isfloatmode(b->mode))
g(s, Imovs, b, a, NULL);
else
g(s, Imov, b, a, NULL);
r = b;
break;
case Ocall:
r = gencall(s, n);
break;
case Ojmp:
g(s, Ijmp, a = loclbl(args[0]), NULL);
break;
case Ocjmp:
selcjmp(s, n, args);
break;
case Olit: /* fall through */
r = loc(s, n);
break;
case Ovar:
if (isconstfunc(s, n)) {
r = locreg(ModeQ);
a = loc(s, n);
g(s, Ilea, a, r, NULL);
} else {
r = loc(s, n);
}
break;
case Olbl:
r = loclbl(args[0]);
break;
case Oblit:
a = selexpr(s, args[0]);
r = selexpr(s, args[1]);
al = alignto(1, args[0]->expr.type->sub[0]);
blit(s, a, r, 0, 0, args[2]->expr.args[0]->lit.intval, al);
break;
case Otrunc:
a = selexpr(s, args[0]);
a = inr(s, a);
r = locreg(mode(n));
g(s, Imov, a, r, NULL);
break;
case Ozwiden:
a = selexpr(s, args[0]);
a = inr(s, a);
r = locreg(mode(n));
movz(s, a, r);
break;
case Oswiden:
a = selexpr(s, args[0]);
a = inr(s, a);
r = locreg(mode(n));
g(s, Imovsx, a, r, NULL);
break;
case Oint2flt:
a = selexpr(s, args[0]);
b = locreg(ModeQ);
r = locreg(mode(n));
g(s, Imovs, a, b, NULL);
g(s, Icvttsi2sd, b, r, NULL);
break;
case Oflt2int:
a = selexpr(s, args[0]);
b = locreg(ModeQ);
r = locreg(mode(n));
g(s, Icvttsd2si, a, b, NULL);
g(s, Imov, b, r, NULL);
break;
/* These operators should never show up in the reduced trees,
* since they should have been replaced with more primitive
* expressions by now */
case Obad: case Oret: case Opreinc: case Opostinc: case Opredec:
case Opostdec: case Olor: case Oland: case Oaddeq:
case Osubeq: case Omuleq: case Odiveq: case Omodeq: case Oboreq:
case Obandeq: case Obxoreq: case Obsleq: case Obsreq: case Omemb:
case Oslice: case Oidx: case Osize: case Numops:
case Oucon: case Ouget: case Otup: case Oarr: case Ostruct:
case Oslbase: case Osllen: case Ocast:
case Obreak: case Ocontinue:
dump(n, stdout);
die("Should not see %s in isel", opstr(exprop(n)));
break;
}
return r;
}
void locprint(FILE *fd, Loc *l, char spec)
{
assert(l->mode);
switch (l->type) {
case Loclitl:
assert(spec == 'i' || spec == 'x' || spec == 'u');
fprintf(fd, "$%s", l->lbl);
break;
case Loclbl:
assert(spec == 'm' || spec == 'v' || spec == 'x');
fprintf(fd, "%s", l->lbl);
break;
case Locreg:
assert((spec == 'r' && isintmode(l->mode)) ||
(spec == 'f' && isfloatmode(l->mode)) ||
spec == 'v' ||
spec == 'x' ||
spec == 'u');
if (l->reg.colour == Rnone)
fprintf(fd, "%%P.%zd", l->reg.id);
else
fprintf(fd, "%s", regnames[l->reg.colour]);
break;
case Locmem:
case Locmeml:
assert(spec == 'm' || spec == 'v' || spec == 'x');
if (l->type == Locmem) {
if (l->mem.constdisp)
fprintf(fd, "%ld", l->mem.constdisp);
} else {
if (l->mem.lbldisp)
fprintf(fd, "%s", l->mem.lbldisp);
}
if (l->mem.base) {
fprintf(fd, "(");
locprint(fd, l->mem.base, 'r');
if (l->mem.idx) {
fprintf(fd, ",");
locprint(fd, l->mem.idx, 'r');
}
if (l->mem.scale > 1)
fprintf(fd, ",%d", l->mem.scale);
if (l->mem.base)
fprintf(fd, ")");
} else if (l->type != Locmeml) {
die("Only locmeml can have unspecified base reg");
}
break;
case Loclit:
assert(spec == 'i' || spec == 'x' || spec == 'u');
fprintf(fd, "$%ld", l->lit);
break;
case Locnone:
die("Bad location in locprint()");
break;
}
}
int subreg(Loc *a, Loc *b)
{
return rclass(a) == rclass(b) && a->mode != b->mode;
}
void iprintf(FILE *fd, Insn *insn)
{
char *p;
int i;
int modeidx;
/* x64 has a quirk; it has no movzlq because mov zero extends. This
* means that we need to do a movl when we really want a movzlq. Since
* we don't know the name of the reg to use, we need to sub it in when
* writing... */
switch (insn->op) {
case Imovzx:
if (insn->args[0]->mode == ModeL && insn->args[1]->mode == ModeQ) {
if (insn->args[1]->reg.colour) {
insn->op = Imov;
insn->args[1] = coreg(insn->args[1]->reg.colour, ModeL);
}
}
break;
case Imovs:
/* moving a reg to itself is dumb. */
if (insn->args[0]->reg.colour == insn->args[1]->reg.colour)
return;
break;
case Imov:
assert(!isfloatmode(insn->args[1]->mode));
if (insn->args[0]->type != Locreg || insn->args[1]->type != Locreg)
break;
if (insn->args[0]->reg.colour == Rnone || insn->args[1]->reg.colour == Rnone)
break;
/* if one reg is a subreg of another, we can just use the right
* mode to move between them. */
if (subreg(insn->args[0], insn->args[1]))
insn->args[0] = coreg(insn->args[0]->reg.colour, insn->args[1]->mode);
/* moving a reg to itself is dumb. */
if (insn->args[0]->reg.colour == insn->args[1]->reg.colour)
return;
break;
default:
break;
}
p = insnfmts[insn->op];
i = 0;
modeidx = 0;
for (; *p; p++) {
if (*p != '%') {
fputc(*p, fd);
continue;
}
/* %-formating */
p++;
switch (*p) {
case '\0':
goto done; /* skip the final p++ */
case 'r': /* int register */
case 'f': /* float register */
case 'm': /* memory */
case 'i': /* imm */
case 'v': /* reg/mem */
case 'u': /* reg/imm */
case 'x': /* reg/mem/imm */
locprint(fd, insn->args[i], *p);
i++;
break;
case 't':
default:
/* the asm description uses 1-based indexing, so that 0
* can be used as a sentinel. */
if (isdigit(*p))
modeidx = strtol(p, &p, 10) - 1;
if (*p == 't')
fputs(modenames[insn->args[modeidx]->mode], fd);
else
die("Invalid %%-specifier '%c'", *p);
break;
}
}
done:
return;
}
static void isel(Isel *s, Node *n)
{
switch (n->type) {
case Nexpr:
selexpr(s, n);
break;
case Ndecl:
break;
default:
die("Bad node type in isel()");
break;
}
}
Reg savedregs[] = {
Rrcx, Rrdx, Rrbx, Rrsi, Rrdi, Rr8, Rr9, Rr10, Rr11, Rr12, Rr13, Rr14, Rr15,
/*
Rxmm0d, Rxmm1d, Rxmm2d, Rxmm3d, Rxmm4d, Rxmm5d, Rxmm6d, Rxmm7d,
Rxmm8d, Rxmm9d, Rxmm10d, Rxmm11d, Rxmm12d, Rxmm13d, Rxmm14d, Rxmm15d,
*/
};
static void prologue(Isel *s, size_t sz)
{
Loc *rsp;
Loc *rbp;
Loc *stksz;
size_t i;
rsp = locphysreg(Rrsp);
rbp = locphysreg(Rrbp);
stksz = loclit(sz, ModeQ);
/* enter function */
g(s, Ipush, rbp, NULL);
g(s, Imov, rsp, rbp, NULL);
g(s, Isub, stksz, rsp, NULL);
/* save registers */
for (i = 0; i < sizeof(savedregs)/sizeof(savedregs[0]); i++) {
s->calleesave[i] = locreg(ModeQ);
g(s, Imov, locphysreg(savedregs[i]), s->calleesave[i], NULL);
}
s->stksz = stksz; /* need to update if we spill */
}
static void epilogue(Isel *s)
{
Loc *rsp, *rbp;
Loc *ret;
size_t i;
rsp = locphysreg(Rrsp);
rbp = locphysreg(Rrbp);
if (s->ret) {
ret = loc(s, s->ret);
if (floattype(exprtype(s->ret)))
g(s, Imovs, ret, coreg(Rxmm0d, ret->mode), NULL);
else
g(s, Imov, ret, coreg(Rax, ret->mode), NULL);
}
/* restore registers */
for (i = 0; i < Nsaved; i++)
g(s, Imov, s->calleesave[i], locphysreg(savedregs[i]), NULL);
/* leave function */
g(s, Imov, rbp, rsp, NULL);
g(s, Ipop, rbp, NULL);
g(s, Iret, NULL);
}
static void writeasm(FILE *fd, Isel *s, Func *fn)
{
size_t i, j;
if (fn->isexport || !strcmp(fn->name, symprefix "main"))
fprintf(fd, ".globl %s\n", fn->name);
fprintf(fd, "%s:\n", fn->name);
for (j = 0; j < s->cfg->nbb; j++) {
for (i = 0; i < s->bb[j]->nlbls; i++)
fprintf(fd, "%s:\n", s->bb[j]->lbls[i]);
for (i = 0; i < s->bb[j]->ni; i++)
iprintf(fd, s->bb[j]->il[i]);
}
}
static Asmbb *mkasmbb(Bb *bb)
{
Asmbb *as;
as = zalloc(sizeof(Asmbb));
as->id = bb->id;
as->pred = bsdup(bb->pred);
as->succ = bsdup(bb->succ);
as->lbls = memdup(bb->lbls, bb->nlbls*sizeof(char*));
as->nlbls = bb->nlbls;
return as;
}
static void writebytes(FILE *fd, char *p, size_t sz)
{
size_t i;
for (i = 0; i < sz; i++) {
if (i % 60 == 0)
fprintf(fd, "\t.ascii \"");
if (p[i] == '"' || p[i] == '\\')
fprintf(fd, "\\");
if (isprint(p[i]))
fprintf(fd, "%c", p[i]);
else
fprintf(fd, "\\%03o", (uint8_t)p[i] & 0xff);
/* line wrapping for readability */
if (i % 60 == 59 || i == sz - 1)
fprintf(fd, "\"\n");
}
}
static size_t writelit(FILE *fd, Htab *strtab, Node *v, Type *ty)
{
char buf[128];
char *lbl;
size_t sz;
char *intsz[] = {
[1] = ".byte",
[2] = ".short",
[4] = ".long",
[8] = ".quad"
};
union {
float fv;
double dv;
uint64_t qv;
uint32_t lv;
} u;
assert(v->type == Nlit);
sz = tysize(ty);
switch (v->lit.littype) {
case Lint: fprintf(fd, "\t%s %lld\n", intsz[sz], v->lit.intval); break;
case Lbool: fprintf(fd, "\t.byte %d\n", v->lit.boolval); break;
case Lchr: fprintf(fd, "\t.long %d\n", v->lit.chrval); break;
case Lflt:
if (tybase(v->lit.type)->type == Tyfloat32) {
u.fv = v->lit.fltval;
fprintf(fd, "\t.long 0x%"PRIx32"\n", u.lv);
} else if (tybase(v->lit.type)->type == Tyfloat64) {
u.dv = v->lit.fltval;
fprintf(fd, "\t.quad 0x%"PRIx64"\n", u.qv);
}
break;
case Lstr:
if (hthas(strtab, v->lit.strval)) {
lbl = htget(strtab, v->lit.strval);
} else {
lbl = genlblstr(buf, sizeof buf);
htput(strtab, v->lit.strval, strdup(lbl));
}
fprintf(fd, "\t.quad %s\n", lbl);
fprintf(fd, "\t.quad %zd\n", strlen(v->lit.strval));
break;
case Lfunc:
die("Generating this shit ain't ready yet ");
break;
case Llbl:
die("Can't generate literal labels, ffs. They're not data.");
break;
}
return sz;
}
static size_t writepad(FILE *fd, size_t sz)
{
assert((ssize_t)sz >= 0);
if (sz > 0)
fprintf(fd, "\t.fill %zd,1,0\n", sz);
return sz;
}
static size_t getintlit(Node *n, char *failmsg)
{
if (exprop(n) != Olit)
fatal(n->line, "%s", failmsg);
n = n->expr.args[0];
if (n->lit.littype != Lint)
fatal(n->line, "%s", failmsg);
return n->lit.intval;
}
static size_t writeslice(FILE *fd, Htab *globls, Htab *strtab, Node *n)
{
Node *base, *lo, *hi;
ssize_t loval, hival, sz;
char *lbl;
base = n->expr.args[0];
lo = n->expr.args[1];
hi = n->expr.args[2];
/* by this point, all slicing operations should have had their bases
* pulled out, and we should have vars with their pseudo-decls in their
* place */
if (exprop(base) != Ovar || !base->expr.isconst)
fatal(base->line, "slice base is not a constant value");
loval = getintlit(lo, "lower bound in slice is not constant literal");
hival = getintlit(hi, "upper bound in slice is not constant literal");
sz = tysize(tybase(exprtype(base))->sub[0]);
lbl = htget(globls, base);
fprintf(fd, "\t.quad %s + (%zd*%zd)\n", lbl, loval, sz);
fprintf(fd, "\t.quad %zd\n", (hival - loval));
return size(n);
}
static size_t writestruct(FILE *fd, Htab *globls, Htab *strtab, Node *n)
{
Type *t;
Node **dcl;
int found;
size_t i, j;
size_t sz, pad, end;
size_t ndcl;
sz = 0;
t = tybase(exprtype(n));
assert(t->type == Tystruct);
dcl = t->sdecls;
ndcl = t->nmemb;
for (i = 0; i < ndcl; i++) {
pad = alignto(sz, decltype(dcl[i]));
sz += writepad(fd, pad - sz);
found = 0;
for (j = 0; j < n->expr.nargs; j++)
if (!strcmp(namestr(n->expr.args[j]->expr.idx), declname(dcl[i]))) {
found = 1;
sz += writeblob(fd, globls, strtab, n->expr.args[j]);
}
if (!found)
sz += writepad(fd, size(dcl[i]));
}
end = alignto(sz, t);
sz += writepad(fd, end - sz);
return sz;
}
static size_t writeblob(FILE *fd, Htab *globls, Htab *strtab, Node *n)
{
size_t i, sz;
switch(exprop(n)) {
case Otup:
case Oarr:
sz = 0;
for (i = 0; i < n->expr.nargs; i++)
sz += writeblob(fd, globls, strtab, n->expr.args[i]);
break;
case Ostruct:
sz = writestruct(fd, globls, strtab, n);
break;
case Olit:
sz = writelit(fd, strtab, n->expr.args[0], exprtype(n));
break;
case Oslice:
sz = writeslice(fd, globls, strtab, n);
break;
default:
dump(n, stdout);
die("Nonliteral initializer for global");
break;
}
return sz;
}
void genblob(FILE *fd, Node *blob, Htab *globls, Htab *strtab)
{
char *lbl;
/* lits and such also get wrapped in decls */
assert(blob->type == Ndecl);
lbl = htget(globls, blob);
if (blob->decl.vis != Visintern)
fprintf(fd, ".globl %s\n", lbl);
fprintf(fd, "%s:\n", lbl);
if (blob->decl.init)
writeblob(fd, globls, strtab, blob->decl.init);
else
writepad(fd, size(blob));
}
/* genasm requires all nodes in 'nl' to map cleanly to operations that are
* natively supported, as promised in the output of reduce(). No 64-bit
* operations on x32, no structures, and so on. */
void genasm(FILE *fd, Func *fn, Htab *globls, Htab *strtab)
{
Isel is = {0,};
size_t i, j;
char buf[128];
is.reglocs = mkht(varhash, vareq);
is.stkoff = fn->stkoff;
is.globls = globls;
is.ret = fn->ret;
is.cfg = fn->cfg;
/* ensure that all physical registers have a loc created, so we
* don't get any surprises referring to them in the allocator */
for (i = 0; i < Nreg; i++)
locphysreg(i);
for (i = 0; i < fn->cfg->nbb; i++)
lappend(&is.bb, &is.nbb, mkasmbb(fn->cfg->bb[i]));
is.curbb = is.bb[0];
prologue(&is, fn->stksz);
for (j = 0; j < fn->cfg->nbb - 1; j++) {
is.curbb = is.bb[j];
for (i = 0; i < fn->cfg->bb[j]->nnl; i++) {
/* put in a comment that says where this line comes from */
snprintf(buf, sizeof buf, "\n\t# bb = %zd, bbidx = %zd, %s:%d",
j, i, file->file.name, fn->cfg->bb[j]->nl[i]->line);
g(&is, Ilbl, locstrlbl(buf), NULL);
isel(&is, fn->cfg->bb[j]->nl[i]);
}
}
is.curbb = is.bb[is.nbb - 1];
epilogue(&is);
regalloc(&is);
if (debugopt['i'])
writeasm(stdout, &is, fn);
writeasm(fd, &is, fn);
}
void genstrings(FILE *fd, Htab *strtab)
{
void **k;
size_t i, nk;
k = htkeys(strtab, &nk);
for (i = 0; i < nk; i++) {
fprintf(fd, "%s:\n", (char*)htget(strtab, k[i]));
writebytes(fd, k[i], strlen(k[i]));
}
}