go/src/cmd/internal/obj/sym.go

// Derived from Inferno utils/6l/obj.c and utils/6l/span.c
// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/obj.c
// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/span.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

import (
	"cmd/internal/objabi"
	"fmt"
	"log"
	"math"
)

func Linknew(arch *LinkArch) *Link {
	ctxt := new(Link)
	ctxt.hash = make(map[string]*LSym)
	ctxt.funchash = make(map[string]*LSym)
	ctxt.statichash = make(map[string]*LSym)
	ctxt.Arch = arch
	ctxt.Pathname = objabi.WorkingDir()

	if err := ctxt.Headtype.Set(objabi.GOOS); err != nil {
		log.Fatalf("unknown goos %s", objabi.GOOS)
	}

	ctxt.Flag_optimize = true
	ctxt.Framepointer_enabled = objabi.Framepointer_enabled(objabi.GOOS, arch.Name)
	return ctxt
}

// LookupDerived looks up or creates the symbol with name name derived from symbol s.
// The resulting symbol will be static iff s is.
func (ctxt *Link) LookupDerived(s *LSym, name string) *LSym {
	if s.Static() {
		return ctxt.LookupStatic(name)
	}
	return ctxt.Lookup(name)
}

// LookupStatic looks up the static symbol with name name.
// If it does not exist, it creates it.
func (ctxt *Link) LookupStatic(name string) *LSym {
	s := ctxt.statichash[name]
	if s == nil {
		s = &LSym{Name: name, Attribute: AttrStatic}
		ctxt.statichash[name] = s
	}
	return s
}

// LookupABI looks up a symbol with the given ABI.
// If it does not exist, it creates it.
func (ctxt *Link) LookupABI(name string, abi ABI) *LSym {
	var hash map[string]*LSym
	switch abi {
	case ABI0:
		hash = ctxt.hash
	case ABIInternal:
		hash = ctxt.funchash
	default:
		panic("unknown ABI")
	}

	ctxt.hashmu.Lock()
	s := hash[name]
	if s == nil {
		s = &LSym{Name: name}
		s.SetABI(abi)
		hash[name] = s
	}
	ctxt.hashmu.Unlock()
	return s
}

// Lookup looks up the symbol with name name.
// If it does not exist, it creates it.
func (ctxt *Link) Lookup(name string) *LSym {
	return ctxt.LookupInit(name, nil)
}

// LookupInit looks up the symbol with name name.
// If it does not exist, it creates it and
// passes it to init for one-time initialization.
func (ctxt *Link) LookupInit(name string, init func(s *LSym)) *LSym {
	ctxt.hashmu.Lock()
	s := ctxt.hash[name]
	if s == nil {
		s = &LSym{Name: name}
		ctxt.hash[name] = s
		if init != nil {
			init(s)
		}
	}
	ctxt.hashmu.Unlock()
	return s
}

func (ctxt *Link) Float32Sym(f float32) *LSym {
	i := math.Float32bits(f)
	name := fmt.Sprintf("$f32.%08x", i)
	return ctxt.LookupInit(name, func(s *LSym) {
		s.Size = 4
		s.Set(AttrLocal, true)
	})
}

func (ctxt *Link) Float64Sym(f float64) *LSym {
	i := math.Float64bits(f)
	name := fmt.Sprintf("$f64.%016x", i)
	return ctxt.LookupInit(name, func(s *LSym) {
		s.Size = 8
		s.Set(AttrLocal, true)
	})
}

func (ctxt *Link) Int64Sym(i int64) *LSym {
	name := fmt.Sprintf("$i64.%016x", uint64(i))
	return ctxt.LookupInit(name, func(s *LSym) {
		s.Size = 8
		s.Set(AttrLocal, true)
	})
}