8295893: Improve printing of Constant Pool Cache Entries

Reviewed-by: dholmes, coleenp, iklam

src/hotspot/share/oops/cpCache.cpp

@@ -623,31 +623,46 @@ Method* ConstantPoolCacheEntry::get_interesting_method_entry() {
 void ConstantPoolCacheEntry::print(outputStream* st, int index, const ConstantPoolCache* cache) const {
   // print separator
   if (index == 0) st->print_cr("                 -------------");
-  // print entry
+  // print universal entry info
-  st->print("%3d  (" PTR_FORMAT ")  ", index, (intptr_t)this);
+  st->print_cr("%3d", index);
-  st->print_cr("[%02x|%02x|%5d]", bytecode_2(), bytecode_1(),
+  st->print_cr(" - this: " PTR_FORMAT, p2i(this));
-               constant_pool_index());
+  st->print_cr(" - bytecode 1: %s %02x", Bytecodes::name(bytecode_1()), bytecode_1());
-  st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f1);
+  st->print_cr(" - bytecode 2: %s %02x", Bytecodes::name(bytecode_2()), bytecode_2());
-  st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_f2);
+  st->print_cr(" - cp index: %5d", constant_pool_index());
-  st->print_cr("                 [   " PTR_FORMAT "]", (intptr_t)_flags);
+  if (is_method_entry()) {
-
+    ResourceMark rm;
-  if ((bytecode_1() == Bytecodes::_invokehandle ||
-       bytecode_1() == Bytecodes::_invokedynamic)) {
     constantPoolHandle cph(Thread::current(), cache->constant_pool());
     Method* m = method_if_resolved(cph);
-    oop appendix = appendix_if_resolved(cph);
+    st->print_cr(" - F1:  [   " PTR_FORMAT "]", (intptr_t)_f1);
-    ResourceMark rm;
+    st->print_cr(" - F2:  [   " PTR_FORMAT "]", (intptr_t)_f2);
-    if (m != NULL) {
+    st->print_cr(" - method: " INTPTR_FORMAT " %s", p2i(m), m != nullptr ? m->external_name() : nullptr);
-      st->print_cr("  Method%s: " INTPTR_FORMAT " %s.%s%s",
+    st->print_cr(" - flag values: [%02x|0|0|%01x|%01x|%01x|%01x|0|%01x|%01x|00|00|%02x]",
-                   m->is_native() ? " (native)" : "",
+                 flag_state(), has_local_signature(), has_appendix(),
-                   p2i(m),
+                 is_forced_virtual(), is_final(), is_vfinal(),
-                   m->method_holder()->name()->as_C_string(),
+                 indy_resolution_failed(), parameter_size());
-                   m->name()->as_C_string(), m->signature()->as_C_string());
+    st->print_cr(" - tos: %s\n - local signature: %01x\n"
-    }
+                 " - has appendix: %01x\n - forced virtual: %01x\n"
-    if (appendix != NULL) {
+                 " - final: %01x\n - virtual final: %01x\n - resolution failed: %01x\n"
-      st->print("  appendix: ");
+                 " - num parameters: %02x",
-      appendix->print_on(st);
+                 type2name(as_BasicType(flag_state())), has_local_signature(), has_appendix(),
+                 is_forced_virtual(), is_final(), is_vfinal(),
+                 indy_resolution_failed(), parameter_size());
+    if (bytecode_1() == Bytecodes::_invokehandle ||
+        bytecode_1() == Bytecodes::_invokedynamic) {
+      oop appendix = appendix_if_resolved(cph);
+      if (appendix != nullptr) {
+        st->print("  appendix: ");
+        appendix->print_on(st);
+      }
     }
+  } else {
+    assert(is_field_entry(), "must be a field entry");
+    st->print_cr(" - F1:  [   " PTR_FORMAT "]", (intptr_t)_f1);
+    st->print_cr(" - F2:  [   " PTR_FORMAT "]", (intptr_t)_f2);
+    st->print_cr(" - flag values: [%02x|0|1|0|0|0|%01x|%01x|0|0|%04x]",
+                 flag_state(), is_final(), is_volatile(), field_index());
+    st->print_cr(" - tos: %s\n - final: %d\n - volatile: %d\n - field index: %04x",
+                 type2name(as_BasicType(flag_state())), is_final(), is_volatile(), field_index());
   }
   st->print_cr("                 -------------");
 }

test/hotspot/gtest/oops/test_cpCache_output.cpp

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+#include "precompiled.hpp"
+#include "classfile/vmClasses.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/constantPool.hpp"
+#include "oops/cpCache.hpp"
+#include "oops/method.hpp"
+#include "runtime/javaThread.hpp"
+#include "runtime/interfaceSupport.inline.hpp"
+#include "utilities/ostream.hpp"
+#include "unittest.hpp"
+
+// Tests for ConstantPoolCache::print_on() function
+TEST_VM(ConstantPoolCache, print_on) {
+  JavaThread* THREAD = JavaThread::current();
+  ThreadInVMfromNative invm(THREAD);
+  ResourceMark rm;
+  stringStream ss;
+
+  InstanceKlass* klass = vmClasses::System_klass();
+  klass->constants()->cache()->print_on(&ss);
+
+  const char* output = ss.freeze();
+  // method entry test
+  ASSERT_TRUE(strstr(output, "this") != NULL) << "must have \"this\"";
+  ASSERT_TRUE(strstr(output, "bytecode 1:") != NULL) << "must have \"bytecode 1\"";
+  ASSERT_TRUE(strstr(output, "bytecode 2:") != NULL) << "must have \"bytecode 2\"";
+  ASSERT_TRUE(strstr(output, "cp index:") != NULL) << "must have constant pool index";
+  ASSERT_TRUE(strstr(output, "F1:") != NULL) << "must have F1 value";
+  ASSERT_TRUE(strstr(output, "F2:") != NULL) << "must have F2 value";
+  ASSERT_TRUE(strstr(output, "method:") != NULL) << "must have a method";
+  ASSERT_TRUE(strstr(output, "flag values:") != NULL) << "must have a flag";
+  ASSERT_TRUE(strstr(output, "tos:") != NULL) << "must have result type";
+  ASSERT_TRUE(strstr(output, "local signature:") != NULL) << "must have local signature flag";
+  ASSERT_TRUE(strstr(output, "has appendix:") != NULL) << "must have appendix flag";
+  ASSERT_TRUE(strstr(output, "forced virtual:") != NULL) << "must have forced virtual flag";
+  ASSERT_TRUE(strstr(output, "final:") != NULL) << "must have final flag";
+  ASSERT_TRUE(strstr(output, "virtual final:") != NULL) << "must have virtual final flag";
+  ASSERT_TRUE(strstr(output, "resolution failed:") != NULL) << "must have resolution failed flag";
+  ASSERT_TRUE(strstr(output, "num parameters:") != NULL) << "must have number of parameters";
+
+  // field entry test
+  ASSERT_TRUE(strstr(output, "volatile:") != NULL) << "must have volatile flag";
+  ASSERT_TRUE(strstr(output, "field index:") != NULL) << "must have field index";
+}