[lldb/crashlog] Add '-t|--target' option to interactive mode

[mib]

Summary

This patch introduces a new flag for the interactive crashlog mode, that
allow the user to specify, which target to use to create the scripted
process.

This can be very useful when lldb already have few targets created:
Instead of taking the first one (zeroth index), we will use that flag to
create a new target. If the user didn't provide a target path, we will rely
on the symbolicator to create a targer.If that fails and there are already
some targets loaded in lldb, we use the first one.

rdar://94682869

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

[JDevlieghere]

lldb/examples/python/crashlog.py

1022

1024

I think if the user provided a target path and that didn't work, we should report and error and give up.

1025

1200

Please make it clear that this is optional and describe the fallback behavior.

lldb/examples/python/scripted_process/crashlog_scripted_process.py

46–47

Maybe leave a comment why the executable matters here rather than just the target.

47–48

The comment says return error but we're not returning anything. Should this raise an exception?

[mib]

lldb/examples/python/scripted_process/crashlog_scripted_process.py

47–48

I was thinking of adding a SBCommandObjectReturn to every script process init function so we print errors in lldb instead of raising a python exception. That way we could propage that into the IDEs.
I'm doing that in a follow-up patch.

[mib]

Address @JDevlieghere feedbacks.

[mib]

Make lit run command more readable

[JDevlieghere]

lldb/examples/python/crashlog.py

1025

This is not an f-string so this will actually print {option.target_path} rather than the actual value. That said, we don't use those anywhere else, so let's use .format() to be consistent.

lldb/test/Shell/ScriptInterpreter/Python/Crashlog/scripted_crashlog_json.test

5

Can we test some of the error cases here? Should be easy enough to provide a target that doesn't exist (and would've caught the f-string issue).

[mib]

lldb/examples/python/crashlog.py

1025

.format() was too long compared to using an f-string :p that why I went with that ... I'll update it

lldb/test/Shell/ScriptInterpreter/Python/Crashlog/scripted_crashlog_json.test

5

I tried having a first crashlog command with an invalid target fail before the one that works but lit would just stop at the error. Instead, I test it in D129614.

[mib]

Change f-string to string.format

[JDevlieghere]

LGTM modulo the # Return error but that's addressed in a follow up patch.

lldb/examples/python/crashlog.py

def load_crashlog_in_scripted_process(debugger, crash_log_file, options):
     result = lldb.SBCommandReturnObject()
 
     crashlog_path = os.path.expanduser(crash_log_file)
     if not os.path.exists(crashlog_path):
         result.PutCString("error: crashlog file %s does not exist" % crashlog_path)
 
     crashlog = CrashLogParser().parse(debugger, crashlog_path, False)
 
-    if debugger.GetNumTargets() > 0:
-        target = debugger.GetTargetAtIndex(0)
-    else:
-        target = crashlog.create_target()
+    target = lldb.SBTarget()
+    # 1. Try to use the user-provided target
+    if options.target_path:
+        target = debugger.CreateTarget(options.target_path)
         if not target:
+            result.PutCString("error: couldn't create target provided by the user ({option.target_path})")
+            return
+    # 2. If the user didn't provide a target, try to create a target using the symbolicator
+    if not target or not target.IsValid():
+        target = crashlog.create_target()
+    # 3. If that didn't work, and a target is already loaded, use it
+    if (target is None  or not target.IsValid()) and debugger.GetNumTargets() > 0:
+        target = debugger.GetTargetAtIndex(0)
+    # 4. Fail
+    if target is None or not target.IsValid():
         result.PutCString("error: couldn't create target")
         return
 
     ci = debugger.GetCommandInterpreter()
     if not ci:
         result.PutCString("error: couldn't get command interpreter")
         return
 
if add_interactive_options:
             help='parse a crash log and load it in a ScriptedProcess',
             default=False)
         option_parser.add_option(
             '-b',
             '--batch',
             action='store_true',
             help='dump symbolicated stackframes without creating a debug session',
             default=True)
+        option_parser.add_option(
+            '--target',
+            '-t',
+            dest='target_path',
+            help='the target binary path that should be used for interactive crashlog (optional)',
+            default=None)
     return option_parser
 
 
 def CrashLogOptionParser():
     description = '''Symbolicate one or more darwin crash log files to provide source file and line information,
 inlined stack frames back to the concrete functions, and disassemble the location of the crash
 for the first frame of the crashed thread.
 If this script is imported into the LLDB command interpreter, a "crashlog" command will be added to the interpreter

lldb/examples/python/scripted_process/crashlog_scripted_process.py

 import os,json,struct,signal
 
 from typing import Any, Dict
 
 import lldb
 from lldb.plugins.scripted_process import ScriptedProcess
 from lldb.plugins.scripted_process import ScriptedThread
 
 from lldb.macosx.crashlog import CrashLog,CrashLogParser
 
 class CrashLogScriptedProcess(ScriptedProcess):
     def parse_crashlog(self):
         try:
             crash_log = CrashLogParser().parse(self.dbg, self.crashlog_path, False)
         except Exception as e:
-            return
+            raise e
 
         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
def parse_crashlog(self):
                 for ident in thread.idents:
                     load_images(self, crash_log.find_images_with_identifier(ident))
 
             self.threads[thread.index] = CrashLogScriptedThread(self, None, thread)
 
     def __init__(self, target: lldb.SBTarget, args : lldb.SBStructuredData):
         super().__init__(target, args)
 
         if not self.target or not self.target.IsValid():
+            # Return error
             return
 
         self.crashlog_path = None
 
         crashlog_path = args.GetValueForKey("crashlog_path")
         if crashlog_path and crashlog_path.IsValid():
             if crashlog_path.GetType() == lldb.eStructuredDataTypeString:
                 self.crashlog_path = crashlog_path.GetStringValue(4096)
 
         if not self.crashlog_path:
+            # Return error
             return
 
         load_all_images = args.GetValueForKey("load_all_images")
         if load_all_images and load_all_images.IsValid():
             if load_all_images.GetType() == lldb.eStructuredDataTypeBoolean:
                 self.load_all_images = load_all_images.GetBooleanValue()
 
         if not self.load_all_images:

lldb/test/Shell/ScriptInterpreter/Python/Crashlog/scripted_crashlog_json.test

 # REQUIRES: python, native && target-aarch64 && system-darwin
 
 # RUN: mkdir -p %t.dir
 # RUN: yaml2obj %S/Inputs/interactive_crashlog/multithread-test.yaml > %t.dir/multithread-test
-# RUN: %lldb %t.dir/multithread-test -o 'command script import lldb.macosx.crashlog' -o 'crashlog -a -i %S/Inputs/interactive_crashlog/multithread-test.ips' -o "thread list" -o "bt all" 2>&1 | FileCheck %s
+# RUN: %lldb -o 'command script import lldb.macosx.crashlog' -o 'crashlog -a -i -t %t.dir/multithread-test %S/Inputs/interactive_crashlog/multithread-test.ips' -o "thread list" -o "bt all" 2>&1 | FileCheck %s
 
 # CHECK: "crashlog" {{.*}} commands have been installed, use the "--help" options on these commands
 
 # CHECK: (lldb) process status
 # CHECK-NEXT: Process 22511 stopped
 # CHECK-NEXT: * thread #3, stop reason = EXC_BAD_ACCESS
 # CHECK-NEXT:     frame #0: 0x0000000100ec58f4 multithread-test`bar