js/src/vm/BindingKind.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef vm_BindingKind_h
   8 #define vm_BindingKind_h
   9
  10 #include "mozilla/Assertions.h"  // MOZ_ASSERT, MOZ_ASSERT_IF
  11 #include "mozilla/Casting.h"     // mozilla::AssertedCast
  12
  13 #include <stdint.h>  // uint16_t, uint32_t
  14
  15 #include "vm/BytecodeUtil.h"  // LOCALNO_LIMIT, ENVCOORD_SLOT_LIMIT
  16
  17 namespace js {
  18
  19 enum class BindingKind : uint8_t {
  20   Import,
  21   FormalParameter,
  22   Var,
  23   Let,
  24   Const,
  25
  26   // So you think named lambda callee names are consts? Nope! They don't
  27   // throw when being assigned to in sloppy mode.
  28   NamedLambdaCallee,
  29
  30   // ClassBodyScope bindings that aren't bindings in the spec, but are put into
  31   // a scope as an implementation detail: `.privateBrand`,
  32   // `.staticInitializers`, private names, and private accessor functions.
  33   Synthetic,
  34
  35   // ClassBodyScope binding that stores the function object for a non-static
  36   // private method.
  37   PrivateMethod,
  38 };
  39
  40 static inline bool BindingKindIsLexical(BindingKind kind) {
  41   return kind == BindingKind::Let || kind == BindingKind::Const;
  42 }
  43
  44 class BindingLocation {
  45  public:
  46   enum class Kind {
  47     Global,
  48     Argument,
  49     Frame,
  50     Environment,
  51     Import,
  52     NamedLambdaCallee
  53   };
  54
  55  private:
  56   Kind kind_;
  57   uint32_t slot_;
  58
  59   BindingLocation(Kind kind, uint32_t slot) : kind_(kind), slot_(slot) {}
  60
  61  public:
  62   static BindingLocation Global() {
  63     return BindingLocation(Kind::Global, UINT32_MAX);
  64   }
  65
  66   static BindingLocation Argument(uint16_t slot) {
  67     return BindingLocation(Kind::Argument, slot);
  68   }
  69
  70   static BindingLocation Frame(uint32_t slot) {
  71     MOZ_ASSERT(slot < LOCALNO_LIMIT);
  72     return BindingLocation(Kind::Frame, slot);
  73   }
  74
  75   static BindingLocation Environment(uint32_t slot) {
  76     MOZ_ASSERT(slot < ENVCOORD_SLOT_LIMIT);
  77     return BindingLocation(Kind::Environment, slot);
  78   }
  79
  80   static BindingLocation Import() {
  81     return BindingLocation(Kind::Import, UINT32_MAX);
  82   }
  83
  84   static BindingLocation NamedLambdaCallee() {
  85     return BindingLocation(Kind::NamedLambdaCallee, UINT32_MAX);
  86   }
  87
  88   bool operator==(const BindingLocation& other) const {
  89     return kind_ == other.kind_ && slot_ == other.slot_;
  90   }
  91
  92   bool operator!=(const BindingLocation& other) const {
  93     return !operator==(other);
  94   }
  95
  96   Kind kind() const { return kind_; }
  97
  98   uint32_t slot() const {
  99     MOZ_ASSERT(kind_ == Kind::Frame || kind_ == Kind::Environment);
 100     return slot_;
 101   }
 102
 103   uint16_t argumentSlot() const {
 104     MOZ_ASSERT(kind_ == Kind::Argument);
 105     return mozilla::AssertedCast<uint16_t>(slot_);
 106   }
 107 };
 108
 109 }  // namespace js
 110
 111 #endif  // vm_BindingKind_h