picolib: Add option to compile additional variant of stdc++

Compile additional variant of libstdc++ with exceptions disabled.

Signed-off-by: Adrian Gielniewski <[email protected]>

Author: adigie

config/comp_libs/picolibc.in

@@ -20,6 +20,16 @@ config LIBC_PICOLIBC_GCC_LIBSTDCXX
       picolibc. This version is linked when "--specs=picolibcpp.specs"
       is specified.
 
+config LIBC_PICOLIBC_GCC_LIBSTDCXX_NOEXCEPT
+    bool
+    prompt "Compile libstdc++ picolibc variant with exceptions disabled"
+    default y
+    depends on CC_LANG_CXX
+    help
+      This option compiles an additional target libstdc++ for use with
+      picolibc. This version is linked when "--specs=picolibcpp_noexcept.specs"
+      is specified.
+
 config LIBC_PICOLIBC_CXA_ATEXIT
     def_bool y
     select LIBC_PROVIDES_CXA_ATEXIT

samples/arm-picolibc-eabi/crosstool.config

@@ -9,3 +9,4 @@ CT_CC_GCC_MULTILIB_LIST="rmprofile"
 CT_CC_GCC_CONFIG_TLS=y
 CT_CC_LANG_CXX=y
 CT_COMP_LIBS_PICOLIBC=y
+CT_LIBC_PICOLIBC_GCC_LIBSTDCXX_NOEXCEPT=y

scripts/build/companion_libs/340-picolibc.sh

@@ -27,8 +27,10 @@ do_picolibc_extract() {
 # flag for libstdc++ "picolibc" variant.
 do_cc_libstdcxx_picolibc()
 {
+    local variant="$1"
     local -a final_opts
     local final_backend
+    local suffix=
 
     if [ "${CT_LIBC_PICOLIBC_GCC_LIBSTDCXX}" = "y" ]; then
         final_opts+=( "host=${CT_HOST}" )
@@ -46,6 +48,10 @@ do_cc_libstdcxx_picolibc()
         if [ "${CT_LIBC_PICOLIBC_ENABLE_TARGET_OPTSPACE}" = "y" ]; then
             final_opts+=( "enable_optspace=yes" )
         fi
+        if [ "${variant}" = "noexcept" ]; then
+            final_opts+=( "extra_cxxflags_for_target=-fno-exceptions" )
+            suffix="-noexcept"
+        fi
 
         if [ "${CT_BARE_METAL}" = "y" ]; then
             final_opts+=( "mode=baremetal" )
@@ -61,8 +67,9 @@ do_cc_libstdcxx_picolibc()
         fi
 
         CT_DoStep INFO "Installing libstdc++ picolibc"
-        CT_mkdir_pushd "${CT_BUILD_DIR}/build-cc-libstdcxx-picolibc"
+        CT_mkdir_pushd "${CT_BUILD_DIR}/build-cc-libstdcxx-picolibc${suffix}"
         "${final_backend}" "${final_opts[@]}"
+        # TODO: suffix
         CT_Popd
 
         CT_EndStep
@@ -170,6 +177,10 @@ EOF
 
     do_cc_libstdcxx_picolibc
 
+    if [ "${CT_LIBC_PICOLIBC_GCC_LIBSTDCXX_NOEXCEPT}" = "y" ]; then
+      do_cc_libstdcxx_picolibc noexcept
+    fi
+
     if [ "${CT_STRIP_TARGET_TOOLCHAIN_LIBRARIES}" = "y" ]; then
 
 	CT_DoStep INFO "Stripping Picolibc library"