Discards frames for code within library.

When doing a local unwind, do not include the frames that come
from either libunwind or libbacktrace.

Bug: 11518609
Change-Id: I0ec8d823aebbfa0903e61b16b7e5663f3fd65e78

1 files changed, 18 insertions, 0 deletions

diff --git a/libbacktrace/backtrace_test.cpp b/libbacktrace/backtrace_test.cpp
index d408856..5de80b1 100644
--- a/libbacktrace/backtrace_test.cpp
+++ b/libbacktrace/backtrace_test.cpp
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#define _GNU_SOURCE 1
 #include <dirent.h>
 #include <errno.h>
 #include <inttypes.h>
@@ -200,6 +201,23 @@ bool WaitForNonZero(int32_t* value, uint64_t seconds) {
   return false;
 }
 
+TEST(libbacktrace, local_no_unwind_frames) {
+  // Verify that a local unwind does not include any frames within
+  // libunwind or libbacktrace.
+  std::unique_ptr<Backtrace> backtrace(Backtrace::Create(getpid(), getpid()));
+  ASSERT_TRUE(backtrace->Unwind(0));
+
+  ASSERT_TRUE(backtrace->NumFrames() != 0);
+  for (const auto& frame : *backtrace ) {
+    if (BacktraceMap::IsValid(frame.map)) {
+      const std::string name = basename(frame.map.name.c_str());
+      ASSERT_TRUE(name != "libunwind.so" && name != "libbacktrace.so")
+        << DumpFrames(backtrace.get());
+    }
+    break;
+  }
+}
+
 TEST(libbacktrace, local_trace) {
   ASSERT_NE(test_level_one(1, 2, 3, 4, VerifyLevelBacktrace, nullptr), 0);
 }