Make it possible for arrays to have default-implemented methods by MichalStrehovsky · Pull Request #96672 · dotnet/runtime

MichalStrehovsky · 2024-01-09T12:10:28Z

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

ghost · 2024-01-09T12:10:32Z

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Author:	MichalStrehovsky
Assignees:	-
Labels:	`area-NativeAOT-coreclr`
Milestone:	-

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

Noticed this while working on #96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in #96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

…et#96672) Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

MichalStrehovsky · 2024-01-09T12:10:28Z

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

ghost · 2024-01-09T12:10:32Z

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Author:	MichalStrehovsky
Assignees:	-
Labels:	`area-NativeAOT-coreclr`
Milestone:	-

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

Noticed this while working on #96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in #96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

…et#96672) Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

MichalStrehovsky · 2024-01-09T12:10:28Z

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

ghost · 2024-01-09T12:10:32Z

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Author:	MichalStrehovsky
Assignees:	-
Labels:	`area-NativeAOT-coreclr`
Milestone:	-

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

Noticed this while working on #96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in #96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

…et#96672) Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

MichalStrehovsky · 2024-01-09T12:10:28Z

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

ghost · 2024-01-09T12:10:32Z

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Author:	MichalStrehovsky
Assignees:	-
Labels:	`area-NativeAOT-coreclr`
Milestone:	-

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

Noticed this while working on #96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in #96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

…et#96672) Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

MichalStrehovsky · 2024-01-09T12:10:28Z

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

ghost · 2024-01-09T12:10:32Z

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Author:	MichalStrehovsky
Assignees:	-
Labels:	`area-NativeAOT-coreclr`
Milestone:	-

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

Noticed this while working on #96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in #96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

…et#96672) Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

MichalStrehovsky · 2024-01-09T12:10:28Z

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

ghost · 2024-01-09T12:10:32Z

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Author:	MichalStrehovsky
Assignees:	-
Labels:	`area-NativeAOT-coreclr`
Milestone:	-

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

Noticed this while working on #96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in #96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

…et#96672) Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

MichalStrehovsky · 2024-01-09T12:10:28Z

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

ghost · 2024-01-09T12:10:32Z

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Author:	MichalStrehovsky
Assignees:	-
Labels:	`area-NativeAOT-coreclr`
Milestone:	-

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

Noticed this while working on #96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in #96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

…et#96672) Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

MichalStrehovsky · 2024-01-09T12:10:28Z

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

ghost · 2024-01-09T12:10:32Z

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the Array<T> type from corelib (that has the methods).

The GetClosestDefType API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods.

In #95830, arrays are going to get a default interface method (the implementation of IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item which is virtual final but still a new slot).

@dotnet/ilc-contrib

Author:	MichalStrehovsky
Assignees:	-
Labels:	`area-NativeAOT-coreclr`
Milestone:	-

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

Noticed this while working on #96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in #96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

…et#96672) Within the managed type system, the array types are special. When asking question about virtual/interface methods implemented by arrays, one needs to switch from the array type (that doesn't have any virtual methods as far as the type system in concerned) to the `Array<T>` type from corelib (that has the methods). The `GetClosestDefType` API is the API that does this transformation. We were not consistent enough in using it and it didn't work for default methods. In dotnet#95830, arrays are going to get a default interface method (the implementation of `IList<T>.System.Collections.Generic.IReadOnlyList<T>.get_Item` which is `virtual final` but still a new slot).

Noticed this while working on dotnet#96672. There are two ways how virtual method can be referred to: as a direct reference to the method body (i.e. non-virtually), or as a reference to a particular slot number (virtually). When we mark a virtual method as visible by reflection, it typically means “virtually visible to reflection” (one can invoke the method with a random derived `this` so the invoke happens through the slot). But we still try to optimize this into a direct reference if possible so that we don’t waste an extra slot. This is possible for final methods, or methods on sealed classes for example. The marking in dependency graph didn’t take into account this optimization – it was creating an unnecessary virtual slot for reflection-visible final methods that then went unused. With this half of the diff in dotnet#96672 is technically not necessary (we no longer end up with the new virtual method in the vtable), but that fix is still a correct fix.

MichalStrehovsky added the area-NativeAOT-coreclr label Jan 9, 2024

ghost assigned MichalStrehovsky Jan 9, 2024

MichalStrehovsky mentioned this pull request Jan 9, 2024
Make mutable generic collection interfaces implement read-only collection interfaces #95830
Merged

jkotas approved these changes Jan 9, 2024
View reviewed changes

build-analysisBot mentioned this pull request Jan 9, 2024
Checkout failure: "Git fetch failed with exit code 128" dotnet/arcade#9009
Open
2 tasks

TylerBrinkley added a commit to TylerBrinkley/runtime that referenced this pull request Jan 9, 2024
Incorporatedotnet#96672
0580aae

MichalStrehovsky merged commit 3710d53 into dotnet:mainJan 9, 2024

MichalStrehovsky deleted the defaultsonarrays branch January 9, 2024 19:56

MichalStrehovsky mentioned this pull request Jan 10, 2024
Do not generate reflectable sealed methods as virtual #96738
Merged

github-actionsBot locked and limited conversation to collaborators Feb 9, 2024