mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-12-27 07:20:24 +00:00
124 lines
2.9 KiB
Go
124 lines
2.9 KiB
Go
// 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
|
|
|
|
// lvalues are the union of addressable expressions and map-index
|
|
// expressions.
|
|
|
|
import (
|
|
"go/ast"
|
|
"go/token"
|
|
"go/types"
|
|
)
|
|
|
|
// An lvalue represents an assignable location that may appear on the
|
|
// left-hand side of an assignment. This is a generalization of a
|
|
// pointer to permit updates to elements of maps.
|
|
//
|
|
type lvalue interface {
|
|
store(fn *Function, v Value) // stores v into the location
|
|
load(fn *Function) Value // loads the contents of the location
|
|
address(fn *Function) Value // address of the location
|
|
typ() types.Type // returns the type of the location
|
|
}
|
|
|
|
// An address is an lvalue represented by a true pointer.
|
|
type address struct {
|
|
addr Value
|
|
pos token.Pos // source position
|
|
expr ast.Expr // source syntax of the value (not address) [debug mode]
|
|
}
|
|
|
|
func (a *address) load(fn *Function) Value {
|
|
load := emitLoad(fn, a.addr)
|
|
load.pos = a.pos
|
|
return load
|
|
}
|
|
|
|
func (a *address) store(fn *Function, v Value) {
|
|
store := emitStore(fn, a.addr, v, a.pos)
|
|
if a.expr != nil {
|
|
// store.Val is v, converted for assignability.
|
|
emitDebugRef(fn, a.expr, store.Val, false)
|
|
}
|
|
}
|
|
|
|
func (a *address) address(fn *Function) Value {
|
|
if a.expr != nil {
|
|
emitDebugRef(fn, a.expr, a.addr, true)
|
|
}
|
|
return a.addr
|
|
}
|
|
|
|
func (a *address) typ() types.Type {
|
|
return deref(a.addr.Type())
|
|
}
|
|
|
|
// An element is an lvalue represented by m[k], the location of an
|
|
// element of a map or string. These locations are not addressable
|
|
// since pointers cannot be formed from them, but they do support
|
|
// load(), and in the case of maps, store().
|
|
//
|
|
type element struct {
|
|
m, k Value // map or string
|
|
t types.Type // map element type or string byte type
|
|
pos token.Pos // source position of colon ({k:v}) or lbrack (m[k]=v)
|
|
}
|
|
|
|
func (e *element) load(fn *Function) Value {
|
|
l := &Lookup{
|
|
X: e.m,
|
|
Index: e.k,
|
|
}
|
|
l.setPos(e.pos)
|
|
l.setType(e.t)
|
|
return fn.emit(l)
|
|
}
|
|
|
|
func (e *element) store(fn *Function, v Value) {
|
|
up := &MapUpdate{
|
|
Map: e.m,
|
|
Key: e.k,
|
|
Value: emitConv(fn, v, e.t),
|
|
}
|
|
up.pos = e.pos
|
|
fn.emit(up)
|
|
}
|
|
|
|
func (e *element) address(fn *Function) Value {
|
|
panic("map/string elements are not addressable")
|
|
}
|
|
|
|
func (e *element) typ() types.Type {
|
|
return e.t
|
|
}
|
|
|
|
// A blank is a dummy variable whose name is "_".
|
|
// It is not reified: loads are illegal and stores are ignored.
|
|
//
|
|
type blank struct{}
|
|
|
|
func (bl blank) load(fn *Function) Value {
|
|
panic("blank.load is illegal")
|
|
}
|
|
|
|
func (bl blank) store(fn *Function, v Value) {
|
|
s := &BlankStore{
|
|
Val: v,
|
|
}
|
|
fn.emit(s)
|
|
}
|
|
|
|
func (bl blank) address(fn *Function) Value {
|
|
panic("blank var is not addressable")
|
|
}
|
|
|
|
func (bl blank) typ() types.Type {
|
|
// This should be the type of the blank Ident; the typechecker
|
|
// doesn't provide this yet, but fortunately, we don't need it
|
|
// yet either.
|
|
panic("blank.typ is unimplemented")
|
|
}
|