Mac Arm64 Architecture fpe handling (#3447)

## Summary Handles floating pointing exception when compiled on arch64 and Apple (for M1 and M2 chips). Only works for overflow currently, there is an apparent limitation to these architectures for catching division by zero. ## Additional background SIGILL instead of SIGFPE is needed to catch arch64 signals, see ref: https://developer.apple.com/forums/thread/689159 --------- Co-authored-by: Weiqun Zhang <[email protected]>
AMReX-Codes · Jul 28, 2023 · bba6d9c · bba6d9c
1 parent f41e619
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diff --git a/Docs/sphinx_documentation/source/Debugging.rst b/Docs/sphinx_documentation/source/Debugging.rst
@@ -27,6 +27,7 @@ use of uninitialized values, AMReX also initializes ``FArrayBox``\ s in
 ``MulitFab``\ s and arrays allocated by ``bl_allocate`` to signaling NaNs when it is compiled
 with ``TEST=TRUE`` or ``DEBUG=TRUE`` in GNU make, or with ``-DCMAKE_BUILD_TYPE=Debug`` in CMake.
 One can also control the setting for ``FArrayBox`` using the runtime parameter, ``fab.init_snan``.
+Note for Macs, M1 and M2 chips using Arm64 architecture are not able to trap division by zero.
 
 One can get more information than the backtrace of the call stack by
 instrumenting the code.  Here is an example.

diff --git a/Src/Base/AMReX.cpp b/Src/Base/AMReX.cpp
@@ -102,6 +102,7 @@ namespace system
     int handle_sigint;
     int handle_sigabrt;
     int handle_sigfpe;
+    int handle_sigill;
     int call_addr2line;
     int throw_exception;
     int regtest_reduction;
@@ -127,6 +128,7 @@ namespace {
     SignalHandler prev_handler_sigint  = SIG_ERR; // NOLINT(performance-no-int-to-ptr)
     SignalHandler prev_handler_sigabrt = SIG_ERR; // NOLINT(performance-no-int-to-ptr)
     SignalHandler prev_handler_sigfpe  = SIG_ERR; // NOLINT(performance-no-int-to-ptr)
+    SignalHandler prev_handler_sigill  = SIG_ERR; // NOLINT(performance-no-int-to-ptr)
 #if defined(__linux__)
     int           prev_fpe_excepts = 0;
     int           curr_fpe_excepts = 0;
@@ -329,6 +331,7 @@ amrex::Initialize (int& argc, char**& argv, bool build_parm_parse,
     system::handle_sigint  = 1;
     system::handle_sigabrt = 1;
     system::handle_sigfpe  = 1;
+    system::handle_sigill  = 1;
     system::call_addr2line = 1;
     system::throw_exception = 0;
     system::osout = &a_osout;
@@ -509,6 +512,7 @@ amrex::Initialize (int& argc, char**& argv, bool build_parm_parse,
             pp.queryAdd("handle_sigint" , system::handle_sigint );
             pp.queryAdd("handle_sigabrt", system::handle_sigabrt);
             pp.queryAdd("handle_sigfpe" , system::handle_sigfpe );
+            pp.queryAdd("handle_sigill" , system::handle_sigill );
 
             // We save the singal handlers and restore them in Finalize.
             if (system::handle_sigsegv) {
@@ -566,6 +570,26 @@ amrex::Initialize (int& argc, char**& argv, bool build_parm_parse,
                 }
 #endif
             }
+
+            prev_handler_sigill = SIG_ERR; // NOLINT(performance-no-int-to-ptr)
+            if (system::handle_sigill)
+            {
+#if defined(__APPLE__) && defined(__aarch64__)
+                int invalid = 0, divbyzero=0, overflow=0;
+                pp.queryAdd("fpe_trap_invalid", invalid);
+                pp.queryAdd("fpe_trap_zero", divbyzero);
+                pp.queryAdd("fpe_trap_overflow", overflow);
+
+                fenv_t env;
+                fegetenv(&env);
+                if (invalid)   env.__fpcr |= __fpcr_trap_invalid;
+                if (divbyzero) env.__fpcr |= __fpcr_trap_divbyzero;
+                if (overflow)  env.__fpcr |= __fpcr_trap_overflow;
+                fesetenv(&env);
+                // SIGILL ref: https://developer.apple.com/forums/thread/689159
+#endif
+                prev_handler_sigill = std::signal(SIGILL,  BLBackTrace::handler);
+            }
         }
 
 #ifdef AMREX_USE_HYPRE
@@ -762,6 +786,7 @@ amrex::Finalize (amrex::AMReX* pamrex)
         if (prev_handler_sigint  != SIG_ERR) std::signal(SIGINT , prev_handler_sigint);  // NOLINT(performance-no-int-to-ptr)
         if (prev_handler_sigabrt != SIG_ERR) std::signal(SIGABRT, prev_handler_sigabrt); // NOLINT(performance-no-int-to-ptr)
         if (prev_handler_sigfpe  != SIG_ERR) std::signal(SIGFPE , prev_handler_sigfpe);  // NOLINT(performance-no-int-to-ptr)
+        if (prev_handler_sigill  != SIG_ERR) std::signal(SIGILL , prev_handler_sigill);  // NOLINT(performance-no-int-to-ptr)
 #if defined(__linux__)
 #if !defined(__PGI) || (__PGIC__ >= 16)
         if (curr_fpe_excepts != 0) {

diff --git a/Src/Base/AMReX_BLBackTrace.cpp b/Src/Base/AMReX_BLBackTrace.cpp
@@ -58,6 +58,9 @@ BLBackTrace::handler(int s)
     case SIGFPE:
         amrex::ErrorStream() << "Erroneous arithmetic operation\n";
         break;
+    case SIGILL:
+        amrex::ErrorStream() << "SIGILL Invalid, privileged, or ill-formed instruction\n";
+        break;
     case SIGTERM:
         amrex::ErrorStream() << "SIGTERM\n";
         break;

diff --git a/Tools/CMake/AMReXFlagsTargets.cmake b/Tools/CMake/AMReXFlagsTargets.cmake
@@ -131,6 +131,7 @@ target_compile_options ( Flags_FPE
    $<${_cxx_cray}:-K trap=fp>
    $<${_fortran_clang}:>
    $<${_cxx_clang}:-ftrapv>
+   $<${_cxx_appleclang}:-ftrapv>	
    )
 
 #