Commit Graph

183 Commits

Author SHA1 Message Date
Marja Hölttä
82e43bfed8 [parser] Skipping inner funcs: produce the same scopes / variables for parameters (part 1).
This CL covers only the very simple cases.

BUG=v8:5516
R=vogelheim@chromium.org

Change-Id: Ib6ddc90cbcf1c923a7b72493cfd029cfa835462b
Reviewed-on: https://chromium-review.googlesource.com/440246
Reviewed-by: Daniel Vogelheim <vogelheim@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43086}
2017-02-10 09:18:40 +00:00
hablich
395dfc073e Reland of land: [Parse] ParseInfo owns the parsing Zone. (patchset #1 id:1 of https://codereview.chromium.org/2683733002/ )
Reason for revert:
False alarm, bot hiccup

Original issue's description:
> Revert of Reland: [Parse] ParseInfo owns the parsing Zone. (patchset #7 id:140001 of https://codereview.chromium.org/2632123006/ )
>
> Reason for revert:
> Speculative revert because of revert needed for https://codereview.chromium.org/2632123006
>
> Original issue's description:
> > Reland: [Parse] ParseInfo owns the parsing Zone.
> >
> > Moves ownership of the parsing Zone to ParseInfo with a shared_ptr. This is
> > in preperation for enabling background compilation jobs for inner functions
> > share the AST in the outer-function's parse zone memory (read-only), with the
> > and zone being released when all compilation jobs have completed.
> >
> > BUG=v8:5203,v8:5215
> >
> > Review-Url: https://codereview.chromium.org/2632123006
> > Cr-Original-Commit-Position: refs/heads/master@{#42993}
> > Committed: 14fb337200
> > Review-Url: https://codereview.chromium.org/2632123006
> > Cr-Commit-Position: refs/heads/master@{#42996}
> > Committed: 9e7d5a6065
>
> TBR=marja@chromium.org,mstarzinger@chromium.org,ahaas@chromium.org,verwaest@chromium.org,rmcilroy@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:5203,v8:5215
>
> Review-Url: https://codereview.chromium.org/2683733002
> Cr-Commit-Position: refs/heads/master@{#43008}
> Committed: 9fe08ec067

TBR=marja@chromium.org,mstarzinger@chromium.org,ahaas@chromium.org,verwaest@chromium.org,rmcilroy@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5203,v8:5215

Review-Url: https://codereview.chromium.org/2679303003
Cr-Commit-Position: refs/heads/master@{#43015}
2017-02-07 20:46:47 +00:00
Michael Hablich
0e129692bd Revert "Revert "[parser/test] Simplify test-preparser/PreParserScopeAnalysis.""
This reverts commit 8ee52241e2.

Reason for revert: False alarm, bot hiccup

Original change's description:
> Revert "[parser/test] Simplify test-preparser/PreParserScopeAnalysis."
> 
> This reverts commit 4d8bde0cd6.
> 
> Reason for revert: needed for this revert: https://codereview.chromium.org/2679263002/
> 
> Original change's description:
> > [parser/test] Simplify test-preparser/PreParserScopeAnalysis.
> > 
> > BUG=v8:5516
> > R=​neis@chromium.org
> > 
> > Change-Id: Iabc8d942ffb8107c5284cc51654792a9e2872d0a
> > Reviewed-on: https://chromium-review.googlesource.com/439325
> > Commit-Queue: Marja Hölttä <marja@chromium.org>
> > Reviewed-by: Georg Neis <neis@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#43001}
> 
> TBR=marja@chromium.org,neis@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:5516
> 
> Change-Id: Ia205be1f43fc447119ccc00b16078a968c7b18d1
> Reviewed-on: https://chromium-review.googlesource.com/439147
> Commit-Queue: Michael Hablich <hablich@chromium.org>
> Reviewed-by: Michael Hablich <hablich@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#43009}

TBR=marja@chromium.org,neis@chromium.org,hablich@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5516

Change-Id: Ie8f9ba2925b6b05a2945a9ce435c4c41205feddd
Reviewed-on: https://chromium-review.googlesource.com/439444
Commit-Queue: Michael Hablich <hablich@chromium.org>
Reviewed-by: Michael Hablich <hablich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43014}
2017-02-07 20:44:14 +00:00
hablich
5f9c89af70 Reland of [parsing] Fix maybe-assigned for loop variables. (patchset #1 id:1 of https://codereview.chromium.org/2679263002/ )
Reason for revert:
False alarm, bot hiccup

Original issue's description:
> Revert of [parsing] Fix maybe-assigned for loop variables. (patchset #3 id:40001 of https://codereview.chromium.org/2673403003/ )
>
> Reason for revert:
> Speculative revert because of https://codereview.chromium.org/2679163002/.
>
> Original issue's description:
> > [parsing] Fix maybe-assigned for loop variables.
> >
> > Due to hoisting, the value of a 'var'-declared variable may actually change even
> > if the code contains only the "initial" assignment, namely when that assignment
> > occurs inside a loop.  For example:
> >
> >   let i = 10;
> >   do { var x = i } while (i--):
> >
> > As a simple and very conservative approximation of this, we explicitly mark
> > as maybe-assigned any non-lexical variable whose "declaration" does not
> > syntactically occur in the function scope.  (In the example above, it
> > occurs in a block scope.)
> >
> > BUG=v8:5636
> >
> > Review-Url: https://codereview.chromium.org/2673403003
> > Cr-Commit-Position: refs/heads/master@{#42989}
> > Committed: a33fcd663b
>
> TBR=marja@chromium.org,adamk@chromium.org,neis@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:5636
>
> Review-Url: https://codereview.chromium.org/2679263002
> Cr-Commit-Position: refs/heads/master@{#43010}
> Committed: f3ae5ccf57

TBR=marja@chromium.org,adamk@chromium.org,neis@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5636

Review-Url: https://codereview.chromium.org/2686663002
Cr-Commit-Position: refs/heads/master@{#43013}
2017-02-07 20:43:17 +00:00
hablich
f3ae5ccf57 Revert of [parsing] Fix maybe-assigned for loop variables. (patchset #3 id:40001 of https://codereview.chromium.org/2673403003/ )
Reason for revert:
Speculative revert because of https://codereview.chromium.org/2679163002/.

Original issue's description:
> [parsing] Fix maybe-assigned for loop variables.
>
> Due to hoisting, the value of a 'var'-declared variable may actually change even
> if the code contains only the "initial" assignment, namely when that assignment
> occurs inside a loop.  For example:
>
>   let i = 10;
>   do { var x = i } while (i--):
>
> As a simple and very conservative approximation of this, we explicitly mark
> as maybe-assigned any non-lexical variable whose "declaration" does not
> syntactically occur in the function scope.  (In the example above, it
> occurs in a block scope.)
>
> BUG=v8:5636
>
> Review-Url: https://codereview.chromium.org/2673403003
> Cr-Commit-Position: refs/heads/master@{#42989}
> Committed: a33fcd663b

TBR=marja@chromium.org,adamk@chromium.org,neis@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5636

Review-Url: https://codereview.chromium.org/2679263002
Cr-Commit-Position: refs/heads/master@{#43010}
2017-02-07 19:40:24 +00:00
Michael Hablich
8ee52241e2 Revert "[parser/test] Simplify test-preparser/PreParserScopeAnalysis."
This reverts commit 4d8bde0cd6.

Reason for revert: needed for this revert: https://codereview.chromium.org/2679263002/

Original change's description:
> [parser/test] Simplify test-preparser/PreParserScopeAnalysis.
> 
> BUG=v8:5516
> R=​neis@chromium.org
> 
> Change-Id: Iabc8d942ffb8107c5284cc51654792a9e2872d0a
> Reviewed-on: https://chromium-review.googlesource.com/439325
> Commit-Queue: Marja Hölttä <marja@chromium.org>
> Reviewed-by: Georg Neis <neis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#43001}

TBR=marja@chromium.org,neis@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5516

Change-Id: Ia205be1f43fc447119ccc00b16078a968c7b18d1
Reviewed-on: https://chromium-review.googlesource.com/439147
Commit-Queue: Michael Hablich <hablich@chromium.org>
Reviewed-by: Michael Hablich <hablich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43009}
2017-02-07 19:38:56 +00:00
hablich
9fe08ec067 Revert of Reland: [Parse] ParseInfo owns the parsing Zone. (patchset #7 id:140001 of https://codereview.chromium.org/2632123006/ )
Reason for revert:
Speculative revert because of revert needed for https://codereview.chromium.org/2632123006

Original issue's description:
> Reland: [Parse] ParseInfo owns the parsing Zone.
>
> Moves ownership of the parsing Zone to ParseInfo with a shared_ptr. This is
> in preperation for enabling background compilation jobs for inner functions
> share the AST in the outer-function's parse zone memory (read-only), with the
> and zone being released when all compilation jobs have completed.
>
> BUG=v8:5203,v8:5215
>
> Review-Url: https://codereview.chromium.org/2632123006
> Cr-Original-Commit-Position: refs/heads/master@{#42993}
> Committed: 14fb337200
> Review-Url: https://codereview.chromium.org/2632123006
> Cr-Commit-Position: refs/heads/master@{#42996}
> Committed: 9e7d5a6065

TBR=marja@chromium.org,mstarzinger@chromium.org,ahaas@chromium.org,verwaest@chromium.org,rmcilroy@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5203,v8:5215

Review-Url: https://codereview.chromium.org/2683733002
Cr-Commit-Position: refs/heads/master@{#43008}
2017-02-07 19:35:56 +00:00
Marja Hölttä
4d8bde0cd6 [parser/test] Simplify test-preparser/PreParserScopeAnalysis.
BUG=v8:5516
R=neis@chromium.org

Change-Id: Iabc8d942ffb8107c5284cc51654792a9e2872d0a
Reviewed-on: https://chromium-review.googlesource.com/439325
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43001}
2017-02-07 15:37:46 +00:00
ishell@chromium.org
32971301ea Rename TypeFeedbackVector to FeedbackVector.
... and TypeFeedbackMetadata to FeedbackMetadata.

BUG=

Change-Id: I2556d1c2a8f37b8cf3d532cc98d973b6dc7e9e6c
Reviewed-on: https://chromium-review.googlesource.com/439244
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#42999}
2017-02-07 14:46:36 +00:00
rmcilroy
9e7d5a6065 Reland: [Parse] ParseInfo owns the parsing Zone.
Moves ownership of the parsing Zone to ParseInfo with a shared_ptr. This is
in preperation for enabling background compilation jobs for inner functions
share the AST in the outer-function's parse zone memory (read-only), with the
and zone being released when all compilation jobs have completed.

BUG=v8:5203,v8:5215

Review-Url: https://codereview.chromium.org/2632123006
Cr-Original-Commit-Position: refs/heads/master@{#42993}
Committed: 14fb337200
Review-Url: https://codereview.chromium.org/2632123006
Cr-Commit-Position: refs/heads/master@{#42996}
2017-02-07 14:04:43 +00:00
jochen
8f4c4233dc Revert of Reland: [Parse] ParseInfo owns the parsing Zone. (patchset #6 id:120001 of https://codereview.chromium.org/2632123006/ )
Reason for revert:
doesn't compile on ToT

Original issue's description:
> Reland: [Parse] ParseInfo owns the parsing Zone.
>
> Moves ownership of the parsing Zone to ParseInfo with a shared_ptr. This is
> in preperation for enabling background compilation jobs for inner functions
> share the AST in the outer-function's parse zone memory (read-only), with the
> and zone being released when all compilation jobs have completed.
>
> BUG=v8:5203,v8:5215
>
> Review-Url: https://codereview.chromium.org/2632123006
> Cr-Commit-Position: refs/heads/master@{#42993}
> Committed: 14fb337200

TBR=marja@chromium.org,mstarzinger@chromium.org,ahaas@chromium.org,verwaest@chromium.org,rmcilroy@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5203,v8:5215

Review-Url: https://codereview.chromium.org/2685543003
Cr-Commit-Position: refs/heads/master@{#42994}
2017-02-07 13:02:48 +00:00
rmcilroy
14fb337200 Reland: [Parse] ParseInfo owns the parsing Zone.
Moves ownership of the parsing Zone to ParseInfo with a shared_ptr. This is
in preperation for enabling background compilation jobs for inner functions
share the AST in the outer-function's parse zone memory (read-only), with the
and zone being released when all compilation jobs have completed.

BUG=v8:5203,v8:5215

Review-Url: https://codereview.chromium.org/2632123006
Cr-Commit-Position: refs/heads/master@{#42993}
2017-02-07 12:34:53 +00:00
neis
a33fcd663b [parsing] Fix maybe-assigned for loop variables.
Due to hoisting, the value of a 'var'-declared variable may actually change even
if the code contains only the "initial" assignment, namely when that assignment
occurs inside a loop.  For example:

  let i = 10;
  do { var x = i } while (i--):

As a simple and very conservative approximation of this, we explicitly mark
as maybe-assigned any non-lexical variable whose "declaration" does not
syntactically occur in the function scope.  (In the example above, it
occurs in a block scope.)

BUG=v8:5636

Review-Url: https://codereview.chromium.org/2673403003
Cr-Commit-Position: refs/heads/master@{#42989}
2017-02-07 11:45:09 +00:00
marja
009e8b11e2 [parser/test] Move cctest/PreParserScopeAnalysis into a new file.
BUG=v8:5516
R=vogelheim@chromium.org

Review-Url: https://codereview.chromium.org/2683573002
Cr-Commit-Position: refs/heads/master@{#42986}
2017-02-07 10:11:01 +00:00
vogelheim
10bb974ec3 [scanner] Regression test for Utf-8 BOM handling (crbug.com/685618).
The existing unit test explicitly checked for this case, but was - under
the right circumstances - defeated by the optimization to not re-run the
whole position search if we were close enough.

BUG=chromium:685618

Review-Url: https://codereview.chromium.org/2663883002
Cr-Commit-Position: refs/heads/master@{#42794}
2017-01-30 23:21:03 +00:00
marja
9c7b87269c include fixing: api.h shouldn't include objects-inl.h
Downside: this adds all kinds of weird includes in the .cc files.

(See design doc linked in the bug.)

BUG=v8:5402

Review-Url: https://codereview.chromium.org/2622503002
Cr-Commit-Position: refs/heads/master@{#42140}
2017-01-09 13:43:28 +00:00
jochen
4f2cb8fe82 Reland of "Store SharedFunctionInfos of a Script in a FixedArray indexed by their ID"
Original CL description:
> Store SharedFunctionInfos of a Script in a FixedArray indexed by their ID
>
> Now that SharedFunctionInfos have a unique ID (and the IDs are dense),
> we can use them as an index into an array, instead of using a
> WeakFixedArray where we have to do a linear scan.
>
> Hooking up liveedit is a bit more involved, see
> https://docs.google.com/presentation/d/1FtNa3U7WsF5bPhY9uGoJG5Y9hnz5VBDabfOWpb4unWI/edit
> for an overview
>
> BUG=v8:5589
> R=verwaest@chromium.org,jgruber@chromium.org
>
> Review-Url: https://codereview.chromium.org/2547483002

BUG=v8:5589
TBR=verwaest@chromium.org,jgruber@chromium.org

Review-Url: https://codereview.chromium.org/2577063002
Cr-Commit-Position: refs/heads/master@{#41734}
2016-12-15 17:19:55 +00:00
kozyatinskiy
3dea2c8354 Revert of Store SharedFunctionInfos of a Script in a FixedArray indexed by their ID (patchset #11 id:190001 of https://codereview.chromium.org/2547483002/ )
Reason for revert:
LiveEdit is broken in some cases.

Original issue's description:
> Store SharedFunctionInfos of a Script in a FixedArray indexed by their ID
>
> Now that SharedFunctionInfos have a unique ID (and the IDs are dense),
> we can use them as an index into an array, instead of using a
> WeakFixedArray where we have to do a linear scan.
>
> Hooking up liveedit is a bit more involved, see
> https://docs.google.com/presentation/d/1FtNa3U7WsF5bPhY9uGoJG5Y9hnz5VBDabfOWpb4unWI/edit
> for an overview
>
> BUG=v8:5589
> R=verwaest@chromium.org,jgruber@chromium.org
>
> Committed: https://crrev.com/6595e7405769dc9d49e9568d61485efc6d468baf
> Cr-Commit-Position: refs/heads/master@{#41600}

TBR=jgruber@chromium.org,verwaest@chromium.org,yangguo@chromium.org,jochen@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=v8:5589,chromium:673950
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2578433002
Cr-Commit-Position: refs/heads/master@{#41684}
2016-12-14 02:05:05 +00:00
jochen
6595e74057 Store SharedFunctionInfos of a Script in a FixedArray indexed by their ID
Now that SharedFunctionInfos have a unique ID (and the IDs are dense),
we can use them as an index into an array, instead of using a
WeakFixedArray where we have to do a linear scan.

Hooking up liveedit is a bit more involved, see
https://docs.google.com/presentation/d/1FtNa3U7WsF5bPhY9uGoJG5Y9hnz5VBDabfOWpb4unWI/edit
for an overview

BUG=v8:5589
R=verwaest@chromium.org,jgruber@chromium.org

Review-Url: https://codereview.chromium.org/2547483002
Cr-Commit-Position: refs/heads/master@{#41600}
2016-12-08 17:07:11 +00:00
verwaest
ce63eb08f9 [counters] Move waiting for more data from background-parsing into callbacks
BUG=

Review-Url: https://codereview.chromium.org/2549083002
Cr-Commit-Position: refs/heads/master@{#41492}
2016-12-05 15:47:12 +00:00
vogelheim
9d0f5ab745 Treat all functions in a 'comma sequence' the same for (pre-)parsing.
R=verwaest@chromium.org
BUG=v8:5643

Review-Url: https://codereview.chromium.org/2524263003
Cr-Commit-Position: refs/heads/master@{#41267}
2016-11-24 14:45:19 +00:00
vogelheim
56daccb836 Fix memory leak in cctest/parsing/test-scanner.
BUG=chromium:662388

Review-Url: https://codereview.chromium.org/2495533003
Cr-Commit-Position: refs/heads/master@{#41266}
2016-11-24 14:29:09 +00:00
vogelheim
eefe11a1e6 Treat a '!' preceding a function literal as eager-compile hint.
Some minifiers use the pattern !function ... () for JS code that should
be immediately executed. This change recognizes that pattern and treats
it equally to parenthesized functions.

A bit more background info is in the referenced bug.

R=verwaest@chromium.org
BUG=v8:5643

Review-Url: https://codereview.chromium.org/2509143003
Cr-Commit-Position: refs/heads/master@{#41114}
2016-11-18 14:56:59 +00:00
vogelheim
3019b49764 Fix memory leak in test-scanner.cc.
BUG=chromium:662388

Review-Url: https://codereview.chromium.org/2468423008
Cr-Commit-Position: refs/heads/master@{#40781}
2016-11-04 18:54:14 +00:00
predrag.rudic
f04a9b4936 Fix 'MIPS: Fix Utf16CharacterStream scanner crash due to missaligned access'
Removed a wrong condition test in  TwoByteExternalBufferedStream. This changed fixes errors that may occur under some conditions.

Review-Url: https://codereview.chromium.org/2469723002
Cr-Commit-Position: refs/heads/master@{#40722}
2016-11-03 12:32:16 +00:00
vogelheim
138127a608 Fix bad-char handling in utf-8 streaming streams. Also add test.
R=jochen@chromium.org
BUG=chromium:651333, v8:4947

Review-Url: https://codereview.chromium.org/2391273002
Cr-Commit-Position: refs/heads/master@{#40004}
2016-10-05 17:18:58 +00:00
vogelheim
295bafd4bc [parser] Use Back2() where appropriate.
R=marja@chromium.org
BUG=v8:4947

Review-Url: https://codereview.chromium.org/2366573002
Cr-Commit-Position: refs/heads/master@{#39662}
2016-09-23 13:16:19 +00:00
vogelheim
a2b8b6e7db Handle Utf-8 BOM at beginning of an Utf-8 stream.
(This should enable to drop the BOM handling in the Blink bindings.)

R=marja@chromium.org
BUG=v8:4947

Review-Url: https://codereview.chromium.org/2354973002
Cr-Commit-Position: refs/heads/master@{#39579}
2016-09-21 08:40:10 +00:00
ivica.bogosavljevic
ade29503dd Fix compilation failure with GCC 5
BUG=

Review-Url: https://codereview.chromium.org/2353943002
Cr-Commit-Position: refs/heads/master@{#39576}
2016-09-21 07:18:46 +00:00
vogelheim
05a00a93b1 Simplify Scanner bookmarking.
- Eliminates *all* copies in the process.
- Moves (nearly) all functionality into Scanner::BookmarkScope.
- Significant code reduction.

[Needs to be rebased once crrev.com/2347883002 lands. All changes in *parser* are from that CL.]

R=marja@chromium.org
BUG=v8:4947

Review-Url: https://codereview.chromium.org/2341323002
Cr-Commit-Position: refs/heads/master@{#39554}
2016-09-20 13:48:04 +00:00
vogelheim
b36c60cce8 Remove legacy API on Utf16CharacterStream.
BUG=v8:4947

Review-Url: https://codereview.chromium.org/2347883002
Cr-Commit-Position: refs/heads/master@{#39533}
2016-09-20 09:44:00 +00:00
vogelheim
d8eeaed3f9 Behold, a unit test for Scanner::BookmarkScope (& scanner bookmarking).
This is in preparation for upcmoming scanner + bookmarking cleanups.

Also, drive-by fix for setting a bookmark close to the end of the stream,
when the look-ahead character (c0_) is kEndOfInput, which the bookmarking
logic also used as kNoBookmark.

R=marja@chomium.org
BUG=v8:4947

Review-Url: https://codereview.chromium.org/2345053003
Cr-Commit-Position: refs/heads/master@{#39507}
2016-09-19 16:51:05 +00:00
vogelheim
642d6d314c Rework scanner-character-streams.
- Smaller, more consistent streams API (Advance, Back, pos, Seek)
- Remove implementations from the header, in favor of creation functions.

Observe:
- Performance:
  - All Utf16CharacterStream methods have an inlinable V8_LIKELY w/ a
    body of only a few instructions. I expect most calls to end up there.
  - There used to be performance problems w/ bookmarking, particularly
    with copying too much data on SetBookmark w/ UTF-8 streaming streams.
    All those copies are gone.
  - The old streaming streams implementation used to copy data even for
    2-byte input. It no longer does.
  - The only remaining 'slow' method is the Seek(.) slow case for utf-8
    streaming streams. I don't expect this to be called a lot; and even if,
    I expect it to be offset by the gains in the (vastly more frequent)
    calls to the other methods or the 'fast path'.
  - If it still bothers us, there are several ways to speed it up.
- API & code cleanliness:
  - I want to remove the 'old' API in a follow-up CL, which should mostly
    delete code, or replace it 1:1.
  - In a 2nd follow-up I want to delete much of the UTF-8 handling in Blink
    for streaming streams.
  - The "bookmark" is now always implemented (and mostly very fast), so we
    should be able to use it for more things.
- Testing & correctness:
  - The unit tests now cover all stream implementations,
    and are pretty good and triggering all the edge cases.
  - Vastly more DCHECKs of the invariants.

BUG=v8:4947

Review-Url: https://codereview.chromium.org/2314663002
Cr-Commit-Position: refs/heads/master@{#39464}
2016-09-16 08:29:52 +00:00