The advantage of an explicit Abort that the interpreter and the compiler know
that aborting cannot continue or throw or deopt. As a result we generate less
code and we do not confuse the compiler if the environment is not set up for
throwing (as in the generator dispatch that fails validation in
crbug.com/762057).

Bug: chromium:762057
Change-Id: I3e88f78be32f31ac49b1845595255f802c405ed7
Reviewed-on: https://chromium-review.googlesource.com/657025
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47922}

JS runtime calls are always created with undefined recievers, so make the
bytecode behave similarly to CallUndefinedReciever such that we don't need
to push an explicit undefined register for the receiver for such calls.

Modifies the Async[Generator/Function]Await[Caught/Uncaught] runtime calls
to pass the generator in the first argument rather than the reciever since
these runtime calls were desugered in the bytecode generator and explicitly
passed the generator in the receiver.

Change-Id: I36c8087bb3b663dccd805bfdb1eea04eb6a73269
Reviewed-on: https://chromium-review.googlesource.com/654257Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47870}

Only the error cases of overwriting readonly properties need the
language_mode to decide whether to throw or be silent. Reading it
from the feedback vector's metadata (just like the C++ code in
ic.cc does) removes the need to duplicate each stub for each
language_mode ("StoreIC" + "StoreICStrict" etc.).

Change-Id: Ic0c67f9d40ca36c65e41b4f162b2ab70d155e549
Reviewed-on: https://chromium-review.googlesource.com/647373Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47836}

Bug: 
Change-Id: Iedd273d517e2ee2e548a5e9732689114800e6128
Reviewed-on: https://chromium-review.googlesource.com/649749Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47822}

In the BytecodeGraphBuilder we insert a SOFT deopt whenever we see an
IC whose state is UNINITIALIZED, i.e. a LOAD_IC or a STORE_IC. This
greatly reduces the size of the generated graphs (and also helps to
improve generated code quality). However for COMPARE_IC and BINARY_OP_IC
we used to stick in the generic JavaScript node instead, which does
generate code and might block optimizations because its sitting in
the effect chain. This is changed now to always SOFT deopt for
UNINITIALIZED instead, consistently with the other ICs.

Bug: v8:6760
Change-Id: I2ac7469fa86512a2fd909fdde2c6425977694811
Reviewed-on: https://chromium-review.googlesource.com/645858
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47771}

This CL adds support to optimize for..in in fast enum-cache mode to the
same degree that it was optimized in Crankshaft, without adding the same
deoptimization loop that Crankshaft had with missing enum cache indices.
That means code like

  for (var k in o) {
    var v = o[k];
    // ...
  }

and code like

  for (var k in o) {
    if (Object.prototype.hasOwnProperty.call(o, k)) {
      var v = o[k];
      // ...
    }
  }

which follows the https://eslint.org/docs/rules/guard-for-in linter
rule, can now utilize the enum cache indices if o has only fast
properties on the receiver, which speeds up the access o[k]
significantly and reduces the pollution of the global megamorphic
stub cache.

For example the micro-benchmark in the tracking bug v8:6702 now runs
faster than ever before:

 forIn: 1516 ms.
 forInHasOwnProperty: 1674 ms.
 forInHasOwnPropertySafe: 1595 ms.
 forInSum: 2051 ms.
 forInSumSafe: 2215 ms.

Compared to numbers from V8 5.8 which is the last version running with
Crankshaft

 forIn: 1641 ms.
 forInHasOwnProperty: 1719 ms.
 forInHasOwnPropertySafe: 1802 ms.
 forInSum: 2226 ms.
 forInSumSafe: 2409 ms.

and V8 6.0 which is the current stable version with TurboFan:

 forIn: 1713 ms.
 forInHasOwnProperty: 5417 ms.
 forInHasOwnPropertySafe: 5324 ms.
 forInSum: 7556 ms.
 forInSumSafe: 11067 ms.

It also improves the throughput on the string-fasta benchmark by
around 7-10%, and there seems to be a ~5% improvement on the
Speedometer/React benchmark locally.

For this to work, the ForInPrepare bytecode was split into
ForInEnumerate and ForInPrepare, which is very similar to how it was
handled in Fullcodegen initially. In TurboFan we introduce a new
operator LoadFieldByIndex that does the dynamic property load.

This also removes the CheckMapValue operator again in favor of
just using LoadField, ReferenceEqual and CheckIf, which work
automatically with the EscapeAnalysis and the
BranchConditionElimination.

Bug: v8:6702
Change-Id: I91235413eea478ba77ace7bd14bb2f62e155dd9a
Reviewed-on: https://chromium-review.googlesource.com/645949
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47768}

Bug: v8:5267
Change-Id: Iea44ba7ee6ba09580176936e6157d63c53d06446
Reviewed-on: https://chromium-review.googlesource.com/646021
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47762}

Bug: v8:6211
Change-Id: I0f15c59b7b786ab327e4ab548523095dd85ba83e
Reviewed-on: https://chromium-review.googlesource.com/637835Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47650}

This is just a refactoring in preparation for typing the speculative
integer operation as safe integers.

Bug: v8:5267
Change-Id: I56da91a72655a0733b2cf04afcf33cb1d2aa1415
Reviewed-on: https://chromium-review.googlesource.com/637830Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47640}

Optimize the common pattern

  for (var i in o) {
    if (Object.prototype.hasOwnProperty.call(o, i)) {
      // do something
    }
  }

which is part of the guard-for-in style in ESLint (see the documentation
at https://eslint.org/docs/rules/guard-for-in for details). This pattern
also shows up in React and Ember applications quite a lot (and is tested
by the appropriate Speedometer benchmarks, although not dominating those
benchmarks, since they spent a lot of time in non-TurboFan'ed code).

This improves the forInHasOwnProperty and forInHasOwnPropertySafe micro-
benchmarks in v8:6702, which look like this

  function forInHasOwnProperty(o) {
    var result = 0;
    for (var i in o) {
      if (o.hasOwnProperty(i)) {
        result += 1;
      }
    }
    return result;
  }

  function forInHasOwnPropertySafe(o) {
    var result = 0;
    for (var i in o) {
      if (Object.prototype.hasOwnProperty.call(o, i)) {
        result += 1;
      }
    }
    return result;
  }

by around 4x and allows for additional optimizations in the future, by
also elimiating the megamorphic load when accessing the enumerated
properties.

This changes the interpreter ForInNext bytecode to collect more precise
feedback about the for-in state, which now consists of three individual
states: UNINITIALIZED, MEGAMORPHIC and GENERIC. The MEGAMORPHIC state
means that the ForInNext has only seen objects with a usable enum cache
thus far, whereas GENERIC means that we have seen some slow-mode for..in
objects as well.

R=jarin@chromium.org

Bug: v8:6702
Change-Id: Ibcd75ea9b58c3b4f9219f11bc37eb04a2b985604
Reviewed-on: https://chromium-review.googlesource.com/636964
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47632}

Since the AST graph builder is gone, no variable should be named osr_ast_id.
This CL replaces it with osr_offset. It designates the offset of the bytecode
where the OSRing was triggered.

Bug: 
Change-Id: Ia53a83b09f917fcd0174da685a18edd3ee3aa01f
Reviewed-on: https://chromium-review.googlesource.com/621008Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47566}

The quite common empty object literal doesn't need an AllocationSite
since it starts off with the general ElementsKind. By using a separate 
bytecode we can directly instantiate the empty object without jumping
to the runtime first.

Note: this experimentally disables pretenuring for empty object
      literals. Depending on the outcome of our benchmarks pretenuring
      will be enabled again or fully removed for empty object literals.

Bug: v8:6211
Change-Id: I2fee81cbefc70865fc436dbd3bc5fc8de04db91c
Reviewed-on: https://chromium-review.googlesource.com/577555
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47467}

The TODO was about wrapping together the sourceposition iterator and the bytecode
iterator. Since the first one is useful in fewer parts than the second, and the
bytecode iterator is more flexible to advance than the sourceposition iterator,
and we would not gain that much more readability, this TODO is removed.

TBR=mstarzinger@chromium.org

Bug: 
Change-Id: I104d0f5f0cd01686ea48d209419bd6bb2ed19bcf
Reviewed-on: https://chromium-review.googlesource.com/621106
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47432}

In graph building, use liveness information to only create Phis
for live registers when merging two environments, or when preparing
a loop header. Similarly, only create loop exit value nodes for
live registers when exiting a loop.

Bug: v8:6701
Change-Id: Id6ac6a5518e6f1762530d871e92a46f42397928b
Reviewed-on: https://chromium-review.googlesource.com/615173
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47389}

The accumulator should never be alive when jumping back to a loop
header, or jumping out of a loop. This means that as far as far as
TurboFan is concerned, we never need to create Phis or LoopExitValues
for the accumulator, as its value should not escape the loop.

For safety, this also augments the IsLivenessValid DCHECK in the
liveness analysis to check that the accumulator is not live in these
cases, and amends the bytecode analysis tests to kill the accumulator
where necessary to ensure this.

As a drive-by, added some comments to the more complex bytecode analysis
tests, since figuring out what they were for and how to fix them took a
non-trivial amount of time.

Change-Id: Idecf76a36681d724134c59768650c23cc6b0e9ef
Reviewed-on: https://chromium-review.googlesource.com/615168
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47388}

Removes the new.target slot from the interpreter's fixed frame. Instead
adds a field to BytecodeArray to get the bytecode's incoming
new.target or generator object register. The InterpreterEntryTrampoline
then sets this register with the incoming new.target (or generator object)
when the function is called. This register can be directly the new.target
or generator object variable if they are LOCAL location, otherwise it is a
temporary register which is then moved to the variable's location during the
function prologue.

This fixes a hack in the deoptimizer where we would set the new.target fixed
slot to undefined in order to avoid extending it's lifetime through the
optimized code - now it's just a standard register and can be optimized away
as normal.

Bug=v8:6644

Change-Id: Ieb8cc34cccefd9fb6634a90cbc77c6002a54f2ae
Reviewed-on: https://chromium-review.googlesource.com/608966
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47320}

Instead of having feedback vector as a subtype of FixedArray with
reserved slots, make it a first-class variable-sized object with a
fixed-size header. This allows us to compress counters to ints in the
header, rather than forcing them to be Smis.

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: Icc5f088ffbc2e2651b845bc71ea42060639e3e48
Reviewed-on: https://chromium-review.googlesource.com/585129
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46935}

Reland of https://chromium-review.googlesource.com/c/543042/.

Now the OSR phase is only used when OSRing from the ast graph builder.
When OSRing from Turbofan, the implementation is now in the graph
building phase, at the beginning of the VisitBytecode function.
We are no longer generating any OSRLoopEntry or OSRNormalEntry nodes,
nor nodes for the possible code of the OSRed function which is before
the OSRed loops.

The trimming and reducing of the OSR phase is not done either. This
change in the way the way the OSR is done enabled to remove the
workaround to the bug mentioned below.

Bug: v8:6112
Bug: v8:6518
Change-Id: Ia02f2138f54fc79cab2f02fed68d9bb522d6ce14
Reviewed-on: https://chromium-review.googlesource.com/584756
Commit-Queue: Alexandre Talon <alexandret@google.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46899}

Remove need for shuffling of accumulator and operand registers when
suspending a generator

BUG=v8:6351
TBR=bmeurer@chromium.org

Change-Id: I372509adc03b9781716412b809639554fe16e372
Reviewed-on: https://chromium-review.googlesource.com/578377
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46883}

Empty Array literals are amongst the most commonly used literal types on our
top25 page list. Using a custom bytecode we can drop the boilerplate for empty
Array literals alltogether. However, we still need a proper AllocationSite to
track ElementsKind transitions.

Bug: v8:6211, chromium:746935
Change-Id: I891eaa778e4e81e138e483a65f04ae00ae30bd28
Reviewed-on: https://chromium-review.googlesource.com/580932Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46875}

Properly hook up the (existing) IC slots for the CallWithSpread and
ConstructWithSpread bytecodes, and change the interpreter to collect
feedback (call counts and regular target function feedback) for those.
There's no integration with the Array constructor yet, since that
requires some yak shaving to thread through the AllocationSite to the
Array constructor stub. Once we have a solution for that, we can also
remove the current code duplication in the Call/Construct IC logic.

Also properly hook up the newly available feedback in TurboFan. This
will fix not only the missing target feedback, but more importantly
the tear-up decisions for optimization are correct now in the presence
of spread calls, and even more importantly the inlining heurstic has
proper call frequencies for those.

Some follow-up changes will be necessary to make sure we use the
feedback even for corner cases that aren't handled properly yet. Also
we should consider collecting feedback about the map of the spread
at some point to be able to always inline the spread calls.

Bug: v8:6399, v8:6527, v8:6630
Change-Id: I818dbcb411fd3951d8e9d31f5d7e794f8d60fa00
Reviewed-on: https://chromium-review.googlesource.com/582647Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46832}

This reverts commit 69c8f16d.

Reason for revert: Causing crashes on Clusterfuzz - http://crbug.com/747154

BUG=chromium:747154

Original change's description:
> [Turbofan] Merged the OSR phase into the graph building phase.
> 
> Now the OSR phase is only used when OSRing from the ast graph builder.
> When OSRing from Turbofan, the implementation is now in the graph
> building phase, at the beginning of the VisitBytecode function.
> We are no longer generating any OSRLoopEntry or OSRNormalEntry nodes,
> nor nodes for the possible code of the OSRed function which is before
> the OSRed loops.
> 
> The trimming and reducing of the OSR phase is not done either. This
> change in the way the way the OSR is done enabled to remove the
> workaround to the bug mentioned below.
> 
> Bug: v8:6112
> Bug: v8:6518
> Change-Id: I1c9231810b923486d55ea618d550d981d695d797
> Reviewed-on: https://chromium-review.googlesource.com/543042
> Commit-Queue: Alexandre Talon <alexandret@google.com>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#46801}

TBR=rmcilroy@chromium.org,mstarzinger@chromium.org,leszeks@chromium.org,alexandret@google.com

Change-Id: Ifa9bf5d86e888a47cad7fb10446b36fda5029604
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:6112, v8:6518
Reviewed-on: https://chromium-review.googlesource.com/581288Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46817}

This reverts commit 4851745f.

Reason for revert: Top crasher on Canary, see https://crbug.com/746935

Original change's description:
> [literals] Introduce CreateEmptyArrayLiteral Bytecode
> 
> Empty Array literals are amongst the most commonly used literal types on our
> top25 page list. Using a custom bytecode we can drop the boilerplate for empty
> Array literals alltogether. However, we still need a proper AllocationSite to
> track ElementsKind transitions.
> 
> Bug: v8:6211
> Change-Id: Id5dbdac0ea8e24dd474e679c902c6e4a2957af1d
> Reviewed-on: https://chromium-review.googlesource.com/567079
> Commit-Queue: Camillo Bruni <cbruni@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#46752}

TBR=rmcilroy@chromium.org,mstarzinger@chromium.org,cbruni@chromium.org,ishell@chromium.org,rmcilroy@google.com
Bug: v8:6211, chromium:746935

Change-Id: Ibf19a923688c071d03bad8661a10e08f8414db56
Reviewed-on: https://chromium-review.googlesource.com/580193
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46804}

Now the OSR phase is only used when OSRing from the ast graph builder.
When OSRing from Turbofan, the implementation is now in the graph
building phase, at the beginning of the VisitBytecode function.
We are no longer generating any OSRLoopEntry or OSRNormalEntry nodes,
nor nodes for the possible code of the OSRed function which is before
the OSRed loops.

The trimming and reducing of the OSR phase is not done either. This
change in the way the way the OSR is done enabled to remove the
workaround to the bug mentioned below.

Bug: v8:6112
Bug: v8:6518
Change-Id: I1c9231810b923486d55ea618d550d981d695d797
Reviewed-on: https://chromium-review.googlesource.com/543042
Commit-Queue: Alexandre Talon <alexandret@google.com>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46801}

There remained a few of regressions and we didn't see any significant
improvement in the real world with this turned on. This CL reverts all the
StringConcat bytecode work which landed.

BUG=v8:6243

Change-Id: I832eb72e880ad41411dbec8fe29f71ef0f2025c8
Reviewed-on: https://chromium-review.googlesource.com/575130
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46769}

Empty Array literals are amongst the most commonly used literal types on our
top25 page list. Using a custom bytecode we can drop the boilerplate for empty
Array literals alltogether. However, we still need a proper AllocationSite to
track ElementsKind transitions.

Bug: v8:6211
Change-Id: Id5dbdac0ea8e24dd474e679c902c6e4a2957af1d
Reviewed-on: https://chromium-review.googlesource.com/567079
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46752}

Nop bytecodes are required only for break locations in debugger. Since nop bytecode doesn't change program state we can remove all of them.

There are at least two changes which this CL produce:
- we don't provide break position when we load local variable (still provide when load variable from global),
- we don't provide break position for statements without actual break positions (e.g. "a;") - these expressions should be super rare and user always can set breakpoint before or after this statement.

More details in one pager: https://docs.google.com/a/google.com/document/d/1JXlQpfMa9vRojbE272b6GMBbrfh6m_00135iAUOJEz8/edit?usp=sharing

Bug: v8:6425
Change-Id: I4aee73d497a84f7b5d89caa6dda6d3060567dfda
Reviewed-on: https://chromium-review.googlesource.com/543161Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46742}

SuspendFlags was originally used by the suspend operation to determine
which field to record the bytecode offset of a suspended generator, and
the value the generator was resumed with. For async generators, await
operations would use a separate field, in order to preserve the previous
yield input value. This was important to ensure `function.sent`
continued to function correctly.

As function.sent is being retired, this allows the removal of support
for that. Given that this was the only real need for SuspendFlags in the
first place (with other uses tacked on as a hack), this involves several
other changes as well:

- Modification of MacroAssembler AssertGeneratorObject. No longer
  accepts a SuspendFlags parameter to determine which type of check to
  perform.
- Removal of `flags` operand from SuspendGenerator bytecode, and the
  GeneratorStore js-operator.
- Removal of `flags` parameter from ResumeGeneratorTrampoline builtins.
- Removal of Runtime functions, interpreter intrinsics and
  AccessBuilders associated with the [[await_input_or_debug_pos]] field
  in JSAsyncGeneratorObject, as this field no longer exists.
- Addition of a new `Yield` AST node (subclass of Suspend) in order to
  prevent the need for the other SuspendFlag values.

BUG=v8:5855
TBR=bmeurer@chromium.org

Change-Id: Iff2881e4742497fe5b774915e988c3d9d8fbe487
Reviewed-on: https://chromium-review.googlesource.com/570485
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46683}

The tail call implementation is hidden behind the --harmony-tailcalls
flag, which is off-by-default (and has been unstaged since February).
It is known to be broken in a variety of cases, including clusterfuzz
security issues (see sample Chromium issues below). To avoid letting
the implementation bitrot further on trunk, this patch removes it.

Bug: v8:4698, chromium:636914, chromium:724746
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng;master.tryserver.v8:v8_linux_noi18n_rel_ng
Change-Id: I9cb547101456a582374fdf7b1a3f044a9ef33e5c
Reviewed-on: https://chromium-review.googlesource.com/569069
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46651}

Similar to JSCall, we can also replace uninitialized JSConstruct nodes
with SOFT deopts to ensure that we don't generate unnecessary dead code.
This for example shows up in the hot parts of the Node event emitter
currently where the generic code for handling events with 4 or more
parameters might not have been run, but we still generate most of the
code because the new Array call in the beginning is not turned into
a SOFT deopt immediately.

Drive-by-fix: Also refactor the BytecodeGraphBuilder's handling of
Construct bytecodes a bit to reduce the amount of code duplication.

BUG=v8:4551, v8:5267
R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2958253002
Cr-Commit-Position: refs/heads/master@{#46339}

This avoids usage of the costly {NodeProperties::IsExceptionalCall}
predicate during graph building. The result of this predicate is no
longer needed.

R=leszeks@chromium.org

Change-Id: Ief0c37b598ca51ea5d604f47d964bcbfb89a5206
Reviewed-on: https://chromium-review.googlesource.com/555517Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46327}

Adds a CheckString to all operand inputs of JSStringConcat. The operands are
already known to be strings, so this will get eliminated in almost all cases,
however, if there is a yield within the concatenation then we lose the
knowledge that the previous operands are strings since the values are loaded
from the generator object. Adds a test for this case.

BUG=v8:6243

Change-Id: I1601a316e6efbed1c53486f1027cb0ea023ff030
Reviewed-on: https://chromium-review.googlesource.com/549301
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46243}

Uninitialized property accesses are replaced with SOFT deopts in
TurboFan, but uninitialized JSCall nodes are not, and instead they
just stick around and are also not being inlined because the heurstic
in TurboFan doesn't consider those candidates since their call frequency
is below the threshold. This unifies the behavior and also replaces
uninitialized calls with SOFT deopts, addressing some inconsistency in
optimization behavior as discovered by Brian White of Node for example
here: https://twitter.com/mscdexdotexe/status/879005026202640385

R=jarin@chromium.org
BUG=v8:4551, v8:5267

Review-Url: https://codereview.chromium.org/2956843002
Cr-Commit-Position: refs/heads/master@{#46231}

In edge cases such as the following, sloppy-mode block-scoped function
hoisting is expected to occur:

  eval(`
    with({a: 1}) {
      function a() {}
    }
  `)

In this case, there should be the equivalent of a var declaration
outside of the eval, which gets set to the value of the local function
a when the body of the with is executed.

Previously, the way that var declarations are hoisted out of eval
meant that the assignment to that var was an ordinary DYNAMIC_GLOBAL
assignment. However, such a lookup mode meant that the object in the
with scope received the assignment!

This patch fixes that error by marking the assignments produced by
the sloppy mode block scoped function hoisting desugaring so as to
generate a different runtime call which skips with scopes.

Bug: chromium:720247, v8:5135
Change-Id: Ie36322ddc9ca848bf680163e8c016f50d4597748
Reviewed-on: https://chromium-review.googlesource.com/529230
Commit-Queue: Daniel Ehrenberg <littledan@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46116}

Adds typed lowering of JSStringConcat to ConsString allocation if the
following conditions hold:
 - All concatinations will result in a ConsString of >= ConString::kMinLength
 - No concatinations will result in a empty string in the RHS unless there is
   a sequential string in the LHS.

This also means JSStringConcat needs an eager checkpoint since it can
deopt if throwing a RangeError when the string length protector is valid.

BUG=v8:6243

Change-Id: I01ca79f884df467c10f2c032c72d51b5199c1a3c
Reviewed-on: https://chromium-review.googlesource.com/526636
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46093}

ThrowIfHole bytecodes were handled by introducing deopt points to check
for a hole. To avoid deopt loops a hole check protector was used to
generate control flow if there was a deopt due to a hole. However, the
normal control flow version should be as fast as the deopt version
in general. The deopt version could potentially consume less compile time
but it may not be worth the complexity added. Hence simplifying it to
only construct the control flow.

Bug: v8:6383
Change-Id: Icace11f7a6e21e64e1cebd104496e3f559bc85f7
Reviewed-on: https://chromium-review.googlesource.com/525573Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45783}

Adds support for Speculatively lower ToPrimitiveToString to CheckString
where the type hint shows the value has always been a string.

BUG=v8:6243

Change-Id: I7f36deb8c2bc309e6d0546e099c76ac518c6be09
Reviewed-on: https://chromium-review.googlesource.com/521123
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45760}

Adds support for lowering of ToPrimitiveToString and StringConcat bytecodes
to the corresponding builtins. As part of this, moves the interpreter
implementation of these operations into the appropriate builtin generators
and add builtin support for them.

Also adds TailCallRuntimeN operator to code-assembler which enables tail calling
a runtime function when the arguments have already been pushed onto the stack.

BUG=v8:6243

Change-Id: Id5c851bc42e4ff490d9a23a8990ae331c7eac73e
Reviewed-on: https://chromium-review.googlesource.com/515362
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45756}

This CL implements general infrastructure for block coverage together with
initial support for if-statements.

Coverage output can be generated in lcov format by d8 as follows:

$ d8 --block-coverage --lcov=$(echo ~/simple-if.lcov) ~/simple-if.js
$ genhtml ~/simple-if.lcov -o ~/simple-if
$ chrome ~/simple-if/index.html

A high level overview of the implementation follows:

The parser now collects source ranges unconditionally for relevant AST nodes.
Memory overhead is very low and this seemed like the cleanest and simplest
alternative.

Bytecode generation uses these ranges to allocate coverage slots and insert
IncBlockCounter instructions (e.g. at the beginning of then- and else blocks
for if-statements). The slot-range mapping is generated here and passed on
through CompilationInfo, and is later accessible through the
SharedFunctionInfo.

The IncBlockCounter bytecode fetches the slot-range mapping (called
CoverageInfo) from the shared function info and simply increments the counter.
We don't collect native-context-specific counts as they are irrelevant to our
use-cases.

Coverage information is finally generated on-demand through Coverage::Collect.
The only current consumer is a d8 front-end with lcov-style output, but the
short-term goal is to expose this through the inspector protocol.

BUG=v8:6000
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_rel_ng

Review-Url: https://codereview.chromium.org/2882973002
Cr-Commit-Position: refs/heads/master@{#45737}

Introduces ThrowReferenceErrorIfHole / ThrowSuperNotCalledIfHole 
/ ThrowSuperAlreadyCalledIfNotHole bytecodes to handle hole checks.
In the bytecode-graph builder they are handled by introducing a deopt point
instead of adding explicit control flow. JumpIfNotHole / JumpIfNotHoleConstant
bytecodes are removed since they are no longer required.


Bug: v8:4280, v8:6383
Change-Id: I58b70c556b0ffa30e41a0cd44016874c3e9c5fe1
Reviewed-on: https://chromium-review.googlesource.com/509613
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45720}