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// Copyright 2012 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_INTERFACE_H_
#define V8_INTERFACE_H_
#include "zone-inl.h" // For operator new.
namespace v8 {
namespace internal {
// This class implements the following abstract grammar of interfaces
// (i.e. module types):
// interface ::= UNDETERMINED | VALUE | MODULE(exports)
// exports ::= {name : interface, ...}
// A frozen module type is one that is fully determined. Unification does not
// allow adding additional exports to frozen interfaces.
// Otherwise, unifying modules merges their exports.
// Undetermined types are unification variables that can be unified freely.
class Interface : public ZoneObject {
public:
// ---------------------------------------------------------------------------
// Factory methods.
static Interface* NewValue() {
static Interface value_interface(VALUE + FROZEN); // Cached.
return &value_interface;
}
static Interface* NewUnknown() {
return new Interface(NONE);
}
static Interface* NewModule() {
return new Interface(MODULE);
}
// ---------------------------------------------------------------------------
// Mutators.
// Add a name to the list of exports. If it already exists, unify with
// interface, otherwise insert unless this is closed.
void Add(Handle<String> name, Interface* interface, bool* ok) {
DoAdd(name.location(), name->Hash(), interface, ok);
}
// Unify with another interface. If successful, both interface objects will
// represent the same type, and changes to one are reflected in the other.
void Unify(Interface* that, bool* ok);
// Determine this interface to be a value interface.
void MakeValue(bool* ok) {
*ok = !IsModule();
if (*ok) Chase()->flags_ |= VALUE;
}
// Determine this interface to be a module interface.
void MakeModule(bool* ok) {
*ok = !IsValue();
if (*ok) Chase()->flags_ |= MODULE;
}
// Set associated instance object.
void MakeSingleton(Handle<JSModule> instance, bool* ok) {
*ok = IsModule() && Chase()->instance_.is_null();
if (*ok) Chase()->instance_ = instance;
}
// Do not allow any further refinements, directly or through unification.
void Freeze(bool* ok) {
*ok = IsValue() || IsModule();
if (*ok) Chase()->flags_ |= FROZEN;
}
// ---------------------------------------------------------------------------
// Accessors.
// Check whether this is still a fully undetermined type.
bool IsUnknown() { return Chase()->flags_ == NONE; }
// Check whether this is a value type.
bool IsValue() { return Chase()->flags_ & VALUE; }
// Check whether this is a module type.
bool IsModule() { return Chase()->flags_ & MODULE; }
// Check whether this is closed (i.e. fully determined).
bool IsFrozen() { return Chase()->flags_ & FROZEN; }
Handle<JSModule> Instance() { return Chase()->instance_; }
// Look up an exported name. Returns NULL if not (yet) defined.
Interface* Lookup(Handle<String> name);
// ---------------------------------------------------------------------------
// Iterators.
// Use like:
// for (auto it = interface->iterator(); !it.done(); it.Advance()) {
// ... it.name() ... it.interface() ...
// }
class Iterator {
public:
bool done() const { return entry_ == NULL; }
Handle<String> name() const {
ASSERT(!done());
return Handle<String>(*static_cast<String**>(entry_->key));
}
Interface* interface() const {
ASSERT(!done());
return static_cast<Interface*>(entry_->value);
}
void Advance() { entry_ = exports_->Next(entry_); }
private:
friend class Interface;
explicit Iterator(const ZoneHashMap* exports)
: exports_(exports), entry_(exports ? exports->Start() : NULL) {}
const ZoneHashMap* exports_;
ZoneHashMap::Entry* entry_;
};
Iterator iterator() const { return Iterator(this->exports_); }
// ---------------------------------------------------------------------------
// Debugging.
#ifdef DEBUG
void Print(int n = 0); // n = indentation; n < 0 => don't print recursively
#endif
// ---------------------------------------------------------------------------
// Implementation.
private:
enum Flags { // All flags are monotonic
NONE = 0,
VALUE = 1, // This type describes a value
MODULE = 2, // This type describes a module
FROZEN = 4 // This type is fully determined
};
int flags_;
Interface* forward_; // Unification link
ZoneHashMap* exports_; // Module exports and their types (allocated lazily)
Handle<JSModule> instance_;
explicit Interface(int flags)
: flags_(flags),
forward_(NULL),
exports_(NULL) {
#ifdef DEBUG
if (FLAG_print_interface_details)
PrintF("# Creating %p\n", static_cast<void*>(this));
#endif
}
Interface* Chase() {
Interface* result = this;
while (result->forward_ != NULL) result = result->forward_;
if (result != this) forward_ = result; // On-the-fly path compression.
return result;
}
void DoAdd(void* name, uint32_t hash, Interface* interface, bool* ok);
void DoUnify(Interface* that, bool* ok);
};
} } // namespace v8::internal
#endif // V8_INTERFACE_H_
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