| // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| #ifndef VM_SCOPES_H_ |
| #define VM_SCOPES_H_ |
| |
| #include "platform/assert.h" |
| #include "platform/globals.h" |
| #include "vm/allocation.h" |
| #include "vm/growable_array.h" |
| #include "vm/object.h" |
| #include "vm/raw_object.h" |
| #include "vm/symbols.h" |
| #include "vm/token.h" |
| |
| namespace dart { |
| |
| class LocalScope; |
| |
| |
| class LocalVariable : public ZoneAllocated { |
| public: |
| LocalVariable(intptr_t token_pos, |
| const String& name, |
| const AbstractType& type) |
| : token_pos_(token_pos), |
| name_(name), |
| owner_(NULL), |
| type_(type), |
| const_value_(NULL), |
| is_final_(false), |
| is_captured_(false), |
| is_invisible_(false), |
| is_captured_parameter_(false), |
| index_(LocalVariable::kUninitializedIndex) { |
| ASSERT(type.IsZoneHandle() || type.IsReadOnlyHandle()); |
| ASSERT(type.IsFinalized()); |
| ASSERT(name.IsSymbol()); |
| } |
| |
| intptr_t token_pos() const { return token_pos_; } |
| const String& name() const { return name_; } |
| LocalScope* owner() const { return owner_; } |
| void set_owner(LocalScope* owner) { |
| ASSERT(owner_ == NULL); |
| owner_ = owner; |
| } |
| |
| const AbstractType& type() const { return type_; } |
| |
| bool is_final() const { return is_final_; } |
| void set_is_final() { is_final_ = true; } |
| |
| bool is_captured() const { return is_captured_; } |
| void set_is_captured() { is_captured_ = true; } |
| |
| bool HasIndex() const { |
| return index_ != kUninitializedIndex; |
| } |
| int index() const { |
| ASSERT(HasIndex()); |
| return index_; |
| } |
| |
| // Assign an index to a local. |
| void set_index(int index) { |
| ASSERT(index != kUninitializedIndex); |
| index_ = index; |
| } |
| |
| void set_invisible(bool value) { |
| is_invisible_ = value; |
| } |
| bool is_invisible() const { return is_invisible_; } |
| |
| bool is_captured_parameter() const { return is_captured_parameter_; } |
| void set_is_captured_parameter(bool value) { |
| is_captured_parameter_ = value; |
| } |
| |
| // By convention, internal variables start with a colon. |
| bool IsInternal() const { |
| return name_.CharAt(0) == ':'; |
| } |
| |
| bool IsConst() const { |
| return const_value_ != NULL; |
| } |
| |
| void SetConstValue(const Instance& value) { |
| ASSERT(value.IsZoneHandle() || value.IsReadOnlyHandle()); |
| const_value_ = &value; |
| } |
| |
| const Instance* ConstValue() const { |
| ASSERT(IsConst()); |
| return const_value_; |
| } |
| |
| bool Equals(const LocalVariable& other) const; |
| |
| // Map the frame index to a bit-vector index. Assumes the variable is |
| // allocated to the frame. |
| // var_count is the total number of stack-allocated variables including |
| // all parameters. |
| int BitIndexIn(intptr_t var_count) const; |
| |
| private: |
| static const int kUninitializedIndex = INT_MIN; |
| |
| const intptr_t token_pos_; |
| const String& name_; |
| LocalScope* owner_; // Local scope declaring this variable. |
| |
| const AbstractType& type_; // Declaration type of local variable. |
| |
| const Instance* const_value_; // NULL or compile-time const value. |
| |
| bool is_final_; // If true, this variable is readonly. |
| bool is_captured_; // If true, this variable lives in the context, otherwise |
| // in the stack frame. |
| bool is_invisible_; |
| bool is_captured_parameter_; |
| int index_; // Allocation index in words relative to frame pointer (if not |
| // captured), or relative to the context pointer (if captured). |
| |
| friend class LocalScope; |
| DISALLOW_COPY_AND_ASSIGN(LocalVariable); |
| }; |
| |
| |
| class NameReference : public ZoneAllocated { |
| public: |
| NameReference(intptr_t token_pos, const String& name) |
| : token_pos_(token_pos), |
| name_(name) { |
| ASSERT(name.IsSymbol()); |
| } |
| const String& name() const { return name_; } |
| intptr_t token_pos() const { return token_pos_; } |
| void set_token_pos(intptr_t value) { token_pos_ = value; } |
| private: |
| intptr_t token_pos_; |
| const String& name_; |
| }; |
| |
| |
| class SourceLabel : public ZoneAllocated { |
| public: |
| enum Kind { |
| kFor, |
| kWhile, |
| kDoWhile, |
| kSwitch, |
| kCase, |
| kTry, |
| kCatch, |
| kForward, |
| kStatement // Any statement other than the above |
| }; |
| |
| SourceLabel(intptr_t token_pos, const String& name, Kind kind) |
| : token_pos_(token_pos), |
| name_(name), |
| owner_(NULL), |
| kind_(kind) { |
| ASSERT(name.IsSymbol()); |
| } |
| |
| static SourceLabel* New(intptr_t token_pos, String* name, Kind kind) { |
| if (name != NULL) { |
| return new SourceLabel(token_pos, *name, kind); |
| } else { |
| return new SourceLabel(token_pos, |
| Symbols::DefaultLabel(), |
| kind); |
| } |
| } |
| |
| intptr_t token_pos() const { return token_pos_; } |
| const String& name() const { return name_; } |
| LocalScope* owner() const { return owner_; } |
| void set_owner(LocalScope* owner) { |
| ASSERT(owner_ == NULL); |
| owner_ = owner; |
| } |
| |
| Kind kind() const { return kind_; } |
| |
| // Returns the function level of the scope in which the label is defined. |
| int FunctionLevel() const; |
| |
| void ResolveForwardReference() { kind_ = kCase; } |
| |
| private: |
| const intptr_t token_pos_; |
| const String& name_; |
| LocalScope* owner_; // Local scope declaring this label. |
| |
| Kind kind_; |
| |
| DISALLOW_COPY_AND_ASSIGN(SourceLabel); |
| }; |
| |
| |
| class LocalScope : public ZoneAllocated { |
| public: |
| LocalScope(LocalScope* parent, int function_level, int loop_level); |
| |
| LocalScope* parent() const { return parent_; } |
| LocalScope* child() const { return child_; } |
| LocalScope* sibling() const { return sibling_; } |
| int function_level() const { return function_level_; } |
| int loop_level() const { return loop_level_; } |
| |
| // Check if this scope is nested within the passed in scope. |
| bool IsNestedWithin(LocalScope* scope) const; |
| |
| // The context level is only set in a scope that is either the owner scope of |
| // a captured variable or that is the owner scope of a context. |
| bool HasContextLevel() const { |
| return context_level_ != kUnitializedContextLevel; |
| } |
| int context_level() const { |
| ASSERT(HasContextLevel()); |
| return context_level_; |
| } |
| void set_context_level(int context_level) { |
| ASSERT(!HasContextLevel()); |
| ASSERT(context_level != kUnitializedContextLevel); |
| context_level_ = context_level; |
| } |
| |
| intptr_t begin_token_pos() const { return begin_token_pos_; } |
| void set_begin_token_pos(intptr_t value) { begin_token_pos_ = value; } |
| |
| intptr_t end_token_pos() const { return end_token_pos_; } |
| void set_end_token_pos(intptr_t value) { end_token_pos_ = value; } |
| |
| // The number of variables allocated in the context and belonging to this |
| // scope and to its children at the same loop level. |
| int num_context_variables() const { return num_context_variables_; } |
| |
| // Add a variable to the scope. Returns false if a variable with the |
| // same name is already present. |
| bool AddVariable(LocalVariable* variable); |
| |
| // Insert a formal parameter variable to the scope at the given position, |
| // possibly in front of aliases already added with AddVariable. |
| // Returns false if a variable with the same name is already present. |
| bool InsertParameterAt(intptr_t pos, LocalVariable* parameter); |
| |
| // Add a label to the scope. Returns false if a label with the same name |
| // is already present. |
| bool AddLabel(SourceLabel* label); |
| |
| // Lookup a variable in this scope only. |
| LocalVariable* LocalLookupVariable(const String& name) const; |
| |
| // Lookup a label in this scope only. |
| SourceLabel* LocalLookupLabel(const String& name) const; |
| |
| // Lookup a variable in this scope and its parents. If the variable |
| // is found in a parent scope and 'test_only' is not true, we insert |
| // aliases of the variable in the current and intermediate scopes up to |
| // the declaration scope in order to detect "used before declared" errors. |
| // We mark a variable as 'captured' when applicable. |
| LocalVariable* LookupVariable(const String& name, bool test_only); |
| |
| // Lookup a label in this scope and its parents. |
| SourceLabel* LookupLabel(const String& name); |
| |
| // Lookup the "innermost" label that labels a for, while, do, or switch |
| // statement. |
| SourceLabel* LookupInnermostLabel(Token::Kind jump_kind); |
| |
| // Lookup scope of outer switch statement at same function level. |
| // Returns NULL if this scope is not embedded in a switch. |
| LocalScope* LookupSwitchScope(); |
| |
| // Mark this variable as captured by this scope. |
| void CaptureVariable(LocalVariable* variable); |
| |
| // Look for unresolved forward references to labels in this scope. |
| // If there are any, propagate the forward reference to the next |
| // outer scope of a switch statement. If there is no outer switch |
| // statement, return the first unresolved label found. |
| SourceLabel* CheckUnresolvedLabels(); |
| |
| // Accessing the variables in the scope. |
| intptr_t num_variables() const { return variables_.length(); } |
| LocalVariable* VariableAt(intptr_t index) const { |
| ASSERT((index >= 0) && (index < variables_.length())); |
| return variables_[index]; |
| } |
| |
| // Count the captured variables belonging to outer scopes and referenced in |
| // this local scope. |
| int NumCapturedVariables() const; |
| |
| // Add a reference to the given name into this scope and the enclosing |
| // scopes that do not have a local variable declaration for this name |
| // already. |
| void AddReferencedName(intptr_t token_pos, const String& name); |
| intptr_t PreviousReferencePos(const String& name) const; |
| |
| // Allocate both captured and non-captured variables declared in this scope |
| // and in its children scopes of the same function level. Allocating means |
| // assigning a frame slot index or a context slot index. |
| // Parameters to be allocated in the frame must all appear in the top scope |
| // and not in its children (we do not yet handle register parameters). |
| // Locals must be listed after parameters in top scope and in its children. |
| // Two locals in different sibling scopes may share the same frame slot. |
| // Return the index of the next available frame slot. |
| int AllocateVariables(int first_parameter_index, |
| int num_parameters, |
| int first_frame_index, |
| LocalScope* context_owner, |
| bool* found_captured_variables); |
| |
| // Creates variable info for the scope and all its nested scopes. |
| // Must be called after AllocateVariables() has been called. |
| RawLocalVarDescriptors* GetVarDescriptors(const Function& func); |
| |
| // Create a ContextScope object describing all captured variables referenced |
| // from this scope and belonging to outer scopes. |
| RawContextScope* PreserveOuterScope(int current_context_level) const; |
| |
| // Mark all local variables that are accessible from this scope up to |
| // top_scope (included) as captured. |
| void CaptureLocalVariables(LocalScope* top_scope); |
| |
| // Creates a LocalScope representing the outer scope of a local function to be |
| // compiled. This outer scope contains the variables captured by the function |
| // as specified by the given ContextScope, which was created during the |
| // compilation of the enclosing function. |
| static LocalScope* RestoreOuterScope(const ContextScope& context_scope); |
| |
| // Create a ContextScope object which will capture "this" for an implicit |
| // closure object. |
| static RawContextScope* CreateImplicitClosureScope(const Function& func); |
| |
| private: |
| struct VarDesc { |
| const String* name; |
| RawLocalVarDescriptors::VarInfo info; |
| }; |
| |
| // Allocate the variable in the current context, possibly updating the current |
| // context owner scope, if the variable is the first one to be allocated at |
| // this loop level. |
| // The variable may belong to this scope or to any of its children, but at the |
| // same loop level. |
| void AllocateContextVariable(LocalVariable* variable, |
| LocalScope** context_owner); |
| |
| void CollectLocalVariables(GrowableArray<VarDesc>* vars, int16_t* scope_id); |
| |
| NameReference* FindReference(const String& name) const; |
| |
| static const int kUnitializedContextLevel = INT_MIN; |
| LocalScope* parent_; |
| LocalScope* child_; |
| LocalScope* sibling_; |
| int function_level_; // Reflects the nesting level of local functions. |
| int loop_level_; // Reflects the loop nesting level. |
| int context_level_; // Reflects the level of the runtime context. |
| int num_context_variables_; // Only set if this scope is a context owner. |
| intptr_t begin_token_pos_; // Token index of beginning of scope. |
| intptr_t end_token_pos_; // Token index of end of scope. |
| GrowableArray<LocalVariable*> variables_; |
| GrowableArray<SourceLabel*> labels_; |
| |
| // List of names referenced in this scope and its children that |
| // are not resolved to local variables. |
| GrowableArray<NameReference*> referenced_; |
| |
| DISALLOW_COPY_AND_ASSIGN(LocalScope); |
| }; |
| |
| } // namespace dart |
| |
| #endif // VM_SCOPES_H_ |