Exemple #1
0
// lookup returns the address of the named variable identified by obj
// that is local to function f or one of its enclosing functions.
// If escaping, the reference comes from a potentially escaping pointer
// expression and the referent must be heap-allocated.
//
func (f *Function) lookup(obj types.Object, escaping bool) Value {
	if v, ok := f.objects[obj]; ok {
		if alloc, ok := v.(*Alloc); ok && escaping {
			alloc.Heap = true
		}
		return v // function-local var (address)
	}

	// Definition must be in an enclosing function;
	// plumb it through intervening closures.
	if f.parent == nil {
		panic("no ssa.Value for " + obj.String())
	}
	outer := f.parent.lookup(obj, true) // escaping
	v := &FreeVar{
		name:   obj.Name(),
		typ:    outer.Type(),
		pos:    outer.Pos(),
		outer:  outer,
		parent: f,
	}
	f.objects[obj] = v
	f.FreeVars = append(f.FreeVars, v)
	return v
}
Exemple #2
0
func (f *Function) addParamObj(obj types.Object) *Parameter {
	name := obj.Name()
	if name == "" {
		name = fmt.Sprintf("arg%d", len(f.Params))
	}
	param := f.addParam(name, obj.Type(), obj.Pos())
	param.object = obj
	return param
}
Exemple #3
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// addSpilledParam declares a parameter that is pre-spilled to the
// stack; the function body will load/store the spilled location.
// Subsequent lifting will eliminate spills where possible.
//
func (f *Function) addSpilledParam(obj types.Object) {
	param := f.addParamObj(obj)
	spill := &Alloc{Comment: obj.Name()}
	spill.setType(types.NewPointer(obj.Type()))
	spill.setPos(obj.Pos())
	f.objects[obj] = spill
	f.Locals = append(f.Locals, spill)
	f.emit(spill)
	f.emit(&Store{Addr: spill, Val: param})
}
Exemple #4
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func (p *exporter) obj(obj types.Object) {
	if trace {
		p.tracef("object %s {\n", obj.Name())
		defer p.tracef("}\n")
	}

	switch obj := obj.(type) {
	case *types.Const:
		p.int(constTag)
		p.string(obj.Name())
		p.typ(obj.Type())
		p.value(obj.Val())
	case *types.TypeName:
		p.int(typeTag)
		// name is written by corresponding named type
		p.typ(obj.Type().(*types.Named))
	case *types.Var:
		p.int(varTag)
		p.string(obj.Name())
		p.typ(obj.Type())
	case *types.Func:
		p.int(funcTag)
		p.string(obj.Name())
		p.typ(obj.Type())
	default:
		panic(fmt.Sprintf("unexpected object type %T", obj))
	}
}
Exemple #5
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// memberFromObject populates package pkg with a member for the
// typechecker object obj.
//
// For objects from Go source code, syntax is the associated syntax
// tree (for funcs and vars only); it will be used during the build
// phase.
//
func memberFromObject(pkg *Package, obj types.Object, syntax ast.Node) {
	name := obj.Name()
	switch obj := obj.(type) {
	case *types.TypeName:
		pkg.Members[name] = &Type{
			object: obj,
			pkg:    pkg,
		}

	case *types.Const:
		c := &NamedConst{
			object: obj,
			Value:  NewConst(obj.Val(), obj.Type()),
			pkg:    pkg,
		}
		pkg.values[obj] = c.Value
		pkg.Members[name] = c

	case *types.Var:
		g := &Global{
			Pkg:    pkg,
			name:   name,
			object: obj,
			typ:    types.NewPointer(obj.Type()), // address
			pos:    obj.Pos(),
		}
		pkg.values[obj] = g
		pkg.Members[name] = g

	case *types.Func:
		sig := obj.Type().(*types.Signature)
		if sig.Recv() == nil && name == "init" {
			pkg.ninit++
			name = fmt.Sprintf("init#%d", pkg.ninit)
		}
		fn := &Function{
			name:      name,
			object:    obj,
			Signature: sig,
			syntax:    syntax,
			pos:       obj.Pos(),
			Pkg:       pkg,
			Prog:      pkg.Prog,
		}
		if syntax == nil {
			fn.Synthetic = "loaded from gc object file"
		}

		pkg.values[obj] = fn
		if sig.Recv() == nil {
			pkg.Members[name] = fn // package-level function
		}

	default: // (incl. *types.Package)
		panic("unexpected Object type: " + obj.String())
	}
}
Exemple #6
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// addNamedLocal creates a local variable, adds it to function f and
// returns it.  Its name and type are taken from obj.  Subsequent
// calls to f.lookup(obj) will return the same local.
//
func (f *Function) addNamedLocal(obj types.Object) *Alloc {
	l := f.addLocal(obj.Type(), obj.Pos())
	l.Comment = obj.Name()
	f.objects[obj] = l
	return l
}
Exemple #7
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// packageLevelValue returns the package-level value corresponding to
// the specified named object, which may be a package-level const
// (*Const), var (*Global) or func (*Function) of some package in
// prog.  It returns nil if the object is not found.
//
func (prog *Program) packageLevelValue(obj types.Object) Value {
	if pkg, ok := prog.packages[obj.Pkg()]; ok {
		return pkg.values[obj]
	}
	return nil
}