[Lldb-commits] [lldb] e31b2d7 - [lldb][crashlog] Avoid specifying arch for image when a UUID is present

[Vedant Kumar via lldb-commits]

Author: Vedant Kumar
Date: 2021-09-20T10:23:35-07:00
New Revision: e31b2d7d7be98cbbaa665b2702cd0ed2975da4cc

URL: https://github.com/llvm/llvm-project/commit/e31b2d7d7be98cbbaa665b2702cd0ed2975da4cc
DIFF: https://github.com/llvm/llvm-project/commit/e31b2d7d7be98cbbaa665b2702cd0ed2975da4cc.diff

LOG: [lldb][crashlog] Avoid specifying arch for image when a UUID is present

When adding an image to a target for crashlog purposes, avoid specifying
the architecture of the image.

This has the effect of making SBTarget::AddModule infer the ArchSpec for
the image based on the SBTarget's architecture, which LLDB puts serious
effort into calculating correctly (in TargetList::CreateTargetInternal).

The status quo is that LLDB randomly guesses the ArchSpec for a module
if its architecture is specified, via:

```
  SBTarget::AddModule -> Platform::GetAugmentedArchSpec -> Platform::IsCompatibleArchitecture ->
GetSupportedArchitectureAtIndex -> {ARM,x86}GetSupportedArchitectureAtIndex
```

... which means that the same crashlog can fail to load on an Apple
Silicon Mac (due to the random guess of arm64e-apple-macosx for the
module's ArchSpec not being compatible with the SBTarget's (correct)
ArchSpec), while loading just fine on an Intel Mac.

I'm not sure how to add a test for this (it doesn't look like there's
test coverage of this path in-tree). It seems like it would be pretty
complicated to regression test: the host LLDB would need to be built for
arm64e, we'd need a hand-crafted arm64e iOS crashlog, and we'd need a
binary with an iOS deployment target. I'm open to other / simpler
options.

rdar://82679400

Differential Revision: https://reviews.llvm.org/D110013

Added: 
    

Modified: 
    lldb/examples/python/symbolication.py

Removed: 
    


################################################################################
diff  --git a/lldb/examples/python/symbolication.py b/lldb/examples/python/symbolication.py
index 70f2ff3bb27c3..e15f7f4eaa3cf 100755
--- a/lldb/examples/python/symbolication.py
+++ b/lldb/examples/python/symbolication.py
@@ -379,7 +379,7 @@ def add_module(self, target):
                     return None
                 resolved_path = self.get_resolved_path()
                 self.module = target.AddModule(
-                    resolved_path, str(self.arch), uuid_str, self.symfile)
+                    resolved_path, None, uuid_str, self.symfile)
             if not self.module:
                 return 'error: unable to get module for (%s) "%s"' % (
                     self.arch, self.get_resolved_path())