[CMake] Use explicit targets for building Linux runtimes

[phosek]

Summary

Previously we were using default logic when building Linux runtimes
in Fuchsia toolchain, but that leads to various issues due to how
the CMake logic in compiler-rt for determining the platform support
is implemented. With this change, we will use explicit target for
every provided Linux sysroot.

[mcgrathr]

lgtm

cmake/caches/Fuchsia-stage2.cmake

 # This file sets up a CMakeCache for the second stage of a Fuchsia toolchain
 # build.
 
 set(LLVM_TARGETS_TO_BUILD X86;ARM;AArch64 CACHE STRING "")
 
 set(PACKAGE_VENDOR Fuchsia CACHE STRING "")
 
 set(LLVM_INCLUDE_EXAMPLES OFF CACHE BOOL "")
 set(LLVM_INCLUDE_DOCS OFF CACHE BOOL "")
 set(LLVM_ENABLE_BACKTRACES OFF CACHE BOOL "")
+set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR ON CACHE BOOL "")
 set(LLVM_ENABLE_TERMINFO OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB ON CACHE BOOL "")
 set(LLVM_EXTERNALIZE_DEBUGINFO ON CACHE BOOL "")
 set(CLANG_PLUGIN_SUPPORT OFF CACHE BOOL "")
 
 set(LLVM_ENABLE_LTO ON CACHE BOOL "")
 if(NOT APPLE)
   set(LLVM_ENABLE_LLD ON CACHE BOOL "")
   set(CLANG_DEFAULT_LINKER lld CACHE STRING "")
   set(CLANG_DEFAULT_OBJCOPY llvm-objcopy CACHE STRING "")
 endif()
 set(CLANG_DEFAULT_CXX_STDLIB libc++ CACHE STRING "")
 set(CLANG_DEFAULT_RTLIB compiler-rt CACHE STRING "")
 
 set(LLVM_ENABLE_ASSERTIONS ON CACHE BOOL "")
 set(CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
 set(CMAKE_C_FLAGS_RELWITHDEBINFO "-O3 -gline-tables-only -DNDEBUG" CACHE STRING "")
 set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O3 -gline-tables-only -DNDEBUG" CACHE STRING "")
 
-set(FUCHSIA_BUILTINS_BUILD_TYPE Release CACHE STRING "")
-set(FUCHSIA_RUNTIMES_BUILD_TYPE Release CACHE STRING "")
-set(FUCHSIA_RUNTIMES_ENABLE_ASSERTIONS ON CACHE BOOL "")
+if(APPLE)
+  list(APPEND BUILTIN_TARGETS "default")
+  list(APPEND RUNTIME_TARGETS "default")
+endif()
+
+foreach(target i386;x86_64;armhf;aarch64)
+  if(LINUX_${target}_SYSROOT)
+    # Set the per-target builtins options.
+    list(APPEND BUILTIN_TARGETS "${target}-linux-gnu")
+    set(BUILTINS_${target}-linux-gnu_CMAKE_SYSTEM_NAME Linux CACHE STRING "")
+    set(BUILTINS_${target}-linux-gnu_CMAKE_BUILD_TYPE Release CACHE STRING "")
+    set(BUILTINS_${target}-linux-gnu_CMAKE_SYSROOT ${LINUX_${target}_SYSROOT} CACHE STRING "")
+
+    # Set the per-target runtimes options.
+    list(APPEND RUNTIME_TARGETS "${target}-linux-gnu")
+    set(RUNTIMES_${target}-linux-gnu_CMAKE_SYSTEM_NAME Linux CACHE STRING "")
+    set(RUNTIMES_${target}-linux-gnu_CMAKE_BUILD_TYPE Release CACHE STRING "")
+    set(RUNTIMES_${target}-linux-gnu_CMAKE_SYSROOT ${LINUX_${target}_SYSROOT} CACHE STRING "")
+    set(RUNTIMES_${target}-linux-gnu_LLVM_ENABLE_ASSERTIONS ON CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBUNWIND_ENABLE_SHARED OFF CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBUNWIND_INSTALL_LIBRARY OFF CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBCXXABI_ENABLE_STATIC_UNWINDER ON CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBCXXABI_INSTALL_LIBRARY OFF CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBCXX_USE_COMPILER_RT ON CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBCXX_ENABLE_SHARED OFF CACHE BOOL "")
+    set(RUNTIMES_${target}-linux-gnu_LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")
+  endif()
+endforeach()
 
+if(FUCHSIA_SDK)
   set(FUCHSIA_aarch64_NAME arm64)
   set(FUCHSIA_x86_64_NAME x64)
   foreach(target x86_64;aarch64)
     set(FUCHSIA_${target}_COMPILER_FLAGS "-I${FUCHSIA_SDK}/pkg/fdio/include")
     set(FUCHSIA_${target}_LINKER_FLAGS "-L${FUCHSIA_SDK}/arch/${FUCHSIA_${target}_NAME}/lib")
     set(FUCHSIA_${target}_SYSROOT "${FUCHSIA_SDK}/arch/${FUCHSIA_${target}_NAME}/sysroot")
   endforeach()
 
-set(LLVM_BUILTIN_TARGETS "default;x86_64-fuchsia;aarch64-fuchsia" CACHE STRING "")
-
-# Set the per-target builtins options.
   foreach(target x86_64;aarch64)
+    # Set the per-target builtins options.
+    list(APPEND BUILTIN_TARGETS "${target}-fuchsia")
     set(BUILTINS_${target}-fuchsia_CMAKE_SYSTEM_NAME Fuchsia CACHE STRING "")
-  set(BUILTINS_${target}-fuchsia_CMAKE_BUILD_TYPE ${FUCHSIA_BUILTINS_BUILD_TYPE} CACHE STRING "")
+    set(BUILTINS_${target}-fuchsia_CMAKE_BUILD_TYPE Release CACHE STRING "")
     set(BUILTINS_${target}-fuchsia_CMAKE_ASM_FLAGS ${FUCHSIA_${target}_COMPILER_FLAGS} CACHE PATH "")
     set(BUILTINS_${target}-fuchsia_CMAKE_C_FLAGS ${FUCHSIA_${target}_COMPILER_FLAGS} CACHE PATH "")
     set(BUILTINS_${target}-fuchsia_CMAKE_CXX_FLAGS ${FUCHSIA_${target}_COMPILER_FLAGS} CACHE PATH "")
     set(BUILTINS_${target}-fuchsia_CMAKE_SHARED_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
     set(BUILTINS_${target}-fuchsia_CMAKE_MODULE_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
     set(BUILTINS_${target}-fuchsia_CMAKE_EXE_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
     set(BUILTINS_${target}-fuchsia_CMAKE_SYSROOT ${FUCHSIA_${target}_SYSROOT} CACHE PATH "")
-endforeach()
-
-set(LLVM_RUNTIME_TARGETS "default;x86_64-fuchsia;aarch64-fuchsia" CACHE STRING "")
-set(LLVM_RUNTIME_SANITIZERS "Address" CACHE STRING "")
-set(LLVM_RUNTIME_SANITIZER_Address_TARGETS "x86_64-fuchsia;aarch64-fuchsia" CACHE STRING "")
-
-# Set the default target runtimes options.
-if(NOT APPLE)
-  set(LIBUNWIND_ENABLE_SHARED OFF CACHE BOOL "")
-  set(LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
-  set(LIBUNWIND_INSTALL_LIBRARY OFF CACHE BOOL "")
-  set(LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")
-  set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
-  set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
-  set(LIBCXXABI_ENABLE_STATIC_UNWINDER ON CACHE BOOL "")
-  set(LIBCXXABI_INSTALL_LIBRARY OFF CACHE BOOL "")
-  set(LIBCXX_USE_COMPILER_RT ON CACHE BOOL "")
-  set(LIBCXX_ENABLE_SHARED OFF CACHE BOOL "")
-  set(LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")
-endif()
 
     # Set the per-target runtimes options.
-foreach(target x86_64;aarch64)
+    list(APPEND RUNTIME_TARGETS "${target}-fuchsia")
     set(RUNTIMES_${target}-fuchsia_CMAKE_SYSTEM_NAME Fuchsia CACHE STRING "")
-  set(RUNTIMES_${target}-fuchsia_CMAKE_BUILD_TYPE ${FUCHSIA_RUNTIMES_BUILD_TYPE} CACHE STRING "")
+    set(RUNTIMES_${target}-fuchsia_CMAKE_BUILD_TYPE Release CACHE STRING "")
     set(RUNTIMES_${target}-fuchsia_CMAKE_BUILD_WITH_INSTALL_RPATH ON CACHE STRING "")
     set(RUNTIMES_${target}-fuchsia_CMAKE_ASM_FLAGS ${FUCHSIA_${target}_COMPILER_FLAGS} CACHE PATH "")
     set(RUNTIMES_${target}-fuchsia_CMAKE_C_FLAGS ${FUCHSIA_${target}_COMPILER_FLAGS} CACHE PATH "")
     set(RUNTIMES_${target}-fuchsia_CMAKE_CXX_FLAGS ${FUCHSIA_${target}_COMPILER_FLAGS} CACHE PATH "")
     set(RUNTIMES_${target}-fuchsia_CMAKE_SHARED_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
     set(RUNTIMES_${target}-fuchsia_CMAKE_MODULE_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
     set(RUNTIMES_${target}-fuchsia_CMAKE_EXE_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
     set(RUNTIMES_${target}-fuchsia_CMAKE_SYSROOT ${FUCHSIA_${target}_SYSROOT} CACHE PATH "")
-  set(RUNTIMES_${target}-fuchsia_LLVM_ENABLE_ASSERTIONS ${FUCHSIA_RUNTIMES_ENABLE_ASSERTIONS} CACHE BOOL "")
+    set(RUNTIMES_${target}-fuchsia_LLVM_ENABLE_ASSERTIONS ON CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_LIBCXX_USE_COMPILER_RT ON CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_SANITIZER_USE_COMPILER_RT ON CACHE BOOL "")
   endforeach()
 
+  set(LLVM_RUNTIME_SANITIZERS "Address" CACHE STRING "")
+  set(LLVM_RUNTIME_SANITIZER_Address_TARGETS "x86_64-fuchsia;aarch64-fuchsia" CACHE STRING "")
+endif()
+
+set(LLVM_BUILTIN_TARGETS "${BUILTIN_TARGETS}" CACHE STRING "")
+set(LLVM_RUNTIME_TARGETS "${RUNTIME_TARGETS}" CACHE STRING "")
+
 # Setup toolchain.
 set(LLVM_INSTALL_TOOLCHAIN_ONLY ON CACHE BOOL "")
 set(LLVM_TOOLCHAIN_TOOLS
   dsymutil
   llc
   llvm-ar
   llvm-cov
   llvm-cxxfilt

cmake/caches/Fuchsia.cmake

 # This file sets up a CMakeCache for a Fuchsia toolchain build.
 
 set(LLVM_TARGETS_TO_BUILD Native CACHE STRING "")
 
 set(PACKAGE_VENDOR Fuchsia CACHE STRING "")
 
 set(LLVM_INCLUDE_EXAMPLES OFF CACHE BOOL "")
 set(LLVM_INCLUDE_TESTS OFF CACHE BOOL "")
 set(LLVM_INCLUDE_DOCS OFF CACHE BOOL "")
-set(CLANG_INCLUDE_TESTS OFF CACHE BOOL "")
 set(LLVM_ENABLE_BACKTRACES OFF CACHE BOOL "")
+set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR ON CACHE BOOL "")
 set(LLVM_ENABLE_TERMINFO OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB OFF CACHE BOOL "")
+set(CLANG_INCLUDE_TESTS OFF CACHE BOOL "")
 set(CLANG_PLUGIN_SUPPORT OFF CACHE BOOL "")
 
 set(LLVM_ENABLE_ASSERTIONS ON CACHE BOOL "")
 set(CMAKE_BUILD_TYPE Release CACHE STRING "")
 
 set(BOOTSTRAP_LLVM_ENABLE_LTO ON CACHE BOOL "")
 if(NOT APPLE)
   set(BOOTSTRAP_LLVM_ENABLE_LLD ON CACHE BOOL "")