[lldb/crashlog] Fix line entries resolution in interactive mode

[mib]

Summary

This patch subtracts 1 to the pc of any frame above frame 0 to get the
previous line entry and display the right line in the debugger.

This also rephrase some old comment from 48d157dd4.

rdar://92686666

Signed-off-by: Med Ismail Bennani <[e-mail]>

[JDevlieghere]

lldb/examples/python/crashlog.py

118–119

Maybe

Except for the zeroth frame, we should subtract 1 from every frame pc in order to get to the previous line entry

[mib]

Updated comment

[JDevlieghere]

LGTM

lldb/examples/python/crashlog.py

class Thread:
                     return
 
             print("%s" % self)
             display_frame_idx = -1
             for frame_idx, frame in enumerate(self.frames):
                 disassemble = (
                     this_thread_crashed or options.disassemble_all_threads) and frame_idx < options.disassemble_depth
 
-                # Any frame above frame zero and we have to subtract one to
-                # get the previous line entry.
+                # We should substract 1 to every frame's pc above frame zero
+                # 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
                     for symbolicated_frame_address in symbolicated_frame_addresses:
                         display_frame_idx += 1

lldb/examples/python/scripted_process/crashlog_scripted_process.py

 class CrashLogScriptedProcess(ScriptedProcess):
     def parse_crashlog(self):
         try:
             crash_log = CrashLogParser().parse(self.dbg, self.crashlog_path, False)
         except Exception as e:
             return
 
         self.pid = crash_log.process_id
+        self.addr_mask = crash_log.addr_mask
         self.crashed_thread_idx = crash_log.crashed_thread_idx
         self.loaded_images = []
 
         def load_images(self, images):
             #TODO: Add to self.loaded_images and load images in lldb
             if images:
                 for image in images:
                     if image not in self.loaded_images:
class CrashLogScriptedThread(ScriptedThread):
     def create_stackframes(self):
         if not (self.scripted_process.load_all_images or self.has_crashed):
             return None
 
         if not self.backing_thread or not len(self.backing_thread.frames):
             return None
 
         for frame in self.backing_thread.frames:
+            frame_pc = frame.pc & self.scripted_process.addr_mask
+            pc = frame_pc if frame.index == 0  or frame_pc == 0 else frame_pc - 1
             sym_addr = lldb.SBAddress()
-            sym_addr.SetLoadAddress(frame.pc, self.target)
+            sym_addr.SetLoadAddress(pc, self.target)
             if not sym_addr.IsValid():
                 continue
-            self.frames.append({"idx": frame.index, "pc": frame.pc})
+            self.frames.append({"idx": frame.index, "pc": pc})
 
         return self.frames
 
     def __init__(self, process, args, crashlog_thread):
         super().__init__(process, args)
 
         self.backing_thread = crashlog_thread
         self.idx = self.backing_thread.index