[Lldb-commits] [PATCH] D125716: [lldb] Prevent Overflow (Underflow) error in crashlog.py

[Jonas Devlieghere via Phabricator via lldb-commits]

JDevlieghere created this revision.
JDevlieghere added a reviewer: mib.
Herald added a project: All.
JDevlieghere requested review of this revision.

Avoid a OverflowError when the pc is zero. This can happen for "unknown frames" 
where the crashlog generator reports a zero pc. We could omit them altogether, 
but if they're part of the crashlog it seems fair to display them in lldb as 
well.

rdar://92686666


https://reviews.llvm.org/D125716

Files:
  lldb/examples/python/crashlog.py


Index: lldb/examples/python/crashlog.py
===================================================================
--- lldb/examples/python/crashlog.py
+++ lldb/examples/python/crashlog.py
@@ -114,14 +114,12 @@
             for frame_idx, frame in enumerate(self.frames):
                 disassemble = (
                     this_thread_crashed or options.disassemble_all_threads) 
and frame_idx < options.disassemble_depth
-                if frame_idx == 0:
-                    symbolicated_frame_addresses = crash_log.symbolicate(
-                        frame.pc & crash_log.addr_mask, options.verbose)
-                else:
-                    # Any frame above frame zero and we have to subtract one to
-                    # get the previous line entry
-                    symbolicated_frame_addresses = crash_log.symbolicate(
-                        (frame.pc & crash_log.addr_mask) - 1, options.verbose)
+
+                # Any frame above frame zero and we have to subtract one to
+                # get the previous line entry.
+                pc = frame.pc & crash_log.addr_mask
+                pc = pc if frame_idx == 0 or pc == 0 else pc - 1
+                symbolicated_frame_addresses = crash_log.symbolicate(pc, 
options.verbose)
 
                 if symbolicated_frame_addresses:
                     symbolicated_frame_address_idx = 0



Index: lldb/examples/python/crashlog.py
===================================================================
--- lldb/examples/python/crashlog.py
+++ lldb/examples/python/crashlog.py
@@ -114,14 +114,12 @@
             for frame_idx, frame in enumerate(self.frames):
                 disassemble = (
                     this_thread_crashed or options.disassemble_all_threads) and frame_idx < options.disassemble_depth
-                if frame_idx == 0:
-                    symbolicated_frame_addresses = crash_log.symbolicate(
-                        frame.pc & crash_log.addr_mask, options.verbose)
-                else:
-                    # Any frame above frame zero and we have to subtract one to
-                    # get the previous line entry
-                    symbolicated_frame_addresses = crash_log.symbolicate(
-                        (frame.pc & crash_log.addr_mask) - 1, options.verbose)
+
+                # Any frame above frame zero and we have to subtract one to
+                # get the previous line entry.
+                pc = frame.pc & crash_log.addr_mask
+                pc = pc if frame_idx == 0 or pc == 0 else pc - 1
+                symbolicated_frame_addresses = crash_log.symbolicate(pc, options.verbose)
 
                 if symbolicated_frame_addresses:
                     symbolicated_frame_address_idx = 0

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