[Fuzzer] Avoid the unnecessary rebuild of the custom libc++

This changes the add_custom_libcxx macro to resemble the
llvm_ExternalProject_Add. The primary motivation is to avoid
unnecessary libFuzzer rebuilds that are being done on every
Ninja/Make invocation. The libc++ should be only rebuilt whenever
the libc++ source itself changes.

Differential Revision: https://reviews.llvm.org/D43213

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@326921 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 61 insertions, 20 deletions

diff --git a/cmake/Modules/AddCompilerRT.cmake b/cmake/Modules/AddCompilerRT.cmake
index f81eb3342..2383670a9 100644
--- a/cmake/Modules/AddCompilerRT.cmake
+++ b/cmake/Modules/AddCompilerRT.cmake
@@ -477,56 +477,97 @@ macro(add_custom_libcxx name prefix)
   foreach(flag ${LIBCXX_CFLAGS})
     set(flagstr "${flagstr} ${flag}")
   endforeach()
-  set(LIBCXX_CFLAGS ${flagstr})
+  set(LIBCXX_C_FLAGS ${flagstr})
+  set(LIBCXX_CXX_FLAGS ${flagstr})
 
   if(LIBCXX_USE_TOOLCHAIN)
     set(compiler_args -DCMAKE_C_COMPILER=${COMPILER_RT_TEST_COMPILER}
                       -DCMAKE_CXX_COMPILER=${COMPILER_RT_TEST_CXX_COMPILER})
     if(NOT COMPILER_RT_STANDALONE_BUILD)
-      set(force_deps DEPENDS clang)
+      set(toolchain_deps $<TARGET_FILE:clang>)
+      set(force_deps DEPENDS $<TARGET_FILE:clang>)
     endif()
   else()
     set(compiler_args -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
                       -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER})
   endif()
 
+  set(STAMP_DIR ${prefix}-stamps/)
+  set(BINARY_DIR ${prefix}-bins/)
+
+  add_custom_target(${name}-clear
+    COMMAND ${CMAKE_COMMAND} -E remove_directory ${BINARY_DIR}
+    COMMAND ${CMAKE_COMMAND} -E remove_directory ${STAMP_DIR}
+    COMMENT "Clobbering ${name} build and stamp directories"
+    USES_TERMINAL
+    )
+
+  add_custom_command(
+    OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp
+    DEPENDS ${LIBCXX_DEPS} ${toolchain_deps}
+    COMMAND ${CMAKE_COMMAND} -E touch ${BINARY_DIR}/CMakeCache.txt
+    COMMAND ${CMAKE_COMMAND} -E touch ${STAMP_DIR}/${name}-mkdir
+    COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp
+    COMMENT "Clobbering bootstrap build and stamp directories"
+    )
+
+  add_custom_target(${name}-clobber
+    DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp)
+
   if(CMAKE_SYSROOT)
     set(sysroot_arg -DCMAKE_SYSROOT=${CMAKE_SYSROOT})
   endif()
 
   ExternalProject_Add(${name}
-    DEPENDS ${LIBCXX_DEPS}
+    DEPENDS ${name}-clobber ${LIBCXX_DEPS}
     PREFIX ${prefix}
     SOURCE_DIR ${COMPILER_RT_LIBCXX_PATH}
+    STAMP_DIR ${STAMP_DIR}
+    BINARY_DIR ${BINARY_DIR}
     CMAKE_ARGS -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}
                ${compiler_args}
                ${sysroot_arg}
-               -DCMAKE_C_FLAGS=${LIBCXX_CFLAGS}
-               -DCMAKE_CXX_FLAGS=${LIBCXX_CFLAGS}
+               -DCMAKE_C_FLAGS=${LIBCXX_C_FLAGS}
+               -DCMAKE_CXX_FLAGS=${LIBCXX_CXX_FLAGS}
                -DCMAKE_BUILD_TYPE=Release
-               -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
+               -DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
                -DLLVM_PATH=${LLVM_MAIN_SRC_DIR}
-               -DLIBCXX_STANDALONE_BUILD=On
+               -DLLVM_BINARY_DIR=${prefix}
+               -DLLVM_LIBRARY_OUTPUT_INTDIR=${prefix}/lib
+               -DLIBCXX_STANDALONE_BUILD=ON
                ${LIBCXX_CMAKE_ARGS}
-    STEP_TARGETS configure build install
-    LOG_BUILD 1
-    LOG_CONFIGURE 1
-    LOG_INSTALL 1
+    INSTALL_COMMAND ""
+    STEP_TARGETS configure build
+    BUILD_ALWAYS 1
+    USES_TERMINAL_CONFIGURE 1
+    USES_TERMINAL_BUILD 1
+    USES_TERMINAL_INSTALL 1
     EXCLUDE_FROM_ALL TRUE
     )
 
-  ExternalProject_Add_Step(${name} force-reconfigure
-    DEPENDERS configure
-    ALWAYS 1
-    )
+  if (CMAKE_GENERATOR MATCHES "Make")
+    set(run_clean "$(MAKE)" "-C" "${BINARY_DIR}" "clean")
+  else()
+    set(run_clean ${CMAKE_COMMAND} --build ${BINARY_DIR} --target clean
+                                   --config "$<CONFIGURATION>")
+  endif()
 
-  ExternalProject_Add_Step(${name} clobber
-    COMMAND ${CMAKE_COMMAND} -E remove_directory <BINARY_DIR>
-    COMMAND ${CMAKE_COMMAND} -E make_directory <BINARY_DIR>
-    COMMENT "Clobberring ${name} build directory..."
-    DEPENDERS configure
+  ExternalProject_Add_Step(${name} clean
+    COMMAND ${run_clean}
+    COMMENT "Cleaning ${name}..."
+    DEPENDEES configure
     ${force_deps}
+    WORKING_DIRECTORY ${BINARY_DIR}
+    EXCLUDE_FROM_MAIN 1
+    USES_TERMINAL 1
     )
+  ExternalProject_Add_StepTargets(${name} clean)
+
+  if(LIBCXX_USE_TOOLCHAIN)
+    add_dependencies(${name}-clean ${name}-clobber)
+    set_target_properties(${name}-clean PROPERTIES
+      SOURCES ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp)
+  endif()
 endmacro()
 
 function(rt_externalize_debuginfo name)