// Derived from Inferno utils/5c/swt.c
// http://code.google.com/p/inferno-os/source/browse/utils/5c/swt.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.
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <link.h>
#include "../cmd/5l/5.out.h"
#include "../pkg/runtime/stack.h"
static Prog zprg = {
.as = AGOK,
.scond = C_SCOND_NONE,
.reg = NREG,
.from = {
.name = D_NONE,
.type = D_NONE,
.reg = NREG,
},
.to = {
.name = D_NONE,
.type = D_NONE,
.reg = NREG,
},
};
static int
symtype(Addr *a)
{
return a->name;
}
static int
isdata(Prog *p)
{
return p->as == ADATA || p->as == AGLOBL;
}
static int
iscall(Prog *p)
{
return p->as == ABL;
}
static int
datasize(Prog *p)
{
return p->reg;
}
static int
textflag(Prog *p)
{
return p->reg;
}
static void
settextflag(Prog *p, int f)
{
p->reg = f;
}
static void
progedit(Link *ctxt, Prog *p)
{
char literal[64];
LSym *s;
LSym *tlsfallback;
p->from.class = 0;
p->to.class = 0;
// Rewrite B/BL to symbol as D_BRANCH.
switch(p->as) {
case AB:
case ABL:
case ADUFFZERO:
case ADUFFCOPY:
if(p->to.type == D_OREG && (p->to.name == D_EXTERN || p->to.name == D_STATIC) && p->to.sym != nil)
p->to.type = D_BRANCH;
break;
}
// Replace TLS register fetches on older ARM procesors.
switch(p->as) {
case AMRC:
// If the instruction matches MRC 15, 0, <reg>, C13, C0, 3, replace it.
if(ctxt->goarm < 7 && (p->to.offset & 0xffff0fff) == 0xee1d0f70) {
tlsfallback = linklookup(ctxt, "runtime.read_tls_fallback", 0);
// BL runtime.read_tls_fallback(SB)
p->as = ABL;
p->to.type = D_BRANCH;
p->to.sym = tlsfallback;
p->to.offset = 0;
} else {
// Otherwise, MRC/MCR instructions need no further treatment.
p->as = AWORD;
}
break;
}
// Rewrite float constants to values stored in memory.
switch(p->as) {
case AMOVF:
if(p->from.type == D_FCONST && chipfloat5(ctxt, p->from.u.dval) < 0 &&
(chipzero5(ctxt, p->from.u.dval) < 0 || (p->scond & C_SCOND) != C_SCOND_NONE)) {
int32 i32;
float32 f32;
f32 = p->from.u.dval;
memmove(&i32, &f32, 4);
sprint(literal, "$f32.%08ux", (uint32)i32);
s = linklookup(ctxt, literal, 0);
if(s->type == 0) {
s->type = SRODATA;
adduint32(ctxt, s, i32);
s->reachable = 0;
}
p->from.type = D_OREG;
p->from.sym = s;
p->from.name = D_EXTERN;
p->from.offset = 0;
}
break;
case AMOVD:
if(p->from.type == D_FCONST && chipfloat5(ctxt, p->from.u.dval) < 0 &&
(chipzero5(ctxt, p->from.u.dval) < 0 || (p->scond & C_SCOND) != C_SCOND_NONE)) {
int64 i64;
memmove(&i64, &p->from.u.dval, 8);
sprint(literal, "$f64.%016llux", (uvlong)i64);
s = linklookup(ctxt, literal, 0);
if(s->type == 0) {
s->type = SRODATA;
adduint64(ctxt, s, i64);
s->reachable = 0;
}
p->from.type = D_OREG;
p->from.sym = s;
p->from.name = D_EXTERN;
p->from.offset = 0;
}
break;
}
if(ctxt->flag_shared) {
// Shared libraries use R_ARM_TLS_IE32 instead of
// R_ARM_TLS_LE32, replacing the link time constant TLS offset in
// runtime.tlsgm with an address to a GOT entry containing the
// offset. Rewrite $runtime.tlsgm(SB) to runtime.tlsgm(SB) to
// compensate.
if(ctxt->gmsym == nil)
ctxt->gmsym = linklookup(ctxt, "runtime.tlsgm", 0);
if(p->from.type == D_CONST && p->from.name == D_EXTERN && p->from.sym == ctxt->gmsym)
p->from.type = D_OREG;
if(p->to.type == D_CONST && p->to.name == D_EXTERN && p->to.sym == ctxt->gmsym)
p->to.type = D_OREG;
}
}
static Prog*
prg(void)
{
Prog *p;
p = emallocz(sizeof(*p));
*p = zprg;
return p;
}
static Prog* stacksplit(Link*, Prog*, int32, int);
static void initdiv(Link*);
static void softfloat(Link*, LSym*);
// Prog.mark
enum
{
FOLL = 1<<0,
LABEL = 1<<1,
LEAF = 1<<2,
};
static void
linkcase(Prog *casep)
{
Prog *p;
for(p = casep; p != nil; p = p->link){
if(p->as == ABCASE) {
for(; p != nil && p->as == ABCASE; p = p->link)
p->pcrel = casep;
break;
}
}
}
static void
nocache(Prog *p)
{
p->optab = 0;
p->from.class = 0;
p->to.class = 0;
}
static void
addstacksplit(Link *ctxt, LSym *cursym)
{
Prog *p, *pl, *q, *q1, *q2;
int o;
int32 autosize, autoffset;
autosize = 0;
if(ctxt->symmorestack[0] == nil) {
ctxt->symmorestack[0] = linklookup(ctxt, "runtime.morestack", 0);
ctxt->symmorestack[1] = linklookup(ctxt, "runtime.morestack_noctxt", 0);
}
q = nil;
ctxt->cursym = cursym;
if(cursym->text == nil || cursym->text->link == nil)
return;
softfloat(ctxt, cursym);
p = cursym->text;
autoffset = p->to.offset;
if(autoffset < 0)
autoffset = 0;
cursym->locals = autoffset;
cursym->args = p->to.offset2;
if(ctxt->debugzerostack) {
if(autoffset && !(p->reg&NOSPLIT)) {
// MOVW $4(R13), R1
p = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_CONST;
p->from.reg = 13;
p->from.offset = 4;
p->to.type = D_REG;
p->to.reg = 1;
// MOVW $n(R13), R2
p = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_CONST;
p->from.reg = 13;
p->from.offset = 4 + autoffset;
p->to.type = D_REG;
p->to.reg = 2;
// MOVW $0, R3
p = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_CONST;
p->from.offset = 0;
p->to.type = D_REG;
p->to.reg = 3;
// L:
// MOVW.nil R3, 0(R1) +4
// CMP R1, R2
// BNE L
p = pl = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_REG;
p->from.reg = 3;
p->to.type = D_OREG;
p->to.reg = 1;
p->to.offset = 4;
p->scond |= C_PBIT;
p = appendp(ctxt, p);
p->as = ACMP;
p->from.type = D_REG;
p->from.reg = 1;
p->reg = 2;
p = appendp(ctxt, p);
p->as = ABNE;
p->to.type = D_BRANCH;
p->pcond = pl;
}
}
/*
* find leaf subroutines
* strip NOPs
* expand RET
* expand BECOME pseudo
*/
for(p = cursym->text; p != nil; p = p->link) {
switch(p->as) {
case ACASE:
if(ctxt->flag_shared)
linkcase(p);
break;
case ATEXT:
p->mark |= LEAF;
break;
case ARET:
break;
case ADIV:
case ADIVU:
case AMOD:
case AMODU:
q = p;
if(ctxt->sym_div == nil)
initdiv(ctxt);
cursym->text->mark &= ~LEAF;
continue;
case ANOP:
q1 = p->link;
q->link = q1; /* q is non-nop */
if(q1 != nil)
q1->mark |= p->mark;
continue;
case ABL:
case ABX:
case ADUFFZERO:
case ADUFFCOPY:
cursym->text->mark &= ~LEAF;
case ABCASE:
case AB:
case ABEQ:
case ABNE:
case ABCS:
case ABHS:
case ABCC:
case ABLO:
case ABMI:
case ABPL:
case ABVS:
case ABVC:
case ABHI:
case ABLS:
case ABGE:
case ABLT:
case ABGT:
case ABLE:
q1 = p->pcond;
if(q1 != nil) {
while(q1->as == ANOP) {
q1 = q1->link;
p->pcond = q1;
}
}
break;
}
q = p;
}
for(p = cursym->text; p != nil; p = p->link) {
o = p->as;
switch(o) {
case ATEXT:
autosize = p->to.offset + 4;
if(autosize <= 4)
if(cursym->text->mark & LEAF) {
p->to.offset = -4;
autosize = 0;
}
if(!autosize && !(cursym->text->mark & LEAF)) {
if(ctxt->debugvlog) {
Bprint(ctxt->bso, "save suppressed in: %s\n",
cursym->name);
Bflush(ctxt->bso);
}
cursym->text->mark |= LEAF;
}
if(cursym->text->mark & LEAF) {
cursym->leaf = 1;
if(!autosize)
break;
}
if(!(p->reg & NOSPLIT))
p = stacksplit(ctxt, p, autosize, !(cursym->text->reg&NEEDCTXT)); // emit split check
// MOVW.W R14,$-autosize(SP)
p = appendp(ctxt, 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;
if(cursym->text->reg & WRAPPER) {
// g->panicwrap += autosize;
// MOVW panicwrap_offset(g), R3
// ADD $autosize, R3
// MOVW R3 panicwrap_offset(g)
p = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_OREG;
p->from.reg = REGG;
p->from.offset = 2*ctxt->arch->ptrsize;
p->to.type = D_REG;
p->to.reg = 3;
p = appendp(ctxt, p);
p->as = AADD;
p->from.type = D_CONST;
p->from.offset = autosize;
p->to.type = D_REG;
p->to.reg = 3;
p = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_REG;
p->from.reg = 3;
p->to.type = D_OREG;
p->to.reg = REGG;
p->to.offset = 2*ctxt->arch->ptrsize;
}
break;
case ARET:
nocache(p);
if(cursym->text->mark & LEAF) {
if(!autosize) {
p->as = AB;
p->from = zprg.from;
if(p->to.sym) { // retjmp
p->to.type = D_BRANCH;
} else {
p->to.type = D_OREG;
p->to.offset = 0;
p->to.reg = REGLINK;
}
break;
}
}
if(cursym->text->reg & WRAPPER) {
int scond;
// Preserve original RET's cond, to allow RET.EQ
// in the implementation of reflect.call.
scond = p->scond;
p->scond = C_SCOND_NONE;
// g->panicwrap -= autosize;
// MOVW panicwrap_offset(g), R3
// SUB $autosize, R3
// MOVW R3 panicwrap_offset(g)
p->as = AMOVW;
p->from.type = D_OREG;
p->from.reg = REGG;
p->from.offset = 2*ctxt->arch->ptrsize;
p->to.type = D_REG;
p->to.reg = 3;
p = appendp(ctxt, p);
p->as = ASUB;
p->from.type = D_CONST;
p->from.offset = autosize;
p->to.type = D_REG;
p->to.reg = 3;
p = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_REG;
p->from.reg = 3;
p->to.type = D_OREG;
p->to.reg = REGG;
p->to.offset = 2*ctxt->arch->ptrsize;
p = appendp(ctxt, p);
p->scond = scond;
}
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.
if(p->to.sym) { // retjmp
p->to.reg = REGLINK;
q2 = appendp(ctxt, p);
q2->as = AB;
q2->to.type = D_BRANCH;
q2->to.sym = p->to.sym;
p->to.sym = nil;
p = q2;
}
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(ctxt->debugdivmod)
break;
if(p->from.type != D_REG)
break;
if(p->to.type != D_REG)
break;
q1 = p;
/* MOV a,4(SP) */
p = appendp(ctxt, p);
p->as = AMOVW;
p->lineno = q1->lineno;
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(ctxt, p);
p->as = AMOVW;
p->lineno = q1->lineno;
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(ctxt, p);
p->as = ABL;
p->lineno = q1->lineno;
p->to.type = D_BRANCH;
switch(o) {
case ADIV:
p->to.sym = ctxt->sym_div;
break;
case ADIVU:
p->to.sym = ctxt->sym_divu;
break;
case AMOD:
p->to.sym = ctxt->sym_mod;
break;
case AMODU:
p->to.sym = ctxt->sym_modu;
break;
}
/* MOV REGTMP, b */
p = appendp(ctxt, p);
p->as = AMOVW;
p->lineno = q1->lineno;
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(ctxt, p);
p->as = AADD;
p->lineno = q1->lineno;
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;
/* Keep saved LR at 0(SP) after SP change. */
/* MOVW 0(SP), REGTMP; MOVW REGTMP, -8!(SP) */
/* TODO: Remove SP adjustments; see issue 6699. */
q1->as = AMOVW;
q1->from.type = D_OREG;
q1->from.reg = REGSP;
q1->from.offset = 0;
q1->reg = NREG;
q1->to.type = D_REG;
q1->to.reg = REGTMP;
/* SUB $8,SP */
q1 = appendp(ctxt, q1);
q1->as = AMOVW;
q1->from.type = D_REG;
q1->from.reg = REGTMP;
q1->reg = NREG;
q1->to.type = D_OREG;
q1->to.reg = REGSP;
q1->to.offset = -8;
q1->scond |= C_WBIT;
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
softfloat(Link *ctxt, LSym *cursym)
{
Prog *p, *next;
LSym *symsfloat;
int wasfloat;
if(ctxt->goarm > 5)
return;
symsfloat = linklookup(ctxt, "_sfloat", 0);
wasfloat = 0;
for(p = cursym->text; p != nil; p = p->link)
if(p->pcond != nil)
p->pcond->mark |= LABEL;
for(p = cursym->text; p != nil; p = p->link) {
switch(p->as) {
case AMOVW:
if(p->to.type == D_FREG || p->from.type == D_FREG)
goto soft;
goto notsoft;
case AMOVWD:
case AMOVWF:
case AMOVDW:
case AMOVFW:
case AMOVFD:
case AMOVDF:
case AMOVF:
case AMOVD:
case ACMPF:
case ACMPD:
case AADDF:
case AADDD:
case ASUBF:
case ASUBD:
case AMULF:
case AMULD:
case ADIVF:
case ADIVD:
case ASQRTF:
case ASQRTD:
case AABSF:
case AABSD:
goto soft;
default:
goto notsoft;
soft:
if (!wasfloat || (p->mark&LABEL)) {
next = ctxt->arch->prg();
*next = *p;
// BL _sfloat(SB)
*p = zprg;
p->link = next;
p->as = ABL;
p->to.type = D_BRANCH;
p->to.sym = symsfloat;
p->lineno = next->lineno;
p = next;
wasfloat = 1;
}
break;
notsoft:
wasfloat = 0;
}
}
}
static Prog*
stacksplit(Link *ctxt, Prog *p, int32 framesize, int noctxt)
{
int32 arg;
// MOVW g_stackguard(g), R1
p = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_OREG;
p->from.reg = REGG;
p->to.type = D_REG;
p->to.reg = 1;
if(framesize <= StackSmall) {
// small stack: SP < stackguard
// CMP stackguard, SP
p = appendp(ctxt, p);
p->as = ACMP;
p->from.type = D_REG;
p->from.reg = 1;
p->reg = REGSP;
} else if(framesize <= StackBig) {
// large stack: SP-framesize < stackguard-StackSmall
// MOVW $-framesize(SP), R2
// CMP stackguard, R2
p = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_CONST;
p->from.reg = REGSP;
p->from.offset = -framesize;
p->to.type = D_REG;
p->to.reg = 2;
p = appendp(ctxt, p);
p->as = ACMP;
p->from.type = D_REG;
p->from.reg = 1;
p->reg = 2;
} else {
// Such a large stack we need to protect against wraparound
// if SP is close to zero.
// SP-stackguard+StackGuard < framesize + (StackGuard-StackSmall)
// The +StackGuard on both sides is required to keep the left side positive:
// SP is allowed to be slightly below stackguard. See stack.h.
// CMP $StackPreempt, R1
// MOVW.NE $StackGuard(SP), R2
// SUB.NE R1, R2
// MOVW.NE $(framesize+(StackGuard-StackSmall)), R3
// CMP.NE R3, R2
p = appendp(ctxt, p);
p->as = ACMP;
p->from.type = D_CONST;
p->from.offset = (uint32)StackPreempt;
p->reg = 1;
p = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_CONST;
p->from.reg = REGSP;
p->from.offset = StackGuard;
p->to.type = D_REG;
p->to.reg = 2;
p->scond = C_SCOND_NE;
p = appendp(ctxt, p);
p->as = ASUB;
p->from.type = D_REG;
p->from.reg = 1;
p->to.type = D_REG;
p->to.reg = 2;
p->scond = C_SCOND_NE;
p = appendp(ctxt, p);
p->as = AMOVW;
p->from.type = D_CONST;
p->from.offset = framesize + (StackGuard - StackSmall);
p->to.type = D_REG;
p->to.reg = 3;
p->scond = C_SCOND_NE;
p = appendp(ctxt, p);
p->as = ACMP;
p->from.type = D_REG;
p->from.reg = 3;
p->reg = 2;
p->scond = C_SCOND_NE;
}
// MOVW.LS $framesize, R1
p = appendp(ctxt, p);
p->as = AMOVW;
p->scond = C_SCOND_LS;
p->from.type = D_CONST;
p->from.offset = framesize;
p->to.type = D_REG;
p->to.reg = 1;
// MOVW.LS $args, R2
p = appendp(ctxt, p);
p->as = AMOVW;
p->scond = C_SCOND_LS;
p->from.type = D_CONST;
arg = ctxt->cursym->text->to.offset2;
if(arg == 1) // special marker for known 0
arg = 0;
if(arg&3)
ctxt->diag("misaligned argument size in stack split");
p->from.offset = arg;
p->to.type = D_REG;
p->to.reg = 2;
// MOVW.LS R14, R3
p = appendp(ctxt, p);
p->as = AMOVW;
p->scond = C_SCOND_LS;
p->from.type = D_REG;
p->from.reg = REGLINK;
p->to.type = D_REG;
p->to.reg = 3;
// BL.LS runtime.morestack(SB) // modifies LR, returns with LO still asserted
p = appendp(ctxt, p);
p->as = ABL;
p->scond = C_SCOND_LS;
p->to.type = D_BRANCH;
p->to.sym = ctxt->symmorestack[noctxt];
// BLS start
p = appendp(ctxt, p);
p->as = ABLS;
p->to.type = D_BRANCH;
p->pcond = ctxt->cursym->text->link;
return p;
}
static void
initdiv(Link *ctxt)
{
if(ctxt->sym_div != nil)
return;
ctxt->sym_div = linklookup(ctxt, "_div", 0);
ctxt->sym_divu = linklookup(ctxt, "_divu", 0);
ctxt->sym_mod = linklookup(ctxt, "_mod", 0);
ctxt->sym_modu = linklookup(ctxt, "_modu", 0);
}
static void xfol(Link*, Prog*, Prog**);
static void
follow(Link *ctxt, LSym *s)
{
Prog *firstp, *lastp;
ctxt->cursym = s;
firstp = ctxt->arch->prg();
lastp = firstp;
xfol(ctxt, s->text, &lastp);
lastp->link = nil;
s->text = firstp->link;
}
static int
relinv(int a)
{
switch(a) {
case ABEQ: return ABNE;
case ABNE: return ABEQ;
case ABCS: return ABCC;
case ABHS: return ABLO;
case ABCC: return ABCS;
case ABLO: return ABHS;
case ABMI: return ABPL;
case ABPL: return ABMI;
case ABVS: return ABVC;
case ABVC: return ABVS;
case ABHI: return ABLS;
case ABLS: return ABHI;
case ABGE: return ABLT;
case ABLT: return ABGE;
case ABGT: return ABLE;
case ABLE: return ABGT;
}
sysfatal("unknown relation: %s", anames5[a]);
return 0;
}
static void
xfol(Link *ctxt, Prog *p, Prog **last)
{
Prog *q, *r;
int a, i;
loop:
if(p == nil)
return;
a = p->as;
if(a == AB) {
q = p->pcond;
if(q != nil && q->as != ATEXT) {
p->mark |= FOLL;
p = q;
if(!(p->mark & FOLL))
goto loop;
}
}
if(p->mark & FOLL) {
for(i=0,q=p; i<4; i++,q=q->link) {
if(q == *last || q == nil)
break;
a = q->as;
if(a == ANOP) {
i--;
continue;
}
if(a == AB || (a == ARET && q->scond == C_SCOND_NONE) || a == ARFE || a == AUNDEF)
goto copy;
if(q->pcond == nil || (q->pcond->mark&FOLL))
continue;
if(a != ABEQ && a != ABNE)
continue;
copy:
for(;;) {
r = ctxt->arch->prg();
*r = *p;
if(!(r->mark&FOLL))
print("can't happen 1\n");
r->mark |= FOLL;
if(p != q) {
p = p->link;
(*last)->link = r;
*last = r;
continue;
}
(*last)->link = r;
*last = r;
if(a == AB || (a == ARET && q->scond == C_SCOND_NONE) || a == ARFE || a == AUNDEF)
return;
r->as = ABNE;
if(a == ABNE)
r->as = ABEQ;
r->pcond = p->link;
r->link = p->pcond;
if(!(r->link->mark&FOLL))
xfol(ctxt, r->link, last);
if(!(r->pcond->mark&FOLL))
print("can't happen 2\n");
return;
}
}
a = AB;
q = ctxt->arch->prg();
q->as = a;
q->lineno = p->lineno;
q->to.type = D_BRANCH;
q->to.offset = p->pc;
q->pcond = p;
p = q;
}
p->mark |= FOLL;
(*last)->link = p;
*last = p;
if(a == AB || (a == ARET && p->scond == C_SCOND_NONE) || a == ARFE || a == AUNDEF){
return;
}
if(p->pcond != nil)
if(a != ABL && a != ABX && p->link != nil) {
q = brchain(ctxt, p->link);
if(a != ATEXT && a != ABCASE)
if(q != nil && (q->mark&FOLL)) {
p->as = relinv(a);
p->link = p->pcond;
p->pcond = q;
}
xfol(ctxt, p->link, last);
q = brchain(ctxt, p->pcond);
if(q == nil)
q = p->pcond;
if(q->mark&FOLL) {
p->pcond = q;
return;
}
p = q;
goto loop;
}
p = p->link;
goto loop;
}
LinkArch linkarm = {
.name = "arm",
.thechar = '5',
.addstacksplit = addstacksplit,
.assemble = span5,
.datasize = datasize,
.follow = follow,
.iscall = iscall,
.isdata = isdata,
.prg = prg,
.progedit = progedit,
.settextflag = settextflag,
.symtype = symtype,
.textflag = textflag,
.minlc = 4,
.ptrsize = 4,
.regsize = 4,
.D_ADDR = D_ADDR,
.D_AUTO = D_AUTO,
.D_BRANCH = D_BRANCH,
.D_CONST = D_CONST,
.D_EXTERN = D_EXTERN,
.D_FCONST = D_FCONST,
.D_NONE = D_NONE,
.D_PARAM = D_PARAM,
.D_SCONST = D_SCONST,
.D_STATIC = D_STATIC,
.ACALL = ABL,
.ADATA = ADATA,
.AEND = AEND,
.AFUNCDATA = AFUNCDATA,
.AGLOBL = AGLOBL,
.AJMP = AB,
.ANOP = ANOP,
.APCDATA = APCDATA,
.ARET = ARET,
.ATEXT = ATEXT,
.ATYPE = ATYPE,
.AUSEFIELD = AUSEFIELD,
};