CSE2410 Fall 2014 Bounce

// 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.

#ifndef V8_V8_DEBUG_H_

#define V8_V8_DEBUG_H_

#include "../include/v8-debug.h"

#include "assembler.h"

#include "code-stubs.h"

#include "debug-agent.h"

#include "execution.h"

#include "factory.h"

#include "platform.h"

#include "string-stream.h"

#include "v8threads.h"

namespace v8 { namespace internal {

// Forward declarations.

class EnterDebugger;

// Step actions. NOTE: These values are in macros.py as well.

enum StepAction {

  StepNone = -1,  // Stepping not prepared.

  StepOut = 0,   // Step out of the current function.

  StepNext = 1,  // Step to the next statement in the current function.

  StepIn = 2,    // Step into new functions invoked or the next statement

                 // in the current function.

  StepMin = 3,   // Perform a minimum step in the current function.

  StepInMin = 4  // Step into new functions invoked or perform a minimum step

                 // in the current function.

};

// Type of exception break. NOTE: These values are in macros.py as well.

enum ExceptionBreakType {

  BreakException = 0,

  BreakUncaughtException = 1

};

// Type of exception break. NOTE: These values are in macros.py as well.

enum BreakLocatorType {

  ALL_BREAK_LOCATIONS = 0,

  SOURCE_BREAK_LOCATIONS = 1

};

// Class for iterating through the break points in a function and changing

// them.

class BreakLocationIterator {

 public:

  explicit BreakLocationIterator(Handle<DebugInfo> debug_info,

                                 BreakLocatorType type);

  virtual ~BreakLocationIterator();

  void Next();

  void Next(int count);

  void FindBreakLocationFromAddress(Address pc);

  void FindBreakLocationFromPosition(int position);

  void Reset();

  bool Done() const;

  void SetBreakPoint(Handle<Object> break_point_object);

  void ClearBreakPoint(Handle<Object> break_point_object);

  void SetOneShot();

  void ClearOneShot();

  void PrepareStepIn();

  bool IsExit() const;

  bool HasBreakPoint();

  bool IsDebugBreak();

  Object* BreakPointObjects();

  void ClearAllDebugBreak();

  inline int code_position() { return pc() - debug_info_->code()->entry(); }

  inline int break_point() { return break_point_; }

  inline int position() { return position_; }

  inline int statement_position() { return statement_position_; }

  inline Address pc() { return reloc_iterator_->rinfo()->pc(); }

  inline Code* code() { return debug_info_->code(); }

  inline RelocInfo* rinfo() { return reloc_iterator_->rinfo(); }

  inline RelocInfo::Mode rmode() const {

    return reloc_iterator_->rinfo()->rmode();

  }

  inline RelocInfo* original_rinfo() {

    return reloc_iterator_original_->rinfo();

  }

  inline RelocInfo::Mode original_rmode() const {

    return reloc_iterator_original_->rinfo()->rmode();

  }

 protected:

  bool RinfoDone() const;

  void RinfoNext();

  BreakLocatorType type_;

  int break_point_;

  int position_;

  int statement_position_;

  Handle<DebugInfo> debug_info_;

  RelocIterator* reloc_iterator_;

  RelocIterator* reloc_iterator_original_;

 private:

  void SetDebugBreak();

  void ClearDebugBreak();

  bool IsDebugBreakAtReturn();

  void SetDebugBreakAtReturn();

  void ClearDebugBreakAtReturn();

  DISALLOW_COPY_AND_ASSIGN(BreakLocationIterator);

};

// Linked list holding debug info objects. The debug info objects are kept as

// weak handles to avoid a debug info object to keep a function alive.

class DebugInfoListNode {

 public:

  explicit DebugInfoListNode(DebugInfo* debug_info);

  virtual ~DebugInfoListNode();

  DebugInfoListNode* next() { return next_; }

  void set_next(DebugInfoListNode* next) { next_ = next; }

  Handle<DebugInfo> debug_info() { return debug_info_; }

 private:

  // Global (weak) handle to the debug info object.

  Handle<DebugInfo> debug_info_;

  // Next pointer for linked list.

  DebugInfoListNode* next_;

};

// This class contains the debugger support. The main purpose is to handle

// setting break points in the code.

//

// This class controls the debug info for all functions which currently have

// active breakpoints in them. This debug info is held in the heap root object

// debug_info which is a FixedArray. Each entry in this list is of class

// DebugInfo.

class Debug {

 public:

  static void Setup(bool create_heap_objects);

  static bool Load();

  static void Unload();

  static bool IsLoaded() { return !debug_context_.is_null(); }

  static bool InDebugger() { return thread_local_.debugger_entry_ != NULL; }

  static void PreemptionWhileInDebugger();

  static void Iterate(ObjectVisitor* v);

  static Object* Break(Arguments args);

  static void SetBreakPoint(Handle<SharedFunctionInfo> shared,

                            int source_position,

                            Handle<Object> break_point_object);

  static void ClearBreakPoint(Handle<Object> break_point_object);

  static void ClearAllBreakPoints();

  static void FloodWithOneShot(Handle<SharedFunctionInfo> shared);

  static void FloodHandlerWithOneShot();

  static void ChangeBreakOnException(ExceptionBreakType type, bool enable);

  static void PrepareStep(StepAction step_action, int step_count);

  static void ClearStepping();

  static bool StepNextContinue(BreakLocationIterator* break_location_iterator,

                               JavaScriptFrame* frame);

  static Handle<DebugInfo> GetDebugInfo(Handle<SharedFunctionInfo> shared);

  static bool HasDebugInfo(Handle<SharedFunctionInfo> shared);

  // Returns whether the operation succeeded.

  static bool EnsureDebugInfo(Handle<SharedFunctionInfo> shared);

  static bool IsDebugBreak(Address addr);

  static bool IsDebugBreakAtReturn(RelocInfo* rinfo);

  // Check whether a code stub with the specified major key is a possible break

  // point location.

  static bool IsSourceBreakStub(Code* code);

  static bool IsBreakStub(Code* code);

  // Find the builtin to use for invoking the debug break

  static Handle<Code> FindDebugBreak(RelocInfo* rinfo);

  static Handle<Object> GetSourceBreakLocations(

      Handle<SharedFunctionInfo> shared);

  // Getter for the debug_context.

  inline static Handle<Context> debug_context() { return debug_context_; }

  // Check whether a global object is the debug global object.

  static bool IsDebugGlobal(GlobalObject* global);

  // Fast check to see if any break points are active.

  inline static bool has_break_points() { return has_break_points_; }

  static void NewBreak(StackFrame::Id break_frame_id);

  static void SetBreak(StackFrame::Id break_frame_id, int break_id);

  static StackFrame::Id break_frame_id() {

    return thread_local_.break_frame_id_;

  }

  static int break_id() { return thread_local_.break_id_; }

  static bool StepInActive() { return thread_local_.step_into_fp_ != 0; }

  static void HandleStepIn(Handle<JSFunction> function,

                           Address fp,

                           bool is_constructor);

  static Address step_in_fp() { return thread_local_.step_into_fp_; }

  static Address* step_in_fp_addr() { return &thread_local_.step_into_fp_; }

  static EnterDebugger* debugger_entry() {

    return thread_local_.debugger_entry_;

  }

  static void set_debugger_entry(EnterDebugger* entry) {

    thread_local_.debugger_entry_ = entry;

  }

  static bool preemption_pending() {

    return thread_local_.preemption_pending_;

  }

  static void set_preemption_pending(bool preemption_pending) {

    thread_local_.preemption_pending_ = preemption_pending;

  }

  // Getter and setter for the disable break state.

  static bool disable_break() { return disable_break_; }

  static void set_disable_break(bool disable_break) {

    disable_break_ = disable_break;

  }

  // Getters for the current exception break state.

  static bool break_on_exception() { return break_on_exception_; }

  static bool break_on_uncaught_exception() {

    return break_on_uncaught_exception_;

  }

  enum AddressId {

    k_after_break_target_address,

    k_debug_break_return_address,

    k_register_address

  };

  // Support for setting the address to jump to when returning from break point.

  static Address* after_break_target_address() {

    return reinterpret_cast<Address*>(&thread_local_.after_break_target_);

  }

  // Support for saving/restoring registers when handling debug break calls.

  static Object** register_address(int r) {

    return &registers_[r];

  }

  // Address of the debug break return entry code.

  static Code* debug_break_return_entry() { return debug_break_return_entry_; }

  // Support for getting the address of the debug break on return code.

  static Code** debug_break_return_address() {

    return &debug_break_return_;

  }

  static const int kEstimatedNofDebugInfoEntries = 16;

  static const int kEstimatedNofBreakPointsInFunction = 16;

  static void HandleWeakDebugInfo(v8::Persistent<v8::Value> obj, void* data);

  friend class Debugger;

  friend Handle<FixedArray> GetDebuggedFunctions();  // In test-debug.cc

  friend void CheckDebuggerUnloaded(bool check_functions);  // In test-debug.cc

  // Threading support.

  static char* ArchiveDebug(char* to);

  static char* RestoreDebug(char* from);

  static int ArchiveSpacePerThread();

  // Mirror cache handling.

  static void ClearMirrorCache();

  // Code generation assumptions.

  static const int kIa32CallInstructionLength = 5;

  static const int kIa32JSReturnSequenceLength = 6;

  // Code generator routines.

  static void GenerateLoadICDebugBreak(MacroAssembler* masm);

  static void GenerateStoreICDebugBreak(MacroAssembler* masm);

  static void GenerateKeyedLoadICDebugBreak(MacroAssembler* masm);

  static void GenerateKeyedStoreICDebugBreak(MacroAssembler* masm);

  static void GenerateConstructCallDebugBreak(MacroAssembler* masm);

  static void GenerateReturnDebugBreak(MacroAssembler* masm);

  static void GenerateReturnDebugBreakEntry(MacroAssembler* masm);

  static void GenerateStubNoRegistersDebugBreak(MacroAssembler* masm);

  // Called from stub-cache.cc.

  static void GenerateCallICDebugBreak(MacroAssembler* masm);

 private:

  static bool CompileDebuggerScript(int index);

  static void ClearOneShot();

  static void ActivateStepIn(StackFrame* frame);

  static void ClearStepIn();

  static void ClearStepNext();

  // Returns whether the compile succeeded.

  static bool EnsureCompiled(Handle<SharedFunctionInfo> shared);

  static void RemoveDebugInfo(Handle<DebugInfo> debug_info);

  static void SetAfterBreakTarget(JavaScriptFrame* frame);

  static Handle<Object> CheckBreakPoints(Handle<Object> break_point);

  static bool CheckBreakPoint(Handle<Object> break_point_object);

  // Global handle to debug context where all the debugger JavaScript code is

  // loaded.

  static Handle<Context> debug_context_;

  // Boolean state indicating whether any break points are set.

  static bool has_break_points_;

  static DebugInfoListNode* debug_info_list_;

  static bool disable_break_;

  static bool break_on_exception_;

  static bool break_on_uncaught_exception_;

  // Per-thread data.

  class ThreadLocal {

   public:

    // Counter for generating next break id.

    int break_count_;

    // Current break id.

    int break_id_;

    // Frame id for the frame of the current break.

    StackFrame::Id break_frame_id_;

    // Step action for last step performed.

    StepAction last_step_action_;

    // Source statement position from last step next action.

    int last_statement_position_;

    // Number of steps left to perform before debug event.

    int step_count_;

    // Frame pointer from last step next action.

    Address last_fp_;

    // Frame pointer for frame from which step in was performed.

    Address step_into_fp_;

    // Storage location for jump when exiting debug break calls.

    Address after_break_target_;

    // Top debugger entry.

    EnterDebugger* debugger_entry_;

    // Preemption happened while debugging.

    bool preemption_pending_;

  };

  // Storage location for registers when handling debug break calls

  static JSCallerSavedBuffer registers_;

  static ThreadLocal thread_local_;

  static void ThreadInit();

  // Code object for debug break return entry code.

  static Code* debug_break_return_entry_;

  // Code to call for handling debug break on return.

  static Code* debug_break_return_;

  DISALLOW_COPY_AND_ASSIGN(Debug);

};

// A Queue of Vector<uint16_t> objects.  A thread-safe version is

// LockingMessageQueue, based on this class.

class MessageQueue BASE_EMBEDDED {

 public:

  explicit MessageQueue(int size);

  ~MessageQueue();

  bool IsEmpty() const { return start_ == end_; }

  Vector<uint16_t> Get();

  void Put(const Vector<uint16_t>& message);

  void Clear() { start_ = end_ = 0; }  // Queue is empty after Clear().

 private:

  // Doubles the size of the message queue, and copies the messages.

  void Expand();

  Vector<uint16_t>* messages_;

  int start_;

  int end_;

  int size_;  // The size of the queue buffer.  Queue can hold size-1 messages.

};

// LockingMessageQueue is a thread-safe circular buffer of Vector<uint16_t>

// messages.  The message data is not managed by LockingMessageQueue.

// Pointers to the data are passed in and out. Implemented by adding a

// Mutex to MessageQueue.  Includes logging of all puts and gets.

class LockingMessageQueue BASE_EMBEDDED {

 public:

  explicit LockingMessageQueue(int size);

  ~LockingMessageQueue();

  bool IsEmpty() const;

  Vector<uint16_t> Get();

  void Put(const Vector<uint16_t>& message);

  void Clear();

 private:

  MessageQueue queue_;

  Mutex* lock_;

  DISALLOW_COPY_AND_ASSIGN(LockingMessageQueue);

};

class DebugMessageThread;

class Debugger {

 public:

  static void DebugRequest(const uint16_t* json_request, int length);

  static Handle<Object> MakeJSObject(Vector<const char> constructor_name,

                                     int argc, Object*** argv,

                                     bool* caught_exception);

  static Handle<Object> MakeExecutionState(bool* caught_exception);

  static Handle<Object> MakeBreakEvent(Handle<Object> exec_state,

                                       Handle<Object> break_points_hit,

                                       bool* caught_exception);

  static Handle<Object> MakeExceptionEvent(Handle<Object> exec_state,

                                           Handle<Object> exception,

                                           bool uncaught,

                                           bool* caught_exception);

  static Handle<Object> MakeNewFunctionEvent(Handle<Object> func,

                                             bool* caught_exception);

  static Handle<Object> MakeCompileEvent(Handle<Script> script,

                                         bool before,

                                         bool* caught_exception);

  static void OnDebugBreak(Handle<Object> break_points_hit, bool auto_continue);

  static void OnException(Handle<Object> exception, bool uncaught);

  static void OnBeforeCompile(Handle<Script> script);

  static void OnAfterCompile(Handle<Script> script,

                           Handle<JSFunction> fun);

  static void OnNewFunction(Handle<JSFunction> fun);

  static void ProcessDebugEvent(v8::DebugEvent event,

                                Handle<Object> event_data,

                                bool auto_continue);

  static void NotifyMessageHandler(v8::DebugEvent event,

                                   Handle<Object> exec_state,

                                   Handle<Object> event_data,

                                   bool auto_continue);

  static void SetEventListener(Handle<Object> callback, Handle<Object> data);

  static void SetMessageHandler(v8::DebugMessageHandler handler, void* data,

                                bool message_handler_thread);

  static void TearDown();

  static void SetHostDispatchHandler(v8::DebugHostDispatchHandler handler,

                                     void* data);

  // Invoke the message handler function.

  static void InvokeMessageHandler(Vector< uint16_t> message);

  // Send a message to the message handler eiher through the message thread or

  // directly.

  static void SendMessage(Vector<uint16_t> message);

  // Send the JSON message for a debug event.

  static bool SendEventMessage(Handle<Object> event_data);

  // Add a debugger command to the command queue.

  static void ProcessCommand(Vector<const uint16_t> command);

  // Check whether there are commands in the command queue.

  static bool HasCommands();

  static void ProcessHostDispatch(void* dispatch);

  static Handle<Object> Call(Handle<JSFunction> fun,

                             Handle<Object> data,

                             bool* pending_exception);

  // Start the debugger agent listening on the provided port.

  static bool StartAgent(const char* name, int port);

  // Stop the debugger agent.

  static void StopAgent();

  // Unload the debugger if possible. Only called when no debugger is currently

  // active.

  static void UnloadDebugger();

  inline static bool EventActive(v8::DebugEvent event) {

    ScopedLock with(debugger_access_);

    // Check whether the message handler was been cleared.

    if (message_handler_cleared_) {

      UnloadDebugger();

    }

    // Currently argument event is not used.

    return !compiling_natives_ && Debugger::IsDebuggerActive();

  }

  static void set_compiling_natives(bool compiling_natives) {

    Debugger::compiling_natives_ = compiling_natives;

  }

  static bool compiling_natives() { return Debugger::compiling_natives_; }

  static void set_loading_debugger(bool v) { is_loading_debugger_ = v; }

  static bool is_loading_debugger() { return Debugger::is_loading_debugger_; }

 private:

  static bool IsDebuggerActive();

  static Mutex* debugger_access_;  // Mutex guarding debugger variables.

  static Handle<Object> event_listener_;  // Global handle to listener.

  static Handle<Object> event_listener_data_;

  static bool compiling_natives_;  // Are we compiling natives?

  static bool is_loading_debugger_;  // Are we loading the debugger?

  static bool never_unload_debugger_;  // Can we unload the debugger?

  static DebugMessageThread* message_thread_;

  static v8::DebugMessageHandler message_handler_;

  static bool message_handler_cleared_;  // Was message handler cleared?

  static void* message_handler_data_;

  static v8::DebugHostDispatchHandler host_dispatch_handler_;

  static void* host_dispatch_handler_data_;

  static DebuggerAgent* agent_;

  static const int kQueueInitialSize = 4;

  static LockingMessageQueue command_queue_;

  static LockingMessageQueue message_queue_;

  static Semaphore* command_received_;  // Signaled for each command received.

  static Semaphore* message_received_;  // Signalled for each message send.

  friend class EnterDebugger;

  friend class DebugMessageThread;

};

// Thread to read messages from the message queue and invoke the debug message

// handler in another thread as the V8 thread. This thread is started if the

// registration of the debug message handler requested to be called in a thread

// seperate from the V8 thread.

class DebugMessageThread: public Thread {

 public:

  DebugMessageThread() : keep_running_(true) {}

  virtual ~DebugMessageThread() {}

  // Main function of DebugMessageThread thread.

  void Run();

  void Stop();

 private:

  bool keep_running_;

  DISALLOW_COPY_AND_ASSIGN(DebugMessageThread);

};

// This class is used for entering the debugger. Create an instance in the stack

// to enter the debugger. This will set the current break state, make sure the

// debugger is loaded and switch to the debugger context. If the debugger for

// some reason could not be entered FailedToEnter will return true.

class EnterDebugger BASE_EMBEDDED {

 public:

  EnterDebugger()

      : prev_(Debug::debugger_entry()),

        has_js_frames_(!it_.done()) {

    ASSERT(prev_ == NULL ? !Debug::preemption_pending() : true);

    // Link recursive debugger entry.

    Debug::set_debugger_entry(this);

    // Store the previous break id and frame id.

    break_id_ = Debug::break_id();

    break_frame_id_ = Debug::break_frame_id();

    // Create the new break info. If there is no JavaScript frames there is no

    // break frame id.

    if (has_js_frames_) {

      Debug::NewBreak(it_.frame()->id());

    } else {

      Debug::NewBreak(StackFrame::NO_ID);

    }

    // Make sure that debugger is loaded and enter the debugger context.

    load_failed_ = !Debug::Load();

    if (!load_failed_) {

      // NOTE the member variable save which saves the previous context before

      // this change.

      Top::set_context(*Debug::debug_context());

    }

  }

  ~EnterDebugger() {

    // Restore to the previous break state.

    Debug::SetBreak(break_frame_id_, break_id_);

    // Request preemption when leaving the last debugger entry and a preemption

    // had been recorded while debugging. This is to avoid starvation in some

    // debugging scenarios.

    if (prev_ == NULL && Debug::preemption_pending()) {

      StackGuard::Preempt();

      Debug::set_preemption_pending(false);

    }

    // If there are commands in the queue when leaving the debugger request that

    // these commands are processed.

    if (prev_ == NULL && Debugger::HasCommands()) {

      StackGuard::DebugCommand();

    }

    // If leaving the debugger with the debugger no longer active unload it.

    if (prev_ == NULL) {

      if (!Debugger::IsDebuggerActive()) {

        Debugger::UnloadDebugger();

      }

    }

    // Leaving this debugger entry.

    Debug::set_debugger_entry(prev_);

  }

  // Check whether the debugger could be entered.

  inline bool FailedToEnter() { return load_failed_; }

  // Check whether there are any JavaScript frames on the stack.

  inline bool HasJavaScriptFrames() { return has_js_frames_; }

 private:

  EnterDebugger* prev_;  // Previous debugger entry if entered recursively.

  JavaScriptFrameIterator it_;

  const bool has_js_frames_;  // Were there any JavaScript frames?

  StackFrame::Id break_frame_id_;  // Previous break frame id.

  int break_id_;  // Previous break id.

  bool load_failed_;  // Did the debugger fail to load?

  SaveContext save_;  // Saves previous context.

};

// Stack allocated class for disabling break.

class DisableBreak BASE_EMBEDDED {

 public:

  // Enter the debugger by storing the previous top context and setting the

  // current top context to the debugger context.

  explicit DisableBreak(bool disable_break)  {

    prev_disable_break_ = Debug::disable_break();

    Debug::set_disable_break(disable_break);

  }

  ~DisableBreak() {

    Debug::set_disable_break(prev_disable_break_);

  }

 private:

  // The previous state of the disable break used to restore the value when this

  // object is destructed.

  bool prev_disable_break_;

};

// Debug_Address encapsulates the Address pointers used in generating debug

// code.

class Debug_Address {

 public:

  Debug_Address(Debug::AddressId id, int reg = 0)

    : id_(id), reg_(reg) {

    ASSERT(reg == 0 || id == Debug::k_register_address);

  }

  static Debug_Address AfterBreakTarget() {

    return Debug_Address(Debug::k_after_break_target_address);

  }

  static Debug_Address DebugBreakReturn() {

    return Debug_Address(Debug::k_debug_break_return_address);

  }

  static Debug_Address Register(int reg) {

    return Debug_Address(Debug::k_register_address, reg);

  }

  Address address() const {

    switch (id_) {

      case Debug::k_after_break_target_address:

        return reinterpret_cast<Address>(Debug::after_break_target_address());

      case Debug::k_debug_break_return_address:

        return reinterpret_cast<Address>(Debug::debug_break_return_address());

      case Debug::k_register_address:

        return reinterpret_cast<Address>(Debug::register_address(reg_));

      default:

        UNREACHABLE();

        return NULL;

    }

  }

 private:

  Debug::AddressId id_;

  int reg_;

};

} }  // namespace v8::internal

#endif  // V8_V8_DEBUG_H_