;;
esac
+# picolibc systems
+case "${target}_${with_picolibc}" in
+*-picolibc-*|*_yes)
+ default_use_cxa_atexit=yes
+ use_gcc_stdint=none
+ # add newlib-stdint.h if not already present
+ case "${tm_file}" in
+ *newlib-stdint.h*)
+ ;;
+ *)
+ tm_file="${tm_file} newlib-stdint.h"
+ ;;
+ esac
+ tm_file="${tm_file} picolibc-spec.h"
+ extra_options="${extra_options} picolibc.opt"
+ ;;
+esac
+
# Assume the existence of indirect function support and allow the use of the
# resolver attribute.
case ${target} in
--- /dev/null
+/* Configuration common to all targets running Picolibc.
+ Copyright (C) 2026 Free Software Foundation, Inc.
+
+ This file is part of GCC.
+
+ GCC is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published
+ by the Free Software Foundation; either version 3, or (at your
+ option) any later version.
+
+ GCC is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
+ License for more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#define PICOLIBC_LD "picolibc.ld"
+
+/* Default to local-exec TLS model. */
+#undef OS_CC1_SPEC
+#define OS_CC1_SPEC " %{!ftls-model=*:-ftls-model=local-exec}"
+
+/* Pass along preprocessor definitions when --printf or --scanf are specified */
+#define LIBC_CPP_SPEC \
+ " %{-printf=*: -D_PICOLIBC_PRINTF='%*'}" \
+ " %{-scanf=*: -D_PICOLIBC_SCANF='%*'}"
+
+/*
+ * Add picolibc.ld if not using -shared, -r or -T and we can find it.
+ * Define vfprintf if --printf is set
+ * Define vfscanf if --scanf is set
+ */
+#define LIBC_LINK_SPEC \
+ " %{!shared:%{!r:%{!T*: %:if-exists-then-else(%:find-file(" PICOLIBC_LD ") -T" PICOLIBC_LD ")}}}" \
+ " %{-printf=*:--defsym=" USER_LABEL_PREFIX "vfprintf=" USER_LABEL_PREFIX "__%*_vfprintf}" \
+ " %{-scanf=*:--defsym=" USER_LABEL_PREFIX "vfscanf=" USER_LABEL_PREFIX "__%*_vfscanf}"
+
+/*
+ * Place the C library, libgcc and any oslib in a link group to resolve
+ * interdependencies
+ */
+#undef LIB_SPEC
+#define LIB_SPEC "--start-group -lc %{-oslib=*:-l%*} %(libgcc) --end-group"
+
+/* Select alternate crt0 version if --crt0 is specified */
+#undef STARTFILE_SPEC
+#define STARTFILE_SPEC "%{-crt0=*:crt0-%*%O%s; :crt0%O%s}"
+
+#define EH_TABLES_CAN_BE_READ_ONLY 1
--- /dev/null
+; Processor-independent options for picolibc.
+;
+; Copyright (C) 2026 Free Software Foundation, Inc.
+;
+; This file is part of GCC.
+;
+; GCC is free software; you can redistribute it and/or modify it under
+; the terms of the GNU General Public License as published by the Free
+; Software Foundation; either version 3, or (at your option) any later
+; version.
+;
+; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+; WARRANTY; without even the implied warranty of MERCHANTABILITY or
+; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+; for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with GCC; see the file COPYING3. If not see
+; <http://www.gnu.org/licenses/>.
+
+-oslib
+Driver Separate Alias(-oslib=)
+
+-oslib=
+Driver Joined
+Specify an OS support library to load after libc.
+
+-crt0
+Driver Separate Alias(-crt0=)
+
+-crt0=
+Driver Joined
+Specify an alternate startup file.
+
+-printf
+Driver Separate Alias(-printf=)
+
+-printf=
+Driver Joined
+Specify the printf version linked from libc.
+
+-scanf
+Driver Separate Alias(-scanf=)
+
+-scanf=
+Driver Joined
+Specify the scanf version linked from libc.
--- /dev/null
+; Autogenerated by regenerate-opt-urls.py from gcc/config/picolibc.opt and generated HTML
+
enable_languages
with_multilib_list
with_multilib_generator
+with_picolibc
with_zstd
with_zstd_include
with_zstd_lib
RISC-V, SH and x86-64 only)
--with-multilib-generator
Multi-libs configuration string (RISC-V only)
+ --with-picolibc Support for picolibc, including command line options
+ and spec rules
--with-zstd=PATH specify prefix directory for installed zstd library.
Equivalent to --with-zstd-include=PATH/include plus
--with-zstd-lib=PATH/lib
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
-#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
-#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
-#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
-#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
-#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
fi
+
+# Check whether --with-picolibc was given.
+if test "${with_picolibc+set}" = set; then :
+ withval=$with_picolibc;
+fi
+
+
# -------------------------
# Checks for other programs
# -------------------------
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 21928 "configure"
+#line 21938 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 22034 "configure"
+#line 22044 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
:,
with_multilib_generator=default)
+AC_ARG_WITH(picolibc,
+[AS_HELP_STRING([--with-picolibc], [Support for picolibc, including command line options and spec rules])])
+
# -------------------------
# Checks for other programs
# -------------------------
* Link Options:: Specifying libraries and so on.
* Directory Options:: Where to find header files and libraries.
Where to find the compiler executable files.
+* Picolibc Options:: Select compile and link options when using picolibc.
* Code Gen Options:: Specifying conventions for function calls, data layout
and register usage.
* Developer Options:: Printing GCC configuration info, statistics, and
--no-canonical-prefixes --no-standard-includes
--prefix=@var{prefix} --sysroot=@var{dir}}
+@item Picolibc Options
+@xref{Picolibc Options,,Options for use with Picolibc}.
+@gccoptlist{--oslib=@var{library} --crt0=@r{[}none@r{|}minimal@r{|}hosted@r{|}semihost@r{]}
+--printf=@r{[}d@r{|}f@r{|}l@r{|}i@r{|}m@r{]} --scanf=@r{[}d@r{|}f@r{|}l@r{|}i@r{|}m@r{]}}
+
@item Code Generation Options
@xref{Code Gen Options,,Options for Code Generation Conventions}.
@gccoptlist{-fcall-saved-@var{reg} -fcall-used-@var{reg}
@end table
+@node Picolibc Options
+@section Options for use with Picolibc
+@cindex picolibc options
+@cindex options, picolibc
+
+These options control compilation and linking when using picolibc:
+
+@table @gcctabopt
+@opindex oslib
+@item --oslib=@var{library}
+Search the library named @var{library} after the C library, permitting
+symbols undefined by the C library to be defined by this library. The
+C library, libgcc and this library are placed between
+@option{--start-group} and @option{--end-group} flags so that each can
+refer to symbols in the others. For many targets, picolibc provides a
+@samp{semihost} variant (specified with @option{--oslib=semihost})
+which provides enough basic OS functionality to support console and
+file I/O when run in an emulator or when using an in-circuit debugger.
+
+@opindex crt0
+@item --crt0=@r{[}none@r{|}minimal@r{|}hosted@r{|}semihost@r{]}
+Replace the default @file{crt0.o} name with
+@file{crt0-@var{variant}.o}. The @samp{none} variant provides no
+startup code at all, allowing the user to supply their
+own. @samp{minimal} performs basic memory setup but does not invoke
+any constructors. When no @option{-crt0} option is provided, the
+default initialization code adds calls to all
+constructors. @samp{hosted} adds a call to @code{exit} when
+@code{main} returns. @samp{semihost} accesses a command line parameter
+supplied via the semihosting interface and splits that into arguments
+at whitespace boundaries, passing the resulting array of strings to
+main in @code{argc} and @code{argv}. On some targets, including
+aarch64, arc, arm, loongarch, m68k, riscv, super-h and x86,
+@samp{semihost} also traps hardware exceptions and prints information
+to the console. Note that @option{--crt0=semihost} depends upon APIs
+provided by @option{--oslib=semihost}.
+
+@opindex printf
+@item --printf=@r{[}d@r{|}f@r{|}l@r{|}i@r{|}m@r{]}
+Select the printf variant. Picolibc provides five different printf
+variants which offer decreasing levels of functionality along with
+decreasing code size. @samp{d} is the default level, offering full C17
+and POSIX.1-2024 conformance. @samp{f} provides the same feature set,
+but supports @code{float} values instead of @code{double} which are
+passed using the @code{printf_float} macro. @samp{l} elides all
+floating point and POSIX positional parameter support. @samp{i} limits
+integers to those no larger than @code{long}. @samp{m} removes support
+for most formatting options including width and precision. The formats
+and arguments are still parsed correctly, but output does not respect
+those parameters.
+
+@opindex scanf
+@item --scanf=@r{[}d@r{|}f@r{|}l@r{|}i@r{|}m@r{]}
+Select the scanf variant. Picolibc provides five different scanf
+variants which offer decreasing levels of functionality along with
+decreasing code size. @samp{d} is the default level, offering full C17
+and POSIX.1-2024 conformance. @samp{f} removes support for
+@code{double} values. @samp{l} elides all floating point
+support. @samp{i} limits integers to those no larger than
+@code{long}. @samp{m} removes support for @code{%[} conversion specifiers.
+
+@end table
+
@node Code Gen Options
@section Options for Code Generation Conventions
@cindex code generation conventions
Do not define this macro if it does not need to do anything.
@end defmac
+@defmac LIBC_CPP_SPEC
+A C string constant which is appended to the value of
+@code{CPP_SPEC}. @code{LIBC_CPP_SPEC} is intended to depend upon the
+C library in use.
+
+Do not define this macro if it does not need to do anything.
+@end defmac
+
@defmac CPLUSPLUS_CPP_SPEC
This macro is just like @code{CPP_SPEC}, but is used for C++, rather
than C@. If you do not define this macro, then the value of
Do not define this macro if it does not need to do anything.
@end defmac
+@defmac LIBC_LINK_SPEC
+A C string constant which is appended to the value of
+@code{LINK_SPEC}. @code{LIBC_LINK_SPEC} is intended to depend upon the
+C library in use.
+
+Do not define this macro if it does not need to do anything.
+@end defmac
+
@defmac LIB_SPEC
Another C string constant used much like @code{LINK_SPEC}. The difference
between the two is that @code{LIB_SPEC} is used at the end of the
Do not define this macro if it does not need to do anything.
@end defmac
+@defmac LIBC_CPP_SPEC
+A C string constant which is appended to the value of
+@code{CPP_SPEC}. @code{LIBC_CPP_SPEC} is intended to depend upon the
+C library in use.
+
+Do not define this macro if it does not need to do anything.
+@end defmac
+
@defmac CPLUSPLUS_CPP_SPEC
This macro is just like @code{CPP_SPEC}, but is used for C++, rather
than C@. If you do not define this macro, then the value of
Do not define this macro if it does not need to do anything.
@end defmac
+@defmac LIBC_LINK_SPEC
+A C string constant which is appended to the value of
+@code{LINK_SPEC}. @code{LIBC_LINK_SPEC} is intended to depend upon the
+C library in use.
+
+Do not define this macro if it does not need to do anything.
+@end defmac
+
@defmac LIB_SPEC
Another C string constant used much like @code{LINK_SPEC}. The difference
between the two is that @code{LIB_SPEC} is used at the end of the
#define CPP_SPEC ""
#endif
+/* libc can define LIBC_CPP_SPEC to provide extra args to the C preprocessor
+ or extra switch-translations. */
+
+#ifndef LIBC_CPP_SPEC
+#define LIBC_CPP_SPEC ""
+#endif
+
/* Operating systems can define OS_CC1_SPEC to provide extra args to cc1 and
cc1plus or extra switch-translations. The OS_CC1_SPEC is appended
to CC1_SPEC in the initialization of cc1_spec. */
#define LINK_SPEC ""
#endif
+/* libc can define LIBC_LINK_SPEC to provide extra args to the linker
+ or extra switch-translations. */
+#ifndef LIBC_LINK_SPEC
+#define LIBC_LINK_SPEC ""
+#endif
+
/* config.h can define LIB_SPEC to override the default libraries. */
#ifndef LIB_SPEC
#define LIB_SPEC "%{!shared:%{g*:-lg} %{!p:%{!pg:-lc}}%{p:-lc_p}%{pg:-lc_p}}"
static const char *asm_debug = ASM_DEBUG_SPEC;
static const char *asm_debug_option = ASM_DEBUG_OPTION_SPEC;
-static const char *cpp_spec = CPP_SPEC;
+static const char *cpp_spec = CPP_SPEC LIBC_CPP_SPEC;
static const char *cc1_spec = CC1_SPEC OS_CC1_SPEC;
static const char *cc1plus_spec = CC1PLUS_SPEC;
static const char *link_gcc_c_sequence_spec = LINK_GCC_C_SEQUENCE_SPEC;
static const char *link_ssp_spec = LINK_SSP_SPEC;
static const char *asm_spec = ASM_SPEC;
static const char *asm_final_spec = ASM_FINAL_SPEC;
-static const char *link_spec = LINK_SPEC;
+static const char *link_spec = LINK_SPEC LIBC_LINK_SPEC;
static const char *lib_spec = LIB_SPEC;
static const char *link_gomp_spec = "";
static const char *libgcc_spec = LIBGCC_SPEC;
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