RFR 8217647: [backport] JFR: recordings on 32-bit systems unreadable

[Denghui Dong]

Could I have a review of this backport?

Original bug:
  https://bugs.openjdk.java.net/browse/JDK-8217647

Original fix from 11u:
  http://hg.openjdk.java.net/jdk-updates/jdk11u/rev/df5487678893

Webrev: http://cr.openjdk.java.net/~ddong/8217647/webrev.00/

Backport reasons:
1. Fix the unreadable problem on 32-bit in 8u
2. Make subsequent backport more smoothly

The patch cannot apply to 8u cleanly, there are two rejection part and one build failure:

 a) Conflict in jfrRecorderService.cpp. Patch wants this:

-static intptr_t write_checkpoint_event_prologue(JfrChunkWriter& cw, u8 type_id) {
-  const intptr_t prev_cp_offset = cw.previous_checkpoint_offset();
-  const intptr_t prev_cp_relative_offset = 0 == prev_cp_offset ? 0 : prev_cp_offset - cw.current_offset();
+static int64_t write_checkpoint_event_prologue(JfrChunkWriter& cw, u8 type_id) {
+  const int64_t prev_cp_offset = cw.previous_checkpoint_offset();
+  const int64_t prev_cp_relative_offset = 0 == prev_cp_offset ? 0 : prev_cp_offset - cw.current_offset();
   cw.reserve(sizeof(u4));
   cw.write<u8>(EVENT_CHECKPOINT);
   cw.write(JfrTicks::now());
-  cw.write<jlong>((jlong)0);
+  cw.write((int64_t)0);
   cw.write(prev_cp_relative_offset); // write previous checkpoint offset delta
   cw.write<bool>(false); // flushpoint
-  cw.write<u4>((u4)1); // nof types in this checkpoint
-  cw.write<u8>(type_id);
-  const intptr_t number_of_elements_offset = cw.current_offset();
+  cw.write((u4)1); // nof types in this checkpoint
+  cw.write(type_id);
+  const int64_t number_of_elements_offset = cw.current_offset();
   cw.reserve(sizeof(u4));
   return number_of_elements_offset;
 }

 ... but the 8u code is:

static intptr_t write_checkpoint_event_prologue(JfrChunkWriter& cw, u8 type_id) {
  const intptr_t prev_cp_offset = cw.previous_checkpoint_offset();
  const intptr_t prev_cp_relative_offset = 0 == prev_cp_offset ? 0 : prev_cp_offset - cw.current_offset();
  cw.reserve(sizeof(u4));
  cw.write<u8>(EVENT_CHECKPOINT);
  cw.write(JfrTicks::now());
  cw.write<jlong>((jlong)0);
  cw.write<jlong>((jlong)prev_cp_relative_offset); // write previous checkpoint offset delta
  cw.write<bool>(false); // flushpoint
  cw.write<u4>((u4)1); // nof types in this checkpoint
  cw.write<u8>(type_id);
  const intptr_t number_of_elements_offset = cw.current_offset();
  cw.reserve(sizeof(u4));
  return number_of_elements_offset;
}

 ... I did a manual adjustment: 
    cw.write<jlong>((jlong)prev_cp_relative_offset); => cw.write(prev_cp_relative_offset);

 b) Conflict in jfrWriterHost.inline.hpp. Patch wants this:

 template <typename BE, typename IE, typename WriterPolicyImpl>
 inline void WriterHost<BE, IE, WriterPolicyImpl>::write(double value) {
-  be_write(*(uintptr_t*)&(value));
+  be_write(*(u8*)&(value));
 }

 ... but the 8u code is:

template <typename BE, typename IE, typename WriterPolicyImpl>
inline void WriterHost<BE, IE, WriterPolicyImpl>::write(double value) {
  be_write(*(u8*)&(value));
}

 ... so I skipped it.

 c) Build failure. Patch wants this in jfrRepository.cpp:

+            log_info(jfr) ( // For user, should not be "jfr, system"
+              "Unable to recover JFR data");
+            break;

 ... but 8u didn't support unified logging, so I added "if (LogJFR) tty->print_cr("Unable to recover JFR data");"


 d) Other Problem: the original patch(http://hg.openjdk.java.net/jdk/jdk/rev/0abec72a3ac2) also modified jfrChunkRotation.hpp、jfrChunkRotation.cpp and jfrJniMethod.cpp, but the backport patch for 11u ignored them(http://mail.openjdk.java.net/pipermail/jdk-updates-dev/2019-April/000921.html)

Thanks,
Denghui Dong