commit f193878a242f5b86db62986a9b2cba5d99505c17
author Christopher Ferris <cferris@google.com> Wed Mar 09 16:03:00 2016 -0800
committer Christopher Ferris <cferris@google.com> Thu Mar 10 11:33:39 2016 -0800
tree 006fa6ec8d30c4d43bf9120964527ff087ef3292
parent 2048b01dfec8877d672a4da41a158f68b12b5337

Log when why an Unwind failed.

Bug: 27449879
Change-Id: If7ae5f0991da6fd64dd45e22d69eecef1388a28e

runtime/utils.cc

diff --git a/runtime/utils.cc b/runtime/utils.cc
index 13564a6..472a85c 100644
--- a/runtime/utils.cc
+++ b/runtime/utils.cc
@@ -1120,7 +1120,8 @@
   }
   std::unique_ptr<Backtrace> backtrace(Backtrace::Create(BACKTRACE_CURRENT_PROCESS, tid, map));
   if (!backtrace->Unwind(0, reinterpret_cast<ucontext*>(ucontext_ptr))) {
-    os << prefix << "(backtrace::Unwind failed for thread " << tid << ")\n";
+    os << prefix << "(backtrace::Unwind failed for thread " << tid
+       << ": " <<  backtrace->GetErrorString(backtrace->GetError()) << ")\n";
     return;
   } else if (backtrace->NumFrames() == 0) {
     os << prefix << "(no native stack frames for thread " << tid << ")\n";