/
pass.go
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/
pass.go
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package liblink
// Inferno utils/6l/pass.c
// http://code.google.com/p/inferno-os/source/browse/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.
// Code and data passes.
func Brchain(ctxt *Link, p *Prog) *Prog {
var i int
for i = 0; i < 20; i++ {
if p == nil || p.As != ctxt.Arch.AJMP {
return p
}
p = p.Pcond
}
return nil
}
func brloop(ctxt *Link, p *Prog) *Prog {
var c int
var q *Prog
c = 0
for q = p; q != nil; q = q.Pcond {
if q.As != ctxt.Arch.AJMP {
break
}
c++
if c >= 5000 {
return nil
}
}
return q
}
func linkpatch(ctxt *Link, sym *LSym) {
var c int64
var p *Prog
var q *Prog
ctxt.Cursym = sym
for p = sym.Text; p != nil; p = p.Link {
if ctxt.Arch.Progedit != nil {
ctxt.Arch.Progedit(ctxt, p)
}
if p.To.Typ != ctxt.Arch.D_BRANCH {
continue
}
if p.To.U.Branch != nil {
// TODO: Remove to.u.branch in favor of p->pcond.
p.Pcond = p.To.U.Branch
continue
}
if p.To.Sym != nil {
continue
}
c = p.To.Offset
for q = sym.Text; q != nil; {
if c == q.Pc {
break
}
if q.Forwd != nil && c >= q.Forwd.Pc {
q = q.Forwd
} else {
q = q.Link
}
}
if q == nil {
var tmp string
if p.To.Sym != nil {
tmp = p.To.Sym.Name
} else {
tmp = "<nil>"
}
ctxt.Diag("branch out of range (%#ux)\n%P [%s]", c, p, tmp)
p.To.Typ = ctxt.Arch.D_NONE
}
p.To.U.Branch = q
p.Pcond = q
}
for p = sym.Text; p != nil; p = p.Link {
p.Mark = 0 /* initialization for follow */
if p.Pcond != nil {
p.Pcond = brloop(ctxt, p.Pcond)
if p.Pcond != nil {
if p.To.Typ == ctxt.Arch.D_BRANCH {
p.To.Offset = p.Pcond.Pc
}
}
}
}
}