CSE2410 Fall 2014 Bounce

// Copyright 2012 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_COMPILER_H_

#define V8_COMPILER_H_

#include "allocation.h"

#include "ast.h"

#include "zone.h"

namespace v8 {

namespace internal {

class ScriptDataImpl;

class HydrogenCodeStub;

// ParseRestriction is used to restrict the set of valid statements in a

// unit of compilation.  Restriction violations cause a syntax error.

enum ParseRestriction {

  NO_PARSE_RESTRICTION,         // All expressions are allowed.

  ONLY_SINGLE_FUNCTION_LITERAL  // Only a single FunctionLiteral expression.

};

struct OffsetRange {

  OffsetRange(int from, int to) : from(from), to(to) {}

  int from;

  int to;

};

// CompilationInfo encapsulates some information known at compile time.  It

// is constructed based on the resources available at compile-time.

class CompilationInfo {

 public:

  CompilationInfo(Handle<JSFunction> closure, Zone* zone);

  virtual ~CompilationInfo();

  Isolate* isolate() const {

    return isolate_;

  }

  Zone* zone() { return zone_; }

  bool is_osr() const { return !osr_ast_id_.IsNone(); }

  bool is_lazy() const { return IsLazy::decode(flags_); }

  bool is_eval() const { return IsEval::decode(flags_); }

  bool is_global() const { return IsGlobal::decode(flags_); }

  bool is_classic_mode() const { return language_mode() == CLASSIC_MODE; }

  bool is_extended_mode() const { return language_mode() == EXTENDED_MODE; }

  LanguageMode language_mode() const {

    return LanguageModeField::decode(flags_);

  }

  bool is_in_loop() const { return IsInLoop::decode(flags_); }

  FunctionLiteral* function() const { return function_; }

  Scope* scope() const { return scope_; }

  Scope* global_scope() const { return global_scope_; }

  Handle<Code> code() const { return code_; }

  Handle<JSFunction> closure() const { return closure_; }

  Handle<SharedFunctionInfo> shared_info() const { return shared_info_; }

  Handle<Script> script() const { return script_; }

  HydrogenCodeStub* code_stub() const {return code_stub_; }

  v8::Extension* extension() const { return extension_; }

  ScriptDataImpl* pre_parse_data() const { return pre_parse_data_; }

  Handle<Context> context() const { return context_; }

  BailoutId osr_ast_id() const { return osr_ast_id_; }

  uint32_t osr_pc_offset() const { return osr_pc_offset_; }

  int opt_count() const { return opt_count_; }

  int num_parameters() const;

  int num_heap_slots() const;

  Code::Flags flags() const;

  void MarkAsEval() {

    ASSERT(!is_lazy());

    flags_ |= IsEval::encode(true);

  }

  void MarkAsGlobal() {

    ASSERT(!is_lazy());

    flags_ |= IsGlobal::encode(true);

  }

  void SetLanguageMode(LanguageMode language_mode) {

    ASSERT(this->language_mode() == CLASSIC_MODE ||

           this->language_mode() == language_mode ||

           language_mode == EXTENDED_MODE);

    flags_ = LanguageModeField::update(flags_, language_mode);

  }

  void MarkAsInLoop() {

    ASSERT(is_lazy());

    flags_ |= IsInLoop::encode(true);

  }

  void MarkAsNative() {

    flags_ |= IsNative::encode(true);

  }

  bool is_native() const {

    return IsNative::decode(flags_);

  }

  bool is_calling() const {

    return is_deferred_calling() || is_non_deferred_calling();

  }

  void MarkAsDeferredCalling() {

    flags_ |= IsDeferredCalling::encode(true);

  }

  bool is_deferred_calling() const {

    return IsDeferredCalling::decode(flags_);

  }

  void MarkAsNonDeferredCalling() {

    flags_ |= IsNonDeferredCalling::encode(true);

  }

  bool is_non_deferred_calling() const {

    return IsNonDeferredCalling::decode(flags_);

  }

  void MarkAsSavesCallerDoubles() {

    flags_ |= SavesCallerDoubles::encode(true);

  }

  bool saves_caller_doubles() const {

    return SavesCallerDoubles::decode(flags_);

  }

  void MarkAsRequiresFrame() {

    flags_ |= RequiresFrame::encode(true);

  }

  bool requires_frame() const {

    return RequiresFrame::decode(flags_);

  }

  void SetParseRestriction(ParseRestriction restriction) {

    flags_ = ParseRestricitonField::update(flags_, restriction);

  }

  ParseRestriction parse_restriction() const {

    return ParseRestricitonField::decode(flags_);

  }

  void SetFunction(FunctionLiteral* literal) {

    ASSERT(function_ == NULL);

    function_ = literal;

  }

  void SetScope(Scope* scope) {

    ASSERT(scope_ == NULL);

    scope_ = scope;

  }

  void SetGlobalScope(Scope* global_scope) {

    ASSERT(global_scope_ == NULL);

    global_scope_ = global_scope;

  }

  void SetCode(Handle<Code> code) { code_ = code; }

  void SetExtension(v8::Extension* extension) {

    ASSERT(!is_lazy());

    extension_ = extension;

  }

  void SetPreParseData(ScriptDataImpl* pre_parse_data) {

    ASSERT(!is_lazy());

    pre_parse_data_ = pre_parse_data;

  }

  void SetContext(Handle<Context> context) {

    context_ = context;

  }

  void MarkCompilingForDebugging(Handle<Code> current_code) {

    ASSERT(mode_ != OPTIMIZE);

    ASSERT(current_code->kind() == Code::FUNCTION);

    flags_ |= IsCompilingForDebugging::encode(true);

    if (current_code->is_compiled_optimizable()) {

      EnableDeoptimizationSupport();

    } else {

      mode_ = CompilationInfo::NONOPT;

    }

  }

  bool IsCompilingForDebugging() {

    return IsCompilingForDebugging::decode(flags_);

  }

  bool ShouldTrapOnDeopt() const {

    return (FLAG_trap_on_deopt && IsOptimizing()) ||

        (FLAG_trap_on_stub_deopt && IsStub());

  }

  bool has_global_object() const {

    return !closure().is_null() &&

        (closure()->context()->global_object() != NULL);

  }

  GlobalObject* global_object() const {

    return has_global_object() ? closure()->context()->global_object() : NULL;

  }

  // Accessors for the different compilation modes.

  bool IsOptimizing() const { return mode_ == OPTIMIZE; }

  bool IsOptimizable() const { return mode_ == BASE; }

  bool IsStub() const { return mode_ == STUB; }

  void SetOptimizing(BailoutId osr_ast_id) {

    SetMode(OPTIMIZE);

    osr_ast_id_ = osr_ast_id;

  }

  void DisableOptimization();

  // Deoptimization support.

  bool HasDeoptimizationSupport() const {

    return SupportsDeoptimization::decode(flags_);

  }

  void EnableDeoptimizationSupport() {

    ASSERT(IsOptimizable());

    flags_ |= SupportsDeoptimization::encode(true);

  }

  // Determines whether or not to insert a self-optimization header.

  bool ShouldSelfOptimize();

  // Reset code to the unoptimized version when optimization is aborted.

  void AbortOptimization() {

    SetCode(handle(shared_info()->code()));

  }

  void set_deferred_handles(DeferredHandles* deferred_handles) {

    ASSERT(deferred_handles_ == NULL);

    deferred_handles_ = deferred_handles;

  }

  ZoneList<Handle<HeapObject> >* dependencies(

      DependentCode::DependencyGroup group) {

    if (dependencies_[group] == NULL) {

      dependencies_[group] = new(zone_) ZoneList<Handle<HeapObject> >(2, zone_);

    }

    return dependencies_[group];

  }

  void CommitDependencies(Handle<Code> code);

  void RollbackDependencies();

  void SaveHandles() {

    SaveHandle(&closure_);

    SaveHandle(&shared_info_);

    SaveHandle(&context_);

    SaveHandle(&script_);

  }

  BailoutReason bailout_reason() const { return bailout_reason_; }

  void set_bailout_reason(BailoutReason reason) { bailout_reason_ = reason; }

  int prologue_offset() const {

    ASSERT_NE(Code::kPrologueOffsetNotSet, prologue_offset_);

    return prologue_offset_;

  }

  void set_prologue_offset(int prologue_offset) {

    ASSERT_EQ(Code::kPrologueOffsetNotSet, prologue_offset_);

    prologue_offset_ = prologue_offset;

  }

  // Adds offset range [from, to) where fp register does not point

  // to the current frame base. Used in CPU profiler to detect stack

  // samples where top frame is not set up.

  inline void AddNoFrameRange(int from, int to) {

    if (no_frame_ranges_) no_frame_ranges_->Add(OffsetRange(from, to));

  }

  List<OffsetRange>* ReleaseNoFrameRanges() {

    List<OffsetRange>* result = no_frame_ranges_;

    no_frame_ranges_ = NULL;

    return result;

  }

  Handle<Foreign> object_wrapper() {

    if (object_wrapper_.is_null()) {

      object_wrapper_ =

          isolate()->factory()->NewForeign(reinterpret_cast<Address>(this));

    }

    return object_wrapper_;

  }

  void AbortDueToDependencyChange() {

    ASSERT(!isolate()->optimizing_compiler_thread()->IsOptimizerThread());

    abort_due_to_dependency_ = true;

  }

  bool HasAbortedDueToDependencyChange() {

    ASSERT(!isolate()->optimizing_compiler_thread()->IsOptimizerThread());

    return abort_due_to_dependency_;

  }

  void set_osr_pc_offset(uint32_t pc_offset) {

    osr_pc_offset_ = pc_offset;

  }

  bool HasSameOsrEntry(Handle<JSFunction> function, uint32_t pc_offset) {

    return osr_pc_offset_ == pc_offset && function.is_identical_to(closure_);

  }

 protected:

  CompilationInfo(Handle<Script> script,

                  Zone* zone);

  CompilationInfo(Handle<SharedFunctionInfo> shared_info,

                  Zone* zone);

  CompilationInfo(HydrogenCodeStub* stub,

                  Isolate* isolate,

                  Zone* zone);

 private:

  Isolate* isolate_;

  // Compilation mode.

  // BASE is generated by the full codegen, optionally prepared for bailouts.

  // OPTIMIZE is optimized code generated by the Hydrogen-based backend.

  // NONOPT is generated by the full codegen and is not prepared for

  //   recompilation/bailouts.  These functions are never recompiled.

  enum Mode {

    BASE,

    OPTIMIZE,

    NONOPT,

    STUB

  };

  void Initialize(Isolate* isolate, Mode mode, Zone* zone);

  void SetMode(Mode mode) {

    ASSERT(isolate()->use_crankshaft());

    mode_ = mode;

  }

  // Flags using template class BitField<type, start, length>.  All are

  // false by default.

  //

  // Compilation is either eager or lazy.

  class IsLazy:   public BitField<bool, 0, 1> {};

  // Flags that can be set for eager compilation.

  class IsEval:   public BitField<bool, 1, 1> {};

  class IsGlobal: public BitField<bool, 2, 1> {};

  // Flags that can be set for lazy compilation.

  class IsInLoop: public BitField<bool, 3, 1> {};

  // Strict mode - used in eager compilation.

  class LanguageModeField: public BitField<LanguageMode, 4, 2> {};

  // Is this a function from our natives.

  class IsNative: public BitField<bool, 6, 1> {};

  // Is this code being compiled with support for deoptimization..

  class SupportsDeoptimization: public BitField<bool, 7, 1> {};

  // If compiling for debugging produce just full code matching the

  // initial mode setting.

  class IsCompilingForDebugging: public BitField<bool, 8, 1> {};

  // If the compiled code contains calls that require building a frame

  class IsCalling: public BitField<bool, 9, 1> {};

  // If the compiled code contains calls that require building a frame

  class IsDeferredCalling: public BitField<bool, 10, 1> {};

  // If the compiled code contains calls that require building a frame

  class IsNonDeferredCalling: public BitField<bool, 11, 1> {};

  // If the compiled code saves double caller registers that it clobbers.

  class SavesCallerDoubles: public BitField<bool, 12, 1> {};

  // If the set of valid statements is restricted.

  class ParseRestricitonField: public BitField<ParseRestriction, 13, 1> {};

  // If the function requires a frame (for unspecified reasons)

  class RequiresFrame: public BitField<bool, 14, 1> {};

  unsigned flags_;

  // Fields filled in by the compilation pipeline.

  // AST filled in by the parser.

  FunctionLiteral* function_;

  // The scope of the function literal as a convenience.  Set to indicate

  // that scopes have been analyzed.

  Scope* scope_;

  // The global scope provided as a convenience.

  Scope* global_scope_;

  // For compiled stubs, the stub object

  HydrogenCodeStub* code_stub_;

  // The compiled code.

  Handle<Code> code_;

  // Possible initial inputs to the compilation process.

  Handle<JSFunction> closure_;

  Handle<SharedFunctionInfo> shared_info_;

  Handle<Script> script_;

  // Fields possibly needed for eager compilation, NULL by default.

  v8::Extension* extension_;

  ScriptDataImpl* pre_parse_data_;

  // The context of the caller for eval code, and the global context for a

  // global script. Will be a null handle otherwise.

  Handle<Context> context_;

  // Compilation mode flag and whether deoptimization is allowed.

  Mode mode_;

  BailoutId osr_ast_id_;

  // The pc_offset corresponding to osr_ast_id_ in unoptimized code.

  // We can look this up in the back edge table, but cache it for quick access.

  uint32_t osr_pc_offset_;

  // Flag whether compilation needs to be aborted due to dependency change.

  bool abort_due_to_dependency_;

  // The zone from which the compilation pipeline working on this

  // CompilationInfo allocates.

  Zone* zone_;

  DeferredHandles* deferred_handles_;

  ZoneList<Handle<HeapObject> >* dependencies_[DependentCode::kGroupCount];

  template<typename T>

  void SaveHandle(Handle<T> *object) {

    if (!object->is_null()) {

      Handle<T> handle(*(*object));

      *object = handle;

    }

  }

  BailoutReason bailout_reason_;

  int prologue_offset_;

  List<OffsetRange>* no_frame_ranges_;

  // A copy of shared_info()->opt_count() to avoid handle deref

  // during graph optimization.

  int opt_count_;

  Handle<Foreign> object_wrapper_;

  DISALLOW_COPY_AND_ASSIGN(CompilationInfo);

};

// Exactly like a CompilationInfo, except also creates and enters a

// Zone on construction and deallocates it on exit.

class CompilationInfoWithZone: public CompilationInfo {

 public:

  explicit CompilationInfoWithZone(Handle<Script> script)

      : CompilationInfo(script, &zone_),

        zone_(script->GetIsolate()) {}

  explicit CompilationInfoWithZone(Handle<SharedFunctionInfo> shared_info)

      : CompilationInfo(shared_info, &zone_),

        zone_(shared_info->GetIsolate()) {}

  explicit CompilationInfoWithZone(Handle<JSFunction> closure)

      : CompilationInfo(closure, &zone_),

        zone_(closure->GetIsolate()) {}

  CompilationInfoWithZone(HydrogenCodeStub* stub, Isolate* isolate)

      : CompilationInfo(stub, isolate, &zone_),

        zone_(isolate) {}

  // Virtual destructor because a CompilationInfoWithZone has to exit the

  // zone scope and get rid of dependent maps even when the destructor is

  // called when cast as a CompilationInfo.

  virtual ~CompilationInfoWithZone() {

    RollbackDependencies();

  }

 private:

  Zone zone_;

};

// A wrapper around a CompilationInfo that detaches the Handles from

// the underlying DeferredHandleScope and stores them in info_ on

// destruction.

class CompilationHandleScope BASE_EMBEDDED {

 public:

  explicit CompilationHandleScope(CompilationInfo* info)

      : deferred_(info->isolate()), info_(info) {}

  ~CompilationHandleScope() {

    info_->set_deferred_handles(deferred_.Detach());

  }

 private:

  DeferredHandleScope deferred_;

  CompilationInfo* info_;

};

class HGraph;

class HOptimizedGraphBuilder;

class LChunk;

// A helper class that calls the three compilation phases in

// Crankshaft and keeps track of its state.  The three phases

// CreateGraph, OptimizeGraph and GenerateAndInstallCode can either

// fail, bail-out to the full code generator or succeed.  Apart from

// their return value, the status of the phase last run can be checked

// using last_status().

class RecompileJob: public ZoneObject {

 public:

  explicit RecompileJob(CompilationInfo* info)

      : info_(info),

        graph_builder_(NULL),

        graph_(NULL),

        chunk_(NULL),

        last_status_(FAILED),

        awaiting_install_(false) { }

  enum Status {

    FAILED, BAILED_OUT, SUCCEEDED

  };

  MUST_USE_RESULT Status CreateGraph();

  MUST_USE_RESULT Status OptimizeGraph();

  MUST_USE_RESULT Status GenerateAndInstallCode();

  Status last_status() const { return last_status_; }

  CompilationInfo* info() const { return info_; }

  Isolate* isolate() const { return info()->isolate(); }

  MUST_USE_RESULT Status AbortOptimization() {

    info_->AbortOptimization();

    info_->shared_info()->DisableOptimization(info_->bailout_reason());

    return SetLastStatus(BAILED_OUT);

  }

  void WaitForInstall() {

    ASSERT(info_->is_osr());

    awaiting_install_ = true;

  }

  bool IsWaitingForInstall() { return awaiting_install_; }

 private:

  CompilationInfo* info_;

  HOptimizedGraphBuilder* graph_builder_;

  HGraph* graph_;

  LChunk* chunk_;

  TimeDelta time_taken_to_create_graph_;

  TimeDelta time_taken_to_optimize_;

  TimeDelta time_taken_to_codegen_;

  Status last_status_;

  bool awaiting_install_;

  MUST_USE_RESULT Status SetLastStatus(Status status) {

    last_status_ = status;

    return last_status_;

  }

  void RecordOptimizationStats();

  struct Timer {

    Timer(RecompileJob* job, TimeDelta* location)

        : job_(job), location_(location) {

      ASSERT(location_ != NULL);

      timer_.Start();

    }

    ~Timer() {

      *location_ += timer_.Elapsed();

    }

    RecompileJob* job_;

    ElapsedTimer timer_;

    TimeDelta* location_;

  };

};

// The V8 compiler

//

// General strategy: Source code is translated into an anonymous function w/o

// parameters which then can be executed. If the source code contains other

// functions, they will be compiled and allocated as part of the compilation

// of the source code.

// Please note this interface returns shared function infos.  This means you

// need to call Factory::NewFunctionFromSharedFunctionInfo before you have a

// real function with a context.

class Compiler : public AllStatic {

 public:

  // Call count before primitive functions trigger their own optimization.

  static const int kCallsUntilPrimitiveOpt = 200;

  // All routines return a SharedFunctionInfo.

  // If an error occurs an exception is raised and the return handle

  // contains NULL.

  // Compile a String source within a context.

  static Handle<SharedFunctionInfo> Compile(Handle<String> source,

                                            Handle<Object> script_name,

                                            int line_offset,

                                            int column_offset,

                                            bool is_shared_cross_origin,

                                            Handle<Context> context,

                                            v8::Extension* extension,

                                            ScriptDataImpl* pre_data,

                                            Handle<Object> script_data,

                                            NativesFlag is_natives_code);

  // Compile a String source within a context for Eval.

  static Handle<SharedFunctionInfo> CompileEval(Handle<String> source,

                                                Handle<Context> context,

                                                bool is_global,

                                                LanguageMode language_mode,

                                                ParseRestriction restriction,

                                                int scope_position);

  // Compile from function info (used for lazy compilation). Returns true on

  // success and false if the compilation resulted in a stack overflow.

  static bool CompileLazy(CompilationInfo* info);

  static bool RecompileConcurrent(Handle<JSFunction> function,

                                  uint32_t osr_pc_offset = 0);

  // Compile a shared function info object (the function is possibly lazily

  // compiled).

  static Handle<SharedFunctionInfo> BuildFunctionInfo(FunctionLiteral* node,

                                                      Handle<Script> script);

  // Set the function info for a newly compiled function.

  static void SetFunctionInfo(Handle<SharedFunctionInfo> function_info,

                              FunctionLiteral* lit,

                              bool is_toplevel,

                              Handle<Script> script);

  static Handle<Code> InstallOptimizedCode(RecompileJob* job);

#ifdef ENABLE_DEBUGGER_SUPPORT

  static bool MakeCodeForLiveEdit(CompilationInfo* info);

#endif

  static void RecordFunctionCompilation(Logger::LogEventsAndTags tag,

                                        CompilationInfo* info,

                                        Handle<SharedFunctionInfo> shared);

};

class CompilationPhase BASE_EMBEDDED {

 public:

  CompilationPhase(const char* name, CompilationInfo* info);

  ~CompilationPhase();

 protected:

  bool ShouldProduceTraceOutput() const;

  const char* name() const { return name_; }

  CompilationInfo* info() const { return info_; }

  Isolate* isolate() const { return info()->isolate(); }

  Zone* zone() { return &zone_; }

 private:

  const char* name_;

  CompilationInfo* info_;

  Zone zone_;

  unsigned info_zone_start_allocation_size_;

  ElapsedTimer timer_;

  DISALLOW_COPY_AND_ASSIGN(CompilationPhase);

};

} }  // namespace v8::internal

#endif  // V8_COMPILER_H_