Teach gen_snapshot how to create script snapshots if given a core snapshot to create them against.

runtime/bin/gen_snapshot.cc

 // Copyright (c) 2013, 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.
 
 // Generate a snapshot file after loading all the scripts specified on the
 // command line.
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 24 matching lines @@
 // Exit code indicating a compilation error.
 static const int kCompilationErrorExitCode = 254;
 // Exit code indicating an unhandled error that is not a compilation error.
 static const int kErrorExitCode = 255;
 // Exit code indicating a vm restart request.  Never returned to the user.
 static const int kRestartRequestExitCode = 1000;
 
 #define CHECK_RESULT(result)                                                   \
   if (Dart_IsError(result)) {                                                  \
     intptr_t exit_code = 0;                                                    \
-    Log::PrintErr("Error: %s", Dart_GetError(result));                         \
+    Log::PrintErr("Error: %s\n", Dart_GetError(result));                       \
     if (Dart_IsCompilationError(result)) {                                     \
       exit_code = kCompilationErrorExitCode;                                   \
     } else if (Dart_IsApiError(result)) {                                      \
       exit_code = kApiErrorExitCode;                                           \
     } else if (Dart_IsVMRestartRequest(result)) {                              \
       exit_code = kRestartRequestExitCode;                                     \
     } else {                                                                   \
       exit_code = kErrorExitCode;                                              \
     }                                                                          \
     Dart_ExitScope();                                                          \
     Dart_ShutdownIsolate();                                                    \
     exit(exit_code);                                                           \
   }
 
 
+// The core snapshot to use when creating isolates. Normally NULL, but loaded
+// from a file when creating script snapshots.
+const uint8_t* isolate_snapshot_data = NULL;
+
+
 // Global state that indicates whether a snapshot is to be created and
 // if so which file to write the snapshot into.
+enum SnapshotKind {
+  kNone,
+  kCore,
+  kScript,
+  kAppAOTBlobs,
+  kAppAOTAssembly,
+};

[siva, 2017/02/14 03:56:09]

why not move this to snapshot_utils.h and share it with main?

+static SnapshotKind snapshot_kind = kNone;
 static const char* vm_snapshot_data_filename = NULL;
 static const char* vm_snapshot_instructions_filename = NULL;
 static const char* isolate_snapshot_data_filename = NULL;
 static const char* isolate_snapshot_instructions_filename = NULL;
 static const char* assembly_filename = NULL;
+static const char* script_snapshot_filename = NULL;
 
 
 // Value of the --package-root flag.
 // (This pointer points into an argv buffer and does not need to be
 // free'd.)
 static const char* commandline_package_root = NULL;
 
 // Value of the --packages flag.
 // (This pointer points into an argv buffer and does not need to be
 // free'd.)
@@ skipping 104 matching lines @@
 
 static const char* ProcessOption(const char* option, const char* name) {
   const intptr_t length = strlen(name);
   if (strncmp(option, name, length) == 0) {
     return (option + length);
   }
   return NULL;
 }
 
 
+static bool ProcessSnapshotKindOption(const char* option) {
+  const char* kind = ProcessOption(option, "--snapshot_kind=");
+  if (kind == NULL) {
+    return false;
+  }
+  if (strcmp(kind, "core") == 0) {
+    snapshot_kind = kCore;
+    return true;
+  } else if (strcmp(kind, "script") == 0) {
+    snapshot_kind = kScript;
+    return true;
+  } else if (strcmp(kind, "app-aot-blobs") == 0) {
+    snapshot_kind = kAppAOTBlobs;
+    return true;
+  } else if (strcmp(kind, "app-aot-assembly") == 0) {
+    snapshot_kind = kAppAOTAssembly;
+    return true;
+  }
+  Log::PrintErr(
+      "Unrecognized snapshot kind: '%s'\nValid kinds are: "
+      "core, script, app-aot-blobs, app-aot-assembly\n",
+      kind);
+  return false;
+}

[siva, 2017/02/14 03:56:09]

Can this also be moved to snapshot_utils.cc and shared with the version that
exists in main.cc

[rmacnak, 2017/02/14 23:39:39]

They're different: main.cc doesn't generate core snapshots and gen_snapshot.cc
doesn't generate app-jit snapshots.

Also sadly the argument parsers in gen_snapshot and main have different
signatures.

+
+
 static bool ProcessVmSnapshotDataOption(const char* option) {
   const char* name = ProcessOption(option, "--vm_snapshot_data=");
   if (name != NULL) {
     vm_snapshot_data_filename = name;
     return true;
   }
   return false;
 }
 
 
@@ skipping 30 matching lines @@
 static bool ProcessAssemblyOption(const char* option) {
   const char* name = ProcessOption(option, "--assembly=");
   if (name != NULL) {
     assembly_filename = name;
     return true;
   }
   return false;
 }
 
 
+static bool ProcessScriptSnapshotOption(const char* option) {
+  const char* name = ProcessOption(option, "--script_snapshot=");
+  if (name != NULL) {
+    script_snapshot_filename = name;
+    return true;
+  }
+  return false;
+}
+
+
 static bool ProcessEmbedderEntryPointsManifestOption(const char* option) {
   const char* name = ProcessOption(option, "--embedder_entry_points_manifest=");
   if (name != NULL) {
     entry_points_files->AddArgument(name);
     return true;
   }
   return false;
 }
 
 
@@ skipping 27 matching lines @@
   }
   if (mapping != NULL) {
     DartUtils::url_mapping->AddArgument(mapping);
     return true;
   }
   return false;
 }
 
 
 static bool IsSnapshottingForPrecompilation() {
-  return (assembly_filename != NULL) ||
-         (vm_snapshot_instructions_filename != NULL);
+  return (snapshot_kind == kAppAOTBlobs) || (snapshot_kind == kAppAOTAssembly);
 }
 
 
 // Parse out the command line arguments. Returns -1 if the arguments
 // are incorrect, 0 otherwise.
 static int ParseArguments(int argc,
                           char** argv,
                           CommandLineOptions* vm_options,
                           char** script_name) {
   const char* kPrefix = "-";
   const intptr_t kPrefixLen = strlen(kPrefix);
 
   // Skip the binary name.
   int i = 1;
 
   // Parse out the vm options.
   while ((i < argc) && IsValidFlag(argv[i], kPrefix, kPrefixLen)) {
-    if (ProcessVmSnapshotDataOption(argv[i]) ||
+    if (ProcessSnapshotKindOption(argv[i]) ||
+        ProcessVmSnapshotDataOption(argv[i]) ||
         ProcessVmSnapshotInstructionsOption(argv[i]) ||
         ProcessIsolateSnapshotDataOption(argv[i]) ||
         ProcessIsolateSnapshotInstructionsOption(argv[i]) ||
         ProcessAssemblyOption(argv[i]) ||
+        ProcessScriptSnapshotOption(argv[i]) ||
         ProcessEmbedderEntryPointsManifestOption(argv[i]) ||
         ProcessURLmappingOption(argv[i]) || ProcessPackageRootOption(argv[i]) ||
         ProcessPackagesOption(argv[i]) || ProcessEnvironmentOption(argv[i])) {
       i += 1;
       continue;
     }
     vm_options->AddArgument(argv[i]);
     i += 1;
   }
 
   // Get the script name.
   if (i < argc) {
     *script_name = argv[i];
     i += 1;
   } else {
     *script_name = NULL;
   }
 
   // Verify consistency of arguments.
   if ((commandline_package_root != NULL) &&
       (commandline_packages_file != NULL)) {
     Log::PrintErr(
         "Specifying both a packages directory and a packages "
-        "file is invalid.\n");
+        "file is invalid.\n\n");
     return -1;
   }
 
-  if (vm_snapshot_data_filename == NULL) {
-    Log::PrintErr("No vm snapshot output file specified.\n\n");
+  switch (snapshot_kind) {
+    case kNone: {
+      Log::PrintErr("No snapshot kind specified.\n\n");
+      return -1;
+    }
+    case kCore: {
+      if ((vm_snapshot_data_filename == NULL) ||
+          (isolate_snapshot_data_filename == NULL)) {
+        Log::PrintErr(
+            "Building a core snapshot requires specifying output "
+            "files for --vm_snapshot_data and --isolate_snapshot_data.\n\n");
+        return -1;
+      }
+      break;
+    }
+    case kScript: {
+      if ((vm_snapshot_data_filename == NULL) ||
+          (isolate_snapshot_data_filename == NULL) ||
+          (script_snapshot_filename == NULL)) {
+        Log::PrintErr(
+            "Building a script snapshot requires specifying input "
+            "files for --vm_snapshot_data and --isolate_snapshot_data and an "
+            "output file for --script-snapshot.\n\n");
+        return -1;
+      }
+      break;
+    }
+    case kAppAOTBlobs: {
+      if ((vm_snapshot_data_filename == NULL) ||
+          (vm_snapshot_instructions_filename == NULL) ||
+          (isolate_snapshot_data_filename == NULL) ||
+          (isolate_snapshot_instructions_filename == NULL)) {
+        Log::PrintErr(
+            "Building an AOT snapshot as blobs requires specifying "
+            "output files for --vm_snapshot_data, --vm_snapshot_instructions, "
+            "--isolate_snapshot_data and --isolate_snapshot_instructions.\n\n");
+        return -1;
+      }
+      break;
+    }
+    case kAppAOTAssembly: {
+      if (assembly_filename == NULL) {
+        Log::PrintErr(
+            "Building an AOT snapshot as assembly requires specifying "
+            "an output file for --assembly.\n\n");
+        return -1;
+      }
+      break;
+    }
+  }
+
+  if (IsSnapshottingForPrecompilation() && (entry_points_files->count() == 0)) {
+    Log::PrintErr(
+        "Building an AOT snapshot requires at least one embedder "
+        "entry points manifest.\n\n");
     return -1;
   }
 
-  if (isolate_snapshot_data_filename == NULL) {
-    Log::PrintErr("No isolate snapshot output file specified.\n\n");
-    return -1;
-  }
-
-  bool precompiled_as_assembly = assembly_filename != NULL;
-  bool precompiled_as_blobs = (vm_snapshot_instructions_filename != NULL) ||
-                              (isolate_snapshot_instructions_filename != NULL);
-  if (precompiled_as_assembly && precompiled_as_blobs) {
-    Log::PrintErr(
-        "Cannot request a precompiled snapshot simultaneously as "
-        "assembly (--assembly=<output.file>) and as blobs "
-        "(--instructions-blob=<output.file> and "
-        "--rodata-blob=<output.file>)\n\n");
-    return -1;
-  }
-  if ((vm_snapshot_instructions_filename != NULL) !=
-      (isolate_snapshot_instructions_filename != NULL)) {
-    Log::PrintErr(
-        "Requesting a precompiled snapshot as blobs requires both "
-        "(--vm_snapshot_instructions=<output.file> and "
-        "--isolate_snapshot_instructions=<output.file>)\n\n");
-    return -1;
-  }
-  if (IsSnapshottingForPrecompilation() && (entry_points_files->count() == 0)) {
-    Log::PrintErr(
-        "Specifying an instructions snapshot filename indicates precompilation"
-        ". But no embedder entry points manifest was specified.\n\n");
-    return -1;
-  }
-
   return 0;
 }
 
 
 static void WriteSnapshotFile(const char* filename,
                               const uint8_t* buffer,
-                              const intptr_t size) {
+                              const intptr_t size,
+                              bool write_magic_number = false) {
   File* file = File::Open(filename, File::kWriteTruncate);
   if (file == NULL) {
     Log::PrintErr("Error: Unable to write snapshot file: %s\n\n", filename);
     Dart_ExitScope();
     Dart_ShutdownIsolate();
     Dart_Cleanup();
     exit(kErrorExitCode);
   }
+  if (write_magic_number) {
+    // Write the magic number to indicate file is a script snapshot.
+    DartUtils::WriteMagicNumber(file);
+  }
   if (!file->WriteFully(buffer, size)) {
     Log::PrintErr("Error: Failed to write snapshot file.\n\n");
   }
   file->Release();
 }

[siva, 2017/02/14 03:56:09]

This function exists in snapshot_utils.cc, can we use that instead of defining
yet another one here?

[rmacnak, 2017/02/14 23:39:39]

The shutdown logic is different between gen_snapshot and main. Using
Snapshot::WriteScript here results in hangs on errors.

 
 
 class UriResolverIsolateScope {
  public:
   UriResolverIsolateScope() {
     ASSERT(isolate != NULL);
     snapshotted_isolate_ = Dart_CurrentIsolate();
     Dart_ExitIsolate();
     Dart_EnterIsolate(isolate);
     Dart_EnterScope();
@@ skipping 82 matching lines @@
   if (Dart_IsError(resolved_uri)) {
     return resolved_uri;
   }
   // Now load the contents of the specified uri.
   const char* resolved_uri_string = DartUtils::GetStringValue(resolved_uri);
   Dart_Handle source = LoadUrlContents(resolved_uri_string);
 
   if (Dart_IsError(source)) {
     return source;
   }
-  if (IsSnapshottingForPrecompilation()) {
+  if (snapshot_kind == kCore) {
+    return Dart_LoadLibrary(resolved_uri, Dart_Null(), source, 0, 0);
+  } else {
     return Dart_LoadScript(resolved_uri, Dart_Null(), source, 0, 0);
-  } else {
-    return Dart_LoadLibrary(resolved_uri, Dart_Null(), source, 0, 0);
   }
 }
 
 
 static Builtin::BuiltinLibraryId BuiltinId(const char* url) {
   if (DartUtils::IsDartBuiltinLibURL(url)) {
     return Builtin::kBuiltinLibrary;
   }
   if (DartUtils::IsDartIOLibURL(url)) {
     return Builtin::kIOLibrary;
@@ skipping 95 matching lines @@
   return lib;
 }
 
 
 // clang-format off
 static void PrintUsage() {
   Log::PrintErr(
 "Usage:                                                                      \n"
 " gen_snapshot [<vm-flags>] [<options>] [<dart-script-file>]                 \n"
 "                                                                            \n"
+" Global options:                                                            \n"
+"   --package_root=<path>             Where to find packages, that is,       \n"
+"                                     package:...  imports.                  \n"
+"                                                                            \n"
+"   --packages=<packages_file>        Where to find a package spec file      \n"
+"                                                                            \n"
+"   --url_mapping=<mapping>           Uses the URL mapping(s) specified on   \n"
+"                                     the command line to load the           \n"
+"                                     libraries.                             \n"
+"                                                                            \n"
+" To create a core snapshot:                                                 \n"
+"   --snapshot-kind=core                                                     \n"
+"   --vm_snapshot_data=<output-file>                                         \n"
+"   --isolate_snapshot_data=<output-file>                                    \n"
+"   [<dart-script-file>]                                                     \n"
+"                                                                            \n"
+" Writes a snapshot of <dart-script-file> to the specified snapshot files.   \n"
+" If no <dart-script-file> is passed, a generic snapshot of all the corelibs \n"
+" is created.                                                                \n"
+"                                                                            \n"
+" To create a script snapshot with respect to a given core snapshot:         \n"
+"   --snapshot-kind=script                                                   \n"
+"   --vm_snapshot_data=<intput-file>                                         \n"
+"   --isolate_snapshot_data=<intput-file>                                    \n"
+"   --script_snapshot=<output-file>                                          \n"
+"   <dart-script-file>                                                       \n"
+"                                                                            \n"
 "  Writes a snapshot of <dart-script-file> to the specified snapshot files.  \n"
 "  If no <dart-script-file> is passed, a generic snapshot of all the corelibs\n"
-"  is created. It is required to specify the VM isolate snapshot and the     \n"
-"  isolate snapshot. The other flags are related to precompilation and are   \n"
-"  optional.                                                                 \n"
+"  is created.                                                               \n"
 "                                                                            \n"
-"  Precompilation:                                                           \n"
-"  In order to configure the snapshotter for precompilation, either          \n"
-"  --assembly=outputfile or --instructions_blob=outputfile1 and              \n"
-"  --rodata_blob=outputfile2 must be specified. If the former is choosen,    \n"
-"  assembly for the target architecture will be output into the given file,  \n"
-"  which must be compiled separately and either statically linked or         \n"
-"  dynamically loaded in the target executable. The symbols                  \n"
-"  kInstructionsSnapshot and kDataSnapshot must be passed to Dart_Initialize.\n"
-"  If the latter is choosen, binary data is output into the given files,     \n"
-"  which should be mmapped and passed to Dart_Initialize, with the           \n"
-"  instruction blob being mapped as executable.                              \n"
-"  In both cases, a entry points manifest must be given to list the places   \n"
-"  in the Dart program the embedder calls from the C API (Dart_Invoke, etc). \n"
-"  Not specifying these may cause the tree shaker to remove them from the    \n"
-"  program. The format of this manifest is as follows. Each line in the      \n"
-"  manifest is a comma separated list of three elements. The first entry is  \n"
-"  the library URI, the second entry is the class name and the final entry   \n"
-"  the function name. The file must be terminated with a newline charater.   \n"
+" To create an AOT application snapshot as blobs suitable for loading with   \n"
+" mmap:                                                                      \n"
+"   --snapshot-kind=app-aot-blobs                                            \n"
+"   --vm_snapshot_data=<output-file>                                         \n"
+"   --vm_snapshot_instructions=<output-file>                                 \n"
+"   --isolate_snapshot_data=<output-file>                                    \n"
+"   --isolate_snapshot_instructions=<output-file>                            \n"
+"   {--embedder_entry_points_manifest=<input-file>}                          \n"
+"   <dart-script-file>                                                       \n"
 "                                                                            \n"
-"    Example:                                                                \n"
-"      dart:something,SomeClass,doSomething                                  \n"
+" To create an AOT application snapshot as assembly suitable for compilation \n"
+" as a static or dynamic library:                                            \n"
+" mmap:                                                                      \n"
+"   --snapshot-kind=app-aot-blobs                                            \n"
+"   --assembly=<output-file>                                                 \n"
+"   {--embedder_entry_points_manifest=<input-file>}                          \n"
+"   <dart-script-file>                                                       \n"
 "                                                                            \n"
-"  Supported options:                                                        \n"
-"    --vm_snapshot_data=<file>         A full snapshot is a compact          \n"
-"    --isolate_snapshot_data=<file>    representation of the dart vm isolate \n"
-"                                      heap and dart isolate heap states.    \n"
-"                                      Both these options are required       \n"
+" AOT snapshots require entry points manifest files, which list the places   \n"
+" in the Dart program the embedder calls from the C API (Dart_Invoke, etc).  \n"
+" Not specifying these may cause the tree shaker to remove them from the     \n"
+" program. The format of this manifest is as follows. Each line in the       \n"
+" manifest is a comma separated list of three elements. The first entry is   \n"
+" the library URI, the second entry is the class name and the final entry    \n"
+" the function name. The file must be terminated with a newline charater.    \n"
 "                                                                            \n"
-"    --package_root=<path>             Where to find packages, that is,      \n"
-"                                      package:...  imports.                 \n"
-"                                                                            \n"
-"    --packages=<packages_file>        Where to find a package spec file     \n"
-"                                                                            \n"
-"    --url_mapping=<mapping>           Uses the URL mapping(s) specified on  \n"
-"                                      the command line to load the          \n"
-"                                      libraries.                            \n"
-"                                                                            \n"
-"    --assembly=<file>                 (Precompilation only) Contains the    \n"
-"                                      assembly that must be linked into     \n"
-"                                      the target binary                     \n"
-"                                                                            \n"
-"    --vm_snapshot_instructions=<file> (Precompilation only) Contains the    \n"
-"    --isolate_snapshot_instructions=<file> instructions and read-only data  \n"
-"                                      that must be mapped into the target   \n"
-"                                      binary                                \n"
-"                                                                            \n"
-"    --embedder_entry_points_manifest=<file> (Precompilation or app          \n"
-"                                      snapshots) Contains embedder's entry  \n"
-"                                      points into Dart code from the C API. \n"
+"   Example:                                                                 \n"
+"     dart:something,SomeClass,doSomething                                   \n"
 "\n");
 }
 // clang-format on
 
 
 static void VerifyLoaded(Dart_Handle library) {
   if (Dart_IsError(library)) {
     const char* err_msg = Dart_GetError(library);
     Log::PrintErr("Errors encountered while loading: %s\n", err_msg);
     CHECK_RESULT(library);
@@ skipping 339 matching lines @@
   Dart_QualifiedFunctionName* entries = ParseEntryPointsManifestFiles();
   if ((entries == NULL) && IsSnapshottingForPrecompilation()) {
     Log::PrintErr(
         "Could not find native embedder entry points during precompilation\n");
     exit(kErrorExitCode);
   }
   return entries;
 }
 
 
-static void CreateAndWriteSnapshot() {
-  ASSERT(!IsSnapshottingForPrecompilation());
+static void CreateAndWriteCoreSnapshot() {
+  ASSERT(snapshot_kind == kCore);
+  ASSERT(vm_snapshot_data_filename != NULL);
+  ASSERT(isolate_snapshot_data_filename != NULL);
+
   Dart_Handle result;
   uint8_t* vm_snapshot_data_buffer = NULL;
   intptr_t vm_snapshot_data_size = 0;
   uint8_t* isolate_snapshot_data_buffer = NULL;
   intptr_t isolate_snapshot_data_size = 0;
 
   // First create a snapshot.
   result = Dart_CreateSnapshot(&vm_snapshot_data_buffer, &vm_snapshot_data_size,
                                &isolate_snapshot_data_buffer,
                                &isolate_snapshot_data_size);
   CHECK_RESULT(result);
 
   // Now write the vm isolate and isolate snapshots out to the
   // specified file and exit.
   WriteSnapshotFile(vm_snapshot_data_filename, vm_snapshot_data_buffer,
                     vm_snapshot_data_size);
   WriteSnapshotFile(isolate_snapshot_data_filename,
                     isolate_snapshot_data_buffer, isolate_snapshot_data_size);
-  Dart_ExitScope();
-
-  // Shutdown the isolate.
-  Dart_ShutdownIsolate();
 }
 
 
+static void CreateAndWriteScriptSnapshot() {
+  ASSERT(snapshot_kind == kScript);
+  ASSERT(script_snapshot_filename != NULL);
+
+  // First create a snapshot.
+  uint8_t* buffer = NULL;
+  intptr_t size = 0;
+  Dart_Handle result = Dart_CreateScriptSnapshot(&buffer, &size);
+  CHECK_RESULT(result);
+
+  // Now write it out to the specified file.
+  WriteSnapshotFile(script_snapshot_filename, buffer, size, true);
+}
+
+
 static void CreateAndWritePrecompiledSnapshot(
     Dart_QualifiedFunctionName* standalone_entry_points) {
   ASSERT(IsSnapshottingForPrecompilation());
   Dart_Handle result;
 
   // Precompile with specified embedder entry points
   result = Dart_Precompile(standalone_entry_points, NULL, 0);
   CHECK_RESULT(result);
 
   // Create a precompiled snapshot.
   bool as_assembly = assembly_filename != NULL;
   if (as_assembly) {
+    ASSERT(snapshot_kind == kAppAOTAssembly);
+
     uint8_t* assembly_buffer = NULL;
     intptr_t assembly_size = 0;
     result =
         Dart_CreateAppAOTSnapshotAsAssembly(&assembly_buffer, &assembly_size);
     CHECK_RESULT(result);
+
     WriteSnapshotFile(assembly_filename, assembly_buffer, assembly_size);
   } else {
+    ASSERT(snapshot_kind == kAppAOTBlobs);
+
     uint8_t* vm_snapshot_data_buffer = NULL;
     intptr_t vm_snapshot_data_size = 0;
     uint8_t* vm_snapshot_instructions_buffer = NULL;
     intptr_t vm_snapshot_instructions_size = 0;
     uint8_t* isolate_snapshot_data_buffer = NULL;
     intptr_t isolate_snapshot_data_size = 0;
     uint8_t* isolate_snapshot_instructions_buffer = NULL;
     intptr_t isolate_snapshot_instructions_size = 0;
     result = Dart_CreateAppAOTSnapshotAsBlobs(
         &vm_snapshot_data_buffer, &vm_snapshot_data_size,
         &vm_snapshot_instructions_buffer, &vm_snapshot_instructions_size,
         &isolate_snapshot_data_buffer, &isolate_snapshot_data_size,
         &isolate_snapshot_instructions_buffer,
         &isolate_snapshot_instructions_size);
     CHECK_RESULT(result);
+
     WriteSnapshotFile(vm_snapshot_data_filename, vm_snapshot_data_buffer,
                       vm_snapshot_data_size);
     WriteSnapshotFile(vm_snapshot_instructions_filename,
                       vm_snapshot_instructions_buffer,
                       vm_snapshot_instructions_size);
     WriteSnapshotFile(isolate_snapshot_data_filename,
                       isolate_snapshot_data_buffer, isolate_snapshot_data_size);
     WriteSnapshotFile(isolate_snapshot_instructions_filename,
                       isolate_snapshot_instructions_buffer,
                       isolate_snapshot_instructions_size);
   }
-
-  Dart_ExitScope();
-
-  // Shutdown the isolate.
-  Dart_ShutdownIsolate();
 }
 
 
 static void SetupForUriResolution() {
   // Set up the library tag handler for this isolate.
   Dart_Handle result = Dart_SetLibraryTagHandler(Loader::LibraryTagHandler);
   if (Dart_IsError(result)) {
-    Log::PrintErr("%s", Dart_GetError(result));
+    Log::PrintErr("%s\n", Dart_GetError(result));
     Dart_ExitScope();
     Dart_ShutdownIsolate();
     exit(kErrorExitCode);
   }
   // This is a generic dart snapshot which needs builtin library setup.
   Dart_Handle library =
       LoadGenericSnapshotCreationScript(Builtin::kBuiltinLibrary);
   VerifyLoaded(library);
 }
 
@@ skipping 17 matching lines @@
 static Dart_Isolate CreateServiceIsolate(const char* script_uri,
                                          const char* main,
                                          const char* package_root,
                                          const char* package_config,
                                          Dart_IsolateFlags* flags,
                                          void* data,
                                          char** error) {
   IsolateData* isolate_data =
       new IsolateData(script_uri, package_root, package_config);
   Dart_Isolate isolate = NULL;
-  isolate = Dart_CreateIsolate(script_uri, main, NULL, NULL, NULL, isolate_data,
-                               error);
+  isolate = Dart_CreateIsolate(script_uri, main, isolate_snapshot_data, NULL,
+                               NULL, isolate_data, error);
 
   if (isolate == NULL) {
-    Log::PrintErr("Error: Could not create service isolate");
+    Log::PrintErr("Error: Could not create service isolate\n");
     return NULL;
   }
 
   Dart_EnterScope();
   if (!Dart_IsServiceIsolate(isolate)) {
-    Log::PrintErr("Error: We only expect to create the service isolate");
+    Log::PrintErr("Error: We only expect to create the service isolate\n");
     return NULL;
   }
   Dart_Handle result = Dart_SetLibraryTagHandler(Loader::LibraryTagHandler);
+  if (Dart_IsError(result)) {
+    Log::PrintErr("Error: Could not set tag handler for service isolate\n");
+    return NULL;
+  }
   // Setup the native resolver.
   Builtin::LoadAndCheckLibrary(Builtin::kBuiltinLibrary);
   Builtin::LoadAndCheckLibrary(Builtin::kIOLibrary);
-  if (Dart_IsError(result)) {
-    Log::PrintErr("Error: Could not set tag handler for service isolate");
-    return NULL;
-  }
-  CHECK_RESULT(result);
+
   ASSERT(Dart_IsServiceIsolate(isolate));
   // Load embedder specific bits and return. Will not start http server.
   if (!VmService::Setup("127.0.0.1", -1, false /* running_precompiled */,
                         false /* server dev mode */)) {
     *error = strdup(VmService::GetErrorMessage());
     return NULL;
   }
   Dart_ExitScope();
   Dart_ExitIsolate();
   return isolate;
@@ skipping 52 matching lines @@
   init_params.version = DART_INITIALIZE_PARAMS_CURRENT_VERSION;
   if (app_script_name != NULL) {
     init_params.create = CreateServiceIsolate;
   }
   init_params.file_open = DartUtils::OpenFile;
   init_params.file_read = DartUtils::ReadFile;
   init_params.file_write = DartUtils::WriteFile;
   init_params.file_close = DartUtils::CloseFile;
   init_params.entropy_source = DartUtils::EntropySource;
 
+  if (snapshot_kind == kScript) {
+    File* file = File::Open(vm_snapshot_data_filename, File::kRead);
+    if (file == NULL) {
+      Log::PrintErr("Failed to open: %s\n", vm_snapshot_data_filename);
+      return kErrorExitCode;
+    }
+    void* buffer = file->Map(File::kReadOnly, 0, file->Length());
+    if (buffer == NULL) {
+      Log::PrintErr("Failed to read: %s\n", vm_snapshot_data_filename);
+      return kErrorExitCode;
+    }
+    file->Close();
+    init_params.vm_snapshot_data = reinterpret_cast<const uint8_t*>(buffer);
+
+    file = File::Open(isolate_snapshot_data_filename, File::kRead);
+    if (file == NULL) {
+      Log::PrintErr("Failed to open: %s\n", isolate_snapshot_data_filename);
+      return kErrorExitCode;
+    }
+    buffer = file->Map(File::kReadOnly, 0, file->Length());
+    if (buffer == NULL) {
+      Log::PrintErr("Failed to read: %s\n", isolate_snapshot_data_filename);
+      return kErrorExitCode;
+    }
+    file->Close();
+    isolate_snapshot_data = reinterpret_cast<const uint8_t*>(buffer);
+  }
+
   char* error = Dart_Initialize(&init_params);
   if (error != NULL) {
     Log::PrintErr("VM initialization failed: %s\n", error);
     free(error);
     return kErrorExitCode;
   }
 
   IsolateData* isolate_data = new IsolateData(NULL, commandline_package_root,
                                               commandline_packages_file);
-  Dart_Isolate isolate =
-      Dart_CreateIsolate(NULL, NULL, NULL, NULL, NULL, isolate_data, &error);
+  Dart_Isolate isolate = Dart_CreateIsolate(NULL, NULL, isolate_snapshot_data,
+                                            NULL, NULL, isolate_data, &error);
   if (isolate == NULL) {
-    Log::PrintErr("Error: %s", error);
+    Log::PrintErr("Error: %s\n", error);
     free(error);
     exit(kErrorExitCode);
   }
 
   Dart_Handle result;
   Dart_Handle library;
   Dart_EnterScope();
 
   result = Dart_SetEnvironmentCallback(EnvironmentCallback);
   CHECK_RESULT(result);
@@ skipping 39 matching lines @@
     void* kernel_program = NULL;
     if (is_kernel_file) {
       kernel_program = Dart_ReadKernelBinary(kernel, kernel_length);
       free(const_cast<uint8_t*>(kernel));
     }
 
     Dart_Isolate isolate =
         is_kernel_file
             ? Dart_CreateIsolateFromKernel(NULL, NULL, kernel_program, NULL,
                                            isolate_data, &error)
-            : Dart_CreateIsolate(NULL, NULL, NULL, NULL, NULL, isolate_data,
-                                 &error);
+            : Dart_CreateIsolate(NULL, NULL, isolate_snapshot_data, NULL, NULL,
+                                 isolate_data, &error);
     if (isolate == NULL) {
-      Log::PrintErr("%s", error);
+      Log::PrintErr("%s\n", error);
       free(error);
       exit(kErrorExitCode);
     }
     Dart_EnterScope();
     result = Dart_SetEnvironmentCallback(EnvironmentCallback);
     CHECK_RESULT(result);
 
     // Set up the library tag handler in such a manner that it will use the
     // URL mapping specified on the command line to load the libraries.
     result = Dart_SetLibraryTagHandler(CreateSnapshotLibraryTagHandler);
@@ skipping 21 matching lines @@
       library = LoadSnapshotCreationScript(app_script_name);
       VerifyLoaded(library);
 
       ImportNativeEntryPointLibrariesIntoRoot(entry_points);
     }
 
     // Ensure that we mark all libraries as loaded.
     result = Dart_FinalizeLoading(false);
     CHECK_RESULT(result);
 
-    if (!IsSnapshottingForPrecompilation()) {
-      CreateAndWriteSnapshot();
-    } else {
-      CreateAndWritePrecompiledSnapshot(entry_points);
+    switch (snapshot_kind) {
+      case kCore:
+        CreateAndWriteCoreSnapshot();
+        break;
+      case kScript:
+        CreateAndWriteScriptSnapshot();
+        break;
+      case kAppAOTBlobs:
+      case kAppAOTAssembly:
+        CreateAndWritePrecompiledSnapshot(entry_points);
+        break;
+      default:
+        UNREACHABLE();
     }
 
+    Dart_ExitScope();
+    Dart_ShutdownIsolate();
+
     CleanupEntryPointsCollection(entry_points);
 
     Dart_EnterIsolate(UriResolverIsolateScope::isolate);
     Dart_ShutdownIsolate();
   } else {
     SetupForGenericSnapshotCreation();
-    CreateAndWriteSnapshot();
+    CreateAndWriteCoreSnapshot();
+
+    Dart_ExitScope();
+    Dart_ShutdownIsolate();
   }
   error = Dart_Cleanup();
   if (error != NULL) {
     Log::PrintErr("VM cleanup failed: %s\n", error);
     free(error);
   }
   EventHandler::Stop();
   return 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   return dart::bin::main(argc, argv);
 }