8004872: Early loading of HashMap and StringValue under -XX:+AggressiveOpts can be removed

Summary: this fix also removes the -XX:+UseStringCache option
Reviewed-by: dholmes, acorn, iklam

src/share/vm/classfile/vmSymbols.hpp

@@ -53,8 +53,6 @@
   template(java_lang_Object,                          "java/lang/Object")                         \
   template(java_lang_Class,                           "java/lang/Class")                          \
   template(java_lang_String,                          "java/lang/String")                         \
-  template(java_lang_StringValue,                     "java/lang/StringValue")                    \
-  template(java_lang_StringCache,                     "java/lang/StringValue$StringCache")        \
   template(java_lang_Thread,                          "java/lang/Thread")                         \
   template(java_lang_ThreadGroup,                     "java/lang/ThreadGroup")                    \
   template(java_lang_Cloneable,                       "java/lang/Cloneable")                      \
@@ -106,7 +104,6 @@
   template(java_util_Vector,                          "java/util/Vector")                         \
   template(java_util_AbstractList,                    "java/util/AbstractList")                   \
   template(java_util_Hashtable,                       "java/util/Hashtable")                      \
-  template(java_util_HashMap,                         "java/util/HashMap")                        \
   template(java_lang_Compiler,                        "java/lang/Compiler")                       \
   template(sun_misc_Signal,                           "sun/misc/Signal")                          \
   template(java_lang_AssertionStatusDirectives,       "java/lang/AssertionStatusDirectives")      \
@@ -367,8 +364,6 @@
   template(offset_name,                               "offset")                                   \
   template(count_name,                                "count")                                    \
   template(hash_name,                                 "hash")                                     \
-  template(frontCacheEnabled_name,                    "frontCacheEnabled")                        \
-  template(stringCacheEnabled_name,                   "stringCacheEnabled")                       \
   template(numberOfLeadingZeros_name,                 "numberOfLeadingZeros")                     \
   template(numberOfTrailingZeros_name,                "numberOfTrailingZeros")                    \
   template(bitCount_name,                             "bitCount")                                 \

src/share/vm/opto/bytecodeInfo.cpp

@@ -297,15 +297,6 @@ bool InlineTree::should_not_inline(ciMethod *callee_method,
     }
   }
 
-  if (UseStringCache) {
-    // Do not inline StringCache::profile() method used only at the beginning.
-    if (callee_method->name() == ciSymbol::profile_name() &&
-        callee_method->holder()->name() == ciSymbol::java_lang_StringCache()) {
-      set_msg("profiling method");
-      return true;
-    }
-  }
-
   // use frequency-based objections only for non-trivial methods
   if (callee_method->code_size() <= MaxTrivialSize) {
     return false;

src/share/vm/runtime/arguments.cpp

@@ -263,6 +263,7 @@ static ObsoleteFlag obsolete_jvm_flags[] = {
   { "UseISM",                        JDK_Version::jdk(8), JDK_Version::jdk(9) },
   { "UsePermISM",                    JDK_Version::jdk(8), JDK_Version::jdk(9) },
   { "UseMPSS",                       JDK_Version::jdk(8), JDK_Version::jdk(9) },
+  { "UseStringCache",                JDK_Version::jdk(8), JDK_Version::jdk(9) },
 #ifdef PRODUCT
   { "DesiredMethodLimit",
                            JDK_Version::jdk_update(7, 2), JDK_Version::jdk(8) },

src/share/vm/runtime/globals.hpp

@@ -2589,9 +2589,6 @@ class CommandLineFlags {
   product(bool, AggressiveOpts, false,                                      \
           "Enable aggressive optimizations - see arguments.cpp")            \
                                                                             \
-  product(bool, UseStringCache, false,                                      \
-          "Enable String cache capabilities on String.java")                \
-                                                                            \
   /* statistics */                                                          \
   develop(bool, CountCompiledCalls, false,                                  \
           "counts method invocations")                                      \

src/share/vm/runtime/thread.cpp

@@ -3490,44 +3490,6 @@ jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
 
     initialize_class(vmSymbols::java_lang_String(), CHECK_0);
 
-    if (AggressiveOpts) {
-      {
-        // Forcibly initialize java/util/HashMap and mutate the private
-        // static final "frontCacheEnabled" field before we start creating instances
-#ifdef ASSERT
-        Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
-        assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
-#endif
-        Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
-        KlassHandle k = KlassHandle(THREAD, k_o);
-        guarantee(k.not_null(), "Must find java/util/HashMap");
-        instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
-        ik->initialize(CHECK_0);
-        fieldDescriptor fd;
-        // Possible we might not find this field; if so, don't break
-        if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
-          k()->java_mirror()->bool_field_put(fd.offset(), true);
-        }
-      }
-
-      if (UseStringCache) {
-        // Forcibly initialize java/lang/StringValue and mutate the private
-        // static final "stringCacheEnabled" field before we start creating instances
-        Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
-        // Possible that StringValue isn't present: if so, silently don't break
-        if (k_o != NULL) {
-          KlassHandle k = KlassHandle(THREAD, k_o);
-          instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
-          ik->initialize(CHECK_0);
-          fieldDescriptor fd;
-          // Possible we might not find this field: if so, silently don't break
-          if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
-            k()->java_mirror()->bool_field_put(fd.offset(), true);
-          }
-        }
-      }
-    }
-
     // Initialize java_lang.System (needed before creating the thread)
     initialize_class(vmSymbols::java_lang_System(), CHECK_0);
     initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);