The spec was modified to relax some requirements which implementors had not been
enforcing. Part of this process involved introducing a new abstract operation
ToIndex, which had partial overlap with our existing semantics as well as some
differences (most notably treating undefined as 0). Test262 tests were introduced to
check for the new semantics, some of which we were failing. This patch amends the
parts of our implementation corresponding to specification algorithms which use
ToIndex to follow its semantics precisely.
BUG=v8:4784,v8:5120
Review-Url: https://codereview.chromium.org/2090353003
Cr-Commit-Position: refs/heads/master@{#37406}
Add a flag harmony_trailing_commas_in_parameters that allows trailing
commas in function parameter declaration lists and function call
parameter lists. Trailing commas are allowed in parenthetical lists like
`(a, b, c,)` only if the next token is `=>`, thereby making it an arrow
function declaration. Only 1 trailing comma is allowed, not `(a,,)`. A
trailing comma must follow a non-rest parameter, so `(,)` and `(...a,)`
are still SyntaxErrors. However, a trailing comma is allowed after a
spread parameter, e.g. `a(...b,);`.
Add parser tests for all of the above.
BUG=v8:5051
LOG=y
Review-Url: https://codereview.chromium.org/2094463002
Cr-Commit-Position: refs/heads/master@{#37355}
When calling the throw method on a generator suspended inside a yield*, yield*
in turn tries to call throw on its iterable. If the iterable does not provide a
throw method, yield* must try to call the return method instead and then throw a
TypeError. Due to a bug in our desugaring, we never threw the TypeError.
R=adamk@chromium.org
BUG=v8:5132
Review-Url: https://codereview.chromium.org/2094253002
Cr-Commit-Position: refs/heads/master@{#37314}
When calling the return method on a generator suspended inside a yield*, yield*
in turn calls return on its iterable. If this results in a "done" iterator,
yield* must return immediately, thus terminating the generator. For some
reason, we didn't terminate the generator but continued right after the yield*.
R=adamk@chromium.org
BUG=v8:5131
Review-Url: https://codereview.chromium.org/2100093002
Cr-Commit-Position: refs/heads/master@{#37310}
Named capture groups may be specified using the /(?<name>pattern)/u
syntax, with named backreferences specified as /\k<name>/u. They're
hidden behind the --harmony-regexp-named-captures flag, and are only
enabled for unicode regexps.
R=yangguo@chromium.org
BUG=
Review-Url: https://codereview.chromium.org/2050343002
Cr-Commit-Position: refs/heads/master@{#36986}
This patch adds a test for async/await analogous to a previous Promise test.
It also fixes a typo in promise.js and makes a previous Promise test more
correct by ensuring that all assertions run before completion, fixing the
test expectations for the real result (which seems correct).
BUG=v8:4483
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_chromium_rel_ng;tryserver.blink:linux_blink_rel
Review-Url: https://codereview.chromium.org/2037653002
Cr-Commit-Position: refs/heads/master@{#36903}
Async functions are built out of generators, but the
SharedFunctionInfo returns false for is_generator. is_resumable is
the broader query. This patch fixes many parts of V8 to refer
to is_resumable as appropriate.
One incidental change is to remove a check for generators extending
classes. This is part of a general check for constructors being the
only thing which can extend classes, so it is removed here and the
error message for the general case is made more accurate.
BUG=v8:4483
Review-Url: https://codereview.chromium.org/1996943002
Cr-Commit-Position: refs/heads/master@{#36621}
Annex B 3.3 applies only for ordinary FunctionDeclarations, not
GeneratorDeclarations or AsyncFunctionDeclarations. This patch
- Skips applying Annex B 3.3 to async functions
- Adds a flag to refrain from applying it to generators
- UseCounter for how often duplicate function in block occurs
with generators (unclear how to measure need for hoisting from block)
BUG=v8:4806
Review-Url: https://codereview.chromium.org/1995863002
Cr-Commit-Position: refs/heads/master@{#36557}
Duplicate mjsunit/harmony/generators.js but explicitly require
--turbo-from-bytecode such that Clusterfuzz can thoroughly test the
new generators implementation.
BUG=v8:4907
Review-Url: https://codereview.chromium.org/2002983002
Cr-Commit-Position: refs/heads/master@{#36441}
This adds back the instanceof operator support in the backends and
introduces a @@hasInstance protector cell on the isolate that guards the
fast path for the InstanceOfStub. This way we recover the ~10%
regression on Octane EarleyBoyer in Crankshaft and greatly improve
TurboFan and Ignition performance of instanceof.
R=ishell@chromium.orgTBR=hpayer@chromium.org,rossberg@chromium.org
BUG=chromium:597249, v8:4447
LOG=n
Review-Url: https://codereview.chromium.org/1980483003
Cr-Commit-Position: refs/heads/master@{#36275}
Currently we do not check for @@isConcatSpreadable properly. If the Symbol is
set on the Array.prototype or Object.prototype the current fast paths fail.
This CL adds a fix to globally invalidate a isConcatSpreadable_protector.
Drive-by-fix: use named accessors for context variables
LOG=N
BUG=chromium:542504, v8:903
Review-Url: https://codereview.chromium.org/1409123003
Cr-Commit-Position: refs/heads/master@{#36201}
In the bytecode graphbuilder, translate the two generator-specific
bytecodes as a couple of runtime calls for now.
BUG=v8:4907
LOG=n
Review-Url: https://codereview.chromium.org/1957393004
Cr-Commit-Position: refs/heads/master@{#36134}
Previously, the species protector was invalidated whenever the __proto__ of
an Array instance was manipulated. Then, if the map's new_target_is_base field
remained set, it was correct to conclude that GetPrototypeOf(array) was
%ArrayPrototype%. However, this choice caused the popular D3 framework to
invalidate the species protector, causing many functions to become slower.
This patch eliminates that aspect of the species protector. Instead, the check
is to look at the instance->map()->prototype(). It is valid to look directly
at the map's prototype slot, ignoring hidden prototypes and proxies, because
- This is only called on Array instances, so the receiver cannot be a Proxy.
- For hidden prototypes, any inaccuracy would only result in conservatively
taking the slow path.
Theoretically, this patch could make methods applied to arrays from other
contexts slower. However, the slowdown would only affect a particular array
instance and not have a global spill-over effect. Further, the slowdown could
be addressed by tracking, either in the instance's map or in the actual
prototype object, whether it is a %ArrayPrototype% from any context, in a way
which is cheap to query, and use that rather than comparing to the currently
executing native context.
In interactive testing, this patch led the OnShape CAD system to experience
faster load times (110+s -> 40s).
BUG=chromium:606207
LOG=Y
Review-Url: https://codereview.chromium.org/1936393002
Cr-Commit-Position: refs/heads/master@{#36033}
Return the empty string from StringPad if the filler argument is the empty
string, effectively returning the string unchanged in StringPadStart and
StringPadEnd.
```
"foo".padStart(100000, "") -> "foo"
```
BUG=v8:4957, v8:4954
LOG=N
R=littledan@chromium.org
Review-Url: https://codereview.chromium.org/1926773003
Cr-Commit-Position: refs/heads/master@{#35837}
This is necessary to eventually build a turbofan graph.
BUG=v8:4907
LOG=n
Review URL: https://codereview.chromium.org/1901713003
Cr-Commit-Position: refs/heads/master@{#35820}
The feature was deprecated in M49 and flagged off in M50.
This patch removes it entirely from the codebase.
Review URL: https://codereview.chromium.org/1909433003
Cr-Commit-Position: refs/heads/master@{#35714}
This patch correctly re-scopes inner scopes that can appear in do
expressions used as initializers to arrow parameters.
R=rossberg@chromium.org
BUG=v8:4904
LOG=N
Review URL: https://codereview.chromium.org/1887743002
Cr-Commit-Position: refs/heads/master@{#35542}
Reland of (https://codereview.chromium.org/1617503003)
* New atomic code stubs for x64, ia32, arm, arm64
* Add convenience functions JumpIfNotValidSmiValue, JumpIfUintNotValidSmiValue
to macro-assembler-ia32 (API based on x64 macro assembler)
* Remove runtime implementation of Atomics.load, the code stub should always be
called instead
* Add new test to mjsunit atomics test; check that Smi values of different
sizes are supported when possible, else fall back to HeapNumbers
These changes were needed to add another codestub:
* Bump kStubMajorKeyBits from 7 to 8
* Reduce ScriptContextFieldStub::kSlotIndexBits from 13 to 12
BUG=v8:4614
LOG=y
TBR=jarin@chromium.org,bmeurer@chromium.org,rodolph.perfetta@gmail.com,machenbach@chromium.org
Review URL: https://codereview.chromium.org/1617503003
Cr-Commit-Position: refs/heads/master@{#35427}
Review URL: https://codereview.chromium.org/1881383003
Cr-Commit-Position: refs/heads/master@{#35453}
Reason for revert:
[Sheriff] Roll was reverted. Please fix unused methods, see:
https://codereview.chromium.org/1884913002/https://build.chromium.org/p/tryserver.chromium.win/builders/win_clang/builds/5585/steps/compile%20%28with%20patch%29/logs/stdio
Original issue's description:
> [Atomics] code stubs for atomic operations
>
> * New atomic code stubs for x64, ia32, arm, arm64
> * Add convenience functions JumpIfNotValidSmiValue, JumpIfUintNotValidSmiValue
> to macro-assembler-ia32 (API based on x64 macro assembler)
> * Remove runtime implementation of Atomics.load, the code stub should always be
> called instead
> * Add new test to mjsunit atomics test; check that Smi values of different
> sizes are supported when possible, else fall back to HeapNumbers
>
> These changes were needed to add another codestub:
> * Bump kStubMajorKeyBits from 7 to 8
> * Reduce ScriptContextFieldStub::kSlotIndexBits from 13 to 12
>
> BUG=v8:4614
> LOG=y
>
> Committed: https://crrev.com/10b5febe11b318cfef130abae343183ac862e60d
> Cr-Commit-Position: refs/heads/master@{#35427}
TBR=jarin@chromium.org,bmeurer@chromium.org,rodolph.perfetta@gmail.com,binji@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4614
Review URL: https://codereview.chromium.org/1884883003
Cr-Commit-Position: refs/heads/master@{#35443}
* New atomic code stubs for x64, ia32, arm, arm64
* Add convenience functions JumpIfNotValidSmiValue, JumpIfUintNotValidSmiValue
to macro-assembler-ia32 (API based on x64 macro assembler)
* Remove runtime implementation of Atomics.load, the code stub should always be
called instead
* Add new test to mjsunit atomics test; check that Smi values of different
sizes are supported when possible, else fall back to HeapNumbers
These changes were needed to add another codestub:
* Bump kStubMajorKeyBits from 7 to 8
* Reduce ScriptContextFieldStub::kSlotIndexBits from 13 to 12
BUG=v8:4614
LOG=y
Review URL: https://codereview.chromium.org/1617503003
Cr-Commit-Position: refs/heads/master@{#35427}
Add support for optimizing objects with elements, which do not invoke JS and
cannot change the shape of the Object.
BUG=v8:4663
LOG=N
Review URL: https://codereview.chromium.org/1767113004
Cr-Commit-Position: refs/heads/master@{#35081}
It's been on since M49. Also moved tests from harmony -> es6,
one of which was merged with another test of the same name.
While moving stuff over to regexp.js, I also noticed that there
were unused calls to %FunctionSetName and %SetNativeFlag (those
calls are already handled by InstallGetter()).
Review URL: https://codereview.chromium.org/1838563003
Cr-Commit-Position: refs/heads/master@{#35076}
This patch implements ES2015 RegExp subclassing semantics, namely the
hardest part where RegExp.prototype.exec and certain flag getters can
be overridden in order to provide different behavior. This change is
hidden behind a new flag, --harmony-regexp-exec. The flag guards the
behavior by installing entirely different implementations of the
methods which follow the new semantics.
Preliminary performance tests show a 3-4x regression in the Octane
RegExp benchmark. The new code doesn't call out into several fast
paths that the old code supported, so this is expected.
The patch is tested mostly by test262, where most RegExp tests are fixed,
with the exception of deliberate spec violations for web compatibility,
and for the 'sticky' flag, which is not dynamically read by this patch
in all cases but rather statically compiled into the RegExp. The latter
will require a follow-on patch to implement. A small additional set of
tests verifies one particular case, mostly to check whether the flag
mechanism works.
R=adamk,yangguo@chromium.org
LOG=Y
BUG=v8:4602
Review URL: https://codereview.chromium.org/1596483005
Cr-Commit-Position: refs/heads/master@{#35068}
Now that ES2015 const has shipped, in Chrome 49, legacy const declarations
are no more. This lets us remove a bunch of code from many parts of the
codebase.
In this patch, I remove parser support for generating legacy const variables
from const declarations. This also removes the special "illegal declaration"
bit from Scope, which has ripples into all compiler backends.
Also gone are any tests which relied on legacy const declarations.
Note that we do still generate a Variable in mode CONST_LEGACY in one case:
function name bindings in sloppy mode. The likely fix there is to add a new
Variable::Kind for this case and handle it appropriately for stores in each
backend, but I leave that for a later patch to make this one completely
subtractive.
Review URL: https://codereview.chromium.org/1819123002
Cr-Commit-Position: refs/heads/master@{#35002}
Both of them shipped in Chrome 49 without incident.
Also move relevant tests from harmony/ to es6/.
Review URL: https://codereview.chromium.org/1815773002
Cr-Commit-Position: refs/heads/master@{#34964}
The way desugared instanceof called OrdinaryHasInstance if the lookup of
@@hasInstance failed was incorrect.
BUG=v8:4774
LOG=N
Review URL: https://codereview.chromium.org/1812793002
Cr-Commit-Position: refs/heads/master@{#34855}
Modules already have a separate entrypoint into the engine (at the moment,
this is v8::ScriptCompiler::CompileModule, though that will change to
something like ParseModule). This meant that requiring a commandline flag
simply added an extra complexity burden on embedders. By removing the v8
flag, this lets embedders use their own flagging mechanism (such as d8's
"--module", or Blink's RuntimeEnabledFeatures) to control whether
modules are to be used.
Also remove old modules tests that were being skipped (since they test
very old, pre-ES2015 modules syntax).
R=littledan@chromium.org
BUG=v8:1569, chromium:594639
LOG=y
Review URL: https://codereview.chromium.org/1804693002
Cr-Commit-Position: refs/heads/master@{#34764}
ES2015 Object.prototype.toString semantics were enabled in version 4.9,
which has been in stable Chrome for nearly two weeks at this point.
R=littledan@chromium.org
Review URL: https://codereview.chromium.org/1784033002
Cr-Commit-Position: refs/heads/master@{#34732}
These flags have been on by default since version 4.9, which has been
in stable Chrome for over a week now, demonstrating that they're
here to stay.
Also moved the tests out of harmony/ and into es6/.
Review URL: https://codereview.chromium.org/1776683003
Cr-Commit-Position: refs/heads/master@{#34692}
We must close the iterator whenever the destructuring didn't exhaust it, unless an iterator operation (eg. next) threw. We do this by wrapping the iterator use in a try-catch-finally similar to the desugaring of for-of.
This is behind --harmony-iterator-close.
R=adamk@chromium.org
BUG=v8:3566
LOG=Y
Review URL: https://codereview.chromium.org/1772793002
Cr-Commit-Position: refs/heads/master@{#34654}
The initial species protector hooked into property declaration in an
incomplete place, and missed definitions of accessors. This patch repairs
them by calling out to update the protector from an additional location.
R=adamk
CC=verwaest,cbruni
BUG=v8:4093
LOG=Y
Review URL: https://codereview.chromium.org/1746323002
Cr-Commit-Position: refs/heads/master@{#34599}
ES2015 generally bans FunctionDeclarations in positions which expect a Statement,
as opposed to a StatementListItem, such as a FunctionDeclaration which constitutes
the body of a for loop. However, Annex B 3.2 and 3.4 make exceptions for labeled
function declarations and function declarations as the body of an if statement in
sloppy mode, in the latter case specifying that the semantics are as if the
function declaration occurred in a block. Chrome has historically permitted
further extensions, for the body of any flow control construct.
This patch addresses both the syntactic and semantic mismatches between V8 and
the spec. For the semantic mismatch, function declarations as the body of if
statements change from unconditionally hoisting in certain cases to acquiring
the sloppy mode function in block semantics (based on Annex B 3.3). For the
extra syntax permitted, this patch adds a flag,
--harmony-restrictive-declarations, which excludes disallowed function declaration
cases. A new UseCounter, LegacyFunctionDeclaration, is added to count how often
function declarations occur as the body of other constructs in sloppy mode. With
this patch, the code generally follows the form of the specification with respect
to parsing FunctionDeclarations, rather than allowing them in arbitrary Statement
positions, and makes it more clear where our extensions occur.
BUG=v8:4647
R=adamk
LOG=Y
Review URL: https://codereview.chromium.org/1757543003
Cr-Commit-Position: refs/heads/master@{#34470}
We used to emit debug break location on block entry. This cannot be
ported to the interpreted as we do not emit bytecode for block entry.
This made no sense to begin with though, but accidentally added
break locations for var declarations.
With this change, the debugger no longer breaks at var declarations
without initialization. This is in accordance with the fact that the
interpreter does not emit bytecode for uninitialized var declarations.
Also fix the bytecode to match full-codegen's behavior wrt return
positions:
- there is a break location before the return statement, with the source
position of the return statement.
- right before the actual return, there is another break location. The
source position points to the end of the function.
R=rmcilroy@chromium.org, vogelheim@chromium.orgTBR=rossberg@chromium.org
BUG=v8:4690
LOG=N
Review URL: https://codereview.chromium.org/1744123003
Cr-Commit-Position: refs/heads/master@{#34388}
The for-of-finalization CL incorrectly removed the input argument from
BuildIteratorClose. I'm reverting this, adding a regression test, and fixing an
existing test that was wrong.
BUG=
R=rossberg
Review URL: https://codereview.chromium.org/1750543002
Cr-Commit-Position: refs/heads/master@{#34384}
This patch moves iterator finalization (calling .return() when a
for-of loop exits early) to shipping. The only part of this feature
which is currently known to be missing is destructuring--.return()
should be also be called when destructuring with an array which
does not end in a rest pattern, but it currently does not. The rest
of this feature, including calling .return() from certain builtins,
is implemented.
R=adamk
BUG=v8:3566
LOG=Y
Review URL: https://codereview.chromium.org/1738463003
Cr-Commit-Position: refs/heads/master@{#34307}
There was a bug in for-of loops without newly declared variables: If,
in performing the assignment, an exception were thrown, then
IteratorClose would not be called. The problem was that the assignment
is done as part of assign_each, which happens before the loop is put
back in the state which is recognized to be breaking/throwing/returning
early.
This patch modifies the for-of desugaring by setting the loop state
before, rather than after, evaluating the assign_each portion, which is
responsible for evaluating the assignment in for-of loops which do not
have a declaration.
This patch, together with https://codereview.chromium.org/1728973002 ,
allow all test262 iterator return-related tests to pass.
R=rossberg
BUG=v8:4776
LOG=Y
Review URL: https://codereview.chromium.org/1731773003
Cr-Commit-Position: refs/heads/master@{#34262}
In the for-of desugaring, IteratorClose is a subtle thing to get right.
When return exists, the logic for which exception to throw is as follows:
1. Get the 'return' property and property any exception that might come from
the property read
2. Call return, not yet propagating an exception if it's thrown.
3. If we are closing the iterator due to an exception, propagate that error.
4. If return threw, propagate that error.
5. Check if return's return value was not an object, and throw if so
Previously, we were effectively doing step 5 even if an exception "had already
been thrown" by step 3. Because this took place in a finally block, the exception
"won the race" and was the one propagated to the user. The fix is a simple change
to the desugaring to do step 5 only if step 3 didn't happen.
R=rossberg
BUG=v8:4775
LOG=Y
Review URL: https://codereview.chromium.org/1728973002
Cr-Commit-Position: refs/heads/master@{#34261}
This implements proper handling of local control flow (i.e. break and
continue) that spans the boundary of a do-expression. We can no longer
determine the number of operands to be dropped from the nesting of
statements alone, instead we use the new precise operand stack depth
tracking.
R=jarin@chromium.org
TEST=mjsunit/harmony/do-expressions-control
BUG=v8:4488
LOG=n
Review URL: https://codereview.chromium.org/1724753002
Cr-Commit-Position: refs/heads/master@{#34246}
This implements a mechanism to track the exact depth of the operand
stack in full-codegen for every sub-expression visitation. So far we
only tracked the depth at statement level, but not at expression level.
With the introduction of do-expressions it will be possible to construct
local control flow (i.e. break, continue and friends) that target labels
at an arbitrary operand stack depth, making this tracking a prerequisite
for full do-expression support.
R=rossberg@chromium.org,jarin@chromium.org
BUG=v8:4755,v8:4488
LOG=n
Review URL: https://codereview.chromium.org/1706283002
Cr-Commit-Position: refs/heads/master@{#34211}
In ES2016, the Proxy enumerate trap is removed. This patch changes
for-in iteration on Proxies to use the ownKeys trap. Due to the clean
organization of that code, the patch basically consists of deletions.
R=adamk
LOG=Y
BUG=v8:4768
Review URL: https://codereview.chromium.org/1717893002
Cr-Commit-Position: refs/heads/master@{#34200}
This patch makes ArraySpeciesCreate fast in V8 by avoiding two property reads
when the following conditions are met:
- No Array instance has had its __proto__ reset
- No Array instance has had a constructor property defined
- Array.prototype has not had its constructor changed
- Array[Symbol.species] has not been reset
For subclasses of Array, or for conditions where one of these assumptions is
violated, the full lookup of species is done according to the ArraySpeciesCreate
algorithm. Although this is a "performance cliff", it does not come up in the
expected typical use case of @@species (Array subclassing), so it is hoped that
this can form a good start. Array subclasses will incur the slowness of looking
up @@species, but their use won't slow down invocations of, for example,
Array.prototype.slice on Array base class instances.
Possible future optimizations:
- For the fallback case where the assumptions don't hold, optimize the two
property lookups.
- For Array.prototype.slice and Array.prototype.splice, even if the full lookup
of @@species needs to take place, we still could take the rest of the C++
fastpath. However, to do this correctly requires changing the calling convention
from C++ to JS to pass the @@species out, so it is not attempted in this patch.
With this patch, microbenchmarks of Array.prototype.slice do not suffer a
noticeable performance regression, unlike their previous 2.5x penalty.
TBR=hpayer@chromium.org
Review URL: https://codereview.chromium.org/1689733002
Cr-Commit-Position: refs/heads/master@{#34199}
The Proxy enumerate trap and Reflect.enumerate are removed from the
ES2016 draft specification. This patch removes the Reflect.enumerate
function, and a follow-on patch will be responsible for the Proxy
trap changes.
R=adamk
LOG=Y
BUG=v8:4768
Review URL: https://codereview.chromium.org/1721453002
Cr-Commit-Position: refs/heads/master@{#34196}
Various syntactic forms now cause functions to have names where they
didn't before. Per the upcoming changes to the toString spec, only
a name that was literally part of a function's expression or declaration
is meant to be reflected in toString. This also happens to be the same
set of names that V8 currently outputs (without the --harmony-function-name
flag).
This required distinguishing anonymous FunctionExpressions from other sorts
of function definitions (like methods and getters/setters) in the AST, parser,
and at runtime.
The patch also takes the opportunity to remove one more argument (and enum)
from FunctionLiteral, as well as adding a special factory method for the
case of a FunctionLiteral representing toplevel or eval'd code.
BUG=v8:4760
LOG=n
Review URL: https://codereview.chromium.org/1712833002
Cr-Commit-Position: refs/heads/master@{#34132}
Implements iterator finalisation by desugaring for-of loops with an additional try-finally wrapper. See comment in parser.cc for details.
Also improved some AST printing facilities while there.
@Ross, I had to disable the bytecode generation test for for-of, because it got completely out of hand after this change (the new bytecode has 150+ lines). See the TODO that I assigned to you.
Patch set 1 is WIP patch by Georg (http://crrev.com/1695583003), patch set 2 relative changes.
@Georg, FYI, I changed the following:
- Moved try-finally out of the loop body, for performance, and in order to be able to handle `continue` correctly.
- Fixed scope management in ParseForStatement, which was the cause for the variable allocation failure.
- Fixed pre-existing zone initialisation bug in rewriter, which caused the crashes.
- Enabled all tests, adjusted a few others, added a couple more.
BUG=v8:2214
LOG=Y
Review URL: https://codereview.chromium.org/1695393003
Cr-Commit-Position: refs/heads/master@{#34111}
When doing advance at the start of an unanchored unicode regexp,
we do not have to care about surrogate pairs. If we actually advance
into the middle of a surrogate pair, the only choice is to also
consume trail surrogate as nothing else can match from there.
This reduces the emitted code slightly. By not having choice in the
loop, we do not have to push backtrack onto the stack, preventing
stack overflow.
R=erik.corry@gmail.com, erikcorry@chromium.org
Review URL: https://codereview.chromium.org/1676293003
Cr-Commit-Position: refs/heads/master@{#33838}
Previously, Object.values() and Object.entries() were piggy-backing on
Object.keys(). This meant that they would pre-filter non-enumerable properties,
violating the runtime behaviour of the methods. Unfortunately, this does not
match the current proposal text.
Also incorporates several tests verifying this behaviour based on tests included
in the ChakraCore implementation.
In this reland, the new patch fills up the longer-lasting FixedArray with
`undefined` to avoid the crash in Heap::Verify().
Originally reviewed at https://codereview.chromium.org/1637753004
BUG=v8:4663
LOG=N
R=adamk@chromium.org, rossberg@chromium.org, littledan@chromium.org
Review URL: https://codereview.chromium.org/1673673002
Cr-Commit-Position: refs/heads/master@{#33818}
