Match *-picolibc-* and select picolibc as the default C library, plus
continuing to use the newlib-based logic for other configuration
items.
Add custom spec file fragments for use with picolibc:
* '--oslib='. Allows targets to insert an OS library after the C
library in the LIB_PATH spec file fragment. This library maps a few
POSIX APIs used by picolibc to underlying system capabilities.
* '--crt0='. Allows targets to use an alternate crt0 in place of the
usual one as provided by Picolibc.
* '--printf='. Allows targets to customize the version of printf linked
from the C library.
Signed-off-by: Keith Packard <kei...@keithp.com>
---
gcc/config.gcc | 9 ++++++
gcc/config/picolibc-spec.h | 57 ++++++++++++++++++++++++++++++++++++
gcc/config/picolibc.opt | 47 +++++++++++++++++++++++++++++
gcc/config/picolibc.opt.urls | 2 ++
gcc/gcc.cc | 17 +++++++++--
5 files changed, 130 insertions(+), 2 deletions(-)
create mode 100644 gcc/config/picolibc-spec.h
create mode 100644 gcc/config/picolibc.opt
create mode 100644 gcc/config/picolibc.opt.urls
diff --git a/gcc/config.gcc b/gcc/config.gcc
index 1e386a469e0..b20545da649 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -1161,6 +1161,15 @@ case ${target} in
;;
esac
;;
+*-picolibc-*)
+ # picolibc provides __cxa_atexit
+ default_use_cxa_atexit=yes
+ # picolibc provides stdint.h
+ use_gcc_stdint=none
+ tm_file="${tm_file} picolibc-spec.h"
+ extra_options="${extra_options} picolibc.opt"
+ ;;
+
*-*-elf|arc*-*-elf*)
# Assume that newlib is being used and so __cxa_atexit is provided.
default_use_cxa_atexit=yes
diff --git a/gcc/config/picolibc-spec.h b/gcc/config/picolibc-spec.h
new file mode 100644
index 00000000000..40a55c056f4
--- /dev/null
+++ b/gcc/config/picolibc-spec.h
@@ -0,0 +1,57 @@
+/* Configuration common to all targets running Picolibc.
+ Copyright (C) 2023 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
diff --git a/gcc/config/picolibc.opt b/gcc/config/picolibc.opt
new file mode 100644
index 00000000000..c5192fd6378
--- /dev/null
+++ b/gcc/config/picolibc.opt
@@ -0,0 +1,47 @@
+; Processor-independent options for picolibc.
+;
+; Copyright (C) 2022 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.
diff --git a/gcc/config/picolibc.opt.urls b/gcc/config/picolibc.opt.urls
new file mode 100644
index 00000000000..b3a57d15a39
--- /dev/null
+++ b/gcc/config/picolibc.opt.urls
@@ -0,0 +1,2 @@
+; Autogenerated by regenerate-opt-urls.py from gcc/config/picolibc.opt and
generated HTML
+
diff --git a/gcc/gcc.cc b/gcc/gcc.cc
index 4fd87f2c4a1..ddf5b6e5b5b 100644
--- a/gcc/gcc.cc
+++ b/gcc/gcc.cc
@@ -726,6 +726,13 @@ proper position among the other output files. */
#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. */
@@ -751,6 +758,12 @@ proper position among the other output files. */
#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}}"
@@ -1204,14 +1217,14 @@ proper position among the other output files. */
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;
--
2.49.0
