This removes RegExpPrototypeSpeciesGetter and IteratorPrototypeIterator and
uses ReturnReceiver builtin instead.
This patch also ports the PromiseSpecies to TF by reusing this
builtin.
BUG=v8:5343
Review-Url: https://codereview.chromium.org/2590373002
Cr-Commit-Position: refs/heads/master@{#41879}
This moves the platform-specific distinction to one place, and allows
to just include assembler-inl.h instead of macro-assembler.h to get the
correct inline functions defined in assembler.h (e.g.
RelocInfo::set_target_address).
R=mstarzinger@chromium.org, titzer@chromium.org
Review-Url: https://codereview.chromium.org/2587113002
Cr-Commit-Position: refs/heads/master@{#41843}
Use FastAsciiConvert (as used by Unibrow) for i18n-aware
case conversion with --icu_case_mapping.
Move FastAsciiConvert to src/string-case.cc so that it can be used
by both runtime-{string,i18n}.
Add more tests.
BUG=v8:4477,v8:4476
TEST=intl/general/case*
Review-Url: https://codereview.chromium.org/2533983006
Cr-Commit-Position: refs/heads/master@{#41821}
This patch introduces:
1. ICStats class to store ic statistics items produced by V8,
2. A disabled by default tracing category v8.ic_stats,
3. An trace event V8.ICStats that contains ic statistics items in args,
We store ic statistics items in an array until the array is full to reduce
the number of trace events.
TBR=jkummerow@chromium.org,ishell@chromium.org
Review-Url: https://codereview.chromium.org/2503183002
Cr-Commit-Position: refs/heads/master@{#41559}
This CL adds a new header src/debug/interface-types.h, moves the
definition of Location from the debug-interface.h to this new header,
and adds a new definition for the WasmDisassembly types.
This allows to use the types in other implementation files or headers
without having to include the entire debug-interface.h, reducing build
dependencies and compile time (especially for incremental builds).
The WasmDisassembly type replaces the old
std::pair<std::string, std::vector<std::tuple<...>>>, which was a bit
hard to unravel.
R=yangguo@chromium.org, kozyatinskiy@chromium.org, titzer@chromium.org
Review-Url: https://codereview.chromium.org/2529383002
Cr-Commit-Position: refs/heads/master@{#41488}
This allows us to optimise the bytecode liveness analysis to jump
directly to previously seen indices. The analysis is optimised to store
a stack of loop ends (JumpLoop bytecode indices), and iterate through
these indices directly rather than looping through the bytecode array to
find them.
Review-Url: https://codereview.chromium.org/2536653003
Cr-Commit-Position: refs/heads/master@{#41485}
Replaces the graph-based liveness analyzer in the bytecode graph builder
with an initial bytecode-based liveness analysis pass, which is added to
the existing loop extent analysis.
Now the StateValues in the graph have their inputs initialised to
optimized_out, rather than being modified after the graph is built.
Review-Url: https://codereview.chromium.org/2523893003
Cr-Commit-Position: refs/heads/master@{#41355}
Reason for revert:
Breaks the build:
https://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20shared/builds/14886
Original issue's description:
> [ignition/turbo] Perform liveness analysis on the bytecodes
>
> Replaces the graph-based liveness analyzer in the bytecode graph builder
> with an initial bytecode-based liveness analysis pass, which is added to
> the existing loop extent analysis.
>
> Now the StateValues in the graph have their inputs initialised to
> optimized_out, rather than being modified after the graph is built.
>
> Committed: https://crrev.com/1852300954c216c29cf93444430681d213e87925
> Cr-Commit-Position: refs/heads/master@{#41344}
TBR=jarin@chromium.org,rmcilroy@chromium.org,yangguo@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
Review-Url: https://codereview.chromium.org/2541443002
Cr-Commit-Position: refs/heads/master@{#41346}
Replaces the graph-based liveness analyzer in the bytecode graph builder
with an initial bytecode-based liveness analysis pass, which is added to
the existing loop extent analysis.
Now the StateValues in the graph have their inputs initialised to
optimized_out, rather than being modified after the graph is built.
Review-Url: https://codereview.chromium.org/2523893003
Cr-Commit-Position: refs/heads/master@{#41344}
They're supposed to be stable across several parse passes, so we'll also
store them in the associated SharedFunctionInfos
To achieve this, the PreParser and Parser need to generated the same number of
FunctionLiterals. To achieve this, we teach the PreParser about desuggaring of
class literals.
For regular functions, the function IDs are assigned in the order they occur in
the source. For arrow functions, however, we only know that it's an arrow function
after parsing the parameter list, and so the ID assigned to the arrow function is
larger than the IDs assigned to functions defined in the parameter list. This
implies that we have to reset the function ID counter to before the parameter list
when re-parsing an arrow function. To be able to do this, we store the number of
function literals found in the parameter list of arrow functions as well.
BUG=v8:5589
Review-Url: https://codereview.chromium.org/2481163002
Cr-Commit-Position: refs/heads/master@{#41309}
The AstGraphBuilder pipeline is only used for asm.js now, so the whole
type feedback mechanism is essentially dead code currently, thus we
better nuke it.
BUG=v8:5267,v8:5657
Review-Url: https://codereview.chromium.org/2523953002
Cr-Commit-Position: refs/heads/master@{#41201}
Now that we have a JumpLoop bytecode, we can heavily simplify the
branch/loop analysis by assuming that only JumpLoop bytecodes are
backwards edges, and performing the loop analysis as a single
(backwards) pass.
This allows us to get rid of the branch analysis entirely, and builds a
framework to do liveness analysis in the same pass.
Review-Url: https://codereview.chromium.org/2519983002
Cr-Commit-Position: refs/heads/master@{#41194}
The handwritten-assembly implementations of both dispatcher and
generic stub have been replaced by Turbofan-generated stubs.
Review-Url: https://codereview.chromium.org/2523473002
Cr-Commit-Position: refs/heads/master@{#41188}
When disassembling functions for the inspector, we used an internal
text representation before. This CL implements the official text
format like it is understood by the spec interpreter.
Example output:
func $main (param i32) (result i32)
block i32
get_local 0
i32.const 2
i32.lt_u
if
i32.const -2
return
end
get_local 0
call_indirect 0
end
R=rossberg@chromium.org, titzer@chromium.org
BUG=chromium:659715
Review-Url: https://codereview.chromium.org/2520943002
Cr-Commit-Position: refs/heads/master@{#41172}
Instead of directly using v8_enable_inspector_override from
build_overrides/v8.gni in all the GN configs, set a v8_enable_inspector
variable based on v8_enable_inspector_override and use that everywhere.
This is the more common pattern seen in over projects, and reduces the
need to include //build_overrides/v8.gni in many files.
Review-Url: https://codereview.chromium.org/2520683002
Cr-Commit-Position: refs/heads/master@{#41156}
This pre-calculates and stores a vector of bytecode offsets, and then allows
one to iterate over it backwards. This could probably be adapted to a
bidirectional/random access iterator if we wanted to, but for now reverse
is all we need.
Review-Url: https://codereview.chromium.org/2518003002
Cr-Commit-Position: refs/heads/master@{#41153}
Refactors the bytecode array iterator to separate the iteration and the
bytecode parameter access, placing the latter into a separate
super-class. This will allow us to have other forms of access, e.g.
reverse iteration.
Review-Url: https://codereview.chromium.org/2519923002
Cr-Commit-Position: refs/heads/master@{#41152}
In component build, fuzzer did not link with icu libraries, causing
errors. By adding icu libraries to dependencies fuzzer links correctly.
BUG=
TEST=fuzzer/*
Review-Url: https://codereview.chromium.org/2510063002
Cr-Commit-Position: refs/heads/master@{#41098}
The new AccessorAssembler encapsulates all the functionality that's
specific to building LoadIC/StoreIC stubs.
There are two header files (accessor-assembler.h and
accessor-assembler-impl.h) so that clients of the assembler can include
the one, and subclassing assemblers can include the other.
Review-Url: https://codereview.chromium.org/2507733002
Cr-Commit-Position: refs/heads/master@{#41037}
When generating snapshot on a machine with a different page size than
the target machine, we can run into problems as the v8 page area size
changes. This is because v8 has page guards which depend on os page
size, so if the target has larger os page, v8 page area is smaller and
may not fit the contents.
The solution proposed here is adding a flag, v8_os_page_size, that
would, if used, override local os page size and use the one specified
during snapshot generation.
BUG=
Review-Url: https://codereview.chromium.org/2488403003
Cr-Commit-Position: refs/heads/master@{#40997}
SourcePosition::InliningId() refers to a the new table DeoptimizationInputData::InliningPositions(), which provides the following data for every inlining id:
- The inlined SharedFunctionInfo as an offset into DeoptimizationInfo::LiteralArray
- The SourcePosition of the inlining. Recursively, this yields the full inlining stack.
Before the Code object is created, the same information can be found in CompilationInfo::inlined_functions().
If SourcePosition::InliningId() is SourcePosition::kNotInlined, it refers to the outer (non-inlined) function.
So every SourcePosition has full information about its inlining stack, as long as the corresponding Code object is known. The internal represenation of a source position is a positive 64bit integer.
All compilers create now appropriate source positions for inlined functions. In the case of Turbofan, this required using AstGraphBuilderWithPositions for inlined functions too. So this class is now moved to a header file.
At the moment, the additional information in source positions is only used in --trace-deopt and --code-comments. The profiler needs to be updated, at the moment it gets the correct script offsets from the deopt info, but the wrong script id from the reconstructed deopt stack, which can lead to wrong outputs. This should be resolved by making the profiler use the new inlining information for deopts.
I activated the inlined deoptimization tests in test-cpu-profiler.cc for Turbofan, changing them to a case where the deopt stack and the inlining position agree. It is currently still broken for other cases.
The following additional changes were necessary:
- The source position table (internal::SourcePositionTableBuilder etc.) supports now 64bit source positions. Encoding source positions in a single 64bit int together with the difference encoding in the source position table results in very little overhead for the inlining id, since only 12% of the source positions in Octane have a changed inlining id.
- The class HPositionInfo was effectively dead code and is now removed.
- SourcePosition has new printing and information facilities, including computing a full inlining stack.
- I had to rename compiler/source-position.{h,cc} to compiler/compiler-source-position-table.{h,cc} to avoid clashes with the new src/source-position.cc file.
- I wrote the new wrapper PodArray for ByteArray. It is a template working with any POD-type. This is used in DeoptimizationInputData::InliningPositions().
- I removed HInlinedFunctionInfo and HGraph::inlined_function_infos, because they were only used for the now obsolete Crankshaft inlining ids.
- Crankshaft managed a list of inlined functions in Lithium: LChunk::inlined_functions. This is an analog structure to CompilationInfo::inlined_functions. So I removed LChunk::inlined_functions and made Crankshaft use CompilationInfo::inlined_functions instead, because this was necessary to register the offsets into the literal array in a uniform way. This is a safe change because LChunk::inlined_functions has no other uses and the functions in CompilationInfo::inlined_functions have a strictly longer lifespan, being created earlier (in Hydrogen already).
BUG=v8:5432
Review-Url: https://codereview.chromium.org/2451853002
Cr-Commit-Position: refs/heads/master@{#40975}
In component build, unittests did not link with icu libraries, which
caused errors. By adding icu libraries to dependencies unittests links
correctly.
BUG=
TEST=unittests/*
Review-Url: https://codereview.chromium.org/2479863002
Cr-Commit-Position: refs/heads/master@{#40955}
- Creates a new promise-utils.{h, cc} which refactors out the
logic to create resolving functions. This is shared between the
runtime functions and builtins.
- Changes PromiseResolveThenableJobInfo to store the context
since we no longer create the resolving functions in JS.
- Changes EnqueuPromiseResolveThenableJob to take in the promise and
not the callbacks.
BUG=v8:5343
Review-Url: https://codereview.chromium.org/2487053002
Cr-Commit-Position: refs/heads/master@{#40941}
This CL moves all heap-allocated WASM data structures, both ones
that are bonafide JSObjects and ones that are FixedArrays only, into a
consistent place with consistent layout. Note that not all accessors are complete, and I haven't fully spread the new static typing goodness
to all places in the code.
R=ahaas@chromium.org,rossberg@chromium.org
CC=gdeepti@chromium.org,mtrofin@chromium.org,clemensh@chromium.org
BUG=
Review-Url: https://codereview.chromium.org/2490663002
Cr-Commit-Position: refs/heads/master@{#40913}
- A new runtime function (%create_resolving_functions) is installed to
call the CreateResolvingFunctions builtin from JS.
- Three new builtins are created - resolve and reject functions and a
third function that creates a new JSFunctions from these
resolve/reject builtins.
- The promise reject function is installed on the context temporarily
as internal_promise_reject. This should go away once we remove
PromiseSet.
BUG=v8:5343
Review-Url: https://codereview.chromium.org/2459283004
Cr-Commit-Position: refs/heads/master@{#40903}
This patch removes TracingCategoryObserver API and moves the creation of
observer inside platform initialization, by assuming that either
Platform::AddTraceStateObserver is implemented correctly to add observer to
tracing controller that implemented by embedders, or default tracing controller
has already been set up and attached to platform before
v8::V8::InitializePlatform is called.
BUG=v8:5590
Review-Url: https://codereview.chromium.org/2471583004
Cr-Commit-Position: refs/heads/master@{#40739}
This patch implements TracingCategoryObserver to set global flag when a V8
specific category is enabled. Previously, we set a global flag each time when we
encounter a top level trace event, and use it as a global check. With this
patch, we can set a group of flags when tracing is enabled; besides, we make
V8 tracing feature use V8 flags instead of defining its own flag in a messy way.
With this patch, whatever V8 flag we want to imply in tracing, we define another
integer flag, and the original V8 flag will set it to 0x01 when passing by
commandline, tracing will set it to 0x10 when we start tracing and reset the bit
when we stop tracing.
Review-Url: https://codereview.chromium.org/2436273002
Cr-Commit-Position: refs/heads/master@{#40659}
This patch moves promise specific runtime functions
to runtime-promise.cc from runtime-internal.cc
BUG=v8:5343
Review-Url: https://codereview.chromium.org/2452833003
Cr-Commit-Position: refs/heads/master@{#40618}
Since ZoneLists are essentially non-standard ZoneVectors and have a bad
growing behaviour (ZoneList-allocations make up ~50% of website parse
zone memory) we should stop using them. The zone-containers are merely
a clean-up, with none of them actually better suited to be used with
zones. This new datastructure allows most operations of a LinkedList (
except pop_first and insertAt/removeAt) but uses about the same memory
as a well-initialized ZoneVector/ZoneList (<3% overhead with reasonably
large lists). It also never attempts to free memory again (which would
not work in zones anyway).
The ZoneChunkList is essentially a doubly-linked-list of arrays of
variable size.
Some test-results where I tried storing 16k pointers in different list
types (lists themselves also zone-allocated):
List type Zone memory used Time taken
-----------------------------------------------------------------------
Zone array (for comparison) 131072 B
Ideally initialized ZoneList 131088 B 0.062ms
ChunkZoneList 134744 B 0.052ms <--new thing
ZoneDeque 141744 B
ZoneLinkedList 393264 B
Initially empty ZoneList 524168 B 0.171ms <--right now
ChunkZoneList only push_front 524320 B
Review-Url: https://codereview.chromium.org/2449383002
Cr-Commit-Position: refs/heads/master@{#40602}
The meaning of the HValue::kAllowUndefinedAsNaN is actually ToNumber
conversion (except for the uses in HBranch and HCompareHoleAndBranch,
which were confusing and useless anyways), so fix the naming to match
that.
Also properly integrate the handling of this flag with the existing
truncation analysis that is run as part of the representation changes
phase (i.e. where we already deal with truncating to int32 and smi).
This is done in preparation of allowing Crankshaft to handle any kind
of Oddball in the ToNumber truncation, instead of just undefined for
truncation ToNumber and undefined or boolean for ToInt32. It also helps
to make Crankshaft somewhat more compatible with the (saner)
implementation in TurboFan.
R=yangguo@chromium.org
BUG=v8:5400
Review-Url: https://codereview.chromium.org/2449353002
Cr-Commit-Position: refs/heads/master@{#40577}
This CL removes code that is now unused since the port of regexp.js has been
completed. Removed functions / classes are:
* regexp.js (GetSubstitution moved to string.js)
* RegExpConstructResult stub
* RegExpFlags intrinsic
* RegExpSource intrinsic
* RegExpInitializeAndCompile runtime function
BUG=v8:5339
Review-Url: https://codereview.chromium.org/2448463002
Cr-Commit-Position: refs/heads/master@{#40547}
Depending on the inputs the fuzzer creates multiple functions. These
functions can have signatures with an int32 return value and up to three
parameters of type int32, int64, float32, or float64.
R=titzer@chromium.org, clemensh@chromium.org
Review-Url: https://codereview.chromium.org/2447643002
Cr-Commit-Position: refs/heads/master@{#40530}
Additionally, remove all code related to the old-style slots filtering and black area end markers.
BUG=chromium:648568
Review-Url: https://chromiumcodereview.appspot.com/2440683002
Cr-Commit-Position: refs/heads/master@{#40494}
Reason for revert:
https://build.chromium.org/p/client.v8.ports/builders/V8%20Android%20Arm64%20-%20builder/builds/4851
Original issue's description:
> Update implementation of atomics with latest Chromium version but use compiler builtin atomics
>
> Ideally, we would use the standard library. However, when we are compiling against an older version of the standard library the atomic implementation may be slow.
>
> BUG=
TBR=mlippautz@chromium.org,ulan@chromium.org,jarin@chromium.org,hpayer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=
Review-Url: https://chromiumcodereview.appspot.com/2438983002
Cr-Commit-Position: refs/heads/master@{#40489}
Ideally, we would use the standard library. However, when we are compiling against an older version of the standard library the atomic implementation may be slow.
BUG=
Review-Url: https://chromiumcodereview.appspot.com/2425963002
Cr-Commit-Position: refs/heads/master@{#40488}
Implements the variations of CreateArrayIterator() in TFJ builtins
(ArrayPrototypeValues, ArrayPrototypeEntries and ArrayPrototypeKeys), and
provides two new Object types with numerous maps which identify certain
behaviours, which will be useful for inlining.
Removes src/js/array-iterator.js entirely
Also adds support for printing Symbol literals inserted by the Parser during
desugaring when FLAG_print_builtin_ast is set to true.
BUG=v8:5388
R=bmeurer@chromium.org, cbruni@chromium.orgTBR=ulan@chromium.org
Review-Url: https://codereview.chromium.org/2405253006
Cr-Commit-Position: refs/heads/master@{#40373}
Use sparingly!
This doesn't add any really new functionality, other than making it more
convenient to do this.
This will primarily be used to wrap a WasmModule to be referenced from a
JSObject that represents an instance. There is one WasmModule C++ object
per parsed WasmModule, so this should not be more than a handful or a few
dozen in well-behaved programs.
R=rossberg@chromium.org,mlippautz@chromium.org
BUG=
Review-Url: https://codereview.chromium.org/2409173005
Cr-Commit-Position: refs/heads/master@{#40346}
... to keep all the pieces in one place for easier modifications.
This CL also adds a new runtime call stats bucket: KeyedLoadIC_LoadElementDH.
BUG=
Review-Url: https://codereview.chromium.org/2412983008
Cr-Commit-Position: refs/heads/master@{#40314}
This CL is in preparation for the upcoming port of
RegExp.prototype.replace, which will need use these methods in
runtime-regexp.cc. Moving them in advance makes that diff less noisy.
BUG=v8:5339
Review-Url: https://codereview.chromium.org/2398413002
Cr-Commit-Position: refs/heads/master@{#40229}
Introduce AccessCompilerData which hangs off the Isolate, and initialize
it when the first PropertyAccessCompiler is instantiated. This avoids
TSAN failures when trying to access load/store calling convention arrays.
BUG=v8:5427
Review-Url: https://codereview.chromium.org/2389313002
Cr-Commit-Position: refs/heads/master@{#40055}
Reason for revert:
Speculative revert due to very strange-looking win/dbg failures
which reference SignedDivisionByConstant:
https://build.chromium.org/p/client.v8/builders/V8%20Win64%20-%20debug/builds/12736
Original issue's description:
> Reland "Turn libbase into a component"
>
> Original issue's description:
> > Turn libbase into a component
> >
> > This is a precondition for turning libplatform into a component
> >
> > BUG=v8:5412
> > R=jgruber@chromium.org,machenbach@chromium.org
> > CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_compile_
> dbg_ng;master.tryserver.chromium.android:android_clang_dbg_recipe
> >
> > Committed: https://crrev.com/614e615775f732d71b5ee94ed29737d8de687104
> > Cr-Commit-Position: refs/heads/master@{#39950}
>
> BUG=v8:5412
> TBR=jgruber@chromium.org,machenbach@chromium.org
> CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_compile_dbg_ng;master.tryserver.chromium.android:android_clang_dbg_recipe;master.tryserver.chromium.mac:mac_chromium_compile_dbg_ng
>
> Committed: https://crrev.com/17cb51254cafa932025e9980b60f89f756d411cb
> Cr-Commit-Position: refs/heads/master@{#39969}
TBR=jgruber@chromium.org,machenbach@chromium.org,jochen@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5412
Review-Url: https://codereview.chromium.org/2396933002
Cr-Commit-Position: refs/heads/master@{#40009}
It is currently being rolled behind the --turbo_verify_machine_graph flag.
BUG=
Review-Url: https://codereview.chromium.org/2388313003
Cr-Commit-Position: refs/heads/master@{#39976}
Original issue's description:
> Turn libbase into a component
>
> This is a precondition for turning libplatform into a component
>
> BUG=v8:5412
> R=jgruber@chromium.org,machenbach@chromium.org
> CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_compile_
dbg_ng;master.tryserver.chromium.android:android_clang_dbg_recipe
>
> Committed: https://crrev.com/614e615775f732d71b5ee94ed29737d8de687104
> Cr-Commit-Position: refs/heads/master@{#39950}
BUG=v8:5412
TBR=jgruber@chromium.org,machenbach@chromium.org
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_compile_dbg_ng;master.tryserver.chromium.android:android_clang_dbg_recipe;master.tryserver.chromium.mac:mac_chromium_compile_dbg_ng
Review-Url: https://codereview.chromium.org/2395553002
Cr-Commit-Position: refs/heads/master@{#39969}
Reason for revert:
Main suspect for roll block:
https://codereview.chromium.org/2387403002/
Original issue's description:
> Turn libbase into a component
>
> This is a precondition for turning libplatform into a component
>
> BUG=v8:5412
> R=jgruber@chromium.org,machenbach@chromium.org
> CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_compile_dbg_ng;master.tryserver.chromium.android:android_clang_dbg_recipe
>
> Committed: https://crrev.com/614e615775f732d71b5ee94ed29737d8de687104
> Cr-Commit-Position: refs/heads/master@{#39950}
TBR=jgruber@chromium.org,jochen@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5412
Review-Url: https://codereview.chromium.org/2393603002
Cr-Commit-Position: refs/heads/master@{#39960}
This is a precondition for turning libplatform into a component
BUG=v8:5412
R=jgruber@chromium.org,machenbach@chromium.org
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_compile_dbg_ng;master.tryserver.chromium.android:android_clang_dbg_recipe
Review-Url: https://codereview.chromium.org/2381273002
Cr-Commit-Position: refs/heads/master@{#39950}
There are only a few occasions where we allocate a register in an outer
expression allocation scope, which makes the costly free-list approach
of the BytecodeRegisterAllocator unecessary. This CL replaces all
occurrences with moves to the accumulator and stores to a register
allocated in the correct scope. By doing this, we can simplify the
BytecodeRegisterAllocator to be a simple bump-pointer allocator
with registers released in the same order as allocated.
The following changes are also made:
- Make BytecodeRegisterOptimizer able to use registers which have been
unallocated, but not yet reused
- Remove RegisterExpressionResultScope and rename
AccumulatorExpressionResultScope to ValueExpressionResultScope
- Introduce RegisterList to represent consecutive register
allocations, and use this for operands to call bytecodes.
By avoiding the free-list handling, this gives another couple of
percent on CodeLoad.
BUG=v8:4280
Review-Url: https://codereview.chromium.org/2369873002
Cr-Commit-Position: refs/heads/master@{#39905}
This ports RegExp.prototype.exec to a TurboFan builtin.
LastMatchInfo is now stored on the context in order to be able to access
it from the stub.
Unmodified RegExp instances go through a fast path of accessing the
lastIndex property as an in-object field, while modified instances call
into runtime for lastIndex loads and stores.
Octane/regexp shows slight improvements (between 0 and 5%) with this CL.
BUG=v8:5339
Review-Url: https://codereview.chromium.org/2375953002
Cr-Commit-Position: refs/heads/master@{#39899}
Tracing CPU profiler allows V8 to automatically collect CPU profile when tracing
is started with category v8.cpu_profile2 enabled.
BUG=chromium:406277
Review-Url: https://codereview.chromium.org/2378143003
Cr-Commit-Position: refs/heads/master@{#39855}
V8 is collecting a growing amount of fuzzers, all of which take substantial
space on the bots and in chromium build archives. This CL improves that
situation by allowing component (shared library) builds for almost all fuzzers.
The parser fuzzer is handled as an exception since it would require exporting a
large number of additional functions.
A component build results in about a 50-100x improvement in file size for each
fuzzer (~50M-100M to around 1.1M).
BUG=chromium:648864
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_compile_dbg_ng;master.tryserver.chromium.android:android_clang_dbg_recipe
Review-Url: https://codereview.chromium.org/2360983002
Cr-Commit-Position: refs/heads/master@{#39709}
The file formerly known as src/js/harmony-async-await.js does not
expose anything directly to JavaScript code; it just makes a few
functions available on the native context for the parser desugaring
to expand into. Experimental natives have various issues with
larger amounts of code, so this patch moves the JS builtins to
support async functions out of experimental natives and into the
core snapshot. The change would be done eventually anyway, but this
patch does it before removing the flag to support shipping the
feature while avoiding the pitfalls of experimental natives.
Drive by cleanup: remove more unused functions from the whitelist for experimental natives.
BUG=v8:5427,v8:4483
Review-Url: https://codereview.chromium.org/2365123002
Cr-Commit-Position: refs/heads/master@{#39706}
This CL optimizes the code in BytecodeArrayBuilder and
BytecodeArrayWriter by making the following main changes:
- Move operand scale calculation out of BytecodeArrayWriter to the
BytecodeNode constructor, where the decision on which operands are
scalable can generally be statically decided by the compiler.
- Move the maximum register calculation out of BytecodeArrayWriter
and into BytecodeRegisterOptimizer (which is the only place outside
BytecodeGenerator which updates which registers are used). This
avoids the BytecodeArrayWriter needing to know the operand types
of a node as it writes it.
- Modify EmitBytecodes to use individual push_backs rather than
building a buffer and calling insert, since this turns out to be faster.
- Initialize BytecodeArrayWriter's bytecode vector by reserving 512
bytes,
- Make common functions in Bytecodes constexpr so that they
can be statically calculated by the compiler.
- Move common functions and constructors in Bytecodes and
BytecodeNode to the header so that they can be inlined.
- Change large static switch statements in Bytecodes to const array
lookups, and move to the header to allow inlining.
I also took the opportunity to remove a number of unused helper
functions, and rework some others for consistency.
This reduces the percentage of time spent in making BytecodeArrays
in CodeLoad from ~15% to ~11% according to perf. The
CoadLoad score increase by around 2%.
BUG=v8:4280
Committed: https://crrev.com/b11a8b4d41bf09d6b3d6cf214fe3fb61faf01a64
Review-Url: https://codereview.chromium.org/2351763002
Cr-Original-Commit-Position: refs/heads/master@{#39599}
Cr-Commit-Position: refs/heads/master@{#39637}
Reason for revert:
Prime suspect for roll blocker: https://codereview.chromium.org/2362503002/
Original issue's description:
> [Interpreter] Optimize BytecodeArrayBuilder and BytecodeArrayWriter.
>
> This CL optimizes the code in BytecodeArrayBuilder and
> BytecodeArrayWriter by making the following main changes:
>
> - Move operand scale calculation out of BytecodeArrayWriter to the
> BytecodeNode constructor, where the decision on which operands are
> scalable can generally be statically decided by the compiler.
> - Move the maximum register calculation out of BytecodeArrayWriter
> and into BytecodeRegisterOptimizer (which is the only place outside
> BytecodeGenerator which updates which registers are used). This
> avoids the BytecodeArrayWriter needing to know the operand types
> of a node as it writes it.
> - Modify EmitBytecodes to use individual push_backs rather than
> building a buffer and calling insert, since this turns out to be faster.
> - Initialize BytecodeArrayWriter's bytecode vector by reserving 512
> bytes,
> - Make common functions in Bytecodes constexpr so that they
> can be statically calculated by the compiler.
> - Move common functions and constructors in Bytecodes and
> BytecodeNode to the header so that they can be inlined.
> - Change large static switch statements in Bytecodes to const array
> lookups, and move to the header to allow inlining.
>
> I also took the opportunity to remove a number of unused helper
> functions, and rework some others for consistency.
>
> This reduces the percentage of time spent in making BytecodeArrays
> in CodeLoad from ~15% to ~11% according to perf. The
> CoadLoad score increase by around 2%.
>
> BUG=v8:4280
>
> Committed: https://crrev.com/b11a8b4d41bf09d6b3d6cf214fe3fb61faf01a64
> Cr-Commit-Position: refs/heads/master@{#39599}
TBR=mythria@chromium.org,leszeks@chromium.org,rmcilroy@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4280
Review-Url: https://codereview.chromium.org/2360193003
Cr-Commit-Position: refs/heads/master@{#39612}
This CL optimizes the code in BytecodeArrayBuilder and
BytecodeArrayWriter by making the following main changes:
- Move operand scale calculation out of BytecodeArrayWriter to the
BytecodeNode constructor, where the decision on which operands are
scalable can generally be statically decided by the compiler.
- Move the maximum register calculation out of BytecodeArrayWriter
and into BytecodeRegisterOptimizer (which is the only place outside
BytecodeGenerator which updates which registers are used). This
avoids the BytecodeArrayWriter needing to know the operand types
of a node as it writes it.
- Modify EmitBytecodes to use individual push_backs rather than
building a buffer and calling insert, since this turns out to be faster.
- Initialize BytecodeArrayWriter's bytecode vector by reserving 512
bytes,
- Make common functions in Bytecodes constexpr so that they
can be statically calculated by the compiler.
- Move common functions and constructors in Bytecodes and
BytecodeNode to the header so that they can be inlined.
- Change large static switch statements in Bytecodes to const array
lookups, and move to the header to allow inlining.
I also took the opportunity to remove a number of unused helper
functions, and rework some others for consistency.
This reduces the percentage of time spent in making BytecodeArrays
in CodeLoad from ~15% to ~11% according to perf. The
CoadLoad score increase by around 2%.
BUG=v8:4280
Review-Url: https://codereview.chromium.org/2351763002
Cr-Commit-Position: refs/heads/master@{#39599}
This also adds sources missing for PPC and x87, fixes a few
missing files in gyp due to wrong quotation and a few that
were simply not included.
The gn files are now authoritative, but the gcmole gyp and
gn source lists are enforced to match exactly.
This additional enforcement helped finding the bugs above
and will be removed when we deprecate the gyp files.
BUG=614645
NOTRY=true
Review-Url: https://codereview.chromium.org/2352103002
Cr-Commit-Position: refs/heads/master@{#39592}
This is some initial cleanup to keep /src clean. The
AccountingAllocator is actually exclusively used by zones and this
common subfolder makes that more clear.
BUG=v8:5409
Review-Url: https://codereview.chromium.org/2344143003
Cr-Commit-Position: refs/heads/master@{#39558}
Full code uses patching ICs for this feedback, and the interpreter uses
the type feedback vector. It's a good idea to code the vector slots
appropriately as ICs so that the runtime profiler can better gauge if
the function is ready for tiering up from Ignition to TurboFan.
As is, the feedback is stored in "general" slots which can't be
characterized by the runtime profiler into feedback states.
This CL addresses that problem. Note that it's also important to
carefully exclude these slots from the profiler's consideration when
determining if you want to optimize from Full code.
BUG=
Review-Url: https://codereview.chromium.org/2342853002
Cr-Commit-Position: refs/heads/master@{#39555}
Adds template parameters for the TemplateHashMapImpl for the key and
value type, to allow them to be something other than pointers. To keep
the impact of this patch low, uses of TemplateHashMapImpl set these
types to void* to emulate the previous behaviour.
This is part of a wider set of changes discussed in:
https://groups.google.com/forum/#!topic/v8-dev/QLsC0XPYLeM
Review-Url: https://codereview.chromium.org/2343123002
Cr-Commit-Position: refs/heads/master@{#39530}
Reason for revert:
Unblocking roll
Original issue's description:
> [d8] Fix the shared-library build
>
> This commit ensures that the d8 shared library build uses the same logic as
> the standard static build by exporting relevant functions and classes.
>
> BUG=chromium:646337
>
> Committed: https://crrev.com/2c10ca8086a4d595ecf9aa843d2031b068470d65
> Cr-Commit-Position: refs/heads/master@{#39503}
TBR=jochen@chromium.org,vogelheim@chromium.org,bmeurer@chromium.org,titzer@chromium.org,jgruber@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:646337
Review-Url: https://codereview.chromium.org/2356703003
Cr-Commit-Position: refs/heads/master@{#39526}
This commit ensures that the d8 shared library build uses the same logic as
the standard static build by exporting relevant functions and classes.
BUG=chromium:646337
Review-Url: https://codereview.chromium.org/2342563002
Cr-Commit-Position: refs/heads/master@{#39503}
This flag has been flipped off since 52, so it is due for removal.
R=adamk@chromium.org,caitp@igalia.com
BUG=v8:3785
CQ_INCLUDE_TRYBOTS=master.tryserver.v8:v8_linux_noi18n_rel_ng
Review-Url: https://codereview.chromium.org/2268633002
Cr-Commit-Position: refs/heads/master@{#39435}
This CL adds fuzzers for the wasm module sections 'types', 'names',
'globals', 'imports', 'function signatures', 'memory', and 'data', one
fuzzer per section. No fuzzers are added for the other sections because
either there already exists a fuzzer (e.g. wasm-code), or there exist
inter-section dependencies.
To avoid introducing a bunch executables which would make compilation
with make slow, I introduce a single executable
'v8_simple_wasm_section_fuzzer' which calls the fuzzers mentioned above.
This executable is run by the trybots and ensures that the fuzzers
actually compile. For debugging I introduce commandline parameters which
allow to execute the specific fuzzers from 'v8_simple_wasm_section_fuzzer'.
R=titzer@chromium.org, jochen@chromium.org, mstarzinger@chromium.org
Review-Url: https://codereview.chromium.org/2336603002
Cr-Commit-Position: refs/heads/master@{#39413}
The wasm-module-runner is used both in cctests and in fuzzers. As
discussed offline, it is weird to include cctest header files in
fuzzers, so I introduce a new test/common directory which contains the
common files.
R=titzer@chromium.org, jochen@chromium.org
Review-Url: https://codereview.chromium.org/2335193002
Cr-Commit-Position: refs/heads/master@{#39411}
With this CL the wasm-code-fuzzer first decodes and interprets the test
case generated by the fuzzer. It then compiles the test case, but only
executes the compiled instance if the interpretation of the test case
was successful. If the compiled instance is executed, then the result of
the execution is compared with the result of the interpretation.
Additionally this CL refactors the CompileAndRunWasmModule function in
wasm-module.cc to resuse code in the call to the interpreter.
R=titzer@chromium.org
Review-Url: https://codereview.chromium.org/2321443002
Cr-Commit-Position: refs/heads/master@{#39351}
- inspector becomes a dependency of v8_base;
- generated public protocol files are placed to gen/v8/include/inspector/<Domain.h>;
- added v8_enable_inspector_override to be used in embedders (gn only);
- combined public headers into v8-inspector.h and v8-inspector-protocol.h.
BUG=chromium:635948
Review-Url: https://codereview.chromium.org/2292053003
Cr-Commit-Position: refs/heads/master@{#39226}
Spec discussion: https://github.com/tc39/ecma402/issues/30
It's in stage 4 and Firefox has already implemented it.
For now, it's added to HARMONY_IN_PROGRESS bucket behind
'--datetime-format-to-parts' flag.
BUG=v8:5244
TEST=intl/date-format/date-format-to-parts.js
TEST=test262/intl402/DateTimeFormat/prototype/formatToParts/*
Review-Url: https://codereview.chromium.org/2273953003
Cr-Commit-Position: refs/heads/master@{#39225}
Reason for revert:
Performance regressions: crbug.com/644087
Clusterfuzz: crbug.com/644074
We'll reland all regexp changes at once when the port is complete and at least performance-neutral, since the partial port requires slow workarounds.
Original issue's description:
> [regexp] Port RegExpConstructor
>
> BUG=v8:5339
>
> Committed: https://crrev.com/0aa80be16b8d876999066545c2922e1291e09610
> Cr-Commit-Position: refs/heads/master@{#39074}
TBR=bmeurer@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=v8:5339
Review-Url: https://codereview.chromium.org/2312743002
Cr-Commit-Position: refs/heads/master@{#39177}
This makes for slightly faster rebuilds when touching parser-base.h
(which changes frequently!). Also takes care of an old TODO,
moving CompileTimeValue into its own file under ast/, where it
properly belongs.
BUG=v8:5294
Review-Url: https://codereview.chromium.org/2305883002
Cr-Commit-Position: refs/heads/master@{#39141}
Our Type class has a semantic and representational dimension.
Much code in src/ast, Crankshaft and Turbofan is based on it.
Going forward in Turbofan we'd like to remove representational information
entirely. To that end, new type AstType has been created to preserve
existing behavior for the benefit of Crankshaft and the AST.
BUG=
Review-Url: https://codereview.chromium.org/2302283002
Cr-Commit-Position: refs/heads/master@{#39135}
Correct a small bug which throws a compile-time assertion for ARMv8
builds since this change:
https://codereview.chromium.org/2223433002
This does not add full support for ARMv8 instructions; it simply sets
the CAN_USE_ARMV7_INSTRUCTIONS define on ARMv8 builds.
BUG=
Review-Url: https://codereview.chromium.org/2293253004
Cr-Commit-Position: refs/heads/master@{#39087}
This way, many files which only need CompilationInfo but not compiler.h
and its dependencies can include just compilation-info.h.
BUG=
Review-Url: https://codereview.chromium.org/2284313003
Cr-Commit-Position: refs/heads/master@{#39038}
For asm.js we now have a dedicated AsmTyper, that uses it's own type
system (which is tailored towards asm.js), and so we don't need the
special asm.js types anymore in the TypeCache. This also moves the
TypeCache into the src/compiler directory, because it doesn't make
sense to use outside anyways.
TBR=ahaas@chromium.orgR=jarin@chromium.org
BUG=v8:5267
Review-Url: https://codereview.chromium.org/2289573002
Cr-Commit-Position: refs/heads/master@{#38964}
Reason for revert:
Significantly tanks parsing. We probably should just keep on doing what we're doing: partially deserialize while resolving variables. If we do scope-info backed resolution after regular resolution based on remaining free variables, we can probably reduce the time-frame of that part. We soon after anyway need to sync with the main thread.
Original issue's description:
> Always deserialize scope infos for parsing
>
> When looking up variables in the ScopeInfo, we did a linear scan of the
> ScopeInfo. Since that's unacceptably slow, a context slot cache was added
> that would speed up repeated lookups of the same variable.
>
> Instead, just always fully convert the ScopeInfo into scopes, so they can
> lookup variables without scanning the ScopeInfo.
>
> This also allows for removing the now unused ContextSlotCache.
>
> R=adamk@chromium.org,verwaest@chromium.org,marja@chromium.org
> BUG=v8:5315
>
> Committed: https://crrev.com/81f824cad18e4dc873a8838943217eb9c9f0c1f0
> Cr-Commit-Position: refs/heads/master@{#38953}
TBR=adamk@chromium.org,marja@chromium.org,jochen@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5315
Review-Url: https://codereview.chromium.org/2287783003
Cr-Commit-Position: refs/heads/master@{#38958}
When looking up variables in the ScopeInfo, we did a linear scan of the
ScopeInfo. Since that's unacceptably slow, a context slot cache was added
that would speed up repeated lookups of the same variable.
Instead, just always fully convert the ScopeInfo into scopes, so they can
lookup variables without scanning the ScopeInfo.
This also allows for removing the now unused ContextSlotCache.
R=adamk@chromium.org,verwaest@chromium.org,marja@chromium.org
BUG=v8:5315
Review-Url: https://codereview.chromium.org/2280933002
Cr-Commit-Position: refs/heads/master@{#38953}
Introduce a new TypedOptimization reducer that contains the type
based optimization reduction steps, which are not (directly)
related to lowering JavaScript operators based on types (which is
what JSTypedLowering is supposed to do).
This also addresses a chicken-and-egg problem that we see in the
Octane/Mandreel benchmark where type based constant folding isn't
applied to the numeric comparison operators introduced by the
JSTypedLowering itself, and thus gives up to 10% speedup for the
benchmark.
BUG=v8:5267
Review-Url: https://codereview.chromium.org/2280673003
Cr-Commit-Position: refs/heads/master@{#38928}
DuplicateFinder isn't actually used by the Scanner, except for one
convenience function which we should probably remove, also.
BUG=
Review-Url: https://codereview.chromium.org/2281443002
Cr-Commit-Position: refs/heads/master@{#38904}
This flag was shipped on in 52, so it's due for removal. The patch includes
removing the deprecated and unused-in-Blink API Promise::Chain, and many
test updates.
R=adamk@chromium.org
BUG=v8:4633
Review-Url: https://codereview.chromium.org/2267033002
Cr-Commit-Position: refs/heads/master@{#38804}
When doing a component build, some test binaries link against the object
files directly, bypassing the components. This results, however, and
rightly so, in linker warnings. In gyp, we just suppressed them. During
the transition to gn, this was dropped for two binaries.
Here I add the suppressions back in.
Long term, we should either change the tests to go through the public
API, or export the required symbols.
BUG=chromium:633688
R=jkummerow@chromium.org
Review-Url: https://codereview.chromium.org/2261123003
Cr-Commit-Position: refs/heads/master@{#38793}
This makes us able to get rid of dependencies to parser.h from places
which only need the ParseInfo, and also gets rid of the curious Parser
<-> Compiler circular dependency.
Also IWYUd where necessary.
BUG=
Review-Url: https://codereview.chromium.org/2268513002
Cr-Commit-Position: refs/heads/master@{#38777}
Adds support for dumping the stack on Windows. Also enables in-process
stack dumping in d8 to dump the stack on exceptions and signals.
This CL changes the format of stack dumps from:
1: V8_Fatal
2: 0x1ac6ba5
3: v8::internal::interpreter::BytecodeGenerator::Visit(v8::internal::AstNode*)
4: v8::internal::interpreter::BytecodeGenerator::VisitForAccumulatorValue(v8::internal::Expression*)
...
To:
./out/x64.debug/d8(v8::base::debug::StackTrace::StackTrace()+0x1e) [0x1c6ee5e]
./out/x64.debug/d8() [0x1c6ede5]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x10330) [0x7fa01193e330]
./out/x64.debug/d8(v8::base::OS::Abort()+0x12) [0x1c6cea2]
./out/x64.debug/d8() [0x1c67538]
./out/x64.debug/d8() [0x1ac80b5]
./out/x64.debug/d8(v8::internal::interpreter::BytecodeGenerator
::Visit(v8::internal::AstNode*)+0x3cb) [0x1ac323b]
./out/x64.debug/d8(v8::internal::interpreter::BytecodeGenerator
::VisitForAccumulatorValue(v8::internal::Expression*)+0x40) [0x1ac2570]
Review-Url: https://codereview.chromium.org/2248393002
Cr-Commit-Position: refs/heads/master@{#38717}
Adds TestResultScope and uses it to directly jump/fall through to the
correct branch in expressions used as branch conditions.
Should enable nicer TurboFan-graphs for easier control-flow
transformations in the future.
BUG=v8:4280
LOG=n
Review-Url: https://codereview.chromium.org/2242463002
Cr-Commit-Position: refs/heads/master@{#38634}
This adds a gyp/gn variable to control printing to stdout
on Android. This is false by default and true for all
v8 stand-alone android bots.
BUG=chromium:629806
Review-Url: https://codereview.chromium.org/2183063002
Cr-Commit-Position: refs/heads/master@{#38253}
Reason for revert:
Breaks roll: https://codereview.chromium.org/2182043004/
Original issue's description:
> [gn] Don't use PIE for host executables
>
> Using PIE switches on ASLR. With mksnapshot, this can lead
> to non-deterministic snapshots.
>
> BUG=v8:5233
>
> Committed: https://crrev.com/4ca39b53245619d94a80a93939613774e68e4649
> Cr-Commit-Position: refs/heads/master@{#38084}
TBR=jochen@chromium.org,vogelheim@chromium.org,yangguo@chromium.org,machenbach@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5233
Review-Url: https://codereview.chromium.org/2187613003
Cr-Commit-Position: refs/heads/master@{#38092}
Using PIE switches on ASLR. With mksnapshot, this can lead
to non-deterministic snapshots.
BUG=v8:5233
Review-Url: https://codereview.chromium.org/2179303003
Cr-Commit-Position: refs/heads/master@{#38084}
The new phase will detect loop variable, infer bounds and bake them into
the type.
Review-Url: https://codereview.chromium.org/2164263003
Cr-Commit-Position: refs/heads/master@{#38077}
Reason for revert:
Revert this CL due to V8 Arm Builder failure and V8 Mips Builder failure.
https://build.chromium.org/p/client.v8.ports/builders/V8%20Arm%20-%20builder/builds/2456https://build.chromium.org/p/client.v8.ports/builders/V8%20Mips%20-%20builder/builds/2506
Original issue's description:
> [Tracing] V8 Tracing Controller
>
> V8 has had a trace event macro interface for while, but without a tracing
> controller a standalone V8 would be unable to collect traces.
>
> This CL introduces a complete Tracing Controller system for V8.
> It is fully function except that it does not yet store trace event args.
>
> This CL has a few components,
> The tracing controller itself, contributed by the author of this CL
> The Trace config (including the parser), contributed by lpy@
> The Trace Object, Trace Writer, and Trace Buffer are all contributed by rksang@
>
> BUG=v8:4561
> LOG=N
>
> Committed: https://crrev.com/3d598452679ce208ad9b2f48e0fb3fae352ce375
> Cr-Commit-Position: refs/heads/master@{#38073}
TBR=jochen@chromium.org,mattloring@google.com,rskang@google.com,yangguo@chromium.org,fmeawad@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4561
Review-Url: https://codereview.chromium.org/2183943002
Cr-Commit-Position: refs/heads/master@{#38074}
V8 has had a trace event macro interface for while, but without a tracing
controller a standalone V8 would be unable to collect traces.
This CL introduces a complete Tracing Controller system for V8.
It is fully function except that it does not yet store trace event args.
This CL has a few components,
The tracing controller itself, contributed by the author of this CL
The Trace config (including the parser), contributed by lpy@
The Trace Object, Trace Writer, and Trace Buffer are all contributed by rksang@
BUG=v8:4561
LOG=N
Review-Url: https://codereview.chromium.org/2137013006
Cr-Commit-Position: refs/heads/master@{#38073}
