v8/src/compilation-cache.h
kasperl@chromium.org b5a72a1645 Generalized the EvalCache into a CompilationCache and enabled
it for scripts too. In the context of Chromium, this should 
have a very positive impact on memory consumption for web apps
that run multiple tabs from the same domain with a lot of the
same JavaScript code.

For now, the cache retirement policy is really simple:
Whenever a mark-sweep collection is started we clear the
cache. This guarantees that this change will not have a
huge negative impact on memory consumption, but it may
not be ideal. We should consider a more sophisticated LRU
scheme.
Review URL: http://codereview.chromium.org/1933

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@270 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2008-09-11 10:51:52 +00:00

86 lines
3.6 KiB
C++

// Copyright 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_COMPILATION_CACHE_H_
#define V8_COMPILATION_CACHE_H_
namespace v8 { namespace internal {
// The compilation cache keeps function boilerplates for compiled
// scripts and evals. The boilerplates are looked up using the source
// string as the key.
class CompilationCache {
public:
// The same source code string has different compiled code for
// scripts and evals. Internally, we use separate caches to avoid
// getting the wrong kind of entry when looking up.
enum Entry {
SCRIPT,
EVAL_GLOBAL,
EVAL_CONTEXTUAL
};
// Finds the script function boilerplate for a source
// string. Returns an empty handle if the cache doesn't contain a
// script for the given source string with the right origin.
static Handle<JSFunction> LookupScript(Handle<String> source,
Handle<Object> name,
int line_offset,
int column_offset);
// Finds the function boilerplate for a source string for
// eval. Returns an empty handle if the cache doesn't contain a
// script for the given source string.
static Handle<JSFunction> LookupEval(Handle<String> source,
Entry entry);
// Associate the (source, kind) pair to the boilerplate. This may
// overwrite an existing mapping.
static void Associate(Handle<String> source,
Entry entry,
Handle<JSFunction> boilerplate);
// Clear the cache - also used to initialize the cache at startup.
static void Clear();
// GC support.
static void Iterate(ObjectVisitor* v);
// Notify the cache that a mark-sweep garbage collection is about to
// take place. This is used to retire entries from the cache to
// avoid keeping them alive too long without using them. For now, we
// just clear the cache but we should consider are more
// sophisticated LRU scheme.
static void MarkCompactPrologue() { Clear(); }
};
} } // namespace v8::internal
#endif // V8_COMPILATION_CACHE_H_