Define CLR specific compiler option CLR_CMAKE_COMPILER

By the time toolchain.cmake is called, the compiler detection from
cmake is not active. We need an intermediate definition to pass
to compiler detection.

Author: franksinankaya

cross/toolchain.cmake

@@ -35,6 +35,15 @@ if(DEFINED ENV{TOOLCHAIN})
   set(TOOLCHAIN $ENV{TOOLCHAIN})
 endif()
 
+# This gets called with CLR_CMAKE_COMPILER set on the first invocation
+# but the cmake variable is not getting populated into other calls.
+# Use environment variable to keep CLR_CMAKE_COMPILER around.
+if (NOT DEFINED CLR_CMAKE_COMPILER)
+  set(CLR_CMAKE_COMPILER $ENV{CLR_CMAKE_COMPILER})
+else()
+  set(ENV{CLR_CMAKE_COMPILER} ${CLR_CMAKE_COMPILER})
+endif()
+
 # Specify include paths
 if(TARGET_ARCH_NAME STREQUAL "armel")
   if(DEFINED TIZEN_TOOLCHAIN)
@@ -62,8 +71,10 @@ endmacro()
 
 # Specify link flags
 add_compile_param(CROSS_LINK_FLAGS "--sysroot=${CROSS_ROOTFS}")
-add_compile_param(CROSS_LINK_FLAGS "--gcc-toolchain=${CROSS_ROOTFS}/usr")
-add_compile_param(CROSS_LINK_FLAGS "--target=${TOOLCHAIN}")
+if (CLR_CMAKE_COMPILER STREQUAL "Clang")
+  add_compile_param(CROSS_LINK_FLAGS "--gcc-toolchain=${CROSS_ROOTFS}/usr")
+  add_compile_param(CROSS_LINK_FLAGS "--target=${TOOLCHAIN}")
+endif()
 
 add_compile_param(CROSS_LINK_FLAGS "-fuse-ld=gold")
 
@@ -84,8 +95,10 @@ add_compile_param(CMAKE_MODULE_LINKER_FLAGS "${CROSS_LINK_FLAGS}" "TOOLCHAIN_EXE
 
 # Specify compile options
 add_compile_options("--sysroot=${CROSS_ROOTFS}")
-add_compile_options("--target=${TOOLCHAIN}")
-add_compile_options("--gcc-toolchain=${CROSS_ROOTFS}/usr")
+if (CLR_CMAKE_COMPILER STREQUAL "Clang")
+  add_compile_options("--target=${TOOLCHAIN}")
+  add_compile_options("--gcc-toolchain=${CROSS_ROOTFS}/usr")
+endif()
 
 if(TARGET_ARCH_NAME MATCHES "^(arm|armel|arm64)$")
   set(CMAKE_C_COMPILER_TARGET ${TOOLCHAIN})

src/pal/tools/gen-buildsys-clang.sh

@@ -162,6 +162,7 @@ cmake \
   "-DCMAKE_BUILD_TYPE=$buildtype" \
   "-DCMAKE_EXPORT_COMPILE_COMMANDS=1 " \
   "-DCLR_CMAKE_ENABLE_CODE_COVERAGE=$code_coverage" \
+  "-DCLR_CMAKE_COMPILER=Clang" \
   $cmake_extra_defines \
   $__UnprocessedCMakeArgs \
   "$1"

src/pal/tools/gen-buildsys-gcc.sh

@@ -182,6 +182,7 @@ cmake \
   "-DCMAKE_BUILD_TYPE=$buildtype" \
   "-DCMAKE_EXPORT_COMPILE_COMMANDS=1 " \
   "-DCLR_CMAKE_ENABLE_CODE_COVERAGE=$code_coverage" \
+  "-DCLR_CMAKE_COMPILER=GNU" \
   $cmake_extra_defines \
   $__UnprocessedCMakeArgs \
   "$1"