// 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 <memory>
#include <utility>

#include "include/dart_api.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/longjump.h"
#include "vm/object.h"
#include "vm/object_store.h"
#include "vm/symbols.h"

namespace dart {

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

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

#if !defined(DART_PRECOMPILED_RUNTIME)
#define MAKE_PROPERTIES(CamelName, name)                                       \
  {ObjectStore::k##CamelName, "dart:" #name},

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

#undef MAKE_PROPERTIES

static constexpr intptr_t kBootstrapLibraryCount =
    ARRAY_SIZE(bootstrap_libraries);
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_group()->object_store();
  Zone* zone = thread->zone();
  Class& cls = Class::Handle(zone, object_store->closure_class());
  cls.EnsureIsFinalized(thread);

  // Make sure _Closure fields are not marked as unboxed as they are accessed
  // with plain loads.
  const Array& fields = Array::Handle(zone, cls.fields());
  Field& field = Field::Handle(zone);
  for (intptr_t i = 0; i < fields.Length(); ++i) {
    field ^= fields.At(i);
    field.set_is_unboxed(false);
  }
  // _Closure._hash field should be explicitly marked as nullable because
  // VM creates instances of _Closure without compiling its constructors,
  // so it won't get nullability info from a constructor.
  field ^= fields.At(fields.Length() - 1);
  // Note that UserVisibleName depends on --show-internal-names.
  ASSERT(strncmp(field.UserVisibleNameCString(), "_hash", 5) == 0);
  field.RecordStore(Object::null_object());

#if defined(DEBUG)
  // Verify that closure field offsets are identical in Dart and C++.
  ASSERT_EQUAL(fields.Length(), 6);
  field ^= fields.At(0);
  ASSERT_EQUAL(field.HostOffset(),
               Closure::instantiator_type_arguments_offset());
  field ^= fields.At(1);
  ASSERT_EQUAL(field.HostOffset(), Closure::function_type_arguments_offset());
  field ^= fields.At(2);
  ASSERT_EQUAL(field.HostOffset(), Closure::delayed_type_arguments_offset());
  field ^= fields.At(3);
  ASSERT_EQUAL(field.HostOffset(), Closure::function_offset());
  field ^= fields.At(4);
  ASSERT_EQUAL(field.HostOffset(), Closure::context_offset());
  field ^= fields.At(5);
  ASSERT_EQUAL(field.HostOffset(), Closure::hash_offset());
#endif  // defined(DEBUG)

  // Eagerly compile to avoid repeated checks when loading constants or
  // serializing.
  cls = object_store->null_class();
  cls.EnsureIsFinalized(thread);
  cls = object_store->bool_class();
  cls.EnsureIsFinalized(thread);
  cls = object_store->array_class();
  cls.EnsureIsFinalized(thread);
  cls = object_store->immutable_array_class();
  cls.EnsureIsFinalized(thread);
  cls = object_store->map_impl_class();
  cls.EnsureIsFinalized(thread);
  cls = object_store->const_map_impl_class();
  cls.EnsureIsFinalized(thread);
  cls = object_store->set_impl_class();
  cls.EnsureIsFinalized(thread);
  cls = object_store->const_set_impl_class();
  cls.EnsureIsFinalized(thread);
}

static ErrorPtr BootstrapFromKernelSingleProgram(
    Thread* thread,
    std::unique_ptr<kernel::Program> program) {
  Zone* zone = thread->zone();
  LongJumpScope jump;
  if (setjmp(*jump.Set()) == 0) {
    kernel::KernelLoader loader(program.get(), /*uri_to_source_table=*/nullptr);

    auto isolate_group = thread->isolate_group();

    if (isolate_group->obfuscate()) {
      loader.ReadObfuscationProhibitions();
    }

    // Load the bootstrap libraries in order (see object_store.h).
    Library& library = Library::Handle(zone);
    for (intptr_t i = 0; i < kBootstrapLibraryCount; ++i) {
      ObjectStore::BootstrapLibraryId id = bootstrap_libraries[i].index;
      library = isolate_group->object_store()->bootstrap_library(id);
      loader.LoadLibrary(library);
    }

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

    isolate_group->object_store()->InitKnownObjects();

    // 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());
    program.reset();
    if (result.IsError()) {
      return Error::Cast(result).ptr();
    }

    if (FLAG_precompiled_mode) {
      loader.ReadLoadingUnits();
    }

    return Error::null();
  }

  // Either class finalization failed or we caught a compile-time error.
  // In both cases sticky error would be set.
  return Thread::Current()->StealStickyError();
}

static ErrorPtr BootstrapFromKernel(Thread* thread,
                                    const uint8_t* kernel_buffer,
                                    intptr_t kernel_buffer_size) {
  Zone* zone = thread->zone();
  const char* error = nullptr;
  std::unique_ptr<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);
  }

  if (program->is_single_program()) {
    return BootstrapFromKernelSingleProgram(thread, std::move(program));
  }

  GrowableArray<intptr_t> subprogram_file_starts;
  {
    kernel::Reader reader(program->binary());
    kernel::KernelLoader::index_programs(&reader, &subprogram_file_starts);
  }
  intptr_t subprogram_count = subprogram_file_starts.length() - 1;

  // Create "fake programs" for each sub-program.
  auto& load_result = Error::Handle(zone);
  for (intptr_t i = 0; i < subprogram_count; i++) {
    intptr_t subprogram_start = subprogram_file_starts.At(i);
    intptr_t subprogram_end = subprogram_file_starts.At(i + 1);
    const auto& component = TypedDataBase::Handle(
        program->binary().ViewFromTo(subprogram_start, subprogram_end));
    kernel::Reader reader(component);
    const char* error = nullptr;
    std::unique_ptr<kernel::Program> subprogram =
        kernel::Program::ReadFrom(&reader, &error);
    if (subprogram == nullptr) {
      FATAL("Failed to load kernel file: %s", error);
    }
    ASSERT(subprogram->is_single_program());
    if (i == 0) {
      // The first subprogram must be the main Dart program.
      load_result ^=
          BootstrapFromKernelSingleProgram(thread, std::move(subprogram));
    } else {
      // Restrictions on the subsequent programs: Must contain only
      // contain dummy libraries with VM recognized classes (or classes kept
      // fully intact by tree-shaking).
      // Currently only used for concatenating native assets mappings.
      kernel::KernelLoader loader(subprogram.get(),
                                  /*uri_to_source_table=*/nullptr);
      load_result ^= loader.LoadProgram(false);
    }
    if (load_result.IsError()) return load_result.ptr();
  }
  return Error::null();
}

ErrorPtr Bootstrap::DoBootstrapping(const uint8_t* kernel_buffer,
                                    intptr_t kernel_buffer_size) {
  Thread* thread = Thread::Current();
  auto isolate_group = thread->isolate_group();
  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_group->object_store()->bootstrap_library(id);
    ASSERT(lib.ptr() == Library::LookupLibrary(thread, uri));
    if (lib.IsNull()) {
      lib = Library::NewLibraryHelper(uri, false);
      lib.SetLoadRequested();
      lib.Register(thread);
      isolate_group->object_store()->set_bootstrap_library(id, lib);
    }
  }

  return BootstrapFromKernel(thread, kernel_buffer, kernel_buffer_size);
}
#else
ErrorPtr Bootstrap::DoBootstrapping(const uint8_t* kernel_buffer,
                                    intptr_t kernel_buffer_size) {
  UNREACHABLE();
  return Error::null();
}
#endif

}  // namespace dart