runtime/vm/bootstrap.cc - sdk - Git at Google

 // Copyright (c) 2012, 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.

 #include "vm/bootstrap.h"

 #include "include/dart_api.h"

 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler/jit/compiler.h"
 #include "vm/dart_api_impl.h"
 #if !defined(DART_PRECOMPILED_RUNTIME)
 #include "vm/kernel.h"
 #include "vm/kernel_loader.h"
 #endif
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/symbols.h"

 namespace dart {

 struct BootstrapLibProps {
   ObjectStore::BootstrapLibraryId index;
   const char* uri;
   const char** source_paths;
   const char* patch_uri;
   const char** patch_paths;
 };

 enum { kPathsUriOffset = 0, kPathsSourceOffset = 1, kPathsEntryLength = 2 };

 const char** Bootstrap::profiler_patch_paths_ = NULL;

 #define MAKE_PROPERTIES(CamelName, name)                                       \
   {ObjectStore::k##CamelName, "dart:" #name, Bootstrap::name##_source_paths_,  \
    "dart:" #name "-patch", Bootstrap::name##_patch_paths_},

 static const BootstrapLibProps bootstrap_libraries[] = {
     FOR_EACH_BOOTSTRAP_LIBRARY(MAKE_PROPERTIES)};

 #undef MAKE_PROPERTIES

 static const intptr_t kBootstrapLibraryCount = ARRAY_SIZE(bootstrap_libraries);

 static RawString* GetLibrarySourceByIndex(intptr_t index,
                                           const String& uri,
                                           bool patch) {
   ASSERT(index >= 0 && index < kBootstrapLibraryCount);

   // Try to read the source using the path specified for the uri.
   const char** source_paths = patch ? bootstrap_libraries[index].patch_paths
                                     : bootstrap_libraries[index].source_paths;
   if (source_paths == NULL) {
     return String::null();  // No path mapping information exists for library.
   }
   const char* source_data = NULL;
   for (intptr_t i = 0; source_paths[i] != NULL; i += kPathsEntryLength) {
     if (uri.Equals(source_paths[i + kPathsUriOffset])) {
       source_data = source_paths[i + kPathsSourceOffset];
       break;
     }
   }
   if (source_data == NULL) {
     return String::null();  // Uri does not exist in path mapping information.
   }

   const uint8_t* utf8_array = NULL;
   intptr_t file_length = -1;

   if (source_data != NULL) {
     file_length = strlen(source_data);
     utf8_array = reinterpret_cast<const uint8_t*>(source_data);
   } else {
     return String::null();
   }
   ASSERT(utf8_array != NULL);
   ASSERT(file_length >= 0);
   return String::FromUTF8(utf8_array, file_length);
 }

 static RawString* GetLibrarySource(Zone* zone,
                                    const Library& lib,
                                    const String& uri,
                                    bool patch) {
   // First check if this is a valid bootstrap library and find its index in
   // the 'bootstrap_libraries' table above.
   intptr_t index;
   const String& lib_uri = String::Handle(lib.url());
   for (index = 0; index < kBootstrapLibraryCount; ++index) {
     if (lib_uri.Equals(bootstrap_libraries[index].uri)) {
       break;
     }
   }
   if (index == kBootstrapLibraryCount) {
     return String::null();  // The library is not a bootstrap library.
   }

   const Array& strings = Array::Handle(zone, Array::New(3));
   strings.SetAt(0, lib_uri);
   strings.SetAt(1, Symbols::Slash());
   strings.SetAt(2, uri);
   const String& part_uri = String::Handle(zone, String::ConcatAll(strings));

   return GetLibrarySourceByIndex(index, part_uri, patch);
 }

 static RawError* Compile(const Library& library, const Script& script) {
   bool update_lib_status = (script.kind() == RawScript::kScriptTag ||
                             script.kind() == RawScript::kLibraryTag);
   if (update_lib_status) {
     library.SetLoadInProgress();
   }
   const Error& error = Error::Handle(Compiler::Compile(library, script));
   if (update_lib_status) {
     if (error.IsNull()) {
       library.SetLoaded();
     } else {
       // Compilation errors are not Dart instances, so just mark the library
       // as having failed to load without providing an error instance.
       library.SetLoadError(Object::null_instance());
     }
   }
   return error.raw();
 }

 static Dart_Handle LoadPartSource(Thread* thread,
                                   const Library& lib,
                                   const String& uri) {
   Zone* zone = thread->zone();
   const String& part_source =
       String::Handle(zone, GetLibrarySource(zone, lib, uri, false));
   const String& lib_uri = String::Handle(zone, lib.url());
   if (part_source.IsNull()) {
     return Api::NewError("Unable to read part file '%s' of library '%s'",
                          uri.ToCString(), lib_uri.ToCString());
   }

   // Prepend the library URI to form a unique script URI for the part.
   const Array& strings = Array::Handle(zone, Array::New(3));
   strings.SetAt(0, lib_uri);
   strings.SetAt(1, Symbols::Slash());
   strings.SetAt(2, uri);
   const String& part_uri = String::Handle(zone, String::ConcatAll(strings));

   // Create a script object and compile the part.
   const Script& part_script = Script::Handle(
       zone, Script::New(part_uri, part_source, RawScript::kSourceTag));
   const Error& error = Error::Handle(zone, Compile(lib, part_script));
   return Api::NewHandle(thread, error.raw());
 }

 static Dart_Handle BootstrapLibraryTagHandler(Dart_LibraryTag tag,
                                               Dart_Handle library,
                                               Dart_Handle uri) {
   Thread* thread = Thread::Current();
   Zone* zone = thread->zone();
   // This handler calls into the VM directly and does not use the Dart
   // API so we transition back to VM.
   TransitionNativeToVM transition(thread);
   if (!Dart_IsLibrary(library)) {
     return Api::NewError("not a library");
   }
   if (!Dart_IsString(uri)) {
     return Api::NewError("uri is not a string");
   }
   if (tag == Dart_kCanonicalizeUrl) {
     // In the bootstrap loader we do not try and do any canonicalization.
     return uri;
   }
   const String& uri_str = Api::UnwrapStringHandle(zone, uri);
   ASSERT(!uri_str.IsNull());
   if (tag == Dart_kImportTag) {
     // We expect the core bootstrap libraries to only import other
     // core bootstrap libraries.
     // We have precreated all the bootstrap library objects hence
     // we do not expect to be called back with the tag set to kImportTag.
     // The bootstrap process explicitly loads all the libraries one by one.
     return Api::NewError("Invalid import of '%s' in a bootstrap library",
                          uri_str.ToCString());
   }
   ASSERT(tag == Dart_kSourceTag);
   const Library& lib = Api::UnwrapLibraryHandle(zone, library);
   ASSERT(!lib.IsNull());
   return LoadPartSource(thread, lib, uri_str);
 }

 static RawError* LoadPatchFiles(Thread* thread,
                                 const Library& lib,
                                 intptr_t index) {
   const char** patch_files = bootstrap_libraries[index].patch_paths;
   if (patch_files == NULL) return Error::null();

   Zone* zone = thread->zone();
   String& patch_uri = String::Handle(
       zone, Symbols::New(thread, bootstrap_libraries[index].patch_uri));
   String& patch_file_uri = String::Handle(zone);
   String& source = String::Handle(zone);
   Script& script = Script::Handle(zone);
   Error& error = Error::Handle(zone);
   const Array& strings = Array::Handle(zone, Array::New(3));
   strings.SetAt(0, patch_uri);
   strings.SetAt(1, Symbols::Slash());
   for (intptr_t j = 0; patch_files[j] != NULL; j += kPathsEntryLength) {
     patch_file_uri = String::New(patch_files[j + kPathsUriOffset]);
     source = GetLibrarySourceByIndex(index, patch_file_uri, true);
     if (source.IsNull()) {
       const String& message = String::Handle(
           String::NewFormatted("Unable to find dart patch source for %s",
                                patch_file_uri.ToCString()));
       return ApiError::New(message);
     }
     // Prepend the patch library URI to form a unique script URI for the patch.
     strings.SetAt(2, patch_file_uri);
     patch_file_uri = String::ConcatAll(strings);
     script = Script::New(patch_file_uri, source, RawScript::kPatchTag);
     error = lib.Patch(script);
     if (!error.IsNull()) {
       return error.raw();
     }
   }
   return Error::null();
 }

 static void Finish(Thread* thread) {
   Bootstrap::SetupNativeResolver();
   if (!ClassFinalizer::ProcessPendingClasses()) {
     FATAL("Error in class finalization during bootstrapping.");
   }

   // Eagerly compile the _Closure class as it is the class of all closure
   // instances. This allows us to just finalize function types without going
   // through the hoops of trying to compile their scope class.
   ObjectStore* object_store = thread->isolate()->object_store();
   Zone* zone = thread->zone();
   Class& cls = Class::Handle(zone, object_store->closure_class());
   Compiler::CompileClass(cls);

 #if defined(DEBUG)
   // Verify that closure field offsets are identical in Dart and C++.
   const Array& fields = Array::Handle(zone, cls.fields());
   ASSERT(fields.Length() == 6);
   Field& field = Field::Handle(zone);
   field ^= fields.At(0);
   ASSERT(field.Offset() == Closure::instantiator_type_arguments_offset());
   field ^= fields.At(1);
   ASSERT(field.Offset() == Closure::function_type_arguments_offset());
   field ^= fields.At(2);
   ASSERT(field.Offset() == Closure::delayed_type_arguments_offset());
   field ^= fields.At(3);
   ASSERT(field.Offset() == Closure::function_offset());
   field ^= fields.At(4);
   ASSERT(field.Offset() == Closure::context_offset());
   field ^= fields.At(5);
   ASSERT(field.Offset() == Closure::hash_offset());
 #endif  // defined(DEBUG)

   // Eagerly compile Bool class, bool constants are used from within compiler.
   cls = object_store->bool_class();
   Compiler::CompileClass(cls);
 }

 static RawError* BootstrapFromSource(Thread* thread) {
   Isolate* isolate = thread->isolate();
   Zone* zone = thread->zone();
   String& uri = String::Handle(zone);
   String& source = String::Handle(zone);
   Script& script = Script::Handle(zone);
   Library& lib = Library::Handle(zone);
   Error& error = Error::Handle(zone);

   // Set the library tag handler for the isolate to the bootstrap
   // library tag handler so that we can load all the bootstrap libraries.
   Dart_LibraryTagHandler saved_tag_handler = isolate->library_tag_handler();
   isolate->set_library_tag_handler(BootstrapLibraryTagHandler);

   // Load, compile and patch bootstrap libraries.
   for (intptr_t i = 0; i < kBootstrapLibraryCount; ++i) {
     ObjectStore::BootstrapLibraryId id = bootstrap_libraries[i].index;
     uri = Symbols::New(thread, bootstrap_libraries[i].uri);
     lib = isolate->object_store()->bootstrap_library(id);
     ASSERT(!lib.IsNull());
     ASSERT(lib.raw() == Library::LookupLibrary(thread, uri));
     source = GetLibrarySourceByIndex(i, uri, false);
     if (source.IsNull()) {
       const String& message = String::Handle(String::NewFormatted(
           "Unable to find dart source for %s", uri.ToCString()));
       error ^= ApiError::New(message);
       break;
     }
     script = Script::New(uri, source, RawScript::kLibraryTag);
     error = Compile(lib, script);
     if (!error.IsNull()) {
       break;
     }
     // If a patch exists, load and patch the script.
     error = LoadPatchFiles(thread, lib, i);
     if (!error.IsNull()) {
       break;
     }
   }

   if (error.IsNull()) {
     Finish(thread);
   }
   // Restore the library tag handler for the isolate.
   isolate->set_library_tag_handler(saved_tag_handler);

   return error.raw();
 }

 #if !defined(DART_PRECOMPILED_RUNTIME)
 static RawError* BootstrapFromKernel(Thread* thread,
                                      const uint8_t* kernel_buffer,
                                      intptr_t kernel_buffer_size) {
   Zone* zone = thread->zone();
   const char* error = nullptr;
   kernel::Program* program = kernel::Program::ReadFromBuffer(
       kernel_buffer, kernel_buffer_size, &error);
   if (program == nullptr) {
     const intptr_t kMessageBufferSize = 512;
     char message_buffer[kMessageBufferSize];
     Utils::SNPrint(message_buffer, kMessageBufferSize,
                    "Can't load Kernel binary: %s.", error);
     const String& msg = String::Handle(String::New(message_buffer, Heap::kOld));
     return ApiError::New(msg, Heap::kOld);
   }
   kernel::KernelLoader loader(program);
   Isolate* isolate = thread->isolate();

   // Load the bootstrap libraries in order (see object_store.h).
   Library& library = Library::Handle(zone);
   String& dart_name = String::Handle(zone);
   for (intptr_t i = 0; i < kBootstrapLibraryCount; ++i) {
     ObjectStore::BootstrapLibraryId id = bootstrap_libraries[i].index;
     library = isolate->object_store()->bootstrap_library(id);
     dart_name = library.url();
     for (intptr_t j = 0; j < program->library_count(); ++j) {
       const String& kernel_name = loader.LibraryUri(j);
       if (kernel_name.Equals(dart_name)) {
         loader.LoadLibrary(j);
         break;
       }
     }
   }

   // Finish bootstrapping, including class finalization.
   Finish(thread);

   // The platform binary may contain other libraries (e.g., dart:_builtin or
   // dart:io) that will not be bundled with application.  Load them now.
   const Object& result = Object::Handle(zone, loader.LoadProgram());
   delete program;
   if (result.IsError()) {
     return Error::Cast(result).raw();
   }

   // The builtin library should be registered with the VM.
   dart_name = String::New("dart:_builtin");
   library = Library::LookupLibrary(thread, dart_name);
   isolate->object_store()->set_builtin_library(library);

   return Error::null();
 }
 #else
 static RawError* BootstrapFromKernel(Thread* thread,
                                      const uint8_t* kernel_buffer,
                                      intptr_t kernel_buffer_size) {
   UNREACHABLE();
   return Error::null();
 }
 #endif

 RawError* Bootstrap::DoBootstrapping(const uint8_t* kernel_buffer,
                                      intptr_t kernel_buffer_size) {
   Thread* thread = Thread::Current();
   Isolate* isolate = thread->isolate();
   Zone* zone = thread->zone();
   String& uri = String::Handle(zone);
   Library& lib = Library::Handle(zone);

   HANDLESCOPE(thread);

   // Ensure there are library objects for all the bootstrap libraries.
   for (intptr_t i = 0; i < kBootstrapLibraryCount; ++i) {
     ObjectStore::BootstrapLibraryId id = bootstrap_libraries[i].index;
     uri = Symbols::New(thread, bootstrap_libraries[i].uri);
     lib = isolate->object_store()->bootstrap_library(id);
     ASSERT(lib.raw() == Library::LookupLibrary(thread, uri));
     if (lib.IsNull()) {
       lib = Library::NewLibraryHelper(uri, false);
       lib.SetLoadRequested();
       lib.Register(thread);
       isolate->object_store()->set_bootstrap_library(id, lib);
     }
   }

   return (kernel_buffer == NULL)
              ? BootstrapFromSource(thread)
              : BootstrapFromKernel(thread, kernel_buffer, kernel_buffer_size);
 }

 }  // namespace dart
	// Copyright (c) 2012, 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.

	#include "vm/bootstrap.h"

	#include "include/dart_api.h"

	#include "vm/bootstrap_natives.h"
	#include "vm/class_finalizer.h"
	#include "vm/compiler/jit/compiler.h"
	#include "vm/dart_api_impl.h"
	#if !defined(DART_PRECOMPILED_RUNTIME)
	#include "vm/kernel.h"
	#include "vm/kernel_loader.h"
	#endif
	#include "vm/object.h"
	#include "vm/object_store.h"
	#include "vm/symbols.h"

	namespace dart {

	struct BootstrapLibProps {
	ObjectStore::BootstrapLibraryId index;
	const char* uri;
	const char** source_paths;
	const char* patch_uri;
	const char** patch_paths;
	};

	enum { kPathsUriOffset = 0, kPathsSourceOffset = 1, kPathsEntryLength = 2 };

	const char** Bootstrap::profiler_patch_paths_ = NULL;

	#define MAKE_PROPERTIES(CamelName, name) \
	{ObjectStore::k##CamelName, "dart:" #name, Bootstrap::name##_source_paths_, \
	"dart:" #name "-patch", Bootstrap::name##_patch_paths_},

	static const BootstrapLibProps bootstrap_libraries[] = {
	FOR_EACH_BOOTSTRAP_LIBRARY(MAKE_PROPERTIES)};

	#undef MAKE_PROPERTIES

	static const intptr_t kBootstrapLibraryCount = ARRAY_SIZE(bootstrap_libraries);

	static RawString* GetLibrarySourceByIndex(intptr_t index,
	const String& uri,
	bool patch) {
	ASSERT(index >= 0 && index < kBootstrapLibraryCount);

	// Try to read the source using the path specified for the uri.
	const char** source_paths = patch ? bootstrap_libraries[index].patch_paths
	: bootstrap_libraries[index].source_paths;
	if (source_paths == NULL) {
	return String::null(); // No path mapping information exists for library.
	}
	const char* source_data = NULL;
	for (intptr_t i = 0; source_paths[i] != NULL; i += kPathsEntryLength) {
	if (uri.Equals(source_paths[i + kPathsUriOffset])) {
	source_data = source_paths[i + kPathsSourceOffset];
	break;
	}
	}
	if (source_data == NULL) {
	return String::null(); // Uri does not exist in path mapping information.
	}

	const uint8_t* utf8_array = NULL;
	intptr_t file_length = -1;

	if (source_data != NULL) {
	file_length = strlen(source_data);
	utf8_array = reinterpret_cast<const uint8_t*>(source_data);
	} else {
	return String::null();
	}
	ASSERT(utf8_array != NULL);
	ASSERT(file_length >= 0);
	return String::FromUTF8(utf8_array, file_length);
	}

	static RawString* GetLibrarySource(Zone* zone,
	const Library& lib,
	const String& uri,
	bool patch) {
	// First check if this is a valid bootstrap library and find its index in
	// the 'bootstrap_libraries' table above.
	intptr_t index;
	const String& lib_uri = String::Handle(lib.url());
	for (index = 0; index < kBootstrapLibraryCount; ++index) {
	if (lib_uri.Equals(bootstrap_libraries[index].uri)) {
	break;
	}
	}
	if (index == kBootstrapLibraryCount) {
	return String::null(); // The library is not a bootstrap library.
	}

	const Array& strings = Array::Handle(zone, Array::New(3));
	strings.SetAt(0, lib_uri);
	strings.SetAt(1, Symbols::Slash());
	strings.SetAt(2, uri);
	const String& part_uri = String::Handle(zone, String::ConcatAll(strings));

	return GetLibrarySourceByIndex(index, part_uri, patch);
	}

	static RawError* Compile(const Library& library, const Script& script) {
	bool update_lib_status = (script.kind() == RawScript::kScriptTag \|\|
	script.kind() == RawScript::kLibraryTag);
	if (update_lib_status) {
	library.SetLoadInProgress();
	}
	const Error& error = Error::Handle(Compiler::Compile(library, script));
	if (update_lib_status) {
	if (error.IsNull()) {
	library.SetLoaded();
	} else {
	// Compilation errors are not Dart instances, so just mark the library
	// as having failed to load without providing an error instance.
	library.SetLoadError(Object::null_instance());
	}
	}
	return error.raw();
	}

	static Dart_Handle LoadPartSource(Thread* thread,
	const Library& lib,
	const String& uri) {
	Zone* zone = thread->zone();
	const String& part_source =
	String::Handle(zone, GetLibrarySource(zone, lib, uri, false));
	const String& lib_uri = String::Handle(zone, lib.url());
	if (part_source.IsNull()) {
	return Api::NewError("Unable to read part file '%s' of library '%s'",
	uri.ToCString(), lib_uri.ToCString());
	}

	// Prepend the library URI to form a unique script URI for the part.
	const Array& strings = Array::Handle(zone, Array::New(3));
	strings.SetAt(0, lib_uri);
	strings.SetAt(1, Symbols::Slash());
	strings.SetAt(2, uri);
	const String& part_uri = String::Handle(zone, String::ConcatAll(strings));

	// Create a script object and compile the part.
	const Script& part_script = Script::Handle(
	zone, Script::New(part_uri, part_source, RawScript::kSourceTag));
	const Error& error = Error::Handle(zone, Compile(lib, part_script));
	return Api::NewHandle(thread, error.raw());
	}

	static Dart_Handle BootstrapLibraryTagHandler(Dart_LibraryTag tag,
	Dart_Handle library,
	Dart_Handle uri) {
	Thread* thread = Thread::Current();
	Zone* zone = thread->zone();
	// This handler calls into the VM directly and does not use the Dart
	// API so we transition back to VM.
	TransitionNativeToVM transition(thread);
	if (!Dart_IsLibrary(library)) {
	return Api::NewError("not a library");
	}
	if (!Dart_IsString(uri)) {
	return Api::NewError("uri is not a string");
	}
	if (tag == Dart_kCanonicalizeUrl) {
	// In the bootstrap loader we do not try and do any canonicalization.
	return uri;
	}
	const String& uri_str = Api::UnwrapStringHandle(zone, uri);
	ASSERT(!uri_str.IsNull());
	if (tag == Dart_kImportTag) {
	// We expect the core bootstrap libraries to only import other
	// core bootstrap libraries.
	// We have precreated all the bootstrap library objects hence
	// we do not expect to be called back with the tag set to kImportTag.
	// The bootstrap process explicitly loads all the libraries one by one.
	return Api::NewError("Invalid import of '%s' in a bootstrap library",
	uri_str.ToCString());
	}
	ASSERT(tag == Dart_kSourceTag);
	const Library& lib = Api::UnwrapLibraryHandle(zone, library);
	ASSERT(!lib.IsNull());
	return LoadPartSource(thread, lib, uri_str);
	}

	static RawError* LoadPatchFiles(Thread* thread,
	const Library& lib,
	intptr_t index) {
	const char** patch_files = bootstrap_libraries[index].patch_paths;
	if (patch_files == NULL) return Error::null();

	Zone* zone = thread->zone();
	String& patch_uri = String::Handle(
	zone, Symbols::New(thread, bootstrap_libraries[index].patch_uri));
	String& patch_file_uri = String::Handle(zone);
	String& source = String::Handle(zone);
	Script& script = Script::Handle(zone);
	Error& error = Error::Handle(zone);
	const Array& strings = Array::Handle(zone, Array::New(3));
	strings.SetAt(0, patch_uri);
	strings.SetAt(1, Symbols::Slash());
	for (intptr_t j = 0; patch_files[j] != NULL; j += kPathsEntryLength) {
	patch_file_uri = String::New(patch_files[j + kPathsUriOffset]);
	source = GetLibrarySourceByIndex(index, patch_file_uri, true);
	if (source.IsNull()) {
	const String& message = String::Handle(
	String::NewFormatted("Unable to find dart patch source for %s",
	patch_file_uri.ToCString()));
	return ApiError::New(message);
	}
	// Prepend the patch library URI to form a unique script URI for the patch.
	strings.SetAt(2, patch_file_uri);
	patch_file_uri = String::ConcatAll(strings);
	script = Script::New(patch_file_uri, source, RawScript::kPatchTag);
	error = lib.Patch(script);
	if (!error.IsNull()) {
	return error.raw();
	}
	}
	return Error::null();
	}

	static void Finish(Thread* thread) {
	Bootstrap::SetupNativeResolver();
	if (!ClassFinalizer::ProcessPendingClasses()) {
	FATAL("Error in class finalization during bootstrapping.");
	}

	// Eagerly compile the _Closure class as it is the class of all closure
	// instances. This allows us to just finalize function types without going
	// through the hoops of trying to compile their scope class.
	ObjectStore* object_store = thread->isolate()->object_store();
	Zone* zone = thread->zone();
	Class& cls = Class::Handle(zone, object_store->closure_class());
	Compiler::CompileClass(cls);

	#if defined(DEBUG)
	// Verify that closure field offsets are identical in Dart and C++.
	const Array& fields = Array::Handle(zone, cls.fields());
	ASSERT(fields.Length() == 6);
	Field& field = Field::Handle(zone);
	field ^= fields.At(0);
	ASSERT(field.Offset() == Closure::instantiator_type_arguments_offset());
	field ^= fields.At(1);
	ASSERT(field.Offset() == Closure::function_type_arguments_offset());
	field ^= fields.At(2);
	ASSERT(field.Offset() == Closure::delayed_type_arguments_offset());
	field ^= fields.At(3);
	ASSERT(field.Offset() == Closure::function_offset());
	field ^= fields.At(4);
	ASSERT(field.Offset() == Closure::context_offset());
	field ^= fields.At(5);
	ASSERT(field.Offset() == Closure::hash_offset());
	#endif // defined(DEBUG)

	// Eagerly compile Bool class, bool constants are used from within compiler.
	cls = object_store->bool_class();
	Compiler::CompileClass(cls);
	}

	static RawError* BootstrapFromSource(Thread* thread) {
	Isolate* isolate = thread->isolate();
	Zone* zone = thread->zone();
	String& uri = String::Handle(zone);
	String& source = String::Handle(zone);
	Script& script = Script::Handle(zone);
	Library& lib = Library::Handle(zone);
	Error& error = Error::Handle(zone);

	// Set the library tag handler for the isolate to the bootstrap
	// library tag handler so that we can load all the bootstrap libraries.
	Dart_LibraryTagHandler saved_tag_handler = isolate->library_tag_handler();
	isolate->set_library_tag_handler(BootstrapLibraryTagHandler);

	// Load, compile and patch bootstrap libraries.
	for (intptr_t i = 0; i < kBootstrapLibraryCount; ++i) {
	ObjectStore::BootstrapLibraryId id = bootstrap_libraries[i].index;
	uri = Symbols::New(thread, bootstrap_libraries[i].uri);
	lib = isolate->object_store()->bootstrap_library(id);
	ASSERT(!lib.IsNull());
	ASSERT(lib.raw() == Library::LookupLibrary(thread, uri));
	source = GetLibrarySourceByIndex(i, uri, false);
	if (source.IsNull()) {
	const String& message = String::Handle(String::NewFormatted(
	"Unable to find dart source for %s", uri.ToCString()));
	error ^= ApiError::New(message);
	break;
	}
	script = Script::New(uri, source, RawScript::kLibraryTag);
	error = Compile(lib, script);
	if (!error.IsNull()) {
	break;
	}
	// If a patch exists, load and patch the script.
	error = LoadPatchFiles(thread, lib, i);
	if (!error.IsNull()) {
	break;
	}
	}

	if (error.IsNull()) {
	Finish(thread);
	}
	// Restore the library tag handler for the isolate.
	isolate->set_library_tag_handler(saved_tag_handler);

	return error.raw();
	}

	#if !defined(DART_PRECOMPILED_RUNTIME)
	static RawError* BootstrapFromKernel(Thread* thread,
	const uint8_t* kernel_buffer,
	intptr_t kernel_buffer_size) {
	Zone* zone = thread->zone();
	const char* error = nullptr;
	kernel::Program* program = kernel::Program::ReadFromBuffer(
	kernel_buffer, kernel_buffer_size, &error);
	if (program == nullptr) {
	const intptr_t kMessageBufferSize = 512;
	char message_buffer[kMessageBufferSize];
	Utils::SNPrint(message_buffer, kMessageBufferSize,
	"Can't load Kernel binary: %s.", error);
	const String& msg = String::Handle(String::New(message_buffer, Heap::kOld));
	return ApiError::New(msg, Heap::kOld);
	}
	kernel::KernelLoader loader(program);
	Isolate* isolate = thread->isolate();

	// Load the bootstrap libraries in order (see object_store.h).
	Library& library = Library::Handle(zone);
	String& dart_name = String::Handle(zone);
	for (intptr_t i = 0; i < kBootstrapLibraryCount; ++i) {
	ObjectStore::BootstrapLibraryId id = bootstrap_libraries[i].index;
	library = isolate->object_store()->bootstrap_library(id);
	dart_name = library.url();
	for (intptr_t j = 0; j < program->library_count(); ++j) {
	const String& kernel_name = loader.LibraryUri(j);
	if (kernel_name.Equals(dart_name)) {
	loader.LoadLibrary(j);
	break;
	}
	}
	}

	// Finish bootstrapping, including class finalization.
	Finish(thread);

	// The platform binary may contain other libraries (e.g., dart:_builtin or
	// dart:io) that will not be bundled with application. Load them now.
	const Object& result = Object::Handle(zone, loader.LoadProgram());
	delete program;
	if (result.IsError()) {
	return Error::Cast(result).raw();
	}

	// The builtin library should be registered with the VM.
	dart_name = String::New("dart:_builtin");
	library = Library::LookupLibrary(thread, dart_name);
	isolate->object_store()->set_builtin_library(library);

	return Error::null();
	}
	#else
	static RawError* BootstrapFromKernel(Thread* thread,
	const uint8_t* kernel_buffer,
	intptr_t kernel_buffer_size) {
	UNREACHABLE();
	return Error::null();
	}
	#endif

	RawError* Bootstrap::DoBootstrapping(const uint8_t* kernel_buffer,
	intptr_t kernel_buffer_size) {
	Thread* thread = Thread::Current();
	Isolate* isolate = thread->isolate();
	Zone* zone = thread->zone();
	String& uri = String::Handle(zone);
	Library& lib = Library::Handle(zone);

	HANDLESCOPE(thread);

	// Ensure there are library objects for all the bootstrap libraries.
	for (intptr_t i = 0; i < kBootstrapLibraryCount; ++i) {
	ObjectStore::BootstrapLibraryId id = bootstrap_libraries[i].index;
	uri = Symbols::New(thread, bootstrap_libraries[i].uri);
	lib = isolate->object_store()->bootstrap_library(id);
	ASSERT(lib.raw() == Library::LookupLibrary(thread, uri));
	if (lib.IsNull()) {
	lib = Library::NewLibraryHelper(uri, false);
	lib.SetLoadRequested();
	lib.Register(thread);
	isolate->object_store()->set_bootstrap_library(id, lib);
	}
	}

	return (kernel_buffer == NULL)
	? BootstrapFromSource(thread)
	: BootstrapFromKernel(thread, kernel_buffer, kernel_buffer_size);
	}

	} // namespace dart