[src/trunk]: src/sys/lib/libunwind The semantics of DW_CFA_GNU_args_size have...

[joerg <joerg%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/a7497954e864
branches:  trunk
changeset: 833946:a7497954e864
user:      joerg <joerg%NetBSD.org@localhost>
date:      Tue Jul 17 19:01:16 2018 +0000

description:
The semantics of DW_CFA_GNU_args_size have changed subtile over the
years. Adopt the new convention that it is call-site specific and that
it should be applied before moving the IP by personality routines, but
not during normal unwinding. Further discussion can be found in
LLVM's phabricator review D38680.

diffstat:

 sys/lib/libunwind/UnwindCursor.hpp |  3 ---
 sys/lib/libunwind/libunwind.cxx    |  2 ++
 2 files changed, 2 insertions(+), 3 deletions(-)

diffs (25 lines):

diff -r dfb5e0cc89b9 -r a7497954e864 sys/lib/libunwind/UnwindCursor.hpp
--- a/sys/lib/libunwind/UnwindCursor.hpp        Tue Jul 17 18:58:58 2018 +0000
+++ b/sys/lib/libunwind/UnwindCursor.hpp        Tue Jul 17 19:01:16 2018 +0000
@@ -61,9 +61,6 @@
       this->setInfoBasedOnIPRegister(true);
       if (fUnwindInfoMissing)
         return UNW_STEP_END;
-
-      if (fInfo.extra_args)
-        setSP(getSP() + fInfo.extra_args);
       return UNW_STEP_SUCCESS;
     }
     __builtin_unreachable();
diff -r dfb5e0cc89b9 -r a7497954e864 sys/lib/libunwind/libunwind.cxx
--- a/sys/lib/libunwind/libunwind.cxx   Tue Jul 17 18:58:58 2018 +0000
+++ b/sys/lib/libunwind/libunwind.cxx   Tue Jul 17 19:01:16 2018 +0000
@@ -277,6 +277,8 @@
   unw_proc_info_t info;
   cursor->getInfo(&info);
   cursor->setInfoBasedOnIPRegister(false);
+  if (info.extra_args)
+    cursor->setSP(cursor->getSP() + info.extra_args);
 }
 
 uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context *context) {