Hello, This was built using the gcc in unstable (gcc-8_8.2.0-6). I will upload a new version later (and upload the source packages).
Doko, does it ring a bell? And I agree that I should move to a two stages build (yeah, more compilation time!) Cheers, Sylvestre Le 20/09/2018 à 06:43, Mike Hommey a écrit : > Package: clang-7 > Version: 1:7-1 > Severity: normal > > Dear Maintainer, > > Using a clang plugin that creates a MatchFinder crashes. One way to > reproduce is to get the Firefox source code from > https://hg.mozilla.org/mozilla-central, create a .mozconfig file with > the following contents: > ac_add_options --enable-clang-plugin > ac_add_options CC=clang-7 > ac_add_options LLVM_CONFIG=llvm-config-7 > > and run ./mach build > > This results in the compiler crashing when it uses the plugin. > > The constructor C++ code is: > > MatchFinder::MatchFinder(MatchFinderOptions Options) > : Options(std::move(Options)), ParsingDone(nullptr) {} > > where MatchFinderOptions is defined as: > > struct MatchFinderOptions { > struct Profiling { > Profiling(llvm::StringMap<llvm::TimeRecord> &Records) > : Records(Records) {} > > /// Per bucket timing information. > llvm::StringMap<llvm::TimeRecord> &Records; > }; > > /// Enables per-check timers. > /// > /// It prints a report after match. > llvm::Optional<Profiling> CheckProfiling; > }; > > I won't go on detailing how Optional is defined, but the point is > MatchFinderOptions, and thus the Optional is passed by value. > > But the function as it appears in the clang-7 executable looks like: > > lea 0xb0(%rdi),%rax > movq $0x0,(%rdi) > mov %rax,0x90(%rdi) > mov %rax,0x98(%rdi) > movzbl 0x8(%rsi),%eax > movq $0x0,0x8(%rdi) > movq $0x0,0x10(%rdi) > movq $0x0,0x18(%rdi) > movq $0x0,0x20(%rdi) > (...) > mov %al,0x138(%rdi) > test %al,%al > je > <_ZN5clang12ast_matchers11MatchFinderC2ENS1_18MatchFinderOptionsE+215> > mov (%rsi),%rax > mov %rax,0x130(%rdi) > movq $0x0,0x140(%rdi) > retq > > The crashing instruction is the movzbl, which tries to dereference %rsi > as a pointer, and its value is 0. What's happening here, essentially, is > that it's compiled with the assumption that %rsi is a pointer to the > MatchFinderOptions. That's clearly not what's supposed to happen given > the C++ code. > > As bootstrapped by clang-7 itself, the same function is compiled as > lea 0xb0(%rdi),%rax > xorps %xmm0,%xmm0 > movups %xmm0,0x80(%rdi) > (...) > movups %xmm0,(%rdi) > mov %rax,0x90(%rdi) > mov %rax,0x98(%rdi) > movq $0x10,0xa0(%rdi) > movl $0x0,0xa8(%rdi) > mov %rsi,0x130(%rdi) > mov %dl,0x138(%rdi) > movq $0x0,0x140(%rdi) > retq > > which is compiled with the assumption that %rsi and %rdx (really %rdl) > represent the value of the MatchFinderOptions. > > Interestingly, there's already a #ifdef in Optional.h in llvm to disable > some code for GCC because it miscompiles it. It looks like things got > worse. > > It feels like the clang package should be bootstrapped in 2 stages... > > I'd file a GCC upstream bug for the miscompilation, but as the package > wasn't built on buildds, buildd.debian.org doesn't contain logs that > could tell me what specific version was used. > > Mike > > -- System Information: > Debian Release: buster/sid > APT prefers unstable-debug > APT policy: (500, 'unstable-debug'), (500, 'unstable'), (500, 'testing'), > (1, 'experimental-debug'), (1, 'experimental') > Architecture: amd64 (x86_64) > Foreign Architectures: i386 > > Kernel: Linux 4.17.0-1-amd64 (SMP w/4 CPU cores) > Locale: LANG=ja_JP.UTF-8, LC_CTYPE=ja_JP.UTF-8 (charmap=UTF-8), > LANGUAGE=ja_JP.UTF-8 (charmap=UTF-8) > Shell: /bin/sh linked to /bin/dash > Init: systemd (via /run/systemd/system) > LSM: AppArmor: enabled > > Versions of packages clang-7 depends on: > ii binutils 2.31.1-4 > ii libc6 2.27-5 > ii libc6-dev 2.27-5 > ii libclang-common-7-dev 1:7-1 > ii libclang1-7 1:7-1 > ii libgcc-8-dev 8.2.0-3 > ii libgcc1 1:8.2.0-3 > ii libllvm7 1:7-1 > ii libobjc-8-dev 8.2.0-3 > ii libstdc++-8-dev 8.2.0-3 > ii libstdc++6 8.2.0-3 > > Versions of packages clang-7 recommends: > ii libomp-dev 6.0.1-1 > ii llvm-7-dev 1:7-1 > ii python 2.7.15-3 > > Versions of packages clang-7 suggests: > pn clang-7-doc <none> > > -- no debconf information >
