v8/src/preparse-data-format.h
marja@chromium.org 98cd283399 Remove symbol preparse data altogether.
Removing it seems to be a clear win on mobile: producing symbol data makes cold
parsing 20-30% slower, and having symbol data doesn't make warm parsing any
faster.

Notes:
- V8 used to produce symbol data, but because of a bug, it was never used until
recently. (See fix https://codereview.chromium.org/172753002 which takes the
symbol data into use again.)
- On desktop, warm parsing is faster if we have symbol data, and producing it
during cold parsing doesn't make parsing substantially slower. However, this
doesn't seem to be the case on mobile.
- The preparse data (cached data) will now contain only the positions of the
lazy functions.

BUG=
R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/261273003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@21146 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2014-05-05 14:55:13 +00:00

40 lines
1.2 KiB
C++

// Copyright 2011 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_PREPARSE_DATA_FORMAT_H_
#define V8_PREPARSE_DATA_FORMAT_H_
namespace v8 {
namespace internal {
// Generic and general data used by preparse data recorders and readers.
struct PreparseDataConstants {
public:
// Layout and constants of the preparse data exchange format.
static const unsigned kMagicNumber = 0xBadDead;
static const unsigned kCurrentVersion = 9;
static const int kMagicOffset = 0;
static const int kVersionOffset = 1;
static const int kHasErrorOffset = 2;
static const int kFunctionsSizeOffset = 3;
static const int kSizeOffset = 4;
static const int kHeaderSize = 5;
// If encoding a message, the following positions are fixed.
static const int kMessageStartPos = 0;
static const int kMessageEndPos = 1;
static const int kMessageArgCountPos = 2;
static const int kIsReferenceErrorPos = 3;
static const int kMessageTextPos = 4;
static const unsigned char kNumberTerminator = 0x80u;
};
} } // namespace v8::internal.
#endif // V8_PREPARSE_DATA_FORMAT_H_