[libc++][CMake] Use debug MSVC runtimes when libc++ is built in debug mode

[EricWF]

Summary

This patch allows libc++ to be built against the debug MSVC runtimes instead of just the release ones.

[smeenai]

Awesome. LGTM except that force-removing the _DEBUG define and then linking against the debug libraries might cause some wonkiness.

CMakeLists.txt

394

We should be able to remove this now, right?

[EricWF]

In D28725#646325, @smeenai wrote:

Awesome. LGTM except that force-removing the _DEBUG define and then linking against the debug libraries might cause some wonkiness.

Ack. I'll update the patch to still force remove _DEBUG but then later re-add it under the correct circumstances.

CMakeLists.txt

394

I would still rather strip it and re-add it. Just incase it gets added by LLVM or another parent project.

[smeenai]

CMakeLists.txt

394

Not completely sure I understand. Isn't this gonna be coming from cmake itself?

[EricWF]

• Address inline comments.
• Stop MSVC's default assertion handler from opening a new dialog window on failure.

[EricWF]

CMakeLists.txt

394

Yes, that was the original reason. Although it's possible an evil user could also add it.

I would rather handle it manually instead of depending on implicit default flags.

[EricWF]

I think this patch is ready to go. @smeenai any last words?

[smeenai]

CMakeLists.txt

394

Ah, fair enough.

I think the /RTC1 doesn't need to be stripped out anymore, at least in debug mode (the extra checking might be useful).

test/support/set_windows_crt_report_mode.h

1 ↗

(On Diff #84437)

Does this need the LLVM license header?

[smeenai]

LGTM apart from minor comments.

[EricWF]

• Address inline comments.

CMakeLists.txt

 
 # Configure coverage options.
 if (LIBCXX_GENERATE_COVERAGE)
   include(CodeCoverage)
   set(CMAKE_BUILD_TYPE "COVERAGE" CACHE STRING "" FORCE)
 endif()
 
 string(TOUPPER "${CMAKE_BUILD_TYPE}" uppercase_CMAKE_BUILD_TYPE)
+if (uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
+  set(LIBCXX_DEBUG_BUILD ON)
+else()
+  set(LIBCXX_DEBUG_BUILD OFF)
+endif()
 
 #===============================================================================
 # Setup Compiler Flags
 #===============================================================================
 
 include(HandleLibCXXABI) # Setup the ABI library flags
 
 if (NOT LIBCXX_STANDALONE_BUILD)
   # Remove flags that may have snuck in.
   remove_flags(-DNDEBUG -UNDEBUG -D_DEBUG
                -lc++abi -m32)
 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.
 remove_flags(-Wno-pedantic -pedantic-errors -pedantic)
 
 # Required flags ==============================================================
 set(LIBCXX_STANDARD_VER c++11 CACHE INTERNAL "internal option to change build dialect")

lib/CMakeLists.txt

else()
     add_interface_library(unwind)
   endif()
 endif()
 
 # Setup flags.
 if (NOT WIN32)
   add_flags_if_supported(-fPIC)
 endif()
+
 add_link_flags_if_supported(-nodefaultlibs)
 
 if (LIBCXX_TARGETING_MSVC)
+  if (LIBCXX_DEBUG_BUILD)
+    set(LIB_SUFFIX "d")
+  else()
+    set(LIB_SUFFIX "")
+  endif()
   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
+
+  add_library_flags(ucrt${LIB_SUFFIX}) # Universal C runtime
+  add_library_flags(vcruntime${LIB_SUFFIX}) # C++ runtime
+  add_library_flags(msvcrt${LIB_SUFFIX}) # 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

test/CMakeLists.txt

 pythonize_bool(LIBCXX_ENABLE_SHARED)
 pythonize_bool(LIBCXX_BUILD_32_BITS)
 pythonize_bool(LIBCXX_GENERATE_COVERAGE)
 pythonize_bool(LIBCXXABI_ENABLE_SHARED)
 pythonize_bool(LIBCXXABI_USE_LLVM_UNWINDER)
 pythonize_bool(LIBCXX_HAS_ATOMIC_LIB)
 pythonize_bool(LIBCXX_HAVE_CXX_ATOMICS_WITH_LIB)
 pythonize_bool(LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY)
+pythonize_bool(LIBCXX_DEBUG_BUILD)
 
 # By default, for non-standalone builds, libcxx and libcxxabi share a library
 # directory.
 if (NOT LIBCXX_CXX_ABI_LIBRARY_PATH)
   set(LIBCXX_CXX_ABI_LIBRARY_PATH "${LIBCXX_LIBRARY_DIR}" CACHE PATH
       "The path to libc++abi library.")
 endif()
 

test/libcxx/test/config.py

def print_config_info(self):
                              % self.cxx.compile_flags)
         if len(self.cxx.warning_flags):
             self.lit_config.note('Using warnings: %s' % self.cxx.warning_flags)
         self.lit_config.note('Using link flags: %s' % self.cxx.link_flags)
         # Print as list to prevent "set([...])" from being printed.
         self.lit_config.note('Using available_features: %s' %
                              list(self.config.available_features))
         self.lit_config.note('Using environment: %r' % self.exec_env)
+        sys.stderr.flush()  # Force flushing to avoid broken output on Windows
 
     def get_test_format(self):
         return LibcxxTestFormat(
             self.cxx,
             self.use_clang_verify,
             self.execute_external,
             self.executor,
             exec_env=self.exec_env)
def configure_link_flags_abi_library(self):
                         abs_path = os.path.join(cxxabi_library_root, libname)
                         self.cxx.link_flags += [abs_path]
                     else:
                         self.cxx.link_flags += ['-lc++abi']
         elif cxx_abi == 'libcxxrt':
             self.cxx.link_flags += ['-lcxxrt']
         elif cxx_abi == 'none' or cxx_abi == 'default':
             if self.is_windows:
-                self.cxx.link_flags += ['-lmsvcrt']
+                debug_suffix = 'd' \
+                    if self.get_lit_bool('debug_build', default=False) else ''
+                self.cxx.link_flags += ['-lmsvcrt%s' % debug_suffix]
         else:
             self.lit_config.fatal(
                 'C++ ABI setting %s unsupported for tests' % cxx_abi)
 
     def configure_extra_library_flags(self):
         if self.get_lit_bool('cxx_ext_threads', default=False):
             self.cxx.link_flags += ['-lc++external_threads']
         self.target_info.add_cxx_link_flags(self.cxx.link_flags)

test/lit.site.cfg.in

 config.sysroot                  = "@LIBCXX_SYSROOT@"
 config.gcc_toolchain            = "@LIBCXX_GCC_TOOLCHAIN@"
 config.generate_coverage        = "@LIBCXX_GENERATE_COVERAGE@"
 config.target_info              = "@LIBCXX_TARGET_INFO@"
 config.executor                 = "@LIBCXX_EXECUTOR@"
 config.llvm_unwinder            = "@LIBCXXABI_USE_LLVM_UNWINDER@"
 config.has_libatomic            = "@LIBCXX_HAS_ATOMIC_LIB@"
 config.use_libatomic            = "@LIBCXX_HAVE_CXX_ATOMICS_WITH_LIB@"
-
+config.debug_build              = "@LIBCXX_DEBUG_BUILD@"
 config.libcxxabi_shared         = "@LIBCXXABI_ENABLE_SHARED@"
 config.cxx_ext_threads          = "@LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY@"
 
 # Let the main config do the real work.
 config.loaded_site_config = True
 lit_config.load_config(config, "@LIBCXX_SOURCE_DIR@/test/lit.cfg")