diff options
Diffstat (limited to 'vendor/github.com/google/gops/internal/obj/pass.go')
| -rw-r--r-- | vendor/github.com/google/gops/internal/obj/pass.go | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/vendor/github.com/google/gops/internal/obj/pass.go b/vendor/github.com/google/gops/internal/obj/pass.go new file mode 100644 index 00000000..1d2f74b9 --- /dev/null +++ b/vendor/github.com/google/gops/internal/obj/pass.go @@ -0,0 +1,217 @@ +// 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 + } + } + } + } + } +} |