RFR: 8261397: Try Catch Method Failing to Work When Dividing An Integer By 0

[Gerard Ziemski]

On Wed, 17 Feb 2021 19:06:45 GMT, Gerard Ziemski <gziemski at openjdk.org> wrote:

> On Mac ARM hardware running x86 JDK under Rosetta emulation, a div by 0 instruction causes the VM to crash.
> 
> The proposed fix (a workaround) for hotspot is to add **FPE_FLTINV** to the signal handler.
> 
> The actual fix needs to be done in macOS by Apple as the expected signal type here is **FPE_FLTDIV**
> This issue has been filed with Apple and they are tracking it.

Simple native test case for those curious to try it out for themselves:

/*
 Natively on x86_64 we get:
   sigHandler caught sig: 8, info->si_code: 7 [FPE_INTDIV]
 Under Rossetta on M1 for x86_64 binary we get:
   sigHandler caught sig: 8, info->si_code: 5 [FPE_FLTINV]
 */
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
static void sigHandler(int sig, siginfo_t* info, void* arg) {
  printf("sigHandler caught sig: %d, info->si_code: %d [", sig, info->si_code);
  switch (info->si_code) {
    case FPE_FLTDIV: printf("FPE_FLTDIV");break;
    case FPE_INTDIV: printf("FPE_INTDIV");break;
    case FPE_FLTINV: printf("FPE_FLTINV");break;
    default: printf("???");
  }
  printf("]\n");
  exit(sig);
}
int main(int argc, const char * argv[]) {
  struct sigaction sa;
  sigemptyset(&sa.sa_mask);
  sa.sa_sigaction = sigHandler;
  sa.sa_flags = SA_SIGINFO|SA_RESETHAND;
  sigaction(SIGFPE, &sa, NULL);
  volatile int i = 0;
  volatile int j = 47 / i;
  return j;
}

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PR: https://git.openjdk.java.net/jdk/pull/2615