/*
+ * Acess2 C++ Support Library
+ * - By John Hodge (thePowersGang)
+ *
+ * exception_handling.cc
+ * - Exception handling code (defined by C++ ABI)
+ *
+ * References:
+ * - LLVM Exception handling
+ * > http://llvm.org/docs/ExceptionHandling.html
+ * - Itanium C++ ABI
+ * >http://mentorembedded.github.io/cxx-abi/abi-eh.html
+ * - HP's "aC++" Document, Ch 7 "Exception Handling Tables"
+ * > http://mentorembedded.github.io/cxx-abi/exceptions.pdf
*/
#include <typeinfo>
#include <cstdint>
+#include <cstddef>
+#include <cstdlib>
+#include <cstring>
+#include <exception>
+#include "exception_handling_cxxabi.h"
-typedef void *(unexpected_handler)(void);
-typedef void *(terminate_handler)(void);
+#include <acess/sys.h>
-struct _Unwind_Context;
+#define DEBUG_ENABLED 1
-typedef enum {
- _URC_NO_REASON = 0,
- _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
- _URC_FATAL_PHASE2_ERROR = 2,
- _URC_FATAL_PHASE1_ERROR = 3,
- _URC_NORMAL_STOP = 4,
- _URC_END_OF_STACK = 5,
- _URC_HANDLER_FOUND = 6,
- _URC_INSTALL_CONTEXT = 7,
- _URC_CONTINUE_UNWIND = 8
-} _Unwind_Reason_Code;
+#if DEBUG_ENABLED
+# define DEBUG(v...) ::_SysDebug(v)
+#else
+# define DEBUG(v...) do{}while(0)
+#endif
-typedef void (*_Unwind_Exception_Cleanup_Fn)(_Unwind_Reason_Code reason, struct _Unwind_Exception *exc);
+/*__thread*/ struct __cxa_eh_globals {
+ __cxa_exception *caughtExceptions;
+ unsigned int uncaughtExceptions;
+} eh_globals;
-struct _Unwind_Exception
-{
- uint64_t exception_class;
- _Unwind_Exception_Cleanup_Fn exception_cleanup;
- uint64_t private_1;
- uint64_t private_2;
-};
-
-struct __cxa_exception
-{
- std::type_info* exceptionType;
- void (*exceptionDestructor)(void *);
- unexpected_handler unexpectedHandler;
- terminate_handler terminateHandler;
- __cxa_exception* nextException;
-
- int handlerCount;
-
- int handlerSwitchValue;
- const char* actionRecord;
- const char* languageSpecificData;
- void* catchTemp;
- void* adjustedPtr;
-
- _Unwind_Exception unwindHeader;
-};
+/*__thread*/ struct {
+ __cxa_exception info;
+ char buf[32];
+} emergency_exception;
+/*__thread*/ bool emergency_exception_used;
- int uncaught_exception_count;
-__cxa_exception *uncaught_exception_top;
+static bool TEST_AND_SET(bool& flag) {
+ bool ret = flag;
+ flag = true;
+ return ret;
+}
+// === CODE ===
+extern "C" __cxa_eh_globals *__cxa_get_globals(void)
+{
+ return &eh_globals;
+}
+extern "C" __cxa_eh_globals *__cxa_get_globals_fast(void)
+{
+ return &eh_globals;
+}
extern "C" void __cxa_call_unexpected(void *)
{
// An unexpected exception was thrown from a function that lists its possible exceptions
+ _SysDebug("__cxa_call_unexpected - TODO");
for(;;);
}
-extern "C" void *__cxa_begin_catch(void *exceptionObject)
+extern "C" void *__cxa_allocate_exception(size_t thrown_size)
+{
+ DEBUG("__cxa_allocate_exception(%i)", thrown_size);
+ __cxa_exception *ret = static_cast<__cxa_exception*>( malloc( sizeof(__cxa_exception) + thrown_size ) );
+ if( !ret ) {
+ if( thrown_size <= sizeof(emergency_exception.buf) && TEST_AND_SET(emergency_exception_used) )
+ {
+ ret = &emergency_exception.info;
+ }
+ }
+ if( !ret ) {
+ _SysDebug("__cxa_allocate_exception - No free space");
+ ::std::terminate();
+ }
+ DEBUG("__cxa_allocate_exception: return %p", ret+1);
+ return ret + 1;
+}
+
+extern "C" void __cxa_free_exception(void *thrown_exception)
+{
+ DEBUG("__cxa_free_exception(%p)", thrown_exception);
+ if(thrown_exception == &emergency_exception.buf) {
+ //assert(emergency_exception_used);
+ emergency_exception_used = false;
+ }
+ else {
+ __cxa_exception *except = static_cast<__cxa_exception*>( thrown_exception ) - 1;
+ free(except);
+ }
+}
+
+extern "C" void __cxa_throw(void *thrown_exception, std::type_info *tinfo, void (*dest)(void*))
{
- struct __cxa_exception *except = static_cast<__cxa_exception*>( exceptionObject );
- except --;
+ #if DEBUG_ENABLED
+ DEBUG("__cxa_throw(%p,%p,%p) '%s' by %p",
+ thrown_exception, tinfo, dest, tinfo->name(), __builtin_return_address(0)
+ );
+ {
+ const ::std::exception* e = reinterpret_cast<const ::std::exception*>(thrown_exception);
+ DEBUG("- e.what() = '%s'", e->what());
+ }
+ #endif
+
+ __cxa_exception *except = static_cast<__cxa_exception*>( thrown_exception ) - 1;
+
+ except->unexpectedHandler = 0;
+ except->terminateHandler = 0;
+ except->exceptionType = tinfo;
+ except->exceptionDestructor = dest;
+ memcpy(&except->unwindHeader.exception_class, EXCEPTION_CLASS_ACESS, 8);
+ __cxa_get_globals()->uncaughtExceptions ++;
+
+ int rv = _Unwind_RaiseException( &except->unwindHeader );
+
+ ::_SysDebug("__cxa_throw(%p,%s) :: UNCAUGHT %i", thrown_exception, tinfo->name(), rv);
+ ::std::terminate();
+}
+
+extern "C" void *__cxa_begin_catch(_Unwind_Exception *exceptionObject)
+{
+ __cxa_exception *except = reinterpret_cast<__cxa_exception*>( exceptionObject+1 )-1;
+ DEBUG("__cxa_begin_catch(%p) - except=%p", exceptionObject, except);
except->handlerCount ++;
- except->nextException = uncaught_exception_top;
- uncaught_exception_top = except;
+ except->nextException = __cxa_get_globals()->caughtExceptions;
+ __cxa_get_globals()->caughtExceptions = except;
- uncaught_exception_count --;
+ __cxa_get_globals_fast()->uncaughtExceptions --;
- return except;
+ return except+1;
}
extern "C" void __cxa_end_catch()
{
- struct __cxa_exception *except = uncaught_exception_top;
+ struct __cxa_exception *except = __cxa_get_globals()->caughtExceptions;
+ DEBUG("__cxa_end_catch - %p", except);
except->handlerCount --;
- uncaught_exception_top = except->nextException;
+ __cxa_get_globals()->caughtExceptions = except->nextException;
if( except->handlerCount == 0 ) {
- //__cxa_free_exception(except+1);
+ __cxa_free_exception(except+1);
}
}
+
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