From 9f4fc77e1e2b83b762bbd6766fcdb325759ca9a9 Mon Sep 17 00:00:00 2001
From: "mstarzinger@chromium.org"
 <mstarzinger@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Mon, 29 Jul 2013 17:59:02 +0000
Subject: [PATCH] Compilation type and state allocate an unnecessary Smi on
 v8::Script.

This patch combines them into a single field, and adjusts the accessors
and setters to take the enum type directly, rather than converting to and
from a Smi value.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/20758002

Patch from Mike West <mkwst@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15940 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/accessors.cc       |  5 ++---
 src/compiler.cc        |  6 ++----
 src/factory.cc         |  4 +---
 src/isolate.cc         |  6 +++---
 src/liveedit.cc        |  5 ++++-
 src/objects-inl.h      | 21 +++++++++++++++++++--
 src/objects-printer.cc |  3 +--
 src/objects.h          | 32 +++++++++++++++++++++-----------
 src/runtime.cc         |  2 +-
 9 files changed, 54 insertions(+), 30 deletions(-)

diff --git a/src/accessors.cc b/src/accessors.cc
index 51db361..a43eb78 100644
--- a/src/accessors.cc
+++ b/src/accessors.cc
@@ -292,7 +292,7 @@ const AccessorDescriptor Accessors::ScriptType = {
 
 MaybeObject* Accessors::ScriptGetCompilationType(Object* object, void*) {
   Object* script = JSValue::cast(object)->value();
-  return Script::cast(script)->compilation_type();
+  return Smi::FromInt(Script::cast(script)->compilation_type());
 }
 
 
@@ -388,8 +388,7 @@ MaybeObject* Accessors::ScriptGetEvalFromScriptPosition(Object* object, void*) {
   Handle<Script> script(raw_script);
 
   // If this is not a script compiled through eval there is no eval position.
-  int compilation_type = Smi::cast(script->compilation_type())->value();
-  if (compilation_type != Script::COMPILATION_TYPE_EVAL) {
+  if (script->compilation_type() != Script::COMPILATION_TYPE_EVAL) {
     return script->GetHeap()->undefined_value();
   }
 
diff --git a/src/compiler.cc b/src/compiler.cc
index ebd1266..f4112d7 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -558,8 +558,7 @@ static Handle<SharedFunctionInfo> MakeFunctionInfo(CompilationInfo* info) {
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
   if (info->is_eval()) {
-    Script::CompilationType compilation_type = Script::COMPILATION_TYPE_EVAL;
-    script->set_compilation_type(Smi::FromInt(compilation_type));
+    script->set_compilation_type(Script::COMPILATION_TYPE_EVAL);
     // For eval scripts add information on the function from which eval was
     // called.
     if (info->is_eval()) {
@@ -650,8 +649,7 @@ static Handle<SharedFunctionInfo> MakeFunctionInfo(CompilationInfo* info) {
   // the instances of the function.
   SetExpectedNofPropertiesFromEstimate(result, lit->expected_property_count());
 
-  script->set_compilation_state(
-      Smi::FromInt(Script::COMPILATION_STATE_COMPILED));
+  script->set_compilation_state(Script::COMPILATION_STATE_COMPILED);
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
   // Notify debugger
diff --git a/src/factory.cc b/src/factory.cc
index 52a6588..e2a38c8 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -453,13 +453,11 @@ Handle<Script> Factory::NewScript(Handle<String> source) {
   script->set_data(heap->undefined_value());
   script->set_context_data(heap->undefined_value());
   script->set_type(Smi::FromInt(Script::TYPE_NORMAL));
-  script->set_compilation_type(Smi::FromInt(Script::COMPILATION_TYPE_HOST));
-  script->set_compilation_state(
-      Smi::FromInt(Script::COMPILATION_STATE_INITIAL));
   script->set_wrapper(*wrapper);
   script->set_line_ends(heap->undefined_value());
   script->set_eval_from_shared(heap->undefined_value());
   script->set_eval_from_instructions_offset(Smi::FromInt(0));
+  script->set_flags(Smi::FromInt(0));
 
   return script;
 }
diff --git a/src/isolate.cc b/src/isolate.cc
index 058ee8a..346ece8 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -816,9 +816,9 @@ Handle<JSArray> Isolate::CaptureCurrentStackTrace(
       }
 
       if (options & StackTrace::kIsEval) {
-        int type = Smi::cast(script->compilation_type())->value();
-        Handle<Object> is_eval = (type == Script::COMPILATION_TYPE_EVAL) ?
-            factory()->true_value() : factory()->false_value();
+        Handle<Object> is_eval =
+            script->compilation_type() == Script::COMPILATION_TYPE_EVAL ?
+                factory()->true_value() : factory()->false_value();
         CHECK_NOT_EMPTY_HANDLE(this,
                                JSObject::SetLocalPropertyIgnoreAttributes(
                                    stack_frame, eval_key, is_eval, NONE));
diff --git a/src/liveedit.cc b/src/liveedit.cc
index b998a26..33586de 100644
--- a/src/liveedit.cc
+++ b/src/liveedit.cc
@@ -1558,11 +1558,14 @@ static Handle<Script> CreateScriptCopy(Handle<Script> original) {
   copy->set_data(original->data());
   copy->set_type(original->type());
   copy->set_context_data(original->context_data());
-  copy->set_compilation_type(original->compilation_type());
   copy->set_eval_from_shared(original->eval_from_shared());
   copy->set_eval_from_instructions_offset(
       original->eval_from_instructions_offset());
 
+  // Copy all the flags, but clear compilation state.
+  copy->set_flags(original->flags());
+  copy->set_compilation_state(Script::COMPILATION_STATE_INITIAL);
+
   return copy;
 }
 
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 3189d84..ef30496 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -4482,12 +4482,29 @@ ACCESSORS(Script, data, Object, kDataOffset)
 ACCESSORS(Script, context_data, Object, kContextOffset)
 ACCESSORS(Script, wrapper, Foreign, kWrapperOffset)
 ACCESSORS_TO_SMI(Script, type, kTypeOffset)
-ACCESSORS_TO_SMI(Script, compilation_type, kCompilationTypeOffset)
-ACCESSORS_TO_SMI(Script, compilation_state, kCompilationStateOffset)
 ACCESSORS(Script, line_ends, Object, kLineEndsOffset)
 ACCESSORS(Script, eval_from_shared, Object, kEvalFromSharedOffset)
 ACCESSORS_TO_SMI(Script, eval_from_instructions_offset,
                  kEvalFrominstructionsOffsetOffset)
+ACCESSORS_TO_SMI(Script, flags, kFlagsOffset)
+
+Script::CompilationType Script::compilation_type() {
+  return BooleanBit::get(flags(), kCompilationTypeBit) ?
+      COMPILATION_TYPE_EVAL : COMPILATION_TYPE_HOST;
+}
+void Script::set_compilation_type(CompilationType type) {
+  set_flags(BooleanBit::set(flags(), kCompilationTypeBit,
+      type == COMPILATION_TYPE_EVAL));
+}
+Script::CompilationState Script::compilation_state() {
+  return BooleanBit::get(flags(), kCompilationStateBit) ?
+      COMPILATION_STATE_COMPILED : COMPILATION_STATE_INITIAL;
+}
+void Script::set_compilation_state(CompilationState state) {
+  set_flags(BooleanBit::set(flags(), kCompilationStateBit,
+      state == COMPILATION_STATE_COMPILED));
+}
+
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
 ACCESSORS(DebugInfo, shared, SharedFunctionInfo, kSharedFunctionInfoIndex)
diff --git a/src/objects-printer.cc b/src/objects-printer.cc
index 2327cba..6b2a3f0 100644
--- a/src/objects-printer.cc
+++ b/src/objects-printer.cc
@@ -1202,8 +1202,7 @@ void Script::ScriptPrint(FILE* out) {
   context_data()->ShortPrint(out);
   PrintF(out, "\n - wrapper: ");
   wrapper()->ShortPrint(out);
-  PrintF(out, "\n - compilation type: ");
-  compilation_type()->ShortPrint(out);
+  PrintF(out, "\n - compilation type: %d", compilation_type());
   PrintF(out, "\n - line ends: ");
   line_ends()->ShortPrint(out);
   PrintF(out, "\n - eval from shared: ");
diff --git a/src/objects.h b/src/objects.h
index 36611ee..3881874 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -5849,12 +5849,6 @@ class Script: public Struct {
   // [type]: the script type.
   DECL_ACCESSORS(type, Smi)
 
-  // [compilation]: how the the script was compiled.
-  DECL_ACCESSORS(compilation_type, Smi)
-
-  // [is_compiled]: determines whether the script has already been compiled.
-  DECL_ACCESSORS(compilation_state, Smi)
-
   // [line_ends]: FixedArray of line ends positions.
   DECL_ACCESSORS(line_ends, Object)
 
@@ -5866,6 +5860,19 @@ class Script: public Struct {
   // function from which eval was called where eval was called.
   DECL_ACCESSORS(eval_from_instructions_offset, Smi)
 
+  // [flags]: Holds an exciting bitfield.
+  DECL_ACCESSORS(flags, Smi)
+
+  // [compilation_type]: how the the script was compiled. Encoded in the
+  // 'flags' field.
+  inline CompilationType compilation_type();
+  inline void set_compilation_type(CompilationType type);
+
+  // [compilation_state]: determines whether the script has already been
+  // compiled. Encoded in the 'flags' field.
+  inline CompilationState compilation_state();
+  inline void set_compilation_state(CompilationState state);
+
   static inline Script* cast(Object* obj);
 
   // If script source is an external string, check that the underlying
@@ -5884,17 +5891,20 @@ class Script: public Struct {
   static const int kContextOffset = kDataOffset + kPointerSize;
   static const int kWrapperOffset = kContextOffset + kPointerSize;
   static const int kTypeOffset = kWrapperOffset + kPointerSize;
-  static const int kCompilationTypeOffset = kTypeOffset + kPointerSize;
-  static const int kCompilationStateOffset =
-      kCompilationTypeOffset + kPointerSize;
-  static const int kLineEndsOffset = kCompilationStateOffset + kPointerSize;
+  static const int kLineEndsOffset = kTypeOffset + kPointerSize;
   static const int kIdOffset = kLineEndsOffset + kPointerSize;
   static const int kEvalFromSharedOffset = kIdOffset + kPointerSize;
   static const int kEvalFrominstructionsOffsetOffset =
       kEvalFromSharedOffset + kPointerSize;
-  static const int kSize = kEvalFrominstructionsOffsetOffset + kPointerSize;
+  static const int kFlagsOffset =
+      kEvalFrominstructionsOffsetOffset + kPointerSize;
+  static const int kSize = kFlagsOffset + kPointerSize;
 
  private:
+  // Bit positions in the flags field.
+  static const int kCompilationTypeBit = 0;
+  static const int kCompilationStateBit = 1;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(Script);
 };
 
diff --git a/src/runtime.cc b/src/runtime.cc
index 29b43ff..afa728d 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -12887,7 +12887,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugSetScriptSource) {
   RUNTIME_ASSERT(script_wrapper->value()->IsScript());
   Handle<Script> script(Script::cast(script_wrapper->value()));
 
-  int compilation_state = Smi::cast(script->compilation_state())->value();
+  int compilation_state = script->compilation_state();
   RUNTIME_ASSERT(compilation_state == Script::COMPILATION_STATE_INITIAL);
   script->set_source(*source);
 
-- 
2.7.4