Yak shaving for map sharing with accessor properties contd.: When CALLBACKS can
have map transitions, simply looking at the property type is not sufficient
anymore to decide if a property is there or not. One has to look at the actual
contents of the descriptor entry then, but this breaks down sometimes when the
lookup is being done with a NULL holder. Luckily enough, we can oftren replace
IsProperty by the simpler IsFound, because we inspect the type immediately
afterwards, anyway.
Review URL: https://chromiumcodereview.appspot.com/9280007
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10474 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The main goal is to cleanly separate between the several parts involved in the traversal:
* iterating over all transitions in a descriptor array
* iterating over all prototype transitions
* storing the parent and the current local traversal position in a map
* the iterative traversal algorithm itself
The previous algorithm for iterating over prototype transitions did a little bit too much here, iterating over the whole array instead only the filled part. This has been fixed on the way, too.
With this CL, it will be much easier to make the necessary changes to the descriptor array iterator to correctly handle map transitions for accessor properties. Furthermore, perhaps we represent transitions a bit different in the future, making finding them a bit easier. This would make some code in this CL (and elsewhere) quite a bit shorter and more efficient.
Review URL: https://chromiumcodereview.appspot.com/9252007
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10473 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Loosen the requirement for Map equivalency on several map checks, including checks up the prototype chain, that are not sensitive to ElementsKinds. These selected map checks should also match against FAST_DOUBLE_ELEMENT and FAST_ELEMENT transitions of the original map. This specifically helps all variants of transitioned JSArrays to still efficiently call builtins like push, pop and sort.
BUG=none
TEST=none
Committed: http://code.google.com/p/v8/source/detail?r=10331
Review URL: http://codereview.chromium.org/9015020
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10356 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
CPU-eating DOS attacks against node.js servers. Based on code from
Bert Belder. This version only solves the issue for those that compile
V8 themselves or those that do not use snapshots. A snapshot-based
precompiled V8 will still have predictable string hash codes.
Review URL: http://codereview.chromium.org/9086006
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10330 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This fixes how Object.defineProperty() defines JavaScript accessors on
objects with installed API interceptors. The definition itself does not
cause any interceptors to be called, whereas any subsequent accesses on
said object will still fire the interceptor. This behavior is in sync
with API accessors.
R=rossberg@chromium.org
BUG=v8:1651,chromium:94666
TEST=cctest/test-api
Review URL: http://codereview.chromium.org/9021019
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10293 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This introduces an additional check into the StoreIC_ArrayLength builtin
checking that the array still has fast properties. Redifinitions of the
length property that would cause it's type or attributes to change, will
switch to slow properties, thereby invalidating said optimization.
R=svenpanne@chromium.org
BUG=v8:1756
TEST=test262
Review URL: http://codereview.chromium.org/8895025
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10254 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This CL introduces a third mode next to the non-strict
(henceforth called 'classic mode') and 'strict mode'
which is called 'extended mode' as in the current
ES.next specification drafts. The extended mode is based on
the 'strict mode' and adds new functionality to it. This
means that most of the semantics of these two modes
coincide.
The 'extended mode' is entered instead of the 'strict mode'
during parsing when using the 'strict mode' directive
"use strict" and when the the harmony-scoping flag is
active. This should be changed once it is fully specified how the 'extended mode' is entered.
This change introduces a new 3 valued enum LanguageMode
(see globals.h) corresponding to the modes which is mostly
used by the frontend code. This includes the following
components:
* (Pre)Parser
* Compiler
* SharedFunctionInfo, Scope and ScopeInfo
* runtime functions: StoreContextSlot,
ResolvePossiblyDirectEval, InitializeVarGlobal,
DeclareGlobals
The old enum StrictModeFlag is still used in the backend
when the distinction between the 'strict mode' and the 'extended mode' does not matter. This includes:
* SetProperty runtime function, Delete builtin
* StoreIC and KeyedStoreIC
* StubCache
Review URL: http://codereview.chromium.org/8417035
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10062 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Changes the way we do lazy deoptimization:
1. For side-effect instructions, we insert the lazy-deopt call at
the following LLazyBailout instruction.
CALL
GAP
LAZY-BAILOUT ==> lazy-deopt-call
2. For other instructions (StackCheck) we insert it right after the
instruction since the deopt targets an earlier deoptimization environment.
STACK-CHECK
GAP ==> lazy-deopt-call
The pc of the lazy-deopt call that will be patched in is recorded in the
deoptimization input data. Each Lithium instruction can have 0..n safepoints.
All safepoints get the deoptimization index of the associated LAZY-BAILOUT
instruction. On lazy deoptimization we use the return-pc to find the safepoint.
The safepoint tells us the deoptimization index, which in turn finds us the
PC where to insert the lazy-deopt-call.
Additional changes:
* RegExpLiteral marked it as having side-effects so that it
gets an explicitlazy-bailout instruction (instead of
treating it specially like stack-checks)
* Enable target recording CallFunctionStub to achieve
more inlining on optimized code.
BUG=v8:1789
TEST=jslint and uglify run without crashing, mjsunit/compiler/regress-lazy-deopt.js
Review URL: http://codereview.chromium.org/8492004
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10006 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Each such string requires small amount of heap memory.
Heap snapshot generator copies all the strings into internal hash map for future use.
The each copy requires much more memory than original v8 string.
I made a workaround for this. The snapshot will copy only first 1024 symbols.
A simple drive-by fix was made for a performance problem in ToCString implementation.
BUG=v8:1816
TEST=none
Review URL: http://codereview.chromium.org/8509003
Patch from Ilya Tikhonovsky <loislo@chromium.org>.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9928 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This also refactors the way we set the length of an arrays' backing
store to use the new elements accessor interface. The actual fix is in
DictionaryElementsAccessor::SetLengthWithoutNormalize() where we first
search for non-deletable elements according to ES5 section 15.4.5.2
specifications.
Snippet from the specification: Attempting to set the length property of
an Array object to a value that is numerically less than or equal to the
largest numeric property name of an existing array indexed non-deletable
property of the array will result in the length being set to a numeric
value that is one greater than that largest numeric property name.
R=danno@chromium.org
TEST=test262/15.4.4.??-7-b-16
Review URL: http://codereview.chromium.org/8372064
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9911 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Do not rely on 'default' clauses or 'if's when analysing a PropertyType, because
this makes it hard to find the relevant places when a new type is added. Note
that the detection of "phantom property types" is left untouched, because this
might have a performance impact, especially for the GC (to be investigated).
This is a preliminary step for introducing a new kind of map transition.
Review URL: http://codereview.chromium.org/8491016
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9900 ce2b1a6d-e550-0410-aec6-3dcde31c8c00