[llvm] r247151 - [CMake] Flag recursive cmake invocations for cross-compile

[Joseph Tremoulet via llvm-commits]

Author: josepht
Date: Wed Sep  9 09:57:06 2015
New Revision: 247151

URL: http://llvm.org/viewvc/llvm-project?rev=247151&view=rev
Log:
[CMake] Flag recursive cmake invocations for cross-compile

Summary:
Cross-compilation uses recursive cmake invocations to build native host
tools.  These recursive invocations only forward a fixed set of
variables/options, since the native environment is generally the default.
This change adds -DLLVM_TARGET_IS_CROSSCOMPILE_HOST=TRUE to the recursive
cmake invocations, so that cmake files can distinguish these recursive
invocations from top-level ones, which can explain why expected options
are unset.

LLILC will use this to avoid trying to generate its build rules in the
crosscompile native host target (where it is not needed), which would fail
if attempted because LLILC requires a cmake variable passed on the command
line, which is not forwarded in the recursive invocation.

Reviewers: rnk, beanz

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12679

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

Modified: llvm/trunk/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/CMakeLists.txt?rev=247151&r1=247150&r2=247151&view=diff
==============================================================================
--- llvm/trunk/CMakeLists.txt (original)
+++ llvm/trunk/CMakeLists.txt Wed Sep  9 09:57:06 2015
@@ -560,6 +560,10 @@ include_directories( ${LLVM_INCLUDE_DIR}
 if(LLVM_USE_HOST_TOOLS)
   include(CrossCompile)
 endif(LLVM_USE_HOST_TOOLS)
+if(LLVM_TARGET_IS_CROSSCOMPILE_HOST)
+# Dummy use to avoid CMake Wraning: Manually-specified variables were not used
+# (this is a variable that CrossCompile sets on recursive invocations)
+endif()
 
 if(${CMAKE_SYSTEM_NAME} MATCHES "(FreeBSD|DragonFly)")
   # On FreeBSD, /usr/local/* is not used by default. In order to build LLVM

Modified: llvm/trunk/cmake/modules/CrossCompile.cmake
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/cmake/modules/CrossCompile.cmake?rev=247151&r1=247150&r2=247151&view=diff
==============================================================================
--- llvm/trunk/cmake/modules/CrossCompile.cmake (original)
+++ llvm/trunk/cmake/modules/CrossCompile.cmake Wed Sep  9 09:57:06 2015
@@ -19,6 +19,7 @@ function(llvm_create_cross_target_intern
   add_custom_command(OUTPUT ${LLVM_${target_name}_BUILD}/CMakeCache.txt
     COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}"
         ${CROSS_TOOLCHAIN_FLAGS_${target_name}} ${CMAKE_SOURCE_DIR}
+        -DLLVM_TARGET_IS_CROSSCOMPILE_HOST=TRUE
     WORKING_DIRECTORY ${LLVM_${target_name}_BUILD}
     DEPENDS ${LLVM_${target_name}_BUILD}
     COMMENT "Configuring ${target_name} LLVM...")
@@ -43,6 +44,7 @@ function(llvm_create_cross_target_intern
     execute_process(COMMAND ${CMAKE_COMMAND} ${build_type_flags}
         -G "${CMAKE_GENERATOR}" -DLLVM_TARGETS_TO_BUILD=${LLVM_TARGETS_TO_BUILD}
         ${CROSS_TOOLCHAIN_FLAGS_${target_name}} ${CMAKE_SOURCE_DIR}
+        -DLLVM_TARGET_IS_CROSSCOMPILE_HOST=TRUE
       WORKING_DIRECTORY ${LLVM_${target_name}_BUILD} )
   endif(NOT IS_DIRECTORY ${LLVM_${target_name}_BUILD})