[SystemZ/ZOS] Additions to the build system. (#74730)

This change extend the CMake files with the necessary additions to build LLVM for z/OS.

Author: abhina-sree

llvm/CMakeLists.txt

@@ -581,7 +581,9 @@ set(LLVM_TARGETS_TO_BUILD
    ${LLVM_EXPERIMENTAL_TARGETS_TO_BUILD})
 list(REMOVE_DUPLICATES LLVM_TARGETS_TO_BUILD)
 
-option(LLVM_ENABLE_PIC "Build Position-Independent Code" ON)
+if (NOT CMAKE_SYSTEM_NAME MATCHES "OS390")
+  option(LLVM_ENABLE_PIC "Build Position-Independent Code" ON)
+endif()
 option(LLVM_ENABLE_MODULES "Compile with C++ modules enabled." OFF)
 if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
   option(LLVM_ENABLE_MODULE_DEBUGGING "Compile with -gmodules." ON)
@@ -1127,6 +1129,8 @@ if (CMAKE_SYSTEM_NAME MATCHES "OS390")
   add_compile_definitions(_XOPEN_SOURCE=600)
   add_compile_definitions(_OPEN_SYS) # Needed for process information.
   add_compile_definitions(_OPEN_SYS_FILE_EXT) # Needed for EBCDIC I/O.
+  add_compile_definitions(_EXT) # Needed for file data.
+  add_compile_definitions("-D_UNIX03_THREADS") # Multithreading support.
 endif()
 
 # Build with _FILE_OFFSET_BITS=64 on Solaris to match g++ >= 9.

llvm/lib/Transforms/Hello/CMakeLists.txt

@@ -6,7 +6,7 @@ if( NOT LLVM_REQUIRES_RTTI )
   endif()
 endif()
 
-if(WIN32 OR CYGWIN)
+if(WIN32 OR CYGWIN OR ZOS)
   set(LLVM_LINK_COMPONENTS Core Support)
 endif()
 

llvm/tools/bugpoint-passes/CMakeLists.txt

@@ -10,7 +10,7 @@ if( NOT LLVM_REQUIRES_RTTI )
   endif()
 endif()
 
-if(WIN32 OR CYGWIN)
+if(WIN32 OR CYGWIN OR ZOS)
   set(LLVM_LINK_COMPONENTS Core Support)
 endif()
 

llvm/tools/llvm-shlib/CMakeLists.txt

@@ -14,6 +14,9 @@ if(LLVM_BUILD_LLVM_DYLIB)
   if(MSVC)
     message(FATAL_ERROR "Generating libLLVM is not supported on MSVC")
   endif()
+  if(ZOS)
+    message(FATAL_ERROR "Generating libLLVM is not supported on z/OS")
+  endif()
 
   llvm_map_components_to_libnames(LIB_NAMES ${LLVM_DYLIB_COMPONENTS})