[CMake] Support CMake variables for setting target, sysroot and toolchain

CMake has a standard way of setting target triple, sysroot and external
toolchain through CMAKE_<LANG>_COMPILER_TARGET, CMAKE_SYSROOT and
CMAKE_<LANG>_COMPILER_EXTERNAL_TOOLCHAIN. These are turned into
corresponding --target=, --sysroot= and --gcc-toolchain= variables add
included appended to CMAKE_<LANG>_FLAGS.

libunwind, libc++abi, libc++ provides their own mechanism through
<PROJECT>_TARGET_TRIPLE, <PROJECT>_SYSROOT and <PROJECT>_GCC_TOOLCHAIN
variables. These are also passed to lit via lit.site.cfg, and lit config
uses these to set the corresponding compiler flags when building tessts.

This means that there are two different ways of setting target, sysroot
and toolchain, but only one is properly supported in lit. This change
extends CMake build for libunwind, libc++abi and libc++ to also support
the CMake variables in addition to project specific ones in lit.

Differential Revision: https://reviews.llvm.org/D57670

llvm-svn: 353084

6 files changed, 54 insertions, 19 deletions

diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index 9e27ba41e99..c6b05b61f6a 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -224,6 +224,7 @@ option(LIBCXXABI_ENABLE_STATIC_UNWINDER "Statically link the LLVM unwinder." OFF
 
 # Target options --------------------------------------------------------------
 option(LIBCXX_BUILD_32_BITS "Build 32 bit libc++." ${LLVM_BUILD_32_BITS})
+set(LIBCXX_TARGET_TRIPLE "" CACHE STRING "Use alternate target triple.")
 set(LIBCXX_SYSROOT "" CACHE STRING "Use alternate sysroot.")
 set(LIBCXX_GCC_TOOLCHAIN "" CACHE STRING "Use alternate GCC toolchain.")
 
@@ -460,10 +461,24 @@ include(HandleLibcxxFlags)
 # 'config-ix' use them during feature checks. It also adds them to both
 # 'LIBCXX_COMPILE_FLAGS' and 'LIBCXX_LINK_FLAGS'
 add_target_flags_if(LIBCXX_BUILD_32_BITS "-m32")
-add_target_flags_if(LIBCXX_TARGET_TRIPLE "--target=${LIBCXX_TARGET_TRIPLE}")
-add_target_flags_if(LIBCXX_SYSROOT "--sysroot=${LIBCXX_SYSROOT}")
-add_target_flags_if(LIBCXX_GCC_TOOLCHAIN "--gcc-toolchain=${LIBCXX_GCC_TOOLCHAIN}")
-if (LIBCXX_TARGET_TRIPLE)
+
+if(LIBCXX_TARGET_TRIPLE)
+  add_target_flags("--target=${LIBCXX_TARGET_TRIPLE}")
+elseif(CMAKE_CXX_COMPILER_TARGET)
+  set(LIBCXX_TARGET_TRIPLE "${CMAKE_CXX_COMPILER_TARGET}")
+endif()
+if(LIBCXX_SYSROOT)
+  add_target_flags("--sysroot=${LIBCXX_SYSROOT}")
+elseif(CMAKE_SYSROOT)
+  set(LIBCXX_SYSROOT "${CMAKE_SYSROOT}")
+endif()
+if(LIBCXX_GCC_TOOLCHAIN)
+  add_target_flags("--gcc-toolchain=${LIBCXX_GCC_TOOLCHAIN}")
+elseif(CMAKE_CXX_COMPILER_EXTERNAL_TOOLCHAIN)
+  set(LIBCXX_GCC_TOOLCHAIN "${CMAKE_CXX_COMPILER_EXTERNAL_TOOLCHAIN}")
+endif()
+
+if(LIBCXX_TARGET_TRIPLE)
   set(TARGET_TRIPLE "${LIBCXX_TARGET_TRIPLE}")
 endif()
 
diff --git a/libcxx/test/lit.site.cfg.in b/libcxx/test/lit.site.cfg.in
index 53f797268f1..cb7b62c9a4f 100644
--- a/libcxx/test/lit.site.cfg.in
+++ b/libcxx/test/lit.site.cfg.in
@@ -17,7 +17,7 @@ config.abi_library_path         = "@LIBCXX_CXX_ABI_LIBRARY_PATH@"
 config.configuration_variant    = "@LIBCXX_LIT_VARIANT@"
 config.host_triple              = "@LLVM_HOST_TRIPLE@"
 config.target_triple            = "@TARGET_TRIPLE@"
-config.use_target               = len("@LIBCXX_TARGET_TRIPLE@") > 0
+config.use_target               = bool("@LIBCXX_TARGET_TRIPLE@")
 config.sysroot                  = "@LIBCXX_SYSROOT@"
 config.gcc_toolchain            = "@LIBCXX_GCC_TOOLCHAIN@"
 config.generate_coverage        = "@LIBCXX_GENERATE_COVERAGE@"
diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
index 664e1fed034..b5b29e7498f 100644
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -231,12 +231,22 @@ include(HandleLibcxxabiFlags)
 
 # Configure target flags
 add_target_flags_if(LIBCXXABI_BUILD_32_BITS "-m32")
-add_target_flags_if(LIBCXXABI_TARGET_TRIPLE
-          "--target=${LIBCXXABI_TARGET_TRIPLE}")
-add_target_flags_if(LIBCXXABI_GCC_TOOLCHAIN
-         "--gcc-toolchain=${LIBCXXABI_GCC_TOOLCHAIN}")
-add_target_flags_if(LIBCXXABI_SYSROOT
-          "--sysroot=${LIBCXXABI_SYSROOT}")
+
+if(LIBCXXABI_TARGET_TRIPLE)
+  add_target_flags("--target=${LIBCXXABI_TARGET_TRIPLE}")
+elseif(CMAKE_CXX_COMPILER_TARGET)
+  set(LIBCXXABI_TARGET_TRIPLE "${CMAKE_CXX_COMPILER_TARGET}")
+endif()
+if(LIBCXX_GCC_TOOLCHAIN)
+  add_target_flags("--gcc-toolchain=${LIBCXXABI_GCC_TOOLCHAIN}")
+elseif(CMAKE_CXX_COMPILER_EXTERNAL_TOOLCHAIN)
+  set(LIBCXXABI_GCC_TOOLCHAIN "${CMAKE_CXX_COMPILER_EXTERNAL_TOOLCHAIN}")
+endif()
+if(LIBCXXABI_SYSROOT)
+  add_target_flags("--sysroot=${LIBCXXABI_SYSROOT}")
+elseif(CMAKE_SYSROOT)
+  set(LIBCXXABI_SYSROOT "${CMAKE_SYSROOT}")
+endif()
 
 if (LIBCXXABI_TARGET_TRIPLE)
   set(TARGET_TRIPLE "${LIBCXXABI_TARGET_TRIPLE}")
diff --git a/libcxxabi/test/lit.site.cfg.in b/libcxxabi/test/lit.site.cfg.in
index 75cb76e2557..d8e58be1bb2 100644
--- a/libcxxabi/test/lit.site.cfg.in
+++ b/libcxxabi/test/lit.site.cfg.in
@@ -20,7 +20,7 @@ config.enable_shared            = "@LIBCXX_ENABLE_SHARED@"
 config.enable_exceptions        = "@LIBCXXABI_ENABLE_EXCEPTIONS@"
 config.host_triple              = "@LLVM_HOST_TRIPLE@"
 config.target_triple            = "@TARGET_TRIPLE@"
-config.use_target               = len("@LIBCXXABI_TARGET_TRIPLE@") > 0
+config.use_target               = bool("@LIBCXXABI_TARGET_TRIPLE@")
 config.sysroot                  = "@LIBCXXABI_SYSROOT@"
 config.gcc_toolchain            = "@LIBCXXABI_GCC_TOOLCHAIN@"
 config.cxx_ext_threads          = "@LIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY@"
diff --git a/libunwind/CMakeLists.txt b/libunwind/CMakeLists.txt
index 41b990f81c4..3206c150645 100644
--- a/libunwind/CMakeLists.txt
+++ b/libunwind/CMakeLists.txt
@@ -225,12 +225,22 @@ macro(add_target_flags_if condition var)
 endmacro()
 
 add_target_flags_if(LIBUNWIND_BUILD_32_BITS "-m32")
-add_target_flags_if(LIBUNWIND_TARGET_TRIPLE
-          "--target=${LIBUNWIND_TARGET_TRIPLE}")
-add_target_flags_if(LIBUNWIND_GCC_TOOLCHAIN
-          "--gcc-toolchain=${LIBUNWIND_GCC_TOOLCHAIN}")
-add_target_flags_if(LIBUNWIND_SYSROOT
-          "--sysroot=${LIBUNWIND_SYSROOT}")
+
+if(LIBUNWIND_TARGET_TRIPLE)
+  add_target_flags("--target=${LIBUNWIND_TARGET_TRIPLE}")
+elseif(CMAKE_CXX_COMPILER_TARGET)
+  set(LIBUNWIND_TARGET_TRIPLE "${CMAKE_CXX_COMPILER_TARGET}")
+endif()
+if(LIBUNWIND_GCC_TOOLCHAIN)
+  add_target_flags("--gcc-toolchain=${LIBUNWIND_GCC_TOOLCHAIN}")
+elseif(CMAKE_CXX_COMPILER_EXTERNAL_TOOLCHAIN)
+  set(LIBUNWIND_GCC_TOOLCHAIN "${CMAKE_CXX_COMPILER_EXTERNAL_TOOLCHAIN}")
+endif()
+if(LIBUNWIND_SYSROOT)
+  add_target_flags("--sysroot=${LIBUNWIND_SYSROOT}")
+elseif(CMAKE_SYSROOT)
+  set(LIBUNWIND_SYSROOT "${CMAKE_SYSROOT}")
+endif()
 
 if (LIBUNWIND_TARGET_TRIPLE)
   set(TARGET_TRIPLE "${LIBUNWIND_TARGET_TRIPLE}")
diff --git a/libunwind/test/lit.site.cfg.in b/libunwind/test/lit.site.cfg.in
index 8e3bb72e0a4..2532a3e0545 100644
--- a/libunwind/test/lit.site.cfg.in
+++ b/libunwind/test/lit.site.cfg.in
@@ -20,7 +20,7 @@ config.enable_shared            = "@LIBCXX_ENABLE_SHARED@"
 config.enable_exceptions        = "@LIBUNWIND_ENABLE_EXCEPTIONS@"
 config.host_triple              = "@LLVM_HOST_TRIPLE@"
 config.target_triple            = "@TARGET_TRIPLE@"
-config.use_target               = len("@LIBUNWIND_TARGET_TRIPLE@") > 0
+config.use_target               = bool("@LIBUNWIND_TARGET_TRIPLE@")
 config.sysroot                  = "@LIBUNWIND_SYSROOT@"
 config.gcc_toolchain            = "@LIBUNWIND_GCC_TOOLCHAIN@"
 config.cxx_ext_threads          = "@LIBUNWIND_BUILD_EXTERNAL_THREAD_LIBRARY@"