Commit Graph

422 Commits

Author SHA1 Message Date
Alexander Aprelev 99e8f560af Revert "Revert "Reintroduce incremental compiler wrapper that supports accept protocol.""
This reverts commit 2d4c606e63.

The fix for the debug buildbot breakage now consists of skipping wide to utf8 conversion
altogether, instead move uri to path conversion directly into newly added File::OpenUri method.

Change-Id: Id3d7457d6a6b5045e5f38678548f4d7bed6d2c43
Reviewed-on: https://dart-review.googlesource.com/39801
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Zach Anderson <zra@google.com>
2018-02-07 20:58:51 +00:00
Alexander Aprelev 2d4c606e63 Revert "Reintroduce incremental compiler wrapper that supports accept protocol."
This reverts commit d78a41e0ee.

Revert "Fix length for WideToUTF8 conversion in UriToPath"

This reverts commit 011e1cc1c5.

Change-Id: I36140426a474962f77605e1aed6ddfd158bd064a
Reviewed-on: https://dart-review.googlesource.com/39480
Reviewed-by: Alexander Aprelev <aam@google.com>
2018-02-07 04:02:36 +00:00
Alexander Aprelev d78a41e0ee Reintroduce incremental compiler wrapper that supports accept protocol.
This reverts 4e677e9606

Change-Id: I32410b3a4ee9cc8a6f3318917ed519e13eea14f6
Reviewed-on: https://dart-review.googlesource.com/37862
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
2018-02-06 18:38:58 +00:00
Martin Kustermann 0a652c9ca9 Revert "[VM] Use IR for code in [CatchEntryInstr]s to populate captured exception/stacktrace variables"
This reverts commit 12759870a4.

Reason for revert: Broke many bots.

Original change's description:
> [VM] Use IR for code in [CatchEntryInstr]s to populate captured exception/stacktrace variables
> 
> This fixes an issue when a program got loaded via dill, a function
> with a try-catch got optimized and the exception/stacktrace variables
> got captured.
> 
> Change-Id: Ia6b62f2a0986c78b90afe7fae25025ca4e5b09db
> Reviewed-on: https://dart-review.googlesource.com/35182
> Commit-Queue: Martin Kustermann <kustermann@google.com>
> Reviewed-by: Vyacheslav Egorov <vegorov@google.com>

TBR=vegorov@google.com,kustermann@google.com

Change-Id: I2ec7b4bea401e6d5665f6e789eb8e241b99db7b3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/36200
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
2018-01-21 20:46:49 +00:00
Martin Kustermann 12759870a4 [VM] Use IR for code in [CatchEntryInstr]s to populate captured exception/stacktrace variables
This fixes an issue when a program got loaded via dill, a function
with a try-catch got optimized and the exception/stacktrace variables
got captured.

Change-Id: Ia6b62f2a0986c78b90afe7fae25025ca4e5b09db
Reviewed-on: https://dart-review.googlesource.com/35182
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2018-01-21 16:12:58 +00:00
Martin Kustermann cf1de7d46c [VM] Replace hand-written assembly prologues with IR
As part of the prologue changes we get rid of the empty context as well.

Issue https://github.com/dart-lang/sdk/issues/31495

Change-Id: I707e23c631bcfbbad6c91c4963d0c10f7a0be625
Reviewed-on: https://dart-review.googlesource.com/25320
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2017-12-13 16:04:34 +00:00
Siva Chandra 702e4aecb8 Keep the line starts delta encoded in the VM heap as well - take 2
This reverts commit adf04d0ac6.

The original change used macros from stdint.h and it failed build on
the linux sdk bot:
https://uberchromegw.corp.google.com/i/client.dart/builders/dart-sdk-linux-be/builds/17348

In the newer version, constants from runtime/platform/globals.h are used
instead of the macros from stdint.h. Constants for int8 have been added as
they were not present already.

Change-Id: Ia4f27613fa5dca2cd6dbfeb37715ea70a85cec95
Reviewed-on: https://dart-review.googlesource.com/25083
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Siva Chandra <sivachandra@google.com>
2017-12-01 05:16:48 +00:00
Samir Jindel be07555207 Revert "Revert "[kernel] Implementation of fine-grained strong mode argument type-checks, phase 2""
This fixes some incorrect asserts that were breaking the debug bots.
The original revision is available in Patchset 1.

This reverts commit 26735519cb.

Bug:
Change-Id: Ifa599b7bff752dec4c505e10fd6db206e1abd977
Reviewed-on: https://dart-review.googlesource.com/23820
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Samir Jindel <sjindel@google.com>
2017-11-27 18:25:31 +00:00
Vyacheslav Egorov 26735519cb Revert "[kernel] Implementation of fine-grained strong mode argument type-checks, phase 2"
This reverts commit f13f772bb2.

Reason for revert: dartk(p)-strong debug mode is completely broken
because we convert int values non-representable as Smi to Smi, which
triggers that assert. The code that does tagging checks that
Untag(Tag(x)) == x, however for our purposes this identity does not
need to hold because we only care about lower bits and ignore the sign.

Reverting to restore green-ness of DEBUG builds.

TBR=sjindel@google.com

Bug:
Change-Id: Id436cbe000d6dec8db3469070ed531327cc82d89
Reviewed-on: https://dart-review.googlesource.com/23661
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2017-11-26 10:21:01 +00:00
Samir Jindel f13f772bb2 [kernel] Implementation of fine-grained strong mode argument type-checks, phase 2
This revision continues the implementation of:
https://docs.google.com/document/d/1KK8b6kzr0pQev5YNftSZhN3M6I8HcvOJwJ6U-cW4nfw/edit?ts=5a05b3e9#heading=h.7j21arix8p2

* Add argument checking bits for named arguments in the arguments descriptor.
* Add argument checking bits for type arguments.
* Calculate argument checking bits for setters.
* Add dispatch category to PropertySet and DirectPropertySet.

Bug:
Change-Id: Ieb0a4a99c401f53a72de473fda7bab61581f9996
Reviewed-on: https://dart-review.googlesource.com/22700
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
2017-11-24 18:23:57 +00:00
Erik Corry d300b08e35 [VM] Use X64 disassembler for IA32 and X64 (reland)
R=vegorov@google.com

This removes the IA32 disassembler and uses the X64 disassembler for
both variants.  Instructions that were in the IA32 assembler, but not
supported by the X64 disassembler have been added.  It also adds some
regression tests for a lot of the disassembler output.
Bug:
Change-Id: I243abbb04c3a77810ce96ca74f7f42a5a1aea0cf
Reviewed-on: https://dart-review.googlesource.com/22982
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Erik Corry <erikcorry@google.com>
2017-11-22 12:04:18 +00:00
Erik Corry 80992a5a09 Revert "[VM] Use X64 disassembler for IA32 and X64"
This reverts commit 9e42f006d9.
due to test failures on non-Linux platforms.

R=karlklose@google.com

Bug:
Change-Id: I5dc40da75d8d89fca8fce98a69a39d767493af1b
Reviewed-on: https://dart-review.googlesource.com/22921
Reviewed-by: Karl Klose <karlklose@google.com>
2017-11-22 09:11:12 +00:00
Erik Corry 9e42f006d9 [VM] Use X64 disassembler for IA32 and X64
R=vegorov@google.com

Bug:
Change-Id: I19b1f58e16ea35dc81b941c54e6e57b97cad3d74
Reviewed-on: https://dart-review.googlesource.com/22020
Commit-Queue: Erik Corry <erikcorry@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2017-11-22 08:01:07 +00:00
Samir Jindel a991c17dc9 [kernel] Implementation of fine-grained strong mode argument type-checks, phase 1
The revision begins the implementation of:
https://docs.google.com/document/d/1KK8b6kzr0pQev5YNftSZhN3M6I8HcvOJwJ6U-cW4nfw/edit?ts=5a05b3e9#heading=h.7j21arix8p2

* The ArgumentsDescriptor is updated to hold a bitvector for positional arguments.
* The kernel flowgraph builder is updated to calculate the appropriate bits from
  the interface target and pass them through the ArgumentsDescriptor
  for regular MethodInvocations.

Bug:
Change-Id: I1cd9f43f697df1dd4f36103bbdfc0ba000125c02
Reviewed-on: https://dart-review.googlesource.com/21541
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
2017-11-21 15:35:48 +00:00
Erik Corry 1109ffcb6a [VM] Add ARM64 bitfield instructions
R=rmacnak@google.com

Also some minor cleanup in the way we encode ARM instructions.
I'll be needing these for 32 bit Smis on ARM64.
Bug:
Change-Id: I5f515590375a2c6ad11bc6f1a80a4f8e27cd82b4
Reviewed-on: https://dart-review.googlesource.com/20668
Commit-Queue: Erik Corry <erikcorry@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2017-11-16 15:34:11 +00:00
Ryan Macnak 374c21ccb4 [vm] Improve packing of StackMaps.
Flutter gallery ARM32:
StackMaps        1248008 ->   898886 (-28.0%)
Total snapshot  11089876 -> 10741228 (-3.1%)

Bug: https://github.com/dart-lang/sdk/issues/31302
Change-Id: I61c6fbf9024648907238d1d835d13d75b17f224a
Reviewed-on: https://dart-review.googlesource.com/20480
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2017-11-14 20:04:14 +00:00
Ryan Macnak f60efb7e40 Reapply "[vm] Popcount via compiler intrinsics."
Add missing rename of CountOneBits in ARM assembler.

Change-Id: I735da06343248573a1b049109ebc2bf0d1634960
Reviewed-on: https://dart-review.googlesource.com/18504
Reviewed-by: Zach Anderson <zra@google.com>
2017-11-03 17:39:16 +00:00
Ryan Macnak 2761c556ca Revert "[vm] Popcount via compiler intrinsics."
This reverts commit c4f4cdbf29.

Reason for revert: ARM compile-time errors

Original change's description:
> [vm] Popcount via compiler intrinsics.
> 
> Change-Id: I8913beea7b984f04cec7f9efc00673aa12095eda
> Reviewed-on: https://dart-review.googlesource.com/18423
> Reviewed-by: Zach Anderson <zra@google.com>

TBR=rmacnak@google.com,zra@google.com

Change-Id: I5efe8100e3c1fa404b1c24f369dca5c137acd2b8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/18640
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2017-11-03 16:50:47 +00:00
Ryan Macnak c4f4cdbf29 [vm] Popcount via compiler intrinsics.
Change-Id: I8913beea7b984f04cec7f9efc00673aa12095eda
Reviewed-on: https://dart-review.googlesource.com/18423
Reviewed-by: Zach Anderson <zra@google.com>
2017-11-03 16:34:35 +00:00
Zachary Anderson 9ab8b55663 [gn] Split target arch/os defines from dart_config
This is a baby-step towards building an SDK targeting the host arch
during a cross-build. This will require a similar update to the use
of dart_config in the Flutter engine at //flutter/lib/io/BUILD.gn:19.

Change-Id: I8b871cceb53038cab8407264664c5ce545e6e010
Reviewed-on: https://dart-review.googlesource.com/17523
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2017-10-31 17:33:13 +00:00
Ryan Macnak 031069d2bd [vm] Avoid using a generated stub to get the current SP, since generated stubs aren't available during early start up.
Change-Id: Ib0d78965ba5ccb1fa2b084d82b2bb79485b7900f
Reviewed-on: https://dart-review.googlesource.com/12780
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Zach Anderson <zra@google.com>
2017-10-10 22:52:25 +00:00
Ryan Macnak 3609522166 printf format checking is a compiler feature, not a platform feature.
Change-Id: Ib3e0beb814b5cae6f2b4be13f055069f682674f5
Reviewed-on: https://dart-review.googlesource.com/11645
Reviewed-by: Zach Anderson <zra@google.com>
2017-10-09 22:26:01 +00:00
Alexander Markov f6d6766920 [VM] Restore disassembler in flutter/profile (dart/release) mode
This CL restores disassembler in precompiled mode after it was removed
in 8cb752f73b.
Without disassembler observatory is not able to show assembly code
in 'flutter run --profile' mode.

This CL also pulls BufferFormatter out of il_printer.h/.cc as it is also
used in disassembler.

Change-Id: I098ddb8d8f5a2426028c1f467d58e5c2d6a82d21
Reviewed-on: https://dart-review.googlesource.com/7486
Reviewed-by: Zach Anderson <zra@google.com>
2017-09-21 16:07:02 +00:00
Ryan Macnak 3d21a46b72 Limit preserialized JSON for timeline events from Dart code to the arguments.
Avoids string copies in C++ and map copies in Dart.

Also remove some vestiages of removed feature that allowed an embedder to add pre-encoded events to the timeline.

Change-Id: I962a67093ba461c991d9169b0391c44af1d489db
Bug: https://github.com/dart-lang/sdk/issues/30787
Reviewed-on: https://dart-review.googlesource.com/6762
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Zach Anderson <zra@google.com>
2017-09-19 23:29:55 +00:00
Alexander Markov ffc85d1e92 [VM] Fix undefined behavior in Utils::Abs
Issue: https://github.com/dart-lang/sdk/issues/30572

Change-Id: If8c743edb140edb7a7f803521b51c776d41db5d6
Reviewed-on: https://dart-review.googlesource.com/5881
Reviewed-by: Zach Anderson <zra@google.com>
2017-09-14 18:15:17 +00:00
Zachary Anderson 3470145529 [Fuchsia] Update to use new tracing API
Change-Id: Ied0bc594fe16f427be10444ad5739a30b7003acc
Reviewed-on: https://dart-review.googlesource.com/4062
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2017-09-12 16:42:07 +00:00
Zachary Anderson 734beef062 [infra] Translate _sources.gypi files to _sources.gni files
Also deletes code that becomes dead as a result.

R=rmacnak@google.com

Review-Url: https://codereview.chromium.org/2996903002 .
2017-08-14 21:54:36 -07:00
Alexander Markov ed74405635 [vm] Revise Dart_IntegerToHexCString to avoid dependency on Bigint, v.2
Reapply 3d4838fc70 with the following
modifications:
* define PRIX64 to fix compilation errors on Windows;
* add and use short form format specifiers PX and PX64 to make it
  uniform with other format specifiers.

Original review: https://codereview.chromium.org/2987183002

Description of the original CL:

Until this change, implementation of Dart_IntegerToHexCString()
always created Bigint objects and used Bigint::ToHexCString() to do
the work.

In --limit-ints-to-64-bits mode (with Dart integers limited to 64
bits) Bigints are banned and should not be used.
This CL revises Dart_IntegerToHexCString implementation to avoid
creating Bigint objects for Smi and Mint arguments, so it would
work in --limit-ints-to-64-bits mode.

Also, this CL adds test case to lock down the behavior of
Dart_IntegerToHexCString.

R=zra@google.com

Issue: https://github.com/dart-lang/sdk/issues/30103
Review-Url: https://codereview.chromium.org/2985423002 .
2017-08-01 10:49:51 -07:00
Zachary Anderson 6cd8a79078 VM: Re-format to use at most one newline between functions
R=asiva@google.com

Review-Url: https://codereview.chromium.org/2974233002 .
2017-07-13 08:08:37 -07:00
Alexander Markov 7a20b6b8d8 Option to truncate integers to 64 bits, part 1 (core VM changes)
This changeset revises --limit-ints-to-64-bits option to
change range of integers from unlimited to int64.
On overflow, integer arithmetic operations silently wrap around and
discard extra bits. No Bigints are allocated in case of overflow.

This changeset is the 1st part in the series of changes, it revises the implementation of integer arithmetic operations. More changes will follow.

R=regis@google.com, zra@google.com

Issue: https://github.com/dart-lang/sdk/issues/30103
Review-Url: https://codereview.chromium.org/2974633003 .
2017-07-10 15:16:40 -07:00
Erik Corry 029b1cb948 Spelling fixes e to i.
R=kevmoo@google.com
BUG=

Review-Url: https://codereview.chromium.org/2957593002 .
2017-06-24 13:41:39 +02:00
Zachary Anderson ac16656161 Remove MIPS support
R=asiva@google.com

Review-Url: https://codereview.chromium.org/2858623002 .
2017-06-22 08:49:22 -07:00
Ryan Macnak e1b31c6b4b [arm, arm64] Convince the Android toolchain not to bypass memcpy in Read/StoreUnaligned.
R=zra@google.com

Review-Url: https://codereview.chromium.org/2953653002 .
2017-06-21 14:03:50 -07:00
Ryan Macnak dddd96cfd2 [arm] Avoid unaligned access fault in Int32x4/Float32x4::value().
R=zra@google.com

Review-Url: https://codereview.chromium.org/2947783002 .
2017-06-21 09:11:04 -07:00
Zachary Anderson 5850122513 Fix simarm build for newer gcc's
R=rmacnak@google.com

Review-Url: https://codereview.chromium.org/2924473002 .
2017-06-05 09:22:06 -07:00
Erik Corry aa60a2ea90 More compact string representation on 64 bit.
This moves the hash code into the header word for strings on 64 bit
platforms.  With the old layout, 9 character strings became 48-byte
objects.  With the new layout you have to go to 17 characters before
you are bumped from 4 to 6 words (32 to 48 bytes).

As a side effect, the class ID field is now 16 bits on all platforms
instead of having two different sizes, and the size field is 8 bits
on all platforms.

This also paves the way for moving the hash code for instance objects
into the header, so we won't need the side-lookup in the
hash-table-of-hash-codes on 64 bit platforms.

This is a reapplication of https://codereview.chromium.org/2893553002/
after issues were fixed in https://codereview.chromium.org/2888413002/
and https://codereview.chromium.org/2896583002/

R=vegorov@google.com
BUG=

Review-Url: https://codereview.chromium.org/2895183002 .
2017-05-22 10:04:59 +02:00
Dmitry Stefantsov e5f93a068f Revert "More compact string representation on 64 bit."
This reverts commit 5c8e472c82.

TBR=erikcorry@google.com

Review-Url: https://codereview.chromium.org/2889723005 .
2017-05-18 14:23:12 +02:00
Erik Corry 5c8e472c82 More compact string representation on 64 bit.
This moves the hash code into the header word for strings on 64 bit
platforms.  With the old layout, 9 character strings became 48-byte
objects.  With the new layout you have to go to 17 characters before
you are bumped from 4 to 6 words (32 to 48 bytes).

As a side effect, the class ID field is now 16 bits on all platforms
instead of having two different sizes, and the size field is 8 bits
on all platforms.

This also paves the way for moving the hash code for instance objects
into the header, so we won't need the side-lookup in the
hash-table-of-hash-codes on 64 bit platforms.

R=vegorov@google.com
BUG=

Review-Url: https://codereview.chromium.org/2893553002 .
2017-05-18 11:54:40 +02:00
Erik Corry aa6353b6da Dart SDK Spelling b, c, and d.
R=kmillikin@google.com
BUG=

Review-Url: https://codereview.chromium.org/2850783002 .
2017-05-01 08:28:10 +02:00
Zachary Anderson 8c9c54d833 [dart:io] Don't close stdin with a socket finalizer
If an Isolate touches the 'stdio' getter, a _NativeSocket with
attached finalizer is created for it. Previously, when such an
Isolate exited, the finalizer would close the underlying
file descriptor. This CL changes the finalizer for stdin such
that the native objects will be cleaned up, but the underlying
file descriptor will not be closed. The underlying file
descriptor will now only be closed if the stdin stream
subscription is explicitly canceled.

Accessing the stdin getter after the stream is explicitly
canceled will result in a FileSystemException.

See also: https://github.com/dart-lang/test/issues/583

fixes #29229

R=rmacnak@google.com

Review-Url: https://codereview.chromium.org/2791423002 .
2017-04-04 13:57:42 -07:00
Ryan Macnak 9f2668c998 Set TARGET_OS_* from GN, falling back to HOST_OS_*.
Use TARGET_OS_* instead of HOST_OS_* to decide on the assembly variant to use. Allows, say, a gen_snapshot compiled for a Mac to target Android when generating AOT as assembly.

R=fschneider@google.com, zra@google.com

Review-Url: https://codereview.chromium.org/2757783003 .
2017-03-20 14:48:28 -07:00
Ryan Macnak 877284947b Rename TARGET_OS_* to HOST_OS_*.
Like HOST_ARCH_*, HOST_OS_* describes the OS the VM is running on, which may be different from the OS the VM is generating code for during AOT compilation.

Currently we conflate the two when emitting AOT as assembly, and we get away with it because Flutter only uses assembly for targeting iOS and one can only target iOS from a Mac, but we expect to use assembly for Android as well so native tools can unwind Dart frames.

R=zra@google.com

Review-Url: https://codereview.chromium.org/2750843003 .
2017-03-15 13:11:05 -07:00
Ryan Macnak 781fd36086 Add an option to gen_snapshot for creating a Makefile describing a snapshot's dependencies. This option may be used when generating any snapshot kind, or without generating a snapshot.
- Factor out MallocGrowableArray from vm to platform.
 - Add File::Print.

R=asiva@google.com

Review-Url: https://codereview.chromium.org/2715463003 .
2017-02-23 12:40:48 -08:00
Ryan Macnak 9eb216a495 Reapply "Create an app snapshot of the Dart front end."
Skip training on Windows, issue #28532.

R=hausner@google.com

Review-Url: https://codereview.chromium.org/2665753002 .
2017-01-31 09:47:51 -08:00
Ryan Macnak 728f460798 Revert "Create an app snapshot of the Dart front end."
This reverts commit 8c7111c967.
This reverts commit 27c8e59d2e.

Review-Url: https://codereview.chromium.org/2657123002 .
2017-01-26 17:42:25 -08:00
Ryan Macnak 8c7111c967 Create an app snapshot of the Dart front end.
R=asiva@google.com, hausner@google.com, zra@google.com

Review-Url: https://codereview.chromium.org/2655173002 .
2017-01-26 16:28:59 -08:00
Martin Kustermann a9fbe2004d VM: Tell lsan about mmap()ed regions used for our heap
The mmap()ed pages hold pointers to `VirtualMemory` objects. So we tell
lsan that the mmap()ed regions are roots.

R=vegorov@google.com

Review-Url: https://codereview.chromium.org/2646363005 .
2017-01-24 12:47:36 +01:00
Ryan Macnak 4f598c584d GN: Fix cross ARM64 and cross MIPS builds.
R=zra@google.com

Review-Url: https://codereview.chromium.org/2643583002 .
2017-01-20 15:44:24 -08:00
Martin Kustermann 37dfdbdc97 VM: Remove unused (and incomplete) HashMap::Remove() function
R=vegorov@google.com

Review URL: https://codereview.chromium.org/2542103002 .
2016-12-01 13:51:49 +01:00
Martin Kustermann d822f36f15 VM: Fix memory leak during shutdown
The way runtime/platform/hashmap.h:HashMap was implemented so far did not allow
deleting elements while iterating over the map. If one iterated like this

  HashMap::Entry* cursor = map.Start();
  while (cursor != NULL) {
    if (cond) {
      map.Remove(cursor->key, cursor->hash);
    }
    cursor = map.Next(cursor);
  }

Then the iteration `cursor` will skip elements. This is due to the fact that
`HashMap::Remove()` is left-rotating elements in certain cases and
`HashMap::Next()` will unconditionally advance to the next position in the
backing store.

PROBLEM IS: There was existing code which did remove elements while iterating
over a HashMap.

R=fschneider@google.com

Review URL: https://codereview.chromium.org/2533303005 .
2016-11-30 23:52:04 +01:00