[libc++] [CMake] Link with /nodefaultlibs on Windows
Summary:
This patch attempts to fix the libc++ build/link so that it doesn't use an default C++ libraries on Windows. This is needed to prevent linking to MSVC's STL library.
Additionally this patch changes libc++ so that it is always linked with the non-debug DLL's (e.g. `/MD`). This is needed so that the test suite can correctly link the same libraries without needing to know which configuration `c++.dll` was linked with.
Reviewers: compnerd, rnk, majnemer, kimgr, awson, halyavin, smeenai
Subscribers: cfe-commits, mgorny
Differential Revision: https://reviews.llvm.org/D28441
llvm-svn: 292001
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index 9fa0ed3..b12910f 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -39,6 +39,12 @@
build directory and run 'cmake /path/to/${PROJECT_NAME} [options]' there."
)
+if (MSVC)
+ set(LIBCXX_TARGETING_MSVC ON)
+else()
+ set(LIBCXX_TARGETING_MSVC OFF)
+endif()
+
#===============================================================================
# Setup CMake Options
#===============================================================================
@@ -377,6 +383,11 @@
endif()
remove_flags(-stdlib=libc++ -stdlib=libstdc++)
+# FIXME: Remove all debug flags and flags that change which Windows
+# default libraries are linked. Currently we only support linking the
+# non-debug DLLs
+remove_flags("/D_DEBUG" "/MTd" "/MDd" "/MT" "/Md" "/RTC1")
+
# FIXME(EricWF): See the FIXME on LIBCXX_ENABLE_PEDANTIC.
# Remove the -pedantic flag and -Wno-pedantic and -pedantic-errors
# so they don't get transformed into -Wno and -errors respectivly.
@@ -476,7 +487,7 @@
define_if_not(LIBCXX_ENABLE_ASSERTIONS -DNDEBUG)
if (LIBCXX_ENABLE_ASSERTIONS)
# MSVC doesn't like _DEBUG on release builds. See PR 4379.
- define_if_not(MSVC -D_DEBUG)
+ define_if_not(LIBCXX_TARGETING_MSVC -D_DEBUG)
endif()
# Modules flags ===============================================================
diff --git a/libcxx/cmake/Modules/HandleLibcxxFlags.cmake b/libcxx/cmake/Modules/HandleLibcxxFlags.cmake
index 7077c6e..5ea69e4 100644
--- a/libcxx/cmake/Modules/HandleLibcxxFlags.cmake
+++ b/libcxx/cmake/Modules/HandleLibcxxFlags.cmake
@@ -26,6 +26,10 @@
# or added in other parts of LLVM's cmake configuration.
macro(remove_flags)
foreach(var ${ARGN})
+ string(REPLACE "${var}" "" CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
+ string(REPLACE "${var}" "" CMAKE_CXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_DEBUG}")
+ string(REPLACE "${var}" "" CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_DEBUG}")
+ string(REPLACE "${var}" "" CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_DEBUG}")
string(REPLACE "${var}" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
string(REPLACE "${var}" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
string(REPLACE "${var}" "" CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}")
diff --git a/libcxx/lib/CMakeLists.txt b/libcxx/lib/CMakeLists.txt
index cc3ed16..f83051f 100644
--- a/libcxx/lib/CMakeLists.txt
+++ b/libcxx/lib/CMakeLists.txt
@@ -104,6 +104,17 @@
endif()
add_link_flags_if_supported(-nodefaultlibs)
+if (LIBCXX_TARGETING_MSVC)
+ add_compile_flags(/Zl)
+ add_link_flags(/nodefaultlib)
+ add_library_flags(ucrt) # Universal C runtime
+ add_library_flags(vcruntime) # C++ runtime
+ add_library_flags(msvcrt) # C runtime startup files
+ # Required for standards-complaint wide character formatting functions
+ # (e.g. `printfw`/`scanfw`)
+ add_library_flags(iso_stdio_wide_specifiers)
+endif()
+
if (LIBCXX_OSX_REEXPORT_SYSTEM_ABI_LIBRARY)
if (NOT DEFINED LIBCXX_LIBCPPABI_VERSION)
set(LIBCXX_LIBCPPABI_VERSION "2") # Default value
diff --git a/libcxx/test/libcxx/test/config.py b/libcxx/test/libcxx/test/config.py
index 3c00a8b..448700f 100644
--- a/libcxx/test/libcxx/test/config.py
+++ b/libcxx/test/libcxx/test/config.py
@@ -667,7 +667,7 @@
self.cxx.link_flags += ['-lcxxrt']
elif cxx_abi == 'none' or cxx_abi == 'default':
if self.is_windows:
- self.cxx.link_flags += ['-lmsvcrtd']
+ self.cxx.link_flags += ['-lmsvcrt']
else:
self.lit_config.fatal(
'C++ ABI setting %s unsupported for tests' % cxx_abi)
