From: Joseph Tremoulet <jotrem@microsoft.com>
Date: Wed, 9 Sep 2015 14:57:06 +0000 (+0000)
Subject: [CMake] Flag recursive cmake invocations for cross-compile
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=22c3d9db50721e183294287f2edafc1f4b2c1034;ds=sidebyside

[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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247151 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3518a68ac52..dac209765a8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -560,6 +560,10 @@ include_directories( ${LLVM_INCLUDE_DIR} ${LLVM_MAIN_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
diff --git a/cmake/modules/CrossCompile.cmake b/cmake/modules/CrossCompile.cmake
index 76a3078a544..c136dfaa612 100644
--- a/cmake/modules/CrossCompile.cmake
+++ b/cmake/modules/CrossCompile.cmake
@@ -19,6 +19,7 @@ function(llvm_create_cross_target_internal target_name toochain buildtype)
   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_internal target_name toochain buildtype)
     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})