enable cross compilation with cmake
This patch allows us to use cmake to specify a cross compiler: target different
than host. In particular, it moves LLVM_DEFAULT_TARGET_TRIPLE and TARGET_TRIPLE
variables from cmake/config-ix.cmake to the toplevel CMakeLists.txt to make them
available at configure time.
Here is the command line that I have used to test my patches to create a Hexagon
cross compiler hosted on x86:
$ cmake -G Ninja -D LLVM_TARGETS_TO_BUILD:STRING=Hexagon -D TARGET_TRIPLE:STRING=hexagon-unknown-linux-gnu -D LLVM_DEFAULT_TARGET_TRIPLE:STRING=hexagon-unknown-linux-gnu -D LLVM_TARGET_ARCH:STRING=hexagon-unknown-linux-gnu ..
$ ninja check
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162219 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CMakeLists.txt b/CMakeLists.txt
index fbf8e2b..df781f5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -249,6 +249,14 @@
# BEFORE this include, otherwise options will not be correctly set on
# first cmake run
include(config-ix)
+
+# By default, we target the host, but this can be overridden at CMake
+# invocation time.
+set(LLVM_DEFAULT_TARGET_TRIPLE "${LLVM_HOST_TRIPLE}" CACHE STRING
+ "Default target for which LLVM will generate code." )
+set(TARGET_TRIPLE "${LLVM_DEFAULT_TARGET_TRIPLE}" CACHE STRING
+ "Default target for which LLVM will generate code." )
+
include(HandleLLVMOptions)
# Verify that we can find a Python interpreter,