commit 785414705628bf9d1279a8042e1886440424aade
author Cherry Zhang <cherryyz@google.com> Mon Dec 24 16:08:05 2018 -0500
committer Ian Lance Taylor <iant@golang.org> Thu Dec 27 03:12:31 2018 +0000
tree fcf8924de8c5c8514d6f5f2008f2c7a48c1fc399
parent 16a48dbc1c69075321b388d235651b59abcb58ce

runtime: on ARM32 EABI, don't get LSDA if compact model is used

On ARM32 EABI, when the "compact" unwinding model is used, it
does not have standard LSDA and _Unwind_GetLanguageSpecificData
will not return data that is parseable by us. Check this
conditon before calling _Unwind_GetLanguageSpecificData.

Fix ARM32 build.

Change-Id: I24dfbdd61530ebf3ecae83b1764f751d676f4b20
Reviewed-on: https://go-review.googlesource.com/c/155758
Reviewed-by: Ian Lance Taylor <iant@golang.org>

libgo/runtime/go-unwind.c

diff --git a/libgo/runtime/go-unwind.c b/libgo/runtime/go-unwind.c
index f4bbfb6..388d7c7 100644
--- a/libgo/runtime/go-unwind.c
+++ b/libgo/runtime/go-unwind.c
@@ -646,6 +646,17 @@
   _sleb128_t index;
   int size;
 
+#ifdef __ARM_EABI_UNWINDER__
+  {
+    _Unwind_Control_Block *ucbp;
+    ucbp = (_Unwind_Control_Block *) _Unwind_GetGR (context, 12);
+    if (*ucbp->pr_cache.ehtp & (1u << 31))
+      // The "compact" model is used, with one of the predefined
+      // personality functions. It doesn't have standard LSDA.
+      return NOTFOUND_OK;
+  }
+#endif
+
   language_specific_data = (const unsigned char *)
     _Unwind_GetLanguageSpecificData (context);