HSX-24 Backport: code review (round 0) for VMError::report_and_die () dies on bad PC (8015884)

[Daniel D. Daugherty]

Greetings,

I have an HSX-24 backport of the proposed fix for the following bug:

     8015884 runThese crashed with SIGSEGV, hs_err has an error instead
             of stacktrace
     http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8015884
     https://jbs.oracle.com/bugs/browse/JDK-8015884

Here are the (round 0) webrev URLs for the HSX-24 backport:

OpenJDK: http://cr.openjdk.java.net/~dcubed/8015884-webrev/0-hsx24/
Internal: http://javaweb.us.oracle.com/~ddaugher/8015884-webrev/0-hsx24/

Here are the (round 1) webrev URLs for the HSX-25 version for reference:

OpenJDK: http://cr.openjdk.java.net/~dcubed/8015884-webrev/1-hsx25/
Internal: http://javaweb.us.oracle.com/~ddaugher/8015884-webrev/1-hsx25/

The easiest way to review the backport is to download and compare
the two patch files with your favorite file comparison tool:

OpenJDK patch links:
http://cr.openjdk.java.net/~dcubed/8015884-webrev/0-hsx24/8015884_exp_for_hsx24.patch
http://cr.openjdk.java.net/~dcubed/8015884-webrev/1-hsx25/8015884_exp_for_hsx25.patch

Internal patch links:
http://javaweb.us.oracle.com/~ddaugher/8015884-webrev/0-hsx24/8015884_exp_for_hsx24.patch
http://javaweb.us.oracle.com/~ddaugher/8015884-webrev/1-hsx25/8015884_exp_for_hsx25.patch 


For 'diff' oriented people (like me), here's my quick sanity of the two
patch files:
     - diff the patches
     - strip down to line additions and deletions
     - strip out the copyright changes

$ diff 8015884-webrev/1-hsx25/8015884_exp_for_hsx25.patch \
     8015884-webrev/0-hsx24/8015884_exp_for_hsx24.patch \
     | grep '^[<>] [+-] ' | grep -v Copyright
 > -   char fname[32];
 > -   pid_t pid = os::Bsd::gettid();
 > +  char fname[32];
 > +  pid_t pid = os::Bsd::gettid();
 > -   jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
 > +  jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
 > -   if (!_print_ascii_file(fname, st)) {
 > -     st->print("Can not get library information for pid = %d\n", pid);
 > -   }
 > +  if (!_print_ascii_file(fname, st)) {
 > +    st->print("Can not get library information for pid = %d\n", pid);
 > +  }
< +  #ifndef CALL_TEST_FUNC_WITH_WRAPPER_IF_NEEDED
 > +  #ifndef TARGET_OS_FAMILY_windows
< -    NOT_PRODUCT(if (ReplayCompiles) ciReplay::replay(thread);)
< +    if (ReplayCompiles) ciReplay::replay(thread);

The majority of the diffs are for white-space changes in the HSX-24
version where the code no longer exists in the HSX-25 version. The
TARGET_OS_FAMILY_windows diff is for the change made after HSX-25 code
review round 1 which was reviewed via e-mail only. The ReplayCompiles
diff is for an option that doesn't exist in HSX-24.

The remainder is an update to the HSX-25 round 0 code review invite.

Testing:
- test/runtime/6888954/vmerrors.sh has been updated to test for a bad
   data pointer instead of os::signal_raise() and includes a new test
   for a bad function pointer
- (running) JPRT build and test job
- (running) JPRT build and new test only job
- (TBD) Aurora Adhoc vm.quick batch for all platforms in the following
   configs: {Client VM, Server VM} x {fastdebug} x {-Xmixed}

Just to be clear: This fix solves the problem of not getting a
stacktrace when we get a bad PC; it does not solve the underlying
reason why libpthread sent the VM into the weeds.

Gory details are below. As always, comments, questions and
suggestions are welome.

Dan


Gory Details:

The primary bug fixes are:

- the Dl_info struct should only be used if dladdr() has
   returned non-zero (no errors) and always check the dladdr()
   return value
- the Dl_info.dli_sname and Dl_info.dli_saddr fields should
   only be used if non-NULL
- the first two fixes are based on the Solaris dladdr() man page
- make logic consistent between MacOS X, Linux and Solaris:
   - offset is only set when a matching symbol is found (and
     the pointer is non-NULL)
- additional changes to get proper hs_err_pid file generation in non-product
   Win* bits when the following tests are executed:
     -XX:ErrorHandlerTest=N option aka test_error_handler() function
     -XX:+ExecuteInternalVMTests option aka execute_internal_vm_tests() 
function

Cleanup bug fixes are:

- add assert()'s to verify os::dll_address_to_function_name() and
   os::dll_address_to_library_name() contract for 'buf' parameter

- HotSpot style: explicitly check int function return values
   rather that assume conversion to boolean, e.g.

     if (dladdr(...)) {  =>  if (dladdr(...) != 0) {

- consistently compare Dl_info fields against NULL instead of a mix of
   '0', NULL and implied boolean

- the Dl_info.dli_fname and Dl_info.dli_fbase fields are only used if
   non-NULL; this was done for consistency (and paranoia); the Solaris
   man page does not state whether or not NULL is a permitted value for
   these fields

- get rid of redundant "else" statements in modified code - thanks Dmitry!
- cleanup whitespace/indenting in modified code
- switch to PTR_FORMAT in some print calls - thanks Harold!

Test changes:
- update case "12" to test for bad data pointer instead of calling
   os::signal_raise(SIGSEGV)
- add case "13" for bad function pointers
- change VM-side of the test code to issue an ERROR message
   when an unexpected test_num value is passed
- change VM-side of the test code to call ShouldNotReachHere() if
   the code makes it out of the case statement