> Is the use of llvm-lto and opt here just to do testing before the clang and lld patches go in? If so, do we need cross project testing right now? Wondering if it would be better to just stick with the testing you have in this patch that is under llvm/test, and add the cross project testing using only external tools once those patches are in.

This test checks that the DTLTO code that the code that creates Clang command lines generates the expected options and that those options are accepted by clang. I wrote it to use llvm-lto and opt so it could be part of this commit before the clang and lld patches go in. However, I think it is a nice principle to only use external tools in cross-project-tests. I have removed the test from this PR with the intention of adding it back later. Additionally if we can use your idea (llvm#127749 (comment)) of storing the Clang `-c` step options and applying them to the remote backend compilations then this test will be rewritten to test that behaviour instead.

Author: bd1976bris

cross-project-tests/CMakeLists.txt

@@ -19,13 +19,11 @@ set(CROSS_PROJECT_TEST_DEPS
   FileCheck
   check-gdb-llvm-support
   count
-  llvm-config
   llvm-dwarfdump
-  llvm-lto2
+  llvm-config
   llvm-objdump
-  not
-  opt
   split-file
+  not
   )
 
 if ("clang" IN_LIST LLVM_ENABLE_PROJECTS)
@@ -96,13 +94,6 @@ add_lit_testsuite(check-cross-amdgpu "Running AMDGPU cross-project tests"
   DEPENDS clang
   )
 
-# DTLTO tests.
-add_lit_testsuite(check-cross-dtlto "Running DTLTO cross-project tests"
-  ${CMAKE_CURRENT_BINARY_DIR}/dtlto
-  EXCLUDE_FROM_CHECK_ALL
-  DEPENDS ${CROSS_PROJECT_TEST_DEPS}
-  )
-
 # Add check-cross-project-* targets.
 add_lit_testsuites(CROSS_PROJECT ${CMAKE_CURRENT_SOURCE_DIR}
   DEPENDS ${CROSS_PROJECT_TEST_DEPS}

cross-project-tests/dtlto/README.md

@@ -19,7 +19,7 @@
 config.test_format = lit.formats.ShTest(not llvm_config.use_lit_shell)
 
 # suffixes: A list of file extensions to treat as test files.
-config.suffixes = [".c", ".cl", ".cpp", ".m", ".ll"]
+config.suffixes = [".c", ".cl", ".cpp", ".m"]
 
 # excludes: A list of directories to exclude from the testsuite. The 'Inputs'
 # subdirectories contain auxiliary inputs for various tests in their parent
@@ -96,9 +96,6 @@ def get_required_attr(config, attr_name):
 if lldb_path is not None:
     config.available_features.add("lldb")
 
-for tool in ["llvm-lto2", "opt"]:
-    if llvm_config.use_llvm_tool(tool):
-        config.available_features.add(tool)
 
 def configure_dexter_substitutions():
     """Configure substitutions for host platform and return list of dependencies"""