[PATCH v3 2/3] stack: check frame_unwind_caller_id

[Markus Metzger <markus.t.metzger@intel.com>]

Callers of frame_unwind_caller_* functions are supposed to check
frame_unwind_caller_id.

Add such a check to frame_info and treat an invalid caller ID as if the caller
PC were not available.

2016-02-11  Markus Metzger  <markus.t.metzger@intel.com>

gdb/
	* stack.c (frame_info): Check frame_unwind_caller_id.
---
 gdb/stack.c | 39 ++++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 17 deletions(-)

diff --git a/gdb/stack.c b/gdb/stack.c
index 89879f3..6e3acc7 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -1509,27 +1509,32 @@ frame_info (char *addr_exp, int from_tty)
   wrap_here ("    ");
   printf_filtered ("saved %s = ", pc_regname);
 
-  TRY
-    {
-      caller_pc = frame_unwind_caller_pc (fi);
-      caller_pc_p = 1;
-    }
-  CATCH (ex, RETURN_MASK_ERROR)
+  if (!frame_id_p (frame_unwind_caller_id (fi)))
+    val_print_unavailable (gdb_stdout);
+  else
     {
-      switch (ex.error)
+      TRY
 	{
-	case NOT_AVAILABLE_ERROR:
-	  val_print_unavailable (gdb_stdout);
-	  break;
-	case OPTIMIZED_OUT_ERROR:
-	  val_print_not_saved (gdb_stdout);
-	  break;
-	default:
-	  fprintf_filtered (gdb_stdout, _("<error: %s>"), ex.message);
-	  break;
+	  caller_pc = frame_unwind_caller_pc (fi);
+	  caller_pc_p = 1;
 	}
+      CATCH (ex, RETURN_MASK_ERROR)
+	{
+	  switch (ex.error)
+	    {
+	    case NOT_AVAILABLE_ERROR:
+	      val_print_unavailable (gdb_stdout);
+	      break;
+	    case OPTIMIZED_OUT_ERROR:
+	      val_print_not_saved (gdb_stdout);
+	      break;
+	    default:
+	      fprintf_filtered (gdb_stdout, _("<error: %s>"), ex.message);
+	      break;
+	    }
+	}
+      END_CATCH
     }
-  END_CATCH
 
   if (caller_pc_p)
     fputs_filtered (paddress (gdbarch, caller_pc), gdb_stdout);
-- 
1.8.3.1