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}
Reason for revert:
[Sheriff] Breaks gc stress:
https://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20gc%20stress/builds/1642
Original issue's description:
> [es7] refactor and fix Object.values() / Object.entries()
>
> 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.
>
> BUG=v8:4663
> LOG=N
> R=adamk@chromium.org, rossberg@chromium.org, littledan@chromium.org
>
> Committed: https://crrev.com/5c5ccd9d7f8693990d1a9eb26ba3a94f376dcf0b
> Cr-Commit-Position: refs/heads/master@{#33782}
TBR=littledan@chromium.org,adamk@chromium.org,cbruni@chromium.org,rossberg@chromium.org,caitpotter88@gmail.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4663
Review URL: https://codereview.chromium.org/1675663002
Cr-Commit-Position: refs/heads/master@{#33787}
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.
BUG=v8:4663
LOG=N
R=adamk@chromium.org, rossberg@chromium.org, littledan@chromium.org
Review URL: https://codereview.chromium.org/1637753004
Cr-Commit-Position: refs/heads/master@{#33782}
Adds a new runtime function, %DefineDataPropertyInLiteral, which
takes a fifth argument specifying whether the property and value
are syntactically such that the value is a function (or class)
literal that should have its name set at runtime.
The new runtime call also allows us to eliminate the now-redundant
%DefineClassMethod runtime function.
This should get much less ugly once we can desugar the "dynamic"
part of object literals in the parser (but that work is currently
blocked on having a performant way of desugaring literals).
BUG=v8:3699, v8:3761
LOG=n
Review URL: https://codereview.chromium.org/1626423003
Cr-Commit-Position: refs/heads/master@{#33756}
Note: This is currently only used by yield*, we still need to support it in
other places (such as for-of loops). It can be used manually of course.
(This CL does not touch the full-codegen implementation of yield* because that
code is already dead. The yield* desugaring already supports return and doesn't
need to be touched.)
BUG=v8:3566
LOG=y
Review URL: https://codereview.chromium.org/1639343005
Cr-Commit-Position: refs/heads/master@{#33744}
This removes --harmony-completion, --harmony-concat-spreadable, and
--harmony-tolength and moves the appropriate tests from harmony/ to es6/.
Review URL: https://codereview.chromium.org/1667453002
Cr-Commit-Position: refs/heads/master@{#33712}
Reason for revert:
This test fails:
assertEquals(["as"], /^a[\u017F]/ui.exec("as"));
The reason is that we end up with a character class that is not stand alone, so we do not perform case folding on it correctly (with unicode flag).
Original issue's description:
> [regexp] implement /ui to mirror the implementation for /i.
>
> R=erik.corry@gmail.com, erikcorry@chromium.org
>
> Committed: https://crrev.com/eea1a4c003c559c99bcc9f08aa7eadf931975aad
> Cr-Commit-Position: refs/heads/master@{#33655}
TBR=erik.corry@gmail.com,erikcorry@chromium.org,erikcorry@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
Review URL: https://codereview.chromium.org/1661483002
Cr-Commit-Position: refs/heads/master@{#33676}
ES2015 Annex B.1.4 specifies a restricted pattern language for unicode
mode. This change reflects that, based on some test262 test cases.
R=littledan@chromium.org
BUG=v8:2952
LOG=N
Review URL: https://codereview.chromium.org/1645573002
Cr-Commit-Position: refs/heads/master@{#33584}
The body of a generator function can now refer to the generator's input value via a new
"function.sent" expression. We extend the proposal at
https://github.com/allenwb/ESideas/blob/master/Generator%20metaproperty.md
in the obvious way to also apply to GeneratorResumeAbrupt.
This will enable us to desugar yield*.
The new syntax is behind a new --harmony-function-sent flag.
BUG=v8:4700
LOG=n
Review URL: https://codereview.chromium.org/1620253003
Cr-Commit-Position: refs/heads/master@{#33574}
Note that in these cases, we don't support computed property names yet, just
as we don't for object and class literals.
BUG=v8:3699, v8:4710
LOG=n
Review URL: https://codereview.chromium.org/1634403002
Cr-Commit-Position: refs/heads/master@{#33562}
This patch makes Array.prototype.concat support subclassing Arrays
and constructing instances properly with Symbol.species. It is
guarded by the --harmony-species flag.
R=cbruni
LOG=Y
BUG=v8:4093
Review URL: https://codereview.chromium.org/1577043002
Cr-Commit-Position: refs/heads/master@{#33503}
Cleanup %ForInPrepare runtime entry, and unify common logic with
%ForInEnumerate (renamed from %GetPropertyNamesFast). Also introduce
a TupleType to properly type JSForInPrepare and its projections w/o
special hacks in the Typer. And fix %ForInNext and JSForInNext to be
consistent with fullcodegen again (after the proxy refactorings last
quarter).
R=jarin@chromium.org
BUG=v8:3650
LOG=n
Review URL: https://codereview.chromium.org/1631583002
Cr-Commit-Position: refs/heads/master@{#33487}
