[Lldb-commits] [PATCH] D126260: [lldb/crashlog] Add support for Application Specific Backtraces

[Med Ismail Bennani via Phabricator via lldb-commits]

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For an exception crashlog, the thread backtracesaren't usually very helpful
and instead, developpers look at the "Application Specific Backtrace" that
was generated by `objc_exception_throw`.

LLDB could already parse and symbolicate these Application Specific Backtraces
for regular textual-based crashlog, so this patch adds support to parse them
in JSON crashlogs.

Signed-off-by: Med Ismail Bennani <medismail.bennani at gmail.com>


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D126260

Files:
  lldb/examples/python/crashlog.py
  lldb/examples/python/scripted_process/crashlog_scripted_process.py


Index: lldb/examples/python/scripted_process/crashlog_scripted_process.py
===================================================================
--- lldb/examples/python/scripted_process/crashlog_scripted_process.py
+++ lldb/examples/python/scripted_process/crashlog_scripted_process.py
@@ -140,6 +140,8 @@
         self.idx = self.backing_thread.index
         self.tid = self.backing_thread.id
         self.name = self.backing_thread.name
+        if self.backing_thread.app_specific_backtrace:
+            self.name = "Application Specific Backtrace - " + str(self.idx)
         self.queue = self.backing_thread.queue
         self.has_crashed = (self.scripted_process.crashed_thread_idx == self.idx)
         self.create_stackframes()
Index: lldb/examples/python/crashlog.py
===================================================================
--- lldb/examples/python/crashlog.py
+++ lldb/examples/python/crashlog.py
@@ -449,6 +449,8 @@
             self.parse_images(self.data['usedImages'])
             self.parse_main_image(self.data)
             self.parse_threads(self.data['threads'])
+            if 'asiBacktraces' in self.data:
+                self.parse_app_specific_backtraces(self.data['asiBacktraces'])
             self.parse_errors(self.data)
             thread = self.crashlog.threads[self.crashlog.crashed_thread_idx]
             reason = self.parse_crash_reason(self.data['exception'])
@@ -560,6 +562,37 @@
             self.crashlog.threads.append(thread)
             idx += 1
 
+    def parse_app_specific_backtraces(self, json_app_specific_bts):
+        def parse_asi_backtrace(self, thread, bt):
+            frame_regex = re.compile(r'^([0-9]+)' r'\s'                # id
+                            r'+(.+?)'    r'\s+'               # img_name
+                            r'(0x[0-9a-fA-F]{7}[0-9a-fA-F]+)' # addr
+                            r' +(.*)'                         # offs
+                        )
+
+            for line in bt.split('\n'):
+                frame_match = frame_regex.search(line)
+                if not frame_match:
+                    print("error: Couldn't parse Application Specific Backtrace.")
+                    return False
+
+                (frame_id, frame_img_name,
+                    frame_addr, frame_ofs) = frame_match.groups()
+
+                thread.add_ident(frame_img_name)
+                if frame_img_name not in self.crashlog.idents:
+                    self.crashlog.idents.append(frame_img_name)
+                thread.frames.append(self.crashlog.Frame(int(frame_id), int(
+                    frame_addr, 0), frame_ofs))
+
+            return True
+
+        for idx, backtrace in enumerate(json_app_specific_bts):
+            thread = self.crashlog.Thread(idx, True)
+            thread.queue = "Application Specific Backtraces"
+            if parse_asi_backtrace(self, thread, backtrace):
+                self.crashlog.threads.append(thread)
+
     def parse_thread_registers(self, json_thread_state, prefix=None):
         registers = dict()
         for key, state in json_thread_state.items():


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