[CMake] Add support for building on illumos

illumos has an older version of the Solaris linker that does not
support the GNU version script compat nor version scripts and does
not support -Bsymbolic-functions. Treat illumos linker separately.

The libclang/CMakeLists part lifted from NetBSD's pkgsrc.

Author: brad0

clang/tools/clang-shlib/CMakeLists.txt

@@ -50,7 +50,7 @@ add_clang_library(clang-cpp
                   ${_DEPS})
 # Optimize function calls for default visibility definitions to avoid PLT and
 # reduce dynamic relocations.
-if (NOT APPLE AND NOT MINGW)
+if (NOT APPLE AND NOT MINGW AND NOT LLVM_LINKER_IS_SOLARISLD_ILLUMOS)
   target_link_options(clang-cpp PRIVATE LINKER:-Bsymbolic-functions)
 endif()
 if (MINGW OR CYGWIN)

clang/tools/libclang/CMakeLists.txt

@@ -185,11 +185,22 @@ if(ENABLE_SHARED)
     endif()
   endif()
   if (USE_VERSION_SCRIPT)
-    target_link_options(libclang PRIVATE "-Wl,--version-script,${CMAKE_CURRENT_SOURCE_DIR}/libclang.map")
-    # The Solaris 11.4 linker supports a subset of GNU ld version scripts,
-    # but requires a special option to enable it.
     if (${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
-      target_link_options(libclang PRIVATE "-Wl,-z,gnu-version-script-compat")
+      include(CheckLinkerFlag)
+      # The Solaris 11.4 linker supports a subset of GNU ld version scripts,
+      # but requires a special option to enable it.
+      llvm_check_linker_flag(CXX "-Wl,-z,gnu-version-script-compat"
+                             LINKER_SUPPORTS_Z_GNU_VERSION_SCRIPT_COMPAT)
+      # Older Solaris (and illumos) linker does not support GNU ld version scripts
+      # and does not support GNU version script compat.
+      if (LINKER_SUPPORTS_Z_GNU_VERSION_SCRIPT_COMPAT)
+        target_link_options(libclang PRIVATE "-Wl,--version-script,${CMAKE_CURRENT_SOURCE_DIR}/libclang.map")
+        target_link_options(libclang PRIVATE "-Wl,-z,gnu-version-script-compat")
+      else()
+        target_link_options(libclang PRIVATE "-Wl,-M,${CMAKE_CURRENT_SOURCE_DIR}/libclang.map")
+      endif()
+    else()
+      target_link_options(libclang PRIVATE "-Wl,--version-script,${CMAKE_CURRENT_SOURCE_DIR}/libclang.map")
     endif()
     # Ensure that libclang.so gets rebuilt when the linker script changes.
     set_property(SOURCE ARCMigrate.cpp APPEND PROPERTY

llvm/cmake/modules/AddLLVM.cmake

@@ -241,6 +241,12 @@ if (NOT DEFINED LLVM_LINKER_DETECTED AND NOT WIN32)
       set(LLVM_LINKER_DETECTED YES CACHE INTERNAL "")
       set(LLVM_LINKER_IS_GNULD YES CACHE INTERNAL "")
       message(STATUS "Linker detection: GNU ld")
+    elseif("${stderr}" MATCHES "(illumos)" OR
+           "${stdout}" MATCHES "(illumos)")
+      set(LLVM_LINKER_DETECTED YES CACHE INTERNAL "")
+      set(LLVM_LINKER_IS_SOLARISLD YES CACHE INTERNAL "")
+      set(LLVM_LINKER_IS_SOLARISLD_ILLUMOS YES CACHE INTERNAL "")
+      message(STATUS "Linker detection: Solaris ld (illumos)")
     elseif("${stderr}" MATCHES "Solaris Link Editors" OR
            "${stdout}" MATCHES "Solaris Link Editors")
       set(LLVM_LINKER_DETECTED YES CACHE INTERNAL "")

llvm/tools/llvm-shlib/CMakeLists.txt

@@ -49,7 +49,7 @@ if(LLVM_BUILD_LLVM_DYLIB)
       # Solaris ld does not accept global: *; so there is no way to version *all* global symbols
       set(LIB_NAMES -Wl,--version-script,${LLVM_LIBRARY_DIR}/tools/llvm-shlib/simple_version_script.map ${LIB_NAMES})
     endif()
-    if (NOT MINGW)
+    if (NOT MINGW AND NOT LLVM_LINKER_IS_SOLARISLD_ILLUMOS)
       # Optimize function calls for default visibility definitions to avoid PLT and
       # reduce dynamic relocations.
       # Note: for -fno-pic default, the address of a function may be different from