8319851: Improve exception logging

Reviewed-by: andrew
Backport-of: 87dfeeb14fdd0fa1648a8bec91b5b713cc2c1b83

hotspot/src/share/vm/classfile/javaClasses.cpp

@@ -1235,14 +1235,13 @@ oop java_lang_Throwable::message(Handle throwable) {
 }
 
 
-// Return Symbol for detailed_message or NULL
-Symbol* java_lang_Throwable::detail_message(oop throwable) {
-  PRESERVE_EXCEPTION_MARK;  // Keep original exception
-  oop detailed_message = java_lang_Throwable::message(throwable);
-  if (detailed_message != NULL) {
-    return java_lang_String::as_symbol(detailed_message, THREAD);
+const char* java_lang_Throwable::message_as_utf8(oop throwable) {
+  oop msg = java_lang_Throwable::message(throwable);
+  const char* msg_utf8 = NULL;
+  if (msg != NULL) {
+    msg_utf8 = java_lang_String::as_utf8_string(msg);
   }
-  return NULL;
+  return msg_utf8;
 }
 
 void java_lang_Throwable::set_message(oop throwable, oop value) {

hotspot/src/share/vm/classfile/javaClasses.hpp

@@ -523,12 +523,12 @@ class java_lang_Throwable: AllStatic {
   static void set_backtrace(oop throwable, oop value);
   // Needed by JVMTI to filter out this internal field.
   static int get_backtrace_offset() { return backtrace_offset;}
-  static int get_detailMessage_offset() { return detailMessage_offset;}
   // Message
+  static int get_detailMessage_offset() { return detailMessage_offset;}
   static oop message(oop throwable);
   static oop message(Handle throwable);
+  static const char* message_as_utf8(oop throwable);
   static void set_message(oop throwable, oop value);
-  static Symbol* detail_message(oop throwable);
   static void print_stack_element(outputStream *st, Handle mirror, int method,
                                   int version, int bci, int cpref);
   static void print_stack_element(outputStream *st, methodHandle method, int bci);

hotspot/src/share/vm/classfile/resolutionErrors.cpp

@@ -33,7 +33,7 @@
 // add new entry to the table
 void ResolutionErrorTable::add_entry(int index, unsigned int hash,
                                      constantPoolHandle pool, int cp_index,
-                                     Symbol* error, Symbol* message)
+                                     Symbol* error, const char* message)
 {
   assert_locked_or_safepoint(SystemDictionary_lock);
   assert(!pool.is_null() && error != NULL, "adding NULL obj");
@@ -64,16 +64,14 @@ void ResolutionErrorEntry::set_error(Symbol* e) {
   _error->increment_refcount();
 }
 
-void ResolutionErrorEntry::set_message(Symbol* c) {
-  assert(c != NULL, "must set a value");
-  _message = c;
-  _message->increment_refcount();
+void ResolutionErrorEntry::set_message(const char* c) {
+  _message = c != NULL ? os::strdup(c) : NULL;
 }
 
 // create new error entry
 ResolutionErrorEntry* ResolutionErrorTable::new_entry(int hash, ConstantPool* pool,
                                                       int cp_index, Symbol* error,
-                                                      Symbol* message)
+                                                      const char* message)
 {
   ResolutionErrorEntry* entry = (ResolutionErrorEntry*)Hashtable<ConstantPool*, mtClass>::new_entry(hash, pool);
   entry->set_cp_index(cp_index);
@@ -87,7 +85,9 @@ void ResolutionErrorTable::free_entry(ResolutionErrorEntry *entry) {
   // decrement error refcount
   assert(entry->error() != NULL, "error should be set");
   entry->error()->decrement_refcount();
-  entry->message()->decrement_refcount();
+  if (entry->message() != NULL) {
+    FREE_C_HEAP_ARRAY(char, entry->message(), mtInternal);
+  }
   Hashtable<ConstantPool*, mtClass>::free_entry(entry);
 }
 

hotspot/src/share/vm/classfile/resolutionErrors.hpp

@@ -39,7 +39,7 @@ class ResolutionErrorTable : public Hashtable<ConstantPool*, mtClass> {
   ResolutionErrorTable(int table_size);
 
   ResolutionErrorEntry* new_entry(int hash, ConstantPool* pool, int cp_index,
-                                  Symbol* error, Symbol* message);
+                                  Symbol* error, const char* message);
   void free_entry(ResolutionErrorEntry *entry);
 
   ResolutionErrorEntry* bucket(int i) {
@@ -56,7 +56,7 @@ class ResolutionErrorTable : public Hashtable<ConstantPool*, mtClass> {
   }
 
   void add_entry(int index, unsigned int hash,
-                 constantPoolHandle pool, int which, Symbol* error, Symbol* message);
+                 constantPoolHandle pool, int cp_index, Symbol* error, const char* error_msg);
 
 
   // find error given the constant pool and constant pool index
@@ -80,7 +80,7 @@ class ResolutionErrorEntry : public HashtableEntry<ConstantPool*, mtClass> {
  private:
   int               _cp_index;
   Symbol*           _error;
-  Symbol*           _message;
+  const char*       _message;
 
  public:
   ConstantPool*      pool() const               { return literal(); }
@@ -91,8 +91,9 @@ class ResolutionErrorEntry : public HashtableEntry<ConstantPool*, mtClass> {
   Symbol*            error() const              { return _error; }
   void               set_error(Symbol* e);
 
-  Symbol*            message() const            { return _message; }
-  void               set_message(Symbol* c);
+  const char*        message() const            { return _message; }
+  // The incoming message is copied to the C-Heap.
+  void               set_message(const char* c);
 
   ResolutionErrorEntry* next() const {
     return (ResolutionErrorEntry*)HashtableEntry<ConstantPool*, mtClass>::next();

hotspot/src/share/vm/classfile/systemDictionary.cpp

@@ -2280,7 +2280,7 @@ bool SystemDictionary::add_loader_constraint(Symbol* class_name,
 // Add entry to resolution error table to record the error when the first
 // attempt to resolve a reference to a class has failed.
 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which,
-                                            Symbol* error, Symbol* message) {
+                                            Symbol* error, const char* message) {
   unsigned int hash = resolution_errors()->compute_hash(pool, which);
   int index = resolution_errors()->hash_to_index(hash);
   {
@@ -2296,7 +2296,7 @@ void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
 
 // Lookup resolution error table. Returns error if found, otherwise NULL.
 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which,
-                                                Symbol** message) {
+                                                const char** message) {
   unsigned int hash = resolution_errors()->compute_hash(pool, which);
   int index = resolution_errors()->hash_to_index(hash);
   {

hotspot/src/share/vm/classfile/systemDictionary.hpp

@@ -549,10 +549,10 @@ class SystemDictionary : AllStatic {
   // Record the error when the first attempt to resolve a reference from a constant
   // pool entry to a class fails.
   static void add_resolution_error(constantPoolHandle pool, int which, Symbol* error,
-                                   Symbol* message);
+                                   const char* message);
   static void delete_resolution_error(ConstantPool* pool);
   static Symbol* find_resolution_error(constantPoolHandle pool, int which,
-                                       Symbol** message);
+                                       const char** message);
 
  protected:
 

hotspot/src/share/vm/interpreter/interpreterRuntime.cpp

@@ -451,11 +451,11 @@ IRT_ENTRY(address, InterpreterRuntime::exception_handler_for_exception(JavaThrea
     // tracing
     if (TraceExceptions) {
       ResourceMark rm(thread);
-      Symbol* message = java_lang_Throwable::detail_message(h_exception());
+      const char* detail_message = java_lang_Throwable::message_as_utf8(h_exception());
       ttyLocker ttyl;  // Lock after getting the detail message
-      if (message != NULL) {
+      if (detail_message != NULL) {
         tty->print_cr("Exception <%s: %s> (" INTPTR_FORMAT ")",
-                      h_exception->print_value_string(), message->as_C_string(),
+                      h_exception->print_value_string(), detail_message,
                       (address)h_exception());
       } else {
         tty->print_cr("Exception <%s> (" INTPTR_FORMAT ")",

hotspot/src/share/vm/oops/constantPool.cpp

@@ -569,13 +569,16 @@ bool ConstantPool::resolve_class_constants(TRAPS) {
   return true;
 }
 
-Symbol* ConstantPool::exception_message(constantPoolHandle this_oop, int which, constantTag tag, oop pending_exception) {
+const char* ConstantPool::exception_message(constantPoolHandle this_oop, int which, constantTag tag, oop pending_exception) {
+  // Note: caller needs ResourceMark
+
   // Dig out the detailed message to reuse if possible
-  Symbol* message = java_lang_Throwable::detail_message(pending_exception);
-  if (message != NULL) {
-    return message;
+  const char* msg = java_lang_Throwable::message_as_utf8(pending_exception);
+  if (msg != NULL) {
+    return msg;
   }
 
+  Symbol* message = NULL;
   // Return specific message for the tag
   switch (tag.value()) {
   case JVM_CONSTANT_UnresolvedClass:
@@ -594,16 +597,16 @@ Symbol* ConstantPool::exception_message(constantPoolHandle this_oop, int which,
     ShouldNotReachHere();
   }
 
-  return message;
+  return message != NULL ? message->as_C_string() : NULL;
 }
 
 void ConstantPool::throw_resolution_error(constantPoolHandle this_oop, int which, TRAPS) {
-  Symbol* message = NULL;
+  ResourceMark rm(THREAD);
+  const char* message = NULL;
   Symbol* error = SystemDictionary::find_resolution_error(this_oop, which, &message);
   assert(error != NULL && message != NULL, "checking");
   CLEAR_PENDING_EXCEPTION;
-  ResourceMark rm;
-  THROW_MSG(error, message->as_C_string());
+  THROW_MSG(error, message);
 }
 
 // If resolution for Class, MethodHandle or MethodType fails, save the exception
@@ -622,7 +625,9 @@ void ConstantPool::save_and_throw_exception(constantPoolHandle this_oop, int whi
     // and OutOfMemoryError, etc, or if the thread was hit by stop()
     // Needs clarification to section 5.4.3 of the VM spec (see 6308271)
   } else if (this_oop->tag_at(which).value() != error_tag) {
-    Symbol* message = exception_message(this_oop, which, tag, PENDING_EXCEPTION);
+    ResourceMark rm(THREAD);
+
+    const char* message = exception_message(this_oop, which, tag, PENDING_EXCEPTION);
     SystemDictionary::add_resolution_error(this_oop, which, error, message);
     this_oop->tag_at_put(which, error_tag);
   } else {

hotspot/src/share/vm/oops/constantPool.hpp

@@ -830,7 +830,7 @@ class ConstantPool : public Metadata {
 
   // Exception handling
   static void throw_resolution_error(constantPoolHandle this_oop, int which, TRAPS);
-  static Symbol* exception_message(constantPoolHandle this_oop, int which, constantTag tag, oop pending_exception);
+  static const char* exception_message(constantPoolHandle this_oop, int which, constantTag tag, oop pending_exception);
   static void save_and_throw_exception(constantPoolHandle this_oop, int which, constantTag tag, TRAPS);
 
  public: