Allow the unwind functions int libgcc_s to interact correctly with libthr.

_Unwind_ForcedUnwind in libgcc_s takes as one of it's parameters a stop
function to tell it when to stop unwinding. One of the stop function's
parameters is a _Unwind_Exception_Class. On most architectures this is an
int64_t, however on ARM EABI the gcc developers have made this a char array
with 8 items. While both of these take the same space they are passed into
the stop function differently, an int64_t is passed in in registers r2 and
r3, while the char[8] is passed in as a pointer to the first item in
register r2.

Because libthr expects the value to be an int64_t we would get incorrect
results when it passes a function that take an int64_t but libgcc passes in
a pointer to a char array including crashing.

The fix is to update libgcc_s to make it pass an int64_t to the stop
function and to libstdc++ as it expects _Unwind_Exception_Class to be an
array.

1 files changed, 2 insertions, 2 deletions

diff --git a/contrib/gcc/config/arm/unwind-arm.h b/contrib/gcc/config/arm/unwind-arm.h
index a3040d7..0811f2c 100644
--- a/contrib/gcc/config/arm/unwind-arm.h
+++ b/contrib/gcc/config/arm/unwind-arm.h
@@ -87,7 +87,7 @@ extern "C" {
 
   struct _Unwind_Control_Block
     {
-      char exception_class[8];
+      unsigned  exception_class __attribute__((__mode__(__DI__)));
       void (*exception_cleanup)(_Unwind_Reason_Code, _Unwind_Control_Block *);
       /* Unwinder cache, private fields for the unwinder's use */
       struct
@@ -186,7 +186,7 @@ extern "C" {
 
   /* Support functions for the PR.  */
 #define _Unwind_Exception _Unwind_Control_Block
-  typedef char _Unwind_Exception_Class[8];
+  typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));
 
   void * _Unwind_GetLanguageSpecificData (_Unwind_Context *);
   _Unwind_Ptr _Unwind_GetRegionStart (_Unwind_Context *);