# HG changeset patch
# User redestad
# Date 1483475765 -3600
# Node ID d4693bf78777bcddf2f724c5592549dc715e55ab
# Parent  077af5bb5fa45cf39e38e05fbd78fbe94d934509
8172169: Re-examine String field optionality
Reviewed-by: kvn, thartmann

diff -r 077af5bb5fa4 -r d4693bf78777 hotspot/src/share/vm/classfile/javaClasses.cpp
--- a/hotspot/src/share/vm/classfile/javaClasses.cpp	Tue Jan 03 17:17:14 2017 +0100
+++ b/hotspot/src/share/vm/classfile/javaClasses.cpp	Tue Jan 03 21:36:05 2017 +0100
@@ -163,8 +163,8 @@
 
   Klass* k = SystemDictionary::String_klass();
   compute_offset(value_offset,           k, vmSymbols::value_name(),  vmSymbols::byte_array_signature());
-  compute_optional_offset(hash_offset,   k, vmSymbols::hash_name(),   vmSymbols::int_signature());
-  compute_optional_offset(coder_offset,  k, vmSymbols::coder_name(),  vmSymbols::byte_signature());
+  compute_offset(hash_offset,            k, vmSymbols::hash_name(),   vmSymbols::int_signature());
+  compute_offset(coder_offset,           k, vmSymbols::coder_name(),  vmSymbols::byte_signature());
 
   initialized = true;
 }
@@ -3977,12 +3977,8 @@
   // java.lang.String
 
   CHECK_OFFSET("java/lang/String", java_lang_String, value, "[B");
-  if (java_lang_String::has_hash_field()) {
-    CHECK_OFFSET("java/lang/String", java_lang_String, hash, "I");
-  }
-  if (java_lang_String::has_coder_field()) {
-    CHECK_OFFSET("java/lang/String", java_lang_String, coder, "B");
-  }
+  CHECK_OFFSET("java/lang/String", java_lang_String, hash, "I");
+  CHECK_OFFSET("java/lang/String", java_lang_String, coder, "B");
 
   // java.lang.Class
 
diff -r 077af5bb5fa4 -r d4693bf78777 hotspot/src/share/vm/classfile/javaClasses.hpp
--- a/hotspot/src/share/vm/classfile/javaClasses.hpp	Tue Jan 03 17:17:14 2017 +0100
+++ b/hotspot/src/share/vm/classfile/javaClasses.hpp	Tue Jan 03 21:36:05 2017 +0100
@@ -81,15 +81,6 @@
   static Handle create_from_platform_dependent_str(const char* str, TRAPS);
   static Handle char_converter(Handle java_string, jchar from_char, jchar to_char, TRAPS);
 
-  static bool has_hash_field()  {
-    assert(initialized, "Must be initialized");
-    return (hash_offset > 0);
-  }
-  static bool has_coder_field()  {
-    assert(initialized, "Must be initialized");
-    return (coder_offset > 0);
-  }
-
   static void set_compact_strings(bool value);
 
   static int value_offset_in_bytes()  {
diff -r 077af5bb5fa4 -r d4693bf78777 hotspot/src/share/vm/classfile/javaClasses.inline.hpp
--- a/hotspot/src/share/vm/classfile/javaClasses.inline.hpp	Tue Jan 03 17:17:14 2017 +0100
+++ b/hotspot/src/share/vm/classfile/javaClasses.inline.hpp	Tue Jan 03 21:36:05 2017 +0100
@@ -30,10 +30,8 @@
 #include "oops/oopsHierarchy.hpp"
 
 void java_lang_String::set_coder(oop string, jbyte coder) {
-  assert(initialized, "Must be initialized");
-  if (coder_offset > 0) {
-    string->byte_field_put(coder_offset, coder);
-  }
+  assert(initialized && (coder_offset > 0), "Must be initialized");
+  string->byte_field_put(coder_offset, coder);
 }
 
 void java_lang_String::set_value_raw(oop string, typeArrayOop buffer) {
@@ -61,15 +59,11 @@
   return java_string->int_field(hash_offset);
 }
 bool java_lang_String::is_latin1(oop java_string) {
-  assert(initialized, "Must be initialized");
+  assert(initialized && (coder_offset > 0), "Must be initialized");
   assert(is_instance(java_string), "must be java_string");
-  if (coder_offset > 0) {
-    jbyte coder = java_string->byte_field(coder_offset);
-    assert(CompactStrings || coder == CODER_UTF16, "Must be UTF16 without CompactStrings");
-    return coder == CODER_LATIN1;
-  } else {
-    return false;
-  }
+  jbyte coder = java_string->byte_field(coder_offset);
+  assert(CompactStrings || coder == CODER_UTF16, "Must be UTF16 without CompactStrings");
+  return coder == CODER_LATIN1;
 }
 int java_lang_String::length(oop java_string) {
   assert(initialized, "Must be initialized");
diff -r 077af5bb5fa4 -r d4693bf78777 hotspot/src/share/vm/opto/graphKit.cpp
--- a/hotspot/src/share/vm/opto/graphKit.cpp	Tue Jan 03 17:17:14 2017 +0100
+++ b/hotspot/src/share/vm/opto/graphKit.cpp	Tue Jan 03 21:36:05 2017 +0100
@@ -4348,20 +4348,16 @@
 }
 
 Node* GraphKit::load_String_coder(Node* ctrl, Node* str) {
-  if (java_lang_String::has_coder_field()) {
-    if (!CompactStrings) {
-      return intcon(java_lang_String::CODER_UTF16);
-    }
-    int coder_offset = java_lang_String::coder_offset_in_bytes();
-    const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
-                                                       false, NULL, 0);
-    const TypePtr* coder_field_type = string_type->add_offset(coder_offset);
-    int coder_field_idx = C->get_alias_index(coder_field_type);
-    return make_load(ctrl, basic_plus_adr(str, str, coder_offset),
-                     TypeInt::BYTE, T_BYTE, coder_field_idx, MemNode::unordered);
-  } else {
-    return intcon(0); // false
+  if (!CompactStrings) {
+    return intcon(java_lang_String::CODER_UTF16);
   }
+  int coder_offset = java_lang_String::coder_offset_in_bytes();
+  const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
+                                                     false, NULL, 0);
+  const TypePtr* coder_field_type = string_type->add_offset(coder_offset);
+  int coder_field_idx = C->get_alias_index(coder_field_type);
+  return make_load(ctrl, basic_plus_adr(str, str, coder_offset),
+                   TypeInt::BYTE, T_BYTE, coder_field_idx, MemNode::unordered);
 }
 
 void GraphKit::store_String_value(Node* ctrl, Node* str, Node* value) {