From: Dan Liew Date: Tue, 5 Feb 2019 08:47:28 +0000 (+0000) Subject: Previously if the user configured their build but then changed X-Git-Tag: llvmorg-10-init~12794 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=de5220ed5e5ab1f7064e9bae57d7b4b8887277fa;p=platform%2Fupstream%2Fllvm.git Previously if the user configured their build but then changed LLVM_ENABLED_PROJECT and reconfigured it had no effect on what projects were actually built. This was very confusing behaviour. The reason for this is that the value of the `LLVM_TOOL__BUILD` variables are already set. The problem here is that we have two sources of truth: * The projects listed in LLVM_ENABLE_PROJECTS. * The projects enabled/disabled with LLVM_TOOL__BUILD. At configure time we have no real way of knowing which source of truth the user wants so we apply the following heuristic: If the user ever sets `LLVM_ENABLE_PROJECTS` in the CMakeCache then that is used as the single source of truth and we force the `LLVM_TOOL__BUILD` CMake cache variables to have the appropriate values that match the contents of the `LLVM_ENABLE_PROJECTS`. If the user never sets `LLVM_ENABLE_PROJECTS` then they can continue to use and set the `LLVM_TOOL__BUILD` variables as the "source of truth". The problem with this approach is that if the user ever tries to use both `LLVM_ENABLE_PROJECTS` and `LLVM_TOOL__BUILD` for the same build directory then any user set value for `LLVM_TOOL__BUILD` variables will get overwriten, likely without the user noticing. Hopefully the above shouldn't matter in practice because the LLVM_TOOL__BUILD variables are not documented, but LLVM_ENABLE_PROJECTS is. We should probably deprecate the `LLVM_TOOL__BUILD` variables at some point by turning them into to regular CMake variables that don't live in the CMake cache. Differential Revision: https://reviews.llvm.org/D57535 llvm-svn: 353148 --- diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt index 168ec6a..60d6df9 100644 --- a/llvm/CMakeLists.txt +++ b/llvm/CMakeLists.txt @@ -110,21 +110,60 @@ set(LLVM_ENABLE_PROJECTS "" CACHE STRING if( LLVM_ENABLE_PROJECTS STREQUAL "all" ) set( LLVM_ENABLE_PROJECTS ${LLVM_ALL_PROJECTS}) endif() -foreach(proj ${LLVM_ENABLE_PROJECTS}) - set(PROJ_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../${proj}") - if(NOT EXISTS "${PROJ_DIR}" OR NOT IS_DIRECTORY "${PROJ_DIR}") - message(FATAL_ERROR "LLVM_ENABLE_PROJECTS requests ${proj} but directory not found: ${PROJ_DIR}") - endif() - string(TOUPPER "${proj}" upper_proj) - STRING(REGEX REPLACE "-" "_" upper_proj ${upper_proj}) - set(LLVM_EXTERNAL_${upper_proj}_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../${proj}") - # There is a widely spread opinion that clang-tools-extra should be merged - # into clang. The following simulates it by always enabling clang-tools-extra - # when enabling clang. - if (proj STREQUAL "clang") - set(LLVM_EXTERNAL_CLANG_TOOLS_EXTRA_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../clang-tools-extra") - endif() -endforeach() + +# LLVM_ENABLE_PROJECTS_USED is `ON` if the user has ever used the +# `LLVM_ENABLE_PROJECTS` CMake cache variable. This exists for +# several reasons: +# +# * As an indicator that the `LLVM_ENABLE_PROJECTS` list is now the single +# source of truth for which projects to build. This means we will ignore user +# supplied `LLVM_TOOL__BUILD` CMake cache variables and overwrite +# them. +# +# * The case where the user previously had `LLVM_ENABLE_PROJECTS` set to a +# non-empty list but now the user wishes to disable building all other projects +# by setting `LLVM_ENABLE_PROJECTS` to an empty string. In that case we still +# need to set the `LLVM_TOOL_${upper_proj}_BUILD` variables so that we disable +# building all the projects that were previously enabled. +set(LLVM_ENABLE_PROJECTS_USED OFF CACHE BOOL "") +mark_as_advanced(LLVM_ENABLE_PROJECTS_USED) + +if (LLVM_ENABLE_PROJECTS_USED OR NOT LLVM_ENABLE_PROJECTS STREQUAL "") + set(LLVM_ENABLE_PROJECTS_USED ON CACHE BOOL "" FORCE) + foreach(proj ${LLVM_ALL_PROJECTS}) + string(TOUPPER "${proj}" upper_proj) + string(REGEX REPLACE "-" "_" upper_proj ${upper_proj}) + if ("${proj}" IN_LIST LLVM_ENABLE_PROJECTS) + message(STATUS "${proj} project is enabled") + set(SHOULD_ENABLE_PROJECT TRUE) + set(PROJ_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../${proj}") + if(NOT EXISTS "${PROJ_DIR}" OR NOT IS_DIRECTORY "${PROJ_DIR}") + message(FATAL_ERROR "LLVM_ENABLE_PROJECTS requests ${proj} but directory not found: ${PROJ_DIR}") + endif() + set(LLVM_EXTERNAL_${upper_proj}_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../${proj}") + # There is a widely spread opinion that clang-tools-extra should be merged + # into clang. The following simulates it by always enabling clang-tools-extra + # when enabling clang. + if (proj STREQUAL "clang") + set(LLVM_EXTERNAL_CLANG_TOOLS_EXTRA_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../clang-tools-extra") + endif() + else() + message(STATUS "${proj} project is disabled") + set(SHOULD_ENABLE_PROJECT FALSE) + endif() + # Force `LLVM_TOOL_${upper_proj}_BUILD` variables to have values that + # corresponds with `LLVM_ENABLE_PROJECTS`. This prevents the user setting + # `LLVM_TOOL_${upper_proj}_BUILD` variables externally. At some point + # we should deprecate allowing users to set these variables by turning them + # into normal CMake variables rather than cache variables. + set(LLVM_TOOL_${upper_proj}_BUILD + ${SHOULD_ENABLE_PROJECT} + CACHE + BOOL "Whether to build ${upper_proj} as part of LLVM" FORCE + ) + endforeach() +endif() +unset(SHOULD_ENABLE_PROJECT) # Build llvm with ccache if the package is present set(LLVM_CCACHE_BUILD OFF CACHE BOOL "Set to ON for a ccache enabled build")