Languages: Add support for Objective-C

Add entries in Modules and Modules/Platform to support
Objective-C compiler determination and identification.
Add Modules to check Objective-C compiler flags, source
compilations, program checks, etc...

Use OBJC as the designator of the language, eg:

project(foo OBJC)

Add various tests for Objective-C language features.  Add
tests to preserve C++ handling of .m and .mm files when
OBJC is not a configured language.

Co-Authored-By: Cristian Adam <cristian.adam@gmail.com>

14 files changed, 183 insertions, 2 deletions

diff --git a/Tests/CMakeLists.txt b/Tests/CMakeLists.txt
index c284603..2e17e59 100644
--- a/Tests/CMakeLists.txt
+++ b/Tests/CMakeLists.txt
@@ -2328,6 +2328,43 @@ ${CMake_SOURCE_DIR}/Utilities/Release/push.bash --dir dev -- '${CMake_BUILD_NIGH
       list(APPEND TEST_BUILD_DIRS "${CMake_BINARY_DIR}/Tests/CFBundleTest")
 
       ADD_TEST_MACRO(ObjC++ ObjC++)
+
+      add_test(Objective-C.simple-build-test ${CMAKE_CTEST_COMMAND}
+        --build-and-test
+        "${CMake_SOURCE_DIR}/Tests/Objective-C/simple-build-test"
+        "${CMake_BINARY_DIR}/Tests/Objective-C/simple-build-test"
+        --build-two-config
+        ${build_generator_args}
+        --build-project simple-build-test
+        --build-options ${build_options}
+        --test-command simple-build-test
+      )
+      list(APPEND TEST_BUILD_DIRS "${CMake_BINARY_DIR}/Tests/Objective-C/simple-build-test")
+
+      add_test(Objective-C.c-file-extension-test ${CMAKE_CTEST_COMMAND}
+        --build-and-test
+        "${CMake_SOURCE_DIR}/Tests/Objective-C/c-file-extension-test"
+        "${CMake_BINARY_DIR}/Tests/Objective-C/c-file-extension-test"
+        --build-two-config
+        ${build_generator_args}
+        --build-project c-file-extension-test
+        --build-options ${build_options}
+        --test-command c-file-extension-test
+      )
+      list(APPEND TEST_BUILD_DIRS "${CMake_BINARY_DIR}/Tests/Objective-C/c-file-extension-test")
+
+      add_test(Objective-C.objc-file-extension-test ${CMAKE_CTEST_COMMAND}
+        --build-and-test
+        "${CMake_SOURCE_DIR}/Tests/Objective-C/objc-file-extension-test"
+        "${CMake_BINARY_DIR}/Tests/Objective-C/objc-file-extension-test"
+        --build-two-config
+        ${build_generator_args}
+        --build-project objc-file-extension-test
+        --build-options ${build_options}
+        --test-command objc-file-extension-test
+      )
+      list(APPEND TEST_BUILD_DIRS "${CMAKE_BINARY_DIR}/Tests/Objective-C/objc-file-extension-test")
+
     endif ()
   endif ()
 
diff --git a/Tests/CMakeOnly/CMakeLists.txt b/Tests/CMakeOnly/CMakeLists.txt
index 19f3f79..1a25469 100644
--- a/Tests/CMakeOnly/CMakeLists.txt
+++ b/Tests/CMakeOnly/CMakeLists.txt
@@ -30,6 +30,12 @@ add_CMakeOnly_test(CheckStructHasMember)
 
 add_CMakeOnly_test(CompilerIdC)
 add_CMakeOnly_test(CompilerIdCXX)
+
+if(CMAKE_OBJC_COMPILER)
+  add_CMakeOnly_test(CompilerIdOBJC)
+  add_CMakeOnly_test(CheckOBJCCompilerFlag)
+endif()
+
 if(CMAKE_Fortran_COMPILER)
   add_CMakeOnly_test(CompilerIdFortran)
 endif()
diff --git a/Tests/CMakeOnly/CheckLanguage/CMakeLists.txt b/Tests/CMakeOnly/CheckLanguage/CMakeLists.txt
index ca4becb..e9bdf6a 100644
--- a/Tests/CMakeOnly/CheckLanguage/CMakeLists.txt
+++ b/Tests/CMakeOnly/CheckLanguage/CMakeLists.txt
@@ -5,10 +5,19 @@ include(CheckLanguage)
 set(langs )
 set(expect_C 1)
 set(expect_CXX 1)
+if(APPLE)
+  set(expect_OBJC 1)
+endif()
 unset(expect_Fortran)
 set(expect_NoSuchLanguage 0)
 
-foreach(lang C CXX Fortran CUDA NoSuchLanguage)
+set(LANGUAGES C CXX Fortran CUDA NoSuchLanguage)
+
+if(APPLE)
+  list(APPEND LANGUAGES OBJC)
+endif()
+
+foreach(lang ${LANGUAGES})
   check_language(${lang})
   if(NOT DEFINED CMAKE_${lang}_COMPILER)
     message(FATAL_ERROR "check_language(${lang}) did not set result")
diff --git a/Tests/CMakeOnly/CheckOBJCCompilerFlag/CMakeLists.txt b/Tests/CMakeOnly/CheckOBJCCompilerFlag/CMakeLists.txt
new file mode 100644
index 0000000..a9a96ee
--- /dev/null
+++ b/Tests/CMakeOnly/CheckOBJCCompilerFlag/CMakeLists.txt
@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 2.8.12)
+
+project(CheckOBJCCompilerFlag)
+
+include(CheckOBJCCompilerFlag)
+
+if(CMAKE_COMPILER_IS_GNUOBJC)
+  set(COMPILER_FLAG -fobjc-direct-dispatch)
+else()
+  set(COMPILER_FLAG -fobjc-gc)
+endif()
+
+CHECK_OBJC_COMPILER_FLAGS(${COMPILER_FLAG} HAS_COMPILER_FLAG)
+
+if(NOT HAS_COMPILER_FLAG)
+  message(SEND_ERROR "Test fail: HAS_COMPILER_FLAG: ${COMPILER_FLAG}")
+endif
diff --git a/Tests/CMakeOnly/CompilerIdOBJC/CMakeLists.txt b/Tests/CMakeOnly/CompilerIdOBJC/CMakeLists.txt
new file mode 100644
index 0000000..8f13787
--- /dev/null
+++ b/Tests/CMakeOnly/CompilerIdOBJC/CMakeLists.txt
@@ -0,0 +1,14 @@
+cmake_minimum_required(VERSION 2.8.12)
+project(CompilerIdOBJC OBJC)
+
+foreach(v
+    CMAKE_OBJC_COMPILER
+    CMAKE_OBJC_COMPILER_ID
+    CMAKE_OBJC_COMPILER_VERSION
+    )
+  if(${v})
+    message(STATUS "${v}=[${${v}}]")
+  else()
+    message(SEND_ERROR "${v} not set!")
+  endif()
+endforeach()
diff --git a/Tests/Objective-C/c-file-extension-test/CMakeLists.txt b/Tests/Objective-C/c-file-extension-test/CMakeLists.txt
new file mode 100644
index 0000000..e091448
--- /dev/null
+++ b/Tests/Objective-C/c-file-extension-test/CMakeLists.txt
@@ -0,0 +1,5 @@
+cmake_minimum_required(VERSION 3.15)
+
+project(c-file-extension-test C)
+
+add_executable(c-file-extension-test main.m)
diff --git a/Tests/Objective-C/c-file-extension-test/main.m b/Tests/Objective-C/c-file-extension-test/main.m
new file mode 100644
index 0000000..1c159a9
--- /dev/null
+++ b/Tests/Objective-C/c-file-extension-test/main.m
@@ -0,0 +1,8 @@
+#ifndef __OBJC__
+#  error "Compiler cannot compile Objective-C"
+#endif
+
+int main()
+{
+  return 0;
+}
diff --git a/Tests/Objective-C/objc-file-extension-test/CMakeLists.txt b/Tests/Objective-C/objc-file-extension-test/CMakeLists.txt
new file mode 100644
index 0000000..27e88be
--- /dev/null
+++ b/Tests/Objective-C/objc-file-extension-test/CMakeLists.txt
@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.15)
+
+project(objc-file-extension-test OBJC CXX)
+
+add_executable(objc-file-extension-test main.m)
+target_link_libraries(objc-file-extension-test "-framework Foundation")
diff --git a/Tests/Objective-C/objc-file-extension-test/main.m b/Tests/Objective-C/objc-file-extension-test/main.m
new file mode 100644
index 0000000..2ec3917
--- /dev/null
+++ b/Tests/Objective-C/objc-file-extension-test/main.m
@@ -0,0 +1,12 @@
+#ifndef __OBJC__
+#  error "Compiler is not an Objective-C compiler."
+#endif
+
+#import <Foundation/Foundation.h>
+
+int main()
+{
+  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+  [pool release];
+  return 0;
+}
diff --git a/Tests/Objective-C/simple-build-test/CMakeLists.txt b/Tests/Objective-C/simple-build-test/CMakeLists.txt
new file mode 100644
index 0000000..5ab46ac
--- /dev/null
+++ b/Tests/Objective-C/simple-build-test/CMakeLists.txt
@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 3.15)
+
+set(CMAKE_MACOSX_RPATH OFF)
+
+project(simple-build-test OBJC)
+
+add_library(foo SHARED foo.m)
+target_link_libraries(foo "-framework Foundation")
+
+add_executable(simple-build-test main.m)
+target_link_libraries(simple-build-test "-framework Foundation" foo)
diff --git a/Tests/Objective-C/simple-build-test/foo.h b/Tests/Objective-C/simple-build-test/foo.h
new file mode 100644
index 0000000..b3fb084
--- /dev/null
+++ b/Tests/Objective-C/simple-build-test/foo.h
@@ -0,0 +1,9 @@
+#import <Foundation/Foundation.h>
+
+@interface Foo : NSObject {
+  NSNumber* age;
+}
+
+@property (nonatomic, retain) NSNumber* age;
+
+@end
diff --git a/Tests/Objective-C/simple-build-test/foo.m b/Tests/Objective-C/simple-build-test/foo.m
new file mode 100644
index 0000000..2d452a8
--- /dev/null
+++ b/Tests/Objective-C/simple-build-test/foo.m
@@ -0,0 +1,7 @@
+#import "foo.h"
+
+@implementation Foo
+
+@synthesize age;
+
+@end
diff --git a/Tests/Objective-C/simple-build-test/main.m b/Tests/Objective-C/simple-build-test/main.m
new file mode 100644
index 0000000..970d554
--- /dev/null
+++ b/Tests/Objective-C/simple-build-test/main.m
@@ -0,0 +1,12 @@
+#import <Foundation/Foundation.h>
+#import "foo.h"
+
+int main(int argc, char **argv)
+{
+  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+  Foo *theFoo = [[Foo alloc] init];
+  theFoo.age = [NSNumber numberWithInt:argc];
+  NSLog(@"%d\n",[theFoo.age intValue]);
+  [pool release];
+  return 0;
+}
diff --git a/Tests/TryCompile/CMakeLists.txt b/Tests/TryCompile/CMakeLists.txt
index 54e96a2..8fd8090 100644
--- a/Tests/TryCompile/CMakeLists.txt
+++ b/Tests/TryCompile/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required (VERSION 2.6)
-project(TryCompile)
+project(TryCompile OBJC C CXX)
 
 macro(TEST_ASSERT value msg)
   if (NOT ${value})
@@ -313,6 +313,34 @@ if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
   TEST_ASSERT(C_STRICT_PROTOTYPES "CHECK_C_COMPILER_FLAG failed -Werror -Wstrict-prototypes")
 endif()
 
+#########################################################################
+#
+# Test that the CHECK_OBJCC_SOURCE_COMPILES, CHECK_OBJC_SOURCE_RUNS
+# macros work.
+
+include(CheckOBJCSourceCompiles)
+include(CheckOBJCSourceRuns)
+
+CHECK_OBJC_SOURCE_COMPILES("I don't build in Objective-C" OBJC_BUILD_SHOULD_FAIL)
+CHECK_OBJC_SOURCE_COMPILES("int main() { return 0; }" SIMPLE_OBJC_BUILD_SHOULD_WORK)
+
+TEST_FAIL(OBJC_BUILD_SHOULD_FAIL "CHECK_OBJC_SOURCE_COMPILES() succeeded, but should have failed")
+TEST_ASSERT(SIMPLE_OBJC_BUILD_SHOULD_WORK "CHECK_OBJC_SOURCE_COMPILES() failed, but should have succeeded")
+
+set(CMAKE_REQUIRED_LIBRARIES "-framework Foundation")
+
+CHECK_OBJC_SOURCE_COMPILES("#import <Foundation/Foundation.h>\nint main()\n{\nNSObject *foo;\nreturn 0;\n}\n" OBJC_BUILD_SHOULD_WORK)
+CHECK_OBJC_SOURCE_RUNS("int main() { return 2; }" SIMPLE_OBJC_RUN_SHOULD_FAIL)
+CHECK_OBJC_SOURCE_RUNS("int main() { return 0; }" SIMPLE_OBJC_RUN_SHOULD_WORK)
+CHECK_OBJC_SOURCE_RUNS("#import <Foundation/Foundation.h>\nint main()\n{\nNSObject *foo;\nreturn 2;\n}\n" OBJC_RUN_SHOULD_FAIL)
+CHECK_OBJC_SOURCE_RUNS("#import <Foundation/Foundation.h>\nint main()\n{\nNSObject *foo;\nreturn 0;\n}\n" OBJC_RUN_SHOULD_WORK)
+
+TEST_ASSERT(OBJC_BUILD_SHOULD_WORK "CHECK_OBJC_SOURCE_COMPILES() failed, but should have succeeded")
+TEST_FAIL(SIMPLE_OBJC_RUN_SHOULD_FAIL "CHECK_OBJC_SOURC_RUNS() succeeds, but should have failed")
+TEST_ASSERT(SIMPLE_OBJC_RUN_SHOULD_WORK "CHECK_OBJC_SOURCE_RUNS() failed, but should have succeeded")
+TEST_FAIL(OBJC_RUN_SHOULD_FAIL "CHECK_OBJC_SOURCE_RUNS() succeeds, but should have failed")
+TEST_ASSERT(OBJC_RUN_SHOULD_WORK "CHECK_OBJC_SOURCE_RUNS() failed, but should have succeeded")
+
 #######################################################################
 #
 # also test that the check_prototype_definition macro works