Fix stack unwinding for sparc64; makes C++ exceptions work; ok kettenis@ sthen@

lang/gcc/4.9/Makefile

@@ -1,10 +1,10 @@
-# $OpenBSD: Makefile,v 1.64 2018/12/17 14:05:21 pascal Exp $
+# $OpenBSD: Makefile,v 1.65 2019/02/06 06:48:02 otto Exp $
 
 ONLY_FOR_ARCHS = ${GCC49_ARCHS}
 DPB_PROPERTIES = parallel
 
 V = 4.9.4
-REVISION = 15
+REVISION = 16
 FULL_VERSION = $V
 FULL_PKGVERSION = $V
 

lang/gcc/4.9/patches/patch-libgcc_unwind-dw2_c

@@ -0,0 +1,53 @@
+$OpenBSD: patch-libgcc_unwind-dw2_c,v 1.1 2019/02/06 06:48:02 otto Exp $
+
+Index: libgcc/unwind-dw2.c
+--- libgcc/unwind-dw2.c.orig
++++ libgcc/unwind-dw2.c
+@@ -217,6 +217,25 @@ _Unwind_IsExtendedContext (struct _Unwind_Context *con
+   return (ASSUME_EXTENDED_UNWIND_CONTEXT
+ 	  || (context->flags & EXTENDED_CONTEXT_BIT));
+ }
++
++#ifdef __sparc64__
++
++/* Figure out StackGhost cookie.  */
++_Unwind_Word uw_get_wcookie(void);
++
++asm(".text\n"
++    "uw_get_wcookie:\n"
++    "	add  %o7, %g0, %g4\n"
++    "	save %sp, -176, %sp\n"
++    "	save %sp, -176, %sp\n"
++    "	flushw\n"
++    "	restore\n"
++    "	ldx [%sp + 2047 + 120], %g5\n"
++    "	xor %g4, %g5, %i0\n"
++    "	ret\n"
++    "	 restore\n");
++#endif
++
+ 
+ /* Get the value of register INDEX as saved in CONTEXT.  */
+ 
+@@ -239,6 +258,13 @@ _Unwind_GetGR (struct _Unwind_Context *context, int in
+   if (_Unwind_IsExtendedContext (context) && context->by_value[index])
+     return _Unwind_Get_Unwind_Word (val);
+ 
++#ifdef __sparc64__
++  /* _Unwind_Word and _Unwind_Ptr are the same size on sparc64 */
++  _Unwind_Word reg = * (_Unwind_Word *) val;
++  if (index == 15 || index == 31) 
++    reg ^= uw_get_wcookie ();
++  return reg;
++#else
+   /* This will segfault if the register hasn't been saved.  */
+   if (size == sizeof(_Unwind_Ptr))
+     return * (_Unwind_Ptr *) (_Unwind_Internal_Ptr) val;
+@@ -247,6 +273,7 @@ _Unwind_GetGR (struct _Unwind_Context *context, int in
+       gcc_assert (size == sizeof(_Unwind_Word));
+       return * (_Unwind_Word *) (_Unwind_Internal_Ptr) val;
+     }
++#endif
+ }
+ 
+ static inline void *