compiler-rt/test/msan/Linux/signal_mcontext2.cpp

   1 // RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s
   2
   3 // musl does not define FP_XSTATE_MAGIC1.
   4 // REQUIRES: x86_64-target-arch && glibc-2.27
   5
   6 #include <pthread.h>
   7 #include <signal.h>
   8 #include <stdint.h>
   9 #include <ucontext.h>
  10
  11 void handler(int sig, siginfo_t *info, void *uctx) {
  12   volatile int uninit;
  13   auto *mctx = &static_cast<ucontext_t *>(uctx)->uc_mcontext;
  14   auto *fpregs = mctx->fpregs;
  15   // The member names differ across header versions, but the actual layout
  16   // is always the same.  So avoid using members, just use arithmetic.
  17   const uint32_t *after_xmm =
  18       reinterpret_cast<const uint32_t *>(fpregs + 1) - 24;
  19   if (after_xmm[12] == FP_XSTATE_MAGIC1)
  20     reinterpret_cast<_xstate *>(mctx->fpregs)->ymmh.ymmh_space[0] = uninit;
  21   else
  22     mctx->gregs[REG_RAX] = uninit;
  23 }
  24
  25 int main(int argc, char **argv) {
  26   struct sigaction act = {};
  27   act.sa_sigaction = handler;
  28   act.sa_flags = SA_SIGINFO;
  29   sigfillset(&act.sa_mask);
  30   sigaction(SIGPROF, &act, 0);
  31   pthread_kill(pthread_self(), SIGPROF);
  32   return 0;
  33 }
  34
  35 // CHECK: WARNING: MemorySanitizer: