[vm/ffi] Remove VM sizeOf runtime entry

After changing `elementAt` and `sizeOf` to only accept static types
(https://dart-review.googlesource.com/c/sdk/+/178200) and rewrite all
the calls with static types in the CFE
(https://dart-review.googlesource.com/c/sdk/+/182262), the runtime entry
can now be removed.

One less place where the runtime relies on `Struct` subtypes not being
tree shaken.
Issue: #38721

Because we're no longer using `NativeType`s in a RTE to calculate their
size, these do no longer need to be available in the precompiled
runtime.
Closes: #42809

TEST=tests/ffi(_2)/*

Change-Id: I8682a3bb4d2dc3ee71531cf71909e47489e96f12
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-nnbd-linux-debug-x64-try,vm-precomp-ffi-qemu-linux-release-arm-try,vm-ffi-android-debug-arm64-try,vm-ffi-android-debug-arm-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/185085
Commit-Queue: Daco Harkes <[email protected]>
Reviewed-by: Clement Skau <[email protected]>

Author: dcharkes

runtime/lib/ffi.cc

@@ -11,7 +11,6 @@
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/class_id.h"
-#include "vm/compiler/ffi/native_type.h"
 #include "vm/exceptions.h"
 #include "vm/flags.h"
 #include "vm/log.h"
@@ -30,45 +29,6 @@
 
 namespace dart {
 
-// The following functions are runtime checks on type arguments.
-// Some checks are also performed in kernel transformation, these are asserts.
-// Some checks are only performed at runtime to allow for generic code, these
-// throw ArgumentExceptions.
-
-static void CheckSized(const AbstractType& type_arg) {
-  const classid_t type_cid = type_arg.type_class_id();
-  if (IsFfiNativeTypeTypeClassId(type_cid) || IsFfiTypeVoidClassId(type_cid) ||
-      IsFfiTypeNativeFunctionClassId(type_cid)) {
-    const String& error = String::Handle(String::NewFormatted(
-        "%s does not have a predefined size (@unsized). "
-        "Unsized NativeTypes do not support [sizeOf] because their size "
-        "is unknown. "
-        "Consequently, [allocate], [Pointer.load], [Pointer.store], and "
-        "[Pointer.elementAt] are not available.",
-        String::Handle(type_arg.UserVisibleName()).ToCString()));
-    Exceptions::ThrowArgumentError(error);
-  }
-}
-
-// Calculate the size of a native type.
-//
-// You must check [IsConcreteNativeType] and [CheckSized] first to verify that
-// this type has a defined size.
-static size_t SizeOf(Zone* zone, const AbstractType& type) {
-  if (IsFfiTypeClassId(type.type_class_id())) {
-    return compiler::ffi::NativeType::FromAbstractType(zone, type)
-        .SizeInBytes();
-  } else {
-    Class& struct_class = Class::Handle(type.type_class());
-    Object& result = Object::Handle(
-        struct_class.InvokeGetter(Symbols::SizeOfStructField(),
-                                  /*throw_nsm_if_absent=*/false,
-                                  /*respect_reflectable=*/false));
-    ASSERT(!result.IsNull() && result.IsInteger());
-    return Integer::Cast(result).AsInt64Value();
-  }
-}
-
 // The remainder of this file implements the dart:ffi native methods.
 
 DEFINE_NATIVE_ENTRY(Ffi_fromAddress, 1, 1) {
@@ -101,13 +61,6 @@ DEFINE_NATIVE_ENTRY(Ffi_storePointer, 0, 3) {
   UNREACHABLE();
 }
 
-DEFINE_NATIVE_ENTRY(Ffi_sizeOf, 1, 0) {
-  GET_NATIVE_TYPE_ARGUMENT(type_arg, arguments->NativeTypeArgAt(0));
-  CheckSized(type_arg);
-
-  return Integer::New(SizeOf(zone, type_arg));
-}
-
 // Static invocations to this method are translated directly in streaming FGB.
 DEFINE_NATIVE_ENTRY(Ffi_asFunctionInternal, 2, 1) {
   UNREACHABLE();

runtime/vm/bootstrap_natives.h

@@ -405,7 +405,6 @@ namespace dart {
   V(Ffi_storePointer, 3)                                                       \
   V(Ffi_address, 1)                                                            \
   V(Ffi_fromAddress, 1)                                                        \
-  V(Ffi_sizeOf, 0)                                                             \
   V(Ffi_asFunctionInternal, 1)                                                 \
   V(Ffi_nativeCallbackFunction, 2)                                             \
   V(Ffi_pointerFromFunction, 1)                                                \

runtime/vm/compiler/compiler_sources.gni

@@ -107,6 +107,8 @@ compiler_sources = [
   "ffi/native_calling_convention.h",
   "ffi/native_location.cc",
   "ffi/native_location.h",
+  "ffi/native_type.cc",
+  "ffi/native_type.h",
   "ffi/recognized_method.cc",
   "ffi/recognized_method.h",
   "frontend/base_flow_graph_builder.cc",
@@ -189,8 +191,6 @@ compiler_api_sources = [
   "api/print_filter.cc",
   "api/print_filter.h",
   "api/type_check_mode.h",
-  "ffi/native_type.cc",
-  "ffi/native_type.h",
   "jit/compiler.cc",
   "jit/compiler.h",
   "runtime_api.cc",