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// Inferno utils/6l/pass.c
// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/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.
package obj
// Code and data passes.
func Brchain(ctxt *Link, p *Prog) *Prog {
for i := 0; i < 20; i++ {
if p == nil || p.As != AJMP || p.Pcond == nil {
return p
}
p = p.Pcond
}
return nil
}
func brloop(ctxt *Link, p *Prog) *Prog {
var q *Prog
c := 0
for q = p; q != nil; q = q.Pcond {
if q.As != AJMP || q.Pcond == nil {
break
}
c++
if c >= 5000 {
return nil
}
}
return q
}
func checkaddr(ctxt *Link, p *Prog, a *Addr) {
// Check expected encoding, especially TYPE_CONST vs TYPE_ADDR.
switch a.Type {
case TYPE_NONE:
return
case TYPE_BRANCH:
if a.Reg != 0 || a.Index != 0 || a.Scale != 0 || a.Name != 0 {
break
}
return
case TYPE_TEXTSIZE:
if a.Reg != 0 || a.Index != 0 || a.Scale != 0 || a.Name != 0 {
break
}
return
//if(a->u.bits != 0)
// break;
case TYPE_MEM:
return
// TODO(rsc): After fixing SHRQ, check a->index != 0 too.
case TYPE_CONST:
if a.Name != 0 || a.Sym != nil || a.Reg != 0 {
ctxt.Diag("argument is TYPE_CONST, should be TYPE_ADDR, in %v", p)
return
}
if a.Reg != 0 || a.Scale != 0 || a.Name != 0 || a.Sym != nil || a.Val != nil {
break
}
return
case TYPE_FCONST, TYPE_SCONST:
if a.Reg != 0 || a.Index != 0 || a.Scale != 0 || a.Name != 0 || a.Offset != 0 || a.Sym != nil {
break
}
return
// TODO(rsc): After fixing PINSRQ, check a->offset != 0 too.
// TODO(rsc): After fixing SHRQ, check a->index != 0 too.
case TYPE_REG:
if a.Scale != 0 || a.Name != 0 || a.Sym != nil {
break
}
return
case TYPE_ADDR:
if a.Val != nil {
break
}
if a.Reg == 0 && a.Index == 0 && a.Scale == 0 && a.Name == 0 && a.Sym == nil {
ctxt.Diag("argument is TYPE_ADDR, should be TYPE_CONST, in %v", p)
}
return
case TYPE_SHIFT:
if a.Index != 0 || a.Scale != 0 || a.Name != 0 || a.Sym != nil || a.Val != nil {
break
}
return
case TYPE_REGREG:
if a.Index != 0 || a.Scale != 0 || a.Name != 0 || a.Sym != nil || a.Val != nil {
break
}
return
case TYPE_REGREG2:
return
case TYPE_REGLIST:
return
// Expect sym and name to be set, nothing else.
// Technically more is allowed, but this is only used for *name(SB).
case TYPE_INDIR:
if a.Reg != 0 || a.Index != 0 || a.Scale != 0 || a.Name == 0 || a.Offset != 0 || a.Sym == nil || a.Val != nil {
break
}
return
}
ctxt.Diag("invalid encoding for argument %v", p)
}
func linkpatch(ctxt *Link, sym *LSym) {
var c int32
var name string
var q *Prog
ctxt.Cursym = sym
for p := sym.Text; p != nil; p = p.Link {
checkaddr(ctxt, p, &p.From)
if p.From3 != nil {
checkaddr(ctxt, p, p.From3)
}
checkaddr(ctxt, p, &p.To)
if ctxt.Arch.Progedit != nil {
ctxt.Arch.Progedit(ctxt, p)
}
if p.To.Type != TYPE_BRANCH {
continue
}
if p.To.Val != nil {
// TODO: Remove To.Val.(*Prog) in favor of p->pcond.
p.Pcond = p.To.Val.(*Prog)
continue
}
if p.To.Sym != nil {
continue
}
c = int32(p.To.Offset)
for q = sym.Text; q != nil; {
if int64(c) == q.Pc {
break
}
if q.Forwd != nil && int64(c) >= q.Forwd.Pc {
q = q.Forwd
} else {
q = q.Link
}
}
if q == nil {
name = "<nil>"
if p.To.Sym != nil {
name = p.To.Sym.Name
}
ctxt.Diag("branch out of range (%#x)\n%v [%s]", uint32(c), p, name)
p.To.Type = TYPE_NONE
}
p.To.Val = q
p.Pcond = q
}
if ctxt.Flag_optimize {
for p := sym.Text; p != nil; p = p.Link {
if p.Pcond != nil {
p.Pcond = brloop(ctxt, p.Pcond)
if p.Pcond != nil {
if p.To.Type == TYPE_BRANCH {
p.To.Offset = p.Pcond.Pc
}
}
}
}
}
}
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