ref: e09adf59442cd36888eaea1d76e66ff3259d16b8
dir: /sys/src/cmd/vl/noop.c/
#include "l.h" void noops(void) { Prog *p, *p1, *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 |= LABEL|LEAF|SYNC; if(p->link) p->link->mark |= LABEL; curtext = p; break; /* too hard, just leave alone */ case AMOVW: if(p->to.type == D_FCREG || p->to.type == D_MREG) { p->mark |= LABEL|SYNC; break; } if(p->from.type == D_FCREG || p->from.type == D_MREG) { p->mark |= LABEL|SYNC; addnop(p); addnop(p); nop.mfrom.count += 2; nop.mfrom.outof += 2; break; } break; /* too hard, just leave alone */ case ACASE: case ASYSCALL: case AWORD: case ATLBWR: case ATLBWI: case ATLBP: case ATLBR: p->mark |= LABEL|SYNC; break; case ANOR: if(p->to.type == D_REG && p->to.reg == REGZERO) p->mark |= LABEL|SYNC; break; case ARET: /* special form of RET is BECOME */ if(p->from.type == D_CONST) if(p->from.offset > curbecome) curbecome = p->from.offset; if(p->link != P) p->link->mark |= LABEL; break; case ANOP: q1 = p->link; q->link = q1; /* q is non-nop */ q1->mark |= p->mark; continue; case ABCASE: p->mark |= LABEL|SYNC; goto dstlab; case ABGEZAL: case ABLTZAL: case AJAL: if(curtext != P) curtext->mark &= ~LEAF; case AJMP: case ABEQ: case ABGEZ: case ABGTZ: case ABLEZ: case ABLTZ: case ABNE: case ABFPT: case ABFPF: p->mark |= BRANCH; dstlab: q1 = p->cond; if(q1 != P) { while(q1->as == ANOP) { q1 = q1->link; p->cond = q1; } if(!(q1->mark & LEAF)) q1->mark |= LABEL; } else p->mark |= LABEL; q1 = p->link; if(q1 != P) q1->mark |= LABEL; 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 AJAL: 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; } q = p; if(autosize) { q = prg(); q->as = AADD; 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; } else if(!(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; break; } q1 = prg(); q1->as = AMOVW; q1->line = p->line; q1->from.type = D_REG; q1->from.reg = REGLINK; q1->to.type = D_OREG; q1->from.offset = 0; q1->to.reg = REGSP; q1->link = q->link; q->link = q1; break; case ARET: nocache(p); if(p->from.type == D_CONST) goto become; if(curtext->mark & LEAF) { if(!autosize) { p->as = AJMP; p->from = zprg.from; p->to.type = D_OREG; p->to.offset = 0; p->to.reg = REGLINK; p->mark |= BRANCH; break; } 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 = AJMP; q->line = p->line; q->to.type = D_OREG; q->to.offset = 0; q->to.reg = REGLINK; q->mark |= BRANCH; q->link = p->link; p->link = q; break; } p->as = AMOVW; p->from.type = D_OREG; p->from.offset = 0; p->from.reg = REGSP; p->to.type = D_REG; p->to.reg = 2; q = p; if(autosize) { q = prg(); q->as = AADD; 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; } q1 = prg(); q1->as = AJMP; q1->line = p->line; q1->to.type = D_OREG; q1->to.offset = 0; q1->to.reg = 2; q1->mark |= BRANCH; q1->link = q->link; q->link = q1; break; become: if(curtext->mark & LEAF) { q = prg(); q->line = p->line; q->as = AJMP; q->from = zprg.from; q->to = p->to; q->cond = p->cond; q->link = p->link; q->mark |= BRANCH; 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; } q = prg(); q->line = p->line; q->as = AJMP; q->from = zprg.from; q->to = p->to; q->cond = p->cond; q->link = p->link; q->mark |= BRANCH; p->link = q; q = prg(); q->line = p->line; q->as = AADD; 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; p->as = AMOVW; p->from = zprg.from; p->from.type = D_OREG; p->from.offset = 0; p->from.reg = REGSP; p->to = zprg.to; p->to.type = D_REG; p->to.reg = REGLINK; break; } } curtext = P; q = P; /* p - 1 */ q1 = firstp; /* top of block */ o = 0; /* count of instructions */ for(p = firstp; p != P; p = p1) { p1 = p->link; o++; if(p->mark & NOSCHED){ if(q1 != p){ sched(q1, q); } for(; p != P; p = p->link){ if(!(p->mark & NOSCHED)) break; q = p; } p1 = p; q1 = p; o = 0; continue; } if(p->mark & (LABEL|SYNC)) { if(q1 != p) sched(q1, q); q1 = p; o = 1; } if(p->mark & (BRANCH|SYNC)) { sched(q1, p); q1 = p1; o = 0; } if(o >= NSCHED) { sched(q1, p); q1 = p1; o = 0; } q = p; } } void addnop(Prog *p) { Prog *q; q = prg(); q->as = ANOR; q->line = p->line; q->from.type = D_REG; q->from.reg = REGZERO; q->to.type = D_REG; q->to.reg = REGZERO; q->link = p->link; p->link = q; } void nocache(Prog *p) { p->optab = 0; p->from.class = 0; p->to.class = 0; }