mirror of
https://github.com/golang/go
synced 2024-10-03 22:21:22 -06:00
e6d3511264
This reverts commit ab0535ae3f
.
I think it will remain useful to distinguish code that must
run on a system stack from code that can run on either stack,
even if that distinction is no
longer based on the implementation language.
That is, I expect to add a //go:systemstack comment that,
in terms of the old implementation, tells the compiler,
to pretend this function was written in C.
Change-Id: I33d2ebb2f99ae12496484c6ec8ed07233d693275
Reviewed-on: https://go-review.googlesource.com/2275
Reviewed-by: Russ Cox <rsc@golang.org>
883 lines
19 KiB
C
883 lines
19 KiB
C
// Inferno utils/8l/pass.c
|
|
// http://code.google.com/p/inferno-os/source/browse/utils/8l/pass.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/8l/8.out.h"
|
|
#include "../runtime/stack.h"
|
|
|
|
static Prog zprg = {
|
|
.back = 2,
|
|
.as = AGOK,
|
|
.from = {
|
|
.type = D_NONE,
|
|
.index = D_NONE,
|
|
.scale = 1,
|
|
},
|
|
.to = {
|
|
.type = D_NONE,
|
|
.index = D_NONE,
|
|
.scale = 1,
|
|
},
|
|
};
|
|
|
|
static int
|
|
symtype(Addr *a)
|
|
{
|
|
int t;
|
|
|
|
t = a->type;
|
|
if(t == D_ADDR)
|
|
t = a->index;
|
|
return t;
|
|
}
|
|
|
|
static int
|
|
isdata(Prog *p)
|
|
{
|
|
return p->as == ADATA || p->as == AGLOBL;
|
|
}
|
|
|
|
static int
|
|
iscall(Prog *p)
|
|
{
|
|
return p->as == ACALL;
|
|
}
|
|
|
|
static int
|
|
datasize(Prog *p)
|
|
{
|
|
return p->from.scale;
|
|
}
|
|
|
|
static int
|
|
textflag(Prog *p)
|
|
{
|
|
return p->from.scale;
|
|
}
|
|
|
|
static void
|
|
settextflag(Prog *p, int f)
|
|
{
|
|
p->from.scale = f;
|
|
}
|
|
|
|
static int
|
|
canuselocaltls(Link *ctxt)
|
|
{
|
|
switch(ctxt->headtype) {
|
|
case Hlinux:
|
|
case Hnacl:
|
|
case Hplan9:
|
|
case Hwindows:
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
static void
|
|
progedit(Link *ctxt, Prog *p)
|
|
{
|
|
char literal[64];
|
|
LSym *s;
|
|
Prog *q;
|
|
|
|
// See obj6.c for discussion of TLS.
|
|
if(canuselocaltls(ctxt)) {
|
|
// Reduce TLS initial exec model to TLS local exec model.
|
|
// Sequences like
|
|
// MOVL TLS, BX
|
|
// ... off(BX)(TLS*1) ...
|
|
// become
|
|
// NOP
|
|
// ... off(TLS) ...
|
|
if(p->as == AMOVL && p->from.type == D_TLS && D_AX <= p->to.type && p->to.type <= D_DI) {
|
|
p->as = ANOP;
|
|
p->from.type = D_NONE;
|
|
p->to.type = D_NONE;
|
|
}
|
|
if(p->from.index == D_TLS && D_INDIR+D_AX <= p->from.type && p->from.type <= D_INDIR+D_DI) {
|
|
p->from.type = D_INDIR+D_TLS;
|
|
p->from.scale = 0;
|
|
p->from.index = D_NONE;
|
|
}
|
|
if(p->to.index == D_TLS && D_INDIR+D_AX <= p->to.type && p->to.type <= D_INDIR+D_DI) {
|
|
p->to.type = D_INDIR+D_TLS;
|
|
p->to.scale = 0;
|
|
p->to.index = D_NONE;
|
|
}
|
|
} else {
|
|
// As a courtesy to the C compilers, rewrite TLS local exec load as TLS initial exec load.
|
|
// The instruction
|
|
// MOVL off(TLS), BX
|
|
// becomes the sequence
|
|
// MOVL TLS, BX
|
|
// MOVL off(BX)(TLS*1), BX
|
|
// This allows the C compilers to emit references to m and g using the direct off(TLS) form.
|
|
if(p->as == AMOVL && p->from.type == D_INDIR+D_TLS && D_AX <= p->to.type && p->to.type <= D_DI) {
|
|
q = appendp(ctxt, p);
|
|
q->as = p->as;
|
|
q->from = p->from;
|
|
q->from.type = D_INDIR + p->to.type;
|
|
q->from.index = D_TLS;
|
|
q->from.scale = 2; // TODO: use 1
|
|
q->to = p->to;
|
|
p->from.type = D_TLS;
|
|
p->from.index = D_NONE;
|
|
p->from.offset = 0;
|
|
}
|
|
}
|
|
|
|
// TODO: Remove.
|
|
if(ctxt->headtype == Hplan9) {
|
|
if(p->from.scale == 1 && p->from.index == D_TLS)
|
|
p->from.scale = 2;
|
|
if(p->to.scale == 1 && p->to.index == D_TLS)
|
|
p->to.scale = 2;
|
|
}
|
|
|
|
// Rewrite CALL/JMP/RET to symbol as D_BRANCH.
|
|
switch(p->as) {
|
|
case ACALL:
|
|
case AJMP:
|
|
case ARET:
|
|
if((p->to.type == D_EXTERN || p->to.type == D_STATIC) && p->to.sym != nil)
|
|
p->to.type = D_BRANCH;
|
|
break;
|
|
}
|
|
|
|
// Rewrite float constants to values stored in memory.
|
|
switch(p->as) {
|
|
case AFMOVF:
|
|
case AFADDF:
|
|
case AFSUBF:
|
|
case AFSUBRF:
|
|
case AFMULF:
|
|
case AFDIVF:
|
|
case AFDIVRF:
|
|
case AFCOMF:
|
|
case AFCOMFP:
|
|
case AMOVSS:
|
|
case AADDSS:
|
|
case ASUBSS:
|
|
case AMULSS:
|
|
case ADIVSS:
|
|
case ACOMISS:
|
|
case AUCOMISS:
|
|
if(p->from.type == D_FCONST) {
|
|
int32 i32;
|
|
float32 f32;
|
|
f32 = p->from.u.dval;
|
|
memmove(&i32, &f32, 4);
|
|
sprint(literal, "$f32.%08ux", (uint32)i32);
|
|
s = linklookup(ctxt, literal, 0);
|
|
if(s->type == 0) {
|
|
s->type = SRODATA;
|
|
adduint32(ctxt, s, i32);
|
|
s->reachable = 0;
|
|
}
|
|
p->from.type = D_EXTERN;
|
|
p->from.sym = s;
|
|
p->from.offset = 0;
|
|
}
|
|
break;
|
|
|
|
case AFMOVD:
|
|
case AFADDD:
|
|
case AFSUBD:
|
|
case AFSUBRD:
|
|
case AFMULD:
|
|
case AFDIVD:
|
|
case AFDIVRD:
|
|
case AFCOMD:
|
|
case AFCOMDP:
|
|
case AMOVSD:
|
|
case AADDSD:
|
|
case ASUBSD:
|
|
case AMULSD:
|
|
case ADIVSD:
|
|
case ACOMISD:
|
|
case AUCOMISD:
|
|
if(p->from.type == D_FCONST) {
|
|
int64 i64;
|
|
memmove(&i64, &p->from.u.dval, 8);
|
|
sprint(literal, "$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_EXTERN;
|
|
p->from.sym = s;
|
|
p->from.offset = 0;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
static Prog*
|
|
prg(void)
|
|
{
|
|
Prog *p;
|
|
|
|
p = emallocz(sizeof(*p));
|
|
*p = zprg;
|
|
return p;
|
|
}
|
|
|
|
static Prog* load_g_cx(Link*, Prog*);
|
|
static Prog* stacksplit(Link*, Prog*, int32, int, Prog**);
|
|
|
|
static void
|
|
addstacksplit(Link *ctxt, LSym *cursym)
|
|
{
|
|
Prog *p, *q, *p1, *p2;
|
|
int32 autoffset, deltasp;
|
|
int a;
|
|
|
|
if(ctxt->symmorestack[0] == nil) {
|
|
ctxt->symmorestack[0] = linklookup(ctxt, "runtime.morestack", 0);
|
|
ctxt->symmorestack[1] = linklookup(ctxt, "runtime.morestack_noctxt", 0);
|
|
}
|
|
|
|
if(ctxt->headtype == Hplan9 && ctxt->plan9privates == nil)
|
|
ctxt->plan9privates = linklookup(ctxt, "_privates", 0);
|
|
|
|
ctxt->cursym = cursym;
|
|
|
|
if(cursym->text == nil || cursym->text->link == nil)
|
|
return;
|
|
|
|
p = cursym->text;
|
|
autoffset = p->to.offset;
|
|
if(autoffset < 0)
|
|
autoffset = 0;
|
|
|
|
cursym->locals = autoffset;
|
|
cursym->args = p->to.offset2;
|
|
|
|
q = nil;
|
|
|
|
if(!(p->from.scale & NOSPLIT) || (p->from.scale & WRAPPER)) {
|
|
p = appendp(ctxt, p);
|
|
p = load_g_cx(ctxt, p); // load g into CX
|
|
}
|
|
if(!(cursym->text->from.scale & NOSPLIT))
|
|
p = stacksplit(ctxt, p, autoffset, !(cursym->text->from.scale&NEEDCTXT), &q); // emit split check
|
|
|
|
if(autoffset) {
|
|
p = appendp(ctxt, p);
|
|
p->as = AADJSP;
|
|
p->from.type = D_CONST;
|
|
p->from.offset = autoffset;
|
|
p->spadj = autoffset;
|
|
} else {
|
|
// zero-byte stack adjustment.
|
|
// Insert a fake non-zero adjustment so that stkcheck can
|
|
// recognize the end of the stack-splitting prolog.
|
|
p = appendp(ctxt, p);
|
|
p->as = ANOP;
|
|
p->spadj = -ctxt->arch->ptrsize;
|
|
p = appendp(ctxt, p);
|
|
p->as = ANOP;
|
|
p->spadj = ctxt->arch->ptrsize;
|
|
}
|
|
if(q != nil)
|
|
q->pcond = p;
|
|
deltasp = autoffset;
|
|
|
|
if(cursym->text->from.scale & WRAPPER) {
|
|
// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
|
|
//
|
|
// MOVL g_panic(CX), BX
|
|
// TESTL BX, BX
|
|
// JEQ end
|
|
// LEAL (autoffset+4)(SP), DI
|
|
// CMPL panic_argp(BX), DI
|
|
// JNE end
|
|
// MOVL SP, panic_argp(BX)
|
|
// end:
|
|
// NOP
|
|
//
|
|
// The NOP is needed to give the jumps somewhere to land.
|
|
// It is a liblink NOP, not an x86 NOP: it encodes to 0 instruction bytes.
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AMOVL;
|
|
p->from.type = D_INDIR+D_CX;
|
|
p->from.offset = 4*ctxt->arch->ptrsize; // G.panic
|
|
p->to.type = D_BX;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ATESTL;
|
|
p->from.type = D_BX;
|
|
p->to.type = D_BX;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AJEQ;
|
|
p->to.type = D_BRANCH;
|
|
p1 = p;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ALEAL;
|
|
p->from.type = D_INDIR+D_SP;
|
|
p->from.offset = autoffset+4;
|
|
p->to.type = D_DI;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ACMPL;
|
|
p->from.type = D_INDIR+D_BX;
|
|
p->from.offset = 0; // Panic.argp
|
|
p->to.type = D_DI;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AJNE;
|
|
p->to.type = D_BRANCH;
|
|
p2 = p;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AMOVL;
|
|
p->from.type = D_SP;
|
|
p->to.type = D_INDIR+D_BX;
|
|
p->to.offset = 0; // Panic.argp
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ANOP;
|
|
p1->pcond = p;
|
|
p2->pcond = p;
|
|
}
|
|
|
|
if(ctxt->debugzerostack && autoffset && !(cursym->text->from.scale&NOSPLIT)) {
|
|
// 8l -Z means zero the stack frame on entry.
|
|
// This slows down function calls but can help avoid
|
|
// false positives in garbage collection.
|
|
p = appendp(ctxt, p);
|
|
p->as = AMOVL;
|
|
p->from.type = D_SP;
|
|
p->to.type = D_DI;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AMOVL;
|
|
p->from.type = D_CONST;
|
|
p->from.offset = autoffset/4;
|
|
p->to.type = D_CX;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AMOVL;
|
|
p->from.type = D_CONST;
|
|
p->from.offset = 0;
|
|
p->to.type = D_AX;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AREP;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ASTOSL;
|
|
}
|
|
|
|
for(; p != nil; p = p->link) {
|
|
a = p->from.type;
|
|
if(a == D_AUTO)
|
|
p->from.offset += deltasp;
|
|
if(a == D_PARAM)
|
|
p->from.offset += deltasp + 4;
|
|
a = p->to.type;
|
|
if(a == D_AUTO)
|
|
p->to.offset += deltasp;
|
|
if(a == D_PARAM)
|
|
p->to.offset += deltasp + 4;
|
|
|
|
switch(p->as) {
|
|
default:
|
|
continue;
|
|
case APUSHL:
|
|
case APUSHFL:
|
|
deltasp += 4;
|
|
p->spadj = 4;
|
|
continue;
|
|
case APUSHW:
|
|
case APUSHFW:
|
|
deltasp += 2;
|
|
p->spadj = 2;
|
|
continue;
|
|
case APOPL:
|
|
case APOPFL:
|
|
deltasp -= 4;
|
|
p->spadj = -4;
|
|
continue;
|
|
case APOPW:
|
|
case APOPFW:
|
|
deltasp -= 2;
|
|
p->spadj = -2;
|
|
continue;
|
|
case ARET:
|
|
break;
|
|
}
|
|
|
|
if(autoffset != deltasp)
|
|
ctxt->diag("unbalanced PUSH/POP");
|
|
|
|
if(autoffset) {
|
|
p->as = AADJSP;
|
|
p->from.type = D_CONST;
|
|
p->from.offset = -autoffset;
|
|
p->spadj = -autoffset;
|
|
p = appendp(ctxt, p);
|
|
p->as = ARET;
|
|
// If there are instructions following
|
|
// this ARET, they come from a branch
|
|
// with the same stackframe, so undo
|
|
// the cleanup.
|
|
p->spadj = +autoffset;
|
|
}
|
|
if(p->to.sym) // retjmp
|
|
p->as = AJMP;
|
|
}
|
|
}
|
|
|
|
// Append code to p to load g into cx.
|
|
// Overwrites p with the first instruction (no first appendp).
|
|
// Overwriting p is unusual but it lets use this in both the
|
|
// prologue (caller must call appendp first) and in the epilogue.
|
|
// Returns last new instruction.
|
|
static Prog*
|
|
load_g_cx(Link *ctxt, Prog *p)
|
|
{
|
|
Prog *next;
|
|
|
|
p->as = AMOVL;
|
|
p->from.type = D_INDIR+D_TLS;
|
|
p->from.offset = 0;
|
|
p->to.type = D_CX;
|
|
|
|
next = p->link;
|
|
progedit(ctxt, p);
|
|
while(p->link != next)
|
|
p = p->link;
|
|
|
|
if(p->from.index == D_TLS)
|
|
p->from.scale = 2;
|
|
|
|
return p;
|
|
}
|
|
|
|
// Append code to p to check for stack split.
|
|
// Appends to (does not overwrite) p.
|
|
// Assumes g is in CX.
|
|
// Returns last new instruction.
|
|
// On return, *jmpok is the instruction that should jump
|
|
// to the stack frame allocation if no split is needed.
|
|
static Prog*
|
|
stacksplit(Link *ctxt, Prog *p, int32 framesize, int noctxt, Prog **jmpok)
|
|
{
|
|
Prog *q, *q1;
|
|
|
|
if(ctxt->debugstack) {
|
|
// 8l -K means check not only for stack
|
|
// overflow but stack underflow.
|
|
// On underflow, INT 3 (breakpoint).
|
|
// Underflow itself is rare but this also
|
|
// catches out-of-sync stack guard info.
|
|
p = appendp(ctxt, p);
|
|
p->as = ACMPL;
|
|
p->from.type = D_INDIR+D_CX;
|
|
p->from.offset = 4;
|
|
p->to.type = D_SP;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AJCC;
|
|
p->to.type = D_BRANCH;
|
|
p->to.offset = 4;
|
|
q1 = p;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AINT;
|
|
p->from.type = D_CONST;
|
|
p->from.offset = 3;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ANOP;
|
|
q1->pcond = p;
|
|
}
|
|
q1 = nil;
|
|
|
|
if(framesize <= StackSmall) {
|
|
// small stack: SP <= stackguard
|
|
// CMPL SP, stackguard
|
|
p = appendp(ctxt, p);
|
|
p->as = ACMPL;
|
|
p->from.type = D_SP;
|
|
p->to.type = D_INDIR+D_CX;
|
|
p->to.offset = 2*ctxt->arch->ptrsize; // G.stackguard0
|
|
if(ctxt->cursym->cfunc)
|
|
p->to.offset = 3*ctxt->arch->ptrsize; // G.stackguard1
|
|
} else if(framesize <= StackBig) {
|
|
// large stack: SP-framesize <= stackguard-StackSmall
|
|
// LEAL -(framesize-StackSmall)(SP), AX
|
|
// CMPL AX, stackguard
|
|
p = appendp(ctxt, p);
|
|
p->as = ALEAL;
|
|
p->from.type = D_INDIR+D_SP;
|
|
p->from.offset = -(framesize-StackSmall);
|
|
p->to.type = D_AX;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ACMPL;
|
|
p->from.type = D_AX;
|
|
p->to.type = D_INDIR+D_CX;
|
|
p->to.offset = 2*ctxt->arch->ptrsize; // G.stackguard0
|
|
if(ctxt->cursym->cfunc)
|
|
p->to.offset = 3*ctxt->arch->ptrsize; // G.stackguard1
|
|
} 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.
|
|
//
|
|
// Preemption sets stackguard to StackPreempt, a very large value.
|
|
// That breaks the math above, so we have to check for that explicitly.
|
|
// MOVL stackguard, CX
|
|
// CMPL CX, $StackPreempt
|
|
// JEQ label-of-call-to-morestack
|
|
// LEAL StackGuard(SP), AX
|
|
// SUBL stackguard, AX
|
|
// CMPL AX, $(framesize+(StackGuard-StackSmall))
|
|
p = appendp(ctxt, p);
|
|
p->as = AMOVL;
|
|
p->from.type = D_INDIR+D_CX;
|
|
p->from.offset = 0;
|
|
p->from.offset = 2*ctxt->arch->ptrsize; // G.stackguard0
|
|
if(ctxt->cursym->cfunc)
|
|
p->from.offset = 3*ctxt->arch->ptrsize; // G.stackguard1
|
|
p->to.type = D_SI;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ACMPL;
|
|
p->from.type = D_SI;
|
|
p->to.type = D_CONST;
|
|
p->to.offset = (uint32)StackPreempt;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AJEQ;
|
|
p->to.type = D_BRANCH;
|
|
q1 = p;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ALEAL;
|
|
p->from.type = D_INDIR+D_SP;
|
|
p->from.offset = StackGuard;
|
|
p->to.type = D_AX;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ASUBL;
|
|
p->from.type = D_SI;
|
|
p->from.offset = 0;
|
|
p->to.type = D_AX;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ACMPL;
|
|
p->from.type = D_AX;
|
|
p->to.type = D_CONST;
|
|
p->to.offset = framesize+(StackGuard-StackSmall);
|
|
}
|
|
|
|
// common
|
|
p = appendp(ctxt, p);
|
|
p->as = AJHI;
|
|
p->to.type = D_BRANCH;
|
|
p->to.offset = 4;
|
|
q = p;
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = ACALL;
|
|
p->to.type = D_BRANCH;
|
|
if(ctxt->cursym->cfunc)
|
|
p->to.sym = linklookup(ctxt, "runtime.morestackc", 0);
|
|
else
|
|
p->to.sym = ctxt->symmorestack[noctxt];
|
|
|
|
p = appendp(ctxt, p);
|
|
p->as = AJMP;
|
|
p->to.type = D_BRANCH;
|
|
p->pcond = ctxt->cursym->text->link;
|
|
|
|
if(q != nil)
|
|
q->pcond = p->link;
|
|
if(q1 != nil)
|
|
q1->pcond = q->link;
|
|
|
|
*jmpok = q;
|
|
return p;
|
|
}
|
|
|
|
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
|
|
nofollow(int a)
|
|
{
|
|
switch(a) {
|
|
case AJMP:
|
|
case ARET:
|
|
case AIRETL:
|
|
case AIRETW:
|
|
case AUNDEF:
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
pushpop(int a)
|
|
{
|
|
switch(a) {
|
|
case APUSHL:
|
|
case APUSHFL:
|
|
case APUSHW:
|
|
case APUSHFW:
|
|
case APOPL:
|
|
case APOPFL:
|
|
case APOPW:
|
|
case APOPFW:
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
relinv(int a)
|
|
{
|
|
|
|
switch(a) {
|
|
case AJEQ: return AJNE;
|
|
case AJNE: return AJEQ;
|
|
case AJLE: return AJGT;
|
|
case AJLS: return AJHI;
|
|
case AJLT: return AJGE;
|
|
case AJMI: return AJPL;
|
|
case AJGE: return AJLT;
|
|
case AJPL: return AJMI;
|
|
case AJGT: return AJLE;
|
|
case AJHI: return AJLS;
|
|
case AJCS: return AJCC;
|
|
case AJCC: return AJCS;
|
|
case AJPS: return AJPC;
|
|
case AJPC: return AJPS;
|
|
case AJOS: return AJOC;
|
|
case AJOC: return AJOS;
|
|
}
|
|
sysfatal("unknown relation: %s", anames8[a]);
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
xfol(Link *ctxt, Prog *p, Prog **last)
|
|
{
|
|
Prog *q;
|
|
int i;
|
|
int a;
|
|
|
|
loop:
|
|
if(p == nil)
|
|
return;
|
|
if(p->as == AJMP)
|
|
if((q = p->pcond) != nil && q->as != ATEXT) {
|
|
/* mark instruction as done and continue layout at target of jump */
|
|
p->mark = 1;
|
|
p = q;
|
|
if(p->mark == 0)
|
|
goto loop;
|
|
}
|
|
if(p->mark) {
|
|
/*
|
|
* p goes here, but already used it elsewhere.
|
|
* copy up to 4 instructions or else branch to other copy.
|
|
*/
|
|
for(i=0,q=p; i<4; i++,q=q->link) {
|
|
if(q == nil)
|
|
break;
|
|
if(q == *last)
|
|
break;
|
|
a = q->as;
|
|
if(a == ANOP) {
|
|
i--;
|
|
continue;
|
|
}
|
|
if(nofollow(a) || pushpop(a))
|
|
break; // NOTE(rsc): arm does goto copy
|
|
if(q->pcond == nil || q->pcond->mark)
|
|
continue;
|
|
if(a == ACALL || a == ALOOP)
|
|
continue;
|
|
for(;;) {
|
|
if(p->as == ANOP) {
|
|
p = p->link;
|
|
continue;
|
|
}
|
|
q = copyp(ctxt, p);
|
|
p = p->link;
|
|
q->mark = 1;
|
|
(*last)->link = q;
|
|
*last = q;
|
|
if(q->as != a || q->pcond == nil || q->pcond->mark)
|
|
continue;
|
|
|
|
q->as = relinv(q->as);
|
|
p = q->pcond;
|
|
q->pcond = q->link;
|
|
q->link = p;
|
|
xfol(ctxt, q->link, last);
|
|
p = q->link;
|
|
if(p->mark)
|
|
return;
|
|
goto loop;
|
|
}
|
|
} /* */
|
|
q = ctxt->arch->prg();
|
|
q->as = AJMP;
|
|
q->lineno = p->lineno;
|
|
q->to.type = D_BRANCH;
|
|
q->to.offset = p->pc;
|
|
q->pcond = p;
|
|
p = q;
|
|
}
|
|
|
|
/* emit p */
|
|
p->mark = 1;
|
|
(*last)->link = p;
|
|
*last = p;
|
|
a = p->as;
|
|
|
|
/* continue loop with what comes after p */
|
|
if(nofollow(a))
|
|
return;
|
|
if(p->pcond != nil && a != ACALL) {
|
|
/*
|
|
* some kind of conditional branch.
|
|
* recurse to follow one path.
|
|
* continue loop on the other.
|
|
*/
|
|
if((q = brchain(ctxt, p->pcond)) != nil)
|
|
p->pcond = q;
|
|
if((q = brchain(ctxt, p->link)) != nil)
|
|
p->link = q;
|
|
if(p->from.type == D_CONST) {
|
|
if(p->from.offset == 1) {
|
|
/*
|
|
* expect conditional jump to be taken.
|
|
* rewrite so that's the fall-through case.
|
|
*/
|
|
p->as = relinv(a);
|
|
q = p->link;
|
|
p->link = p->pcond;
|
|
p->pcond = q;
|
|
}
|
|
} else {
|
|
q = p->link;
|
|
if(q->mark)
|
|
if(a != ALOOP) {
|
|
p->as = relinv(a);
|
|
p->link = p->pcond;
|
|
p->pcond = q;
|
|
}
|
|
}
|
|
xfol(ctxt, p->link, last);
|
|
if(p->pcond->mark)
|
|
return;
|
|
p = p->pcond;
|
|
goto loop;
|
|
}
|
|
p = p->link;
|
|
goto loop;
|
|
}
|
|
|
|
LinkArch link386 = {
|
|
.name = "386",
|
|
.thechar = '8',
|
|
.endian = LittleEndian,
|
|
|
|
.addstacksplit = addstacksplit,
|
|
.assemble = span8,
|
|
.datasize = datasize,
|
|
.follow = follow,
|
|
.iscall = iscall,
|
|
.isdata = isdata,
|
|
.prg = prg,
|
|
.progedit = progedit,
|
|
.settextflag = settextflag,
|
|
.symtype = symtype,
|
|
.textflag = textflag,
|
|
|
|
.minlc = 1,
|
|
.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 = ACALL,
|
|
.ADATA = ADATA,
|
|
.AEND = AEND,
|
|
.AFUNCDATA = AFUNCDATA,
|
|
.AGLOBL = AGLOBL,
|
|
.AJMP = AJMP,
|
|
.ANOP = ANOP,
|
|
.APCDATA = APCDATA,
|
|
.ARET = ARET,
|
|
.ATEXT = ATEXT,
|
|
.ATYPE = ATYPE,
|
|
.AUSEFIELD = AUSEFIELD,
|
|
};
|