Do not catch foreign exceptions in Pony try blocks

Closes ponylang#2455.

src/libponyc/codegen/codegen.c

@@ -796,9 +796,9 @@ static void init_runtime(compile_t* c)
   LLVMAddFunctionAttr(value, LLVMNoReturnAttribute);
 #endif
 
-  // i32 pony_personality_v0(...)
+  // i32 ponyint_personality_v0(...)
   type = LLVMFunctionType(c->i32, NULL, 0, true);
-  c->personality = LLVMAddFunction(c->module, "pony_personality_v0", type);
+  c->personality = LLVMAddFunction(c->module, "ponyint_personality_v0", type);
 
   // i32 memcmp(i8*, i8*, intptr)
   params[0] = c->void_ptr;

src/libponyrt/lang/except_try_catch.ll

@@ -4,9 +4,9 @@
 ; compatibility, please try to keep this file as minimal as possible in order
 ; to minimise the chances of breakage with newer LLVM versions.
 
-declare i32 @pony_personality_v0(...)
+declare i32 @ponyint_personality_v0(...)
 
-define i1 @pony_try(void (i8*)* %fun, i8* %ctx) personality i32 (...)* @pony_personality_v0 {
+define i1 @pony_try(void (i8*)* %fun, i8* %ctx) personality i32 (...)* @ponyint_personality_v0 {
 entry:
   invoke void %fun(i8* %ctx)
     to label %post unwind label %unwind

src/libponyrt/lang/posix_except.c

@@ -7,13 +7,15 @@
 #include <unwind.h>
 #include <stdlib.h>
 
-PONY_EXTERN_C_BEGIN
-
 #ifdef PLATFORM_IS_ARM
 #include <string.h>
-#include <stdio.h>
+#define PONY_EXCEPTION_CLASS "Pony\0\0\0\0"
+#else
+#define PONY_EXCEPTION_CLASS 0x506F6E7900000000 // "Pony"
 #endif
 
+PONY_EXTERN_C_BEGIN
+
 static __pony_thread_local struct _Unwind_Exception exception;
 static __pony_thread_local uintptr_t landing_pad;
 
@@ -27,9 +29,9 @@ static void exception_cleanup(_Unwind_Reason_Code reason,
 PONY_API void pony_error()
 {
 #ifdef PLATFORM_IS_ARM
-  memcpy(exception.exception_class, "Pony\0\0\0\0", 8);
+  memcpy(exception.exception_class, PONY_EXCEPTION_CLASS, 8);
 #else
-  exception.exception_class = 0x506F6E7900000000; // "Pony"
+  exception.exception_class = PONY_EXCEPTION_CLASS;
 #endif
   exception.exception_cleanup = exception_cleanup;
   _Unwind_RaiseException(&exception);
@@ -59,12 +61,15 @@ static _Unwind_Reason_Code continue_unwind(_Unwind_Exception* exception,
   return _URC_CONTINUE_UNWIND;
 }
 
-PONY_API _Unwind_Reason_Code pony_personality_v0(_Unwind_State state,
+PONY_API _Unwind_Reason_Code ponyint_personality_v0(_Unwind_State state,
   _Unwind_Exception* exception, _Unwind_Context* context)
 {
   if(exception == NULL || context == NULL)
     return _URC_FAILURE;
 
+  if(memcmp(exception->exception_class, PONY_EXCEPTION_CLASS, 8) != 0)
+    return continue_unwind(exception, context);
+
   // Save exception in r12.
   _Unwind_SetGR(context, 12, (uintptr_t)exception);
 
@@ -116,15 +121,16 @@ PONY_API _Unwind_Reason_Code pony_personality_v0(_Unwind_State state,
 
 #else
 
-PONY_API _Unwind_Reason_Code pony_personality_v0(int version,
+PONY_API _Unwind_Reason_Code ponyint_personality_v0(int version,
   _Unwind_Action actions, uint64_t ex_class,
   struct _Unwind_Exception* exception, struct _Unwind_Context* context)
 {
-  (void)ex_class;
-
   if(version != 1 || exception == NULL || context == NULL)
     return _URC_FATAL_PHASE1_ERROR;
 
+  if(ex_class != PONY_EXCEPTION_CLASS)
+    return _URC_CONTINUE_UNWIND;
+
   // The search phase sets up the landing pad.
   if(actions & _UA_SEARCH_PHASE)
   {

src/libponyrt/lang/win_except.c

@@ -77,13 +77,15 @@ PONY_API void pony_error()
  *  RtlUnwindEx does not ever return to its caller (i.e. this personality
  *  function). If it does, the process will (most likely) be terminated.
  */
-PONY_API EXCEPTION_DISPOSITION pony_personality_v0(EXCEPTION_RECORD *ExcRecord,
-  void* EstablisherFrame, _CONTEXT *ContextRecord, DISPATCHER_CONTEXT* DispatcherContext)
+PONY_API EXCEPTION_DISPOSITION ponyint_personality_v0(
+  EXCEPTION_RECORD *ExcRecord, void* EstablisherFrame, _CONTEXT *ContextRecord,
+  DISPATCHER_CONTEXT* DispatcherContext)
 {
-  if(ExcRecord->ExceptionCode != PONY_EXCEPTION_CLASS || IS_UNWINDING(ExcRecord->ExceptionFlags))
+  if((ExcRecord->ExceptionCode != PONY_EXCEPTION_CLASS) ||
+    IS_UNWINDING(ExcRecord->ExceptionFlags))
     return ExceptionContinueSearch;
 
-  if(!(ExcRecord->ExceptionFlags  &
+  if(!(ExcRecord->ExceptionFlags &
     (EXCEPTION_UNWINDING | EXCEPTION_EXIT_UNWIND)))
   {
     if(!ponyint_lsda_scan(DispatcherContext, &landing_pad))

test/libponyc/codegen.cc

@@ -473,3 +473,48 @@ EXPORT_SYMBOL char test_custom_serialisation_compare(uint64_t* p1, uint64_t* p2)
 }
 
 }
+
+
+TEST_F(CodegenTest, TryBlockCantCatchCppExcept)
+{
+  const char* src =
+    "actor Main\n"
+    "  new create(env: Env) =>\n"
+    "    let r = @codegen_test_tryblock_catch[I32](this~tryblock())\n"
+    "    @pony_exitcode[I32](r)\n"
+
+    "  fun @tryblock() =>\n"
+    "    try\n"
+    "      @codegen_test_tryblock_throw[None]()?\n"
+    "    else\n"
+    "      None\n"
+    "    end";
+
+  TEST_COMPILE(src);
+
+  int exit_code = 0;
+  ASSERT_TRUE(run_program(&exit_code));
+  ASSERT_EQ(exit_code, 1);
+}
+
+
+extern "C"
+{
+
+EXPORT_SYMBOL int codegen_test_tryblock_catch(void (*callback)())
+{
+  try
+  {
+    callback();
+    return 0;
+  } catch(std::exception const&) {
+    return 1;
+  }
+}
+
+EXPORT_SYMBOL bool codegen_test_tryblock_throw()
+{
+  throw std::exception{};
+}
+
+}

test/libponyrt/lang/error.cc

@@ -3,6 +3,8 @@
 
 #include <pony.h>
 
+#include <exception>
+
 TEST(ErrorTest, PonyTry)
 {
   auto cb_success = [](void*){};
@@ -11,3 +13,10 @@ TEST(ErrorTest, PonyTry)
   ASSERT_TRUE(pony_try(cb_success, nullptr));
   ASSERT_FALSE(pony_try(cb_error, nullptr));
 }
+
+TEST(ErrorTest, PonyTryCantCatchCppExcept)
+{
+  auto cb_cppthrow = [](void*){ throw std::exception{}; };
+
+  ASSERT_THROW((pony_try(cb_cppthrow, nullptr)), std::exception);
+}