[vm/compiler] Avoid speculative conversion in ffi Pointer.asTypedList

On 32-bit ARM in AOT mode Pointer.asTypedList is generated so that
there is a LoadField from Pointer.data_field which has kUnboxedFfiIntPtr
representation (uint32) and then the value is passed to a
StoreInstanceField for TypedDataBase.data_field which has kUnboxedIntPtr
representation (int32). As a result, a speculative uint32->int32
IntConverter instruction is inserted by SelectRepresentations pass.
AOT doesn't support deoptimization so code generation crashes after
retrying without speculative inlining.

This change fixes the type incompatibility by loading value with
LoadUntagged and then converting it with ConvertUntaggedToUnboxed(kUnboxedIntPtr).

TEST=ffi/regress_flutter97301_test
Fixes flutter/flutter#97301

Change-Id: I4a00d4ac7978b4775add0ddae510841a2b4cbae0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/230956
Reviewed-by: Daco Harkes <[email protected]>
Reviewed-by: Martin Kustermann <[email protected]>
Commit-Queue: Alexander Markov <[email protected]>

runtime/vm/compiler/frontend/kernel_to_il.cc

@@ -1582,7 +1582,8 @@ FlowGraph* FlowGraphBuilder::BuildGraphOfRecognizedMethod(
       // Initialize the result's data pointer field.
       body += LoadLocal(typed_data_object);
       body += LoadLocal(arg_pointer);
-      body += LoadNativeField(Slot::Pointer_data_field());
+      body += LoadUntagged(compiler::target::Pointer::data_field_offset());
+      body += ConvertUntaggedToUnboxed(kUnboxedIntPtr);
       body += StoreNativeField(Slot::TypedDataBase_data_field(),
                                StoreInstanceFieldInstr::Kind::kInitializing,
                                kNoStoreBarrier);

tests/ffi/regress_flutter97301_test.dart

@@ -0,0 +1,21 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+//
+// Verifies that there are no deoptimizing IntConverter instructions
+// used when converting Pointer to TypedData.
+// Regression test for https://github.com/flutter/flutter/issues/97301.
+
+import "dart:ffi";
+import "package:ffi/ffi.dart";
+
+@pragma("vm:never-inline")
+Pointer<Uint32> foo() => calloc(4);
+
+main() {
+  final Pointer<Uint32> offsetsPtr = foo();
+
+  for (var i = 0; i < 2; i++) {
+    print(offsetsPtr.asTypedList(1));
+  }
+}

tests/ffi_2/regress_flutter97301_test.dart

@@ -0,0 +1,23 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+//
+// Verifies that there are no deoptimizing IntConverter instructions
+// used when converting Pointer to TypedData.
+// Regression test for https://github.com/flutter/flutter/issues/97301.
+
+// @dart = 2.9
+
+import "dart:ffi";
+import "package:ffi/ffi.dart";
+
+@pragma("vm:never-inline")
+Pointer<Uint32> foo() => calloc(4);
+
+main() {
+  final Pointer<Uint32> offsetsPtr = foo();
+
+  for (var i = 0; i < 2; i++) {
+    print(offsetsPtr.asTypedList(1));
+  }
+}