This CL adds --trace-precompiler-to option which generates a machine readable
precompiler trace (list of all compiled functions and their dependencies).
It also expands package:vm_snapshot_analysis with tools for reading and
analysing this trace.
For example snapshot_analysis explain dynamic-calls command allows
to list all dynamic calls sorted by their impact on the size of the AOT
snapshot.
Issue https://github.com/dart-lang/sdk/issues/41249
Cq-Include-Trybots: luci.dart.try:pkg-linux-debug-try,pkg-linux-release-try,pkg-win-release-try,pkg-mac-release-try
Change-Id: Ie49143f4da375067991991e2ad20a41ec67bb1c3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/152851
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Adds another interface target to instance calls, pointing to the torn
off method for tearoff getter calls. This is then used to direct the
call to the method extractor for the method.
Increases the fraction of dynamically dispatched instance calls in
Flutter Gallery that are handled by the dispatch table from 95.8% to
98.4%. The remaining 92 IC calls are all on static receiver type
dynamic or Function (34 function calls, 22 method calls, 21 operator
calls, 14 getter calls and 1 setter call).
Change-Id: I0bde1a8271c8563f4631534bd39d1254cd779380
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/142155
Commit-Queue: Aske Simon Christensen <askesc@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
#if defined(DART_PRECOMPILED_RUNTIME)
#error "AOT runtime should not use compiler sources (including header files)"
#endif // defined(DART_PRECOMPILED_RUNTIME)
Remove #if defined(DART_PRECOMPILED_RUNTIME) from most compiler sources.
Change-Id: Id175c83fdbea38d9d5e1371ff433e3888f2afe8a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/143523
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
These changes were originally submitted separately on different days,
and a major performance regression was seen after the first change
when creating snapshots that led to both being reverted. However,
that performance regression should be addressed by the followup.
First change:
"[vm] Treat the dispatch table as a root in the snapshot.
Additional changes:
* Only serialize a dispatch table in precompiled snapshots.
* Add information in v8 snapshot profiles for the dispatch table.
* Fix a typo in a field name.
* Print the number of Instructions objects (or payloads, for
precompiled bare instructions mode) in the fake cluster for
the data section.
* Fix v8 snapshots profiles so objects in memory mapped segments
and only those are prefixed with "(RO) ".
* Add names for Instructions objects in v8 snapshot profiles
when we can use the assembly namer.
* Add command line flag for old #define'd false flag."
Second change:
"[vm/aot] Keep GC-visible references to dispatch table Code entries.
This change splits dispatch table handling into four distinct
parts:
* The dispatch table generator does not make a dispatch table
directly, but rather creates an Array that contains the Code
objects for dispatch table entries.
* The precompiler takes this Array and puts it in the object
store, which makes it a new GC root.
* The serializer takes this information and serializes the
dispatch table information in the same form as before.
* The deserializer creates a DispatchTable object and populates
it using the serialized information.
The change in the precompiler ensures that the Code objects
used in the dispatch table have GC-visible references. Thus,
even if all other references to them from the other GC roots
were removed, they would be accessible in the serializer in
the case of a GC pass between the precompiler and serializer.
This change also means that the serializer can retrieve and
trace the Code objects directly rather than first looking up
the Code objects by their entry point."
Bug: https://github.com/dart-lang/sdk/issues/41022
Change-Id: I52c83b0536fc588da0bef9aed1f0c72e8ee4663f
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-linux-release-simarm-try,vm-kernel-precomp-linux-release-simarm64-try,vm-kernel-precomp-linux-release-simarm_x64-try,vm-kernel-precomp-android-release-arm64-try,vm-kernel-precomp-android-release-arm_x64-try,vm-kernel-precomp-mac-release-simarm64-try,vm-kernel-precomp-win-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/139285
Commit-Queue: Teagan Strickland <sstrickl@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
This change splits dispatch table handling into four distinct
parts:
* The dispatch table generator does not make a dispatch table
directly, but rather creates an Array that contains the Code
objects for dispatch table entries.
* The precompiler takes this Array and puts it in the object
store, which makes it a new GC root.
* The serializer takes this information and serializes the
dispatch table information in the same form as before.
* The deserializer creates a DispatchTable object and populates
it using the serialized information.
The change in the precompiler ensures that the Code objects
used in the dispatch table have GC-visible references. Thus,
even if all other references to them from the other GC roots
were removed, they would be accessible in the serializer in
the case of a GC pass between the precompiler and serializer.
This change also means that the serializer can retrieve and
trace the Code objects directly rather than first looking up
the Code objects by their entry point.
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-linux-release-simarm-try,vm-kernel-precomp-linux-release-simarm64-try,vm-kernel-precomp-linux-release-simarm_x64-try,vm-kernel-precomp-android-release-arm64-try,vm-kernel-precomp-android-release-arm_x64-try,vm-kernel-precomp-mac-release-simarm64-try,vm-kernel-precomp-win-release-x64-try
Change-Id: Ic9ba29dfd64945a6e9a51f9de73f74d9202b58b7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/138288
Commit-Queue: Teagan Strickland <sstrickl@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Aske Simon Christensen <askesc@google.com>
NullCheck pc descriptors are added to all dispatch table calls where the
receiver may be null (and the selector is not one implemented by null).
All null entries in the table go to the NullError runtime entry, which
reads the NullCheck pc descriptor to get the name of the called member
for the error message.
Change-Id: I9d2847d0ccdfdb735b06e879916920ec299f39bc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/134294
Commit-Queue: Aske Simon Christensen <askesc@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
The instruction sequences for dispatch table calls have three versions,
depending on the selector offset relative to where the dispatch table
register is pointing:
- Optimal: Zero offset
- Small: A small range of positive and negative offsets
- Large: Larger positive offsets
The exact limits for small offsets depend on the target architecture.
This commit changes the dispatch table layout algorithm to favor
offsets corresponding to smaller instruction sequences for selectors
with many callsites.
As a result, == (which is by far the most abundantly called selector)
gets the zero offset, and most commonly used selectors (such as [],
iterator, current and moveNext) usually get small offsets on ARM and
ARM64 targets (where the range of small offsets is reasonably large).
Change-Id: I4be9ef8e709c71681b5743084f280ce1673bc0ad
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/132663
Reviewed-by: Martin Kustermann <kustermann@google.com>
For each selector, count the number of calls to the selector that are
both reachable and polymorphic according to the TFA. Only include
selectors in the table with non-zero counts.
This reduces the dispatch table size by 30% in dart2js and by 49% in
Flutter Gallery (312k memory use reduction on ARM64).
Call counts are transferred in a dedicated metadata block with
per-selector information. This mechanism also prepares for transferring
other per-selector information in the future.
Change-Id: Iba15aa4d6c50e67e53c3fd8e542123d3fc98bd07
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/132603
Reviewed-by: Alexander Markov <alexmarkov@google.com>
This is a Dart-tailored implementation of the "row-displacement
dispatch table" technique for closed-world instance calls:
All interface targets in the program are grouped into selectors such
that all targets that could potentially be called from the same call
site have the same selector (currently just grouped by name).
Each selector is assigned a selector offset such that offset + classid
is unique for all selector/classid combinations where the class
implements the selector.
At every instance call site that has an interface target (i.e. where
the static type of the receiver is not dynamic), the selector offset +
receiver classid is computed and used as index into a global table of
entry points.
If the receiver can be null (as determined by the front-end TFA and the
VM type propagation), a null check is inserted before the call.
An arguments descriptor is provided (only) for selectors that need it
(those which have type parameters or optional/named parameters).
The dispatch table calls don't need the monomorphic entry code, so for
functions that are only called via dispatch table calls (i.e. never
called dynamically), the monomorphic entry code is left out.
Some future improvements to the table dispatch implementation are
mentioned in https://github.com/dart-lang/sdk/issues/40188
The table dispatch flag is disabled by default in this commit. A
separate commit enables the flag.
Change-Id: Ic2911742b4a2c9a8d3bc7df60605454cbe4c0714
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/126648
Commit-Queue: Aske Simon Christensen <askesc@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Vyacheslav Egorov