Author: Leonard Chan Date: 2021-12-03T11:21:20-08:00 New Revision: f178a05f220403f2a9d73c7640bfcc7dc2d7be72
URL: https://github.com/llvm/llvm-project/commit/f178a05f220403f2a9d73c7640bfcc7dc2d7be72 DIFF: https://github.com/llvm/llvm-project/commit/f178a05f220403f2a9d73c7640bfcc7dc2d7be72.diff LOG: [libunwind] Fix unwind_leaffunction test It's possible for this test not to pass if the libc used does not provide unwind info for raise. We can replace it with __builtin_cast, which can lead to a SIGTRAP on x86_64 and a SIGILL on aarch64. Using this alternative, a nop is needed before the __builtin_cast. This is because libunwind incorrectly decrements pc, which can cause pc to jump into the previous function and use the incorrect FDE. Differential Revision: https://reviews.llvm.org/D114818 Added: Modified: libunwind/test/unwind_leaffunction.pass.cpp Removed: ################################################################################ diff --git a/libunwind/test/unwind_leaffunction.pass.cpp b/libunwind/test/unwind_leaffunction.pass.cpp index 2a6d8311e24c7..8ff21dd35449c 100644 --- a/libunwind/test/unwind_leaffunction.pass.cpp +++ b/libunwind/test/unwind_leaffunction.pass.cpp @@ -39,11 +39,17 @@ void signal_handler(int signum) { } __attribute__((noinline)) void crashing_leaf_func(void) { - raise(SIGSEGV); + // libunwind searches for the address before the return address which points + // to the trap instruction. NOP guarantees the trap instruction is not the + // first instruction of the function. + // We should keep this here for other unwinders that also decrement pc. + __asm__ __volatile__("nop"); + __builtin_trap(); } int main(int, char**) { - signal(SIGSEGV, signal_handler); + signal(SIGTRAP, signal_handler); + signal(SIGILL, signal_handler); crashing_leaf_func(); return -2; } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
