Pack deopt ID into the return before and return after deopt instructions.

runtime/vm/deopt_instructions.cc

Index: runtime/vm/deopt_instructions.cc
diff --git a/runtime/vm/deopt_instructions.cc b/runtime/vm/deopt_instructions.cc
index 80f21bbf202714448a8c4f30911edcfcfc41ccd9..344004ca506fd0eeec986452f9a305570be4420f 100644
--- a/runtime/vm/deopt_instructions.cc
+++ b/runtime/vm/deopt_instructions.cc
@@ -126,38 +126,46 @@ class DeoptDoubleStackSlotInstr : public DeoptInstr {
 // deopt-id stored at 'object_table_index'. Uses the deopt-after
 // continuation point.
 class DeoptRetAddrAfterInstr : public DeoptInstr {
+ private:
+  static const intptr_t kFieldWidth = kBitsPerWord / 2;
+
  public:
-  explicit DeoptRetAddrAfterInstr(intptr_t object_table_index)
-      : object_table_index_(object_table_index) {
+  class ObjectTableIndex : public BitField<intptr_t, 0, kFieldWidth> { };
+  class DeoptId : public BitField<intptr_t, kFieldWidth, kFieldWidth> { };
+
+  DeoptRetAddrAfterInstr(intptr_t object_table_index, intptr_t deopt_id)
+      : object_table_index_(object_table_index), deopt_id_(deopt_id) {
     ASSERT(object_table_index >= 0);
+    ASSERT(deopt_id >= 0);
   }

[srdjan, 2012/10/02 17:34:49]

How about overloading constructor with:
DeoptRetAddrAfterInstr(intptr_t from_index), thus the knowledge of encoding of
from_index is hidden inside the class.

[Kevin Millikin (Google), 2012/10/03 07:05:36]

OK.

 
-  virtual intptr_t from_index() const { return object_table_index_; }
+  virtual intptr_t from_index() const {
+    return ObjectTableIndex::encode(object_table_index_) |
+        DeoptId::encode(deopt_id_);
+  }
   virtual DeoptInstr::Kind kind() const { return kSetRetAfterAddress; }
 
   virtual const char* ToCString() const {
-    const char* format = "ret aft oti:%"Pd"";
-    intptr_t len = OS::SNPrint(NULL, 0, format, object_table_index_);
+    const char* format = "ret aft oti:%"Pd"(%"Pd")";
+    intptr_t len = OS::SNPrint(NULL, 0, format, object_table_index_, deopt_id_);
     char* chars = Isolate::Current()->current_zone()->Alloc<char>(len + 1);
-    OS::SNPrint(chars, len + 1, format, object_table_index_);
+    OS::SNPrint(chars, len + 1, format, object_table_index_, deopt_id_);
     return chars;
   }
 
   void Execute(DeoptimizationContext* deopt_context, intptr_t to_index) {
     Function& function = Function::Handle(deopt_context->isolate());
     function ^= deopt_context->ObjectAt(object_table_index_);
-    Smi& deopt_id_as_smi = Smi::Handle(deopt_context->isolate());
-    deopt_id_as_smi ^= deopt_context->ObjectAt(object_table_index_ + 1);
     const Code& code =
         Code::Handle(deopt_context->isolate(), function.unoptimized_code());
-    uword continue_at_pc =
-        code.GetDeoptAfterPcAtDeoptId(deopt_id_as_smi.Value());
+    uword continue_at_pc = code.GetDeoptAfterPcAtDeoptId(deopt_id_);
     intptr_t* to_addr = deopt_context->GetToFrameAddressAt(to_index);
     *to_addr = continue_at_pc;
   }
 
  private:
   const intptr_t object_table_index_;
+  const intptr_t deopt_id_;
 
   DISALLOW_COPY_AND_ASSIGN(DeoptRetAddrAfterInstr);
 };
@@ -167,38 +175,46 @@ class DeoptRetAddrAfterInstr : public DeoptInstr {
 // deopt-id stored at 'object_table_index'. Uses the deopt-before
 // continuation point.
 class DeoptRetAddrBeforeInstr : public DeoptInstr {
+ private:
+  static const intptr_t kFieldWidth = kBitsPerWord / 2;
+
  public:
-  explicit DeoptRetAddrBeforeInstr(intptr_t object_table_index)
-      : object_table_index_(object_table_index) {
+  class ObjectTableIndex : public BitField<intptr_t, 0, kFieldWidth> { };
+  class DeoptId : public BitField<intptr_t, kFieldWidth, kFieldWidth> { };
+
+  DeoptRetAddrBeforeInstr(intptr_t object_table_index, intptr_t deopt_id)
+      : object_table_index_(object_table_index), deopt_id_(deopt_id) {

[srdjan, 2012/10/02 17:34:49]

ditto.

     ASSERT(object_table_index >= 0);
+    ASSERT(deopt_id_ >= 0);
   }
 
-  virtual intptr_t from_index() const { return object_table_index_; }
+  virtual intptr_t from_index() const {
+    return ObjectTableIndex::encode(object_table_index_) |
+        DeoptId::encode(deopt_id_);
+  }
   virtual DeoptInstr::Kind kind() const { return kSetRetBeforeAddress; }
 
   virtual const char* ToCString() const {
-    const char* format = "ret bef oti:%"Pd"";
-    intptr_t len = OS::SNPrint(NULL, 0, format, object_table_index_);
+    const char* format = "ret bef oti:%"Pd"(%"Pd")";
+    intptr_t len = OS::SNPrint(NULL, 0, format, object_table_index_, deopt_id_);
     char* chars = Isolate::Current()->current_zone()->Alloc<char>(len + 1);
-    OS::SNPrint(chars, len + 1, format, object_table_index_);
+    OS::SNPrint(chars, len + 1, format, object_table_index_, deopt_id_);
     return chars;
   }
 
   void Execute(DeoptimizationContext* deopt_context, intptr_t to_index) {
     Function& function = Function::Handle(deopt_context->isolate());
     function ^= deopt_context->ObjectAt(object_table_index_);
-    Smi& deopt_id_as_smi = Smi::Handle(deopt_context->isolate());
-    deopt_id_as_smi ^= deopt_context->ObjectAt(object_table_index_ + 1);
     const Code& code =
         Code::Handle(deopt_context->isolate(), function.unoptimized_code());
-    uword continue_at_pc =
-        code.GetDeoptBeforePcAtDeoptId(deopt_id_as_smi.Value());
+    uword continue_at_pc = code.GetDeoptBeforePcAtDeoptId(deopt_id_);
     intptr_t* to_addr = deopt_context->GetToFrameAddressAt(to_index);
     *to_addr = continue_at_pc;
   }
 
  private:
   const intptr_t object_table_index_;
+  const intptr_t deopt_id_;
 
   DISALLOW_COPY_AND_ASSIGN(DeoptRetAddrBeforeInstr);
 };
@@ -383,8 +399,14 @@ DeoptInstr* DeoptInstr::Create(intptr_t kind_as_int, intptr_t from_index) {
   switch (kind) {
     case kCopyStackSlot: return new DeoptStackSlotInstr(from_index);
     case kCopyDoubleStackSlot: return new DeoptDoubleStackSlotInstr(from_index);
-    case kSetRetAfterAddress: return new DeoptRetAddrAfterInstr(from_index);
-    case kSetRetBeforeAddress: return new DeoptRetAddrBeforeInstr(from_index);
+    case kSetRetAfterAddress:
+      return new DeoptRetAddrAfterInstr(
+          DeoptRetAddrAfterInstr::ObjectTableIndex::decode(from_index),
+          DeoptRetAddrAfterInstr::DeoptId::decode(from_index));
+    case kSetRetBeforeAddress:
+      return new DeoptRetAddrBeforeInstr(
+          DeoptRetAddrBeforeInstr::ObjectTableIndex::decode(from_index),
+          DeoptRetAddrBeforeInstr::DeoptId::decode(from_index));
     case kCopyConstant:  return new DeoptConstantInstr(from_index);
     case kCopyRegister:  return new DeoptRegisterInstr(from_index);
     case kCopyXmmRegister: return new DeoptXmmRegisterInstr(from_index);
@@ -413,22 +435,18 @@ intptr_t DeoptInfoBuilder::FindOrAddObjectInTable(const Object& obj) const {
 void DeoptInfoBuilder::AddReturnAddressBefore(const Function& function,
                                               intptr_t deopt_id,
                                               intptr_t to_index) {
-  const intptr_t object_table_index = object_table_.Length();
-  object_table_.Add(function);
-  object_table_.Add(Smi::ZoneHandle(Smi::New(deopt_id)));
+  const intptr_t object_table_index = FindOrAddObjectInTable(function);
   ASSERT(to_index == instructions_.length());
-  instructions_.Add(new DeoptRetAddrBeforeInstr(object_table_index));
+  instructions_.Add(new DeoptRetAddrBeforeInstr(object_table_index, deopt_id));
 }
 
 
 void DeoptInfoBuilder::AddReturnAddressAfter(const Function& function,
                                              intptr_t deopt_id,
                                              intptr_t to_index) {
-  const intptr_t object_table_index = object_table_.Length();
-  object_table_.Add(function);
-  object_table_.Add(Smi::ZoneHandle(Smi::New(deopt_id)));
+  const intptr_t object_table_index = FindOrAddObjectInTable(function);
   ASSERT(to_index == instructions_.length());
-  instructions_.Add(new DeoptRetAddrAfterInstr(object_table_index));
+  instructions_.Add(new DeoptRetAddrAfterInstr(object_table_index, deopt_id));
 }