Set up AIX XLClang flags for CMake builds

The new compiler ID XLClang is for CMake 3.15 and beyond.

[skip ci]

Signed-off-by: Sharon Wang <sharon-wang-cpsc@outlook.com>

Co-authored-by: Devin Nakamura <devinn@ca.ibm.com>

cmake/modules/OmrCompilerSupport.cmake

@@ -1,5 +1,5 @@
 ###############################################################################
-# Copyright (c) 2017, 2020 IBM Corp. and others
+# Copyright (c) 2017, 2021 IBM Corp. and others
 #
 # This program and the accompanying materials are made available under
 # the terms of the Eclipse Public License 2.0 which accompanies this
@@ -108,7 +108,7 @@ function(ppc_spp2s_files out_var compiler)
 			file(MAKE_DIRECTORY ${out_dir}) # just in case it doesn't exist already
 
 			add_custom_command(OUTPUT ${ipp_out_f}
-				COMMAND ${SPP_CMD} ${SPP_FLAGS} ${SPP_DEFINES} ${SPP_INCLUDES} -E -P ${absolute_in_f} > ${ipp_out_f}
+				COMMAND ${SPP_CMD} ${SPP_FLAGS} ${SPP_DEFINES} ${SPP_INCLUDES} ${absolute_in_f} > ${ipp_out_f}
 				DEPENDS ${in_f}
 				WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
 				COMMENT "Running preprocessing ${in_f} to create ${ipp_out_f}"

cmake/modules/OmrDetectSystemInformation.cmake

@@ -1,5 +1,5 @@
 ###############################################################################
-# Copyright (c) 2017, 2020 IBM Corp. and others
+# Copyright (c) 2017, 2021 IBM Corp. and others
 #
 # This program and the accompanying materials are made available under
 # the terms of the Eclipse Public License 2.0 which accompanies this
@@ -75,7 +75,7 @@ endfunction()
 
 # Translate from CMake's view of the system to the OMR view of the system.
 # Exports a number of variables indicating platform, os, endianness, etc.
-# - OMR_ARCH_{AARCH64,X86,ARM,S390} # TODO: Add POWER
+# - OMR_ARCH_{AARCH64,X86,ARM,S390,POWER}
 # - OMR_ENV_DATA{32,64}
 # - OMR_ENV_TARGET_DATASIZE (either 32 or 64)
 # - OMR_ENV_LITTLE_ENDIAN
@@ -198,8 +198,17 @@ macro(omr_detect_system_information)
 				# just use GNU config
 				set(_OMR_TOOLCONFIG "gnu")
 			endif()
-		elseif(CMAKE_C_COMPILER_ID STREQUAL "XL" OR CMAKE_C_COMPILER_ID STREQUAL "zOS")
+		elseif(CMAKE_C_COMPILER_ID MATCHES "^XL(Clang)?$" OR CMAKE_C_COMPILER_ID STREQUAL "zOS")
+			# In CMake 3.14 and prior, XLClang uses CMAKE_C_COMPILER_ID "XL"
+			# In CMake 3.15 and beyond, XLClang uses CMAKE_C_COMPILER_ID "XLClang"
 			set(_OMR_TOOLCONFIG "xlc")
+			if(CMAKE_C_COMPILER MATCHES ".*xlclang$")
+				# Checking the CMAKE_C_COMPILER command is necessary to determine if XLClang is
+				# the compiler, since XLClang might have CMAKE_C_COMPILER_ID "XL" or "XLClang"
+				# depending on the CMake version. Without this check, it's ambiguous whether the
+				# compiler is XLC or XLClang.
+				set(CMAKE_C_COMPILER_IS_XLCLANG TRUE CACHE BOOL "XLClang is the C compiler")
+			endif()
 		else()
 			message(FATAL_ERROR "OMR: Unknown compiler ID: '${CMAKE_CXX_COMPILER_ID}'")
 		endif()

cmake/modules/ddr/DDRSetStub.cmake.in

@@ -1,5 +1,5 @@
 ###############################################################################
-# Copyright (c) 2019, 2020 IBM Corp. and others
+# Copyright (c) 2019, 2021 IBM Corp. and others
 #
 # This program and the accompanying materials are made available under
 # the terms of the Eclipse Public License 2.0 which accompanies this
@@ -141,6 +141,12 @@ function(process_source_files src_files)
 		)
 
 		set(pp_command "@CMAKE_C_COMPILER@")
+		if("@CMAKE_C_COMPILER_IS_XLCLANG@")
+			# XLClang seems to have trouble with *.h and *.hpp files here, claiming:
+			# "error: invalid argument '-std=gnu++0x' not allowed with 'C/ObjC'"
+			# Adding this option to the command alleviates this issue.
+			list(APPEND pp_command "-xc++")
+		endif()
 		list(APPEND pp_command ${BASE_ARGS} "-E" "${stub_file}")
 		add_custom_command(
 			OUTPUT "${annt_file}"

cmake/modules/platform/toolcfg/xlc.cmake

@@ -1,5 +1,5 @@
 ###############################################################################
-# Copyright (c) 2017, 2020 IBM Corp. and others
+# Copyright (c) 2017, 2021 IBM Corp. and others
 #
 # This program and the accompanying materials are made available under
 # the terms of the Eclipse Public License 2.0 which accompanies this
@@ -19,6 +19,17 @@
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
 ###############################################################################
 
+if(CMAKE_C_COMPILER_IS_XLCLANG)
+	macro(omr_toolconfig_global_setup)
+		# For XLClang, remove any usages of -qhalt=e or -qhalt=s provided by default
+		# in the CMAKE CXX/C/ASM FLAGS, since xlclang/xlclang++ are not compatible
+		# with the e or s options.
+		omr_remove_flags(CMAKE_ASM_FLAGS -qhalt=e)
+		omr_remove_flags(CMAKE_CXX_FLAGS -qhalt=s)
+		omr_remove_flags(CMAKE_C_FLAGS   -qhalt=e)
+	endmacro(omr_toolconfig_global_setup)
+endif()
+
 if(OMR_HOST_ARCH STREQUAL "ppc")
 	set(OMR_WARNING_AS_ERROR_FLAG -qhalt=w)
 
@@ -53,23 +64,36 @@ if(OMR_HOST_ARCH STREQUAL "ppc")
 	list(APPEND TR_COMPILE_OPTIONS
 		-qarch=pwr7
 		-qtls
-		-qnotempinc
-		-qenum=small
-		-qmbcs
 		-qfuncsect
 		-qsuppress=1540-1087:1540-1088:1540-1090:1540-029:1500-029
 		-qdebug=nscrep
 	)
 
+	if(NOT CMAKE_C_COMPILER_IS_XLCLANG)
+		# xlc/xlc++ options
+		list(APPEND TR_COMPILE_OPTIONS
+			-qnotempinc
+			-qenum=small
+			-qmbcs
+		)
+	endif()
+
 	# Configure the platform dependent library for multithreading
 	set(OMR_PLATFORM_THREAD_LIBRARY -lpthread)
 endif()
 
 if(OMR_OS_AIX)
-	list(APPEND OMR_PLATFORM_COMPILE_OPTIONS -qinfo=pro)
 	list(APPEND OMR_PLATFORM_C_COMPILE_OPTIONS -qlanglvl=extended)
 	list(APPEND OMR_PLATFORM_CXX_COMPILE_OPTIONS -qlanglvl=extended0x)
 
+	if(CMAKE_C_COMPILER_IS_XLCLANG)
+		# xlclang/xlclang++ options
+		list(APPEND OMR_PLATFORM_COMPILE_OPTIONS -qxlcompatmacros)
+	else()
+		# xlc/xlc++ options
+		list(APPEND OMR_PLATFORM_COMPILE_OPTIONS -qinfo=pro)
+	endif()
+
 	set(CMAKE_CXX_STANDARD_LIBRARIES "${CMAKE_CXX_STANDARD_LIBRARIES} -lm -liconv -ldl -lperfstat")
 
 	if(OMR_ENV_DATA64)
@@ -177,7 +201,16 @@ elseif(OMR_OS_ZOS)
 endif()
 
 set(SPP_CMD ${CMAKE_C_COMPILER})
-set(SPP_FLAGS -E -P)
+
+if(CMAKE_C_COMPILER_IS_XLCLANG)
+	# xlclang/xlclang++ options
+	# The -P option doesn't sit well with XLClang, so it's not included. It causes:
+	# "ld: 0711-317 ERROR: Undefined symbol: <SYMBOL>" when libj9jit29.so is getting linked.
+	set(SPP_FLAGS -E)
+else()
+	# xlc/xlc++ options
+	set(SPP_FLAGS -E -P)
+endif()
 
 if(OMR_OS_ZOS)
 	function(_omr_toolchain_process_exports TARGET_NAME)