TypeRef type wraps around another type and it was used to represent
a graph of recursive types. After [0], the only use of TypeRef is
for TypeParameter.bound which may indirectly reference the same
TypeParameter.
This change replaces TypeParameter.bound with TypeParameter.owner and
removes TypeRef entirely. Various parts of the VM no longer need to
handle and support TypeRefs.
TypeParameter.owner can reference a FunctionType, Class,
or, as an optimization, it can be set to null in order to share
class type parameters among different classes.
With the exception of the 'TypeParameter.owner' back pointer,
VM types are now not recursive and can be visited without
additional tracking.
Caveats:
* Generic FunctionType cannot be cloned in a shallow way:
when copying a FunctionType, type parameters should be cloned too
and their owners should be updated. For that reason,
a mapping between 'from' and 'to' function types
(FunctionTypeMapping) is maintained during type transformations
such as InstantiateFrom.
FunctionType::Clone is used instead of Object::Clone where
appropriate.
* When testing types for subtyping and equivalence, mapping
between function types is passed to make sure
type parameters belong to the equivalent function types.
* IL serializer needs to serialize function types as a whole before
serializing any types potentially pointing into the middle of a
function type (such as return type 'List<Y0>' pointing into
the middle of a function type 'List<Y0> Function<Y0>()').
[0] https://dart-review.googlesource.com/c/sdk/+/296300
TEST=ci
Change-Id: I67c2fd0117c6183a45e183919a7847fd1af70b3e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/294165
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
This is a reland of commit 135443706b
Original change's description:
> [vm] Avoid expanding/flattening type arguments vectors in Type objects
>
> Previously, vectors of type arguments were expanded to include type
> arguments corresponding to superclasses both in the instances of
> generic classes and in Type objects (after type finalization).
> As a result, Type objects after finalization could be recursive and
> need to use extra TypeRef objects to break loops. The finalization of
> types was very complex and sometimes slow.
>
> This change simplifies the representation of Type objects: now they
> always have short type argument vectors, corresponding only to
> the type parameters of their own classes (both before and after
> finalization). Vectors of type arguments in the instances of generic
> classes are still expanded/flattened.
>
> This greatly simplifies type finalization, makes Type objects
> non-recursive and removes the need to create and handle excessive
> TypeRefs for type arguments corresponding to superclasses,
> as those type arguments are no longer included into types.
> The only remaining use of TypeRefs is for bounds of type parameters.
>
> In order to expand/flatten type arguments, new methods Type::GetInstanceTypeArguments / Class::GetInstanceTypeArguments
> are introduced. They build canonical declaration type arguments
> once (for each class), and then instantiate them as needed.
>
> There are also simple helper methods to shrink type arguments (TypeArguments::FromInstanceTypeArguments) and expand type arguments without filling type arguments corresponding to superclasses (TypeArguments::ToInstantiatorTypeArguments).
>
> Time of edge case 'regress_51960_test' 15min -> 300ms.
>
> TEST=ci, runtime/tests/vm/dart/regress_51960_test.dart
>
> Fixes https://github.com/dart-lang/sdk/issues/52022
> Fixes https://github.com/dart-lang/sdk/issues/51960
>
> Change-Id: I75b466b74698a33c0bb5e1dcbd29542e413812a1
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/295060
> Reviewed-by: Ryan Macnak <rmacnak@google.com>
> Commit-Queue: Alexander Markov <alexmarkov@google.com>
TEST=runtime/tests/vm/dart/regress_b_278841863_test.dart
Fixes b/278841863.
Change-Id: Ib1e20055bfb26e1df0a077300c69f0bec7152480
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/296300
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
This reverts commit 135443706b.
Reason for revert: breaks many targets in G3, see b/278841863
Original change's description:
> [vm] Avoid expanding/flattening type arguments vectors in Type objects
>
> Previously, vectors of type arguments were expanded to include type
> arguments corresponding to superclasses both in the instances of
> generic classes and in Type objects (after type finalization).
> As a result, Type objects after finalization could be recursive and
> need to use extra TypeRef objects to break loops. The finalization of
> types was very complex and sometimes slow.
>
> This change simplifies the representation of Type objects: now they
> always have short type argument vectors, corresponding only to
> the type parameters of their own classes (both before and after
> finalization). Vectors of type arguments in the instances of generic
> classes are still expanded/flattened.
>
> This greatly simplifies type finalization, makes Type objects
> non-recursive and removes the need to create and handle excessive
> TypeRefs for type arguments corresponding to superclasses,
> as those type arguments are no longer included into types.
> The only remaining use of TypeRefs is for bounds of type parameters.
>
> In order to expand/flatten type arguments, new methods Type::GetInstanceTypeArguments / Class::GetInstanceTypeArguments
> are introduced. They build canonical declaration type arguments
> once (for each class), and then instantiate them as needed.
>
> There are also simple helper methods to shrink type arguments (TypeArguments::FromInstanceTypeArguments) and expand type arguments without filling type arguments corresponding to superclasses (TypeArguments::ToInstantiatorTypeArguments).
>
> Time of edge case 'regress_51960_test' 15min -> 300ms.
>
> TEST=ci, runtime/tests/vm/dart/regress_51960_test.dart
>
> Fixes https://github.com/dart-lang/sdk/issues/52022
> Fixes https://github.com/dart-lang/sdk/issues/51960
>
> Change-Id: I75b466b74698a33c0bb5e1dcbd29542e413812a1
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/295060
> Reviewed-by: Ryan Macnak <rmacnak@google.com>
> Commit-Queue: Alexander Markov <alexmarkov@google.com>
Change-Id: If0b2077305620593b8f03ebf6c135375c4086b1a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/296182
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Alexander Thomas <athom@google.com>
Commit-Queue: Ilya Yanok <yanok@google.com>
Previously, vectors of type arguments were expanded to include type
arguments corresponding to superclasses both in the instances of
generic classes and in Type objects (after type finalization).
As a result, Type objects after finalization could be recursive and
need to use extra TypeRef objects to break loops. The finalization of
types was very complex and sometimes slow.
This change simplifies the representation of Type objects: now they
always have short type argument vectors, corresponding only to
the type parameters of their own classes (both before and after
finalization). Vectors of type arguments in the instances of generic
classes are still expanded/flattened.
This greatly simplifies type finalization, makes Type objects
non-recursive and removes the need to create and handle excessive
TypeRefs for type arguments corresponding to superclasses,
as those type arguments are no longer included into types.
The only remaining use of TypeRefs is for bounds of type parameters.
In order to expand/flatten type arguments, new methods Type::GetInstanceTypeArguments / Class::GetInstanceTypeArguments
are introduced. They build canonical declaration type arguments
once (for each class), and then instantiate them as needed.
There are also simple helper methods to shrink type arguments (TypeArguments::FromInstanceTypeArguments) and expand type arguments without filling type arguments corresponding to superclasses (TypeArguments::ToInstantiatorTypeArguments).
Time of edge case 'regress_51960_test' 15min -> 300ms.
TEST=ci, runtime/tests/vm/dart/regress_51960_test.dart
Fixes https://github.com/dart-lang/sdk/issues/52022
Fixes https://github.com/dart-lang/sdk/issues/51960
Change-Id: I75b466b74698a33c0bb5e1dcbd29542e413812a1
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/295060
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Fixes#47190
TEST=None, only markdown files where edited.
Change-Id: Ife204f9c792b6bce30d0cd7bf2260ced11c8f2b4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/213049
Reviewed-by: Nicholas Shahan <nshahan@google.com>
Reviewed-by: Alexander Thomas <athom@google.com>
