commit 65c1efb33bf3d84665fe600c2c7c69b54c9deb47
author Louis Dionne <ldionne.2@gmail.com> Tue Oct 12 15:59:08 2021 -0400
committer Copybara-Service <copybara-worker@google.com> Thu Oct 21 07:11:17 2021 -0700
tree 9245c3c5227739f5fc281493fbd25964c0cd4375
parent 559def586c8967e2ceff860dcf55709266f5b566

[runtimes] Properly handle the sysroot/triple/gcc-toolchain

In 395271a, I simplified how we handled the target triple for the
runtimes. However, in doing so, we stopped considering the default
in CMAKE_CXX_COMPILER_TARGET, so we'd use the LLVM_DEFAULT_TARGET_TRIPLE
(which is the host triple) even if CMAKE_CXX_COMPILER_TARGET was specified.
This commit fixes that problem and also refactors the code so that it's
easy to see what the default value is.

The fact that nobody seems to have been broken by this makes me think
that perhaps nobody is using CMAKE_CXX_COMPILER_TARGET to specify the
triple -- but it should still work.

Differential Revision: https://reviews.llvm.org/D111672

GitOrigin-RevId: 72117f2ffeb6a096a808c34ec7ebee122c2d2e21

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index cc1c395..027dafd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -113,9 +113,16 @@
 set(LIBCXXABI_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}" CACHE STRING
     "Define suffix of library directory name (32/64)")
 option(LIBCXXABI_INSTALL_LIBRARY "Install the libc++abi library." ON)
-set(LIBCXXABI_TARGET_TRIPLE "${LLVM_DEFAULT_TARGET_TRIPLE}" CACHE STRING "Target triple for cross compiling.")
-set(LIBCXXABI_GCC_TOOLCHAIN "" CACHE PATH "GCC toolchain for cross compiling.")
-set(LIBCXXABI_SYSROOT "" CACHE PATH "Sysroot for cross compiling.")
+
+if(CMAKE_CXX_COMPILER_TARGET)
+  set(LIBCXXABI_DEFAULT_TARGET_TRIPLE "${CMAKE_CXX_COMPILER_TARGET}")
+else()
+  set(LIBCXXABI_DEFAULT_TARGET_TRIPLE "${LLVM_DEFAULT_TARGET_TRIPLE}")
+endif()
+set(LIBCXXABI_TARGET_TRIPLE "${LIBCXXABI_DEFAULT_TARGET_TRIPLE}" CACHE STRING "Target triple for cross compiling.")
+set(LIBCXXABI_GCC_TOOLCHAIN "${CMAKE_CXX_COMPILER_EXTERNAL_TOOLCHAIN}" CACHE PATH "GCC toolchain for cross compiling.")
+set(LIBCXXABI_SYSROOT "${CMAKE_SYSROOT}" CACHE PATH "Sysroot for cross compiling.")
+
 set(LIBCXXABI_LIBCXX_LIBRARY_PATH "" CACHE PATH "The path to libc++ library.")
 set(LIBCXXABI_LIBRARY_VERSION "1.0" CACHE STRING
 "Version of libc++abi. This will be reflected in the name of the shared \
@@ -271,18 +278,12 @@
 
 if(LIBCXXABI_TARGET_TRIPLE)
   add_target_flags_if_supported("--target=${LIBCXXABI_TARGET_TRIPLE}")
-elseif(CMAKE_CXX_COMPILER_TARGET)
-  set(LIBCXXABI_TARGET_TRIPLE "${CMAKE_CXX_COMPILER_TARGET}")
 endif()
-if(LIBCXX_GCC_TOOLCHAIN)
+if(LIBCXXABI_GCC_TOOLCHAIN)
   add_target_flags_if_supported("--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_if_supported("--sysroot=${LIBCXXABI_SYSROOT}")
-elseif(CMAKE_SYSROOT)
-  set(LIBCXXABI_SYSROOT "${CMAKE_SYSROOT}")
 endif()
 
 # Configure compiler. Must happen after setting the target flags.