Commit d50b31be authored by Brad King's avatar Brad King

Clang: For MSVC ABI do not use modes older than C++14

Since commit d44c0db0 (clang: setup correct configuration in gnu mode,
2019-02-20, v3.15.0-rc1~41^2~5) we support the GNU-like Clang that
targets the MSVC ABI.  However, Clang cannot compile with the MSVC
standard library unless it runs in a mode aware of C++14 (since MSVC
itself does not even have a lower mode).  When `CMAKE_CXX_STANDARD` is
set to 98 or 11, use C++14 anyway.

Since Clang's default mode is aware of C++14, another option is to not
add any flags for 98 or 11.  However, if a future Clang version ever
defaults to a higher C++ standard, setting the standard to 98 or 11
should at least not use a mode higher than 14.

Also revert test updates from commit 4819ff96 (Tests: fix failures
with gnu mode clang on windows, 2019-03-21, v3.15.0-rc1~41^2~3) that
were meant to work around the standard selection problem.

Fixes: #19496
parent 79bcf4e1
......@@ -58,6 +58,13 @@ if("x${CMAKE_CXX_COMPILER_FRONTEND_VARIANT}" STREQUAL "xGNU")
unset(_clang_version_std17)
if("x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
# The MSVC standard library requires C++14, and MSVC itself has no
# notion of operating in a mode not aware of at least that standard.
set(CMAKE_CXX98_STANDARD_COMPILE_OPTION "-std=c++14")
set(CMAKE_CXX98_EXTENSION_COMPILE_OPTION "-std=gnu++14")
set(CMAKE_CXX11_STANDARD_COMPILE_OPTION "-std=c++14")
set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "-std=gnu++14")
# This clang++ is missing some features because of MSVC compatibility.
unset(CMAKE_CXX11_STANDARD__HAS_FULL_SUPPORT)
unset(CMAKE_CXX14_STANDARD__HAS_FULL_SUPPORT)
......
......@@ -7,7 +7,7 @@ set(CMAKE_CXX_STANDARD 98)
# Clang/C2 in C++98 mode cannot properly handle some of MSVC headers
if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
CMAKE_CXX_SIMULATE_ID STREQUAL "MSVC")
set(CMAKE_CXX_STANDARD 14)
set(CMAKE_CXX_STANDARD 11)
endif()
add_library(foo SHARED empty.cpp)
......
......@@ -446,11 +446,6 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
set(CMAKE_CXX_STANDARD 11)
endif()
if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "GNU")
set(CMAKE_CXX_STANDARD 14)
endif()
#
# Create the libs and the main exe
#
......
......@@ -403,11 +403,6 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
set(CMAKE_CXX_STANDARD 11)
endif()
if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "GNU")
set(CMAKE_CXX_STANDARD 14)
endif()
#
# Create the libs and the main exe
#
......
......@@ -133,9 +133,7 @@ endif()
# for msvc the compiler version determines which c++11 features are available.
if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC"
OR (CMAKE_CXX_COMPILER_ID STREQUAL "Clang"
AND "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC"
AND "x${CMAKE_CXX_COMPILER_FRONTEND_VARIANT}" STREQUAL "xMSVC" ))
OR (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC"))
if(";${CMAKE_CXX_COMPILE_FEATURES};" MATCHES ";cxx_delegating_constructors;")
list(APPEND true_defs EXPECTED_COMPILER_CXX_DELEGATING_CONSTRUCTORS)
list(APPEND true_defs EXPECTED_COMPILER_CXX_VARIADIC_TEMPLATES)
......
......@@ -5,17 +5,6 @@ project(Plugin)
# We need proper C++98 support from the compiler
set(CMAKE_CXX_STANDARD 98)
# Clang/C2 in C++98 mode cannot properly handle some of MSVC headers
if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
CMAKE_CXX_SIMULATE_ID STREQUAL "MSVC")
set(CMAKE_CXX_STANDARD 11)
endif()
if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "GNU")
set(CMAKE_CXX_STANDARD 14)
endif()
# Test per-target output directory properties.
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${Plugin_BINARY_DIR}/bin)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${Plugin_BINARY_DIR}/lib/plugin)
......@@ -40,6 +29,12 @@ include_directories(
${Plugin_SOURCE_DIR}/include
)
# Clang/C2 in C++98 mode cannot properly handle some of MSVC headers
if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
CMAKE_CXX_SIMULATE_ID STREQUAL "MSVC")
set(CMAKE_CXX_STANDARD 11)
endif()
# Create an executable that exports an API for use by plugins.
add_executable(example_exe src/example_exe.cxx)
set_target_properties(example_exe PROPERTIES
......
......@@ -51,11 +51,6 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
set(CMAKE_CXX_STANDARD 11)
endif()
if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "GNU")
set(CMAKE_CXX_STANDARD 14)
endif()
add_subdirectory(lib_shared_and_static)
if(CMAKE_SYSTEM_NAME MATCHES "AIX" AND CMAKE_CXX_COMPILER_ID STREQUAL "GNU"
......
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