[Lldb-commits] [PATCH] D125042: have crashlog.py insert a stack frame with $lr when stack frame 0 is address 0

[Jason Molenda via Phabricator via lldb-commits]

jasonmolenda updated this revision to Diff 427501.
jasonmolenda added a comment.

update to incorporate dave's suggestions.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D125042/new/

https://reviews.llvm.org/D125042

Files:
  lldb/examples/python/crashlog.py


Index: lldb/examples/python/crashlog.py
===================================================================
--- lldb/examples/python/crashlog.py
+++ lldb/examples/python/crashlog.py
@@ -516,6 +516,23 @@
             image_addr = self.get_used_image(image_id)['base']
             pc = image_addr + frame_offset
             thread.frames.append(self.crashlog.Frame(idx, pc, frame_offset))
+
+            # on arm64 systems, if it jump through a null function pointer,
+            # we end up at address 0 and the crash reporter unwinder 
+            # misses the frame that actually faulted.  
+            # But $lr can tell us where the last BL/BLR instruction used 
+            # was at, so insert that address as the caller stack frame.  
+            if idx == 0 and pc == 0 and "lr" in thread.registers:
+                pc = thread.registers["lr"]
+                for image in self.data['usedImages']:
+                    text_lo = image['base']
+                    text_hi = text_lo + image['size']
+                    if text_lo <= pc < text_hi:
+                      idx += 1
+                      frame_offset = pc - text_lo
+                      thread.frames.append(self.crashlog.Frame(idx, pc, frame_offset))
+                      break
+
             idx += 1
 
     def parse_threads(self, json_threads):
@@ -551,7 +568,7 @@
                 continue
             try:
                 value = int(state['value'])
-                registers["{}{}".format(prefix,key)] = value
+                registers["{}{}".format(prefix or '',key)] = value
             except (KeyError, ValueError, TypeError):
                 pass
         return registers


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