[flang] unit test support for out-of-tree and in-tree using google tests framework

Review comments addressed.

flang/CMakeLists.txt

@@ -130,7 +130,50 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   option(FLANG_INCLUDE_TESTS
          "Generate build targets for the Flang unit tests."
          ON)
-  add_custom_target(check-all DEPENDS check-flang)
+
+#Handle unittests when out-of-tree
+#LLVM_BUILD_MAIN_SRC_DIR - Path to llvm source when out-of-tree.
+  set(FLANG_GTEST_AVAIL 0)
+  if (FLANG_INCLUDE_TESTS)
+    set(UNITTEST_DIR ${LLVM_BUILD_MAIN_SRC_DIR}/utils/unittest)
+    if(EXISTS ${UNITTEST_DIR}/googletest/include/gtest/gtest.h)
+      if (TARGET gtest)
+        # LLVM Doesn't export gtest's include directorys, so do that here
+        set_target_properties(gtest
+          PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
+          "${UNITTEST_DIR}/googletest/include;${UNITTEST_DIR}/googlemock/include"
+          )
+      else()
+        add_library(gtest
+          ${UNITTEST_DIR}/googletest/src/gtest-all.cc
+          ${UNITTEST_DIR}/googlemock/src/gmock-all.cc
+          )
+        target_include_directories(gtest
+          PUBLIC
+          "${UNITTEST_DIR}/googletest/include"
+          "${UNITTEST_DIR}/googlemock/include"
+
+          PRIVATE
+          "${UNITTEST_DIR}/googletest"
+          "${UNITTEST_DIR}/googlemock"
+          )
+         find_package(Threads)
+         target_link_libraries(gtest PUBLIC Threads::Threads)
+        add_library(gtest_main ${UNITTEST_DIR}/UnitTestMain/TestMain.cpp)
+        target_link_libraries(gtest_main PUBLIC gtest)
+      endif()
+      set(FLANG_GTEST_AVAIL 1)
+    else()
+      message(WARNING
+      "Unit-tests will be skipped as LLVM install does not include google-test related headers and libraries.")
+      set(FLANG_GTEST_AVAIL 0)
+    endif()
+  endif()
+  if (FLANG_GTEST_AVAIL)
+    add_custom_target(check-all DEPENDS check-flang FlangUnitTests)
+  else()
+    add_custom_target(check-all DEPENDS check-flang )
+  endif()
   if (LLVM_BUILD_DOCS)
     add_custom_target(doxygen ALL)
   endif()
@@ -139,6 +182,8 @@ else()
   option(FLANG_INCLUDE_TESTS
          "Generate build targets for the Flang unit tests."
          ${LLVM_INCLUDE_TESTS})
+  set(FLANG_GTEST_AVAIL 1)
+
   set(FLANG_BINARY_DIR ${CMAKE_BINARY_DIR}/tools/flang)
   set(BACKEND_PACKAGE_STRING "${PACKAGE_STRING}")
   if (LINK_WITH_FIR)
@@ -344,7 +389,9 @@ add_subdirectory(runtime)
 if (FLANG_INCLUDE_TESTS)
   enable_testing()
   add_subdirectory(test)
-  add_subdirectory(unittests)
+  if (FLANG_GTEST_AVAIL)
+    add_subdirectory(unittests)
+  endif ()
 endif()
 
 option(FLANG_INCLUDE_DOCS "Generate build targets for the Flang docs."

flang/README.md

@@ -140,8 +140,13 @@ cd ~/flang/build
 cmake -DLLVM_DIR=$LLVM -DMLIR_DIR=$MLIR ~/flang/src
 make
 ```
-### How to Run the Regression Tests
+# How to Run Tests
 
+Flang supports 2 different categories of tests
+1. Regression tests (https://www.llvm.org/docs/TestingGuide.html#regression-tests)
+2. Unit tests (https://www.llvm.org/docs/TestingGuide.html#unit-tests)
+
+## For out of tree builds
 To run all tests:
 ```
 cd ~/flang/build
@@ -157,6 +162,38 @@ flang_site_config and flang_config. And they can be set as shown bellow:
  --param flang_site_config=<path-to-flang-build>/test-lit/lit.site.cfg.py \
  --param flang_config=<path-to-flang-build>/test-lit/lit.cfg.py \
   <path-to-fortran-test>
+
+```
+
+Unit tests:
+
+If flang was built with `-DFLANG_INCLUDE_TESTS=On` (`ON` by default), it is possible to generate unittests.
+Note: Unit-tests will be skipped for LLVM install for an out-of-tree build as it does not include googletest related headers and libraries.
+
+There are various ways to run unit-tests.
+
+```
+
+1. make check-flang-unit
+2. make check-all or make check-flang
+3. <path-to-llvm-lit>/llvm-lit \
+        test/Unit
+4. Invoking tests from <out-of-tree flang build>/unittests/<respective unit test folder>
+
+```
+
+
+## For in tree builds
+If flang was built with `-DFLANG_INCLUDE_TESTS=On` (`On` by default), it is possible to
+generate unittests.
+
+To run all of the flang unit tests use the `check-flang-unit` target:
+```
+make check-flang-unit
+```
+To run all of the flang regression tests use the `check-flang` target:
+```
+make check-flang
 ```
 
 # How to Generate Documentation
@@ -179,4 +216,3 @@ It will generate html in
 
     <build-dir>/tools/flang/docs/doxygen/html # for flang docs
 ```
-

flang/test/CMakeLists.txt

@@ -12,6 +12,13 @@ configure_lit_site_cfg(
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.cfg.py
 )
 
+configure_lit_site_cfg(
+  ${CMAKE_CURRENT_SOURCE_DIR}/Unit/lit.site.cfg.py.in
+  ${CMAKE_CURRENT_BINARY_DIR}/Unit/lit.site.cfg.py
+  MAIN_CONFIG
+  ${CMAKE_CURRENT_SOURCE_DIR}/Unit/lit.cfg.py
+)
+
 set(FLANG_TEST_PARAMS
   flang_site_config=${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg.py)
 
@@ -23,6 +30,12 @@ if (LINK_WITH_FIR)
   list(APPEND FLANG_TEST_DEPENDS tco)
 endif()
 
+if (FLANG_INCLUDE_TESTS)
+  if (FLANG_GTEST_AVAIL)
+    list(APPEND FLANG_TEST_DEPENDS FlangUnitTests)
+  endif()
+endif()
+
 add_custom_target(flang-test-depends DEPENDS ${FLANG_TEST_DEPENDS})
 
 add_lit_testsuite(check-flang "Running the Flang regression tests"

flang/test/Unit/lit.cfg.py

@@ -0,0 +1,32 @@
+# -*- Python -*-
+
+# Configuration file for the 'lit' test runner.
+
+import os
+
+import lit.formats
+
+# name: The name of this test suite.
+config.name = 'flang-Unit'
+
+# suffixes: A list of file extensions to treat as test files.
+config.suffixes =  []
+
+# test_source_root: The root path where unit test binaries are located.
+# test_exec_root: The root path where tests should be run.
+config.test_source_root = os.path.join(config.flang_obj_root, 'unittests')
+config.test_exec_root = config.test_source_root
+
+# testFormat: The test format to use to interpret tests.
+config.test_format = lit.formats.GoogleTest(config.llvm_build_mode, 'Tests')
+
+# Tweak the PATH to include the tools dir.
+path = os.path.pathsep.join((config.flang_tools_dir, config.llvm_tools_dir, config.environment['PATH']))
+config.environment['PATH'] = path
+
+path = os.path.pathsep.join((config.flang_libs_dir, config.llvm_libs_dir,
+                              config.environment.get('LD_LIBRARY_PATH','')))
+config.environment['LD_LIBRARY_PATH'] = path
+
+# Propagate PYTHON_EXECUTABLE into the environment
+#config.environment['PYTHON_EXECUTABLE'] = sys.executable

flang/test/Unit/lit.site.cfg.py.in

@@ -0,0 +1,27 @@
+@LIT_SITE_CFG_IN_HEADER@
+
+config.llvm_src_root = "@LLVM_SOURCE_DIR@"
+config.llvm_obj_root = "@LLVM_BINARY_DIR@"
+config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
+config.llvm_libs_dir = "@LLVM_LIBS_DIR@"
+config.llvm_build_mode = "@LLVM_BUILD_MODE@"
+config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
+config.flang_obj_root = "@FLANG_BINARY_DIR@"
+config.flang_src_root = "@FLANG_SOURCE_DIR@"
+config.flang_libs_dir = "@LLVM_LIBRARY_OUTPUT_INTDIR@"
+config.flang_tools_dir = "@LLVM_RUNTIME_OUTPUT_INTDIR@"
+config.target_triple = "@TARGET_TRIPLE@"
+config.python_executable = "@Python3_EXECUTABLE@"
+
+# Support substitution of the tools and libs dirs with user parameters. This is
+# used when we can't determine the tool dir at configuration time.
+try:
+    config.llvm_tools_dir = config.llvm_tools_dir % lit_config.params
+    config.llvm_libs_dir = config.llvm_libs_dir % lit_config.params
+    config.llvm_build_mode = config.llvm_build_mode % lit_config.params
+except KeyError as e:
+    key, = e.args
+    lit_config.fatal("unable to find %r parameter, use '--param=%s=VALUE'" % (key,key))
+
+# Let the main config do the real work.
+lit_config.load_config(config, "@FLANG_SOURCE_DIR@/test/Unit/lit.cfg.py")

flang/unittests/CMakeLists.txt

@@ -1,3 +1,11 @@
+add_custom_target(FlangUnitTests)
+set_target_properties(FlangUnitTests PROPERTIES FOLDER "Flang Unit Tests")
+
+function(add_flang_unittest test_dirname)
+  add_unittest(FlangUnitTests ${test_dirname} ${ARGN})
+endfunction()
+
+add_subdirectory(Optimizer)
 add_subdirectory(Decimal)
 add_subdirectory(Evaluate)
 add_subdirectory(Runtime)

flang/unittests/Optimizer/CMakeLists.txt

@@ -0,0 +1,13 @@
+get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
+
+set(LIBS
+  FIRDialect
+  ${dialect_libs}
+)
+
+add_flang_unittest(FlangOptimizerTests
+  InternalNamesTest.cpp
+)
+target_link_libraries(FlangOptimizerTests
+  PRIVATE
+  ${LIBS})

flang/unittests/Optimizer/InternalNamesTest.cpp

@@ -0,0 +1,20 @@
+//===- InternalNames.cpp - InternalNames unit tests ---------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "flang/Optimizer/Support/InternalNames.h"
+#include "gtest/gtest.h"
+
+using namespace fir;
+using namespace llvm;
+
+TEST(genericName, MyTest) {
+  NameUniquer obj;
+  std::string val = obj.doCommonBlock("hello");
+  std::string val2 = "_QBhello";
+  EXPECT_EQ(val, val2);
+}