dart-bytecode, arm64: +4.742% geomean
dart-bytecode-jit-unopt, arm64: +12.73% geomean
dart2js-compile, x64: +3.635% geomean
In the polymorphic and unlinked cases, call to a stub the does a linear scan against an ICData.
In the monomorphic case, call to a prologue of the expected target function that checks the expected receiver class. There is additional indirection in the JIT version compared to the AOT version to also tick a usage counter so the inliner can make good decisions.
In the megamorphic case, call to a stub that does a hash table lookup against a MegamorphicCache.
Megamorphic call sites face a loss of precision in usage counts. The call site count is not recorded and the usage counter of the target function is used as an approximation.
Monomorphic and megamorphic calls sites are reset to the polymorphic/unlinked state on hot reload.
Monomorphic and megamorphic calls sites do not check the stepping state, so they are reset to the polymorphic/unlinked state when stepping begins and disabled.
Back-edges now increment the usage counter in addition to checking it. This ensures function with loops containing monomorphic calls will eventually cross the optimization threshold.
Fixed backwards use of kMonomorphicEntryOffset and kPolymorphicEntryOffset.
Fixed C stack overflow when bouncing between the KBC interpreter and a simulator.
Bug: https://github.com/dart-lang/sdk/issues/26780
Bug: https://github.com/dart-lang/sdk/issues/36409
Bug: https://github.com/dart-lang/sdk/issues/36731
Change-Id: I78a49cccd962703a459288e71ce246ed845df474
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/102820
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Refactoring motivation: go/dart-simulated-ffi
* template Location and PairLocation with <dart::Register, dart::FpuRegister> or <dart::host::Register, dart::host::FpuRegister>
* move RegisterName and FpuRegisterName from assembler to constants
* move methods that are only implemented by Location and not HostLocation out of Location
Change-Id: Ie9aa2dae63380da0cbfb15eacc440537fbed48f8
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-bare-linux-release-simarm-try, vm-kernel-precomp-bare-linux-release-simarm64-try, vm-kernel-precomp-linux-debug-x64-try, vm-kernel-linux-debug-simdbc64-try, vm-kernel-precomp-win-release-simarm64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98845
Commit-Queue: Daco Harkes <dacoharkes@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Auto-Submit: Daco Harkes <dacoharkes@google.com>
This is a reland of 49c94d3600
It appears that the major regressions were introduced not by the typed data unification
changes but rather by 3fd124db1f "[vm] Repair the resolver abstraction." which got
reverted in e979895efb "Revert "[vm] Repair the resolver abstraction."
Original change's description:
> Temporary revert of two changes which potentially caused performance regressions in Flutter.
>
> Revert "[vm] Re-number class ids for internal/external typed data and typed data views"
>
> This reverts commit a062221b76.
>
> Revert "[vm] Unify internal/external/view typed data into new RawTypedDataBase class"
>
> This reverts commit 94362f1af0.
>
> Change-Id: I7189c976aa86cdcf0a3802631bff754baf3ca2cc
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98521
> Reviewed-by: Ben Konyi <bkonyi@google.com>
Change-Id: I758775ccc426a02bce538d07ea04d9c67e8933d2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98562
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
Auto-Submit: Martin Kustermann <kustermann@google.com>
This reverts commit 49c94d3600.
Reason for revert: Relanding
Original change's description:
> Temporary revert of two changes which potentially caused performance regressions in Flutter.
>
> Revert "[vm] Re-number class ids for internal/external typed data and typed data views"
>
> This reverts commit a062221b76.
>
> Revert "[vm] Unify internal/external/view typed data into new RawTypedDataBase class"
>
> This reverts commit 94362f1af0.
>
> Change-Id: I7189c976aa86cdcf0a3802631bff754baf3ca2cc
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98521
> Reviewed-by: Ben Konyi <bkonyi@google.com>
TBR=bkonyi@google.com,asiva@google.com
Change-Id: I5c5be67fcec05434283153cb2592ba41afd1f41f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98505
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Ben Konyi <bkonyi@google.com>
Revert "[vm] Re-number class ids for internal/external typed data and typed data views"
This reverts commit a062221b76.
Revert "[vm] Unify internal/external/view typed data into new RawTypedDataBase class"
This reverts commit 94362f1af0.
Change-Id: I7189c976aa86cdcf0a3802631bff754baf3ca2cc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98521
Reviewed-by: Ben Konyi <bkonyi@google.com>
This moves the length field as well as an inner pointer to the start of
the data into the RawTypedDataBase class. The inner pointer is updated
on allocation, scavenges and old space compactions.
To avoid writing more assembly the typed data view factory constructors
will be generated using IL, which will update the inner pointer. This
required adding new IR instructions and changing the existing
UnboxedIntConverter instruction.
This is the foundation work to de-virtualize calls on the public typed
data types, e.g. Uint8List.
Issue https://github.com/dart-lang/sdk/issues/35154
Cq-Include-Trybots: luci.dart.try:vm-canary-linux-debug-try, vm-dartkb-linux-debug-x64-try, vm-dartkb-linux-release-x64-try, vm-kernel-asan-linux-release-x64-try, vm-kernel-checked-linux-release-x64-try, vm-kernel-linux-debug-ia32-try, vm-kernel-linux-debug-simdbc64-try, vm-kernel-linux-debug-x64-try, vm-kernel-linux-product-x64-try, vm-kernel-linux-release-ia32-try, vm-kernel-linux-release-simarm-try, vm-kernel-linux-release-simarm64-try, vm-kernel-linux-release-simdbc64-try, vm-kernel-linux-release-x64-try, vm-kernel-optcounter-threshold-linux-release-ia32-try, vm-kernel-optcounter-threshold-linux-release-x64-try, vm-kernel-precomp-android-release-arm-try, vm-kernel-precomp-bare-linux-release-simarm-try, vm-kernel-precomp-bare-linux-release-simarm64-try, vm-kernel-precomp-bare-linux-release-x64-try, vm-kernel-precomp-linux-debug-x64-try, vm-kernel-precomp-linux-product-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-obfuscate-linux-release-x64-try, vm-kernel-precomp-win-release-simarm64-try, vm-kernel-precomp-win-release-x64-try, vm-kernel-reload-linux-debug-x64-try, vm-kernel-reload-linux-release-x64-try, vm-kernel-reload-rollback-linux-debug-x64-try, vm-kernel-reload-rollback-linux-release-x64-try, vm-kernel-win-debug-ia32-try, vm-kernel-win-debug-x64-try, vm-kernel-win-product-x64-try, vm-kernel-win-release-ia32-try, vm-kernel-win-release-x64-try
Change-Id: I1aab0dd93fa0f06a05299ab4cb019cf898b9e1ef
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/97960
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Prototype for `dart:ffi` on Linux/MacOS x64 in JIT mode.
`dart:ffi` is experimental and its API is likely to change in the future.
Progress and design decisions are tracked in https://github.com/dart-lang/sdk/projects/13
issue: https://github.com/dart-lang/sdk/issues/34452
Change-Id: Ifa4566388e42c8757f154741d11e303465ef305d
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-mac-release-simarm64-try, vm-kernel-precomp-win-release-x64-try, vm-kernel-mac-debug-x64-try, vm-kernel-asan-linux-release-x64
Reviewed-on: https://dart-review.googlesource.com/c/80124
Reviewed-by: Samir Jindel <sjindel@google.com>
Auto-Submit: Daco Harkes <dacoharkes@google.com>
This is the next step towards preventing compiler from directly peeking
into runtime and instead interact with runtime through a well defined
surface. The goal of the refactoring to locate all places where compiler
accesses some runtime information and partion those accesses into two
categories:
- creating objects in the host runtime (e.g. allocating strings, numbers, etc)
during compilation;
- accessing properties of the target runtime (e.g. offsets of fields) to
embed those into the generated code;
This change introduces dart::compiler and dart::compiler::target namespaces.
All code in the compiler will gradually be moved into dart::compiler namespace.
One of the motivations for this change is to be able to prevent access to
globally defined host constants like kWordSize by shadowing them in the
dart::compiler namespace.
The nested namespace dart::compiler::target hosts all information about
target runtime that compiler could access, e.g. compiler::target::kWordSize
defines word size of the target which will eventually be made different
from the host kWordSize (defined by dart::kWordSize).
The API for compiler to runtime interaction is placed into compiler_api.h.
Note that we still permit runtime to access compiler internals directly -
this is not going to be decoupled as part of this work.
Issue https://github.com/dart-lang/sdk/issues/31709
Change-Id: If4396d295879391becfa6c38d4802bbff81f5b20
Reviewed-on: https://dart-review.googlesource.com/c/90242
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
ARM write barrier goes from
ldrne lr, [thr, #+508]
blxne lr
to
blne <offset>
ARM64 write barrier goes from (similarly X64)
beq +8
ldrx lr, [thr, #1056]
blr lr
to
beq +4
bl <offset>
It reduces RX on arm/arm64 by around 0.9%
Though the write barrier wrappers stub has multiple entrypoints (one for
each available register). Because of this, we modify the relocation
logic to support per-call offsets into the target.
To avoid making the assembler code depend on StubCode/FlowGraphCompiler,
we set a closure, which the assembler can call.
Issue https://github.com/dart-lang/sdk/issues/33274
Change-Id: I9e3d68260cab7ef19ea88f1235c78d6031819d6d
Reviewed-on: https://dart-review.googlesource.com/c/90063
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
This is a reland of 6ba3e55ecc
The issue was that SlowTypeTestStub used in precompiled mode did not handle a
Smi instance before calling the Subtype2TestCache stub which does not support
it. See PatchSet 2 for the fix.
Is there a more efficient solution?
Original change's description:
> [VM runtime] Support Smi instances in type test cache.
>
> This adds SubtypeTestCache-based optimizations for type tests against
> * dst_type = FutureOr<T> (when T=int/num)
> * dst_type = T (when T = FutureOr<int/num>)
>
> Remove dangerous LoadClass pseudo assembler instruction (does not work for Smi).
> Handle instantiated void in type tests (along with dynamic and Object).
>
> Change-Id: I0df0fc72ff173b9464d16cc971969132b055a429
> Reviewed-on: https://dart-review.googlesource.com/c/81182
> Commit-Queue: Régis Crelier <regis@google.com>
> Reviewed-by: Martin Kustermann <kustermann@google.com>
Change-Id: I333ca47aebd7f0b663059ab6afc5d1cd8d7d5210
Reviewed-on: https://dart-review.googlesource.com/c/81320
Commit-Queue: Régis Crelier <regis@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
This adds SubtypeTestCache-based optimizations for type tests against
* dst_type = FutureOr<T> (when T=int/num)
* dst_type = T (when T = FutureOr<int/num>)
Remove dangerous LoadClass pseudo assembler instruction (does not work for Smi).
Handle instantiated void in type tests (along with dynamic and Object).
Change-Id: I0df0fc72ff173b9464d16cc971969132b055a429
Reviewed-on: https://dart-review.googlesource.com/c/81182
Commit-Queue: Régis Crelier <regis@google.com>
Reviewed-by: Martin Kustermann <kustermann@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>
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>
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