picolibc: Add configuration to select picolibc as the system libc

This moves the picolibc configuration values under C-library -> picolibc
so that they will be more easily discovered.

Signed-off-by: Joakim Nohlgård <joakim@nohlgard.se>
This commit is contained in:
Joakim Nohlgård 2022-11-30 01:09:14 +01:00 committed by Chris Packham
parent 9e13e83068
commit 1a362b5607
4 changed files with 252 additions and 184 deletions

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@ -1,6 +1,9 @@
# picolibc options
# picolibc companion library options
## no-package
## depends on BARE_METAL && CONFIGURE_has_meson && CONFIGURE_has_ninja
## depends on !LIBC_PICOLIBC
## select LIBC_PICOLIBC_SHOW
## help This option adds Picolibc to an existing configuration which may have
## help a C library, allowing you to install both and select between them
@ -9,124 +12,21 @@
## help Picolibc is a C library intended for use on embedded systems. It is a
## help conglomeration of several library parts, all under BSD-compatible software
## help licenses that make them easily usable on embedded products.
## help
## help Configuration for picolibc can be found under:
## help -> C-library
## help -> picolibc
config LIBC_PICOLIBC_GCC_LIBSTDCXX
bool
prompt "Compile libstdc++ picolibc variant"
prompt "Compile companion libstdc++ picolibc variant"
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.specs"
is specified.
the picolibc companion library. This version is linked when
"--specs=picolibcpp.specs" is specified.
config LIBC_PICOLIBC_CXA_ATEXIT
def_bool y
select LIBC_PROVIDES_CXA_ATEXIT
config LIBC_PICOLIBC_TARGET_CFLAGS
string
prompt "Target CFLAGS for picolibc"
default ""
help
Used to add specific options when compiling the target libraries
(eg. -ffunction-sections -fdata-sections), which can't be defined
in global TARGET_CFLAGS, because they shall be not used for the
gcc target libraries.
Note: Both TARGET_CFLAGS and LIBC_PICOLIBC_TARGET_CFLAGS are used
to compile the libraries.
Leave blank if you don't know better.
config LIBC_PICOLIBC_IO_C99FMT
bool
prompt "Enable IOs on C99 formats"
default y
help
Enable support for IOs on C99 formats.
config LIBC_PICOLIBC_REGISTER_FINI
bool
prompt "Enable finalization function registration using atexit"
help
Enable finalization function registration using atexit.
config LIBC_PICOLIBC_ATEXIT_DYNAMIC_ALLOC
bool
prompt "Enable dynamic allocation of atexit entries"
help
Enable dynamic allocation of atexit entries.
config LIBC_PICOLIBC_GLOBAL_ATEXIT
bool
prompt "Enable atexit data structure as global variable"
help
Enable atexit data structure as global variable, instead
of being thread-local.
config LIBC_PICOLIBC_LITE_EXIT
bool
prompt "Enable lite exit"
default y
help
Enable lite exit, a size-reduced implementation of exit that doesn't
invoke clean-up functions such as _fini or global destructors.
config LIBC_PICOLIBC_MULTITHREAD
bool
prompt "Enable support for multiple threads"
default y
help
Enable support for multiple threads.
config LIBC_PICOLIBC_RETARGETABLE_LOCKING
bool
prompt "Enable retargetable locking"
default y
help
Enable retargetable locking to allow the operating system to override
the dummy lock functions defined within picolibc.
config LIBC_PICOLIBC_EXTRA_SECTIONS
bool
prompt "Place each function & data element in their own section"
help
Place each function & data symbol in their own section. This allows
the linker to garbage collect unused symbols at link time.
config LIBC_PICOLIBC_ENABLE_TARGET_OPTSPACE
bool
prompt "Optimize picolibc for size"
default y
help
Pass --enable-target-optspace to picolibc configure.
This will compile picolibc with -Os.
config LIBC_PICOLIBC_LTO
bool
prompt "Enable Link Time Optimization"
depends on CC_GCC_USE_LTO
help
Builds the libraries with -flto to enable more aggressive link time
optimization. You will need to add -flto-partition=one to your
application's link line to keep the RETURN assembler macro together
with it's consumers.
config LIBC_PICOLIBC_NANO_MALLOC
bool
prompt "Enable Nano Malloc"
default y
help
PICOLIBC has two implementations of malloc family's functions, one in
`mallocr.c' and the other one in `nano-mallocr.c'. This options
enables the nano-malloc implementation, which is for small systems
with very limited memory. Note that this implementation does not
support `--enable-malloc-debugging' any more.
config LIBC_PICOLIBC_EXTRA_CONFIG_ARRAY
string
prompt "Extra config for picolibc"
default ""
help
Extra flags to pass to meson when configuring picolibc.
comment "Configuration for picolibc can be found under"
comment "* -> C-library"
comment "* -> picolibc"

125
config/libc/picolibc.in Normal file
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@ -0,0 +1,125 @@
# picolibc options
## depends on BARE_METAL && CONFIGURE_has_meson && CONFIGURE_has_ninja
## select CC_CORE_NEEDED
## select LIBC_SUPPORT_THREADS_NATIVE
## help Picolibc is a C library intended for use on embedded systems. It is a
## help conglomeration of several library parts, all under BSD-compatible software
## help licenses that make them easily usable on embedded products.
## help
## help This requres GCC with picolibc support which is only available
## help for GCC version 12.2.0 or later. A crosstool-ng dependency conflict
## help prevents that from being managed automatically.
##
config LIBC_PICOLIBC_CXA_ATEXIT
def_bool y
select LIBC_PROVIDES_CXA_ATEXIT
config LIBC_PICOLIBC_TARGET_CFLAGS
string
prompt "Target CFLAGS for picolibc"
default ""
help
Used to add specific options when compiling the target libraries
(eg. -ffunction-sections -fdata-sections), which can't be defined
in global TARGET_CFLAGS, because they shall be not used for the
gcc target libraries.
Note: Both TARGET_CFLAGS and LIBC_PICOLIBC_TARGET_CFLAGS are used
to compile the libraries.
Leave blank if you don't know better.
config LIBC_PICOLIBC_IO_C99FMT
bool
prompt "Enable IOs on C99 formats"
default y
help
Enable support for IOs on C99 formats.
config LIBC_PICOLIBC_REGISTER_FINI
bool
prompt "Enable finalization function registration using atexit"
help
Enable finalization function registration using atexit.
config LIBC_PICOLIBC_ATEXIT_DYNAMIC_ALLOC
bool
prompt "Enable dynamic allocation of atexit entries"
help
Enable dynamic allocation of atexit entries.
config LIBC_PICOLIBC_GLOBAL_ATEXIT
bool
prompt "Enable atexit data structure as global variable"
help
Enable atexit data structure as global variable, instead
of being thread-local.
config LIBC_PICOLIBC_LITE_EXIT
bool
prompt "Enable lite exit"
default y
help
Enable lite exit, a size-reduced implementation of exit that doesn't
invoke clean-up functions such as _fini or global destructors.
config LIBC_PICOLIBC_MULTITHREAD
bool
prompt "Enable support for multiple threads"
default y
help
Enable support for multiple threads.
config LIBC_PICOLIBC_RETARGETABLE_LOCKING
bool
prompt "Enable retargetable locking"
default y
help
Enable retargetable locking to allow the operating system to override
the dummy lock functions defined within picolibc.
config LIBC_PICOLIBC_EXTRA_SECTIONS
bool
prompt "Place each function & data element in their own section"
help
Place each function & data symbol in their own section. This allows
the linker to garbage collect unused symbols at link time.
config LIBC_PICOLIBC_ENABLE_TARGET_OPTSPACE
bool
prompt "Optimize picolibc for size"
default y
help
Pass --enable-target-optspace to picolibc configure.
This will compile picolibc with -Os.
config LIBC_PICOLIBC_LTO
bool
prompt "Enable Link Time Optimization"
depends on CC_GCC_USE_LTO
help
Builds the libraries with -flto to enable more aggressive link time
optimization. You will need to add -flto-partition=one to your
application's link line to keep the RETURN assembler macro together
with it's consumers.
config LIBC_PICOLIBC_NANO_MALLOC
bool
prompt "Enable Nano Malloc"
default y
help
PICOLIBC has two implementations of malloc family's functions, one in
`mallocr.c' and the other one in `nano-mallocr.c'. This options
enables the nano-malloc implementation, which is for small systems
with very limited memory. Note that this implementation does not
support `--enable-malloc-debugging' any more.
config LIBC_PICOLIBC_EXTRA_CONFIG_ARRAY
string
prompt "Extra config for picolibc"
default ""
help
Extra flags to pass to meson when configuring picolibc.

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@ -11,71 +11,13 @@ do_picolibc_for_build() { :; }
do_picolibc_for_host() { :; }
do_picolibc_for_target() { :; }
if [ "${CT_COMP_LIBS_PICOLIBC}" = "y" ]; then
if [ "${CT_LIBC_PICOLIBC}" = "y" -o "${CT_COMP_LIBS_PICOLIBC}" = "y" ]; then
# Download picolibc
do_picolibc_get() {
CT_Fetch PICOLIBC
}
do_picolibc_extract() {
CT_ExtractPatch PICOLIBC
}
#------------------------------------------------------------------------------
# Build an additional target libstdc++ with "-Os" (optimise for speed) option
# flag for libstdc++ "picolibc" variant.
do_cc_libstdcxx_picolibc()
{
local -a final_opts
local final_backend
if [ "${CT_LIBC_PICOLIBC_GCC_LIBSTDCXX}" = "y" ]; then
final_opts+=( "host=${CT_HOST}" )
final_opts+=( "libstdcxx_name=picolibc" )
final_opts+=( "prefix=${CT_PREFIX_DIR}" )
final_opts+=( "complibs=${CT_HOST_COMPLIBS_DIR}" )
final_opts+=( "cflags=${CT_CFLAGS_FOR_HOST}" )
final_opts+=( "ldflags=${CT_LDFLAGS_FOR_HOST}" )
final_opts+=( "lang_list=c,c++" )
final_opts+=( "build_step=libstdcxx" )
final_opts+=( "extra_config+=('--enable-stdio=stdio_pure')" )
final_opts+=( "extra_config+=('--disable-wchar_t')" )
if [ "${CT_LIBC_PICOLIBC_ENABLE_TARGET_OPTSPACE}" = "y" ]; then
final_opts+=( "enable_optspace=yes" )
fi
if [ "${CT_BARE_METAL}" = "y" ]; then
final_opts+=( "mode=baremetal" )
final_opts+=( "build_libgcc=yes" )
final_opts+=( "build_libstdcxx=yes" )
final_opts+=( "build_libgfortran=yes" )
if [ "${CT_STATIC_TOOLCHAIN}" = "y" ]; then
final_opts+=( "build_staticlinked=yes" )
fi
final_backend=do_gcc_core_backend
else
final_backend=do_gcc_backend
fi
CT_DoStep INFO "Installing libstdc++ picolibc"
CT_mkdir_pushd "${CT_BUILD_DIR}/build-cc-libstdcxx-picolibc"
"${final_backend}" "${final_opts[@]}"
CT_Popd
CT_EndStep
fi
}
do_picolibc_for_target() {
do_picolibc_common_install() {
local -a picolibc_opts
local cflags_for_target
CT_DoStep INFO "Installing Picolibc library"
CT_mkdir_pushd "${CT_BUILD_DIR}/build-picolibc-build-${CT_BUILD}"
CT_DoLog EXTRA "Configuring Picolibc library"
CT_DoLog EXTRA "Configuring C library"
# Multilib is the default, so if it is not enabled, disable it.
if [ "${CT_MULTILIB}" != "y" ]; then
@ -106,9 +48,6 @@ RETARGETABLE_LOCKING:newlib-retargetable-locking
fi
done
[ "${CT_USE_SYSROOT}" = "y" ] && \
picolibc_opts+=( "-Dsysroot-install=true" )
[ "${CT_LIBC_PICOLIBC_EXTRA_SECTIONS}" = "y" ] && \
CT_LIBC_PICOLIBC_TARGET_CFLAGS="${CT_LIBC_PICOLIBC_TARGET_CFLAGS} -ffunction-sections -fdata-sections"
@ -145,13 +84,24 @@ needs_exe_wrapper = true
skip_sanity_check = true
EOF
local picolibc_sysroot_dir
local picolibc_lib_dir
if [ "${CT_LIBC_PICOLIBC}" = 'y' ]; then
picolibc_sysroot_dir="${CT_SYSROOT_DIR}"
picolibc_lib_dir="${CT_SYSROOT_DIR}/lib"
picolibc_opts+=( '-Dsystem-libc=true' )
else
picolibc_sysroot_dir="${CT_PREFIX_DIR}/picolibc"
picolibc_lib_dir="${picolibc_sysroot_dir}/${CT_TARGET}/lib"
fi
CT_DoExecLog CFG \
meson \
--cross-file picolibc-cross.txt \
--prefix="${CT_PREFIX_DIR}" \
-Dincludedir=picolibc/include \
-Dlibdir=picolibc/${CT_TARGET}/lib \
-Dspecsdir="${CT_SYSROOT_DIR}"/lib \
--prefix="${picolibc_sysroot_dir}" \
-Dincludedir=include \
-Dlibdir="${picolibc_lib_dir}" \
-Dspecsdir="${CT_SYSROOT_DIR}/lib" \
"${CT_SRC_DIR}/picolibc" \
"${picolibc_opts[@]}" \
"${CT_LIBC_PICOLIBC_EXTRA_CONFIG_ARRAY[@]}"
@ -161,11 +111,75 @@ EOF
CT_DoLog EXTRA "Installing C library"
CT_DoExecLog ALL ninja install
}
fi # CT_LIBC_PICOLIBC -o CT_COMP_LIBS_PICOLIBC
if [ "${CT_COMP_LIBS_PICOLIBC}" = "y" ]; then
do_cc_libstdcxx_picolibc() { :; }
# Download picolibc
do_picolibc_get() {
CT_Fetch PICOLIBC
}
do_picolibc_extract() {
CT_ExtractPatch PICOLIBC
}
if [ "${CT_LIBC_PICOLIBC_GCC_LIBSTDCXX}" = "y" ]; then
#------------------------------------------------------------------------------
# Build an additional target libstdc++ with "-Os" (optimise for speed) option
# flag for libstdc++ "picolibc" variant.
do_cc_libstdcxx_picolibc()
{
local -a final_opts
local final_backend
final_opts+=( "host=${CT_HOST}" )
final_opts+=( "libstdcxx_name=picolibc" )
final_opts+=( "prefix=${CT_PREFIX_DIR}" )
final_opts+=( "complibs=${CT_HOST_COMPLIBS_DIR}" )
final_opts+=( "cflags=${CT_CFLAGS_FOR_HOST}" )
final_opts+=( "ldflags=${CT_LDFLAGS_FOR_HOST}" )
final_opts+=( "lang_list=c,c++" )
final_opts+=( "build_step=libstdcxx" )
final_opts+=( "extra_config+=('--enable-stdio=stdio_pure')" )
final_opts+=( "extra_config+=('--disable-wchar_t')" )
if [ "${CT_LIBC_PICOLIBC_ENABLE_TARGET_OPTSPACE}" = "y" ]; then
final_opts+=( "enable_optspace=yes" )
fi
if [ "${CT_BARE_METAL}" = "y" ]; then
final_opts+=( "mode=baremetal" )
final_opts+=( "build_libgcc=yes" )
final_opts+=( "build_libstdcxx=yes" )
final_opts+=( "build_libgfortran=yes" )
if [ "${CT_STATIC_TOOLCHAIN}" = "y" ]; then
final_opts+=( "build_staticlinked=yes" )
fi
final_backend=do_gcc_core_backend
else
final_backend=do_gcc_backend
fi
CT_DoStep INFO "Installing libstdc++ picolibc"
CT_mkdir_pushd "${CT_BUILD_DIR}/build-cc-libstdcxx-picolibc"
"${final_backend}" "${final_opts[@]}"
CT_Popd
CT_EndStep
}
fi # CT_LIBC_PICOLIBC_GCC_LIBSTDCXX
do_picolibc_for_target() {
CT_DoStep INFO "Installing Picolibc library"
CT_mkdir_pushd "${CT_BUILD_DIR}/build-picolibc-build-${CT_BUILD}"
do_picolibc_common_install
CT_Popd
CT_EndStep
do_cc_libstdcxx_picolibc
}
fi
fi # CT_COMP_LIBS_PICOLIBC

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@ -0,0 +1,29 @@
# This file adds functions to use the Picolibc library as the system libc
# Copyright © 2022 Joakim Nohlgård
# Licensed under the GPL v2 or later. See COPYING in the root of this package
picolibc_get()
{
CT_Fetch PICOLIBC
}
picolibc_extract()
{
CT_ExtractPatch PICOLIBC
}
picolibc_headers()
{
CT_DoStep INFO "Installing C library headers"
CT_DoExecLog ALL cp -a "${CT_SRC_DIR}/picolibc/newlib/libc/include/." "${CT_HEADERS_DIR}"
CT_EndStep
}
picolibc_main()
{
CT_DoStep INFO "Installing C library"
CT_mkdir_pushd "${CT_BUILD_DIR}/build-libc"
do_picolibc_common_install
CT_Popd
CT_EndStep
}