[vm] Fix writing v8 snapshot profiles for core snapshots.

Fixes a crash when SetObjectTypeAndName is called twice for the
same object id with different types.

Don't add Code objects to the profile for non-Code carrying snapshots,
as references to the Code object are replaced with references to null.

TEST=vm/dart{_2}/v8_snapshot_profile_writer_test

Bug: https://github.com/dart-lang/sdk/issues/47463

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-nnbd-linux-release-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-nnbd-linux-debug-x64-try
Change-Id: Id9abf66509d422551ad5797744265eeb2c2ba2b5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/217643
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>

runtime/tests/vm/dart/v8_snapshot_profile_writer_test.dart

@@ -59,8 +59,9 @@ Snapshot testProfile(String profilePath) {
   return profile;
 }
 
-Future<void> testJIT(String dillPath) async {
-  final description = 'jit';
+Future<void> testJIT(String dillPath, String snapshotKind) async {
+  final includesCode = snapshotKind == 'core-jit';
+  final description = snapshotKind;
   Expect.isTrue(_seenDescriptions.add(description),
       "test configuration $description would be run multiple times");
 
@@ -73,9 +74,11 @@ Future<void> testJIT(String dillPath) async {
     final isolateDataPath = path.join(tempDir, 'isolate_data.bin');
 
     await run(genSnapshot, <String>[
-      '--snapshot-kind=core-jit',
-      '--vm_snapshot_instructions=$vmTextPath',
-      '--isolate_snapshot_instructions=$isolateTextPath',
+      '--snapshot-kind=$snapshotKind',
+      if (includesCode) ...<String>[
+        '--vm_snapshot_instructions=$vmTextPath',
+        '--isolate_snapshot_instructions=$isolateTextPath',
+      ],
       '--vm_snapshot_data=$vmDataPath',
       '--isolate_snapshot_data=$isolateDataPath',
       "--write-v8-snapshot-profile-to=$profilePath",
@@ -89,10 +92,12 @@ Future<void> testJIT(String dillPath) async {
     // Verify that the total size of the snapshot text and data sections is
     // the same as the sum of the shallow sizes of all objects in the profile.
     // This ensures that all bytes are accounted for in some way.
-    final actualSize = await File(vmTextPath).length() +
-        await File(isolateTextPath).length() +
-        await File(vmDataPath).length() +
-        await File(isolateDataPath).length();
+    int actualSize =
+        await File(vmDataPath).length() + await File(isolateDataPath).length();
+    if (includesCode) {
+      actualSize += await File(vmTextPath).length() +
+          await File(isolateTextPath).length();
+    }
     final expectedSize =
         profile.nodes.fold<int>(0, (size, n) => size + n.selfSize);
 
@@ -426,8 +431,10 @@ main() async {
     //   extra information that needs stripping), so no need to specify
     //   stripUtil for useAsm tests.
 
-    // Test profile generation with a core JIT snapshot.
-    await testJIT(jitDillPath);
+    // Test profile generation with a core snapshot (no code).
+    await testJIT(jitDillPath, 'core');
+    // Test profile generation with a core JIT snapshot (with code).
+    await testJIT(jitDillPath, 'core-jit');
 
     // Test unstripped ELF generation directly.
     await testAOT(aotDillPath);

runtime/tests/vm/dart_2/v8_snapshot_profile_writer_test.dart

@@ -61,8 +61,9 @@ Snapshot testProfile(String profilePath) {
   return profile;
 }
 
-Future<void> testJIT(String dillPath) async {
-  final description = 'jit';
+Future<void> testJIT(String dillPath, String snapshotKind) async {
+  final includesCode = snapshotKind == 'core-jit';
+  final description = snapshotKind;
   Expect.isTrue(_seenDescriptions.add(description),
       "test configuration $description would be run multiple times");
 
@@ -75,9 +76,11 @@ Future<void> testJIT(String dillPath) async {
     final isolateDataPath = path.join(tempDir, 'isolate_data.bin');
 
     await run(genSnapshot, <String>[
-      '--snapshot-kind=core-jit',
-      '--vm_snapshot_instructions=$vmTextPath',
-      '--isolate_snapshot_instructions=$isolateTextPath',
+      '--snapshot-kind=$snapshotKind',
+      if (includesCode) ...<String>[
+        '--vm_snapshot_instructions=$vmTextPath',
+        '--isolate_snapshot_instructions=$isolateTextPath',
+      ],
       '--vm_snapshot_data=$vmDataPath',
       '--isolate_snapshot_data=$isolateDataPath',
       "--write-v8-snapshot-profile-to=$profilePath",
@@ -91,10 +94,12 @@ Future<void> testJIT(String dillPath) async {
     // Verify that the total size of the snapshot text and data sections is
     // the same as the sum of the shallow sizes of all objects in the profile.
     // This ensures that all bytes are accounted for in some way.
-    final actualSize = await File(vmTextPath).length() +
-        await File(isolateTextPath).length() +
-        await File(vmDataPath).length() +
-        await File(isolateDataPath).length();
+    int actualSize =
+        await File(vmDataPath).length() + await File(isolateDataPath).length();
+    if (includesCode) {
+      actualSize += await File(vmTextPath).length() +
+          await File(isolateTextPath).length();
+    }
     final expectedSize =
         profile.nodes.fold<int>(0, (size, n) => size + n.selfSize);
 
@@ -420,8 +425,10 @@ main() async {
     //   extra information that needs stripping), so no need to specify
     //   stripUtil for useAsm tests.
 
-    // Test profile generation with a core JIT snapshot.
-    await testJIT(jitDillPath);
+    // Test profile generation with a core snapshot (no code).
+    await testJIT(jitDillPath, 'core');
+    // Test profile generation with a core JIT snapshot (with code).
+    await testJIT(jitDillPath, 'core-jit');
 
     // Test unstripped ELF generation directly.
     await testAOT(aotDillPath);

runtime/vm/app_snapshot.cc

@@ -5527,7 +5527,7 @@ class VMSerializationRoots : public SerializationRoots {
 
     if (!Snapshot::IncludesCode(s->kind())) {
       for (intptr_t i = 0; i < StubCode::NumEntries(); i++) {
-        s->AddBaseObject(StubCode::EntryAt(i).ptr(), "Code", "<stub code>");
+        s->AddBaseObject(StubCode::EntryAt(i).ptr());
       }
     }
   }

runtime/vm/v8_snapshot_writer.cc

@@ -42,7 +42,7 @@ void V8SnapshotProfileWriter::SetObjectTypeAndName(const ObjectId& object_id,
   const intptr_t type_index = node_types_.Add(type);
   if (info->type != kInvalidString && info->type != type_index) {
     FATAL("Attempting to assign mismatching type %s to node %s", type,
-          info->ToCString(nullptr, zone_));
+          info->ToCString(this, zone_));
   }
   info->type = type_index;
   // Don't overwrite any existing name.