Hello; Finally getting back to this issue I have done some cleanup and adjusted the hotspot gcc.make files to use VARIANT rather than DEBUG_LEVEL.
This version also add support for the "-fsanitize=undefined" undefined behaviour warnings feature when it is available (Clang and GCC 4.9). The code to emit the option has been added for Clang but I haven't yet added test for the option's availability under Clang so currently it will be enabled only for GCC. https://bugs.openjdk.java.net/browse/JDK-8032045 http://cr.openjdk.java.net/~mduigou/JDK-8032045/6/webrev/ Mike On Mar 11 2014, at 05:47 , Magnus Ihse Bursie <magnus.ihse.bur...@oracle.com> wrote: > On 2014-03-11 00:49, Mike Duigou wrote: >> I have updated the patch to respond to Magnus's feedback and to accommodate >> intervening changes to the configure and hotspot make files. >> >> https://bugs.openjdk.java.net/browse/JDK-8032045 >> http://cr.openjdk.java.net/~mduigou/JDK-8032045/3/webrev/ >> >> This version is, hopefully, almost ready to be pushed. > > I have only glanced at the hotspot build changes and can't really say > anything about them. The hotspot team still owns these; I'm cc:ing them now. > > The top-level build changes looks fine. Thank you Mike for cleaning things up! > > /Magnus > >> >> Mike >> >> On Feb 20 2014, at 15:43 , Mike Duigou <mike.dui...@oracle.com> wrote: >> >>> Hello all; >>> >>> This issue is a followon to JDK-8030350 >>> (https://bugs.openjdk.java.net/browse/JDK-8030350) which enhanced the >>> compiler warnings used for compiling native code. The proposed changes >>> principally impact the Linux platform. >>> >>> While 8030350 was focused on compiler warnings which did not impact code >>> generation, this changeset will, for some configurations, change the native >>> code generated and likely change performance. These proposed option changes >>> prevent specific types of relocation table, stack and heap memory >>> corruption in native code. Preventing these types of memory corruption may >>> be useful for finding certain kinds of bugs though and do provide some >>> minimal additional protections against malicious attacks. They aren't, by >>> any means, a substitute for following appropriate secure coding guidelines. >>> >>> The rationale behind the implementation is as follows. For release builds >>> during the initial phase of JDK 9 I would like to enable only compile time >>> checks. This ends up being similar to the warnings in JDK-8030350. These >>> options have no runtime impact on footprint or performance and very minimal >>> additional compile time cost while providing value. **Release builds are >>> not expected to see any performance or footprint change as a result of this >>> changeset** >>> >>> For fast debug builds we can enable linker protections (relro) and static >>> compile time bounds checks (FORTIFY_SOURCE=1). FORTIFY_SOURCE=1 might be >>> moved to the production builds as well because it has no runtime cost or >>> executable size cost. >>> >>> For slow debug builds we can enable full linker protection (at a potential >>> cost in startup time), runtime bounds checks and stack protection >>> (FORTIFY_SOURCE=2 -fprotect-stack-all). We will likely enable >>> -fprotect-stack-strong when available in GCC 4.9 >>> >>> The basis for enabling the additional protections in debug builds is that >>> it will help us find bugs in our native code and we aren't as concerned in >>> debug builds with footprint and performance. Since many developers already >>> do their personal builds in fastdebug or slowdebug mode for testing this >>> will provide good opportunity to shake out any problems with the options >>> while not impacting release builds. Should we find that any of the options >>> provide significant value for their cost we can move them to fastdebug or >>> release. If any of the options prove too costly they can be demoted or >>> removed entirely. >>> >>> https://bugs.openjdk.java.net/browse/JDK-8032045 >>> http://cr.openjdk.java.net/~mduigou/JDK-8032045/2/webrev/ >>> >>> Additional to enabling the various compiler options I attempted to >>> rationalize some of the skew between the various >>> hotspot/make/{platform}/makefiles/gcc.make files while avoiding changing >>> existing behaviour. I have also introduced the new -Og "optimize for >>> debugging" option and there are now an explicit C{XX}_O_FLAG_DEBUG >>> definitions to complement the C{XX}_O_FLAG_{DEBUG|NORM|HI|HIGHEST|NONE} >>> optimization options. >>> >>> Thanks, >>> >>> Mike >
