[llvm] r320138 - [cmake] Make setting of CMAKE_C(XX)_COMPILER flags overridable for cross-builds

[Pavel Labath via llvm-commits]

Author: labath
Date: Fri Dec  8 01:59:48 2017
New Revision: 320138

URL: http://llvm.org/viewvc/llvm-project?rev=320138&view=rev
Log:
[cmake] Make setting of CMAKE_C(XX)_COMPILER flags overridable for cross-builds

Summary:
r319898 made it possible to override these variables via the
CROSS_TOOLCHAIN_FLAGS setting, but this only worked if one explicitly
specifies these variables there. If, instead, one uses
CROSS_TOOLCHAIN_FLAGS to specify a toolchain file (as our internal
builds do, to point cmake to a checked-in toolchain), the
CMAKE_C(XX)_COMPILER flags would still win over the ones specified by
the toolchain file.

To fix is to make the mere presence of these flags overridable. I do
this by putting them as a default value for the CROSS_TOOLCHAIN_FLAGS
setting, so they can be overridden at cmake configuration time.

Reviewers: hintonda, beanz

Subscribers: bogner, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D40947

Modified:
    llvm/trunk/cmake/modules/CrossCompile.cmake

Modified: llvm/trunk/cmake/modules/CrossCompile.cmake
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/cmake/modules/CrossCompile.cmake?rev=320138&r1=320137&r2=320138&view=diff
==============================================================================
--- llvm/trunk/cmake/modules/CrossCompile.cmake (original)
+++ llvm/trunk/cmake/modules/CrossCompile.cmake Fri Dec  8 01:59:48 2017
@@ -7,10 +7,16 @@ function(llvm_create_cross_target_intern
   endif(NOT DEFINED LLVM_${target_name}_BUILD)
 
   if (EXISTS ${LLVM_MAIN_SRC_DIR}/cmake/platforms/${toolchain}.cmake)
-    set(CROSS_TOOLCHAIN_FLAGS_${target_name} 
-        -DCMAKE_TOOLCHAIN_FILE=\"${LLVM_MAIN_SRC_DIR}/cmake/platforms/${toolchain}.cmake\"
-        CACHE STRING "Toolchain file for ${target_name}")
+    set(CROSS_TOOLCHAIN_FLAGS_INIT
+      -DCMAKE_TOOLCHAIN_FILE=\"${LLVM_MAIN_SRC_DIR}/cmake/platforms/${toolchain}.cmake\")
+  else()
+    set(CROSS_TOOLCHAIN_FLAGS_INIT
+      -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
+      -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
+      )
   endif()
+  set(CROSS_TOOLCHAIN_FLAGS_${target_name} ${CROSS_TOOLCHAIN_FLAGS_INIT}
+    CACHE STRING "Toolchain configuration for ${target_name}")
 
   if (buildtype)
     set(build_type_flags "-DCMAKE_BUILD_TYPE=${buildtype}")
@@ -32,8 +38,6 @@ function(llvm_create_cross_target_intern
 
   add_custom_command(OUTPUT ${LLVM_${target_name}_BUILD}/CMakeCache.txt
     COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}"
-        -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
-        -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
         ${CROSS_TOOLCHAIN_FLAGS_${target_name}} ${CMAKE_SOURCE_DIR}
         -DLLVM_TARGET_IS_CROSSCOMPILE_HOST=TRUE
         -DLLVM_TARGETS_TO_BUILD=Native