[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/8cc1abaa499e
branches:  trunk
changeset: 320759:8cc1abaa499e
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 7764c30dfb27 -r 8cc1abaa499e 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 7764c30dfb27 -r 8cc1abaa499e 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) {