Use regular map-checks to guard string-length loading.

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 a8d13be89ceb104fa667857c78d25fdf8c0fa1ae..89ea6be009345309f95f50ca7a47b5c98d6ccacd 100644
--- a/src/ia32/stub-cache-ia32.cc
+++ b/src/ia32/stub-cache-ia32.cc
@@ -329,32 +329,28 @@ void StubCompiler::GenerateLoadStringLength(MacroAssembler* masm,
                                             Register receiver,
                                             Register scratch1,
                                             Register scratch2,
-                                            Label* miss,
-                                            bool support_wrappers) {
+                                            Label* miss) {
   Label check_wrapper;
 
   // Check if the object is a string leaving the instance type in the
   // scratch register.
-  GenerateStringCheck(masm, receiver, scratch1, miss,
-                      support_wrappers ? &check_wrapper : miss);
+  GenerateStringCheck(masm, receiver, scratch1, miss, &check_wrapper);
 
   // Load length from the string and convert to a smi.
   __ mov(eax, FieldOperand(receiver, String::kLengthOffset));
   __ ret(0);
 
-  if (support_wrappers) {
-    // Check if the object is a JSValue wrapper.
-    __ bind(&check_wrapper);
-    __ cmp(scratch1, JS_VALUE_TYPE);
-    __ j(not_equal, miss);
+  // Check if the object is a JSValue wrapper.
+  __ bind(&check_wrapper);
+  __ cmp(scratch1, JS_VALUE_TYPE);
+  __ j(not_equal, miss);
 
-    // Check if the wrapped value is a string and load the length
-    // directly if it is.
-    __ mov(scratch2, FieldOperand(receiver, JSValue::kValueOffset));
-    GenerateStringCheck(masm, scratch2, scratch1, miss, miss);
-    __ mov(eax, FieldOperand(scratch2, String::kLengthOffset));
-    __ ret(0);
-  }
+  // Check if the wrapped value is a string and load the length
+  // directly if it is.
+  __ mov(scratch2, FieldOperand(receiver, JSValue::kValueOffset));
+  GenerateStringCheck(masm, scratch2, scratch1, miss, miss);
+  __ mov(eax, FieldOperand(scratch2, String::kLengthOffset));
+  __ ret(0);
 }