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Diffstat (limited to 'libgo/go/exp/eval/scope.go')
-rw-r--r--libgo/go/exp/eval/scope.go207
1 files changed, 0 insertions, 207 deletions
diff --git a/libgo/go/exp/eval/scope.go b/libgo/go/exp/eval/scope.go
deleted file mode 100644
index 66305de25f0..00000000000
--- a/libgo/go/exp/eval/scope.go
+++ /dev/null
@@ -1,207 +0,0 @@
-// Copyright 2009 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 eval
-
-import (
- "go/token"
- "log"
-)
-
-/*
- * Blocks and scopes
- */
-
-// A definition can be a *Variable, *Constant, or Type.
-type Def interface {
- Pos() token.Pos
-}
-
-type Variable struct {
- VarPos token.Pos
- // Index of this variable in the Frame structure
- Index int
- // Static type of this variable
- Type Type
- // Value of this variable. This is only used by Scope.NewFrame;
- // therefore, it is useful for global scopes but cannot be used
- // in function scopes.
- Init Value
-}
-
-func (v *Variable) Pos() token.Pos {
- return v.VarPos
-}
-
-type Constant struct {
- ConstPos token.Pos
- Type Type
- Value Value
-}
-
-func (c *Constant) Pos() token.Pos {
- return c.ConstPos
-}
-
-// A block represents a definition block in which a name may not be
-// defined more than once.
-type block struct {
- // The block enclosing this one, including blocks in other
- // scopes.
- outer *block
- // The nested block currently being compiled, or nil.
- inner *block
- // The Scope containing this block.
- scope *Scope
- // The Variables, Constants, and Types defined in this block.
- defs map[string]Def
- // The index of the first variable defined in this block.
- // This must be greater than the index of any variable defined
- // in any parent of this block within the same Scope at the
- // time this block is entered.
- offset int
- // The number of Variables defined in this block.
- numVars int
- // If global, do not allocate new vars and consts in
- // the frame; assume that the refs will be compiled in
- // using defs[name].Init.
- global bool
-}
-
-// A Scope is the compile-time analogue of a Frame, which captures
-// some subtree of blocks.
-type Scope struct {
- // The root block of this scope.
- *block
- // The maximum number of variables required at any point in
- // this Scope. This determines the number of slots needed in
- // Frame's created from this Scope at run-time.
- maxVars int
-}
-
-func (b *block) enterChild() *block {
- if b.inner != nil && b.inner.scope == b.scope {
- log.Panic("Failed to exit child block before entering another child")
- }
- sub := &block{
- outer: b,
- scope: b.scope,
- defs: make(map[string]Def),
- offset: b.offset + b.numVars,
- }
- b.inner = sub
- return sub
-}
-
-func (b *block) exit() {
- if b.outer == nil {
- log.Panic("Cannot exit top-level block")
- }
- if b.outer.scope == b.scope {
- if b.outer.inner != b {
- log.Panic("Already exited block")
- }
- if b.inner != nil && b.inner.scope == b.scope {
- log.Panic("Exit of parent block without exit of child block")
- }
- }
- b.outer.inner = nil
-}
-
-func (b *block) ChildScope() *Scope {
- if b.inner != nil && b.inner.scope == b.scope {
- log.Panic("Failed to exit child block before entering a child scope")
- }
- sub := b.enterChild()
- sub.offset = 0
- sub.scope = &Scope{sub, 0}
- return sub.scope
-}
-
-func (b *block) DefineVar(name string, pos token.Pos, t Type) (*Variable, Def) {
- if prev, ok := b.defs[name]; ok {
- return nil, prev
- }
- v := b.defineSlot(t, false)
- v.VarPos = pos
- b.defs[name] = v
- return v, nil
-}
-
-func (b *block) DefineTemp(t Type) *Variable { return b.defineSlot(t, true) }
-
-func (b *block) defineSlot(t Type, temp bool) *Variable {
- if b.inner != nil && b.inner.scope == b.scope {
- log.Panic("Failed to exit child block before defining variable")
- }
- index := -1
- if !b.global || temp {
- index = b.offset + b.numVars
- b.numVars++
- if index >= b.scope.maxVars {
- b.scope.maxVars = index + 1
- }
- }
- v := &Variable{token.NoPos, index, t, nil}
- return v
-}
-
-func (b *block) DefineConst(name string, pos token.Pos, t Type, v Value) (*Constant, Def) {
- if prev, ok := b.defs[name]; ok {
- return nil, prev
- }
- c := &Constant{pos, t, v}
- b.defs[name] = c
- return c, nil
-}
-
-func (b *block) DefineType(name string, pos token.Pos, t Type) Type {
- if _, ok := b.defs[name]; ok {
- return nil
- }
- nt := &NamedType{pos, name, nil, true, make(map[string]Method)}
- if t != nil {
- nt.Complete(t)
- }
- b.defs[name] = nt
- return nt
-}
-
-func (b *block) Lookup(name string) (bl *block, level int, def Def) {
- for b != nil {
- if d, ok := b.defs[name]; ok {
- return b, level, d
- }
- if b.outer != nil && b.scope != b.outer.scope {
- level++
- }
- b = b.outer
- }
- return nil, 0, nil
-}
-
-func (s *Scope) NewFrame(outer *Frame) *Frame { return outer.child(s.maxVars) }
-
-/*
- * Frames
- */
-
-type Frame struct {
- Outer *Frame
- Vars []Value
-}
-
-func (f *Frame) Get(level int, index int) Value {
- for ; level > 0; level-- {
- f = f.Outer
- }
- return f.Vars[index]
-}
-
-func (f *Frame) child(numVars int) *Frame {
- // TODO(austin) This is probably rather expensive. All values
- // require heap allocation and zeroing them when we execute a
- // definition typically requires some computation.
- return &Frame{f, make([]Value, numVars)}
-}