commit 47357d853556df9f28436360e75409217fb4eff0
author Daco Harkes <dacoharkes@google.com> Wed Nov 22 16:13:42 2023 +0000
committer Daco Harkes <dacoharkes@google.com> Wed Nov 22 16:13:42 2023 +0000
tree 676d41b5b156c4643fe6d4561a5e6d6e75c47d98
parent 53eabe4824561a2294d09769858c1aabe9d6d9b5

Reland "[vm/ffi] Optimize @Native calls"

Original change in patchset 1.

The reland contains a fix for handles. The objects passed in handles
must live on the stack (or in the heap) so that that memory location
can be used as a handle.

This CL introduces a new allocation policy `RequiresRegister` which
forces constants to be spilled to the stack during register
allocation.
Note: Parameters to FfiCall instructions are currently not used in a
way that can make the parameters assigned to registers. So only
constants are treated currently. If we have a way to reproduce params
being assigned to registers, then we can force spilling for
non-consts as well in the register allocator.

Original change's description:
> [vm/ffi] Optimize `@Native` calls
>
> This CL removes static fields for storing the `@Native`'s function
> addresses. Instead, the function addresses are stored in the object
> pool for all archs except for ia32. ia32 has no AOT and no AppJit
> snapshots, so the addresses are directly embedded in the code.
>
> This CL removes the closure wrapping for `@Native`s. Instead of
> `pointer.asFunctionInternal()()` where `asFunction` returns a closure
> which contains the trampoline, the function is compiled to a body
> which contains the trampoline `Native()`. This is possible for
> `@Native`s because the dylib and symbol names are known statically.
>
> Doing the compilation in kernel_to_il instead of a CFE transform
> enables supporting static linking later. (The alternative would have
> been to transform in the cfe to a `@pragma('vm:cachable-idempotent')`
> instead of constructing the IL in kernel_to_il.
>
> To enable running resolution in ia32 in kernel_to_il.cc, the
> resolution function has been made available via
> `runtime/lib/ffi_dynamic_library.h`.
>
> Because the new calls are simply static calls, the TFA can figure
> out const arguments flowing to these calls. This leads to constant
> locations in the parameters to FfiCalls. So, this CL also introduces
> logic to move constants into `NativeLocation`s.

TEST=tests/ffi/vmspecific_ffi_native_handles_test.dart
TEST=tests/ffi/function_*_native_(leaf_)test.dart
TEST=pkg/vm/testcases/transformations/ffi/ffinative_compound_return.dart

Closes: https://github.com/dart-lang/sdk/issues/47625
CoreLibraryReviewExempt: Internal FFI implementation changes
Change-Id: Ia1401b335524dcbf50c663a8770d9a02802923df
Cq-Include-Trybots: luci.dart.try:vm-aot-android-release-arm64c-try,vm-aot-android-release-arm_x64-try,vm-aot-linux-debug-x64-try,vm-aot-linux-debug-x64c-try,vm-aot-mac-release-arm64-try,vm-aot-mac-release-x64-try,vm-aot-obfuscate-linux-release-x64-try,vm-aot-optimization-level-linux-release-x64-try,vm-aot-win-debug-arm64-try,vm-aot-win-debug-x64c-try,vm-aot-win-release-x64-try,vm-appjit-linux-debug-x64-try,vm-asan-linux-release-x64-try,vm-checked-mac-release-arm64-try,vm-eager-optimization-linux-release-ia32-try,vm-eager-optimization-linux-release-x64-try,vm-ffi-android-debug-arm-try,vm-ffi-android-debug-arm64c-try,vm-ffi-qemu-linux-release-arm-try,vm-ffi-qemu-linux-release-riscv64-try,vm-fuchsia-release-x64-try,vm-kernel-linux-debug-x64-try,vm-kernel-precomp-linux-release-x64-try,vm-linux-debug-ia32-try,vm-linux-debug-x64-try,vm-linux-debug-x64c-try,vm-mac-debug-arm64-try,vm-mac-debug-x64-try,vm-msan-linux-release-x64-try,vm-reload-linux-debug-x64-try,vm-reload-rollback-linux-debug-x64-try,vm-ubsan-linux-release-x64-try,vm-win-debug-arm64-try,vm-win-debug-x64-try,vm-win-debug-x64c-try,vm-win-release-ia32-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/333841
Reviewed-by: Slava Egorov <vegorov@google.com>