func (p *exporter) field(f *types.Var) {
// anonymous fields have "" name
name := ""
if !f.Anonymous() {
name = f.Name()
}
// qualifiedName will always emit the field package for
// anonymous fields because "" is not an exported name.
p.qualifiedName(f.Pkg(), name)
p.typ(f.Type())
}
func (tr *Transformer) matchWildcard(xobj *types.Var, y ast.Expr) bool {
name := xobj.Name()
if tr.verbose {
fmt.Fprintf(os.Stderr, "%s: wildcard %s -> %s?: ",
tr.fset.Position(y.Pos()), name, astString(tr.fset, y))
}
// Check that y is assignable to the declared type of the param.
yt := tr.info.TypeOf(y)
if yt == nil {
// y has no type.
// Perhaps it is an *ast.Ellipsis in [...]T{}, or
// an *ast.KeyValueExpr in T{k: v}.
// Clearly these pseudo-expressions cannot match a
// wildcard, but it would nice if we had a way to ignore
// the difference between T{v} and T{k:v} for structs.
return false
}
if !types.AssignableTo(yt, xobj.Type()) {
if tr.verbose {
fmt.Fprintf(os.Stderr, "%s not assignable to %s\n", yt, xobj.Type())
}
return false
}
// A wildcard matches any expression.
// If it appears multiple times in the pattern, it must match
// the same expression each time.
if old, ok := tr.env[name]; ok {
// found existing binding
tr.allowWildcards = false
r := tr.matchExpr(old, y)
if tr.verbose {
fmt.Fprintf(os.Stderr, "%t secondary match, primary was %s\n",
r, astString(tr.fset, old))
}
tr.allowWildcards = true
return r
}
if tr.verbose {
fmt.Fprintf(os.Stderr, "primary match\n")
}
tr.env[name] = y // record binding
return true
}
// checkStructField checks that the field renaming will not cause
// conflicts at its declaration, or ambiguity or changes to any selection.
func (e *Export) checkStructField(from *types.Var, to string) {
// Check that the struct declaration is free of field conflicts,
// and field/method conflicts.
t := getEnclosingStruct(from)
if t != t.Underlying() {
// This struct is also a named type.
// We must check for direct (non-promoted) field/field
// and method/field conflicts.
_, indices, _ := types.LookupFieldOrMethod(t, true, e.u.pkgInfo.Pkg, to)
if len(indices) == 1 {
e.Conflicting = true
return
}
} else {
// This struct is not a named type.
// We need only check for direct (non-promoted) field/field conflicts.
T := t.Underlying().(*types.Struct)
for i := 0; i < T.NumFields(); i++ {
if prev := T.Field(i); prev.Name() == to {
e.Conflicting = true
return
}
}
}
// Renaming an anonymous field requires renaming the type too. e.g.
// print(s.T) // if we rename T to U,
// type T int // this and
// var s struct {T} // this must change too.
if from.Anonymous() {
if named, ok := from.Type().(*types.Named); ok {
e.check(named.Obj(), to)
} else if named, ok := deref(from.Type()).(*types.Named); ok {
e.check(named.Obj(), to)
}
}
// Check integrity of existing (field and method) selections.
e.checkSelections(from, to)
}
func checkVarValue(t *testing.T, prog *ssa.Program, pkg *ssa.Package, ref []ast.Node, obj *types.Var, expKind string, wantAddr bool) {
// The prefix of all assertions messages.
prefix := fmt.Sprintf("VarValue(%s @ L%d)",
obj, prog.Fset.Position(ref[0].Pos()).Line)
v, gotAddr := prog.VarValue(obj, pkg, ref)
// Kind is the concrete type of the ssa Value.
gotKind := "nil"
if v != nil {
gotKind = fmt.Sprintf("%T", v)[len("*ssa."):]
}
// fmt.Printf("%s = %v (kind %q; expect %q) wantAddr=%t gotAddr=%t\n", prefix, v, gotKind, expKind, wantAddr, gotAddr) // debugging
// Check the kinds match.
// "nil" indicates expected failure (e.g. optimized away).
if expKind != gotKind {
t.Errorf("%s concrete type == %s, want %s", prefix, gotKind, expKind)
}
// Check the types match.
// If wantAddr, the expected type is the object's address.
if v != nil {
expType := obj.Type()
if wantAddr {
expType = types.NewPointer(expType)
if !gotAddr {
t.Errorf("%s: got value, want address", prefix)
}
} else if gotAddr {
t.Errorf("%s: got address, want value", prefix)
}
if !types.Identical(v.Type(), expType) {
t.Errorf("%s.Type() == %s, want %s", prefix, v.Type(), expType)
}
}
}
func (tr *Transformer) matchWildcard(xobj *types.Var, y ast.Expr) bool {
name := xobj.Name()
if tr.verbose {
fmt.Fprintf(os.Stderr, "%s: wildcard %s -> %s?: ",
tr.fset.Position(y.Pos()), name, astString(tr.fset, y))
}
// Check that y is assignable to the declared type of the param.
if yt := tr.info.TypeOf(y); !types.AssignableTo(yt, xobj.Type()) {
if tr.verbose {
fmt.Fprintf(os.Stderr, "%s not assignable to %s\n", yt, xobj.Type())
}
return false
}
// A wildcard matches any expression.
// If it appears multiple times in the pattern, it must match
// the same expression each time.
if old, ok := tr.env[name]; ok {
// found existing binding
tr.allowWildcards = false
r := tr.matchExpr(old, y)
if tr.verbose {
fmt.Fprintf(os.Stderr, "%t secondary match, primary was %s\n",
r, astString(tr.fset, old))
}
tr.allowWildcards = true
return r
}
if tr.verbose {
fmt.Fprintf(os.Stderr, "primary match\n")
}
tr.env[name] = y // record binding
return true
}
// checkStructField checks that the field renaming will not cause
// conflicts at its declaration, or ambiguity or changes to any selection.
func (r *Unexporter) checkStructField(objsToUpdate map[types.Object]string, from *types.Var, to string) {
// Check that the struct declaration is free of field conflicts,
// and field/method conflicts.
// go/types offers no easy way to get from a field (or interface
// method) to its declaring struct (or interface), so we must
// ascend the AST.
info, path, _ := r.iprog.PathEnclosingInterval(from.Pos(), from.Pos())
// path matches this pattern:
// [Ident SelectorExpr? StarExpr? Field FieldList StructType ParenExpr* ... File]
// Ascend to FieldList.
var i int
for {
if _, ok := path[i].(*ast.FieldList); ok {
break
}
i++
}
i++
tStruct := path[i].(*ast.StructType)
i++
// Ascend past parens (unlikely).
for {
_, ok := path[i].(*ast.ParenExpr)
if !ok {
break
}
i++
}
if spec, ok := path[i].(*ast.TypeSpec); ok {
// This struct is also a named type.
// We must check for direct (non-promoted) field/field
// and method/field conflicts.
named := info.Defs[spec.Name].Type()
prev, indices, _ := types.LookupFieldOrMethod(named, true, info.Pkg, to)
if len(indices) == 1 {
r.warn(from,
r.errorf(from.Pos(), "renaming this field %q to %q",
from.Name(), to),
r.errorf(prev.Pos(), "\twould conflict with this %s",
objectKind(prev)))
return // skip checkSelections to avoid redundant errors
}
} else {
// This struct is not a named type.
// We need only check for direct (non-promoted) field/field conflicts.
t := info.Types[tStruct].Type.Underlying().(*types.Struct)
for i := 0; i < t.NumFields(); i++ {
if prev := t.Field(i); prev.Name() == to {
r.warn(from,
r.errorf(from.Pos(), "renaming this field %q to %q",
from.Name(), to),
r.errorf(prev.Pos(), "\twould conflict with this field"))
return // skip checkSelections to avoid redundant errors
}
}
}
// Renaming an anonymous field requires renaming the type too. e.g.
// print(s.T) // if we rename T to U,
// type T int // this and
// var s struct {T} // this must change too.
if from.Anonymous() {
if named, ok := from.Type().(*types.Named); ok {
r.check(objsToUpdate, named.Obj(), to)
} else if named, ok := deref(from.Type()).(*types.Named); ok {
r.check(objsToUpdate, named.Obj(), to)
}
}
// Check integrity of existing (field and method) selections.
r.checkSelections(objsToUpdate, from, to)
}
func newVar(v *types.Var) *Var {
return &Var{
Var: v,
dtype: getTypedesc(v.Type()),
}
}
// makeWrapper returns a synthetic method that delegates to the
// declared method denoted by meth.Obj(), first performing any
// necessary pointer indirections or field selections implied by meth.
//
// The resulting method's receiver type is meth.Recv().
//
// This function is versatile but quite subtle! Consider the
// following axes of variation when making changes:
// - optional receiver indirection
// - optional implicit field selections
// - meth.Obj() may denote a concrete or an interface method
// - the result may be a thunk or a wrapper.
//
// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu)
//
func makeWrapper(prog *Program, sel *types.Selection) *Function {
obj := sel.Obj().(*types.Func) // the declared function
sig := sel.Type().(*types.Signature) // type of this wrapper
var recv *types.Var // wrapper's receiver or thunk's params[0]
name := obj.Name()
var description string
var start int // first regular param
if sel.Kind() == types.MethodExpr {
name += "$thunk"
description = "thunk"
recv = sig.Params().At(0)
start = 1
} else {
description = "wrapper"
recv = sig.Recv()
}
description = fmt.Sprintf("%s for %s", description, sel.Obj())
if prog.mode&LogSource != 0 {
defer logStack("make %s to (%s)", description, recv.Type())()
}
fn := &Function{
name: name,
method: sel,
object: obj,
Signature: sig,
Synthetic: description,
Prog: prog,
pos: obj.Pos(),
}
fn.startBody()
fn.addSpilledParam(recv)
createParams(fn, start)
indices := sel.Index()
var v Value = fn.Locals[0] // spilled receiver
if isPointer(sel.Recv()) {
v = emitLoad(fn, v)
// For simple indirection wrappers, perform an informative nil-check:
// "value method (T).f called using nil *T pointer"
if len(indices) == 1 && !isPointer(recvType(obj)) {
var c Call
c.Call.Value = &Builtin{
name: "ssa:wrapnilchk",
sig: types.NewSignature(nil,
types.NewTuple(anonVar(sel.Recv()), anonVar(tString), anonVar(tString)),
types.NewTuple(anonVar(sel.Recv())), false),
}
c.Call.Args = []Value{
v,
stringConst(deref(sel.Recv()).String()),
stringConst(sel.Obj().Name()),
}
c.setType(v.Type())
v = fn.emit(&c)
}
}
// Invariant: v is a pointer, either
// value of *A receiver param, or
// address of A spilled receiver.
// We use pointer arithmetic (FieldAddr possibly followed by
// Load) in preference to value extraction (Field possibly
// preceded by Load).
v = emitImplicitSelections(fn, v, indices[:len(indices)-1])
// Invariant: v is a pointer, either
// value of implicit *C field, or
// address of implicit C field.
var c Call
if r := recvType(obj); !isInterface(r) { // concrete method
if !isPointer(r) {
v = emitLoad(fn, v)
}
c.Call.Value = prog.declaredFunc(obj)
c.Call.Args = append(c.Call.Args, v)
} else {
c.Call.Method = obj
c.Call.Value = emitLoad(fn, v)
}
for _, arg := range fn.Params[1:] {
c.Call.Args = append(c.Call.Args, arg)
}
emitTailCall(fn, &c)
fn.finishBody()
return fn
}
func newVarFrom(p *Package, v *types.Var) *Var {
return newVar(p, v.Type(), v.Name(), v.Name(), p.getDoc("", v))
}
func (p *exporter) param(v *types.Var) {
p.string(v.Name())
p.typ(v.Type())
}