Revert "[vm] Defer object pools." and

"[vm] Defer object pool entries in instructions bare mode."

This reverts commit 0bf8d38b3d and
             commit 63d17b0ad8.

Reason for revert : Performance regression, please see https://github.com/flutter/flutter/issues/73794

TEST=(none it is a revert).

Change-Id: I828734f00c55d5095f632b154d7f4ab27a184baf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/181542
Commit-Queue: Siva Annamalai <asiva@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>

runtime/tests/vm/dart/split_literals.dart

@@ -1,21 +0,0 @@
-// Copyright (c) 2020, 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.
-
-import "split_literals_deferred.dart" deferred as lib;
-
-class Box {
-  final contents;
-  const Box(this.contents);
-  String toString() => "Box($contents)";
-}
-
-main() async {
-  print("Root literal!");
-  print(const <String>["Root literal in a list!"]);
-  print(const <String, String>{"key": "Root literal in a map!"});
-  print(const Box("Root literal in a box!"));
-
-  await lib.loadLibrary();
-  lib.foo();
-}

runtime/tests/vm/dart/split_literals_deferred.dart

@@ -1,12 +0,0 @@
-// Copyright (c) 2020, 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.
-
-import "split_literals.dart";
-
-void foo() {
-  print("Deferred literal!");
-  print(const <String>["Deferred literal in a list!"]);
-  print(const <String, String>{"key": "Deferred literal in a map!"});
-  print(const Box("Deferred literal in a box!"));
-}

runtime/tests/vm/dart/split_literals_test.dart

@@ -1,115 +0,0 @@
-// Copyright (c) 2020, 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.
-
-import "dart:convert";
-import "dart:io";
-
-import "package:expect/expect.dart";
-import "package:path/path.dart" as path;
-
-import "use_flag_test_helper.dart";
-
-main(List<String> args) async {
-  if (!isAOTRuntime) {
-    return; // Running in JIT: AOT binaries not available.
-  }
-
-  if (Platform.isAndroid) {
-    return; // SDK tree not available on the test device.
-  }
-
-  // These are the tools we need to be available to run on a given platform:
-  if (!File(platformDill).existsSync()) {
-    throw "Cannot run test as $platformDill does not exist";
-  }
-  if (!await testExecutable(genSnapshot)) {
-    throw "Cannot run test as $genSnapshot not available";
-  }
-
-  sanitizedPartitioning(manifest) {
-    // Filter core libraries, relativize URIs, and sort to make the results less
-    // sensitive to compiler or test harness changes.
-    print(manifest);
-    var units = <List<String>>[];
-    for (var unit in manifest['loadingUnits']) {
-      var uris = <String>[];
-      for (var uri in unit['libraries']) {
-        if (uri.startsWith("dart:")) continue;
-        uris.add(Uri.parse(uri).pathSegments.last);
-      }
-      uris.sort((a, b) => a.compareTo(b));
-      units.add(uris);
-    }
-    units.sort((a, b) => a.first.compareTo(b.first));
-    print(units);
-    return units;
-  }
-
-  await withTempDir("split-literals-test", (String tempDir) async {
-    final source =
-        path.join(sdkDir, "runtime/tests/vm/dart_2/split_literals.dart");
-    final dill = path.join(tempDir, "split_literals.dart.dill");
-    final snapshot = path.join(tempDir, "split_literals.so");
-    final manifest = path.join(tempDir, "split_literals.txt");
-    final deferredSnapshot = snapshot + "-2.part.so";
-
-    // Compile source to kernel.
-    await run(genKernel, <String>[
-      "--aot",
-      "--platform=$platformDill",
-      "-o",
-      dill,
-      source,
-    ]);
-
-    // Compile kernel to ELF.
-    await run(genSnapshot, <String>[
-      "--use_bare_instructions=false", //# object: ok
-      "--use_bare_instructions=true", //# bare: ok
-      "--snapshot-kind=app-aot-elf",
-      "--elf=$snapshot",
-      "--loading-unit-manifest=$manifest",
-      dill,
-    ]);
-    var manifestContent = jsonDecode(await new File(manifest).readAsString());
-    Expect.equals(2, manifestContent["loadingUnits"].length);
-    // Note package:expect doesn't do deep equals on collections.
-    Expect.equals(
-        "[[split_literals.dart],"
-        " [split_literals_deferred.dart]]",
-        sanitizedPartitioning(manifestContent).toString());
-    Expect.isTrue(await new File(deferredSnapshot).exists());
-
-    bool containsSubsequence(haystack, needle) {
-      outer:
-      for (var i = 0, n = haystack.length - needle.length; i < n; i++) {
-        for (var j = 0; j < needle.length; j++) {
-          if (haystack[i + j] != needle.codeUnitAt(j)) continue outer;
-        }
-        return true;
-      }
-      return false;
-    }
-
-    var unit_1 = await new File(snapshot).readAsBytes();
-    Expect.isTrue(containsSubsequence(unit_1, "Root literal!"));
-    Expect.isTrue(containsSubsequence(unit_1, "Root literal in a list!"));
-    Expect.isTrue(containsSubsequence(unit_1, "Root literal in a map!"));
-    Expect.isTrue(containsSubsequence(unit_1, "Root literal in a box!"));
-    Expect.isTrue(!containsSubsequence(unit_1, "Deferred literal!"));
-    Expect.isTrue(!containsSubsequence(unit_1, "Deferred literal in a list!"));
-    Expect.isTrue(!containsSubsequence(unit_1, "Deferred literal in a map!"));
-    Expect.isTrue(!containsSubsequence(unit_1, "Deferred literal in a box!"));
-
-    var unit_2 = await new File(deferredSnapshot).readAsBytes();
-    Expect.isTrue(!containsSubsequence(unit_2, "Root literal!"));
-    Expect.isTrue(!containsSubsequence(unit_2, "Root literal in a list!"));
-    Expect.isTrue(!containsSubsequence(unit_2, "Root literal in a map!"));
-    Expect.isTrue(!containsSubsequence(unit_2, "Root literal in a box!"));
-    Expect.isTrue(containsSubsequence(unit_2, "Deferred literal!"));
-    Expect.isTrue(containsSubsequence(unit_2, "Deferred literal in a list!"));
-    Expect.isTrue(containsSubsequence(unit_2, "Deferred literal in a map!"));
-    Expect.isTrue(containsSubsequence(unit_2, "Deferred literal in a box!"));
-  });
-}

runtime/tests/vm/dart_2/split_literals.dart

@@ -1,21 +0,0 @@
-// Copyright (c) 2020, 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.
-
-import "split_literals_deferred.dart" deferred as lib;
-
-class Box {
-  final contents;
-  const Box(this.contents);
-  String toString() => "Box($contents)";
-}
-
-main() async {
-  print("Root literal!");
-  print(const <String>["Root literal in a list!"]);
-  print(const <String, String>{"key": "Root literal in a map!"});
-  print(const Box("Root literal in a box!"));
-
-  await lib.loadLibrary();
-  lib.foo();
-}

runtime/tests/vm/dart_2/split_literals_deferred.dart

@@ -1,12 +0,0 @@
-// Copyright (c) 2020, 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.
-
-import "split_literals.dart";
-
-void foo() {
-  print("Deferred literal!");
-  print(const <String>["Deferred literal in a list!"]);
-  print(const <String, String>{"key": "Deferred literal in a map!"});
-  print(const Box("Deferred literal in a box!"));
-}

runtime/tests/vm/dart_2/split_literals_test.dart

@@ -1,115 +0,0 @@
-// Copyright (c) 2020, 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.
-
-import "dart:convert";
-import "dart:io";
-
-import "package:expect/expect.dart";
-import "package:path/path.dart" as path;
-
-import "use_flag_test_helper.dart";
-
-main(List<String> args) async {
-  if (!isAOTRuntime) {
-    return; // Running in JIT: AOT binaries not available.
-  }
-
-  if (Platform.isAndroid) {
-    return; // SDK tree not available on the test device.
-  }
-
-  // These are the tools we need to be available to run on a given platform:
-  if (!File(platformDill).existsSync()) {
-    throw "Cannot run test as $platformDill does not exist";
-  }
-  if (!await testExecutable(genSnapshot)) {
-    throw "Cannot run test as $genSnapshot not available";
-  }
-
-  sanitizedPartitioning(manifest) {
-    // Filter core libraries, relativize URIs, and sort to make the results less
-    // sensitive to compiler or test harness changes.
-    print(manifest);
-    var units = <List<String>>[];
-    for (var unit in manifest['loadingUnits']) {
-      var uris = <String>[];
-      for (var uri in unit['libraries']) {
-        if (uri.startsWith("dart:")) continue;
-        uris.add(Uri.parse(uri).pathSegments.last);
-      }
-      uris.sort((a, b) => a.compareTo(b));
-      units.add(uris);
-    }
-    units.sort((a, b) => a.first.compareTo(b.first));
-    print(units);
-    return units;
-  }
-
-  await withTempDir("split-literals-test", (String tempDir) async {
-    final source =
-        path.join(sdkDir, "runtime/tests/vm/dart_2/split_literals.dart");
-    final dill = path.join(tempDir, "split_literals.dart.dill");
-    final snapshot = path.join(tempDir, "split_literals.so");
-    final manifest = path.join(tempDir, "split_literals.txt");
-    final deferredSnapshot = snapshot + "-2.part.so";
-
-    // Compile source to kernel.
-    await run(genKernel, <String>[
-      "--aot",
-      "--platform=$platformDill",
-      "-o",
-      dill,
-      source,
-    ]);
-
-    // Compile kernel to ELF.
-    await run(genSnapshot, <String>[
-      "--use_bare_instructions=false", //# object: ok
-      "--use_bare_instructions=true", //# bare: ok
-      "--snapshot-kind=app-aot-elf",
-      "--elf=$snapshot",
-      "--loading-unit-manifest=$manifest",
-      dill,
-    ]);
-    var manifestContent = jsonDecode(await new File(manifest).readAsString());
-    Expect.equals(2, manifestContent["loadingUnits"].length);
-    // Note package:expect doesn't do deep equals on collections.
-    Expect.equals(
-        "[[split_literals.dart],"
-        " [split_literals_deferred.dart]]",
-        sanitizedPartitioning(manifestContent).toString());
-    Expect.isTrue(await new File(deferredSnapshot).exists());
-
-    bool containsSubsequence(haystack, needle) {
-      outer:
-      for (var i = 0, n = haystack.length - needle.length; i < n; i++) {
-        for (var j = 0; j < needle.length; j++) {
-          if (haystack[i + j] != needle.codeUnitAt(j)) continue outer;
-        }
-        return true;
-      }
-      return false;
-    }
-
-    var unit_1 = await new File(snapshot).readAsBytes();
-    Expect.isTrue(containsSubsequence(unit_1, "Root literal!"));
-    Expect.isTrue(containsSubsequence(unit_1, "Root literal in a list!"));
-    Expect.isTrue(containsSubsequence(unit_1, "Root literal in a map!"));
-    Expect.isTrue(containsSubsequence(unit_1, "Root literal in a box!"));
-    Expect.isTrue(!containsSubsequence(unit_1, "Deferred literal!"));
-    Expect.isTrue(!containsSubsequence(unit_1, "Deferred literal in a list!"));
-    Expect.isTrue(!containsSubsequence(unit_1, "Deferred literal in a map!"));
-    Expect.isTrue(!containsSubsequence(unit_1, "Deferred literal in a box!"));
-
-    var unit_2 = await new File(deferredSnapshot).readAsBytes();
-    Expect.isTrue(!containsSubsequence(unit_2, "Root literal!"));
-    Expect.isTrue(!containsSubsequence(unit_2, "Root literal in a list!"));
-    Expect.isTrue(!containsSubsequence(unit_2, "Root literal in a map!"));
-    Expect.isTrue(!containsSubsequence(unit_2, "Root literal in a box!"));
-    Expect.isTrue(containsSubsequence(unit_2, "Deferred literal!"));
-    Expect.isTrue(containsSubsequence(unit_2, "Deferred literal in a list!"));
-    Expect.isTrue(containsSubsequence(unit_2, "Deferred literal in a map!"));
-    Expect.isTrue(containsSubsequence(unit_2, "Deferred literal in a box!"));
-  });
-}

runtime/vm/clustered_snapshot.h

@@ -116,20 +116,16 @@ class DeserializationCluster : public ZoneAllocated {
 
   // Allocate memory for all objects in the cluster and write their addresses
   // into the ref array. Do not touch this memory.
-  virtual void ReadAlloc(Deserializer* deserializer, bool stamp_canonical) = 0;
+  virtual void ReadAlloc(Deserializer* deserializer, bool is_canonical) = 0;
 
   // Initialize the cluster's objects. Do not touch the memory of other objects.
-  virtual void ReadFill(Deserializer* deserializer, bool stamp_canonical) = 0;
+  virtual void ReadFill(Deserializer* deserializer, bool is_canonical) = 0;
 
   // Complete any action that requires the full graph to be deserialized, such
   // as rehashing.
   virtual void PostLoad(Deserializer* deserializer,
                         const Array& refs,
-                        bool canonicalize) {
-    if (canonicalize) {
-      FATAL1("%s needs canonicalization but doesn't define PostLoad", name());
-    }
-  }
+                        bool is_canonical) {}
 
   const char* name() const { return name_; }
 
@@ -351,7 +347,7 @@ class Serializer : public ThreadStackResource {
     Write<int32_t>(cid);
   }
 
-  void PrepareInstructions();
+  void PrepareInstructions(GrowableArray<CodePtr>* codes);
   void WriteInstructions(InstructionsPtr instr,
                          uint32_t unchecked_offset,
                          CodePtr code,
@@ -384,7 +380,6 @@ class Serializer : public ThreadStackResource {
   void set_loading_units(GrowableArray<LoadingUnitSerializationData*>* units) {
     loading_units_ = units;
   }
-  intptr_t current_loading_unit_id() { return current_loading_unit_id_; }
   void set_current_loading_unit_id(intptr_t id) {
     current_loading_unit_id_ = id;
   }
@@ -419,13 +414,6 @@ class Serializer : public ThreadStackResource {
     FATAL("Missing ref");
   }
 
-  bool HasRef(ObjectPtr object) const {
-    return heap_->GetObjectId(object) != kUnreachableReference;
-  }
-  bool IsWritten(ObjectPtr object) const {
-    return heap_->GetObjectId(object) > num_base_objects_;
-  }
-
  private:
   const char* ReadOnlyObjectType(intptr_t cid);
 
@@ -585,8 +573,6 @@ class Deserializer : public ThreadStackResource {
 
   uword ReadWordWith32BitReads() { return stream_.ReadWordWith32BitReads(); }
 
-  intptr_t position() const { return stream_.Position(); }
-  void set_position(intptr_t p) { stream_.SetPosition(p); }
   const uint8_t* CurrentBufferAddress() const {
     return stream_.AddressOfCurrentPosition();
   }

runtime/vm/compiler/relocation.cc

@@ -71,15 +71,8 @@ void CodeRelocator::Relocate(bool is_vm_isolate) {
   // We're guaranteed to have all calls resolved, since
   //   * backwards calls are resolved eagerly
   //   * forward calls are resolved once the target is written
-  if (!all_unresolved_calls_.IsEmpty()) {
-    for (auto call : all_unresolved_calls_) {
-      OS::PrintErr("Unresolved call to %s from %s\n",
-                   Object::Handle(call->callee).ToCString(),
-                   Object::Handle(call->caller).ToCString());
-    }
-  }
-  RELEASE_ASSERT(all_unresolved_calls_.IsEmpty());
-  RELEASE_ASSERT(unresolved_calls_by_destination_.IsEmpty());
+  ASSERT(all_unresolved_calls_.IsEmpty());
+  ASSERT(unresolved_calls_by_destination_.IsEmpty());
 
   // Any trampolines we created must be patched with the right offsets.
   auto it = trampolines_by_destination_.GetIterator();

runtime/vm/compiler/runtime_offsets_extracted.h

@@ -86,7 +86,7 @@ static constexpr dart::compiler::target::word Array_length_offset = 8;
 static constexpr dart::compiler::target::word Array_tags_offset = 0;
 static constexpr dart::compiler::target::word Array_type_arguments_offset = 4;
 static constexpr dart::compiler::target::word Class_declaration_type_offset =
-    48;
+    52;
 static constexpr dart::compiler::target::word Class_num_type_arguments_offset =
     88;
 static constexpr dart::compiler::target::word Class_super_type_offset = 44;
@@ -611,7 +611,7 @@ static constexpr dart::compiler::target::word Array_length_offset = 16;
 static constexpr dart::compiler::target::word Array_tags_offset = 0;
 static constexpr dart::compiler::target::word Array_type_arguments_offset = 8;
 static constexpr dart::compiler::target::word Class_declaration_type_offset =
-    96;
+    104;
 static constexpr dart::compiler::target::word Class_num_type_arguments_offset =
     164;
 static constexpr dart::compiler::target::word Class_super_type_offset = 88;
@@ -1140,7 +1140,7 @@ static constexpr dart::compiler::target::word Array_length_offset = 8;
 static constexpr dart::compiler::target::word Array_tags_offset = 0;
 static constexpr dart::compiler::target::word Array_type_arguments_offset = 4;
 static constexpr dart::compiler::target::word Class_declaration_type_offset =
-    48;
+    52;
 static constexpr dart::compiler::target::word Class_num_type_arguments_offset =
     88;
 static constexpr dart::compiler::target::word Class_super_type_offset = 44;
@@ -1662,7 +1662,7 @@ static constexpr dart::compiler::target::word Array_length_offset = 16;
 static constexpr dart::compiler::target::word Array_tags_offset = 0;
 static constexpr dart::compiler::target::word Array_type_arguments_offset = 8;
 static constexpr dart::compiler::target::word Class_declaration_type_offset =
-    96;
+    104;
 static constexpr dart::compiler::target::word Class_num_type_arguments_offset =
     164;
 static constexpr dart::compiler::target::word Class_super_type_offset = 88;
@@ -2194,7 +2194,7 @@ static constexpr dart::compiler::target::word Array_length_offset = 8;
 static constexpr dart::compiler::target::word Array_tags_offset = 0;
 static constexpr dart::compiler::target::word Array_type_arguments_offset = 4;
 static constexpr dart::compiler::target::word Class_declaration_type_offset =
-    48;
+    52;
 static constexpr dart::compiler::target::word Class_num_type_arguments_offset =
     88;
 static constexpr dart::compiler::target::word Class_super_type_offset = 44;
@@ -2713,7 +2713,7 @@ static constexpr dart::compiler::target::word Array_length_offset = 16;
 static constexpr dart::compiler::target::word Array_tags_offset = 0;
 static constexpr dart::compiler::target::word Array_type_arguments_offset = 8;
 static constexpr dart::compiler::target::word Class_declaration_type_offset =
-    96;
+    104;
 static constexpr dart::compiler::target::word Class_num_type_arguments_offset =
     164;
 static constexpr dart::compiler::target::word Class_super_type_offset = 88;
@@ -3236,7 +3236,7 @@ static constexpr dart::compiler::target::word Array_length_offset = 8;
 static constexpr dart::compiler::target::word Array_tags_offset = 0;
 static constexpr dart::compiler::target::word Array_type_arguments_offset = 4;
 static constexpr dart::compiler::target::word Class_declaration_type_offset =
-    48;
+    52;
 static constexpr dart::compiler::target::word Class_num_type_arguments_offset =
     88;
 static constexpr dart::compiler::target::word Class_super_type_offset = 44;
@@ -3752,7 +3752,7 @@ static constexpr dart::compiler::target::word Array_length_offset = 16;
 static constexpr dart::compiler::target::word Array_tags_offset = 0;
 static constexpr dart::compiler::target::word Array_type_arguments_offset = 8;
 static constexpr dart::compiler::target::word Class_declaration_type_offset =
-    96;
+    104;
 static constexpr dart::compiler::target::word Class_num_type_arguments_offset =
     164;
 static constexpr dart::compiler::target::word Class_super_type_offset = 88;
@@ -4280,7 +4280,7 @@ static constexpr dart::compiler::target::word AOT_Array_tags_offset = 0;
 static constexpr dart::compiler::target::word AOT_Array_type_arguments_offset =
     4;
 static constexpr dart::compiler::target::word
-    AOT_Class_declaration_type_offset = 48;
+    AOT_Class_declaration_type_offset = 52;
 static constexpr dart::compiler::target::word
     AOT_Class_num_type_arguments_offset = 88;
 static constexpr dart::compiler::target::word AOT_Class_super_type_offset = 44;
@@ -4864,7 +4864,7 @@ static constexpr dart::compiler::target::word AOT_Array_tags_offset = 0;
 static constexpr dart::compiler::target::word AOT_Array_type_arguments_offset =
     8;
 static constexpr dart::compiler::target::word
-    AOT_Class_declaration_type_offset = 96;
+    AOT_Class_declaration_type_offset = 104;
 static constexpr dart::compiler::target::word
     AOT_Class_num_type_arguments_offset = 164;
 static constexpr dart::compiler::target::word AOT_Class_super_type_offset = 88;
@@ -5454,7 +5454,7 @@ static constexpr dart::compiler::target::word AOT_Array_tags_offset = 0;
 static constexpr dart::compiler::target::word AOT_Array_type_arguments_offset =
     8;
 static constexpr dart::compiler::target::word
-    AOT_Class_declaration_type_offset = 96;
+    AOT_Class_declaration_type_offset = 104;
 static constexpr dart::compiler::target::word
     AOT_Class_num_type_arguments_offset = 164;
 static constexpr dart::compiler::target::word AOT_Class_super_type_offset = 88;
@@ -6043,7 +6043,7 @@ static constexpr dart::compiler::target::word AOT_Array_tags_offset = 0;
 static constexpr dart::compiler::target::word AOT_Array_type_arguments_offset =
     4;
 static constexpr dart::compiler::target::word
-    AOT_Class_declaration_type_offset = 48;
+    AOT_Class_declaration_type_offset = 52;
 static constexpr dart::compiler::target::word
     AOT_Class_num_type_arguments_offset = 88;
 static constexpr dart::compiler::target::word AOT_Class_super_type_offset = 44;
@@ -6620,7 +6620,7 @@ static constexpr dart::compiler::target::word AOT_Array_tags_offset = 0;
 static constexpr dart::compiler::target::word AOT_Array_type_arguments_offset =
     8;
 static constexpr dart::compiler::target::word
-    AOT_Class_declaration_type_offset = 96;
+    AOT_Class_declaration_type_offset = 104;
 static constexpr dart::compiler::target::word
     AOT_Class_num_type_arguments_offset = 164;
 static constexpr dart::compiler::target::word AOT_Class_super_type_offset = 88;
@@ -7203,7 +7203,7 @@ static constexpr dart::compiler::target::word AOT_Array_tags_offset = 0;
 static constexpr dart::compiler::target::word AOT_Array_type_arguments_offset =
     8;
 static constexpr dart::compiler::target::word
-    AOT_Class_declaration_type_offset = 96;
+    AOT_Class_declaration_type_offset = 104;
 static constexpr dart::compiler::target::word
     AOT_Class_num_type_arguments_offset = 164;
 static constexpr dart::compiler::target::word AOT_Class_super_type_offset = 88;

runtime/vm/compiler/type_testing_stubs_arm.cc

@@ -20,8 +20,16 @@ void TypeTestingStubGenerator::BuildOptimizedTypeTestStub(
     const Type& type,
     const Class& type_class) {
   BuildOptimizedTypeTestStubFastCases(assembler, hi, type, type_class);
-  __ Branch(compiler::Address(
-      THR, compiler::target::Thread::slow_type_test_entry_point_offset()));
+  if (!compiler::IsSameObject(
+          compiler::NullObject(),
+          compiler::CastHandle<Object>(slow_type_test_stub))) {
+    __ GenerateUnRelocatedPcRelativeTailCall();
+    unresolved_calls->Add(new compiler::UnresolvedPcRelativeCall(
+        __ CodeSize(), slow_type_test_stub, /*is_tail_call=*/true));
+  } else {
+    __ Branch(compiler::Address(
+        THR, compiler::target::Thread::slow_type_test_entry_point_offset()));
+  }
 }
 
 }  // namespace dart

runtime/vm/compiler/type_testing_stubs_arm64.cc

@@ -20,11 +20,19 @@ void TypeTestingStubGenerator::BuildOptimizedTypeTestStub(
     const Type& type,
     const Class& type_class) {
   BuildOptimizedTypeTestStubFastCases(assembler, hi, type, type_class);
-  __ ldr(
-      TMP,
-      compiler::Address(
-          THR, compiler::target::Thread::slow_type_test_entry_point_offset()));
-  __ br(TMP);
+  if (!compiler::IsSameObject(
+          compiler::NullObject(),
+          compiler::CastHandle<Object>(slow_type_test_stub))) {
+    __ GenerateUnRelocatedPcRelativeTailCall();
+    unresolved_calls->Add(new compiler::UnresolvedPcRelativeCall(
+        __ CodeSize(), slow_type_test_stub, /*is_tail_call=*/true));
+  } else {
+    __ ldr(TMP,
+           compiler::Address(
+               THR,
+               compiler::target::Thread::slow_type_test_entry_point_offset()));
+    __ br(TMP);
+  }
 }
 
 }  // namespace dart

runtime/vm/compiler/type_testing_stubs_x64.cc

@@ -20,8 +20,16 @@ void TypeTestingStubGenerator::BuildOptimizedTypeTestStub(
     const Type& type,
     const Class& type_class) {
   BuildOptimizedTypeTestStubFastCases(assembler, hi, type, type_class);
-  __ jmp(compiler::Address(
-      THR, compiler::target::Thread::slow_type_test_entry_point_offset()));
+  if (!compiler::IsSameObject(
+          compiler::NullObject(),
+          compiler::CastHandle<Object>(slow_type_test_stub))) {
+    __ GenerateUnRelocatedPcRelativeTailCall();
+    unresolved_calls->Add(new compiler::UnresolvedPcRelativeCall(
+        __ CodeSize(), slow_type_test_stub, /*is_tail_call=*/true));
+  } else {
+    __ jmp(compiler::Address(
+        THR, compiler::target::Thread::slow_type_test_entry_point_offset()));
+  }
 }
 
 }  // namespace dart

runtime/vm/object.cc

@@ -20212,11 +20212,9 @@ AbstractTypePtr Type::Canonicalize(Thread* thread, TrailPtr trail) const {
       }
     }
     ASSERT(this->Equals(type));
-    // TODO(rmacnak): Revisit immediately returning type after to changes to
-    // recanonicalization on load for literal splitting.
-    if (type.IsCanonical()) {
-      return type.ptr();
-    }
+    ASSERT(type.IsCanonical());
+    ASSERT(type.IsOld());
+    return type.ptr();
   }
 
   Type& type = Type::Handle(zone);

runtime/vm/program_visitor.cc

@@ -1371,15 +1371,9 @@ class AssignLoadingUnitsCodeVisitor : public CodeVisitor {
     MergeAssignment(obj_, id);
     obj_ = code.compressed_stackmaps();
     MergeAssignment(obj_, id);
-    if (!FLAG_use_bare_instructions) {
-      obj_ = code.object_pool();
-      MergeAssignment(obj_, id);
-    }
   }
 
   void MergeAssignment(const Object& obj, intptr_t id) {
-    if (obj.IsNull()) return;
-
     intptr_t old_id = heap_->GetLoadingUnit(obj_.ptr());
     if (old_id == WeakTable::kNoValue) {
       heap_->SetLoadingUnit(obj_.ptr(), id);

runtime/vm/raw_object.h

@@ -28,8 +28,8 @@
 //  * Target architecture
 //  * DART_PRECOMPILED_RUNTIME (i.e, AOT vs. JIT)
 //
-// That is, fields in UntaggedObject and its subclasses should only be included or
-// excluded conditionally based on these factors. Otherwise, the generated
+// That is, fields in UntaggedObject and its subclasses should only be included
+// or excluded conditionally based on these factors. Otherwise, the generated
 // offsets can be wrong (which should be caught by offset checking in dart.cc).
 //
 // TODO(dartbug.com/43646): Add DART_PRECOMPILER as another axis.
@@ -819,6 +819,8 @@ class UntaggedClass : public UntaggedObject {
   POINTER_FIELD(LibraryPtr, library)
   POINTER_FIELD(TypeArgumentsPtr, type_parameters)  // Array of TypeParameter.
   POINTER_FIELD(AbstractTypePtr, super_type)
+  POINTER_FIELD(ArrayPtr,
+                constants)  // Canonicalized const instances of this class.
   POINTER_FIELD(TypePtr, declaration_type)  // Declaration type for this class.
   POINTER_FIELD(ArrayPtr,
                 invocation_dispatcher_cache)  // Cache for dispatcher functions.
@@ -828,9 +830,7 @@ class UntaggedClass : public UntaggedObject {
                 direct_implementors)                        // Array of Class.
   POINTER_FIELD(GrowableObjectArrayPtr, direct_subclasses)  // Array of Class.
   POINTER_FIELD(ArrayPtr, dependent_code)  // CHA optimized codes.
-  POINTER_FIELD(ArrayPtr,
-                constants)  // Canonicalized const instances of this class.
-  VISIT_TO(ObjectPtr, constants)
+  VISIT_TO(ObjectPtr, dependent_code)
   ObjectPtr* to_snapshot(Snapshot::Kind kind) {
     switch (kind) {
       case Snapshot::kFullAOT:
@@ -1642,8 +1642,6 @@ class UntaggedObjectPool : public UntaggedObject {
 
   friend class Object;
   friend class CodeSerializationCluster;
-  friend class UnitSerializationRoots;
-  friend class UnitDeserializationRoots;
 };
 
 class UntaggedInstructions : public UntaggedObject {