[libFuzzer] Use the compiler to link the relocatable object

Rather than invoking the linker directly, let the compiler driver
handle it. This ensures that we use the correct linker in the case
of cross-compiling.

Differential Revision: https://reviews.llvm.org/D127828

diff --git a/compiler-rt/lib/fuzzer/CMakeLists.txt b/compiler-rt/lib/fuzzer/CMakeLists.txt
index d51de53..856cd73 100644 (file)
--- a/compiler-rt/lib/fuzzer/CMakeLists.txt
+++ b/compiler-rt/lib/fuzzer/CMakeLists.txt
@@ -138,15 +138,15 @@ if(OS_NAME MATCHES "Linux|Fuchsia" AND
    COMPILER_RT_LIBCXX_PATH AND
    COMPILER_RT_LIBCXXABI_PATH)
   macro(partially_link_libcxx name dir arch)
-    if(${arch} MATCHES "i386")
-      set(EMULATION_ARGUMENT "-m" "elf_i386")
-    else()
-      set(EMULATION_ARGUMENT "")
+    get_target_flags_for_arch(${arch} target_cflags)
+    if(CMAKE_CXX_COMPILER_ID MATCHES Clang)
+      get_compiler_rt_target(${arch} target)
+      set(target_cflags "--target=${target} ${target_cflags}")
     endif()
     set(cxx_${arch}_merge_dir "${CMAKE_CURRENT_BINARY_DIR}/cxx_${arch}_merge.dir")
     file(MAKE_DIRECTORY ${cxx_${arch}_merge_dir})
     add_custom_command(TARGET clang_rt.${name}-${arch} POST_BUILD
-      COMMAND ${CMAKE_LINKER} ${EMULATION_ARGUMENT} --whole-archive "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>" --no-whole-archive ${dir}/lib/libc++.a -r -o ${name}.o
+      COMMAND ${CMAKE_CXX_COMPILER} ${target_cflags} -Wl,--whole-archive "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>" -Wl,--no-whole-archive ${dir}/lib/libc++.a -r -o ${name}.o
       COMMAND ${CMAKE_OBJCOPY} --localize-hidden ${name}.o
       COMMAND ${CMAKE_COMMAND} -E remove "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>"
       COMMAND ${CMAKE_AR} qcs "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>" ${name}.o