diff options
Diffstat (limited to 'vendor/golang.org/x/tools/go/ssa/wrappers.go')
| -rw-r--r-- | vendor/golang.org/x/tools/go/ssa/wrappers.go | 294 |
1 files changed, 0 insertions, 294 deletions
diff --git a/vendor/golang.org/x/tools/go/ssa/wrappers.go b/vendor/golang.org/x/tools/go/ssa/wrappers.go deleted file mode 100644 index 701dd90..0000000 --- a/vendor/golang.org/x/tools/go/ssa/wrappers.go +++ /dev/null @@ -1,294 +0,0 @@ -// Copyright 2013 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -package ssa - -// This file defines synthesis of Functions that delegate to declared -// methods; they come in three kinds: -// -// (1) wrappers: methods that wrap declared methods, performing -// implicit pointer indirections and embedded field selections. -// -// (2) thunks: funcs that wrap declared methods. Like wrappers, -// thunks perform indirections and field selections. The thunk's -// first parameter is used as the receiver for the method call. -// -// (3) bounds: funcs that wrap declared methods. The bound's sole -// free variable, supplied by a closure, is used as the receiver -// for the method call. No indirections or field selections are -// performed since they can be done before the call. - -import ( - "fmt" - - "go/types" -) - -// -- wrappers ----------------------------------------------------------- - -// 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 -} - -// createParams creates parameters for wrapper method fn based on its -// Signature.Params, which do not include the receiver. -// start is the index of the first regular parameter to use. -// -func createParams(fn *Function, start int) { - var last *Parameter - tparams := fn.Signature.Params() - for i, n := start, tparams.Len(); i < n; i++ { - last = fn.addParamObj(tparams.At(i)) - } - if fn.Signature.Variadic() { - last.typ = types.NewSlice(last.typ) - } -} - -// -- bounds ----------------------------------------------------------- - -// makeBound returns a bound method wrapper (or "bound"), a synthetic -// function that delegates to a concrete or interface method denoted -// by obj. The resulting function has no receiver, but has one free -// variable which will be used as the method's receiver in the -// tail-call. -// -// Use MakeClosure with such a wrapper to construct a bound method -// closure. e.g.: -// -// type T int or: type T interface { meth() } -// func (t T) meth() -// var t T -// f := t.meth -// f() // calls t.meth() -// -// f is a closure of a synthetic wrapper defined as if by: -// -// f := func() { return t.meth() } -// -// Unlike makeWrapper, makeBound need perform no indirection or field -// selections because that can be done before the closure is -// constructed. -// -// EXCLUSIVE_LOCKS_ACQUIRED(meth.Prog.methodsMu) -// -func makeBound(prog *Program, obj *types.Func) *Function { - prog.methodsMu.Lock() - defer prog.methodsMu.Unlock() - fn, ok := prog.bounds[obj] - if !ok { - description := fmt.Sprintf("bound method wrapper for %s", obj) - if prog.mode&LogSource != 0 { - defer logStack("%s", description)() - } - fn = &Function{ - name: obj.Name() + "$bound", - object: obj, - Signature: changeRecv(obj.Type().(*types.Signature), nil), // drop receiver - Synthetic: description, - Prog: prog, - pos: obj.Pos(), - } - - fv := &FreeVar{name: "recv", typ: recvType(obj), parent: fn} - fn.FreeVars = []*FreeVar{fv} - fn.startBody() - createParams(fn, 0) - var c Call - - if !isInterface(recvType(obj)) { // concrete - c.Call.Value = prog.declaredFunc(obj) - c.Call.Args = []Value{fv} - } else { - c.Call.Value = fv - c.Call.Method = obj - } - for _, arg := range fn.Params { - c.Call.Args = append(c.Call.Args, arg) - } - emitTailCall(fn, &c) - fn.finishBody() - - prog.bounds[obj] = fn - } - return fn -} - -// -- thunks ----------------------------------------------------------- - -// makeThunk returns a thunk, a synthetic function that delegates to a -// concrete or interface method denoted by sel.Obj(). The resulting -// function has no receiver, but has an additional (first) regular -// parameter. -// -// Precondition: sel.Kind() == types.MethodExpr. -// -// type T int or: type T interface { meth() } -// func (t T) meth() -// f := T.meth -// var t T -// f(t) // calls t.meth() -// -// f is a synthetic wrapper defined as if by: -// -// f := func(t T) { return t.meth() } -// -// TODO(adonovan): opt: currently the stub is created even when used -// directly in a function call: C.f(i, 0). This is less efficient -// than inlining the stub. -// -// EXCLUSIVE_LOCKS_ACQUIRED(meth.Prog.methodsMu) -// -func makeThunk(prog *Program, sel *types.Selection) *Function { - if sel.Kind() != types.MethodExpr { - panic(sel) - } - - key := selectionKey{ - kind: sel.Kind(), - recv: sel.Recv(), - obj: sel.Obj(), - index: fmt.Sprint(sel.Index()), - indirect: sel.Indirect(), - } - - prog.methodsMu.Lock() - defer prog.methodsMu.Unlock() - - // Canonicalize key.recv to avoid constructing duplicate thunks. - canonRecv, ok := prog.canon.At(key.recv).(types.Type) - if !ok { - canonRecv = key.recv - prog.canon.Set(key.recv, canonRecv) - } - key.recv = canonRecv - - fn, ok := prog.thunks[key] - if !ok { - fn = makeWrapper(prog, sel) - if fn.Signature.Recv() != nil { - panic(fn) // unexpected receiver - } - prog.thunks[key] = fn - } - return fn -} - -func changeRecv(s *types.Signature, recv *types.Var) *types.Signature { - return types.NewSignature(recv, s.Params(), s.Results(), s.Variadic()) -} - -// selectionKey is like types.Selection but a usable map key. -type selectionKey struct { - kind types.SelectionKind - recv types.Type // canonicalized via Program.canon - obj types.Object - index string - indirect bool -} |