Unlike the assembler, the register allocator is in a position to avoid a move. Use the call result register since it is the most popular value source.
This pattern will also be needed to get the write barrier slot into a fixed register for card-marking, since X64 and ARM don't have a TMP2.
dart2js aot product:
X64 Instructions(CodeSize): 9049952 -> 8994240 (-0.62%)
ARM Instructions(CodeSize): 9772096 -> 9711696 (-0.62%)
ARM64 Instructions(CodeSize): 10185056 -> 10122496 (-0.61%)
Bug: https://github.com/dart-lang/sdk/issues/34002
Change-Id: Id2e9dd7b3d86069a9da3ba4e141720511ce6399e
Reviewed-on: https://dart-review.googlesource.com/76307
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
This allows building a core-jit snapshot that can support running with
--enable-interpreter even when the core-jit snapshot is not generated
with --enable-interpreter.
Change-Id: If6ce787baa9f11fef929ee496b54d68598cba520
Reviewed-on: https://dart-review.googlesource.com/75989
Reviewed-by: Régis Crelier <regis@google.com>
Commit-Queue: Zach Anderson <zra@google.com>
After this CL, the interpreter is included by default in the
JIT VM under the flag --enable-interpreter.
Reland with fix to NativeArgument setup in simulator_arm.cc
Change-Id: Ib9b4df6eb4d997dfbe361188b8a127828c1d9c6f
Reviewed-on: https://dart-review.googlesource.com/74003
Reviewed-by: Siva Annamalai <asiva@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
Commit-Queue: Zach Anderson <zra@google.com>
Test Plan:
Behavioral correctness should be ensured by existing tests. Tests in vm/dart/entrypoints
ensure that the unchecked entrypoint is used in cases where the optimization should trigger.
Bug: https://github.com/dart-lang/sdk/issues/31798
Change-Id: I5b880b2dfa6343b4bb0a96ad23562facff73e41f
Cq-Include-Trybots: luci.dart.try:vm-kernel-win-release-x64-try,vm-kernel-optcounter-threshold-linux-release-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-release-simarm-try,vm-kernel-precomp-linux-release-simarm64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-win-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/69741
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
There is no difference from the previous version of this CL.
This depends on https://dart-review.googlesource.com/c/sdk/+/67220/3 which fixes a bug
in `CompileType` that was causing `ShouldEmitStoreBarrier()` to return different results
across multiple calls on the same instruction.
The buildbot on which this caused a failure is run as a tryjob below.
Change-Id: I078b587f7e23e88d95f3b05c966019a433ba57d9
Reviewed-on: https://dart-review.googlesource.com/67221
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
This reverts commit 79ed0553e9.
Reason for revert: Issue with register allocator on SIMARM.
Original change's description:
> Re-land "[vm] Factor out more of the slow-path of the store barrier into the stubs."
>
> When compiling instrinsic graphs on ARM and ARM64 we need to save LR when emitting
> the store barrier because the intrinsics don't have frames and won't restore it before
> returning.
>
> Original revision is in Patchset 1.
>
> Change-Id: I58cee3941c82efa22bd6ddbd00e00c489de53898
> Cq-Include-Trybots: luci.dart.try: vm-kernel-optcounter-threshold-linux-release-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-release-simarm-try,vm-kernel-precomp-linux-release-simarm64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-win-release-x64-try,vm-kernel-linux-release-simarm-try,vm-kernel-linux-release-simarm64-try
> Reviewed-on: https://dart-review.googlesource.com/66382
> Commit-Queue: Samir Jindel <sjindel@google.com>
> Reviewed-by: Alexander Markov <alexmarkov@google.com>
TBR=alexmarkov@google.com,sjindel@google.com
# Not skipping CQ checks because original CL landed > 1 day ago.
Change-Id: If8f8bc1a508f300ab83b03a0be7e0c318e5f99fe
Cq-Include-Trybots: luci.dart.try: vm-kernel-optcounter-threshold-linux-release-x64-try, vm-kernel-precomp-linux-debug-x64-try, vm-kernel-precomp-linux-release-simarm-try, vm-kernel-precomp-linux-release-simarm64-try, vm-kernel-precomp-linux-release-x64-try, vm-kernel-precomp-win-release-x64-try, vm-kernel-linux-release-simarm-try, vm-kernel-linux-release-simarm64-try
Reviewed-on: https://dart-review.googlesource.com/67140
Reviewed-by: Samir Jindel <sjindel@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Samir Jindel <sjindel@google.com>
When compiling instrinsic graphs on ARM and ARM64 we need to save LR when emitting
the store barrier because the intrinsics don't have frames and won't restore it before
returning.
Original revision is in Patchset 1.
Change-Id: I58cee3941c82efa22bd6ddbd00e00c489de53898
Cq-Include-Trybots: luci.dart.try: vm-kernel-optcounter-threshold-linux-release-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-release-simarm-try,vm-kernel-precomp-linux-release-simarm64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-win-release-x64-try,vm-kernel-linux-release-simarm-try,vm-kernel-linux-release-simarm64-try
Reviewed-on: https://dart-review.googlesource.com/66382
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
This reverts commit b3e289a95e.
Reason for revert: multiple failures on *-simarm, *-simarm64 and vm-precomp-android-release-2-3-be bots.
Original change's description:
> [vm] Factor out more of the slow-path of the store barrier into the stubs.
>
> This delivers a 2.1% code size reduction on Flutter Gallery, and roughly 1.6% speed
> improvement on dart2js(dart2js).
>
> Cq-Include-Trybots: luci.dart.try: vm-kernel-optcounter-threshold-linux-release-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-release-simarm-try,vm-kernel-precomp-linux-release-simarm64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-win-release-x64-try
> Change-Id: I2d2ceca8707d5e6fba79c558624d611f9e17d21a
> Reviewed-on: https://dart-review.googlesource.com/65060
> Commit-Queue: Samir Jindel <sjindel@google.com>
> Reviewed-by: Alexander Markov <alexmarkov@google.com>
TBR=alexmarkov@google.com,sjindel@google.com
Change-Id: Iae83a5108d56cbd30e5727217b5ee043449f82ff
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Cq-Include-Trybots: luci.dart.try: vm-kernel-optcounter-threshold-linux-release-x64-try, vm-kernel-precomp-linux-debug-x64-try, vm-kernel-precomp-linux-release-simarm-try, vm-kernel-precomp-linux-release-simarm64-try, vm-kernel-precomp-linux-release-x64-try, vm-kernel-precomp-win-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/66360
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
The stub was marking the thread as executing VM code too early, since the slow
path of AllocateArray (called via PushArrayOfArguments) calls into the runtime.
With this fix, DeltaBlueClosures can run in fully interpreted mode.
Change-Id: I16f8e93fe0c1ee02dd284a19971eee4915f47c28
Reviewed-on: https://dart-review.googlesource.com/63500
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Régis Crelier <regis@google.com>
This reverts commit dff333e1bf.
Reason for revert: Several hot-reload bots are broken.
Original change's description:
> [vm/precomp] Support slow-path sharing for CheckStackOverflow.
>
> Test Plan:
>
> Added new test "stack_overflow_shared_test" which uses --stacktrace_filter to
> force the stack overflow checks to go into the slow-path.
>
> Change-Id: I92e8ab5f88b1e0855148af212e43adda40ce4d15
> Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-debug-x64-try;luci.dart.try:vm-kernel-precomp-linux-release-x64-try;luci.dart.try:vm-kernel-precomp-linux-release-simarm-try
> Reviewed-on: https://dart-review.googlesource.com/60340
> Commit-Queue: Samir Jindel <sjindel@google.com>
> Reviewed-by: Alexander Markov <alexmarkov@google.com>
TBR=alexmarkov@google.com,sjindel@google.com
Change-Id: I632ac9840d360fa624de4c9d17ae679e72c1b16f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-debug-x64-try;luci.dart.try:vm-kernel-precomp-linux-release-x64-try;luci.dart.try:vm-kernel-precomp-linux-release-simarm-try
Reviewed-on: https://dart-review.googlesource.com/62920
Reviewed-by: Samir Jindel <sjindel@google.com>
Commit-Queue: Samir Jindel <sjindel@google.com>
Test Plan:
Added new test "stack_overflow_shared_test" which uses --stacktrace_filter to
force the stack overflow checks to go into the slow-path.
Change-Id: I92e8ab5f88b1e0855148af212e43adda40ce4d15
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-debug-x64-try;luci.dart.try:vm-kernel-precomp-linux-release-x64-try;luci.dart.try:vm-kernel-precomp-linux-release-simarm-try
Reviewed-on: https://dart-review.googlesource.com/60340
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
When the slow path code of StackOverflowInstr is calling out to runtime
and the runtime causes a lazy-deopt, the lazy deopt stub will treat the value in the
return-value-register as GC-safe and the value will be visited during GCs.
This CL changes the call-to-runtime-stub to always put 0 into the
return-value-register.
This should fix the flaky vm-linux-debug-x64-reload-be builder.
Change-Id: Ibea3630b8b9fa5de2b96134725df0017c09282bd
Reviewed-on: https://dart-review.googlesource.com/60661
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
The stub code for calling into the runtime is now responsible for saving any
live registers. Since it doesn't know which registers are live (it's shared
across many safepoints), it saves all the registers. The stackmaps and
environments for safepoints which call this stub are extended to cover the stack
slots in the stub's frame which correspond to registers which are actually live
at the safepoint.
Currently this is only supported in precompiled X64 for the `CheckNull`
slow-path. By creating a separate stub for the CheckNull slow path we are able
to eliminate the size overhead of preparing arguments for the runtime call stub,
and reduce the slow-path size on X64 to 1 instruction.
# Test Plan
The stackmap for a safepoint in the `CheckNull` slowpath is only used when
handling the exception causes a GC, which is extremely unlikely. To induce this,
we add a flag to force this behavior in debug-mode and a test which exercises
this. The rest of the changes inherit existing coverage.
Change-Id: I3d8f2a7c3560c432599344d7420d42ddbee7a89d
Reviewed-on: https://dart-review.googlesource.com/59660
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Samir Jindel <sjindel@google.com>
Relanding 4be50d6fa1 with fixes to DBC
and location summaries: AssertAssignable must save FPU registers.
For now we are limiting this to type checks against type parameter types.
In Dart 1 mode Dart2JS compiles itself in 28s when running from source
and in 23s when running from ideal app-jit snapshot (trained on the
same workload).
Before this change in Dart 2 mode numbers were 51s and 57s respectively.
After this change in Dart 2 mode numbers are 38s and 32s. Meaning
that regression is reduced by 50%.
Issue https://github.com/dart-lang/sdk/issues/31798
Issue https://github.com/dart-lang/sdk/issues/33257
Change-Id: Ifb55f86453bfdf36a2e03bcd7f3197cfde257103
Reviewed-on: https://dart-review.googlesource.com/57980
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
This reverts commit 4be50d6fa1.
Reason for revert: Failures on SIMDBC64 and Analyzer bots.
Original change's description:
> [vm] Enable type stubs based type checks in JIT mode for some types.
>
> For now we are limiting this to type checks against type parameter types.
>
> # Performance improvements
>
> In Dart 1 mode Dart2JS compiles itself in 28s when running from source
> and in 23s when running from ideal app-jit snapshot (trained on the
> same workload).
>
> Before this change in Dart 2 mode numbers were 51s and 57s respectively.
>
> After this change in Dart 2 mode numbers are 38s and 32s. Meaning
> that regression is reduced by 50%.
>
> Issue https://github.com/dart-lang/sdk/issues/31798
> Issue https://github.com/dart-lang/sdk/issues/33257
>
> Change-Id: I34bf5385a5cc3c7702dc281c6dfa89da85d3dde1
> Reviewed-on: https://dart-review.googlesource.com/57601
> Reviewed-by: Régis Crelier <regis@google.com>
> Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
TBR=vegorov@google.com,kustermann@google.com,regis@google.com
Change-Id: I85a30c962b0cd556310e19193f5993ab76ecf2e7
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/57840
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
For now we are limiting this to type checks against type parameter types.
# Performance improvements
In Dart 1 mode Dart2JS compiles itself in 28s when running from source
and in 23s when running from ideal app-jit snapshot (trained on the
same workload).
Before this change in Dart 2 mode numbers were 51s and 57s respectively.
After this change in Dart 2 mode numbers are 38s and 32s. Meaning
that regression is reduced by 50%.
Issue https://github.com/dart-lang/sdk/issues/31798
Issue https://github.com/dart-lang/sdk/issues/33257
Change-Id: I34bf5385a5cc3c7702dc281c6dfa89da85d3dde1
Reviewed-on: https://dart-review.googlesource.com/57601
Reviewed-by: Régis Crelier <regis@google.com>
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
This reverts commit cf78da8a48.
Reason for revert: introduces significant performance regression (~30%) on analyzer benchmarks (warm-analysis) without clearly visible hot-spot.
Original change's description:
> [VM] Reduce Smi size to 32 bit on 64 bit platforms
>
> This reduces small tagged integers on 64 bit platforms from 63 bits to
> 31 bits plus one tag bit.
> This is a step on the way to compile-time-optional compressed pointers
> on 64 bit platforms. See more about this at go/dartvmlearnings
> This causes a slowdown for some uses of integers that don't fit in 31
> signed bits, but because both x64 and ARM64 have unboxed 64 bit
> integers now the performance hit should not be too bad.
>
> This is a reapplication of
> https://dart-review.googlesource.com/c/sdk/+/46244
> It was reverted due to a compilation error on 32 bit
> ARM with DBC.
>
> R=vegorov@google.com
>
> Change-Id: I943de1768519457f0e5a61ef0b4ef204b6a53281
> Reviewed-on: https://dart-review.googlesource.com/51321
> Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
TBR=vegorov@google.com,erikcorry@google.com
# Not skipping CQ checks because original CL landed > 1 day ago.
Change-Id: I8c5b909ec38663b5f5b05f69ef488c97341f8f3d
Reviewed-on: https://dart-review.googlesource.com/54000
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
This reduces small tagged integers on 64 bit platforms from 63 bits to
31 bits plus one tag bit.
This is a step on the way to compile-time-optional compressed pointers
on 64 bit platforms. See more about this at go/dartvmlearnings
This causes a slowdown for some uses of integers that don't fit in 31
signed bits, but because both x64 and ARM64 have unboxed 64 bit
integers now the performance hit should not be too bad.
This is a reapplication of
https://dart-review.googlesource.com/c/sdk/+/46244
It was reverted due to a compilation error on 32 bit
ARM with DBC.
R=vegorov@google.com
Change-Id: I943de1768519457f0e5a61ef0b4ef204b6a53281
Reviewed-on: https://dart-review.googlesource.com/51321
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Relands 165c583d57
[VM] Introduction of type testing stubs - Part 1
This CL:
* Adds a field to [RawAbstractType] which will always hold a pointer
to the entrypoint of a type testing stub
* Makes this new field be initialized to a default stub whenever a
instances are created (e.g. via Type::New(), snapshot reader, ...)
* Makes the clustered snapshotter write a reference to the
corresponding [RawInstructions] object when writing the field and do
the reverse when reading it.
* Makes us call the type testing stub for performing assert-assignable
checks.
To reduce unnecessary loads on callsites, we store the entrypoint of the
type testing stubs directly in the type objects. This means that the
caller of type testing stubs can simply branch there without populating
a code object first. This also means that the type testing stubs
themselves have no access to a pool and we therefore also don't hold on
to the [Code] object, only the [Instruction] object is necessary.
The type testing stubs do not setup a frame themselves and also have no
safepoint. In the case when the type testing stubs could not determine
a positive answer they will tail-call a general-purpose stub.
The general-purpose stub sets up a stub frame, tries to consult a
[SubtypeTestCache] and bails out to runtime if this was unsuccessful.
This CL is just the the first, for ease of reviewing. The actual
type-specialized type testing stubs will be generated in later CLs.
Reviewed-on: https://dart-review.googlesource.com/44787
Relands f226c22424
[VM] Introduction of type testing stubs - Part 2
This CL starts building type testing stubs specialzed for [Type] objects
we test against.
More specifically, it adds support for:
* Handling obvious fast cases on the call sites (while still having a
call to stub for negative case)
* Handling type tests against type parameters, by loading the value
of the type parameter on the call sites and invoking it's type testing stub.
* Specialzed type testing stubs for instantiated types where we can
do [CidRange]-based subtype-checks.
==> e.g. String/List<dynamic>
* Specialzed type testing stubs for instantiated types where we can
do [CidRange]-based subclass-checks for the class and
[CidRange]-based subtype-checks for the type arguments.
==> e.g. Widget<State>, where we know [Widget] is only extended and not
implemented.
* Specialzed type testing stubs for certain non-instantiated types where we
can do [CidRange]-based subclass-checks for the class and
[CidRange]-based subtype-checks for the instantiated type arguments and
cid based comparisons for type parameters. (Note that this fast-case migth
result in some false-negatives!)
==> e.g. _HashMapEntry<K, V>, where we know [_HashMapEntry] is only
extended and not implemented.
This optimizes cases where the caller uses `new HashMap<A, B>()` and only
uses `A` and `B` as key/values (and not subclasses of it). The false-negative
can occur when subtypes of A or B are used. In such cases we fall back to the
[SubtypeTestCache]-based imlementation.
Reviewed-on: https://dart-review.googlesource.com/44788
Relands 25f98bcc75
[VM] Introduction of type testing stubs - Part 3
The changes include:
* Make AssertAssignableInstr no longer have a call-summary, which
helps methods with several parameter checks by not having to
re-load/re-initialize type arguments registers
* Lazily create SubtypeTestCaches: We already go to runtime to warm up
the caches, so we now also create the caches on the first runtime
call and patch the pool entries.
* No longer load the destination name into a register: We only need
the name when we throw an exception, so it is not on the hot path.
Instead we let the runtime look at the call site, decoding a pool
index from the instructions stream. The destination name will be
available in the pool, at a consecutive index to the subtype cache.
* Remove the fall-through to N=1 case for probing subtypeing tests,
since those will always be handled by the optimized stubs.
* Do not generate optimized stubs for FutureOr<T> (so far it just
falled-through to TTS). We can make optimzed version of that later,
but it requires special subtyping rules.
* Local code quality improvement in the type-testing-stubs: Avoid
extra jump at last case of cid-class-range checks.
There are still a number of optimization opportunities we can do in
future changes.
Reviewed-on: https://dart-review.googlesource.com/46984
Relands 2c52480ec8
[VM] Introduction of type testing stubs - Part 4
In order to avoid generating type testing stubs for too many types in
the system - and thereby potentially cause an increase in code size -
this change introduces a smarter way to decide for which types we should
generate optimized type testing stubs.
The precompiler creates a [TypeUsageInfo] which we use to collect
information. More specifically:
a) We collect the destination types for all type checks we emit
(we do this inside AssertAssignableInstr::EmitNativeCode).
-> These are types we might want to generate optimized type testing
stubs for.
b) We collect type argument vectors used in instance creations (we do
this inside AllocateObjectInstr::EmitNativeCode) and keep a set of
of used type argument vectors for each class.
After the precompiler has finished compiling normal code we scan the set
of destination types collected in a) for uninstantiated types (or more
specifically, type parameter types).
We then propagate the type argument vectors used on object allocation sites,
which were collected in b), in order to find out what kind of types are flowing
into those type parameters.
This allows us to extend the set of types which we test against, by
adding the types that flow into type parameters.
We use this final augmented set of destination types as a "filter" when
making the decision whether to generate an optimized type testing stub
for a given type.
Reviewed-on: https://dart-review.googlesource.com/48640
Issue https://github.com/dart-lang/sdk/issues/32603
Closes https://github.com/dart-lang/sdk/issues/32852
Change-Id: Ib79fbe7f043aa88f32bddad62d7656c638914b44
Reviewed-on: https://dart-review.googlesource.com/50944
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
Relands 165c583d57
[VM] Introduction of type testing stubs - Part 1
This CL:
* Adds a field to [RawAbstractType] which will always hold a pointer
to the entrypoint of a type testing stub
* Makes this new field be initialized to a default stub whenever a
instances are created (e.g. via Type::New(), snapshot reader, ...)
* Makes the clustered snapshotter write a reference to the
corresponding [RawInstructions] object when writing the field and do
the reverse when reading it.
* Makes us call the type testing stub for performing assert-assignable
checks.
To reduce unnecessary loads on callsites, we store the entrypoint of the
type testing stubs directly in the type objects. This means that the
caller of type testing stubs can simply branch there without populating
a code object first. This also means that the type testing stubs
themselves have no access to a pool and we therefore also don't hold on
to the [Code] object, only the [Instruction] object is necessary.
The type testing stubs do not setup a frame themselves and also have no
safepoint. In the case when the type testing stubs could not determine
a positive answer they will tail-call a general-purpose stub.
The general-purpose stub sets up a stub frame, tries to consult a
[SubtypeTestCache] and bails out to runtime if this was unsuccessful.
This CL is just the the first, for ease of reviewing. The actual
type-specialized type testing stubs will be generated in later CLs.
Reviewed-on: https://dart-review.googlesource.com/44787
Relands f226c22424
[VM] Introduction of type testing stubs - Part 2
This CL starts building type testing stubs specialzed for [Type] objects
we test against.
More specifically, it adds support for:
* Handling obvious fast cases on the call sites (while still having a
call to stub for negative case)
* Handling type tests against type parameters, by loading the value
of the type parameter on the call sites and invoking it's type testing stub.
* Specialzed type testing stubs for instantiated types where we can
do [CidRange]-based subtype-checks.
==> e.g. String/List<dynamic>
* Specialzed type testing stubs for instantiated types where we can
do [CidRange]-based subclass-checks for the class and
[CidRange]-based subtype-checks for the type arguments.
==> e.g. Widget<State>, where we know [Widget] is only extended and not
implemented.
* Specialzed type testing stubs for certain non-instantiated types where we
can do [CidRange]-based subclass-checks for the class and
[CidRange]-based subtype-checks for the instantiated type arguments and
cid based comparisons for type parameters. (Note that this fast-case migth
result in some false-negatives!)
==> e.g. _HashMapEntry<K, V>, where we know [_HashMapEntry] is only
extended and not implemented.
This optimizes cases where the caller uses `new HashMap<A, B>()` and only
uses `A` and `B` as key/values (and not subclasses of it). The false-negative
can occur when subtypes of A or B are used. In such cases we fall back to the
[SubtypeTestCache]-based imlementation.
Reviewed-on: https://dart-review.googlesource.com/44788
Relands 25f98bcc75
[VM] Introduction of type testing stubs - Part 3
The changes include:
* Make AssertAssignableInstr no longer have a call-summary, which
helps methods with several parameter checks by not having to
re-load/re-initialize type arguments registers
* Lazily create SubtypeTestCaches: We already go to runtime to warm up
the caches, so we now also create the caches on the first runtime
call and patch the pool entries.
* No longer load the destination name into a register: We only need
the name when we throw an exception, so it is not on the hot path.
Instead we let the runtime look at the call site, decoding a pool
index from the instructions stream. The destination name will be
available in the pool, at a consecutive index to the subtype cache.
* Remove the fall-through to N=1 case for probing subtypeing tests,
since those will always be handled by the optimized stubs.
* Do not generate optimized stubs for FutureOr<T> (so far it just
falled-through to TTS). We can make optimzed version of that later,
but it requires special subtyping rules.
* Local code quality improvement in the type-testing-stubs: Avoid
extra jump at last case of cid-class-range checks.
There are still a number of optimization opportunities we can do in
future changes.
Reviewed-on: https://dart-review.googlesource.com/46984
Relands 2c52480ec8
[VM] Introduction of type testing stubs - Part 4
In order to avoid generating type testing stubs for too many types in
the system - and thereby potentially cause an increase in code size -
this change introduces a smarter way to decide for which types we should
generate optimized type testing stubs.
The precompiler creates a [TypeUsageInfo] which we use to collect
information. More specifically:
a) We collect the destination types for all type checks we emit
(we do this inside AssertAssignableInstr::EmitNativeCode).
-> These are types we might want to generate optimized type testing
stubs for.
b) We collect type argument vectors used in instance creations (we do
this inside AllocateObjectInstr::EmitNativeCode) and keep a set of
of used type argument vectors for each class.
After the precompiler has finished compiling normal code we scan the set
of destination types collected in a) for uninstantiated types (or more
specifically, type parameter types).
We then propagate the type argument vectors used on object allocation sites,
which were collected in b), in order to find out what kind of types are flowing
into those type parameters.
This allows us to extend the set of types which we test against, by
adding the types that flow into type parameters.
We use this final augmented set of destination types as a "filter" when
making the decision whether to generate an optimized type testing stub
for a given type.
Reviewed-on: https://dart-review.googlesource.com/48640
Issue https://github.com/dart-lang/sdk/issues/32603
Change-Id: I6d33d4ca3d5187a1eb1664078c003061855f0160
Reviewed-on: https://dart-review.googlesource.com/50482
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
This reduces small tagged integers on 64 bit platforms from 63 bits to
31 bits plus one tag bit.
This is a step on the way to compile-time-optional compressed pointers
on 64 bit platforms. See more about this at go/dartvmlearnings
This causes a slowdown for some uses of integers that don't fit in 31
signed bits, but because both x64 and ARM64 have unboxed 64 bit
integers now the performance hit should not be too bad.
This reapplies the change reviewed at
https://dart-review.googlesource.com/c/sdk/+/46244R=kustermann@google.com
Change-Id: I605c21506ec7d4c69fa7049bc419b3ee370685fc
Reviewed-on: https://dart-review.googlesource.com/50202
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Erik Corry <erikcorry@google.com>
Relands 165c583d57
[VM] Introduction of type testing stubs - Part 1
This CL:
* Adds a field to [RawAbstractType] which will always hold a pointer
to the entrypoint of a type testing stub
* Makes this new field be initialized to a default stub whenever a
instances are created (e.g. via Type::New(), snapshot reader, ...)
* Makes the clustered snapshotter write a reference to the
corresponding [RawInstructions] object when writing the field and do
the reverse when reading it.
* Makes us call the type testing stub for performing assert-assignable
checks.
To reduce unnecessary loads on callsites, we store the entrypoint of the
type testing stubs directly in the type objects. This means that the
caller of type testing stubs can simply branch there without populating
a code object first. This also means that the type testing stubs
themselves have no access to a pool and we therefore also don't hold on
to the [Code] object, only the [Instruction] object is necessary.
The type testing stubs do not setup a frame themselves and also have no
safepoint. In the case when the type testing stubs could not determine
a positive answer they will tail-call a general-purpose stub.
The general-purpose stub sets up a stub frame, tries to consult a
[SubtypeTestCache] and bails out to runtime if this was unsuccessful.
This CL is just the the first, for ease of reviewing. The actual
type-specialized type testing stubs will be generated in later CLs.
Reviewed-on: https://dart-review.googlesource.com/44787
Relands f226c22424
[VM] Introduction of type testing stubs - Part 2
This CL starts building type testing stubs specialzed for [Type] objects
we test against.
More specifically, it adds support for:
* Handling obvious fast cases on the call sites (while still having a
call to stub for negative case)
* Handling type tests against type parameters, by loading the value
of the type parameter on the call sites and invoking it's type testing stub.
* Specialzed type testing stubs for instantiated types where we can
do [CidRange]-based subtype-checks.
==> e.g. String/List<dynamic>
* Specialzed type testing stubs for instantiated types where we can
do [CidRange]-based subclass-checks for the class and
[CidRange]-based subtype-checks for the type arguments.
==> e.g. Widget<State>, where we know [Widget] is only extended and not
implemented.
* Specialzed type testing stubs for certain non-instantiated types where we
can do [CidRange]-based subclass-checks for the class and
[CidRange]-based subtype-checks for the instantiated type arguments and
cid based comparisons for type parameters. (Note that this fast-case migth
result in some false-negatives!)
==> e.g. _HashMapEntry<K, V>, where we know [_HashMapEntry] is only
extended and not implemented.
This optimizes cases where the caller uses `new HashMap<A, B>()` and only
uses `A` and `B` as key/values (and not subclasses of it). The false-negative
can occur when subtypes of A or B are used. In such cases we fall back to the
[SubtypeTestCache]-based imlementation.
Reviewed-on: https://dart-review.googlesource.com/44788
Relands 25f98bcc75
[VM] Introduction of type testing stubs - Part 3
The changes include:
* Make AssertAssignableInstr no longer have a call-summary, which
helps methods with several parameter checks by not having to
re-load/re-initialize type arguments registers
* Lazily create SubtypeTestCaches: We already go to runtime to warm up
the caches, so we now also create the caches on the first runtime
call and patch the pool entries.
* No longer load the destination name into a register: We only need
the name when we throw an exception, so it is not on the hot path.
Instead we let the runtime look at the call site, decoding a pool
index from the instructions stream. The destination name will be
available in the pool, at a consecutive index to the subtype cache.
* Remove the fall-through to N=1 case for probing subtypeing tests,
since those will always be handled by the optimized stubs.
* Do not generate optimized stubs for FutureOr<T> (so far it just
falled-through to TTS). We can make optimzed version of that later,
but it requires special subtyping rules.
* Local code quality improvement in the type-testing-stubs: Avoid
extra jump at last case of cid-class-range checks.
There are still a number of optimization opportunities we can do in
future changes.
Reviewed-on: https://dart-review.googlesource.com/46984
Relands 2c52480ec8
[VM] Introduction of type testing stubs - Part 4
In order to avoid generating type testing stubs for too many types in
the system - and thereby potentially cause an increase in code size -
this change introduces a smarter way to decide for which types we should
generate optimized type testing stubs.
The precompiler creates a [TypeUsageInfo] which we use to collect
information. More specifically:
a) We collect the destination types for all type checks we emit
(we do this inside AssertAssignableInstr::EmitNativeCode).
-> These are types we might want to generate optimized type testing
stubs for.
b) We collect type argument vectors used in instance creations (we do
this inside AllocateObjectInstr::EmitNativeCode) and keep a set of
of used type argument vectors for each class.
After the precompiler has finished compiling normal code we scan the set
of destination types collected in a) for uninstantiated types (or more
specifically, type parameter types).
We then propagate the type argument vectors used on object allocation sites,
which were collected in b), in order to find out what kind of types are flowing
into those type parameters.
This allows us to extend the set of types which we test against, by
adding the types that flow into type parameters.
We use this final augmented set of destination types as a "filter" when
making the decision whether to generate an optimized type testing stub
for a given type.
Reviewed-on: https://dart-review.googlesource.com/48640
Issue https://github.com/dart-lang/sdk/issues/32603
Change-Id: I44a1d5d4b27454ae026aef2a301aada3dd399ea0
Reviewed-on: https://dart-review.googlesource.com/49861
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Ryan Macnak