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go/src/cmd/5l/noop.c
Shenghou Ma 0cb04168d3 cmd/5l: dwarf line number support for Linux/ARM 
Part of issue 3747.

R=dave, lvd, rsc
CC=golang-dev
https://golang.org/cl/6084044
2012-08-07 10:09:24 +08:00

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// Inferno utils/5l/noop.c
// http://code.google.com/p/inferno-os/source/browse/utils/5l/noop.c
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
// Portions Copyright © 1997-1999 Vita Nuova Limited
// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
// Portions Copyright © 2004,2006 Bruce Ellis
// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
// Portions Copyright © 2009 The Go Authors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
// Code transformations.
#include "l.h"
#include "../ld/lib.h"
// see ../../runtime/proc.c:/StackGuard
enum
{
StackBig = 4096,
StackSmall = 128,
};
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;
Prog *pmorestack;
Sym *symmorestack;
/*
* find leaf subroutines
* strip NOPs
* expand RET
* expand BECOME pseudo
*/
if(debug['v'])
Bprint(&bso, "%5.2f noops\n", cputime());
Bflush(&bso);
symmorestack = lookup("runtime.morestack", 0);
if(symmorestack->type != STEXT) {
diag("runtime·morestack not defined");
errorexit();
}
pmorestack = symmorestack->text;
pmorestack->reg |= NOSPLIT;
q = P;
for(cursym = textp; cursym != nil; cursym = cursym->next) {
for(p = cursym->text; p != P; p = p->link) {
switch(p->as) {
case ATEXT:
p->mark |= LEAF;
break;
case ARET:
break;
case ADIV:
case ADIVU:
case AMOD:
case AMODU:
q = p;
if(prog_div == P)
initdiv();
cursym->text->mark &= ~LEAF;
continue;
case ANOP:
q1 = p->link;
q->link = q1; /* q is non-nop */
if(q1 != P)
q1->mark |= p->mark;
continue;
case ABL:
case ABX:
cursym->text->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;
}
}
for(cursym = textp; cursym != nil; cursym = cursym->next) {
for(p = cursym->text; p != P; p = p->link) {
o = p->as;
switch(o) {
case ATEXT:
autosize = p->to.offset + 4;
if(autosize <= 4)
if(cursym->text->mark & LEAF) {
p->to.offset = -4;
autosize = 0;
}
if(!autosize && !(cursym->text->mark & LEAF)) {
if(debug['v'])
Bprint(&bso, "save suppressed in: %s\n",
cursym->name);
Bflush(&bso);
cursym->text->mark |= LEAF;
}
if(cursym->text->mark & LEAF) {
cursym->leaf = 1;
if(!autosize)
break;
}
if(p->reg & NOSPLIT) {
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->spadj = autosize;
q1->link = p->link;
p->link = q1;
} else if (autosize < StackBig) {
// split stack check for small functions
// MOVW g_stackguard(g), R1
// CMP R1, $-autosize(SP)
// MOVW.LO $autosize, R1
// MOVW.LO $args, R2
// MOVW.LO R14, R3
// BL.LO runtime.morestack(SB) // modifies LR
// MOVW.W R14,$-autosize(SP)
// TODO(kaib): add more trampolines
// TODO(kaib): put stackguard in register
// TODO(kaib): add support for -K and underflow detection
// MOVW g_stackguard(g), R1
p = appendp(p);
p->as = AMOVW;
p->from.type = D_OREG;
p->from.reg = REGG;
p->to.type = D_REG;
p->to.reg = 1;
if(autosize < StackSmall) {
// CMP R1, SP
p = appendp(p);
p->as = ACMP;
p->from.type = D_REG;
p->from.reg = 1;
p->reg = REGSP;
} else {
// MOVW $-autosize(SP), R2
// CMP R1, R2
p = appendp(p);
p->as = AMOVW;
p->from.type = D_CONST;
p->from.reg = REGSP;
p->from.offset = -autosize;
p->to.type = D_REG;
p->to.reg = 2;
p = appendp(p);
p->as = ACMP;
p->from.type = D_REG;
p->from.reg = 1;
p->reg = 2;
}
// MOVW.LO $autosize, R1
p = appendp(p);
p->as = AMOVW;
p->scond = C_SCOND_LO;
p->from.type = D_CONST;
p->from.offset = autosize;
p->to.type = D_REG;
p->to.reg = 1;
// MOVW.LO $args, R2
p = appendp(p);
p->as = AMOVW;
p->scond = C_SCOND_LO;
p->from.type = D_CONST;
p->from.offset = (cursym->text->to.offset2 + 3) & ~3;
p->to.type = D_REG;
p->to.reg = 2;
// MOVW.LO R14, R3
p = appendp(p);
p->as = AMOVW;
p->scond = C_SCOND_LO;
p->from.type = D_REG;
p->from.reg = REGLINK;
p->to.type = D_REG;
p->to.reg = 3;
// BL.LO runtime.morestack(SB) // modifies LR
p = appendp(p);
p->as = ABL;
p->scond = C_SCOND_LO;
p->to.type = D_BRANCH;
p->to.sym = symmorestack;
p->cond = pmorestack;
// MOVW.W R14,$-autosize(SP)
p = appendp(p);
p->as = AMOVW;
p->scond |= C_WBIT;
p->from.type = D_REG;
p->from.reg = REGLINK;
p->to.type = D_OREG;
p->to.offset = -autosize;
p->to.reg = REGSP;
p->spadj = autosize;
} else { // > StackBig
// MOVW $autosize, R1
// MOVW $args, R2
// MOVW R14, R3
// BL runtime.morestack(SB) // modifies LR
// MOVW.W R14,$-autosize(SP)
// MOVW $autosize, R1
p = appendp(p);
p->as = AMOVW;
p->from.type = D_CONST;
p->from.offset = autosize;
p->to.type = D_REG;
p->to.reg = 1;
// MOVW $args, R2
// also need to store the extra 4 bytes.
p = appendp(p);
p->as = AMOVW;
p->from.type = D_CONST;
p->from.offset = (cursym->text->to.offset2 + 3) & ~3;
p->to.type = D_REG;
p->to.reg = 2;
// MOVW R14, R3
p = appendp(p);
p->as = AMOVW;
p->from.type = D_REG;
p->from.reg = REGLINK;
p->to.type = D_REG;
p->to.reg = 3;
// BL runtime.morestack(SB) // modifies LR
p = appendp(p);
p->as = ABL;
p->to.type = D_BRANCH;
p->to.sym = symmorestack;
p->cond = pmorestack;
// MOVW.W R14,$-autosize(SP)
p = appendp(p);
p->as = AMOVW;
p->scond |= C_WBIT;
p->from.type = D_REG;
p->from.reg = REGLINK;
p->to.type = D_OREG;
p->to.offset = -autosize;
p->to.reg = REGSP;
p->spadj = autosize;
}
break;
case ARET:
nocache(p);
if(cursym->text->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;
}
}
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;
// If there are instructions following
// this ARET, they come from a branch
// with the same stackframe, so no spadj.
break;
case AADD:
if(p->from.type == D_CONST && p->from.reg == NREG && p->to.type == D_REG && p->to.reg == REGSP)
p->spadj = -p->from.offset;
break;
case ASUB:
if(p->from.type == D_CONST && p->from.reg == NREG && p->to.type == D_REG && p->to.reg == REGSP)
p->spadj = p->from.offset;
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) */
p = appendp(p);
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 */
p = appendp(p);
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 */
p = appendp(p);
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 */
p = appendp(p);
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 */
p = appendp(p);
p->as = AADD;
p->line = q1->line;
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;
p->spadj = -8;
/* 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;
q1->spadj = 8;
break;
case AMOVW:
if((p->scond & C_WBIT) && p->to.type == D_OREG && p->to.reg == REGSP)
p->spadj = -p->to.offset;
if((p->scond & C_PBIT) && p->from.type == D_OREG && p->from.reg == REGSP && p->to.reg != REGPC)
p->spadj = -p->from.offset;
if(p->from.type == D_CONST && p->from.reg == REGSP && p->to.type == D_REG && p->to.reg == REGSP)
p->spadj = -p->from.offset;
break;
}
}
}
}
static void
sigdiv(char *n)
{
Sym *s;
s = lookup(n, 0);
if(s->type == STEXT)
if(s->sig == 0)
s->sig = SIGNINTERN;
}
void
divsig(void)
{
sigdiv("_div");
sigdiv("_divu");
sigdiv("_mod");
sigdiv("_modu");
}
void
initdiv(void)
{
Sym *s2, *s3, *s4, *s5;
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);
prog_div = s2->text;
prog_divu = s3->text;
prog_mod = s4->text;
prog_modu = s5->text;
if(prog_div == P) {
diag("undefined: %s", s2->name);
prog_div = cursym->text;
}
if(prog_divu == P) {
diag("undefined: %s", s3->name);
prog_divu = cursym->text;
}
if(prog_mod == P) {
diag("undefined: %s", s4->name);
prog_mod = cursym->text;
}
if(prog_modu == P) {
diag("undefined: %s", s5->name);
prog_modu = cursym->text;
}
}
void
nocache(Prog *p)
{
p->optab = 0;
p->from.class = 0;
p->to.class = 0;
}
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