build-libcxx: Build both static and shared libc++ in one single cmake build

Since bedf657d0f4c54ffe9ef4303382657a74296b544 in llvm-project
(May 18th), a static libc++ built at the same time as a shared one
no longer contain dllexport directives, making that library actually
usable.

Since dfa88927ae1411ccc3b248b7e624f2acf623d947 (Jun 6th), the
libc++ headers no longer have dllimport attributes, making the headers
installed from a build containing a shared library usable both
for the shared and static library, without the user having to set
any specific defines.

These two changes allow removing the manual build workarounds of
building the libraries in separate CMake invocations in a specific
order.

build-libcxx.sh

@@ -16,18 +16,18 @@
 
 set -e
 
-BUILD_STATIC=1
-BUILD_SHARED=1
+BUILD_STATIC=ON
+BUILD_SHARED=ON
 
 while [ $# -gt 0 ]; do
     if [ "$1" = "--disable-shared" ]; then
-        BUILD_SHARED=
+        BUILD_SHARED=OFF
     elif [ "$1" = "--enable-shared" ]; then
-        BUILD_SHARED=1
+        BUILD_SHARED=ON
     elif [ "$1" = "--disable-static" ]; then
-        BUILD_STATIC=
+        BUILD_STATIC=OFF
     elif [ "$1" = "--enable-static" ]; then
-        BUILD_STATIC=1
+        BUILD_STATIC=ON
     else
         PREFIX="$1"
     fi
@@ -74,62 +74,44 @@ else
     BUILDCMD=make
 fi
 
-build_all() {
-    type="$1"
-    CMAKEFLAGS=""
-    if [ "$type" = "shared" ]; then
-        SHARED=TRUE
-        STATIC=FALSE
-        CMAKEFLAGS="$CMAKEFLAGS -DLIBCXXABI_USE_LLVM_UNWINDER=ON"
-    else
-        SHARED=FALSE
-        STATIC=TRUE
-    fi
+for arch in $ARCHS; do
+    [ -z "$CLEAN" ] || rm -rf build-$arch
+    mkdir -p build-$arch
+    cd build-$arch
+    cmake \
+        ${CMAKE_GENERATOR+-G} "$CMAKE_GENERATOR" \
+        -DCMAKE_BUILD_TYPE=Release \
+        -DCMAKE_INSTALL_PREFIX="$PREFIX/$arch-w64-mingw32" \
+        -DCMAKE_C_COMPILER=$arch-w64-mingw32-clang \
+        -DCMAKE_CXX_COMPILER=$arch-w64-mingw32-clang++ \
+        -DCMAKE_CXX_COMPILER_TARGET=$arch-w64-windows-gnu \
+        -DCMAKE_CROSSCOMPILING=TRUE \
+        -DCMAKE_SYSTEM_NAME=Windows \
+        -DCMAKE_C_COMPILER_WORKS=TRUE \
+        -DCMAKE_CXX_COMPILER_WORKS=TRUE \
+        -DLLVM_PATH="$LLVM_PATH" \
+        -DCMAKE_AR="$PREFIX/bin/llvm-ar" \
+        -DCMAKE_RANLIB="$PREFIX/bin/llvm-ranlib" \
+        -DLLVM_ENABLE_RUNTIMES="libunwind;libcxxabi;libcxx" \
+        -DLIBUNWIND_USE_COMPILER_RT=TRUE \
+        -DLIBUNWIND_ENABLE_SHARED=$BUILD_SHARED \
+        -DLIBUNWIND_ENABLE_STATIC=$BUILD_STATIC \
+        -DLIBCXX_USE_COMPILER_RT=ON \
+        -DLIBCXX_ENABLE_SHARED=$BUILD_SHARED \
+        -DLIBCXX_ENABLE_STATIC=$BUILD_STATIC \
+        -DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY=OFF \
+        -DLIBCXX_ENABLE_STATIC_ABI_LIBRARY=TRUE \
+        -DLIBCXX_CXX_ABI=libcxxabi \
+        -DLIBCXX_LIBDIR_SUFFIX="" \
+        -DLIBCXX_INCLUDE_TESTS=FALSE \
+        -DLIBCXX_ENABLE_ABI_LINKER_SCRIPT=FALSE \
+        -DLIBCXXABI_USE_COMPILER_RT=ON \
+        -DLIBCXXABI_USE_LLVM_UNWINDER=ON \
+        -DLIBCXXABI_ENABLE_SHARED=OFF \
+        -DLIBCXXABI_LIBDIR_SUFFIX="" \
+        ..
 
-    for arch in $ARCHS; do
-        [ -z "$CLEAN" ] || rm -rf build-$arch-$type
-        mkdir -p build-$arch-$type
-        cd build-$arch-$type
-        cmake \
-            ${CMAKE_GENERATOR+-G} "$CMAKE_GENERATOR" \
-            -DCMAKE_BUILD_TYPE=Release \
-            -DCMAKE_INSTALL_PREFIX="$PREFIX/$arch-w64-mingw32" \
-            -DCMAKE_C_COMPILER=$arch-w64-mingw32-clang \
-            -DCMAKE_CXX_COMPILER=$arch-w64-mingw32-clang++ \
-            -DCMAKE_CXX_COMPILER_TARGET=$arch-w64-windows-gnu \
-            -DCMAKE_CROSSCOMPILING=TRUE \
-            -DCMAKE_SYSTEM_NAME=Windows \
-            -DCMAKE_C_COMPILER_WORKS=TRUE \
-            -DCMAKE_CXX_COMPILER_WORKS=TRUE \
-            -DLLVM_PATH="$LLVM_PATH" \
-            -DCMAKE_AR="$PREFIX/bin/llvm-ar" \
-            -DCMAKE_RANLIB="$PREFIX/bin/llvm-ranlib" \
-            -DLLVM_ENABLE_RUNTIMES="libunwind;libcxxabi;libcxx" \
-            -DLIBUNWIND_USE_COMPILER_RT=TRUE \
-            -DLIBUNWIND_ENABLE_SHARED=$SHARED \
-            -DLIBUNWIND_ENABLE_STATIC=$STATIC \
-            -DLIBCXX_USE_COMPILER_RT=ON \
-            -DLIBCXX_ENABLE_SHARED=$SHARED \
-            -DLIBCXX_ENABLE_STATIC=$STATIC \
-            -DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY=OFF \
-            -DLIBCXX_ENABLE_STATIC_ABI_LIBRARY=TRUE \
-            -DLIBCXX_CXX_ABI=libcxxabi \
-            -DLIBCXX_LIBDIR_SUFFIX="" \
-            -DLIBCXX_INCLUDE_TESTS=FALSE \
-            -DLIBCXX_ENABLE_ABI_LINKER_SCRIPT=FALSE \
-            -DLIBCXXABI_USE_COMPILER_RT=ON \
-            -DLIBCXXABI_ENABLE_SHARED=OFF \
-            -DLIBCXXABI_LIBDIR_SUFFIX="" \
-            $CMAKEFLAGS \
-            ..
-
-        $BUILDCMD ${CORES+-j$CORES}
-        $BUILDCMD install
-        cd ..
-    done
-}
-
-# Build shared first and static afterwards; the headers for static linking also
-# work when linking against the DLL, but not vice versa.
-[ -z "$BUILD_SHARED" ] || build_all shared
-[ -z "$BUILD_STATIC" ] || build_all static
+    $BUILDCMD ${CORES+-j$CORES}
+    $BUILDCMD install
+    cd ..
+done