Check that Dart_CreateIsolate is given a correct kind of snapshot.

R=zra@google.com

Review URL: https://codereview.chromium.org/2481013006 .

runtime/include/dart_api.h

@@ -854,7 +854,9 @@ DART_EXPORT bool Dart_IsVMFlagSet(const char* flag_name);
  *
  * A snapshot can be used to restore the VM quickly to a saved state
  * and is useful for fast startup. If snapshot data is provided, the
- * isolate will be started using that snapshot data.
+ * isolate will be started using that snapshot data. Requires a core snapshot or
+ * an app snapshot created by Dart_CreateSnapshot or
+ * Dart_CreatePrecompiledSnapshot* from a VM with the same version.
  *
  * Requires there to be no current isolate.
  *
@@ -2795,7 +2797,9 @@ DART_EXPORT Dart_Handle Dart_LoadScript(Dart_Handle url,
                                         intptr_t col_offset);
 
 /**
- * Loads the root script for current isolate from a snapshot.
+ * Loads the root script for current isolate from a script snapshot. The
+ * snapshot must have been created by Dart_CreateScriptSnapshot from a VM with
+ * the same version.
  *
  * \param buffer A buffer which contains a snapshot of the script.
  * \param buffer_len Length of the passed in buffer.

runtime/vm/dart.cc

@@ -522,8 +522,14 @@ RawError* Dart::InitializeIsolate(const uint8_t* snapshot_buffer, void* data) {
       const String& message = String::Handle(String::New("Invalid snapshot"));
       return ApiError::New(message);
     }
+    if (snapshot->kind() != snapshot_kind_) {
+      const String& message = String::Handle(
+          String::NewFormatted("Invalid snapshot kind: got '%s', expected '%s'",
+                               Snapshot::KindToCString(snapshot->kind()),
+                               Snapshot::KindToCString(snapshot_kind_)));
+      return ApiError::New(message);
+    }
     ASSERT(Snapshot::IsFull(snapshot->kind()));
-    ASSERT(snapshot->kind() == snapshot_kind_);
     if (FLAG_trace_isolates) {
       OS::Print("Size of isolate snapshot = %" Pd "\n", snapshot->length());
     }

runtime/vm/snapshot.cc

@@ -142,6 +142,21 @@ static intptr_t GetTypeIndex(ObjectStore* object_store,
 }
 
 
+const char* Snapshot::KindToCString(Kind kind) {
+  switch (kind) {
+    case kCore: return "core";
+    case kScript: return "script";
+    case kMessage: return "message";
+    case kAppWithJIT: return "app-jit";
+    case kAppNoJIT: return "app-aot";
+    case kNone: return "none";
+    case kInvalid:
+    default:
+      return "invalid";
+  }
+}
+
+
 // TODO(5411462): Temporary setup of snapshot for testing purposes,
 // the actual creation of a snapshot maybe done differently.
 const Snapshot* Snapshot::SetupFromBuffer(const void* raw_memory) {

runtime/vm/snapshot.h

@@ -165,6 +165,7 @@ class Snapshot {
     kNone,        // dart_bootstrap/gen_snapshot
     kInvalid
   };
+  static const char* KindToCString(Kind kind);
 
   static const int kHeaderSize = 2 * sizeof(int64_t);
   static const int kLengthIndex = 0;

runtime/vm/snapshot_test.cc

@@ -1634,6 +1634,89 @@ UNIT_TEST_CASE(ScriptSnapshot2) {
 }
 
 
+UNIT_TEST_CASE(MismatchedSnapshotKinds) {
+  const char* kScriptChars =
+      "main() { print('Hello, world!'); }";
+  Dart_Handle result;
+
+  uint8_t* buffer;
+  intptr_t size;
+  intptr_t vm_isolate_snapshot_size;
+  uint8_t* isolate_snapshot = NULL;
+  intptr_t isolate_snapshot_size;
+  uint8_t* full_snapshot = NULL;
+  uint8_t* script_snapshot = NULL;
+
+  bool saved_load_deferred_eagerly_mode = FLAG_load_deferred_eagerly;
+  FLAG_load_deferred_eagerly = true;
+  bool saved_concurrent_sweep_mode = FLAG_concurrent_sweep;
+  FLAG_concurrent_sweep = false;
+  {
+    // Start an Isolate, and create a full snapshot of it.
+    TestIsolateScope __test_isolate__;
+    Dart_EnterScope();  // Start a Dart API scope for invoking API functions.
+
+    // Write out the script snapshot.
+    result = Dart_CreateSnapshot(NULL,
+                                 &vm_isolate_snapshot_size,
+                                 &isolate_snapshot,
+                                 &isolate_snapshot_size);
+    EXPECT_VALID(result);
+    full_snapshot = reinterpret_cast<uint8_t*>(malloc(isolate_snapshot_size));
+    memmove(full_snapshot, isolate_snapshot, isolate_snapshot_size);
+    Dart_ExitScope();
+  }
+  FLAG_concurrent_sweep = saved_concurrent_sweep_mode;
+  FLAG_load_deferred_eagerly = saved_load_deferred_eagerly_mode;
+
+  {
+    // Create an Isolate using the full snapshot, load a script and create
+    // a script snapshot of the script.
+    TestCase::CreateTestIsolateFromSnapshot(full_snapshot);
+    Dart_EnterScope();  // Start a Dart API scope for invoking API functions.
+
+    // Create a test library and Load up a test script in it.
+    TestCase::LoadTestScript(kScriptChars, NULL);
+
+    EXPECT_VALID(Api::CheckAndFinalizePendingClasses(Thread::Current()));
+
+    // Write out the script snapshot.
+    result = Dart_CreateScriptSnapshot(&buffer, &size);
+    EXPECT_VALID(result);
+    script_snapshot = reinterpret_cast<uint8_t*>(malloc(size));
+    memmove(script_snapshot, buffer, size);
+    Dart_ExitScope();
+    Dart_ShutdownIsolate();
+  }
+
+  {
+    // Use a script snapshot where a full snapshot is expected.
+    char* error = NULL;
+    Dart_Isolate isolate = Dart_CreateIsolate("script-uri", "main",
+                                              script_snapshot, NULL, NULL,
+                                              &error);
+    EXPECT(isolate == NULL);
+    EXPECT(error != NULL);
+    EXPECT_SUBSTRING("got 'script', expected 'core'", error);
+  }
+
+  {
+    TestCase::CreateTestIsolateFromSnapshot(full_snapshot);
+    Dart_EnterScope();  // Start a Dart API scope for invoking API functions.
+
+    // Use a full snapshot where a script snapshot is expected.
+    Dart_Handle result = Dart_LoadScriptFromSnapshot(full_snapshot, size);
+    EXPECT_ERROR(result, "Dart_LoadScriptFromSnapshot expects parameter"
+                         " 'buffer' to be a script type snapshot.");
+
+    Dart_ExitScope();
+  }
+  Dart_ShutdownIsolate();
+  free(full_snapshot);
+  free(script_snapshot);
+}
+
+
 #endif  // !PRODUCT