[llvm] r351387 - [NFC] Factor out + document build requirements
JF Bastien via llvm-commits
llvm-commits at lists.llvm.org
Wed Jan 16 14:22:38 PST 2019
Author: jfb
Date: Wed Jan 16 14:22:38 2019
New Revision: 351387
URL: http://llvm.org/viewvc/llvm-project?rev=351387&view=rev
Log:
[NFC] Factor out + document build requirements
Summary: This change factors out compiler checking / warning, and documents LLVM_FORCE_USE_OLD_TOOLCHAIN. It doesn't introduce any functional changes nor policy changes, these will come late.
Subscribers: mgorny, jkorous, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D56799
Modified:
llvm/trunk/cmake/modules/CheckCompilerVersion.cmake
llvm/trunk/docs/CMake.rst
Modified: llvm/trunk/cmake/modules/CheckCompilerVersion.cmake
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/cmake/modules/CheckCompilerVersion.cmake?rev=351387&r1=351386&r2=351387&view=diff
==============================================================================
--- llvm/trunk/cmake/modules/CheckCompilerVersion.cmake (original)
+++ llvm/trunk/cmake/modules/CheckCompilerVersion.cmake Wed Jan 16 14:22:38 2019
@@ -1,52 +1,66 @@
-# Check if the host compiler is new enough. LLVM requires at least GCC 4.8,
-# MSVC 2015 (Update 3), or Clang 3.1.
+# Check if the host compiler is new enough.
+# These versions are updated based on the following policy:
+# llvm.org/docs/GettingStarted.html#host-c-toolchain-both-compiler-and-standard-library
include(CheckCXXSourceCompiles)
-if(NOT DEFINED LLVM_COMPILER_CHECKED)
- set(LLVM_COMPILER_CHECKED ON)
+set(GCC_MIN 4.8)
+set(GCC_WARN 4.8)
+set(CLANG_MIN 3.1)
+set(CLANG_WARN 3.1)
+set(APPLECLANG_MIN 3.1)
+set(APPLECLANG_WARN 3.1)
+set(MSVC_MIN 19.0)
+set(MSVC_WARN 19.00.24213.1)
- if(NOT LLVM_FORCE_USE_OLD_TOOLCHAIN)
- if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
- if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.8)
- message(FATAL_ERROR "Host GCC version must be at least 4.8!")
- endif()
- elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
- if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.1)
- message(FATAL_ERROR "Host Clang version must be at least 3.1!")
- endif()
-
- if (CMAKE_CXX_SIMULATE_ID MATCHES "MSVC")
- if (CMAKE_CXX_SIMULATE_VERSION VERSION_LESS 19.0)
- message(FATAL_ERROR "Host Clang must have at least -fms-compatibility-version=19.0")
- endif()
- set(CLANG_CL 1)
- elseif(NOT LLVM_ENABLE_LIBCXX)
- # Otherwise, test that we aren't using too old of a version of libstdc++
- # with the Clang compiler. This is tricky as there is no real way to
- # check the version of libstdc++ directly. Instead we test for a known
- # bug in libstdc++4.6 that is fixed in libstdc++4.7.
- set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
- set(OLD_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
- set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++0x")
- check_cxx_source_compiles("
+if(DEFINED LLVM_COMPILER_CHECKED)
+ return()
+endif()
+set(LLVM_COMPILER_CHECKED ON)
+
+if(LLVM_FORCE_USE_OLD_TOOLCHAIN)
+ return()
+endif()
+
+function(check_compiler_version NAME NICE_NAME MINIMUM_VERSION WARN_VERSION)
+ if(NOT CMAKE_CXX_COMPILER_ID STREQUAL NAME)
+ return()
+ endif()
+ if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS MINIMUM_VERSION)
+ message(FATAL_ERROR "Host ${NICE_NAME} version must be at least ${MINIMUM_VERSION}, your version is ${CMAKE_CXX_COMPILER_VERSION}.")
+ elseif(CMAKE_CXX_COMPILER_VERSION VERSION_LESS WARN_VERSION)
+ message(WARNING "Host ${NICE_NAME} version must be at least ${WARN_VERSION} due to miscompiles from earlier versions, your version is ${CMAKE_CXX_COMPILER_VERSION}.")
+ endif()
+endfunction(check_compiler_version)
+
+check_compiler_version("GNU" "GCC" ${GCC_MIN} ${GCC_WARN})
+check_compiler_version("Clang" "Clang" ${CLANG_MIN} ${CLANG_WARN})
+check_compiler_version("AppleClang" "Apple Clang" ${APPLECLANG_MIN} ${APPLECLANG_WARN})
+check_compiler_version("MSVC" "Visual Studio" ${MSVC_MIN} ${MSVC_WARN})
+
+if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+ if (CMAKE_CXX_SIMULATE_ID MATCHES "MSVC")
+ if (CMAKE_CXX_SIMULATE_VERSION VERSION_LESS MSVC_MIN)
+ message(FATAL_ERROR "Host Clang must have at least -fms-compatibility-version=${MSVC_MIN}, your version is ${CMAKE_CXX_COMPILER_VERSION}.")
+ endif()
+ set(CLANG_CL 1)
+ elseif(NOT LLVM_ENABLE_LIBCXX)
+ # Test that we aren't using too old of a version of libstdc++
+ # with the Clang compiler. This is tricky as there is no real way to
+ # check the version of libstdc++ directly. Instead we test for a known
+ # bug in libstdc++4.6 that is fixed in libstdc++4.7.
+ set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
+ set(OLD_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
+ set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++0x")
+ check_cxx_source_compiles("
#include <atomic>
std::atomic<float> x(0.0f);
int main() { return (float)x; }"
- LLVM_NO_OLD_LIBSTDCXX)
- if(NOT LLVM_NO_OLD_LIBSTDCXX)
- message(FATAL_ERROR "Host Clang must be able to find libstdc++4.8 or newer!")
- endif()
- set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
- set(CMAKE_REQUIRED_LIBRARIES ${OLD_CMAKE_REQUIRED_LIBRARIES})
- endif()
- elseif(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
- if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 19.0)
- message(FATAL_ERROR "Host Visual Studio must be at least 2015")
- elseif(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 19.00.24213.1)
- message(WARNING "Host Visual Studio should at least be 2015 Update 3 (MSVC 19.00.24213.1)"
- " due to miscompiles from earlier versions")
- endif()
+ LLVM_NO_OLD_LIBSTDCXX)
+ if(NOT LLVM_NO_OLD_LIBSTDCXX)
+ message(FATAL_ERROR "Host Clang must be able to find libstdc++4.8 or newer!")
endif()
+ set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
+ set(CMAKE_REQUIRED_LIBRARIES ${OLD_CMAKE_REQUIRED_LIBRARIES})
endif()
endif()
Modified: llvm/trunk/docs/CMake.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/CMake.rst?rev=351387&r1=351386&r2=351387&view=diff
==============================================================================
--- llvm/trunk/docs/CMake.rst (original)
+++ llvm/trunk/docs/CMake.rst Wed Jan 16 14:22:38 2019
@@ -573,6 +573,11 @@ LLVM-specific variables
options, which are passed to the CCACHE_MAXSIZE and CCACHE_DIR environment
variables, respectively.
+**LLVM_FORCE_USE_OLD_TOOLCHAIN**:BOOL
+ If enabled, the compiler and standard library versions won't be checked. LLVM
+ may not compile at all, or might fail at runtime due to known bugs in these
+ toolchains.
+
CMake Caches
============
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