What does Peter think? For those too young to remember, Peter invented stabs way back when he was a young grad student at Berkeley :-) It has given admirable service, like so much else he has touched!
-- Ramki ysr1729 > On Nov 21, 2014, at 08:30, charlie hunt <[email protected]> wrote: > > Looks good, though I am not an official (R)eviewer. > > Charlie > >> On Nov 21, 2014, at 9:30 AM, Erik Helin <[email protected]> wrote: >> >> Hi all, >> >> this patch changes the debug symbols format on Solaris from STABS >> [0] to DWARF [1] for libjvm.so. Since the supported compiler on Solaris >> has been updated to Oracle Solaris Studio 12.3 [2], the STABS debug format >> is now deprecated in the supported compiler [3]: >> >> -xdebugformat=stabs generates debugging information >> using the stabs standard format. The stabs format is no >> longer supported. >> >> Furthermore, in Oracle Solaris Studio 12.4, the release notes says [4]: >> >> The –xdebugformat=stabs for all compilers might be removed in a future >> release. The only debugger format option will be –xdebugformat=dwarf, >> which is currently the default. >> >> So, it seems to be a good time to change the debug format to DWARF when >> compiling with Oracle Solaris Studio. I also changed the debug format for >> GCC on Solaris to be DWARF, since the STABS support in GCC is in >> maintenance mode [5]. >> >> More reasons for using DWARF instead of STABS are: >> - Better support by Oracle Studio Performance Analyzer (the performance >> team have requested that we use DWARF v2 or later instead of STABS). >> - DWARF provides a better debugging experience for C++ compared to STABS. >> >> The one drawback of using DWARF compared to STABS is that the size of the >> debuginfo increases. For a SPARC fastdebug build the size of >> libjvm.debuginfo built with STABS is 782 MB and with DWARF 1002 MB. >> >> To summarize, we need to change from STABS to DWARF because STABS is >> deprecated in 12.3 (even "more" deprecated 12.4 given the wording in the >> release notes). I would suggest to change sooner rather than later, given >> that the change to DWARF also brings Oracle Studio Performance Analyzer >> support as well as a better C++ debugging experience in dbx. >> >> Webrev: >> http://cr.openjdk.java.net/~ehelin/8065656/webrev.00/ >> >> Bug: >> https://bugs.openjdk.java.net/browse/JDK-8065656 >> >> Testing: >> - Compiled with Oracle Solaris Studio 12.3 on both Solaris 11.1 on SPARC >> and Solaris 11.1 on x86-64 using JPRT. >> - Verified that DWARF v2 symbols are produced with objdump. >> >> Thanks, >> Erik >> >> [0]: http://www.sourceware.org/gdb/onlinedocs/stabs.html >> [1]: http://www.dwarfstd.org/ >> [2]: http://mail.openjdk.java.net/pipermail/jdk9-dev/2014-October/001489.html >> [3]: https://docs.oracle.com/cd/E24457_01/html/E22003/cplusplus.1.html >> [4]: https://docs.oracle.com/cd/E37069_01/html/E37070/gnxfn.html >> [5]: https://sourceware.org/ml/binutils/2013-01/msg00028.html
