After updating our bots to use GCC 7.4, we do not need to support
incomplete C++14 support any more. In particular, we can assume
complete c++14 constexpr support now.

This CL removes the V8_HAS_CXX14_CONSTEXPR and CONSTEXPR_DCHECK macros.
The CONSTEXPR_DCHECKs are replaced by DCHECK and friend, or
STATIC_ASSERT where possible.

R=jgruber@chromium.org, leszeks@chromium.org, mlippautz@chromium.org

Bug: v8:9686, v8:11384
Change-Id: I3a8769a0f54da7eb2cacc37ee23e5c97092e3051
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2876847Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74486}

We are working on getting Liftoff feature complete. Eventually, bailout
should only happen if experimental features are enabled. Until we are
there, we also need to allow some more bailouts, which should be removed
in the near future.

This CL adds a check for expected bailout reasons. The new function
serves as a burndown list of issues to be fixed.

Drive-by: Make some methods constexpr such that they can be used in
static assertions.

R=ahaas@chromium.org

Change-Id: I5d3cd8f49a30d01f89ac6cf5321e1314b63eba40
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2629513
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72127}

Introduced in https://crrev.com/c/2250243.

CONSTEXPR_DCHECK(cond) replaces the longer

 #if V8_HAS_CXX14_CONSTEXPR
     DCHECK(cond);
 #endif

pattern.

Change-Id: I636e5b4b40bffb29b2e82c81285b2ef78a822745
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2250244Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68402}

This is a reland of 0dc598df

Original change's description:
> [wasm] Refactor callback triggering
> 
> 1) Instead of passing three boolean values to |TriggerCallbacks|, pass
>    one EnumSet which contains all events to trigger.
> 2) Remember which events already happened, to avoid triggering them
>    again.
> 3) Compute triggered events once after the loop in |OnFinishedUnits|,
>    instead of checking for every finished unit.
> 4) When a new callback is registered, trigger all previous events
>    immediately. This solves issue v8:10217.
> 5) Replace |NotifyTopTierReady| by |AddCallback| which is identical now.
> 6) Do not call |OnFinishedJSToWasmWrapperUnits| if no wrappers were
>    compiled (this is a minor performance optimization; we save taking
>    and releasing a lock).
> 7) Drive-by: Make the |EnumSet| constructor really constexpr (by making
>    |Mask| constexpr).
> 
> R=ahaas@chromium.org
> 
> Bug: v8:10217
> Change-Id: Ib3688a1687ad7b523e90efd73f4073e9f1193016
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2072737
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#66459}

Bug: v8:10217
Change-Id: I9f7ca424fa7f1d0379dabe230bebf62522dfc857
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2074501Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66468}

This reverts commit 0dc598df.

Reason for revert: Fails the wasm-cache-test blink test.

Original change's description:
> [wasm] Refactor callback triggering
> 
> 1) Instead of passing three boolean values to |TriggerCallbacks|, pass
>    one EnumSet which contains all events to trigger.
> 2) Remember which events already happened, to avoid triggering them
>    again.
> 3) Compute triggered events once after the loop in |OnFinishedUnits|,
>    instead of checking for every finished unit.
> 4) When a new callback is registered, trigger all previous events
>    immediately. This solves issue v8:10217.
> 5) Replace |NotifyTopTierReady| by |AddCallback| which is identical now.
> 6) Do not call |OnFinishedJSToWasmWrapperUnits| if no wrappers were
>    compiled (this is a minor performance optimization; we save taking
>    and releasing a lock).
> 7) Drive-by: Make the |EnumSet| constructor really constexpr (by making
>    |Mask| constexpr).
> 
> R=​ahaas@chromium.org
> 
> Bug: v8:10217
> Change-Id: Ib3688a1687ad7b523e90efd73f4073e9f1193016
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2072737
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#66459}

TBR=ahaas@chromium.org,clemensb@chromium.org

Change-Id: I564b053e898db5f7b51cefa4626c0625a225c89a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:10217
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2074638Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66461}

1) Instead of passing three boolean values to |TriggerCallbacks|, pass
   one EnumSet which contains all events to trigger.
2) Remember which events already happened, to avoid triggering them
   again.
3) Compute triggered events once after the loop in |OnFinishedUnits|,
   instead of checking for every finished unit.
4) When a new callback is registered, trigger all previous events
   immediately. This solves issue v8:10217.
5) Replace |NotifyTopTierReady| by |AddCallback| which is identical now.
6) Do not call |OnFinishedJSToWasmWrapperUnits| if no wrappers were
   compiled (this is a minor performance optimization; we save taking
   and releasing a lock).
7) Drive-by: Make the |EnumSet| constructor really constexpr (by making
   |Mask| constexpr).

R=ahaas@chromium.org

Bug: v8:10217
Change-Id: Ib3688a1687ad7b523e90efd73f4073e9f1193016
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2072737
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66459}

This extends EnumSet by
1) adding element-wise operations (without first creating an EnumSet of
   that element in the caller),
2) adding arithmetic assignment operators, and
3) adding a subtraction operation which removes all elements in another
   EnumSet, or a single element.

R=mlippautz@chromium.org

Change-Id: Ibe694e9e111e506ad09cf9729fa0b0ba38430b79
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2071874
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66451}

EnumSet hold a single integral field, hence it should be passed by
value. All users already do this, we are just inconsistent within the
declaration of EnumSet itself.

R=mlippautz@chromium.org

Change-Id: Ic2cac35fbd8fe3e98c1fe135bd334547dca30ab5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2071872Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66447}

Make WasmFeatures a proper class which uses an EnumSet under the hood.
This way, it inherits all behaviour of EnumSet like comparison, merge,
etc.
Accesses change from being simple field access into the struct to
actually bit tests in the EnumSet.

R=mstarzinger@chromium.org

Bug: v8:10019
Change-Id: I768f92b90ac0294156f4482defba5ce00bc70165
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1934334
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65184}

After moving to its own header, this CL cleans up some parts of the
interface. It fixes names and const-declarations of simple accessors,
and adds a named constructor to make it explicit that an EnumSet should
be constructed from an integral value.
Also refactor the use in cctest.h to have less statically declared
constants. Instead, just create the set of extensions in the individual
tests.

R=titzer@chromium.org

Bug: v8:8562
Change-Id: I6178d1aba25afa1d7f54c29ccf81505c165e7cd3
Reviewed-on: https://chromium-review.googlesource.com/c/1409366
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58862}

EnumSet currently lives in src/utils.h, which is a conglomerate of many
different helper functions and classes. In order to remove unneeded
include, move the EnumSet to its own header.

R=titzer@chromium.org

Bug: v8:7490, v8:8562
Change-Id: I979814167e87b914e9807b03e342d8b34e514331
Reviewed-on: https://chromium-review.googlesource.com/c/1409430
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58818}