Special printing for type feedback vectors.

Gdb macro jfv on an object will print it as a feedback vector.
Printouts look like this:

DebugPrint: 0x5dc0d2ad: [TypeFeedbackVector]
 - length: 12
 - ics with type info: 3
 - generic ics: 0
 ICSlot 0 CALL_IC MONOMORPHIC
  [4]: 0x5dc0d365 WeakCell for 0x5dc0cd69 <JS Function foo (SharedFunctionInfo 0x5dc0cb0d)>
  [5]: 0x4203c4c1 <Code: HANDLER>
 ICSlot 1 LOAD_IC MONOMORPHIC
  [6]: 0x5dc0d1f5 WeakCell for 0x3a710481 <Map(FAST_HOLEY_SMI_ELEMENTS)>
  [7]: 0x4203a1c1 <Code: HANDLER>
 ICSlot 2 LOAD_IC UNINITIALIZED
  [8]: 0x3060d045 <Symbol: 711234650 <String[20]: uninitialized_symbol>>
  [9]: 0x3060d045 <Symbol: 711234650 <String[20]: uninitialized_symbol>>
 ICSlot 3 LOAD_IC MONOMORPHIC
  [10]: 0x5dc0d3b5 WeakCell for 0x3a710d71 <Map(FAST_HOLEY_ELEMENTS)>
  [11]: 0x4202af01 <Code: HANDLER>

BUG=

Review URL: https://codereview.chromium.org/1225403005

Cr-Commit-Position: refs/heads/master@{#29679}

src/objects-printer.cc

@@ -503,6 +503,61 @@ void FixedDoubleArray::FixedDoubleArrayPrint(std::ostream& os) {  // NOLINT
 }
 
 
+void TypeFeedbackVector::Print() {
+  OFStream os(stdout);
+  TypeFeedbackVectorPrint(os);
+  os << std::flush;
+}
+
+
+void TypeFeedbackVector::TypeFeedbackVectorPrint(std::ostream& os) {  // NOLINT
+  HeapObject::PrintHeader(os, "TypeFeedbackVector");
+  os << " - length: " << length();
+  if (length() == 0) {
+    os << " (empty)\n";
+    return;
+  }
+
+  os << "\n - ics with type info: " << ic_with_type_info_count();
+  os << "\n - generic ics: " << ic_generic_count();
+
+  if (Slots() > 0) {
+    for (int i = 0; i < Slots(); i++) {
+      FeedbackVectorSlot slot(i);
+      os << "\n Slot " << i << " [" << GetIndex(slot)
+         << "]: " << Brief(Get(slot));
+    }
+  }
+
+  if (ICSlots() > 0) {
+    DCHECK(elements_per_ic_slot() == 2);
+
+    for (int i = 0; i < ICSlots(); i++) {
+      FeedbackVectorICSlot slot(i);
+      Code::Kind kind = GetKind(slot);
+      os << "\n ICSlot " << i;
+      if (kind == Code::LOAD_IC) {
+        LoadICNexus nexus(this, slot);
+        os << " LOAD_IC " << Code::ICState2String(nexus.StateFromFeedback());
+      } else if (kind == Code::KEYED_LOAD_IC) {
+        KeyedLoadICNexus nexus(this, slot);
+        os << " KEYED_LOAD_IC "
+           << Code::ICState2String(nexus.StateFromFeedback());
+      } else {
+        DCHECK(kind == Code::CALL_IC);
+        CallICNexus nexus(this, slot);
+        os << " CALL_IC " << Code::ICState2String(nexus.StateFromFeedback());
+      }
+
+      os << "\n  [" << GetIndex(slot) << "]: " << Brief(Get(slot));
+      os << "\n  [" << (GetIndex(slot) + 1)
+         << "]: " << Brief(get(GetIndex(slot) + 1));
+    }
+  }
+  os << "\n";
+}
+
+
 void JSValue::JSValuePrint(std::ostream& os) {  // NOLINT
   HeapObject::PrintHeader(os, "ValueObject");
   value()->Print(os);
@@ -761,7 +816,7 @@ void SharedFunctionInfo::SharedFunctionInfoPrint(std::ostream& os) {  // NOLINT
   os << "\n - length = " << length();
   os << "\n - optimized_code_map = " << Brief(optimized_code_map());
   os << "\n - feedback_vector = ";
-  feedback_vector()->FixedArrayPrint(os);
+  feedback_vector()->TypeFeedbackVectorPrint(os);
   os << "\n";
 }
 

src/type-feedback-vector.h

@@ -192,6 +192,13 @@ class TypeFeedbackVector : public FixedArray {
   static Handle<TypeFeedbackVector> Copy(Isolate* isolate,
                                          Handle<TypeFeedbackVector> vector);
 
+#ifdef OBJECT_PRINT
+  // For gdb debugging.
+  void Print();
+#endif  // OBJECT_PRINT
+
+  DECLARE_PRINTER(TypeFeedbackVector)
+
   // Clears the vector slots and the vector ic slots.
   void ClearSlots(SharedFunctionInfo* shared) { ClearSlotsImpl(shared, true); }
   void ClearSlotsAtGCTime(SharedFunctionInfo* shared) {

tools/gdbinit

@@ -20,6 +20,15 @@ Print a v8 Code object from an internal code address
 Usage: jco pc
 end
 
+# Print TypeFeedbackVector
+define jfv
+print ((v8::internal::TypeFeedbackVector*)($arg0))->Print()
+end
+document jfv
+Print a v8 TypeFeedbackVector object
+Usage: jtv tagged_ptr
+end
+
 # Print DescriptorArray.
 define jda
 print ((v8::internal::DescriptorArray*)($arg0))->Print()