This adds the basics necessary to support float32 operations in TurboFan.
The actual functionality required to detect safe float32 operations will
be added based on this later. Therefore this does not affect production
code except for some cleanup/refactoring.

In detail, this patchset contains the following features:
- Add support for float32 operations to arm, arm64, ia32 and x64
  backends.
- Add float32 machine operators.
- Add support for float32 constants to simplified lowering.
- Handle float32 representation for phis in simplified lowering.

In addition, contains the following (related) cleanups:
- Fix/unify naming of backend instructions.
- Use AVX comparisons when available.
- Extend ArchOpcodeField to 9 bits (required for arm64).
- Refactor some code duplication in instruction selectors.

BUG=v8:3589
LOG=n
R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/1044793002

Cr-Commit-Position: refs/heads/master@{#27509}

No compiler support for now (BTW: %_NewString, doesn't have that,
either), inline allocation will come later. Hopefully the last
intrisic to add for a StringAddStub POC...

Review URL: https://codereview.chromium.org/1041723002

Cr-Commit-Position: refs/heads/master@{#27508}

And reland "Use a slot that is located on a heap page when removing
invalid entries from the SlotsBuffer."

This reverts commits de018fbd and
d23a9f7a.

Reason for relanding: looking fine on Canary, let's get these fixes back in.

BUG=chromium:454297,chromium:470801
LOG=y
TBR=ishell@chromium.org

Review URL: https://codereview.chromium.org/1043703003

Cr-Commit-Position: refs/heads/master@{#27507}

Port 019096f8

Original commit message:

R=mbrandy@us.ibm.com

BUG=

Review URL: https://codereview.chromium.org/1036273003

Cr-Commit-Position: refs/heads/master@{#27506}

This avoid to depend on MiscField to be big enough to hold the offset/size.
This patch also remove the Arm64PokePair which is no longer used.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1039753002

Cr-Commit-Position: refs/heads/master@{#27505}

We do not need to step one instruction further since we do not use Jr to J
optimization anymore for mips64.

TEST=
BUG=

Review URL: https://codereview.chromium.org/1041833002

Cr-Commit-Position: refs/heads/master@{#27504}

This CL also adds useful machinery that helps triggering incremental write barriers.

BUG=chromium:469146
LOG=Y

Review URL: https://codereview.chromium.org/1039733003

Cr-Commit-Position: refs/heads/master@{#27503}

On 'debugger' statement, if anything in debugger calls 'EnsureDebugInfo'
on a function, EnsureDebugInfo would compile and substitute code without
debug break slots. This causes weird behavior later when stepping fails
to work (see added test as an example).
This fix is to make sure the debugger is prepared for breakpoints in
that case as well.

Also adds extra testing for bug 468661.

R=yangguo@chromium.org,yurys@chromium.orh
BUG=v8:3990,chromium:468661
LOG=N

Review URL: https://codereview.chromium.org/1032353002

Cr-Commit-Position: refs/heads/master@{#27502}

R=jochen@chromium.org

Review URL: https://codereview.chromium.org/1041743002

Cr-Commit-Position: refs/heads/master@{#27501}

This fixes simulated debug-mode failures in the following tests:
  mjsunit/regexp-stack-overflow
  mjsunit/regress/regress-crbug-467047

R=mbrandy@us.ibm.com

BUG=

Review URL: https://codereview.chromium.org/1035003002

Cr-Commit-Position: refs/heads/master@{#27500}

TEST=mjsunit/compiler/regress-3, osr-maze1
BUG=

Review URL: https://codereview.chromium.org/1038173003

Cr-Commit-Position: refs/heads/master@{#27499}

R=verwaest@chromium.org
BUG=466084
LOG=N

Review URL: https://codereview.chromium.org/1037213002

Cr-Commit-Position: refs/heads/master@{#27498}

Review URL: https://codereview.chromium.org/1031383002

Cr-Commit-Position: refs/heads/master@{#27497}

Convert a perf trybot JSON file into a pleasing HTML page. It can read
from standard input or via the --filename option. Examples:

  cat results.json | perf-to-html.py --title "ia32 results"
  perf-to-html.py -f results.json -t "ia32 results" -o results.html

Options:
  -h, --help            show this help message and exit
  -f FILENAME, --filename=FILENAME
                        Specifies the filename for the JSON results rather
                        than reading from stdin.
  -t TITLE, --title=TITLE
                        Optional title of the web page.
  -o OUTPUT, --output=OUTPUT
                        Write html output to this file rather than stdout.

R=machenbach@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1033603004

Cr-Commit-Position: refs/heads/master@{#27496}

Revert of [turbofan][arm64] Match fneg for -0.0 - x pattern. (patchset #1 id:1 of https://codereview.chromium.org/1013743006/)

Reason for revert:
Revert due to crash.

Original issue's description:
> [turbofan][arm64] Match fneg for -0.0 - x pattern.
>
> Note that this patch add an extra bit to the ArchOpcodeField.
>
> R=bmeurer@chromium.org
>
> Committed: https://crrev.com/fe7441225100660d01e66ce3bcaefe368f62df81
> Cr-Commit-Position: refs/heads/master@{#27494}

TBR=bmeurer@chromium.org,baptiste.afsa@arm.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1041633002

Cr-Commit-Position: refs/heads/master@{#27495}

Note that this patch add an extra bit to the ArchOpcodeField.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1013743006

Cr-Commit-Position: refs/heads/master@{#27494}

The current GC idle time handling heuristics are getting too complicated. Moreover, with longer idle time we are getting more full garbage collections. This CL shrinks the idle round window and reduces complexity in the case where we cause a full garbage collection.

BUG=chromium:468554
LOG=n

Review URL: https://codereview.chromium.org/1024043003

Cr-Commit-Position: refs/heads/master@{#27493}

BUG=

Review URL: https://codereview.chromium.org/1039153002

Cr-Commit-Position: refs/heads/master@{#27492}

Revert of Reland "Filter invalid slots out from the SlotsBuffer after marking." (patchset #2 id:2 of https://codereview.chromium.org/1032833002/)

Reason for revert:
Reverting risky GC changes that block v8 roll.

Original issue's description:
> Reland "Filter invalid slots out from the SlotsBuffer after marking."
>
> > There are two reasons that could cause invalid slots appearance in SlotsBuffer:
> > 1) If GC trims "tail" of an array for which it has already recorded a slots and then migrate another object to the "tail".
> > 2) Tagged slot could become a double slot after migrating of an object to another map with "shifted" fields (for example as a result of generalizing immutable data property to a data field).
>
> > This CL also adds useful machinery that helps triggering incremental write barriers.
>
> > BUG=chromium:454297
> > LOG=Y
>
> NOTRY=true
>
> Committed: https://crrev.com/f86aadd1d45c756467dff8e08a055b462d7a060b
> Cr-Commit-Position: refs/heads/master@{#27433}

TBR=machenbach@chromium.org,ulan@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1041593002

Cr-Commit-Position: refs/heads/master@{#27491}

Revert of Use a slot that is located on a heap page when removing invalid entries from the SlotsBuffer. (patchset #1 id:1 of https://codereview.chromium.org/1020853022/)

Reason for revert:
Reverting risky GC changes that block v8 roll.

Original issue's description:
> Use a slot that is located on a heap page when removing invalid entries from the SlotsBuffer.
>
> BUG=chromium:470801
> LOG=Y
>
> Committed: https://crrev.com/2f3a42f9a1d66ffc9d260d9700ff831c3aa1cd41
> Cr-Commit-Position: refs/heads/master@{#27467}

TBR=hpayer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:470801

Review URL: https://codereview.chromium.org/1033163002

Cr-Commit-Position: refs/heads/master@{#27490}

Use 64-bit load.

BUG=

Review URL: https://codereview.chromium.org/1037863003

Cr-Commit-Position: refs/heads/master@{#27489}

Fixes these tests in PPC,debug,non-sim

mjsunit/compiler/osr-maze1
mjsunit/compiler/regress-3
mjsunit/regress/regress-crbug-173907
mjsunit/regress/regress-crbug-173907b

R=mbrandy@us.ibm.com

BUG=

Review URL: https://codereview.chromium.org/1038923003

Cr-Commit-Position: refs/heads/master@{#27488}

R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/1034153003

Cr-Commit-Position: refs/heads/master@{#27487}

Port ebc51674

Original commit message:

R=mbrandy@us.ibm.com

BUG=

Review URL: https://codereview.chromium.org/1016003005

Cr-Commit-Position: refs/heads/master@{#27486}

R=ulan@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1032373002

Cr-Commit-Position: refs/heads/master@{#27485}

  This change comes from a6940f7a.

BUG=

Review URL: https://codereview.chromium.org/1031253005

Cr-Commit-Position: refs/heads/master@{#27484}

This reverts commit 89ba65fd.

Reason: crash in v8.detached_context_age_in_gc benchmark.

BUG=chromium:450824
LOG=NO
NOTRY=true
NOTREECHECKS=true
TBR=hpayer@chromium.org

Review URL: https://codereview.chromium.org/1034203002

Cr-Commit-Position: refs/heads/master@{#27483}

R=verwaest@chromium.org
BUG=468451
LOG=N

Review URL: https://codereview.chromium.org/1036743004

Cr-Commit-Position: refs/heads/master@{#27482}

The aforementioned predicate reported a JSFunction that was marked for
optimization as already compiled. This in turn also prevented us from
being aggressive about FLAG_always_opt treatment.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/1019293003

Cr-Commit-Position: refs/heads/master@{#27481}

BUG=

Review URL: https://codereview.chromium.org/1019923004

Cr-Commit-Position: refs/heads/master@{#27480}

We want to verify that we always overwrite heap objects with heap
objects, and non-heap objects with non-heap objects

BUG=chromium:452095
R=hpayer@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/1035763002

Cr-Commit-Position: refs/heads/master@{#27479}

port 38a719f9  (r27440)

original commit message:

    This switches full-codegen to no longer push and pop StackHandler
    markers onto the operand stack, but relies on a range-based handler
    table instead. We only use StackHandlers in JSEntryStubs to mark the
    transition from C to JS code.

    Note that this makes deoptimization and OSR from within any try-block
    work out of the box, makes the non-exception paths faster and should
    overall be neutral on the memory footprint (pros).

    On the other hand it makes the exception paths slower and actually
    throwing and exception more expensive (cons).

BUG=

Review URL: https://codereview.chromium.org/1030283003

Cr-Commit-Position: refs/heads/master@{#27478}

Only one FrameInspector can be active at a time on any given stack,
this ensures that it's lifetime is sufficiently scoped.

R=yangguo@chromium.org
TEST=mjsunit/regress/regress-crbug-259300

Review URL: https://codereview.chromium.org/1034743002

Cr-Commit-Position: refs/heads/master@{#27477}

BUG=none
R=hpayer@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/1032963002

Cr-Commit-Position: refs/heads/master@{#27476}

R=jochen@chromium.org, erikcorry@chromium.org

BUG=

Review URL: https://codereview.chromium.org/998253006

Cr-Commit-Position: refs/heads/master@{#27475}

This variant avoids a constant pool entry, which can be problematic
when LTO'ing. It is also slightly shorter.

R=bmeurer@chromium.org,Jacob.Bramley@arm.com
BUG=chromium:453195
LOG=n

Review URL: https://codereview.chromium.org/986643004

Cr-Commit-Position: refs/heads/master@{#27474}

Instead of CanRetainOtherContext, we now manually blacklist all access-checked objects.

BUG=

Review URL: https://codereview.chromium.org/1020803004

Cr-Commit-Position: refs/heads/master@{#27473}

Revert of Revert of Debugger: deduplicate shared function info when setting script break points. (patchset #1 id:1 of https://codereview.chromium.org/999273003/)

Reason for revert:
Reland since the failure has been fixed in https://codereview.chromium.org/1035523005/

Original issue's description:
> Revert of Debugger: deduplicate shared function info when setting script break points. (patchset #4 id:60001 of https://codereview.chromium.org/998253005/)
>
> Reason for revert:
> Code caching failures.
>
> Original issue's description:
> > Debugger: deduplicate shared function info when setting script break points.
> >
> > Also fix Debug.showBreakPoints for multiple break points at the same location.
> >
> > BUG=v8:3960
> > LOG=N
> >
> > Committed: https://crrev.com/73b17a71a22564c0b66d9aa7c00948c748f5b290
> > Cr-Commit-Position: refs/heads/master@{#27444}
>
> TBR=mstarzinger@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:3960
>
> Committed: https://crrev.com/9b29d008dfcc00bf56be8040add1d2c5e404673b
> Cr-Commit-Position: refs/heads/master@{#27448}

TBR=mstarzinger@chromium.org
BUG=v8:3960
LOG=N

Review URL: https://codereview.chromium.org/1037013002

Cr-Commit-Position: refs/heads/master@{#27472}

R=jochen@chromium.org

Review URL: https://codereview.chromium.org/1035523005

Cr-Commit-Position: refs/heads/master@{#27471}

BUG=

Review URL: https://codereview.chromium.org/1021713005

Cr-Commit-Position: refs/heads/master@{#27470}