bootstrapper.cc.svn-base

Google浏览器V8内核代码

// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "v8.h"

#include "accessors.h"
#include "api.h"
#include "bootstrapper.h"
#include "compiler.h"
#include "debug.h"
#include "execution.h"
#include "global-handles.h"
#include "macro-assembler.h"
#include "natives.h"

namespace v8 { namespace internal {

// A SourceCodeCache uses a FixedArray to store pairs of
// (AsciiString*, JSFunction*), mapping names of native code files
// (runtime.js, etc.) to precompiled functions. Instead of mapping
// names to functions it might make sense to let the JS2C tool
// generate an index for each native JS file.
class SourceCodeCache BASE_EMBEDDED {
 public:
  explicit SourceCodeCache(ScriptType type): type_(type) { }

  void Initialize(bool create_heap_objects) {
    if (create_heap_objects) {
      cache_ = Heap::empty_fixed_array();
    } else {
      cache_ = NULL;
    }
  }

  void Iterate(ObjectVisitor* v) {
    v->VisitPointer(reinterpret_cast<Object**>(&cache_));
  }


  bool Lookup(Vector<const char> name, Handle<JSFunction>* handle) {
    for (int i = 0; i < cache_->length(); i+=2) {
      AsciiString* str = AsciiString::cast(cache_->get(i));
      if (str->IsEqualTo(name)) {
        *handle = Handle<JSFunction>(JSFunction::cast(cache_->get(i + 1)));
        return true;
      }
    }
    return false;
  }


  void Add(Vector<const char> name, Handle<JSFunction> fun) {
    ASSERT(fun->IsBoilerplate());
    HandleScope scope;
    int length = cache_->length();
    Handle<FixedArray> new_array =
        Factory::NewFixedArray(length + 2, TENURED);
    cache_->CopyTo(0, *new_array, 0, cache_->length());
    cache_ = *new_array;
    Handle<String> str = Factory::NewStringFromAscii(name, TENURED);
    cache_->set(length, *str);
    cache_->set(length + 1, *fun);
    Script::cast(fun->shared()->script())->set_type(Smi::FromInt(type_));
  }

 private:
  ScriptType type_;
  FixedArray* cache_;
  DISALLOW_COPY_AND_ASSIGN(SourceCodeCache);
};

static SourceCodeCache natives_cache(SCRIPT_TYPE_NATIVE);
static SourceCodeCache extensions_cache(SCRIPT_TYPE_EXTENSION);


Handle<String> Bootstrapper::NativesSourceLookup(int index) {
  ASSERT(0 <= index && index < Natives::GetBuiltinsCount());
  if (Heap::natives_source_cache()->get(index)->IsUndefined()) {
    Handle<String> source_code =
      Factory::NewStringFromAscii(Natives::GetScriptSource(index));
    Heap::natives_source_cache()->set(index, *source_code);
  }
  Handle<Object> cached_source(Heap::natives_source_cache()->get(index));
  return Handle<String>::cast(cached_source);
}


bool Bootstrapper::NativesCacheLookup(Vector<const char> name,
                                      Handle<JSFunction>* handle) {
  return natives_cache.Lookup(name, handle);
}


void Bootstrapper::NativesCacheAdd(Vector<const char> name,
                                   Handle<JSFunction> fun) {
  natives_cache.Add(name, fun);
}


void Bootstrapper::Initialize(bool create_heap_objects) {
  natives_cache.Initialize(create_heap_objects);
  extensions_cache.Initialize(create_heap_objects);
}


void Bootstrapper::TearDown() {
  natives_cache.Initialize(false);  // Yes, symmetrical
  extensions_cache.Initialize(false);
}


// Pending fixups are code positions that have refer to builtin code
// objects that were not available at the time the code was generated.
// The pending list is processed whenever an environment has been
// created.
class PendingFixups : public AllStatic {
 public:
  static void Add(Code* code, MacroAssembler* masm);
  static bool Process(Handle<JSBuiltinsObject> builtins);

  static void Iterate(ObjectVisitor* v);

 private:
  static List<Object*> code_;
  static List<const char*> name_;
  static List<int> pc_;
  static List<uint32_t> flags_;

  static void Clear();
};


List<Object*> PendingFixups::code_(0);
List<const char*> PendingFixups::name_(0);
List<int> PendingFixups::pc_(0);
List<uint32_t> PendingFixups::flags_(0);


void PendingFixups::Add(Code* code, MacroAssembler* masm) {
  // Note this code is not only called during bootstrapping.
  List<MacroAssembler::Unresolved>* unresolved = masm->unresolved();
  int n = unresolved->length();
  for (int i = 0; i < n; i++) {
    const char* name = unresolved->at(i).name;
    code_.Add(code);
    name_.Add(name);
    pc_.Add(unresolved->at(i).pc);
    flags_.Add(unresolved->at(i).flags);
    LOG(StringEvent("unresolved", name));
  }
}


bool PendingFixups::Process(Handle<JSBuiltinsObject> builtins) {
  HandleScope scope;
  // NOTE: Extra fixups may be added to the list during the iteration
  // due to lazy compilation of functions during the processing. Do not
  // cache the result of getting the length of the code list.
  for (int i = 0; i < code_.length(); i++) {
    const char* name = name_[i];
    uint32_t flags = flags_[i];
    Handle<String> symbol = Factory::LookupAsciiSymbol(name);
    Object* o = builtins->GetProperty(*symbol);
#ifdef DEBUG
    if (!o->IsJSFunction()) {
      V8_Fatal(__FILE__, __LINE__, "Cannot resolve call to builtin %s", name);
    }
#endif
    Handle<JSFunction> f = Handle<JSFunction>(JSFunction::cast(o));
    // Make sure the number of parameters match the formal parameter count.
    int argc = Bootstrapper::FixupFlagsArgumentsCount::decode(flags);
    USE(argc);
    ASSERT(f->shared()->formal_parameter_count() == argc);
    if (!f->is_compiled()) {
      // Do lazy compilation and check for stack overflows.
      if (!CompileLazy(f, CLEAR_EXCEPTION)) {
        Clear();
        return false;
      }
    }
    Code* code = Code::cast(code_[i]);
    Address pc = code->instruction_start() + pc_[i];
    bool is_pc_relative = Bootstrapper::FixupFlagsIsPCRelative::decode(flags);
    if (is_pc_relative) {
      Assembler::set_target_address_at(pc, f->code()->instruction_start());
    } else {
      *reinterpret_cast<Object**>(pc) = f->code();
    }
    LOG(StringEvent("resolved", name));
  }
  Clear();

  // TODO(1240818): We should probably try to avoid doing this for all
  // the V8 builtin JS files. It should only happen after running
  // runtime.js - just like there shouldn't be any fixups left after
  // that.
  for (int i = 0; i < Builtins::NumberOfJavaScriptBuiltins(); i++) {
    Builtins::JavaScript id = static_cast<Builtins::JavaScript>(i);
    Handle<String> name = Factory::LookupAsciiSymbol(Builtins::GetName(id));
    JSFunction* function = JSFunction::cast(builtins->GetProperty(*name));
    builtins->set_javascript_builtin(id, function);
  }

  return true;
}


void PendingFixups::Clear() {
  code_.Clear();
  name_.Clear();
  pc_.Clear();
  flags_.Clear();
}


void PendingFixups::Iterate(ObjectVisitor* v) {
  if (!code_.is_empty()) {
    v->VisitPointers(&code_[0], &code_[0] + code_.length());
  }
}


class Genesis BASE_EMBEDDED {
 public:
  Genesis(Handle<Object> global_object,
          v8::Handle<v8::ObjectTemplate> global_template,
          v8::ExtensionConfiguration* extensions);
  ~Genesis();

  Handle<Context> result() { return result_; }

  Genesis* previous() { return previous_; }
  static Genesis* current() { return current_; }

 private:
  Handle<Context> global_context_;

  // There may be more than one active genesis object: When GC is
  // triggered during environment creation there may be weak handle
  // processing callbacks which may create new environments.
  Genesis* previous_;
  static Genesis* current_;

  Handle<Context> global_context() { return global_context_; }

  void CreateRoots(v8::Handle<v8::ObjectTemplate> global_template,
                   Handle<Object> global_object);
  void InstallNativeFunctions();
  bool InstallNatives();
  bool InstallExtensions(v8::ExtensionConfiguration* extensions);
  bool InstallExtension(const char* name);
  bool InstallExtension(v8::RegisteredExtension* current);
  bool InstallSpecialObjects();
  bool ConfigureGlobalObject(v8::Handle<v8::ObjectTemplate> global_template);

  // Migrates all properties from the 'from' object to the 'to'
  // object and overrides the prototype in 'to' with the one from
  // 'from'.
  void TransferObject(Handle<JSObject> from, Handle<JSObject> to);
  void TransferNamedProperties(Handle<JSObject> from, Handle<JSObject> to);
  void TransferIndexedProperties(Handle<JSObject> from, Handle<JSObject> to);

  Handle<DescriptorArray> ComputeFunctionInstanceDescriptor(
      bool make_prototype_read_only,
      bool make_prototype_enumerable = false);
  void MakeFunctionInstancePrototypeWritable();

  void AddSpecialFunction(Handle<JSObject> prototype,
                          const char* name,
                          Handle<Code> code);

  void BuildSpecialFunctionTable();

  static bool CompileBuiltin(int index);
  static bool CompileNative(Vector<const char> name, Handle<String> source);
  static bool CompileScriptCached(Vector<const char> name,
                                  Handle<String> source,
                                  SourceCodeCache* cache,
                                  v8::Extension* extension,
                                  bool use_runtime_context);

  Handle<Context> result_;
};

Genesis* Genesis::current_ = NULL;


void Bootstrapper::Iterate(ObjectVisitor* v) {
  natives_cache.Iterate(v);
  extensions_cache.Iterate(v);
  PendingFixups::Iterate(v);
}


// While setting up the environment, we collect code positions that
// need to be patched before we can run any code in the environment.
void Bootstrapper::AddFixup(Code* code, MacroAssembler* masm) {
  PendingFixups::Add(code, masm);
}


bool Bootstrapper::IsActive() {
  return Genesis::current() != NULL;
}


Handle<Context> Bootstrapper::CreateEnvironment(
    Handle<Object> global_object,
    v8::Handle<v8::ObjectTemplate> global_template,
    v8::ExtensionConfiguration* extensions) {
  Genesis genesis(global_object, global_template, extensions);
  return genesis.result();