f3a22f965e
code. By the time we optimize the code, we'll be able to decide on new or old space based on the number of surviving objects after one or more gcs. The mechanism is a "memento" placed behind objects in the heap. It's currently done for array and object literals, with plans to use mementos for constructed objects as well (in a later CL). The feature is behind the flag allocation_site_pretenuring, currently off. R=hpayer@chromium.org Review URL: https://codereview.chromium.org/40063002 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18104 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
125 lines
4.3 KiB
C++
125 lines
4.3 KiB
C++
// Copyright 2013 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef V8_ALLOCATION_SITE_SCOPES_H_
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#define V8_ALLOCATION_SITE_SCOPES_H_
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#include "ast.h"
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#include "handles.h"
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#include "objects.h"
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#include "zone.h"
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namespace v8 {
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namespace internal {
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// AllocationSiteContext is the base class for walking and copying a nested
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// boilerplate with AllocationSite and AllocationMemento support.
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class AllocationSiteContext {
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public:
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explicit AllocationSiteContext(Isolate* isolate) {
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isolate_ = isolate;
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};
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Handle<AllocationSite> top() { return top_; }
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Handle<AllocationSite> current() { return current_; }
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bool ShouldCreateMemento(Handle<JSObject> object) { return false; }
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Isolate* isolate() { return isolate_; }
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protected:
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void update_current_site(AllocationSite* site) {
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*(current_.location()) = site;
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}
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void InitializeTraversal(Handle<AllocationSite> site) {
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top_ = site;
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current_ = Handle<AllocationSite>(*top_, isolate());
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}
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private:
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Isolate* isolate_;
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Handle<AllocationSite> top_;
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Handle<AllocationSite> current_;
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};
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// AllocationSiteCreationContext aids in the creation of AllocationSites to
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// accompany object literals.
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class AllocationSiteCreationContext : public AllocationSiteContext {
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public:
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explicit AllocationSiteCreationContext(Isolate* isolate)
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: AllocationSiteContext(isolate) { }
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Handle<AllocationSite> EnterNewScope();
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void ExitScope(Handle<AllocationSite> site, Handle<JSObject> object);
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};
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// AllocationSiteUsageContext aids in the creation of AllocationMementos placed
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// behind some/all components of a copied object literal.
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class AllocationSiteUsageContext : public AllocationSiteContext {
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public:
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AllocationSiteUsageContext(Isolate* isolate, Handle<AllocationSite> site,
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bool activated)
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: AllocationSiteContext(isolate),
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top_site_(site),
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activated_(activated) { }
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inline Handle<AllocationSite> EnterNewScope() {
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if (top().is_null()) {
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InitializeTraversal(top_site_);
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} else {
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// Advance current site
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Object* nested_site = current()->nested_site();
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// Something is wrong if we advance to the end of the list here.
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ASSERT(nested_site->IsAllocationSite());
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update_current_site(AllocationSite::cast(nested_site));
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}
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return Handle<AllocationSite>(*current(), isolate());
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}
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inline void ExitScope(Handle<AllocationSite> scope_site,
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Handle<JSObject> object) {
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// This assert ensures that we are pointing at the right sub-object in a
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// recursive walk of a nested literal.
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ASSERT(object.is_null() || *object == scope_site->transition_info());
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}
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bool ShouldCreateMemento(Handle<JSObject> object);
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private:
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Handle<AllocationSite> top_site_;
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bool activated_;
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};
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} } // namespace v8::internal
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#endif // V8_ALLOCATION_SITE_SCOPES_H_
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