Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 1 | // Copyright 2011 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #ifndef V8_AST_VARIABLES_H_ |
| 6 | #define V8_AST_VARIABLES_H_ |
| 7 | |
| 8 | #include "src/ast/ast-value-factory.h" |
| 9 | #include "src/zone.h" |
| 10 | |
| 11 | namespace v8 { |
| 12 | namespace internal { |
| 13 | |
| 14 | // The AST refers to variables via VariableProxies - placeholders for the actual |
| 15 | // variables. Variables themselves are never directly referred to from the AST, |
| 16 | // they are maintained by scopes, and referred to from VariableProxies and Slots |
| 17 | // after binding and variable allocation. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 18 | class Variable: public ZoneObject { |
| 19 | public: |
Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame] | 20 | enum Kind { NORMAL, FUNCTION, THIS, ARGUMENTS }; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 21 | |
| 22 | Variable(Scope* scope, const AstRawString* name, VariableMode mode, Kind kind, |
| 23 | InitializationFlag initialization_flag, |
| 24 | MaybeAssignedFlag maybe_assigned_flag = kNotAssigned); |
| 25 | |
| 26 | virtual ~Variable() {} |
| 27 | |
| 28 | // Printing support |
| 29 | static const char* Mode2String(VariableMode mode); |
| 30 | |
| 31 | // The source code for an eval() call may refer to a variable that is |
| 32 | // in an outer scope about which we don't know anything (it may not |
| 33 | // be the script scope). scope() is NULL in that case. Currently the |
| 34 | // scope is only used to follow the context chain length. |
| 35 | Scope* scope() const { return scope_; } |
| 36 | |
| 37 | // This is for adjusting the scope of temporaries used when desugaring |
| 38 | // parameter initializers. |
| 39 | void set_scope(Scope* scope) { scope_ = scope; } |
| 40 | |
| 41 | Handle<String> name() const { return name_->string(); } |
| 42 | const AstRawString* raw_name() const { return name_; } |
| 43 | VariableMode mode() const { return mode_; } |
| 44 | bool has_forced_context_allocation() const { |
| 45 | return force_context_allocation_; |
| 46 | } |
| 47 | void ForceContextAllocation() { |
| 48 | force_context_allocation_ = true; |
| 49 | } |
| 50 | bool is_used() { return is_used_; } |
| 51 | void set_is_used() { is_used_ = true; } |
| 52 | MaybeAssignedFlag maybe_assigned() const { return maybe_assigned_; } |
| 53 | void set_maybe_assigned() { maybe_assigned_ = kMaybeAssigned; } |
| 54 | |
| 55 | int initializer_position() { return initializer_position_; } |
| 56 | void set_initializer_position(int pos) { initializer_position_ = pos; } |
| 57 | |
| 58 | bool IsVariable(Handle<String> n) const { |
| 59 | return !is_this() && name().is_identical_to(n); |
| 60 | } |
| 61 | |
| 62 | bool IsUnallocated() const { |
| 63 | return location_ == VariableLocation::UNALLOCATED; |
| 64 | } |
| 65 | bool IsParameter() const { return location_ == VariableLocation::PARAMETER; } |
| 66 | bool IsStackLocal() const { return location_ == VariableLocation::LOCAL; } |
| 67 | bool IsStackAllocated() const { return IsParameter() || IsStackLocal(); } |
| 68 | bool IsContextSlot() const { return location_ == VariableLocation::CONTEXT; } |
| 69 | bool IsGlobalSlot() const { return location_ == VariableLocation::GLOBAL; } |
| 70 | bool IsUnallocatedOrGlobalSlot() const { |
| 71 | return IsUnallocated() || IsGlobalSlot(); |
| 72 | } |
| 73 | bool IsLookupSlot() const { return location_ == VariableLocation::LOOKUP; } |
| 74 | bool IsGlobalObjectProperty() const; |
| 75 | bool IsStaticGlobalObjectProperty() const; |
| 76 | |
| 77 | bool is_dynamic() const { return IsDynamicVariableMode(mode_); } |
| 78 | bool is_const_mode() const { return IsImmutableVariableMode(mode_); } |
| 79 | bool binding_needs_init() const { |
| 80 | return initialization_flag_ == kNeedsInitialization; |
| 81 | } |
| 82 | |
| 83 | bool is_function() const { return kind_ == FUNCTION; } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 84 | bool is_this() const { return kind_ == THIS; } |
| 85 | bool is_arguments() const { return kind_ == ARGUMENTS; } |
| 86 | |
| 87 | // For script scopes, the "this" binding is provided by a ScriptContext added |
| 88 | // to the global's ScriptContextTable. This binding might not statically |
| 89 | // resolve to a Variable::THIS binding, instead being DYNAMIC_LOCAL. However |
| 90 | // any variable named "this" does indeed refer to a Variable::THIS binding; |
| 91 | // the grammar ensures this to be the case. So wherever a "this" binding |
| 92 | // might be provided by the global, use HasThisName instead of is_this(). |
| 93 | bool HasThisName(Isolate* isolate) const { |
| 94 | return is_this() || *name() == *isolate->factory()->this_string(); |
| 95 | } |
| 96 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 97 | // True if the variable is named eval and not known to be shadowed. |
| 98 | bool is_possibly_eval(Isolate* isolate) const { |
| 99 | return IsVariable(isolate->factory()->eval_string()); |
| 100 | } |
| 101 | |
| 102 | Variable* local_if_not_shadowed() const { |
| 103 | DCHECK(mode_ == DYNAMIC_LOCAL && local_if_not_shadowed_ != NULL); |
| 104 | return local_if_not_shadowed_; |
| 105 | } |
| 106 | |
| 107 | void set_local_if_not_shadowed(Variable* local) { |
| 108 | local_if_not_shadowed_ = local; |
| 109 | } |
| 110 | |
| 111 | VariableLocation location() const { return location_; } |
| 112 | int index() const { return index_; } |
| 113 | InitializationFlag initialization_flag() const { |
| 114 | return initialization_flag_; |
| 115 | } |
| 116 | |
| 117 | void AllocateTo(VariableLocation location, int index) { |
| 118 | location_ = location; |
| 119 | index_ = index; |
| 120 | } |
| 121 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 122 | static int CompareIndex(Variable* const* v, Variable* const* w); |
| 123 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 124 | private: |
| 125 | Scope* scope_; |
| 126 | const AstRawString* name_; |
| 127 | VariableMode mode_; |
| 128 | Kind kind_; |
| 129 | VariableLocation location_; |
| 130 | int index_; |
| 131 | int initializer_position_; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 132 | |
| 133 | // If this field is set, this variable references the stored locally bound |
| 134 | // variable, but it might be shadowed by variable bindings introduced by |
| 135 | // sloppy 'eval' calls between the reference scope (inclusive) and the |
| 136 | // binding scope (exclusive). |
| 137 | Variable* local_if_not_shadowed_; |
| 138 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 139 | // Usage info. |
| 140 | bool force_context_allocation_; // set by variable resolver |
| 141 | bool is_used_; |
| 142 | InitializationFlag initialization_flag_; |
| 143 | MaybeAssignedFlag maybe_assigned_; |
| 144 | }; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 145 | } // namespace internal |
| 146 | } // namespace v8 |
| 147 | |
| 148 | #endif // V8_AST_VARIABLES_H_ |