[cmake] Update lit search to match the one in LLVM

[mgorny]

Summary

Update the lit search logic to support all names supported in LLVM (since r283029). The search order (i.e. PATHS vs HINTS) does no really matter since the established path is not used, except for determining whether lit is available.

[mgorny]

Let's wait for the reply on D23743.

[mgorny]

A gentle ping here.

[beanz]

Is there a bug you're trying to fix here? It seems to me that the existing behavior works correctly. I'm also pretty sure from the comment in D23743 that llvm-lit shouldn't be in the list.

[mgorny]

In D23745#572517, @beanz wrote:

Is there a bug you're trying to fix here? It seems to me that the existing behavior works correctly. I'm also pretty sure from the comment in D23743 that llvm-lit shouldn't be in the list.

I'm trying to sync clang to core llvm, so that the lit search results match. For example, on my system clang would not be able to find lit and it would assume that it isn't installed while llvm (and therefore add_lit_testsuite) would find lit just fine.

[beanz]

Gotcha. LGTM!

cfe/trunk/CMakeLists.txt

Please install Python or specify the PYTHON_EXECUTABLE CMake variable.")
     # Check prebuilt llvm/utils.
     if(EXISTS ${LLVM_TOOLS_BINARY_DIR}/FileCheck${CMAKE_EXECUTABLE_SUFFIX}
         AND EXISTS ${LLVM_TOOLS_BINARY_DIR}/count${CMAKE_EXECUTABLE_SUFFIX}
         AND EXISTS ${LLVM_TOOLS_BINARY_DIR}/not${CMAKE_EXECUTABLE_SUFFIX})
       set(LLVM_UTILS_PROVIDED ON)
     endif()
 
     if(EXISTS ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
+      # Note: path not really used, except for checking if lit was found
       set(LLVM_LIT ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
       if(NOT LLVM_UTILS_PROVIDED)
         add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/FileCheck utils/FileCheck)
         add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/count utils/count)
         add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/not utils/not)
         set(LLVM_UTILS_PROVIDED ON)
         set(CLANG_TEST_DEPS FileCheck count not)
       endif()
       set(UNITTEST_DIR ${LLVM_MAIN_SRC_DIR}/utils/unittest)
       if(EXISTS ${UNITTEST_DIR}/googletest/include/gtest/gtest.h
           AND NOT EXISTS ${LLVM_LIBRARY_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}gtest${CMAKE_STATIC_LIBRARY_SUFFIX}
           AND EXISTS ${UNITTEST_DIR}/CMakeLists.txt)
         add_subdirectory(${UNITTEST_DIR} utils/unittest)
       endif()
     else()
       # Seek installed Lit.
-      find_program(LLVM_LIT "lit.py" ${LLVM_MAIN_SRC_DIR}/utils/lit
+      find_program(LLVM_LIT
+                   NAMES llvm-lit lit.py lit
+                   PATHS "${LLVM_MAIN_SRC_DIR}/utils/lit"
                    DOC "Path to lit.py")
     endif()
 
     if(LLVM_LIT)
       # Define the default arguments to use with 'lit', and an option for the user
       # to override.
       set(LIT_ARGS_DEFAULT "-sv")
       if (MSVC OR XCODE)
         set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")