Usermode/Libraries/libc++.so_src/exception_handling.cc

   1 /*
   2  */
   3 #include <typeinfo>
   4 #include <cstdint>
   5 #include <cstddef>
   6 #include <cstdlib>
   7 #include <cstring>
   8 #include <exception>
   9 #include "exception_handling.h"
  10
  11
  12  int    uncaught_exception_count;
  13 __cxa_exception *uncaught_exception_top;
  14
  15 /*__thread*/ struct {
  16         __cxa_exception info;
  17         char    buf[32];
  18 } emergency_exception;
  19 /*__thread*/ bool       emergency_exception_used;
  20
  21 static bool TEST_AND_SET(bool& flag) {
  22         bool ret = flag;
  23         flag = true;
  24         return ret;
  25 }
  26
  27 // === CODE ===
  28 extern "C" void __cxa_call_unexpected(void *)
  29 {
  30         // An unexpected exception was thrown from a function that lists its possible exceptions
  31         for(;;);
  32 }
  33
  34 extern "C" void *__cxa_allocate_exception(size_t thrown_size)
  35 {
  36         __cxa_exception *ret = static_cast<__cxa_exception*>( malloc( sizeof(__cxa_exception) + thrown_size ) );
  37         if( !ret ) {
  38                 if( thrown_size <= sizeof(emergency_exception.buf) && TEST_AND_SET(emergency_exception_used) )
  39                 {
  40                         ret = &emergency_exception.info;
  41                 }
  42         }
  43         if( !ret ) {
  44                 ::std::terminate();
  45         }
  46         return ret;
  47 }
  48
  49 extern "C" void __cxa_free_exception(void *thrown_exception)
  50 {
  51         if(thrown_exception == &emergency_exception.buf) {
  52                 //assert(emergency_exception_used);
  53                 emergency_exception_used = false;
  54         }
  55         else {
  56                 __cxa_exception *except = static_cast<__cxa_exception*>( thrown_exception ) - 1;
  57                 free(except);
  58         }
  59 }
  60
  61 extern "C" void __cxa_throw(void *thrown_exception, std::type_info *tinfo, void (*dest)(void*))
  62 {
  63         __cxa_exception *except = static_cast<__cxa_exception*>( thrown_exception ) - 1;
  64
  65         except->exceptionType = tinfo;
  66         except->exceptionDestructor = dest;
  67         memcpy(&except->unwindHeader.exception_class, "Ac20C++\0", 8);
  68         uncaught_exception_top ++;
  69
  70         _Unwind_RaiseException(thrown_exception);
  71
  72         ::std::terminate();
  73 }
  74
  75 extern "C" void *__cxa_begin_catch(void *exceptionObject)
  76 {
  77         __cxa_exception *except = static_cast<__cxa_exception*>( exceptionObject ) - 1;
  78
  79         except->handlerCount ++;
  80
  81         except->nextException = uncaught_exception_top;
  82         uncaught_exception_top = except;
  83
  84         uncaught_exception_count --;
  85
  86         return except;
  87 }
  88
  89 extern "C" void __cxa_end_catch()
  90 {
  91         struct __cxa_exception  *except = uncaught_exception_top;
  92         except->handlerCount --;
  93         uncaught_exception_top = except->nextException;
  94
  95         if( except->handlerCount == 0 ) {
  96                 __cxa_free_exception(except+1);
  97         }
  98 }
  99