cmake: ccache refactorings

add support for customize cache directory and cache size,
add ccache support for LLVM

CMakeLists.txt

@@ -69,12 +69,19 @@ set(LLVM_ENABLE_LTO "OFF" CACHE STRING "OFF, ON, Thin and Full")
 option(CLANG_PACKAGES_LTO "Build each package with ThinLTO." OFF)
 option(ENABLE_CCACHE "Enable ccache" OFF)
 if(ENABLE_CCACHE)
+    set(CCACHE_MAXSIZE "500M" CACHE STRING "Size of ccache")
+    set(CCACHE_DIR "${MINGW_INSTALL_PREFIX}/ccache" CACHE STRING "Directory to keep ccached data")
     find_program(CCACHE_EXISTS ccache NO_CACHE)
     configure_file(${CMAKE_CURRENT_SOURCE_DIR}/ccache_conf.in ${MINGW_INSTALL_PREFIX}/ccache/ccache.conf @ONLY)
     if(NOT CCACHE_EXISTS)
         set(ENABLE_CCACHE OFF)
     endif()
 endif()
+option(LLVM_CCACHE_BUILD "Enable ccache" OFF)
+if(LLVM_CCACHE_BUILD)
+    set(LLVM_CCACHE_MAXSIZE "500M" CACHE STRING "Size of ccache")
+    set(LLVM_CCACHE_DIR "${CMAKE_INSTALL_PREFIX}/llvm-ccache" CACHE STRING "Directory to keep ccached data")
+endif()
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/toolchain.cmake.in ${CMAKE_CURRENT_BINARY_DIR}/toolchain.cmake @ONLY)
 set(TOOLCHAIN_FILE ${CMAKE_CURRENT_BINARY_DIR}/toolchain.cmake)
 set(CLANG_FLAGS "" CACHE STRING "These flags will be added to the end of the clang args")

ccache_conf.in

@@ -1,4 +1,4 @@
-cache_dir = "@MINGW_INSTALL_PREFIX@/ccache"
-max_size = 500M
+cache_dir = "@CCACHE_DIR@"
+max_size = @CCACHE_MAXSIZE@
 sloppiness = locale,time_macros
 compiler_check = none

cmake/toolchain_check.cmake

@@ -8,6 +8,9 @@ elseif(COMPILER_TOOLCHAIN STREQUAL "clang")
     set(llvm_libcxx "llvm-libcxx")
     set(cfguard "--enable-cfguard")
     set(opt "-O3")
+    if(LLVM_ENABLE_CCACHE)
+        set(llvm_ccache "-DLLVM_CCACHE_BUILD=ON -DLLVM_CCACHE_DIR=${LLVM_CCACHE_DIR} -DLLVM_CCACHE_MAXSIZE=${LLVM_CCACHE_MAXSIZE}")
+    endif()
 endif()
 
 if(TARGET_CPU STREQUAL "x86_64")

toolchain/llvm/llvm.cmake

@@ -14,6 +14,7 @@ ExternalProject_Add(llvm
         -DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
         -DCMAKE_C_COMPILER=clang
         -DCMAKE_CXX_COMPILER=clang++
+        ${llvm_ccache}
         -DCMAKE_BUILD_WITH_INSTALL_RPATH=ON
         -DLLVM_INSTALL_TOOLCHAIN_ONLY=ON
         -DLLVM_TARGETS_TO_BUILD='X86,NVPTX'