Now that all 'const' declarations are of the ES2015 variety, the only
use of CONST_LEGACY is for function name bindings in sloppy mode
named function expressions.

This patch aims to delete all code meant to handle other cases, which
mostly had to do with hole initialization/hole checks. Since function
name bindings are initialized at entry to a function, it's impossible
to ever observe one in an uninitialized state.

To simplify the patch further, it removes the `IMPORT` VariableMode,
as it's not likely to be needed (IMPORT is identical to CONST for
the purpose of VariableMode).

Review URL: https://codereview.chromium.org/1895973002

Cr-Commit-Position: refs/heads/master@{#35632}

This patch correctly re-scopes inner scopes that can appear in do
expressions used as initializers to arrow parameters.

R=rossberg@chromium.org
BUG=v8:4904
LOG=N

Review URL: https://codereview.chromium.org/1887743002

Cr-Commit-Position: refs/heads/master@{#35542}

Annotate generator functions and loops therein with the number of contained
yields.  This information will eventually be used by the bytecode generator.

R=bmeurer@chromium.org
BUG=v8:4907
LOG=n

Review URL: https://codereview.chromium.org/1877403003

Cr-Commit-Position: refs/heads/master@{#35439}

The usage of __attribute__((format(x, y)) was either wrong or missing from multiple functions, leading to erroneous formats. This CL:

 - Imports PRINTF_FORMAT macro from Chrome's src/base/compiler-specific.h.
 - Uses it appropriately.
 - Imports Chrome's base/format_macros.h mainly to fix size_t formats (further cleanup could be done).
 - Fixes a bunch of incorrect formats.

Original CL: https://codereview.chromium.org/1869433004
Reverted in: https://codereview.chromium.org/1867383002
Reverted again in: https://codereview.chromium.org/1877823003

Reverts due to non-CQ bots:
  - First: v8_win_dbg, v8_win64_dbg, v8_mac_dbg
  - Second: gc mole (added to v8_linux_rel_ng for this patch)

R= jochen@chromium.org
TBR= ahaas@chromium.org,bmeurer@chromium.org,yangguo@chromium.org

Review URL: https://codereview.chromium.org/1872203005

Cr-Commit-Position: refs/heads/master@{#35423}

Review URL: https://codereview.chromium.org/1856643002

Cr-Commit-Position: refs/heads/master@{#35399}

Reason for revert:
Breaks gc mole:
https://build.chromium.org/p/client.v8/builders/V8%20Linux/builds/9421

Original issue's description:
> Fix printf formats
>
> The usage of __attribute__((format(x, y)) was either wrong or missing from multiple functions, leading to erroneous formats. This CL:
>
>  - Imports PRINTF_FORMAT macro from Chrome's src/base/compiler-specific.h.
>  - Uses it appropriately.
>  - Imports Chrome's base/format_macros.h mainly to fix size_t formats (further cleanup could be done).
>  - Fixes a bunch of incorrect formats.
>
> Original CL: https://codereview.chromium.org/1869433004
> Reverted in: https://codereview.chromium.org/1867383002
>
> R= jochen@chromium.org
> TBR= bmeurer@chromium.org, yangguo@chromium.org, ahaas@chromium.org
>
> Committed: https://crrev.com/bf505329288e1b75bab0e6800371a9aac40fa5cc
> Cr-Commit-Position: refs/heads/master@{#35394}

TBR=jochen@chromium.org,ahaas@chromium.org,bmeurer@chromium.org,yangguo@chromium.org,jfb@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/1877823003

Cr-Commit-Position: refs/heads/master@{#35396}

The usage of __attribute__((format(x, y)) was either wrong or missing from multiple functions, leading to erroneous formats. This CL:

 - Imports PRINTF_FORMAT macro from Chrome's src/base/compiler-specific.h.
 - Uses it appropriately.
 - Imports Chrome's base/format_macros.h mainly to fix size_t formats (further cleanup could be done).
 - Fixes a bunch of incorrect formats.

Original CL: https://codereview.chromium.org/1869433004
Reverted in: https://codereview.chromium.org/1867383002

R= jochen@chromium.org
TBR= bmeurer@chromium.org, yangguo@chromium.org, ahaas@chromium.org

Review URL: https://codereview.chromium.org/1877453002

Cr-Commit-Position: refs/heads/master@{#35394}

Revert of Fix printf formats (patchset #8 id:140001 of https://codereview.chromium.org/1869433004/ )

Reason for revert:
One small issue easily fixed here: https://codereview.chromium.org/1867333003/

But it looks like MSVS 2013 doesn't like some of the formats and exists with the unhelpful:
Stderr:
f:\dd\vctools\crt\crtw32\stdio\output.c(1125) : Assertion failed: ("Incorrect
format specifier", 0)

It's easier to revert for now, I'll dig more into the docs:
https://msdn.microsoft.com/en-us/library/56e442dc(v=vs.120).aspx
https://msdn.microsoft.com/en-us/library/tcxf1dw6(v=vs.120).aspx

And then resubmit, making sure I run these bots.

Original issue's description:
> Fix printf formats
>
> The usage of __attribute__((format(x, y)) was either wrong or missing from multiple functions, leading to erroneous formats. This CL:
>
>  - Imports PRINTF_FORMAT macro from Chrome's src/base/compiler-specific.h.
>  - Uses it appropriately.
>  - Imports Chrome's base/format_macros.h mainly to fix size_t formats (further cleanup could be done).
>  - Fixes a bunch of incorrect formats.
>
> R= jochen@chromium.org, bmeurer@chromium.org, yangguo@chromium.org, ahaas@chromium.org
>
> Committed: https://crrev.com/6ebf9fbb93d31f9be41156a3325d58704ed4933d
> Cr-Commit-Position: refs/heads/master@{#35365}

TBR=jochen@chromium.org,bmeurer@chromium.org,yangguo@chromium.org,ahaas@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/1867383002

Cr-Commit-Position: refs/heads/master@{#35366}

The usage of __attribute__((format(x, y)) was either wrong or missing from multiple functions, leading to erroneous formats. This CL:

 - Imports PRINTF_FORMAT macro from Chrome's src/base/compiler-specific.h.
 - Uses it appropriately.
 - Imports Chrome's base/format_macros.h mainly to fix size_t formats (further cleanup could be done).
 - Fixes a bunch of incorrect formats.

R= jochen@chromium.org, bmeurer@chromium.org, yangguo@chromium.org, ahaas@chromium.org

Review URL: https://codereview.chromium.org/1869433004

Cr-Commit-Position: refs/heads/master@{#35365}

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1857703002

Cr-Commit-Position: refs/heads/master@{#35228}

The parser uses a try-catch in order to record when the client of an iterator
throws.  The exception then used to get rethrown via 'throw', which
unfortunately resulted in the original exception message object getting
overwritten.

This CL solves this as follows:
- add a clear_pending_message flag to TryCatchStatement (set to true in normal
  cases),
- set clear_pending_message to false for the TryCatchStatement used in iterator
  finalization
- change full-codegen, turbofan, and the interpreter to emit the ClearPendingMessage call
  only when the flag is set,
- replace 'throw' with '%ReThrow' in the iterator finalization code, thus
  reusing the (not-cleared) pending message

R=littledan@chromium.org, mstarzinger@chromium.org, yangguo@chromium.org
BUG=v8:4875
LOG=n

Review URL: https://codereview.chromium.org/1842953003

Cr-Commit-Position: refs/heads/master@{#35226}

R=bmeurer@chromium.org, cbruni@chromium.org, ulan@chromium.org
BUG=chromium:124206,chromium:569811
LOG=N

Review URL: https://codereview.chromium.org/1834633003

Cr-Commit-Position: refs/heads/master@{#35145}

Now that ES2015 const has shipped, in Chrome 49, legacy const declarations
are no more. This lets us remove a bunch of code from many parts of the
codebase.

In this patch, I remove parser support for generating legacy const variables
from const declarations. This also removes the special "illegal declaration"
bit from Scope, which has ripples into all compiler backends.

Also gone are any tests which relied on legacy const declarations.

Note that we do still generate a Variable in mode CONST_LEGACY in one case:
function name bindings in sloppy mode. The likely fix there is to add a new
Variable::Kind for this case and handle it appropriately for stores in each
backend, but I leave that for a later patch to make this one completely
subtractive.

Review URL: https://codereview.chromium.org/1819123002

Cr-Commit-Position: refs/heads/master@{#35002}

This removes the Isolate argument from the IsLiteralCompareUndefined
predicate as it is no longer required to determine the answer.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/1814823005

Cr-Commit-Position: refs/heads/master@{#34902}

Just sayin'.

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1813913004

Cr-Commit-Position: refs/heads/master@{#34901}

If the variable is unallocated, say so.

This CL also fixes the return value of FormatSlotNode.

R=mvstanton@chromium.org
TBR=rossberg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1806883003

Cr-Commit-Position: refs/heads/master@{#34846}

This should recover regression caused by 7f11fba7 (https://codereview.chromium.org/1739233002).

TBR=bmeurer@chromium.org
BUG=chromium:592692, chromium:595265
LOG=N

Review URL: https://codereview.chromium.org/1807913002

Cr-Commit-Position: refs/heads/master@{#34824}

This part of Scope has existed since V8's initial check in, but from what
I can tell it's not required to implement "with". The only tests that
depend upon it are tests of the debugger and the Scope mirrors, but the
resulting test behavior after removing the bit still seems perfectly
reasonable to me. In fact, with the included fix for scope name collection,
the scope mirror is actually improved with this change.

As a bi-product, this fixes the attached bug, about the contains_with
bit having inconsistent values in some arrow function compilation
scenarios.

BUG=chromium:592353
LOG=n
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1804783002

Cr-Commit-Position: refs/heads/master@{#34802}

This should recover a part of the regression caused by 7f11fba7 (https://codereview.chromium.org/1739233002).

BUG=chromium:592692
LOG=N

Review URL: https://codereview.chromium.org/1793293003

Cr-Commit-Position: refs/heads/master@{#34783}

R=mstarzinger@chromium.org,bmeurer@chromium.org,adamk@chromium.org
BUG=v8:3956
LOG=Y

Review URL: https://codereview.chromium.org/1773653002

Cr-Commit-Position: refs/heads/master@{#34669}

This mechanism was used to ensure that functions ended up as constants on the map of prototypes defined using object literals, e.g.,:

function.prototype = {
  method: function() { ... }
}

Nowadays we treat prototypes specially, and make all their functions constants when an object turns prototype. Hence this special custom code isn't necessary anymore.

This also affects boilerplates that do not become prototypes. Their functions will not be constants but fields instead. Calling their methods will slow down. However, multiple instances of the same boilerplate will stay monomorphic. We'll have to see what the impact is for such objects, but preliminary benchmarks do not show this as an important regression.

BUG=chromium:593008
LOG=n

Review URL: https://codereview.chromium.org/1772423002

Cr-Commit-Position: refs/heads/master@{#34602}

BUG=

Review URL: https://codereview.chromium.org/1768203002

Cr-Commit-Position: refs/heads/master@{#34582}

HInvokeFunction and HApplyArguments instructions now support tail calling.

Inlining of calls at tail position is not supported yet and therefore still disabled.

The tail-call-megatest was modified so that the usages of "arguments" object do not disable Crankshaft.

TBR=bmeurer@chromium.org
BUG=v8:4698
LOG=N

Review URL: https://codereview.chromium.org/1760253003

Cr-Commit-Position: refs/heads/master@{#34542}

Now there is just one kind, corresponding to what was called "initial" before.
Replacement for "suspend": when the parser sees a yield in JS code, it
will turn it into a Yield node but wrap its argument in an iterator result
object.  Replacement for "final": the parser simply inserts a return statement
instead.

R=littledan@chromium.org, mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1751613004

Cr-Commit-Position: refs/heads/master@{#34515}

Crankshaft can't track operand/environment changes between arbitrary statements.
We need that to fully support do-expressions. Instead, a subset is supported
by bailing out on break statements, continue statements, and if we've made an
OSR entry within a do-expression.

This partial support is a good idea because do-expressions are a useful tool
for desugaring during parsing.

BUG=
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/1769463002

Cr-Commit-Position: refs/heads/master@{#34491}

blink-side cl: https://codereview.chromium.org/1653053002/

BUG=327092
LOG=Y

Review URL: https://codereview.chromium.org/1653083002

Cr-Commit-Position: refs/heads/master@{#34417}

R=bmeurer@chromium.org
BUG=v8:3956
LOG=n

Review URL: https://codereview.chromium.org/1731063007

Cr-Commit-Position: refs/heads/master@{#34398}

The "each" slot is only actually used by ForIn, so this simply cleans
up a TODO of mine and removes an IsForOfStatement() call.

Review URL: https://codereview.chromium.org/1742013002

Cr-Commit-Position: refs/heads/master@{#34369}

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/1748613002

Cr-Commit-Position: refs/heads/master@{#34358}

R=bmeurer@chromium.org
BUG=v8:3956
LOG=n

Review URL: https://codereview.chromium.org/1734243004

Cr-Commit-Position: refs/heads/master@{#34333}

BUG=
R=littledan@chromium.org

Review URL: https://codereview.chromium.org/1735033002

Cr-Commit-Position: refs/heads/master@{#34294}

This is a rework of the instanceof operator to support ES6 semantics
(as per section 12.10.4 of the spec:
https://tc39.github.io/ecma262/#sec-instanceofoperator).

It's behind flag --harmony-instanceof for now, which is turned on for staging.

BUG=v8:4447
LOG=N

Review URL: https://codereview.chromium.org/1692713005

Cr-Commit-Position: refs/heads/master@{#34170}

of non-pattern expressions, according to the (internally circulated)
design document.  Details to be provided here.

1.  RewritableAssignmentExpression has been renamed to RewritableExpression.
    It is a wrapper for AST nodes that wait for some potential rewriting
    (that may or may not happen).  Also, Is... and As... macros now see
    through RewritableExpressions.

2.  The function state keeps a list of rewritable expressions that must be
    rewritten only if they are used as non-pattern expressions.

3.  Expression classifiers are now templates, parameterized by parser
    traits.  They keep some additional state: a pointer to the list of
    non-pattern rewritable expressions.  It is important that expression
    classifiers be used strictly in a stack fashion, from now on.

4.  The RewriteNonPattern function has been simplified.

BUG=chromium:579913
LOG=N

Committed: https://crrev.com/7f5c864a6faf2b957b7273891e143b9bde35487c
Cr-Commit-Position: refs/heads/master@{#34154}

Review URL: https://codereview.chromium.org/1702063002

Cr-Commit-Position: refs/heads/master@{#34162}

Another attempt, after the failing test (flushed bug) has been disabled
in chromium (https://codereview.chromium.org/1710353002).

Review URL: https://codereview.chromium.org/1713033002

Cr-Commit-Position: refs/heads/master@{#34159}

Revert of Non-pattern rewriting revisited (patchset #3 id:40001 of https://codereview.chromium.org/1702063002/ )

Reason for revert:
[Sheriff] This makes jsfunfuzz unhappy:
https://build.chromium.org/p/client.v8/builders/V8%20Fuzzer/builds/7681

Original issue's description:
> This patch implements an alternative approach to the rewriting
> of non-pattern expressions, according to the (internally circulated)
> design document.  Details to be provided here.
>
> 1.  RewritableAssignmentExpression has been renamed to RewritableExpression.
>     It is a wrapper for AST nodes that wait for some potential rewriting
>     (that may or may not happen).  Also, Is... and As... macros now see
>     through RewritableExpressions.
>
> 2.  The function state keeps a list of rewritable expressions that must be
>     rewritten only if they are used as non-pattern expressions.
>
> 3.  Expression classifiers are now templates, parameterized by parser
>     traits.  They keep some additional state: a pointer to the list of
>     non-pattern rewritable expressions.  It is important that expression
>     classifiers be used strictly in a stack fashion, from now on.
>
> 4.  The RewriteNonPattern function has been simplified.
>
> BUG=chromium:579913
> LOG=N
>
> Committed: https://crrev.com/7f5c864a6faf2b957b7273891e143b9bde35487c
> Cr-Commit-Position: refs/heads/master@{#34154}

TBR=rossberg@chromium.org,bmeurer@chromium.org,titzer@chromium.org,nikolaos@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:579913

Review URL: https://codereview.chromium.org/1712203002

Cr-Commit-Position: refs/heads/master@{#34158}

of non-pattern expressions, according to the (internally circulated)
design document.  Details to be provided here.

1.  RewritableAssignmentExpression has been renamed to RewritableExpression.
    It is a wrapper for AST nodes that wait for some potential rewriting
    (that may or may not happen).  Also, Is... and As... macros now see
    through RewritableExpressions.

2.  The function state keeps a list of rewritable expressions that must be
    rewritten only if they are used as non-pattern expressions.

3.  Expression classifiers are now templates, parameterized by parser
    traits.  They keep some additional state: a pointer to the list of
    non-pattern rewritable expressions.  It is important that expression
    classifiers be used strictly in a stack fashion, from now on.

4.  The RewriteNonPattern function has been simplified.

BUG=chromium:579913
LOG=N

Review URL: https://codereview.chromium.org/1702063002

Cr-Commit-Position: refs/heads/master@{#34154}

Various syntactic forms now cause functions to have names where they
didn't before. Per the upcoming changes to the toString spec, only
a name that was literally part of a function's expression or declaration
is meant to be reflected in toString. This also happens to be the same
set of names that V8 currently outputs (without the --harmony-function-name
flag).

This required distinguishing anonymous FunctionExpressions from other sorts
of function definitions (like methods and getters/setters) in the AST, parser,
and at runtime.

The patch also takes the opportunity to remove one more argument (and enum)
from FunctionLiteral, as well as adding a special factory method for the
case of a FunctionLiteral representing toplevel or eval'd code.

BUG=v8:4760
LOG=n

Review URL: https://codereview.chromium.org/1712833002

Cr-Commit-Position: refs/heads/master@{#34132}

This frees up one bit in FunctionKind, which I plan to make slightly
more syntactic info about functions available in SharedFunctionInfo
(needed for ES2015 Function.name support).

BUG=v8:3956, v8:4760
LOG=n

Review URL: https://codereview.chromium.org/1704223002

Cr-Commit-Position: refs/heads/master@{#34125}

BUG=v8:4698
LOG=N

Review URL: https://codereview.chromium.org/1713533002

Cr-Commit-Position: refs/heads/master@{#34115}

Implements iterator finalisation by desugaring for-of loops with an additional try-finally wrapper. See comment in parser.cc for details.

Also improved some AST printing facilities while there.

@Ross, I had to disable the bytecode generation test for for-of, because it got completely out of hand after this change (the new bytecode has 150+ lines). See the TODO that I assigned to you.

Patch set 1 is WIP patch by Georg (http://crrev.com/1695583003), patch set 2 relative changes.

@Georg, FYI, I changed the following:

- Moved try-finally out of the loop body, for performance, and in order to be able to handle `continue` correctly.
- Fixed scope management in ParseForStatement, which was the cause for the variable allocation failure.
- Fixed pre-existing zone initialisation bug in rewriter, which caused the crashes.
- Enabled all tests, adjusted a few others, added a couple more.

BUG=v8:2214
LOG=Y

Review URL: https://codereview.chromium.org/1695393003

Cr-Commit-Position: refs/heads/master@{#34111}