// 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
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_SCOPEINFO_H_
#define V8_SCOPEINFO_H_
#include "variables.h"
#include "zone-inl.h"
namespace v8 {
namespace internal {
// Scope information represents information about a functions's
// scopes (currently only one, because we don't do any inlining)
// and the allocation of the scope's variables. Scope information
// is stored in a compressed form in FixedArray objects and is used
// at runtime (stack dumps, deoptimization, etc.).
//
// Historical note: In other VMs built by this team, ScopeInfo was
// usually called DebugInfo since the information was used (among
// other things) for on-demand debugging (Self, Smalltalk). However,
// DebugInfo seems misleading, since this information is primarily used
// in debugging-unrelated contexts.
// Forward defined as
// template <class Allocator = FreeStoreAllocationPolicy> class ScopeInfo;
template<class Allocator>
class ScopeInfo BASE_EMBEDDED {
public:
// Create a ScopeInfo instance from a scope.
explicit ScopeInfo(Scope* scope);
// Create a ScopeInfo instance from SerializedScopeInfo.
explicit ScopeInfo(SerializedScopeInfo* data);
// Creates a SerializedScopeInfo holding the serialized scope info.
Handle<SerializedScopeInfo> Serialize();
// --------------------------------------------------------------------------
// Lookup
Handle<String> function_name() const { return function_name_; }
Handle<String> parameter_name(int i) const { return parameters_[i]; }
int number_of_parameters() const { return parameters_.length(); }
Handle<String> stack_slot_name(int i) const { return stack_slots_[i]; }
int number_of_stack_slots() const { return stack_slots_.length(); }
Handle<String> context_slot_name(int i) const {
return context_slots_[i - Context::MIN_CONTEXT_SLOTS];
}
int number_of_context_slots() const {
int l = context_slots_.length();
return l == 0 ? 0 : l + Context::MIN_CONTEXT_SLOTS;
}
Handle<String> LocalName(int i) const;
int NumberOfLocals() const;
// --------------------------------------------------------------------------
// Debugging support
#ifdef DEBUG
void Print();
#endif
private:
Handle<String> function_name_;
bool calls_eval_;
List<Handle<String>, Allocator > parameters_;
List<Handle<String>, Allocator > stack_slots_;
List<Handle<String>, Allocator > context_slots_;
List<Variable::Mode, Allocator > context_modes_;
};
// This object provides quick access to scope info details for runtime
// routines w/o the need to explicitly create a ScopeInfo object.
class SerializedScopeInfo : public FixedArray {
public :
static SerializedScopeInfo* cast(Object* object) {
ASSERT(object->IsFixedArray());
return reinterpret_cast<SerializedScopeInfo*>(object);
}
// Does this scope call eval?
bool CallsEval();
// Does this scope have an arguments shadow?
bool HasArgumentsShadow() {
return StackSlotIndex(GetHeap()->arguments_shadow_symbol()) >= 0;
}
// Return the number of stack slots for code.
int NumberOfStackSlots();
// Return the number of context slots for code.
int NumberOfContextSlots();
// Return if this has context slots besides MIN_CONTEXT_SLOTS;
bool HasHeapAllocatedLocals();
// Lookup support for serialized scope info. Returns the
// the stack slot index for a given slot name if the slot is
// present; otherwise returns a value < 0. The name must be a symbol
// (canonicalized).
int StackSlotIndex(String* name);
// Lookup support for serialized scope info. Returns the
// context slot index for a given slot name if the slot is present; otherwise
// returns a value < 0. The name must be a symbol (canonicalized).
// If the slot is present and mode != NULL, sets *mode to the corresponding
// mode for that variable.
int ContextSlotIndex(String* name, Variable::Mode* mode);
// Lookup support for serialized scope info. Returns the
// parameter index for a given parameter name if the parameter is present;
// otherwise returns a value < 0. The name must be a symbol (canonicalized).
int ParameterIndex(String* name);
// Lookup support for serialized scope info. Returns the
// function context slot index if the function name is present (named
// function expressions, only), otherwise returns a value < 0. The name
// must be a symbol (canonicalized).
int FunctionContextSlotIndex(String* name);
static Handle<SerializedScopeInfo> Create(Scope* scope);
// Serializes empty scope info.
static SerializedScopeInfo* Empty();
private:
inline Object** ContextEntriesAddr();
inline Object** ParameterEntriesAddr();
inline Object** StackSlotEntriesAddr();
};
// Cache for mapping (data, property name) into context slot index.
// The cache contains both positive and negative results.
// Slot index equals -1 means the property is absent.
// Cleared at startup and prior to mark sweep collection.
class ContextSlotCache {
public:
// Lookup context slot index for (data, name).
// If absent, kNotFound is returned.
int Lookup(Object* data,
String* name,
Variable::Mode* mode);
// Update an element in the cache.
void Update(Object* data,
String* name,
Variable::Mode mode,
int slot_index);
// Clear the cache.
void Clear();
static const int kNotFound = -2;
private:
ContextSlotCache() {
for (int i = 0; i < kLength; ++i) {
keys_[i].data = NULL;
keys_[i].name = NULL;
values_[i] = kNotFound;
}
}
inline static int Hash(Object* data, String* name);
#ifdef DEBUG
void ValidateEntry(Object* data,
String* name,
Variable::Mode mode,
int slot_index);
#endif
static const int kLength = 256;
struct Key {
Object* data;
String* name;
};
struct Value {
Value(Variable::Mode mode, int index) {
ASSERT(ModeField::is_valid(mode));
ASSERT(IndexField::is_valid(index));
value_ = ModeField::encode(mode) | IndexField::encode(index);
ASSERT(mode == this->mode());
ASSERT(index == this->index());
}
explicit inline Value(uint32_t value) : value_(value) {}
uint32_t raw() { return value_; }
Variable::Mode mode() { return ModeField::decode(value_); }
int index() { return IndexField::decode(value_); }
// Bit fields in value_ (type, shift, size). Must be public so the
// constants can be embedded in generated code.
class ModeField: public BitField<Variable::Mode, 0, 3> {};
class IndexField: public BitField<int, 3, 32-3> {};
private:
uint32_t value_;
};
Key keys_[kLength];
uint32_t values_[kLength];
friend class Isolate;
DISALLOW_COPY_AND_ASSIGN(ContextSlotCache);
};
} } // namespace v8::internal
#endif // V8_SCOPEINFO_H_