[libc++] Add a picolibc test configuration with exceptions enabled (#75462)

libcxx/cmake/caches/Armv7M-picolibc.cmake

@@ -13,17 +13,18 @@ set(COMPILER_RT_BUILD_XRAY OFF CACHE BOOL "")
 set(COMPILER_RT_DEFAULT_TARGET_ONLY ON CACHE BOOL "")
 set(LIBCXXABI_BAREMETAL ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_ASSERTIONS OFF CACHE BOOL "")
-set(LIBCXXABI_ENABLE_EXCEPTIONS OFF CACHE BOOL "")
+set(LIBCXXABI_ENABLE_EXCEPTIONS ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
 set(LIBCXXABI_ENABLE_STATIC ON CACHE BOOL "")
+set(LIBCXXABI_ENABLE_STATIC_UNWINDER ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_THREADS OFF CACHE BOOL "")
 set(LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")
 set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
-set(LIBCXX_ENABLE_EXCEPTIONS OFF CACHE BOOL "")
+set(LIBCXX_ENABLE_EXCEPTIONS ON CACHE BOOL "")
 set(LIBCXX_ENABLE_FILESYSTEM OFF CACHE STRING "")
 set(LIBCXX_ENABLE_MONOTONIC_CLOCK OFF CACHE BOOL "")
 set(LIBCXX_ENABLE_RANDOM_DEVICE OFF CACHE BOOL "")
-set(LIBCXX_ENABLE_RTTI OFF CACHE BOOL "")
+set(LIBCXX_ENABLE_RTTI ON CACHE BOOL "")
 set(LIBCXX_ENABLE_SHARED OFF CACHE BOOL "")
 set(LIBCXX_ENABLE_STATIC ON CACHE BOOL "")
 set(LIBCXX_ENABLE_THREADS OFF CACHE BOOL "")

libcxx/utils/ci/buildkite-pipeline.yml

@@ -224,6 +224,13 @@ steps:
       arch: aarch64
     <<: *common
 
+  - label: Armv7-M picolibc -fno-exceptions
+    command: libcxx/utils/ci/run-buildbot armv7m-picolibc-no-exceptions
+    agents:
+      queue: libcxx-builders-linaro-arm
+      arch: aarch64
+    <<: *common
+
 - group: AIX
   steps:
   - label: AIX (32-bit)

libcxx/utils/ci/run-buildbot

@@ -203,6 +203,43 @@ function check-cxx-benchmarks() {
     ${NINJA} -vC "${BUILD_DIR}" check-cxx-benchmarks
 }
 
+function test-armv7m-picolibc() {
+    clean
+
+    # To make it easier to get this builder up and running, build picolibc
+    # from scratch. Anecdotally, the build-picolibc script takes about 16 seconds.
+    # This could be optimised by building picolibc into the Docker container.
+    ${MONOREPO_ROOT}/libcxx/utils/ci/build-picolibc.sh \
+        --build-dir "${BUILD_DIR}" \
+        --install-dir "${INSTALL_DIR}" \
+        --target armv7m-none-eabi
+
+    echo "--- Generating CMake"
+    flags="--sysroot=${INSTALL_DIR}"
+    ${CMAKE} \
+        -S "${MONOREPO_ROOT}/compiler-rt" \
+        -B "${BUILD_DIR}/compiler-rt" \
+        -GNinja -DCMAKE_MAKE_PROGRAM="${NINJA}" \
+        -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+        -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}" \
+        -DCMAKE_C_FLAGS="${flags}" \
+        -DCMAKE_CXX_FLAGS="${flags}" \
+        -DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON \
+        "${@}"
+    generate-cmake \
+        -DLIBCXX_TEST_CONFIG="armv7m-picolibc-libc++.cfg.in" \
+        -DLIBCXXABI_TEST_CONFIG="armv7m-picolibc-libc++abi.cfg.in" \
+        -DLIBUNWIND_TEST_CONFIG="armv7m-picolibc-libunwind.cfg.in" \
+        -DCMAKE_C_FLAGS="${flags}" \
+        -DCMAKE_CXX_FLAGS="${flags}" \
+        "${@}"
+
+    ${NINJA} -vC "${BUILD_DIR}/compiler-rt" install
+    mv "${BUILD_DIR}/install/lib/armv7m-none-eabi"/* "${BUILD_DIR}/install/lib"
+
+    check-runtimes
+}
+
 # Print the version of a few tools to aid diagnostics in some cases
 ${CMAKE} --version
 ${NINJA} --version
@@ -616,39 +653,16 @@ armv7-no-exceptions)
     check-runtimes
 ;;
 armv7m-picolibc)
-    clean
-
-    # To make it easier to get this builder up and running, build picolibc
-    # from scratch. Anecdotally, the build-picolibc script takes about 16 seconds.
-    # This could be optimised by building picolibc into the Docker container.
-    ${MONOREPO_ROOT}/libcxx/utils/ci/build-picolibc.sh \
-        --build-dir "${BUILD_DIR}" \
-        --install-dir "${INSTALL_DIR}" \
-        --target armv7m-none-eabi
-
-    echo "--- Generating CMake"
-    flags="--sysroot=${INSTALL_DIR}"
-    ${CMAKE} \
-        -S "${MONOREPO_ROOT}/compiler-rt" \
-        -B "${BUILD_DIR}/compiler-rt" \
-        -GNinja -DCMAKE_MAKE_PROGRAM="${NINJA}" \
-        -DCMAKE_BUILD_TYPE=RelWithDebInfo \
-        -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}" \
+    test-armv7m-picolibc \
+        -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Armv7M-picolibc.cmake"
+;;
+armv7m-picolibc-no-exceptions)
+    test-armv7m-picolibc \
         -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Armv7M-picolibc.cmake" \
-        -DCMAKE_C_FLAGS="${flags}" \
-        -DCMAKE_CXX_FLAGS="${flags}" \
-        -DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON
-    generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Armv7M-picolibc.cmake" \
-        -DLIBCXX_TEST_CONFIG="armv7m-picolibc-libc++.cfg.in" \
-        -DLIBCXXABI_TEST_CONFIG="armv7m-picolibc-libc++abi.cfg.in" \
-        -DLIBUNWIND_TEST_CONFIG="armv7m-picolibc-libunwind.cfg.in" \
-        -DCMAKE_C_FLAGS="${flags}" \
-        -DCMAKE_CXX_FLAGS="${flags}"
-
-    ${NINJA} -vC "${BUILD_DIR}/compiler-rt" install
-    mv "${BUILD_DIR}/install/lib/armv7m-none-eabi"/* "${BUILD_DIR}/install/lib"
-
-    check-runtimes
+        -DLIBCXXABI_ENABLE_EXCEPTIONS=OFF \
+        -DLIBCXXABI_ENABLE_STATIC_UNWINDER=OFF \
+        -DLIBCXX_ENABLE_EXCEPTIONS=OFF \
+        -DLIBCXX_ENABLE_RTTI=OFF
 ;;
 clang-cl-dll)
     clean

libcxxabi/test/catch_multi_level_pointer.pass.cpp

@@ -11,6 +11,10 @@
 // 1b00fc5d8133 made it in the dylib in macOS 10.11
 // XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx10.{{9|10}}
 
+// mps2-an385 machine used for testing of picolibc has just 4 MB of "flash"
+// memory and this test requires almost 5 MB
+// UNSUPPORTED: LIBCXX-PICOLIBC-FIXME
+
 #include <cassert>
 #include <cstdio>
 #include <cstdlib>