| // Copyright 2006-2008 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef V8_SCOPES_H_ |
| #define V8_SCOPES_H_ |
| |
| #include "ast.h" |
| #include "hashmap.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| |
| // A hash map to support fast local variable declaration and lookup. |
| class LocalsMap: public HashMap { |
| public: |
| LocalsMap(); |
| |
| // Dummy constructor. This constructor doesn't set up the map |
| // properly so don't use it unless you have a good reason. |
| explicit LocalsMap(bool gotta_love_static_overloading); |
| |
| virtual ~LocalsMap(); |
| |
| Variable* Declare(Scope* scope, Handle<String> name, Variable::Mode mode, |
| bool is_valid_LHS, bool is_this); |
| |
| Variable* Lookup(Handle<String> name); |
| }; |
| |
| |
| // The dynamic scope part holds hash maps for the variables that will |
| // be looked up dynamically from within eval and with scopes. The objects |
| // are allocated on-demand from Scope::NonLocal to avoid wasting memory |
| // and setup time for scopes that don't need them. |
| class DynamicScopePart : public ZoneObject { |
| public: |
| LocalsMap* GetMap(Variable::Mode mode) { |
| int index = mode - Variable::DYNAMIC; |
| ASSERT(index >= 0 && index < 3); |
| return &maps_[index]; |
| } |
| |
| private: |
| LocalsMap maps_[3]; |
| }; |
| |
| |
| // Global invariants after AST construction: Each reference (i.e. identifier) |
| // to a JavaScript variable (including global properties) is represented by a |
| // VariableProxy node. Immediately after AST construction and before variable |
| // allocation, most VariableProxy nodes are "unresolved", i.e. not bound to a |
| // corresponding variable (though some are bound during parse time). Variable |
| // allocation binds each unresolved VariableProxy to one Variable and assigns |
| // a location. Note that many VariableProxy nodes may refer to the same Java- |
| // Script variable. |
| |
| class Scope: public ZoneObject { |
| public: |
| // --------------------------------------------------------------------------- |
| // Construction |
| |
| enum Type { |
| EVAL_SCOPE, // the top-level scope for an 'eval' source |
| FUNCTION_SCOPE, // the top-level scope for a function |
| GLOBAL_SCOPE // the top-level scope for a program or a top-level eval |
| }; |
| |
| Scope(); |
| Scope(Scope* outer_scope, Type type); |
| |
| virtual ~Scope() { } |
| |
| // The scope name is only used for printing/debugging. |
| void SetScopeName(Handle<String> scope_name) { scope_name_ = scope_name; } |
| |
| void Initialize(bool inside_with); |
| |
| |
| // --------------------------------------------------------------------------- |
| // Declarations |
| |
| // Lookup a variable in this scope. Returns the variable or NULL if not found. |
| virtual Variable* LookupLocal(Handle<String> name); |
| |
| // Lookup a variable in this scope or outer scopes. |
| // Returns the variable or NULL if not found. |
| virtual Variable* Lookup(Handle<String> name); |
| |
| // Declare the function variable for a function literal. This variable |
| // is in an intermediate scope between this function scope and the the |
| // outer scope. Only possible for function scopes; at most one variable. |
| Variable* DeclareFunctionVar(Handle<String> name); |
| |
| // Declare a variable in this scope. If the variable has been |
| // declared before, the previously declared variable is returned. |
| virtual Variable* Declare(Handle<String> name, Variable::Mode mode); |
| |
| // Add a parameter to the parameter list. The parameter must have been |
| // declared via Declare. The same parameter may occur more then once in |
| // the parameter list; they must be added in source order, from left to |
| // right. |
| void AddParameter(Variable* var); |
| |
| // Create a new unresolved variable. |
| virtual VariableProxy* NewUnresolved(Handle<String> name, bool inside_with); |
| |
| // Remove a unresolved variable. During parsing, an unresolved variable |
| // may have been added optimistically, but then only the variable name |
| // was used (typically for labels). If the variable was not declared, the |
| // addition introduced a new unresolved variable which may end up being |
| // allocated globally as a "ghost" variable. RemoveUnresolved removes |
| // such a variable again if it was added; otherwise this is a no-op. |
| void RemoveUnresolved(VariableProxy* var); |
| |
| // Creates a new temporary variable in this scope and binds a proxy to it. |
| // The name is only used for printing and cannot be used to find the variable. |
| // In particular, the only way to get hold of the temporary is by keeping the |
| // VariableProxy* around. |
| virtual VariableProxy* NewTemporary(Handle<String> name); |
| |
| // Adds the specific declaration node to the list of declarations in |
| // this scope. The declarations are processed as part of entering |
| // the scope; see codegen.cc:ProcessDeclarations. |
| void AddDeclaration(Declaration* declaration); |
| |
| // --------------------------------------------------------------------------- |
| // Illegal redeclaration support. |
| |
| // Set an expression node that will be executed when the scope is |
| // entered. We only keep track of one illegal redeclaration node per |
| // scope - the first one - so if you try to set it multiple times |
| // the additional requests will be silently ignored. |
| void SetIllegalRedeclaration(Expression* expression); |
| |
| // Visit the illegal redeclaration expression. Do not call if the |
| // scope doesn't have an illegal redeclaration node. |
| void VisitIllegalRedeclaration(AstVisitor* visitor); |
| |
| // Check if the scope has (at least) one illegal redeclaration. |
| bool HasIllegalRedeclaration() const { return illegal_redecl_ != NULL; } |
| |
| |
| // --------------------------------------------------------------------------- |
| // Scope-specific info. |
| |
| // Inform the scope that the corresponding code contains a with statement. |
| void RecordWithStatement() { scope_contains_with_ = true; } |
| |
| // Inform the scope that the corresponding code contains an eval call. |
| void RecordEvalCall() { scope_calls_eval_ = true; } |
| |
| |
| // --------------------------------------------------------------------------- |
| // Predicates. |
| |
| // Specific scope types. |
| bool is_eval_scope() const { return type_ == EVAL_SCOPE; } |
| bool is_function_scope() const { return type_ == FUNCTION_SCOPE; } |
| bool is_global_scope() const { return type_ == GLOBAL_SCOPE; } |
| |
| // Information about which scopes calls eval. |
| bool calls_eval() const { return scope_calls_eval_; } |
| bool outer_scope_calls_eval() const { return outer_scope_calls_eval_; } |
| |
| // Is this scope inside a with statement. |
| bool inside_with() const { return scope_inside_with_; } |
| // Does this scope contain a with statement. |
| bool contains_with() const { return scope_contains_with_; } |
| |
| // The scope immediately surrounding this scope, or NULL. |
| Scope* outer_scope() const { return outer_scope_; } |
| |
| // --------------------------------------------------------------------------- |
| // Accessors. |
| |
| // The variable corresponding to the (function) receiver. |
| VariableProxy* receiver() const { return receiver_; } |
| |
| // The variable holding the function literal for named function |
| // literals, or NULL. |
| // Only valid for function scopes. |
| Variable* function() const { |
| ASSERT(is_function_scope()); |
| return function_; |
| } |
| |
| // Parameters. The left-most parameter has index 0. |
| // Only valid for function scopes. |
| Variable* parameter(int index) const { |
| ASSERT(is_function_scope()); |
| return params_[index]; |
| } |
| |
| int num_parameters() const { return params_.length(); } |
| |
| // The local variable 'arguments' if we need to allocate it; NULL otherwise. |
| // If arguments() exist, arguments_shadow() exists, too. |
| VariableProxy* arguments() const { return arguments_; } |
| |
| // The '.arguments' shadow variable if we need to allocate it; NULL otherwise. |
| // If arguments_shadow() exist, arguments() exists, too. |
| VariableProxy* arguments_shadow() const { return arguments_shadow_; } |
| |
| // Declarations list. |
| ZoneList<Declaration*>* declarations() { return &decls_; } |
| |
| |
| |
| // --------------------------------------------------------------------------- |
| // Variable allocation. |
| |
| // Collect all used locals in this scope. |
| template<class Allocator> |
| void CollectUsedVariables(List<Variable*, Allocator>* locals); |
| |
| // Resolve and fill in the allocation information for all variables |
| // in this scopes. Must be called *after* all scopes have been |
| // processed (parsed) to ensure that unresolved variables can be |
| // resolved properly. |
| // |
| // In the case of code compiled and run using 'eval', the context |
| // parameter is the context in which eval was called. In all other |
| // cases the context parameter is an empty handle. |
| void AllocateVariables(Handle<Context> context); |
| |
| // Result of variable allocation. |
| int num_stack_slots() const { return num_stack_slots_; } |
| int num_heap_slots() const { return num_heap_slots_; } |
| |
| // Make sure this scope and all outer scopes are eagerly compiled. |
| void ForceEagerCompilation() { force_eager_compilation_ = true; } |
| |
| // Determine if we can use lazy compilation for this scope. |
| bool AllowsLazyCompilation() const; |
| |
| // True if the outer context of this scope is always the global context. |
| bool HasTrivialOuterContext() const; |
| |
| // The number of contexts between this and scope; zero if this == scope. |
| int ContextChainLength(Scope* scope); |
| |
| |
| // --------------------------------------------------------------------------- |
| // Debugging. |
| |
| #ifdef DEBUG |
| void Print(int n = 0); // n = indentation; n < 0 => don't print recursively |
| #endif |
| |
| // --------------------------------------------------------------------------- |
| // Implementation. |
| protected: |
| friend class ParserFactory; |
| |
| // Scope tree. |
| Scope* outer_scope_; // the immediately enclosing outer scope, or NULL |
| ZoneList<Scope*> inner_scopes_; // the immediately enclosed inner scopes |
| |
| // The scope type. |
| Type type_; |
| |
| // Debugging support. |
| Handle<String> scope_name_; |
| |
| // The variables declared in this scope: |
| // all user-declared variables (incl. parameters) |
| LocalsMap locals_; |
| // compiler-allocated (user-invisible) temporaries |
| ZoneList<Variable*> temps_; |
| // parameter list in source order |
| ZoneList<Variable*> params_; |
| // variables that must be looked up dynamically |
| DynamicScopePart* dynamics_; |
| // unresolved variables referred to from this scope |
| ZoneList<VariableProxy*> unresolved_; |
| // declarations |
| ZoneList<Declaration*> decls_; |
| // convenience variable |
| VariableProxy* receiver_; |
| // function variable, if any; function scopes only |
| Variable* function_; |
| // convenience variable; function scopes only |
| VariableProxy* arguments_; |
| // convenience variable; function scopes only |
| VariableProxy* arguments_shadow_; |
| |
| // Illegal redeclaration. |
| Expression* illegal_redecl_; |
| |
| // Scope-specific information. |
| bool scope_inside_with_; // this scope is inside a 'with' of some outer scope |
| bool scope_contains_with_; // this scope contains a 'with' statement |
| bool scope_calls_eval_; // this scope contains an 'eval' call |
| |
| // Computed via PropagateScopeInfo. |
| bool outer_scope_calls_eval_; |
| bool inner_scope_calls_eval_; |
| bool outer_scope_is_eval_scope_; |
| bool force_eager_compilation_; |
| |
| // Computed via AllocateVariables; function scopes only. |
| int num_stack_slots_; |
| int num_heap_slots_; |
| |
| // Create a non-local variable with a given name. |
| // These variables are looked up dynamically at runtime. |
| Variable* NonLocal(Handle<String> name, Variable::Mode mode); |
| |
| // Variable resolution. |
| Variable* LookupRecursive(Handle<String> name, |
| bool inner_lookup, |
| Variable** invalidated_local); |
| void ResolveVariable(Scope* global_scope, |
| Handle<Context> context, |
| VariableProxy* proxy); |
| void ResolveVariablesRecursively(Scope* global_scope, |
| Handle<Context> context); |
| |
| // Scope analysis. |
| bool PropagateScopeInfo(bool outer_scope_calls_eval, |
| bool outer_scope_is_eval_scope); |
| bool HasTrivialContext() const; |
| |
| // Predicates. |
| bool MustAllocate(Variable* var); |
| bool MustAllocateInContext(Variable* var); |
| bool HasArgumentsParameter(); |
| |
| // Variable allocation. |
| void AllocateStackSlot(Variable* var); |
| void AllocateHeapSlot(Variable* var); |
| void AllocateParameterLocals(); |
| void AllocateNonParameterLocal(Variable* var); |
| void AllocateNonParameterLocals(); |
| void AllocateVariablesRecursively(); |
| }; |
| |
| |
| class DummyScope : public Scope { |
| public: |
| DummyScope() { |
| outer_scope_ = this; |
| } |
| |
| virtual Variable* Lookup(Handle<String> name) { return NULL; } |
| virtual Variable* Declare(Handle<String> name, Variable::Mode mode) { |
| return NULL; |
| } |
| virtual VariableProxy* NewUnresolved(Handle<String> name, bool inside_with) { |
| return NULL; |
| } |
| virtual VariableProxy* NewTemporary(Handle<String> name) { return NULL; } |
| }; |
| |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_SCOPES_H_ |