On 20/12/2019 01:43, John McCall wrote: > On 19 Dec 2019, at 16:27, Adhemerval Zanella wrote: > > On 19/12/2019 14:41, Adhemerval Zanella wrote: > > On 18/12/2019 14:24, John McCall wrote: > > On 18 Dec 2019, at 6:48, Adhemerval Zanella wrote: > > On 18/12/2019 04:16, John McCall wrote: > > There’s been an ongoing failure on the > clang-cmake-armv8-selfhost builder for the last day or so; see e.g.: > > http://lab.llvm.org:8011/builders/clang-cmake-armv7-selfhost/builds/2827/ > > This list is recorded as the contact information for that > builder. > > It is apparently crashing in a tblgen backend that I just > added: > > ``` > Stack dump: > 0. Program arguments: > /home/buildslave/buildslave/clang-cmake-armv7-selfhost/stage1/bin/clang-tblgen > -gen-clang-type-writer -I > /home/buildslave/buildslave/clang-cmake-armv7-selfhost/llvm/clang/include -I > /home/buildslave/buildslave/clang-cmake-armv7-selfhost/llvm/clang/include/clang/AST > -I /home/buildslave/buildslave/clang-cmake-armv7-selfhost/llvm/llvm/include > /home/buildslave/buildslave/clang-cmake-armv7-selfhost/llvm/clang/include/clang/AST/TypeProperties.td > --write-if-changed -o > /home/buildslave/buildslave/clang-cmake-armv7-selfhost/stage1/tools/clang/include/clang/AST/AbstractTypeWriter.inc > Segmentation fault (core dumped) > ``` > > I would like to fix this, but I have no ability to > reproduce it, and the crash information in the log is quite minimal. Is > there a way I can get a shell on a system that can reproduce this, or at the > very least get a line number for where exactly it is crashing? > > John. > > Hi John, > > I am the one responsible for babysitting the bots this week > and I will > take a look at this issue. I will let you know what I found. > > Thanks. > > John. > > Hi John, > > I couldn't reproduce the issue on the bot with > 2f932b57296a573454d29893eedbeaa6901c2a68, > both stage1 and stage2 build fine and check showed no regression. I > restarted the bot > and I will let you know how the results of the next iterations comes > out. > > Hi again John, > > I was looking at a different bot, so the results were for the one running > on armv7 > instead the one that is failing which runs on armv8. > > The problem seems to be in fact a compiler issue on the container we use > to run > buildbot. It is an ubuntu 16.04, but we don't use the default compiler > (gcc 5.4.0), > but instead an updated one (gcc 7.4.0) provided by ubuntu test ppa [1]. > > If I build clang-tblgen with gcc 7.4.0 on Release mode it generates a > segmentation > fault. It does not occur with RelWithDebugInfo neither if I used gcc > 5.4.0 on > Release mode. > > Trying to analyse the core generated does not really give us much > information, it > shows a recursive call on visitASTNodeHierarchyImpl: > > #0 __GI_memcmp (s1=<optimized out>, s2=<optimized out>, len=<optimized > out>) at memcmp.c:352 > #1 0x0001dab8 in > clang::tblgen::visitASTNodeHierarchyImpl(llvm::RecordKeeper&, > llvm::StringRef, llvm::function_ref<void (clang::tblgen::ASTNode, > clang::tblgen::ASTNode)>) () > [...] > > gdb can't show the bottom of the stack. > > This memcmp must be from |StringRef::operator<|. If that were getting > consistently miscompiled, I think we’d be having serious problems throughout > the compiler. But there could be something specific to this function that’s > either provoking a miscompile or just violating language rules; I don’t see > what that would be, though. > > John.
My guess this is specific issue that in fact might be fixed on gcc-7 (I need to check which version the ppa repository actually use). I test with gcc 5.4 and now I am testing with gcc 8. Most likely we will update the stage1 compiler on this bot. _______________________________________________ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org https://lists.linaro.org/mailman/listinfo/linaro-toolchain
