Introduce extra IC state to record additional feedback from IC-s.

src/ia32/stub-cache-ia32.cc

Index: src/ia32/stub-cache-ia32.cc
diff --git a/src/ia32/stub-cache-ia32.cc b/src/ia32/stub-cache-ia32.cc
index bcb02ed7970558b298971f092ae012cd10c20c79..23ea7116da7e76b24c0ff178fbade812d7dfe215 100644
--- a/src/ia32/stub-cache-ia32.cc
+++ b/src/ia32/stub-cache-ia32.cc
@@ -1361,12 +1361,13 @@ void CallStubCompiler::GenerateLoadFunctionFromCell(JSGlobalPropertyCell* cell,
 }
 
 
-MaybeObject* CallStubCompiler::GenerateMissBranch() {
+MaybeObject* CallStubCompiler::GenerateBranchHelper(
+    Code::ExtraICState extra_ic_state) {
+  MaybeObject* maybe_obj = StubCache::ComputeCallMiss(arguments().immediate(),
+                                                      kind_,
+                                                      extra_ic_state);
   Object* obj;
-  { MaybeObject* maybe_obj =
-        StubCache::ComputeCallMiss(arguments().immediate(), kind_);
-    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
-  }
+  if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   __ jmp(Handle<Code>(Code::cast(obj)), RelocInfo::CODE_TARGET);
   return obj;
 }
@@ -1724,8 +1725,18 @@ MaybeObject* CallStubCompiler::CompileStringCharCodeAtCall(
   char_code_at_generator.GenerateSlow(masm(), call_helper);
 
   __ bind(&index_out_of_range);
-  __ Set(eax, Immediate(Factory::nan_value()));
-  __ ret((argc + 1) * kPointerSize);
+  // Restore function name in ecx.
+  __ Set(ecx, Immediate(Handle<String>(name)));
+  if (kind_ == Code::CALL_IC && extra_ic_state_ == DEFAULT_STRING_STUB) {
+    // Change the extra state to record the fact that we've seen an
+    // out of bounds index.
+    MaybeObject* maybe_obj =
+        GenerateExtraStateChangeBranch(STRING_INDEX_OUT_OF_BOUNDS);
+    if (maybe_obj->IsFailure()) return maybe_obj;
+  } else {
+    __ Set(eax, Immediate(Factory::nan_value()));
+    __ ret((argc + 1) * kPointerSize);
+  }
 
   __ bind(&miss);
   Object* obj;
@@ -1799,8 +1810,18 @@ MaybeObject* CallStubCompiler::CompileStringCharAtCall(
   char_at_generator.GenerateSlow(masm(), call_helper);
 
   __ bind(&index_out_of_range);
-  __ Set(eax, Immediate(Factory::empty_string()));
-  __ ret((argc + 1) * kPointerSize);
+  // Restore function name in ecx.
+  __ Set(ecx, Immediate(Handle<String>(name)));
+  if (kind_ == Code::CALL_IC && extra_ic_state_ == DEFAULT_STRING_STUB) {
+    // Change the extra state to record the fact that we've seen an
+    // out of bounds index.
+    MaybeObject* maybe_obj =
+        GenerateExtraStateChangeBranch(STRING_INDEX_OUT_OF_BOUNDS);
+    if (maybe_obj->IsFailure()) return maybe_obj;
+  } else {
+    __ Set(eax, Immediate(Factory::empty_string()));
+    __ ret((argc + 1) * kPointerSize);
+  }
 
   __ bind(&miss);
   Object* obj;