[Solaris] detect Solaris LD, use detection results to pass Solaris-ld options

[fedor.sergeev]

Summary

Solaris ld is not the only linker available on Solaris.
Introducing linker detection and using LLVM_LINKER_IS_SOLARISLD to select Solaris-ld specific handling.

[fedor.sergeev]

Tested on Solaris x86/SPARC with gcc and clang setup to run Solari ld.
Tested on Linux x86 with gcc and clang setup to run different kinds of linkers (Gold, Gnu, LLD).

[fedor.sergeev]

Note, that there is also existing code in cmake/modules/HandleLLVMOptions.cmake that runs sorta linker detection for Windows,
as well as setting up variables that describe linker features like LLVM_HAVE_LINK_VERSION_SCRIPT.

Ideally it all should be centralized in one place and handle each and every platform.

I'm not trying to be that ambitious here. Just expanding on what already existed.

[ruiu]

I'm not sure if you need this. At least for https://bugs.llvm.org/show_bug.cgi?id=33698, it seems you can use --color-diagnostics (instead of -color-diagnostics).

[fedor.sergeev]

In D35325#807079, @ruiu wrote:

I'm not sure if you need this. At least for https://bugs.llvm.org/show_bug.cgi?id=33698, it seems you can use --color-diagnostics (instead of -color-diagnostics).

33698 is not the only reason to know "is-Solaris-ld" answer.

There are more places where linker flags are being handled and where SunOS assumed == Solaris-ld, which is wrong:

cmake/modules/AddLLVM.cmake:
      COMMENT "Creating export file for ${target_name}")
      if (${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
        set_property(TARGET ${target_name} APPEND_STRING PROPERTY
                    LINK_FLAGS "  -Wl,-M,${CMAKE_CURRENT_BINARY_DIR}/${native_export_file}")

[ruiu]

It is then perhaps better to add a use of LLVM_LINKER_IS_SOLARISLD to this patch to demonstrate that this patch has at least one usage?

[fedor.sergeev]

In D35325#807140, @ruiu wrote:

It is then perhaps better to add a use of LLVM_LINKER_IS_SOLARISLD to this patch to demonstrate that this patch has at least one usage?

Okey, I thought the preferred way is to break commits into small ones.

[fedor.sergeev]

One usage of LLVM_LINKER_IS_SOLARISLD added.

[ruiu]

LGTM

[fedor.sergeev]

No commit rights yet :(
Somebody, please, commit!

[ruiu]

I'll do that for you.

llvm/trunk/cmake/modules/AddLLVM.cmake

add_custom_command(OUTPUT ${native_export_file}
       COMMAND echo "LLVM_${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR} {" > ${native_export_file}
       COMMAND grep -q "[[:alnum:]]" ${export_file} && echo "  global:" >> ${native_export_file} || :
       COMMAND sed -e "s/$/;/" -e "s/^/    /" < ${export_file} >> ${native_export_file}
       COMMAND echo "  local: *;" >> ${native_export_file}
       COMMAND echo "};" >> ${native_export_file}
       DEPENDS ${export_file}
       VERBATIM
       COMMENT "Creating export file for ${target_name}")
-    if (${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
+    if (${LLVM_LINKER_IS_SOLARISLD})
       set_property(TARGET ${target_name} APPEND_STRING PROPERTY
                    LINK_FLAGS "  -Wl,-M,${CMAKE_CURRENT_BINARY_DIR}/${native_export_file}")
     else()
       set_property(TARGET ${target_name} APPEND_STRING PROPERTY
                    LINK_FLAGS "  -Wl,--version-script,${CMAKE_CURRENT_BINARY_DIR}/${native_export_file}")
     endif()
   else()
     set(native_export_file "${target_name}.def")
function(add_llvm_symbol_exports target_name export_file)
   add_dependencies(${target_name} ${target_name}_exports)
 
   # Add dependency to *_exports later -- CMake issue 14747
   list(APPEND LLVM_COMMON_DEPENDS ${target_name}_exports)
   set(LLVM_COMMON_DEPENDS ${LLVM_COMMON_DEPENDS} PARENT_SCOPE)
 endfunction(add_llvm_symbol_exports)
 
 if(NOT WIN32 AND NOT APPLE)
+  # Detect what linker we have here
   execute_process(
     COMMAND ${CMAKE_C_COMPILER} -Wl,--version
     OUTPUT_VARIABLE stdout
-    ERROR_QUIET
+    ERROR_VARIABLE stderr
     )
+  set(LLVM_LINKER_DETECTED ON)
   if("${stdout}" MATCHES "GNU gold")
     set(LLVM_LINKER_IS_GOLD ON)
+    message(STATUS "Linker detection: GNU Gold")
+  elseif("${stdout}" MATCHES "^LLD")
+    set(LLVM_LINKER_IS_LLD ON)
+    message(STATUS "Linker detection: LLD")
+  elseif("${stdout}" MATCHES "GNU ld")
+    set(LLVM_LINKER_IS_GNULD ON)
+    message(STATUS "Linker detection: GNU ld")
+  elseif("${stderr}" MATCHES "Solaris Link Editors")
+    set(LLVM_LINKER_IS_SOLARISLD ON)
+    message(STATUS "Linker detection: Solaris ld")
+  else()
+    set(LLVM_LINKER_DETECTED OFF)
+    message(STATUS "Linker detection: unknown")
   endif()
 endif()
 
 function(add_link_opts target_name)
   # Don't use linker optimizations in debug builds since it slows down the
   # linker in a context where the optimizations are not important.
   if (NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")