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Martin Kustermann 407afe84ca [dart2wasm] Remove dynamic closure call vtable entry in most cases
This reduces acx main: module -0.35%,  global section: -2.3%

Previous change in [0] made dynamic call sites have per-caller-shape
dynamic forwarders.

In this change we utilize this: Since we know the dynamic caller shape
we can make the dynamic forwarder call via a closure representation that
matches this caller shape (modulo the type arguments - as a dynamic call
without type arguments may get default type arguments of unknown count).

=> This means we no longer have to pass types, positionals and named
   arguments as wasm arrays to dynamic call forwarder. Instead we can
   pass the arguments unpacked to the vtable.

Additionally we change `Function.apply`: If we know there's no
`Function.apply` usage with named arguments, we can enumerate all
possible closure representations and call the corresponding vtable
entry. We use 2 `br_table` instructions for this:

  * branch on number of type parameters
  * branch on number of positional parameters

Together these two changes means that neither dynamic forwarders nor
`Function.apply` will use the dynamic call entry.

=> We remove the dynamic call entry from the vtable construction

The only exception to the above are:

* If dynamic submodules is enabled we don't compute closed world
  information about closures and always call via dynamic call entry

* If `Function.apply` is used with named arguments then call via dynamic
  call entry (and make vtables have it).

[0] https://dart-review.googlesource.com/c/sdk/+/461720


Issue https://github.com/dart-lang/sdk/issues/60458

Change-Id: I26e6a2a48ee37616061d701dc4d4327c2e109e82
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/462060
Reviewed-by: Ömer Ağacan <omersa@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
2025-11-26 01:02:31 -08:00
..