[CMake] Replace the sanitizer support in runtimes build with multilib

[phosek]

Summary

This is a more generic solution; while the sanitizer support can be used
only for sanitizer instrumented builds, the multilib support can be used
to build other variants such as noexcept which is what we would like to use
in Fuchsia.

The name CMake target name uses the target name, same as for the regular
runtimes build and the name of the multilib, concatenated with '+'. The
libraries are installed in a subdirectory named after the multilib.

[phosek]

Ping?

[beanz]

I really like this. Using + to add variants seems much widely useful.

cfe/trunk/cmake/caches/Fuchsia-stage2.cmake

foreach(target x86_64;aarch64)
     set(RUNTIMES_${target}-fuchsia_LIBCXXABI_INSTALL_STATIC_LIBRARY OFF CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_SHARED_LIBRARY OFF CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_LIBCXX_USE_COMPILER_RT ON CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_LIBCXX_HERMETIC_STATIC_LIBRARY ON CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY OFF CACHE BOOL "")
     set(RUNTIMES_${target}-fuchsia_LIBCXX_ABI_VERSION 2 CACHE STRING "")
 
+    set(RUNTIMES_${target}-fuchsia+asan_LLVM_BUILD_COMPILER_RT OFF CACHE BOOL "")
+    set(RUNTIMES_${target}-fuchsia+asan_LLVM_USE_SANITIZER "Address" CACHE STRING "")
+    set(RUNTIMES_${target}-fuchsia+asan_LIBCXXABI_ENABLE_NEW_DELETE_DEFINITIONS OFF CACHE BOOL "")
+    set(RUNTIMES_${target}-fuchsia+asan_LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS OFF CACHE BOOL "")
+
+    set(RUNTIMES_${target}-fuchsia+noexcept_LLVM_BUILD_COMPILER_RT OFF CACHE BOOL "")
+    set(RUNTIMES_${target}-fuchsia+noexcept_LIBCXXABI_ENABLE_EXCEPTIONS OFF CACHE BOOL "")
+    set(RUNTIMES_${target}-fuchsia+noexcept_LIBCXX_ENABLE_EXCEPTIONS OFF CACHE BOOL "")
+
     # Use .build-id link.
     list(APPEND RUNTIME_BUILD_ID_LINK "${target}-fuchsia")
   endforeach()
 
-  set(LLVM_RUNTIME_SANITIZERS "Address" CACHE STRING "")
-  set(LLVM_RUNTIME_SANITIZER_Address_TARGETS "x86_64-fuchsia;aarch64-fuchsia" CACHE STRING "")
+  set(LLVM_RUNTIME_MULTILIBS "asan;noexcept" CACHE STRING "")
+  set(LLVM_RUNTIME_MULTILIB_asan_TARGETS "x86_64-fuchsia;aarch64-fuchsia" CACHE STRING "")
+  set(LLVM_RUNTIME_MULTILIB_noexcept_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 "")
 set(LLVM_RUNTIME_BUILD_ID_LINK_TARGETS "${RUNTIME_BUILD_ID_LINK}" CACHE STRING "")
 
 # Setup toolchain.
 set(LLVM_INSTALL_TOOLCHAIN_ONLY ON CACHE BOOL "")

llvm/trunk/runtimes/CMakeLists.txt

if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
 
   # Some of the runtimes will conditionally use the compiler-rt sanitizers
   # to make this work smoothly we ensure that compiler-rt is added first in
   # the list of sub-projects. This allows other sub-projects to have checks
   # like `if(TARGET asan)` to enable building with asan.
   get_compiler_rt_path(compiler_rt_path)
   if(compiler_rt_path)
     list(REMOVE_ITEM runtimes ${compiler_rt_path})
-    if(NOT LLVM_BUILD_COMPILER_RT)
+    if(NOT DEFINED LLVM_BUILD_COMPILER_RT OR LLVM_BUILD_COMPILER_RT)
       list(INSERT runtimes 0 ${compiler_rt_path})
     endif()
   endif()
 
   # LLVMConfig.cmake contains a bunch of CMake variables from the LLVM build.
   # This file is installed as part of LLVM distributions, so this can be used
   # either from a build directory or an installed LLVM.
   include(LLVMConfig)
foreach(item ${builtin_target_list})
       string(TOLOWER "${item}" item_lower)
       if(item_lower MATCHES "darwin")
         message(FATAL_ERROR "LLVM_BUILTIN_TARGETS isn't implemented for Darwin platform!")
       endif()
     endforeach()
 
     get_cmake_property(variableNames VARIABLES)
     foreach(variableName ${variableNames})
-      if(variableName MATCHES "^BUILTINS_${target}")
+      string(FIND "${variableName}" "BUILTINS_${target}" out)
+      if("${out}" EQUAL 0)
         string(REPLACE "BUILTINS_${target}_" "" new_name ${variableName})
         list(APPEND ${target}_extra_args "-D${new_name}=${${variableName}}")
       endif()
     endforeach()
 
     llvm_ExternalProject_Add(builtins-${target}
                              ${compiler_rt_path}/lib/builtins
                              DEPENDS ${ARG_DEPENDS}
if(LLVM_INCLUDE_TESTS)
         list(APPEND ${name}_test_targets ${target_name}-${name})
         list(APPEND test_targets ${target_name}-${name})
       endforeach()
       set(test_targets "${test_targets}" PARENT_SCOPE)
     endif()
 
     get_cmake_property(variableNames VARIABLES)
     foreach(variableName ${variableNames})
-      if(variableName MATCHES "^RUNTIMES_${name}")
+      string(FIND "${variableName}" "RUNTIMES_${name}_" out)
+      if("${out}" EQUAL 0)
         string(REPLACE "RUNTIMES_${name}_" "" new_name ${variableName})
         list(APPEND ${name}_extra_args "-D${new_name}=${${variableName}}")
-      elseif(variableName MATCHES "^RUNTIMES_${target}")
+      endif()
+      string(FIND "${variableName}" "RUNTIMES_${target}_" out)
+      if("${out}" EQUAL 0)
         string(REPLACE "RUNTIMES_${target}_" "" new_name ${variableName})
         list(APPEND ${name}_extra_args "-D${new_name}=${${variableName}}")
       endif()
     endforeach()
 
     if(target IN_LIST LLVM_RUNTIME_BUILD_ID_LINK_TARGETS)
       list(APPEND EXTRA_ARGS STRIP_TOOL ${CMAKE_CURRENT_BINARY_DIR}/llvm-strip-link)
     endif()
else()
         add_dependencies(install-runtimes install-runtimes-${name})
         add_dependencies(install-runtimes-stripped install-runtimes-${name}-stripped)
         if(LLVM_INCLUDE_TESTS)
           add_dependencies(check-runtimes check-runtimes-${name})
           add_dependencies(runtimes-test-depends runtimes-test-depends-${name})
         endif()
       endforeach()
 
-      foreach(sanitizer ${LLVM_RUNTIME_SANITIZERS})
-        if (sanitizer STREQUAL "Address")
-          set(sanitizer_name "asan")
-        elseif (sanitizer STREQUAL "Memory")
-          set(sanitizer_name "msan")
-        elseif (sanitizer STREQUAL "Thread")
-          set(sanitizer_name "tsan")
-        elseif (sanitizer STREQUAL "Undefined")
-          set(sanitizer_name "ubsan")
-        else()
-          message(FATAL_ERROR "Unsupported value of LLVM_RUNTIME_TARGET_SANITIZERS: ${sanitizers}")
-        endif()
-        foreach(name ${LLVM_RUNTIME_SANITIZER_${sanitizer}_TARGETS})
-          runtime_register_target(${name}-${sanitizer_name} ${name}
+      foreach(multilib ${LLVM_RUNTIME_MULTILIBS})
+        foreach(name ${LLVM_RUNTIME_MULTILIB_${multilib}_TARGETS})
+          runtime_register_target(${name}+${multilib} ${name}
             DEPENDS runtimes-${name}
-            CMAKE_ARGS -DLLVM_USE_SANITIZER=${sanitizer}
-                       -DLLVM_RUNTIMES_PREFIX=${name}/
-                       -DLLVM_RUNTIMES_LIBDIR_SUFFIX=/${sanitizer_name})
-          add_dependencies(runtimes runtimes-${name}-${sanitizer_name})
-          add_dependencies(runtimes-configure runtimes-${name}-${sanitizer_name}-configure)
-          add_dependencies(install-runtimes install-runtimes-${name}-${sanitizer_name})
-          add_dependencies(install-runtimes-stripped install-runtimes-${name}-${sanitizer_name}-stripped)
+            CMAKE_ARGS -DLLVM_RUNTIMES_PREFIX=${name}/
+                       -DLLVM_RUNTIMES_LIBDIR_SUFFIX=/${multilib})
+          add_dependencies(runtimes runtimes-${name}+${multilib})
+          add_dependencies(runtimes-configure runtimes-${name}+${multilib}-configure)
+          add_dependencies(install-runtimes install-runtimes-${name}+${multilib})
+          add_dependencies(install-runtimes-stripped install-runtimes-${name}+${multilib}-stripped)
         endforeach()
       endforeach()
     endif()
 
     # TODO: This is a hack needed because the libcxx headers are copied into the
     # build directory during configuration. Without that step the clang in the
     # build directory cannot find the C++ headers in certain configurations.
     # I need to build a mechanism for runtime projects to provide CMake code