svn commit: r324760 - stable/11/contrib/gcc/config/arm

[Ian Lepore]

Author: ian
Date: Thu Oct 19 17:26:26 2017
New Revision: 324760
URL: https://svnweb.freebsd.org/changeset/base/324760

Log:
  MFC r323997-r323998
  
  r323997:
  Fix handling of uncaught exceptions in a std::terminate() handler on arm.
  
  When raising an exception, the unwinder searches for a catch handler and if
  none is found it should invoke std::terminate() with the uncaught exception
  as the "current" exception.  Before this change, the terminate handler was
  invoked with no exception as current (abi::__cxa_current_exception_type()
  returned NULL), because the return value from the unwinder indicated an
  internal failure in unwinding.  It turns out that was because all errors
  from get_eit_entry() were translated to _URC_FAILURE.  Now the error is
  returned untranslated, which allows _URC_END_OF_STACK to percolate upwards
  to throw_exception() in libcxxrt.  When it sees that return status it
  properly calls std::terminate() with the uncaught exception installed
  as the current exception, allowing custom terminate handlers to work
  with it.
  
  r323998:
  Fix the return value from _Unwind_Backtrace() on arm.
  
  If unwinding stops due to hitting the end of the call chain, the return
  value is supposed to be _URC_END_OF_STACK; other values indicate internal
  errors.  The return value from get_eit_entry() is now returned without
  translating it to _URC_FAILURE, so that callers can see _URC_END_OF_STACK
  when it happens.

Modified:
  stable/11/contrib/gcc/config/arm/unwind-arm.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/contrib/gcc/config/arm/unwind-arm.c
==============================================================================
--- stable/11/contrib/gcc/config/arm/unwind-arm.c	Thu Oct 19 16:42:03 2017	(r324759)
+++ stable/11/contrib/gcc/config/arm/unwind-arm.c	Thu Oct 19 17:26:26 2017	(r324760)
@@ -625,8 +625,8 @@ __gnu_Unwind_RaiseException (_Unwind_Control_Block * u
   do
     {
       /* Find the entry for this routine.  */
-      if (get_eit_entry (ucbp, saved_vrs.core.r[R_PC]) != _URC_OK)
-	return _URC_FAILURE;
+      if ((pr_result = get_eit_entry (ucbp, saved_vrs.core.r[R_PC])) != _URC_OK)
+	return pr_result;
 
       /* Call the pr to decide what to do.  */
       pr_result = ((personality_routine) UCB_PR_ADDR (ucbp))
@@ -773,11 +773,8 @@ __gnu_Unwind_Backtrace(_Unwind_Trace_Fn trace, void * 
   do
     {
       /* Find the entry for this routine.  */
-      if (get_eit_entry (ucbp, saved_vrs.core.r[R_PC]) != _URC_OK)
-	{
-	  code = _URC_FAILURE;
+      if ((code = get_eit_entry (ucbp, saved_vrs.core.r[R_PC])) != _URC_OK)
 	  break;
-	}
 
       /* The dwarf unwinder assumes the context structure holds things
 	 like the function and LSDA pointers.  The ARM implementation