ref: cbe4b116989c0bfec49b9ae7a1d9a85ead6648ae
dir: /sys/src/cmd/5l/noop.c/
#include "l.h"
static Sym* sym_div;
static Sym* sym_divu;
static Sym* sym_mod;
static Sym* sym_modu;
void
noops(void)
{
Prog *p, *q, *q1;
int o, curframe, curbecome, maxbecome;
/*
* find leaf subroutines
* become sizes
* frame sizes
* strip NOPs
* expand RET
* expand BECOME pseudo
*/
if(debug['v'])
Bprint(&bso, "%5.2f noops\n", cputime());
Bflush(&bso);
curframe = 0;
curbecome = 0;
maxbecome = 0;
curtext = 0;
q = P;
for(p = firstp; p != P; p = p->link) {
/* find out how much arg space is used in this TEXT */
if(p->to.type == D_OREG && p->to.reg == REGSP)
if(p->to.offset > curframe)
curframe = p->to.offset;
switch(p->as) {
case ATEXT:
if(curtext && curtext->from.sym) {
curtext->from.sym->frame = curframe;
curtext->from.sym->become = curbecome;
if(curbecome > maxbecome)
maxbecome = curbecome;
}
curframe = 0;
curbecome = 0;
p->mark |= LEAF;
curtext = p;
break;
case ARET:
/* special form of RET is BECOME */
if(p->from.type == D_CONST)
if(p->from.offset > curbecome)
curbecome = p->from.offset;
break;
case ADIV:
case ADIVU:
case AMOD:
case AMODU:
q = p;
if(prog_div == P)
initdiv();
if(curtext != P)
curtext->mark &= ~LEAF;
continue;
case ANOP:
q1 = p->link;
q->link = q1; /* q is non-nop */
q1->mark |= p->mark;
continue;
case ABL:
if(curtext != P)
curtext->mark &= ~LEAF;
case ABCASE:
case AB:
case ABEQ:
case ABNE:
case ABCS:
case ABHS:
case ABCC:
case ABLO:
case ABMI:
case ABPL:
case ABVS:
case ABVC:
case ABHI:
case ABLS:
case ABGE:
case ABLT:
case ABGT:
case ABLE:
q1 = p->cond;
if(q1 != P) {
while(q1->as == ANOP) {
q1 = q1->link;
p->cond = q1;
}
}
break;
}
q = p;
}
if(curtext && curtext->from.sym) {
curtext->from.sym->frame = curframe;
curtext->from.sym->become = curbecome;
if(curbecome > maxbecome)
maxbecome = curbecome;
}
if(debug['b'])
print("max become = %d\n", maxbecome);
xdefine("ALEFbecome", STEXT, maxbecome);
curtext = 0;
for(p = firstp; p != P; p = p->link) {
switch(p->as) {
case ATEXT:
curtext = p;
break;
case ABL:
if(curtext != P && curtext->from.sym != S && curtext->to.offset >= 0) {
o = maxbecome - curtext->from.sym->frame;
if(o <= 0)
break;
/* calling a become or calling a variable */
if(p->to.sym == S || p->to.sym->become) {
curtext->to.offset += o;
if(debug['b']) {
curp = p;
print("%D calling %D increase %d\n",
&curtext->from, &p->to, o);
}
}
}
break;
}
}
for(p = firstp; p != P; p = p->link) {
o = p->as;
switch(o) {
case ATEXT:
curtext = p;
autosize = p->to.offset + 4;
if(autosize <= 4)
if(curtext->mark & LEAF) {
p->to.offset = -4;
autosize = 0;
}
if(!autosize && !(curtext->mark & LEAF)) {
if(debug['v'])
Bprint(&bso, "save suppressed in: %s\n",
curtext->from.sym->name);
Bflush(&bso);
curtext->mark |= LEAF;
}
if(curtext->mark & LEAF) {
if(curtext->from.sym)
curtext->from.sym->type = SLEAF;
#ifdef optimise_time
if(autosize) {
q = prg();
q->as = ASUB;
q->line = p->line;
q->from.type = D_CONST;
q->from.offset = autosize;
q->to.type = D_REG;
q->to.reg = REGSP;
q->link = p->link;
p->link = q;
}
break;
#else
if(!autosize)
break;
#endif
}
q1 = prg();
q1->as = AMOVW;
q1->scond |= C_WBIT;
q1->line = p->line;
q1->from.type = D_REG;
q1->from.reg = REGLINK;
q1->to.type = D_OREG;
q1->to.offset = -autosize;
q1->to.reg = REGSP;
q1->link = p->link;
p->link = q1;
break;
case ARET:
nocache(p);
if(p->from.type == D_CONST)
goto become;
if(curtext->mark & LEAF) {
if(!autosize) {
p->as = AB;
p->from = zprg.from;
p->to.type = D_OREG;
p->to.offset = 0;
p->to.reg = REGLINK;
break;
}
#ifdef optimise_time
p->as = AADD;
p->from.type = D_CONST;
p->from.offset = autosize;
p->to.type = D_REG;
p->to.reg = REGSP;
q = prg();
q->as = AB;
q->scond = p->scond;
q->line = p->line;
q->to.type = D_OREG;
q->to.offset = 0;
q->to.reg = REGLINK;
q->link = p->link;
p->link = q;
break;
#endif
}
p->as = AMOVW;
p->scond |= C_PBIT;
p->from.type = D_OREG;
p->from.offset = autosize;
p->from.reg = REGSP;
p->to.type = D_REG;
p->to.reg = REGPC;
break;
become:
if(curtext->mark & LEAF) {
if(!autosize) {
p->as = AB;
p->from = zprg.from;
break;
}
#ifdef optimise_time
q = prg();
q->scond = p->scond;
q->line = p->line;
q->as = AB;
q->from = zprg.from;
q->to = p->to;
q->cond = p->cond;
q->link = p->link;
p->link = q;
p->as = AADD;
p->from = zprg.from;
p->from.type = D_CONST;
p->from.offset = autosize;
p->to = zprg.to;
p->to.type = D_REG;
p->to.reg = REGSP;
break;
#endif
}
q = prg();
q->scond = p->scond;
q->line = p->line;
q->as = AB;
q->from = zprg.from;
q->to = p->to;
q->cond = p->cond;
q->link = p->link;
p->link = q;
p->as = AMOVW;
p->scond |= C_PBIT;
p->from = zprg.from;
p->from.type = D_OREG;
p->from.offset = autosize;
p->from.reg = REGSP;
p->to = zprg.to;
p->to.type = D_REG;
p->to.reg = REGLINK;
break;
/*
* 5c code generation for unsigned -> double made the
* unfortunate assumption that single and double floating
* point registers are aliased - true for emulated 7500
* but not for vfp. Now corrected, but this test is
* insurance against old 5c compiled code in libraries.
*/
case AMOVWD:
if((q = p->link) != P && q->as == ACMP)
if((q = q->link) != P && q->as == AMOVF)
if((q1 = q->link) != P && q1->as == AADDF)
if(q1->to.type == D_FREG && q1->to.reg == p->to.reg) {
q1->as = AADDD;
q1 = prg();
q1->scond = q->scond;
q1->line = q->line;
q1->as = AMOVFD;
q1->from = q->to;
q1->to = q1->from;
q1->link = q->link;
q->link = q1;
}
break;
case ADIV:
case ADIVU:
case AMOD:
case AMODU:
if(debug['M'])
break;
if(p->from.type != D_REG)
break;
if(p->to.type != D_REG)
break;
q1 = p;
/* MOV a,4(SP) */
q = prg();
q->link = p->link;
p->link = q;
p = q;
p->as = AMOVW;
p->line = q1->line;
p->from.type = D_REG;
p->from.reg = q1->from.reg;
p->to.type = D_OREG;
p->to.reg = REGSP;
p->to.offset = 4;
/* MOV b,REGTMP */
q = prg();
q->link = p->link;
p->link = q;
p = q;
p->as = AMOVW;
p->line = q1->line;
p->from.type = D_REG;
p->from.reg = q1->reg;
if(q1->reg == NREG)
p->from.reg = q1->to.reg;
p->to.type = D_REG;
p->to.reg = REGTMP;
p->to.offset = 0;
/* CALL appropriate */
q = prg();
q->link = p->link;
p->link = q;
p = q;
p->as = ABL;
p->line = q1->line;
p->to.type = D_BRANCH;
p->cond = p;
switch(o) {
case ADIV:
p->cond = prog_div;
p->to.sym = sym_div;
break;
case ADIVU:
p->cond = prog_divu;
p->to.sym = sym_divu;
break;
case AMOD:
p->cond = prog_mod;
p->to.sym = sym_mod;
break;
case AMODU:
p->cond = prog_modu;
p->to.sym = sym_modu;
break;
}
/* MOV REGTMP, b */
q = prg();
q->link = p->link;
p->link = q;
p = q;
p->as = AMOVW;
p->line = q1->line;
p->from.type = D_REG;
p->from.reg = REGTMP;
p->from.offset = 0;
p->to.type = D_REG;
p->to.reg = q1->to.reg;
/* ADD $8,SP */
q = prg();
q->link = p->link;
p->link = q;
p = q;
p->as = AADD;
p->from.type = D_CONST;
p->from.reg = NREG;
p->from.offset = 8;
p->reg = NREG;
p->to.type = D_REG;
p->to.reg = REGSP;
/* SUB $8,SP */
q1->as = ASUB;
q1->from.type = D_CONST;
q1->from.offset = 8;
q1->from.reg = NREG;
q1->reg = NREG;
q1->to.type = D_REG;
q1->to.reg = REGSP;
break;
}
}
}
static void
sigdiv(char *n)
{
Sym *s;
s = lookup(n, 0);
if(s->type == STEXT){
if(s->sig == 0)
s->sig = SIGNINTERN;
}
else if(s->type == 0 || s->type == SXREF)
s->type = SUNDEF;
}
void
divsig(void)
{
sigdiv("_div");
sigdiv("_divu");
sigdiv("_mod");
sigdiv("_modu");
}
static void
sdiv(Sym *s)
{
if(s->type == 0 || s->type == SXREF){
/* undefsym(s); */
s->type = SXREF;
if(s->sig == 0)
s->sig = SIGNINTERN;
s->subtype = SIMPORT;
}
else if(s->type != STEXT)
diag("undefined: %s", s->name);
}
void
initdiv(void)
{
Sym *s2, *s3, *s4, *s5;
Prog *p;
if(prog_div != P)
return;
sym_div = s2 = lookup("_div", 0);
sym_divu = s3 = lookup("_divu", 0);
sym_mod = s4 = lookup("_mod", 0);
sym_modu = s5 = lookup("_modu", 0);
if(dlm) {
sdiv(s2); if(s2->type == SXREF) prog_div = UP;
sdiv(s3); if(s3->type == SXREF) prog_divu = UP;
sdiv(s4); if(s4->type == SXREF) prog_mod = UP;
sdiv(s5); if(s5->type == SXREF) prog_modu = UP;
}
for(p = firstp; p != P; p = p->link)
if(p->as == ATEXT) {
if(p->from.sym == s2)
prog_div = p;
if(p->from.sym == s3)
prog_divu = p;
if(p->from.sym == s4)
prog_mod = p;
if(p->from.sym == s5)
prog_modu = p;
}
if(prog_div == P) {
diag("undefined: %s", s2->name);
prog_div = curtext;
}
if(prog_divu == P) {
diag("undefined: %s", s3->name);
prog_divu = curtext;
}
if(prog_mod == P) {
diag("undefined: %s", s4->name);
prog_mod = curtext;
}
if(prog_modu == P) {
diag("undefined: %s", s5->name);
prog_modu = curtext;
}
}
void
nocache(Prog *p)
{
p->optab = 0;
p->from.class = 0;
p->to.class = 0;
}