2 files changed, 8 insertions, 2 deletions

diff --git a/include/backtrace/Backtrace.h b/include/backtrace/Backtrace.h
index c896ab806..4f73a658c 100644
--- a/include/backtrace/Backtrace.h
+++ b/include/backtrace/Backtrace.h
@@ -104,8 +104,10 @@ public:
   virtual bool Unwind(size_t num_ignore_frames, ucontext_t* context = NULL) = 0;
 
   // Get the function name and offset into the function given the pc.
-  // If the string is empty, then no valid function name was found.
-  virtual std::string GetFunctionName(uintptr_t pc, uintptr_t* offset);
+  // If the string is empty, then no valid function name was found,
+  // or the pc is not in any valid map.
+  virtual std::string GetFunctionName(uintptr_t pc, uintptr_t* offset,
+                                      const backtrace_map_t* map = NULL);
 
   // Fill in the map data associated with the given pc.
   virtual void FillInMap(uintptr_t pc, backtrace_map_t* map);
diff --git a/include/backtrace/BacktraceMap.h b/include/backtrace/BacktraceMap.h
index df48dfe2b..8ab0dfabb 100644
--- a/include/backtrace/BacktraceMap.h
+++ b/include/backtrace/BacktraceMap.h
@@ -33,6 +33,10 @@
 #include <string>
 #include <vector>
 
+// Special flag to indicate a map is in /dev/. However, a map in
+// /dev/ashmem/... does not set this flag.
+static constexpr int PROT_DEVICE_MAP = 0x8000;
+
 struct backtrace_map_t {
   uintptr_t start = 0;
   uintptr_t end = 0;