Commit Graph

28 Commits

Author SHA1 Message Date
Jakob Kummerow
9302db480e [ubsan] Port HeapObject to the new design
Merging the temporary HeapObjectPtr back into HeapObject.

Bug: v8:3770
Change-Id: I5bcd23ca2f5ba862cf5b52955dca143e531c637b
Reviewed-on: https://chromium-review.googlesource.com/c/1386492
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58410}
2018-12-20 16:43:49 +00:00
Jakob Kummerow
7f21bbc11d [ubsan] Port Foreign and Managed to the new design
Bug: v8:3770
Change-Id: Ie80ce957ff1d2bcd3596491066f6562ce0ad129a
Reviewed-on: https://chromium-review.googlesource.com/c/1380114
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58294}
2018-12-17 20:31:45 +00:00
Igor Sheludko
6663ed49dc [ptr-compr] Remove default implementation of ObjectVisitor::VisitEmbeddedPointer()
which used to treat off-heap slots as on-heap ones and implement embedded objects
visitation in derived visitor classes.

Bug: v8:8518
Change-Id: Ia40d8135078379cca990e9167d3f1bebb3b5be0a
Reviewed-on: https://chromium-review.googlesource.com/c/1367747
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58123}
2018-12-10 12:45:28 +00:00
Igor Sheludko
126b2cc438 [ptr-compr] Remove default implementation of ObjectVisitor::VisitCodeTarget()
which used to treat off-heap slots as on-heap ones and implement code target
visitation in derived visitor classes.

Bug: v8:8518
Change-Id: I477bf3a4a8a3de0c67bc15e2e20d8ecee6493da8
Reviewed-on: https://chromium-review.googlesource.com/c/1367745
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58121}
2018-12-10 11:08:07 +00:00
Igor Sheludko
8799f78080 [ptr-compr] Use FullObjectSlot for off-heap slots
(mostly for roots, handles and stack locations).
Thi CL also changes RootVisitor interface to use FullObjectSlots instead of
ObjectSlots.

Bug: v8:8518
Change-Id: I217c7ae176387a8c64f4754e62339727bdb36018
Reviewed-on: https://chromium-review.googlesource.com/c/1366035
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58091}
2018-12-07 12:35:27 +00:00
Jakob Kummerow
fe61cd6487 [ubsan] Port Code to the new design
Bug: v8:3770
Change-Id: I413ce57f7fa91cef2445995ca22650477f92b0df
Reviewed-on: https://chromium-review.googlesource.com/c/1321892
Reviewed-by: Dan Elphick <delphick@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57445}
2018-11-12 18:47:04 +00:00
Jakob Kummerow
266c0b967b [ubsan,heap] Replace Object** with ObjectSlot
as part of the continuing quest to get rid of Object*/Object**.
This is a fairly mechanical replacement of Object**/MaybeObject** with
wrapper objects carrying the same data. No change in behavior is intended.
Overloaded operators are provided to minimize code churn.

Bug: v8:3770
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I76cee82b8bf2dd80a1b66f09dd2bb2b65038eeb7
Reviewed-on: https://chromium-review.googlesource.com/c/1287889
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56920}
2018-10-24 00:14:20 +00:00
Dan Elphick
f602712f6f [snapshot] Create a ReadOnly snapshot
In preparation for sharing RO_SPACE between all Isolates within a
process, this first pulls RO_SPACE out of the Startup snapshot and puts
it in its own ReadOnly snapshot.

The snapshot is first populated with the read-only roots. After that the
StartupSerializer serializes as before but starting from the first
mutable root. References to objects in the ReadOnly snapshot that aren't
themselves roots are added to a new cache called ReadOnlyObjectCache
which functions like the PartialSnapshotCache but lives in the
ReadOnlySerializer rather than the StartupSerializer. These cache
entries are referenced using a new bytecode: ReadOnlyObjectCache. (To
make room for this, the ApiReference bytecode has been moved).

To reduce code duplication, the StartupSerializer has been refactored to
create a new base class RootSerializer, which ReadOnlySerializer also
subclasses. The base class is responsible primarily for keeping track of
already serialized roots and visiting the roots.

Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: Iff26042886130ae22eccf2e11b35f6f226f4a792
Bug: v8:8191
Reviewed-on: https://chromium-review.googlesource.com/c/1244676
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56681}
2018-10-16 10:13:20 +00:00
Dan Elphick
08b8e0ff5a Clarify roots iteration
Change Heap::IterateStrongRoots to never iterate the read-only roots. In
doing so remove VISIT_ALL_BUT_READ_ONLY and
VISIT_ONLY_STRONG_FOR_SERIALIZATION. All such uses should now use
VISIT_ALL and VISIT_ONLY_STRONG. Where ReadOnlyRoots iteration is
required, this adds ReadOnlyRoots(isolate)->Iterate() at the call site.

Add new begin, end, strong_mutable_roots_begin and
strong_mutable_roots_end methods to RootsTable and try and make the
existing uses a little more consistent.

Bug: v8:8191
Change-Id: Ie9d0f9e5186db418428e2fafd38432b0bd879daa
Reviewed-on: https://chromium-review.googlesource.com/c/1278500
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56672}
2018-10-16 08:42:30 +00:00
Marja Hölttä
737a4e4c19 [in-place weak refs] Cleanup: Remove BodyDescriptorWeak
Unification: now BodyDescriptor deals with all weakness types.

This doesn't replace the weak list pointers with in-place weak references, since
it would cause extra work: we anyway recreate the lists after GC, so we
shouldn't track them at all during GC.

BUG=v8:7308

Change-Id: Ifb2f573d3e7ee311136b59e185cc659487c9cab3
Reviewed-on: https://chromium-review.googlesource.com/1229894
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56030}
2018-09-19 12:57:40 +00:00
Florian Sattler
a072e666f6 [cleanup] Refactor first batch of general classes to use default members.
Fixing clang-tidy warning.

Bug: v8:8015
Change-Id: Ibc5a81aea25f797e90db891e90b2977f27e13990
Reviewed-on: https://chromium-review.googlesource.com/1224410
Commit-Queue: Florian Sattler <sattlerf@google.com>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56015}
2018-09-19 08:32:08 +00:00
Clemens Hammacher
a2139261ca [cleanup] Remove empty and deprecated BASE_EMBEDDED macro
The macro has been deprecated since 2016, and it keeps confusing me, so
let's just remove it completely from the code base.

R=leszeks@chromium.org
TBR=mstarzinger@chromium.org, verwaest@chromium.org, jgruber@chromium.org

Bug: v8:8015
Change-Id: Ibe1122fd9d2624bc94873d9c51dc8499c54a04fd
Reviewed-on: https://chromium-review.googlesource.com/1209322
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55779}
2018-09-11 09:33:18 +00:00
Georgia Kouveli
0600afddd3 [arm64] Use direct calls where possible.
This includes the following changes:
- Limit code space to 128 MB.
- Use direct branches wherever possible.
- Where not possible, continue using load literal followed by an indirect
  branch.
- Sort RelocInfo by target_address_address for the serializer, since mixing
  load literal instructions and branch instructions messes up that order.
- Ensure we always wipe out targets in the serializer (not just for the
  snapshot) in order to be able to distinguish between constant pool entries
  and branch instructions.

Change-Id: I1a1029ce2a5f72a3a94802daf267d14a42c7c790
Reviewed-on: https://chromium-review.googlesource.com/939175
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Georgia Kouveli <georgia.kouveli@arm.com>
Cr-Commit-Position: refs/heads/master@{#52885}
2018-04-30 15:02:27 +00:00
jgruber
fd70917d52 Reland "[builtins] Remove off-heap builtins from the snapshot"
This is a reland of f1b1ec70a6

Original change's description:
> [builtins] Remove off-heap builtins from the snapshot
>
> This CL is the final major step towards shipping off-heap-safe builtins
> embedded into the binary.
>
> Prior to snapshot serialization, we now:
> * create the embedded blob containing off-heap instruction streams,
> * use that to generate embedded.cc (containing embedded binary data),
> * replace off-heap-safe builtins with trampolines,
> * and serialize those into the final snapshot.
>
> The new RelocInfo::OFF_HEAP_TARGET kind is used to fix up trampoline
> targets on deserialization.
>
> Bug: v8:6666
> Change-Id: Ib07aea9e3bd7ecdec42291c1388b3a7453ea96ce
> Reviewed-on: https://chromium-review.googlesource.com/950775
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#51960}

TBR=yangguo@chromium.org,mstarzinger@chromium.org

Cq-Include-Trybots: luci.v8.try:v8_mac64_dbg,v8_mac64_rel
Bug: v8:6666
Change-Id: Id9954af3c8195754ff3658c4603858904fcf88c4
Reviewed-on: https://chromium-review.googlesource.com/964481
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52006}
2018-03-19 07:42:02 +00:00
Jakob Gruber
fda0d684c3 Revert "[builtins] Remove off-heap builtins from the snapshot"
This reverts commit f1b1ec70a6.

Reason for revert: Tentative revert for https://logs.chromium.org/v/?s=chromium%2Fbb%2Fclient.v8.fyi%2FV8-Blink_Mac%2F13696%2F%2B%2Frecipes%2Fsteps%2Fwebkit_unit_tests%2F0%2Fstdout

Original change's description:
> [builtins] Remove off-heap builtins from the snapshot
> 
> This CL is the final major step towards shipping off-heap-safe builtins
> embedded into the binary.
> 
> Prior to snapshot serialization, we now:
> * create the embedded blob containing off-heap instruction streams,
> * use that to generate embedded.cc (containing embedded binary data),
> * replace off-heap-safe builtins with trampolines,
> * and serialize those into the final snapshot.
> 
> The new RelocInfo::OFF_HEAP_TARGET kind is used to fix up trampoline
> targets on deserialization.
> 
> Bug: v8:6666
> Change-Id: Ib07aea9e3bd7ecdec42291c1388b3a7453ea96ce
> Reviewed-on: https://chromium-review.googlesource.com/950775
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#51960}

TBR=yangguo@chromium.org,mstarzinger@chromium.org,jgruber@chromium.org

Change-Id: I58dd4bf9a99d37416855b48807150e1dd9ecd9e8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:6666
Reviewed-on: https://chromium-review.googlesource.com/964363
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51962}
2018-03-15 14:25:10 +00:00
jgruber
f1b1ec70a6 [builtins] Remove off-heap builtins from the snapshot
This CL is the final major step towards shipping off-heap-safe builtins
embedded into the binary.

Prior to snapshot serialization, we now:
* create the embedded blob containing off-heap instruction streams,
* use that to generate embedded.cc (containing embedded binary data),
* replace off-heap-safe builtins with trampolines,
* and serialize those into the final snapshot.

The new RelocInfo::OFF_HEAP_TARGET kind is used to fix up trampoline
targets on deserialization.

Bug: v8:6666
Change-Id: Ib07aea9e3bd7ecdec42291c1388b3a7453ea96ce
Reviewed-on: https://chromium-review.googlesource.com/950775
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51960}
2018-03-15 13:51:29 +00:00
Marja Hölttä
88062a2cbc Reland [in-place weak refs] Add in-place weak references & migrate one WeakCell to it.
Implement in-place weak reference handling in GC.

Turn FeedbackVector::optimized_code_or_smi into an in-place weak reference (this
is the only in-place weak reference at this point).

(See bug for design doc.)

BUG=v8:7308
TBR=yangguo@chromium.org

Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I16d65dc768f10ed431252e23a0df07bee9063534
Reviewed-on: https://chromium-review.googlesource.com/948493
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51731}
2018-03-05 14:24:21 +00:00
Sigurd Schneider
73d6037c20 Revert "[in-place weak refs] Add in-place weak references & migrate one WeakCell to it."
This reverts commit 07c1e641d9.

Reason for revert: Breaks TSAN build.

https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20TSAN/builds/19784

Original change's description:
> [in-place weak refs] Add in-place weak references & migrate one WeakCell to it.
> 
> Implement in-place weak reference handling in GC.
> 
> Turn FeedbackVector::optimized_code_or_smi into an in-place weak reference (this
> is the only in-place weak reference at this point).
> 
> (See bug for design doc.)
> 
> BUG=v8:7308
> 
> Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng;master.tryserver.chromium.linux:linux_chromium_rel_ng
> Change-Id: I0f9f992cb4ee0457c40b7c868317dfb607bfb906
> Reviewed-on: https://chromium-review.googlesource.com/873638
> Commit-Queue: Marja Hölttä <marja@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Hannes Payer <hpayer@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#51722}

TBR=ulan@chromium.org,marja@chromium.org,yangguo@chromium.org,hpayer@chromium.org,mlippautz@chromium.org,ishell@chromium.org,bmeurer@chromium.org

Change-Id: I75a7dd99fbfd2f5922a6c4d2000bea2adfdeac11
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7308
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng;master.tryserver.chromium.linux:linux_chromium_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/948522
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51723}
2018-03-05 11:38:41 +00:00
Marja Hölttä
07c1e641d9 [in-place weak refs] Add in-place weak references & migrate one WeakCell to it.
Implement in-place weak reference handling in GC.

Turn FeedbackVector::optimized_code_or_smi into an in-place weak reference (this
is the only in-place weak reference at this point).

(See bug for design doc.)

BUG=v8:7308

Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng;master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I0f9f992cb4ee0457c40b7c868317dfb607bfb906
Reviewed-on: https://chromium-review.googlesource.com/873638
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51722}
2018-03-05 11:11:48 +00:00
Ulan Degenbaev
7e6d62852d [heap-profiler] Simplify snapshotting of the roots.
This replaces three passes over the roots with a single pass.
This also removes root synchronization logic.

The GC subroot index is computed from the |root| parameter of the visit
method. The new |description| parameter is used as an edge name.

Bug: chromium:811842
Change-Id: I03a9215d56b54b3eb5f7bc8b32d5b22ad091c68b
Reviewed-on: https://chromium-review.googlesource.com/916781
Reviewed-by: Alexei Filippov <alph@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51350}
2018-02-19 10:03:38 +00:00
Ulan Degenbaev
bba08b3314 [heap] Add description parameter to RootVisitor methods.
The description will be used to annotate roots in the heap snapshot.

Bug: chromium:811842
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: Ic5c9a89d1921cabddb06783f08ba63740e72820d
Reviewed-on: https://chromium-review.googlesource.com/916564
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51286}
2018-02-14 10:17:34 +00:00
Michael Starzinger
a2876b81be [heap] Simplify visitation of weak next code link field.
R=ulan@chromium.org

Change-Id: I141daeffde426a75293ffa0565c867d73a81cbfc
Reviewed-on: https://chromium-review.googlesource.com/738776
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48968}
2017-10-26 12:44:13 +00:00
Michael Starzinger
537f73e97a [heap] Move {next_code_link} into the {CodeDataContainer}.
This move the {Code::next_code_link} into the data container, making it
possible to mutate the field even when {Code} objects are protected. It
also introduces a dedicated body descriptor for the container allowing
for tagged fields to be part of the container.

R=ulan@chromium.org
BUG=v8:6792

Change-Id: I56a9d53e8bb35aeb0a7036e3abf3ebee1ba2928d
Reviewed-on: https://chromium-review.googlesource.com/738184
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48966}
2017-10-26 11:58:57 +00:00
Marja Hölttä
bb514c426b [objects.h splitting] Move ObjectVisitor.
There was a helpful TODO telling where it should live.

BUG=v8:5402,v8:6921

Change-Id: Id9022c72c9e7de8d76ea0db964217b766299195d
Reviewed-on: https://chromium-review.googlesource.com/718337
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48524}
2017-10-13 09:16:07 +00:00
Michael Lippautz
204d19b2bd [heap] Cleanup some includes
Bug: 
Change-Id: I857f8b3f992faf950917060b3fe705bdd45c3ada
Reviewed-on: https://chromium-review.googlesource.com/638339
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47653}
2017-08-28 17:28:58 +00:00
Ulan Degenbaev
40c34606a7 [heap] Instrument mark-compact to track retaining paths for debugging.
This patch adds a new intrinsic: %DebugTrackRetainingPath(object).
Calling the intrinsic in JS code saves a weak reference to the given
object in GC internal table of tracked objects.

Each subsequent full GC prints to stdout the retaining path for each
tracked object (if it is still alive). The retaining path is the real
path that the marker took from the root set to the tracked object.

This is useful for investigating of memory leaks:
1) Add %DebugTrackRetainingPath(leaking_object) in JS code.
For example:
  function foo() {
    let x = { bar: "bar"};
    %DebugTrackRetainingPath(x);
    return () => { return x; }
  }

  let closure = foo();
  gc();

2) Run d8 with --allow-natives-syntax --track-retaining-path --expose-gc.

3) Check the retaining path in stdout.

For more detailed inspection, run d8 in gdb and set breakpoint in

v8: :internal::Heap::PrintRetainingPath.
Change-Id: I01a0faac1e009bc6c321fa75613900b49d2b036f
Reviewed-on: https://chromium-review.googlesource.com/575972
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46766}
2017-07-19 14:06:59 +00:00
ulan
c59f78f611 Add a host parameter to ObjectVisitor methods.
This makes an ObjectVisitor as powerful as a StaticVisitor and allows
slots recording in ObjectVisitor.

This patch also renames VisitCell method of ObjectVisitor to
VisitCellPointer, so that VisitCell is free to be used for actually
visiting a cell.

BUG=chromium:709075

Review-Url: https://codereview.chromium.org/2810653002
Cr-Commit-Position: refs/heads/master@{#44860}
2017-04-25 14:19:00 +00:00
ulan
e671ed3610 Decouple root visitors from object visitors.
This patch adds a new interface called RootVisitor and changes the root
iteration functions to accept a RootVisitor instead of an ObjectVisitor.

Future CLs will change ObjectVisitor to provide the host object to all
visiting functions, which will bring it in sync with static visitors.

Having separate visitors for roots and objects removes ambiguity in
VisitPointers and reduces chances of forgetting to record slots.

This is intended as pure refactoring. All places that require behavior
change are marked with TODO and will addressed in future CLs.

BUG=chromium:709075

Review-Url: https://codereview.chromium.org/2801073006
Cr-Commit-Position: refs/heads/master@{#44852}
2017-04-25 13:32:18 +00:00