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}
Simply call InitializeForOfStatement (split out from InitializeForEachStatement)
instead, which already has all the necessary logic.
As part of this, trade one bool arg (is_destructuring) for an int
(iterable_pos).
Review URL: https://codereview.chromium.org/1740293002
Cr-Commit-Position: refs/heads/master@{#34561}
Now there is just one kind, corresponding to what was called "initial" before.
Replacement for "suspend": when the parser sees a yield in JS code, it
will turn it into a Yield node but wrap its argument in an iterator result
object. Replacement for "final": the parser simply inserts a return statement
instead.
R=littledan@chromium.org, mstarzinger@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1751613004
Cr-Commit-Position: refs/heads/master@{#34515}
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}
Runtime asserts are were previously a bit annoying to debug, due to
the lack of a useful error message, even in debug mode. This patch
prints out some more information in debug mode for runtime assert
failures while preserving their exception-throwing semantics. While
we're at it, it requires a semicolon after RUNTIME_ASSERT macro
invocations.
```
$ rlwrap out/Debug/d8 --allow-natives-syntax
V8 version 5.1.0 (candidate)
d8> %ArrayBufferNeuter(1)
#
# Runtime error in ../../src/runtime/runtime-typedarray.cc, line 52
#
# args[0]->IsJSArrayBuffer()
==== C stack trace ===============================
1: 0xf70ab5
2: 0xadeebf
3: 0xadedd4
4: 0x2ef17630693b
(d8):1: illegal access
%ArrayBufferNeuter(1)
^
d8>
```
Also give the other 'illegal access' case (a special SyntaxError type) a more
descriptive error message for its sole usage.
R=adamk
Review URL: https://codereview.chromium.org/1748183002
Cr-Commit-Position: refs/heads/master@{#34401}
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}
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}
of non-pattern expressions, according to the (internally circulated)
design document. Details to be provided here.
1. RewritableAssignmentExpression has been renamed to RewritableExpression.
It is a wrapper for AST nodes that wait for some potential rewriting
(that may or may not happen). Also, Is... and As... macros now see
through RewritableExpressions.
2. The function state keeps a list of rewritable expressions that must be
rewritten only if they are used as non-pattern expressions.
3. Expression classifiers are now templates, parameterized by parser
traits. They keep some additional state: a pointer to the list of
non-pattern rewritable expressions. It is important that expression
classifiers be used strictly in a stack fashion, from now on.
4. The RewriteNonPattern function has been simplified.
BUG=chromium:579913
LOG=N
Committed: https://crrev.com/7f5c864a6faf2b957b7273891e143b9bde35487c
Cr-Commit-Position: refs/heads/master@{#34154}
Review URL: https://codereview.chromium.org/1702063002
Cr-Commit-Position: refs/heads/master@{#34162}
Reason for revert:
[Sheriff] This makes jsfunfuzz unhappy:
https://build.chromium.org/p/client.v8/builders/V8%20Fuzzer/builds/7681
Original issue's description:
> This patch implements an alternative approach to the rewriting
> of non-pattern expressions, according to the (internally circulated)
> design document. Details to be provided here.
>
> 1. RewritableAssignmentExpression has been renamed to RewritableExpression.
> It is a wrapper for AST nodes that wait for some potential rewriting
> (that may or may not happen). Also, Is... and As... macros now see
> through RewritableExpressions.
>
> 2. The function state keeps a list of rewritable expressions that must be
> rewritten only if they are used as non-pattern expressions.
>
> 3. Expression classifiers are now templates, parameterized by parser
> traits. They keep some additional state: a pointer to the list of
> non-pattern rewritable expressions. It is important that expression
> classifiers be used strictly in a stack fashion, from now on.
>
> 4. The RewriteNonPattern function has been simplified.
>
> BUG=chromium:579913
> LOG=N
>
> Committed: https://crrev.com/7f5c864a6faf2b957b7273891e143b9bde35487c
> Cr-Commit-Position: refs/heads/master@{#34154}
TBR=rossberg@chromium.org,bmeurer@chromium.org,titzer@chromium.org,nikolaos@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:579913
Review URL: https://codereview.chromium.org/1712203002
Cr-Commit-Position: refs/heads/master@{#34158}
of non-pattern expressions, according to the (internally circulated)
design document. Details to be provided here.
1. RewritableAssignmentExpression has been renamed to RewritableExpression.
It is a wrapper for AST nodes that wait for some potential rewriting
(that may or may not happen). Also, Is... and As... macros now see
through RewritableExpressions.
2. The function state keeps a list of rewritable expressions that must be
rewritten only if they are used as non-pattern expressions.
3. Expression classifiers are now templates, parameterized by parser
traits. They keep some additional state: a pointer to the list of
non-pattern rewritable expressions. It is important that expression
classifiers be used strictly in a stack fashion, from now on.
4. The RewriteNonPattern function has been simplified.
BUG=chromium:579913
LOG=N
Review URL: https://codereview.chromium.org/1702063002
Cr-Commit-Position: refs/heads/master@{#34154}
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}
This frees up one bit in FunctionKind, which I plan to make slightly
more syntactic info about functions available in SharedFunctionInfo
(needed for ES2015 Function.name support).
BUG=v8:3956, v8:4760
LOG=n
Review URL: https://codereview.chromium.org/1704223002
Cr-Commit-Position: refs/heads/master@{#34125}
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}
This CL adds a TRACE_EVENT where there is an isolated LOG, a HistogramTimer
or a TimerEvent.
Once we have a d8 tracing controller, all TimerEvents will be removed since
they do not provide an added value over TRACE_EVENTs. HistogramTimers will
remain, but their functionality will be limited to Histograms only.
BUG=v8:4562
LOG=N
Review URL: https://codereview.chromium.org/1707563002
Cr-Commit-Position: refs/heads/master@{#34099}
This avoids spending lots of time in Scope::RemoveUnresolved for very long
variable declaration lists.
BUG=v8:4699
LOG=n
Review URL: https://codereview.chromium.org/1655313003
Cr-Commit-Position: refs/heads/master@{#34047}
Instead of doing a full function body traversal we collect return expressions and mark them after function parsing.
And since we rewrite do-expressions so that the result is explicitly assigned to a result variable the statements marking will never hit so I removed it from the AST.
BUG=v8:4698
LOG=N
Review URL: https://codereview.chromium.org/1693523002
Cr-Commit-Position: refs/heads/master@{#33911}
Replace the somewhat awkward RestParamAccessStub, which would always
call into the runtime anyway with a proper FastNewRestParameterStub,
which is basically based on the code that was already there for strict
arguments object materialization. But for rest parameters we could
optimize even further (leading to 8-10x improvements for functions with
rest parameters), by fixing the internal formal parameter count:
Every SharedFunctionInfo has a formal_parameter_count field, which
specifies the number of formal parameters, and is used to decide whether
we need to create an arguments adaptor frame when calling a function
(i.e. if there's a mismatch between the actual and expected parameters).
Previously the formal_parameter_count included the rest parameter, which
was sort of unfortunate, as that meant that calling a function with only
the non-rest parameters still required an arguments adaptor (plus some
other oddities). Now with this CL we fix, so that we do no longer
include the rest parameter in that count. Thereby checking for rest
parameters is very efficient, as we only need to check whether there is
an arguments adaptor frame, and if not create an empty array, otherwise
check whether the arguments adaptor frame has more parameters than
specified by the formal_parameter_count.
The FastNewRestParameterStub is written in a way that it can be directly
used by Ignition as well, and with some tweaks to the TurboFan backends
and the CodeStubAssembler, we should be able to rewrite it as
TurboFanCodeStub in the near future.
Drive-by-fix: Refactor and unify the CreateArgumentsType which was
different in TurboFan and Ignition; now we have a single enum class
which is used in both TurboFan and Ignition.
R=jarin@chromium.org, rmcilroy@chromium.orgTBR=rossberg@chromium.org
BUG=v8:2159
LOG=n
Review URL: https://codereview.chromium.org/1676883002
Cr-Commit-Position: refs/heads/master@{#33809}
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}
Also various related cleanup in ParseVariableDeclarations(). The only
changes in logic are explained below:
- We were redundantly checking for parenthesized binding patterns;
these are already ruled out by BindingPatternUnexpectedToken()
calls in the places where we hit an LPAREN.
- There's no need to default-initialize a LET-mode variable in a
for-each loop, just as there isn't for CONST or CONST_LEGACY
(ParseForStatement will take care of properly initializing all
of the above).
Review URL: https://codereview.chromium.org/1661193002
Cr-Commit-Position: refs/heads/master@{#33749}
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 CL deals with yield* by desugaring it in the parser. Hence the
full-codegen implementation of it becomes obsolete and can be removed in a
future CL.
The only change in semantics should be that the results of the iterator's next
and throw methods are checked to be objects, which didn't happen before but is
required by the spec.
BUG=
Review URL: https://codereview.chromium.org/1643903003
Cr-Commit-Position: refs/heads/master@{#33735}
This patch adds a UseCounter for each of the following:
- Allowing duplicate sloppy-mode block-scoped function declarations
in the exact same scope
- for-in loops with an initializer
The patch also refactors some of the declaration code to clean it up and
enable the first counter, and adds additional unit tests to nail down
the semantics of edge cases of sloppy-mode block-scoped function declarations.
BUG=v8:4693,chromium:579395
LOG=N
R=adamk
Review URL: https://codereview.chromium.org/1633743003
Cr-Commit-Position: refs/heads/master@{#33650}
A class's name is its constructor's name, so there's no need to treat it separately,
either in the parser or in code generation. The main parser use of the name is
for ES2015 Function.name handling, and this patch also cleans up handling there
by adding a new IsAnonymousFunctionDefinition() method to Expression (the name
comes from the spec).
Also removed unused ParserTraits::DefaultConstructor method.
BUG=v8:3699
LOG=n
Review URL: https://codereview.chromium.org/1647213002
Cr-Commit-Position: refs/heads/master@{#33643}
NonPatternRewrite was called more than once for the same AST
in the case of (computed) key expressions present in object
literals. As an example, in:
var x = { [[...42]]: 17 };
the array containing the spread would be desugared first and
then the resulting do-expression would again be desugared.
This could be problematic if a computed key expression contains
large nested array/object literals.
R=rossberg@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1645023002
Cr-Commit-Position: refs/heads/master@{#33632}
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}
In a generator function, the parser rewrites a return statement into a "final"
yield. A final yield used to close the generator, which was incorrect because
the return may occur inside a try-finally clause and so the generator may not
yet terminate.
BUG=
Review URL: https://codereview.chromium.org/1634553002
Cr-Commit-Position: refs/heads/master@{#33537}
This CL implements PrepareForTailCall() mentioned in ES6 spec for full codegen, Crankshaft and Turbofan.
When debugger is active tail calls are disabled.
Tail calling can be enabled by --harmony-tailcalls flag.
BUG=v8:4698
LOG=Y
TBR=rossberg@chromium.org
Review URL: https://codereview.chromium.org/1609893003
Cr-Commit-Position: refs/heads/master@{#33509}
The web appears to depend on being able to redeclare functions-in-blocks
in sloppy mode (examples seen so far tend to redeclare identical functions,
most likely accidentally).
This patch opens a minimal hole: two same-named function declarations
in the same scope are allowed, only in sloppy mode.
BUG=v8:4693, chromium:579395
LOG=y
Review URL: https://codereview.chromium.org/1622723003
Cr-Commit-Position: refs/heads/master@{#33478}
Although the `for..in` statement allows Expressions to define the
iterator, only an AssignmentExpression may occupy this position in the
`for..of` statement.
BUG=v8:4692
LOG=N
R=adamk@chromium.org
Review URL: https://codereview.chromium.org/1602823003
Cr-Commit-Position: refs/heads/master@{#33420}
This may have made more sense in the old module design (where
"unification" was a thing), but as-is it's only used for a few
asserts in debug mode. These asserts don't make much sense inside
ModuleDescriptor; instead, as the modules implementation is fleshed
out, I expect the appropriate replacement asserts to show up at the
use of the ModuleDescriptor.
Review URL: https://codereview.chromium.org/1598433006
Cr-Commit-Position: refs/heads/master@{#33345}
This includes anonymous Function, Generator, and Class declarations when
preceded by 'export default'. Parsing only at the moment, nothing useful is
done with the parsed Function/ClassLiteral.
BUG=v8:1569
LOG=n
Review URL: https://codereview.chromium.org/1589173002
Cr-Commit-Position: refs/heads/master@{#33344}
When derived constructors return a non-object (or not undefined) we
currently throw an exception directly in the callee context. This was
achieved by desugaring the return statement for derived classes. To
be spec compliamnt a separate ConstructStubForDerived is introduced.
Instead of trowing directly, the desugared return statement inside
a derived constructor only returns an integer to indicate an incompatible
result.
BUG=v8:4509
LOG=n
Review URL: https://codereview.chromium.org/1593553002
Cr-Commit-Position: refs/heads/master@{#33336}
This avoids manual, fragile assignment to Parser::scope_. And once all such
assignments are removed, BlockState might become much more valuable as
a place to reset scope-related state.
Also remove unnecessary nullptr checks after calls to FinalizeBlockScope.
Review URL: https://codereview.chromium.org/1583453003
Cr-Commit-Position: refs/heads/master@{#33313}
This avoids generating different scopes on the two compilation passes, which
results in various delirious side-effects.
There's some cleanup to be done in lazy arrow function parsing, but I'd
rather do that in a separate patch, with this one targeted at fixing the
particular crash.
BUG=chromium:572589
LOG=n
Review URL: https://codereview.chromium.org/1575333004
Cr-Commit-Position: refs/heads/master@{#33311}
In short, array literals containing spreads, when used as expressions,
are rewritten using do expressions. E.g.
[1, 2, 3, ...x, 4, ...y, 5]
is roughly rewritten as:
do {
$R = [1, 2, 3];
for ($i of x) %AppendElement($R, $i);
%AppendElement($R, 4);
for ($j of y) %AppendElement($R, $j);
%AppendElement($R, 5);
$R
}
where $R, $i and $j are fresh temporary variables.
R=rossberg@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1564083002
Cr-Commit-Position: refs/heads/master@{#33307}
This patch implements eager expression rewriting when parsing. It will
be used for desugaring spreads but may have other uses in the future.
We call Traits::RewriteExpression as soon as we realise that something
parsed as an expression is actually used as an expression (and not as
a pattern). This patch adds a dummy implementation for this function,
doing no rewriting at all, and adds the trigers in the right places of
the parser.
R=rossberg@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1567603005
Cr-Commit-Position: refs/heads/master@{#33300}
