[libc++] Define all CMake configuration features in the same location (#115361)

This moves the configuration of the CMake features to turn off RTTI,
exceptions and friends to the beginning of the CMake file, where we
configure other optional parts of the library.

This fixes an important bug where we would disable the benchmarks
because these options were not defined yet, leading to the build
thinking they were defined to OFF.

Author: ldionne

libcxx/CMakeLists.txt

@@ -47,6 +47,10 @@ include(HandleCompilerRT)
 # Basic options ---------------------------------------------------------------
 option(LIBCXX_ENABLE_SHARED "Build libc++ as a shared library." ON)
 option(LIBCXX_ENABLE_STATIC "Build libc++ as a static library." ON)
+option(LIBCXX_ENABLE_EXCEPTIONS "Enable exceptions in the built library." ON)
+option(LIBCXX_ENABLE_RTTI
+  "Use runtime type information.
+  This option may only be set to OFF when LIBCXX_ENABLE_EXCEPTIONS=OFF." ON)
 option(LIBCXX_ENABLE_FILESYSTEM
   "Whether to include support for parts of the library that rely on a filesystem being
    available on the platform. This includes things like most parts of <filesystem> and
@@ -97,6 +101,10 @@ option(LIBCXX_ENABLE_WIDE_CHARACTERS
    support the C functionality for wide characters. When wide characters are
    not supported, several parts of the library will be disabled, notably the
    wide character specializations of std::basic_string." ON)
+option(LIBCXX_ENABLE_THREADS "Build libc++ with support for threads." ON)
+option(LIBCXX_ENABLE_MONOTONIC_CLOCK
+  "Build libc++ with support for a monotonic clock.
+  This option may only be set to OFF when LIBCXX_ENABLE_THREADS=OFF." ON)
 
 # To use time zone support in libc++ the platform needs to have the IANA
 # database installed. Libc++ will fail to build if this is enabled on a
@@ -284,14 +292,6 @@ if (LIBCXX_BUILD_32_BITS)
 endif()
 
 # Feature options -------------------------------------------------------------
-option(LIBCXX_ENABLE_EXCEPTIONS "Use exceptions." ON)
-option(LIBCXX_ENABLE_RTTI
-  "Use runtime type information.
-   This option may only be set to OFF when LIBCXX_ENABLE_EXCEPTIONS=OFF." ON)
-option(LIBCXX_ENABLE_THREADS "Build libc++ with support for threads." ON)
-option(LIBCXX_ENABLE_MONOTONIC_CLOCK
-  "Build libc++ with support for a monotonic clock.
-   This option may only be set to OFF when LIBCXX_ENABLE_THREADS=OFF." ON)
 option(LIBCXX_HAS_MUSL_LIBC "Build libc++ with support for the Musl C library" OFF)
 option(LIBCXX_HAS_PTHREAD_API "Ignore auto-detection and force use of pthread API" OFF)
 option(LIBCXX_HAS_WIN32_THREAD_API "Ignore auto-detection and force use of win32 thread API" OFF)

libcxx/utils/libcxx/test/format.py

@@ -345,7 +345,7 @@ def execute(self, test, litConfig):
                     ),
                 )
             steps = [
-                "%dbg(COMPILED WITH) %{cxx} %s %{flags} %{compile_flags} %{link_flags} %{benchmark_flags} -o %t.exe",
+                "%dbg(COMPILED WITH) %{cxx} %s %{flags} %{compile_flags} %{benchmark_flags} %{link_flags} -o %t.exe",
             ]
             if "enable-benchmarks=run" in test.config.available_features:
                 steps += ["%dbg(EXECUTED AS) %{exec} %t.exe"]