Here is a description of the background and design of split window in Chrome and V8:
https://docs.google.com/a/google.com/Doc?id=chhjkpg_47fwddxbfr
This change list splits the window object into two parts: 1) an inner window object used as the global object of contexts; 2) an outer window object exposed to JavaScript and accessible by the name 'window'. Firefox did it awhile ago, here are some discussions: https://wiki.mozilla.org/Gecko:SplitWindow. One additional benefit of splitting window in Chrome is that accessing global variables don't need security checks anymore, it can improve applications that use many global variables.
V8 support of split window:
There are a small number of changes on V8 api to support split window:
Security context is removed from V8, so does related API functions;
A global object can be detached from its context and reused by a new context;
Access checks on an object template can be turned on/off by default;
An object can turn on its access checks later;
V8 has a new object type, ApiGlobalObject, which is the outer window object type. The existing JSGlobalObject becomes the inner window object type. Security checks are moved from JSGlobalObject to ApiGlobalObject. ApiGlobalObject is the one exposed to JavaScript, it is accessible through Context::Global(). ApiGlobalObject's prototype is set to JSGlobalObject so that property lookups are forwarded to JSGlobalObject. ApiGlobalObject forwards all other property access requests to JSGlobalObject, such as SetProperty, DeleteProperty, etc.
Security token is moved to a global context, and ApiGlobalObject has a reference to its global context. JSGlobalObject has a reference to its global context as well. When accessing properties on a global object in JavaScript, the domain security check is performed by comparing the security token of the lexical context (Top::global_context()) to the token of global object's context. The check is only needed when the receiver is a window object, such as 'window.document'. Accessing global variables, such as 'var foo = 3; foo' does not need checks because the receiver is the inner window object.
When an outer window is detached from its global context (when a frame navigates away from a page), it is completely detached from the inner window. A new context is created for the new page, and the outer global object is reused. At this point, the access check on the DOMWindow wrapper of the old context is turned on. The code in old context is still able to access DOMWindow properties, but it has to go through domain security checks.
It is debatable on how to implement the outer window object. Currently each property access function has to check if the receiver is ApiGlobalObject type. This approach might be error-prone that one may forget to check the receiver when adding new functions. It is unlikely a performance issue because accessing global variables are more common than 'window.foo' style coding.
I am still working on the ARM port, and I'd like to hear comments and suggestions on the best way to support it in V8.
Review URL: http://codereview.chromium.org/7366
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underlying string representation of the two strings involved.
- Renamed ascii and two byte string classes to sequential ascii and
sequential two byte, and renamed IsAscii and friends to
IsAsciiRepresentation. This is to make a clear distinction between
strings with an ascii/two-byte representation, of which there is
four, and flat sequential ascii/two-byte string.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@474 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
ExtendStorage did not work with keyed store IC.
- Reduced instructions generated when performing a tail call to
kSharedStoreIC_ExtendStorage
- Moved test/mjsunit/bugs/bug-109.js
to test/mjsunit/keyed-storage-extend.js
Review URL: http://codereview.chromium.org/6526
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instances->set(i, *GetScriptWrapper(script));
GetScriptWrapper can call GC. The failure have only been seen on ARM, where
the g++ compiler pulls out the object from the instances handle to a register
before calling GetScriptWrapper causing set to be called on an object which
may have moved.
Marked a test on ARM as no longer flaky, whereas two other fails consistently
but that is no longer related to the problem fixed above.
BUG=1308895
Review URL: http://codereview.chromium.org/6271
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are always odd if the bit-field bits are included.
Modified a couple of debugger tests that relied on the ordering of
elements in descriptor arrays. Descriptor arrays are sorted by
hash-code values, so the order changes if we change the hash code.
Review URL: http://codereview.chromium.org/6489
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@440 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
All uses of %AddProperty are replaced by %SetProperty. A few uses of
IgnoreAttributesAndSetLocalProperty are added, and the runtime version
of it adds a PropertyAttributes argument. Only the JSObject class
in objects.cc now uses AddProperty, and it can become private.
Review URL: http://codereview.chromium.org/6445
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are evaluated with an extra element on the stack, which needs
to be taken into account when breaking and continuing.
I'll clean up the code and add an abstraction for manipulating
the break stack height in a future CL -- I want to try to get
rid of the separate local variable we keep around for the "state"
when running in a finally block.
Review URL: http://codereview.chromium.org/5625
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upper case. Moved it into the RelocInfo class together with the associated
is_xxx functions. Renamed is_xxx to IsXxx in the process.
Removed the exit_js_frame mode as it was no longer used.
Patch Set 2 renames RELOC_MODE_COUNT to NUMBER_OF_MODES and fixes a couple of lint errors.
Review URL: http://codereview.chromium.org/3186
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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
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exceptions.
It turned out that the stack overflow fix from before had disabled
message storing in another test. Previously, stack overflows would
actually cause a message object to start being created but cause
another exception which would not be reported and that's what stopped
the infinite regress. This change resores that behavior.
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* Make old_data_space non-executable on OSs and hardware that support it.
* Rename old_space to old_pointer_space (can contain pointers, esp. to new space).
* Ensure that individual pages allocated for old_space are only executable when
they are for code objects.
* Ensure Space::Setup can cope with non-aligned memory.
* Make some methods on Spaces virtual. Make a way to iterate over all spaces.
* Replace executability flag with Executability enum in order to make intent at
call site clearer.
* Fix serialization/deserialization to allocate write barrier memory for large
arrays.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@165 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
of the case where ENV is not a dictionary which could happen when the
environment variable ENV was set when invoking SCons.
Fixed building dynamic library on Windows in the case where env overrides was
specified as before these was not passed to the linking of the DLL.
There is still a SCons issue when the environment variable ENV is set when
invoking SCons, however this looks like a SCons issue.
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- Added option to test runner that allows us to run the tests under
valgrind.
- Added test status for the failing arm simulator tests.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@116 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
__ pop(eax);
...
__ push(eax);
to enable push/pop eliminations.
__ push(eax) must happen before RecordWrite because RecordWrite may destroy
eax value. To be safe, also moved __ push(r0) on ARM to above RecordWrite.
This only affects the case where a context variable is used in a inner scope.
Create a tests for it. It fails if __ push(eax) is after RecordWrite.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@111 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
to fail on Windows.
Updated mozilla.status to use correct syntax for tests that are
allowed to fail in debug mode.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@97 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
temporary storage for moving data from register xmm0 to st(0) instead of overwriting
the parameters. This fixes a test that crashed on Windows in release build due to
stack corruption.
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while V8 is running.
A debugger using the V8 message based interface now needs to control the
call to DebugBreak in order for the messages send to be processed. Commands can
still be send when V8 is not in a break, but they will not be processed until
there is a break. The response "request queued" when queuing up messages have
been removed. This gets rid of a non JSON message being used.
Modified the threaded debugger tests to call DebugBreak instead of relying
on it occouring automatically.
This change will not be committed until the outstanding Chrome change
http://chrome-reviews.prom.corp.google.com/2072 (which updates Chrome to control
the DebugBreak call) have been reviewed and committed.
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now responsible for adding the status information for the tests in the
corresponding test suite.
Added status file from mjsunit tests.
Added tests for known bugs.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@29 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
- Fixed mozilla test breakage caused by python's obscure module
loading rules.
- Made sure test.py propagates test failures out as the exit code of
the script.
- Remove runtime calls to get number constants. Remove Heap roots for
some special numbers.
- Fix typo in accessors.h.
- Changes CopyMap to not copy descriptors. Adds
CopyMapRemoveTransitions that copies non-transition descriptors.
Changes interface of DescriptorArray::Copy operations to simplify
them.
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Added better test support.
Added load, quit and version functions to the shell sample so it's easier to run benchmarks and tests.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
In the shell sample don't print the result of executing a script, only
evaluating expressions.
Fixed issue when building samples on Windows using a shared V8
library. Added visibility option on Linux build which makes the
generated library 18% smaller.
Changed build system to accept multiple build modes in one build and
generate seperate objects, libraries and executables for each mode.
Removed deferred negation optimization (a * -b => -(a * b)) since this
visibly changes operand conversion order.
Improved parsing performance by introducing stack guard in preparsing.
Without a stack guard preparsing always bails out with stack overflow.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Extended the shell sample with a --runtime-flags option.
Added Visual Studio project files for the shell.cc and process.cc samples.
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