[Lldb-commits] [PATCH] D126464: [lldb] Add support to load object files from thin archives

Greg Clayton via Phabricator via lldb-commits lldb-commits at lists.llvm.org
Tue May 31 09:05:51 PDT 2022

clayborg added a comment.

In D126464#3545142 <https://reviews.llvm.org/D126464#3545142>, @PRESIDENT810 wrote:

> I have refactored my code so it should looks cleaner now, but I'm not sure how to add a test. It seems that adding a test for thin archive on macOS platforms can be not so straightforward. I see that in lldb/test/API/functionalities/archives/Makefile, the test suite is using libtool instead of ar to create archives on macOS platforms, and I don't know whether I can produce a thin archive with that. Also, ld on macOS platforms seems to be unable to identify thin archives (I'm using ld64.lld when testing my code locally).
> I would really appreciate it if someone can provide some advice about how to implement such a test case here, thank you!

Does LLVM have the ability to generate a "llvm-ar" tool that can do the packaging? If so, an easy test would be to create a thin archive and then run the following API from within python:

  static SBModuleSpecList SBModuleSpecList::GetModuleSpecifications(const char *path);

If you run this API on a thin archive without your modifications, then you will probably get an empty SBModuleSpecList object. So the flow would be:

- make sure "llvm-ar" is built if it already isn't with the "check-lldb" target (might need to add it as a depedency
- use the build "llvm-ar" to make an archive that points to two .o files that you build from sources
- then run some python in your test case like:

  # Make the Makefile that uses the built "llvm-ar"  one two source files that have .o created for them, and then it runs "llvm-ar" and will produce the "thin.a" in the output directory
  # This line will point to the "thin.a" that was just built
  archive_path = self.getBuildArtifact("thin.a")
  # Get the module specs from the thin archive
  module_specs = lldb.SBModuleSpecList.GetModuleSpecifications(archive_path)
  num_specs = module_specs.GetSize()
  self.assertEqual(num_specs, 2)
  # For extra credit you can verify that you get the right file path from each file spec
  obj_path_1 = self.getBuildArtifact("foo.o")
  obj_path_2 = self.getBuildArtifact("bar.o")
  self.assertEqual(module_specs.GetSpecAtIndex(0).GetObjectName(), obj_path_1)
  self.assertEqual(module_specs.GetSpecAtIndex(1).GetObjectName(), obj_path_2)



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