| // Copyright 2011 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef V8_VARIABLES_H_ |
| #define V8_VARIABLES_H_ |
| |
| #include "src/ast-value-factory.h" |
| #include "src/interface.h" |
| #include "src/zone.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // The AST refers to variables via VariableProxies - placeholders for the actual |
| // variables. Variables themselves are never directly referred to from the AST, |
| // they are maintained by scopes, and referred to from VariableProxies and Slots |
| // after binding and variable allocation. |
| |
| class Variable: public ZoneObject { |
| public: |
| enum Kind { |
| NORMAL, |
| THIS, |
| ARGUMENTS |
| }; |
| |
| enum Location { |
| // Before and during variable allocation, a variable whose location is |
| // not yet determined. After allocation, a variable looked up as a |
| // property on the global object (and possibly absent). name() is the |
| // variable name, index() is invalid. |
| UNALLOCATED, |
| |
| // A slot in the parameter section on the stack. index() is the |
| // parameter index, counting left-to-right. The receiver is index -1; |
| // the first parameter is index 0. |
| PARAMETER, |
| |
| // A slot in the local section on the stack. index() is the variable |
| // index in the stack frame, starting at 0. |
| LOCAL, |
| |
| // An indexed slot in a heap context. index() is the variable index in |
| // the context object on the heap, starting at 0. scope() is the |
| // corresponding scope. |
| CONTEXT, |
| |
| // A named slot in a heap context. name() is the variable name in the |
| // context object on the heap, with lookup starting at the current |
| // context. index() is invalid. |
| LOOKUP |
| }; |
| |
| Variable(Scope* scope, const AstRawString* name, VariableMode mode, |
| bool is_valid_ref, Kind kind, InitializationFlag initialization_flag, |
| MaybeAssignedFlag maybe_assigned_flag = kNotAssigned, |
| Interface* interface = Interface::NewValue()); |
| |
| // Printing support |
| static const char* Mode2String(VariableMode mode); |
| |
| bool IsValidReference() { return is_valid_ref_; } |
| |
| // The source code for an eval() call may refer to a variable that is |
| // in an outer scope about which we don't know anything (it may not |
| // be the global scope). scope() is NULL in that case. Currently the |
| // scope is only used to follow the context chain length. |
| Scope* scope() const { return scope_; } |
| |
| Handle<String> name() const { return name_->string(); } |
| const AstRawString* raw_name() const { return name_; } |
| VariableMode mode() const { return mode_; } |
| bool has_forced_context_allocation() const { |
| return force_context_allocation_; |
| } |
| void ForceContextAllocation() { |
| DCHECK(mode_ != TEMPORARY); |
| force_context_allocation_ = true; |
| } |
| bool is_used() { return is_used_; } |
| void set_is_used() { is_used_ = true; } |
| MaybeAssignedFlag maybe_assigned() const { return maybe_assigned_; } |
| void set_maybe_assigned() { maybe_assigned_ = kMaybeAssigned; } |
| |
| int initializer_position() { return initializer_position_; } |
| void set_initializer_position(int pos) { initializer_position_ = pos; } |
| |
| bool IsVariable(Handle<String> n) const { |
| return !is_this() && name().is_identical_to(n); |
| } |
| |
| bool IsUnallocated() const { return location_ == UNALLOCATED; } |
| bool IsParameter() const { return location_ == PARAMETER; } |
| bool IsStackLocal() const { return location_ == LOCAL; } |
| bool IsStackAllocated() const { return IsParameter() || IsStackLocal(); } |
| bool IsContextSlot() const { return location_ == CONTEXT; } |
| bool IsLookupSlot() const { return location_ == LOOKUP; } |
| bool IsGlobalObjectProperty() const; |
| |
| bool is_dynamic() const { return IsDynamicVariableMode(mode_); } |
| bool is_const_mode() const { return IsImmutableVariableMode(mode_); } |
| bool binding_needs_init() const { |
| return initialization_flag_ == kNeedsInitialization; |
| } |
| |
| bool is_this() const { return kind_ == THIS; } |
| bool is_arguments() const { return kind_ == ARGUMENTS; } |
| |
| // True if the variable is named eval and not known to be shadowed. |
| bool is_possibly_eval(Isolate* isolate) const { |
| return IsVariable(isolate->factory()->eval_string()); |
| } |
| |
| Variable* local_if_not_shadowed() const { |
| DCHECK(mode_ == DYNAMIC_LOCAL && local_if_not_shadowed_ != NULL); |
| return local_if_not_shadowed_; |
| } |
| |
| void set_local_if_not_shadowed(Variable* local) { |
| local_if_not_shadowed_ = local; |
| } |
| |
| Location location() const { return location_; } |
| int index() const { return index_; } |
| InitializationFlag initialization_flag() const { |
| return initialization_flag_; |
| } |
| Interface* interface() const { return interface_; } |
| |
| void AllocateTo(Location location, int index) { |
| location_ = location; |
| index_ = index; |
| } |
| |
| static int CompareIndex(Variable* const* v, Variable* const* w); |
| |
| private: |
| Scope* scope_; |
| const AstRawString* name_; |
| VariableMode mode_; |
| Kind kind_; |
| Location location_; |
| int index_; |
| int initializer_position_; |
| |
| // If this field is set, this variable references the stored locally bound |
| // variable, but it might be shadowed by variable bindings introduced by |
| // sloppy 'eval' calls between the reference scope (inclusive) and the |
| // binding scope (exclusive). |
| Variable* local_if_not_shadowed_; |
| |
| // Valid as a reference? (const and this are not valid, for example) |
| bool is_valid_ref_; |
| |
| // Usage info. |
| bool force_context_allocation_; // set by variable resolver |
| bool is_used_; |
| InitializationFlag initialization_flag_; |
| MaybeAssignedFlag maybe_assigned_; |
| |
| // Module type info. |
| Interface* interface_; |
| }; |
| |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_VARIABLES_H_ |