[PATCH v4 1/2] libgloss: merge pru into top-level Makefile

[PATCH v4 1/2] libgloss: merge pru into top-level Makefile

[Dimitar Dimitrov]

Avoid a recursive make to speed things up a bit.  This change was
inspired by the recent similar patch for c6x:
https://sourceware.org/pipermail/newlib/2023/020869.html

While at it, fork crt0-minrt.S into a separate source file instead of
relying on a predefined macro to generate two different object files.
This improves clarity, simplifies the build rules, and would allow
further optimization in crt0-minrt.S to be implemented more cleanly.

Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>
---
Changes since v3:
 - Rebased.

Changes since v2:
 - Rearrange Makefile.inc code chunks.
 - Whitespace fix.

Changes since v1:
 - Retained copyright in pru/Makefile.inc.
 - Addec crt0*.s to libobjs_a_SOURCES.
 - Rebased.

 libgloss/Makefile.am      |   3 +
 libgloss/configure.ac     |   7 +-
 libgloss/pru/Makefile.in  | 145 --------------------------------------
 libgloss/pru/Makefile.inc |  48 +++++++++++++
 libgloss/pru/crt0-minrt.S |  59 ++++++++++++++++
 libgloss/pru/crt0.S       |   6 --
 6 files changed, 113 insertions(+), 155 deletions(-)
 delete mode 100644 libgloss/pru/Makefile.in
 create mode 100644 libgloss/pru/Makefile.inc
 create mode 100644 libgloss/pru/crt0-minrt.S

diff --git a/libgloss/Makefile.am b/libgloss/Makefile.am
index 333ff846a..084d433d3 100644
--- a/libgloss/Makefile.am
+++ b/libgloss/Makefile.am
@@ -155,6 +155,9 @@ endif
 if CONFIG_OR1K
 include or1k/Makefile.inc
 endif
+if CONFIG_PRU
+include pru/Makefile.inc
+endif
 if CONFIG_RISCV
 include riscv/Makefile.inc
 endif
diff --git a/libgloss/configure.ac b/libgloss/configure.ac
index 55f4261d1..79457cc79 100644
--- a/libgloss/configure.ac
+++ b/libgloss/configure.ac
@@ -207,8 +207,7 @@ case "${target}" in
 	config_or1k=true
 	;;
   pru-*-*)
-	AC_CONFIG_FILES([pru/Makefile])
-	subdirs="$subdirs pru"
+	config_pru=true
 	;;
   nios2-*-*)
 	config_nios2=true
@@ -222,8 +221,8 @@ m4_foreach_w([SUBDIR], [
   aarch64 arc arm bfin csky d30v epiphany fr30 frv ft32 i386 i960 iq2000
   libnosys lm32
   m32r mcore microblaze mn10200 mn10300 moxie msp430
-  nds32 nios2 or1k riscv rl78 rx sparc sparc_leon tic6x v850 visium wince
-  xstormy16 xtensa
+  nds32 nios2 or1k pru riscv rl78 rx sparc sparc_leon tic6x v850 visium
+  wince xstormy16 xtensa
 ], [dnl
   AM_CONDITIONAL([CONFIG_]m4_toupper(SUBDIR), [test x$config_]SUBDIR = xtrue)
 ])
diff --git a/libgloss/pru/Makefile.in b/libgloss/pru/Makefile.in
deleted file mode 100644
index fc5905a5e..000000000
--- a/libgloss/pru/Makefile.in
+++ /dev/null
@@ -1,145 +0,0 @@
-# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
-#
-# Copyright 2018-2019 Dimitar Dimitrov <dimitar@dinux.eu>
-# All rights reserved.
-#
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions
-# are met:
-# 1. Redistributions of source code must retain the above copyright
-#    notice, this list of conditions and the following disclaimer.
-# 2. Redistributions in binary form must reproduce the above copyright
-#    notice, this list of conditions and the following disclaimer in the
-#    documentation and/or other materials provided with the distribution.
-#
-# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
-# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
-# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
-# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
-# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
-# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
-# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-VPATH = @srcdir@ @srcdir@/..
-
-srcdir = @srcdir@
-objdir = .
-srcroot = $(srcdir)/../..
-objroot = $(objdir)/../..
-
-prefix = @prefix@
-exec_prefix = @exec_prefix@
-
-host_alias = @host_alias@
-target_alias = @target_alias@
-
-bindir = @bindir@
-libdir = @libdir@
-includedir = @includedir@
-tooldir = $(exec_prefix)/$(target_alias)
-
-# Multilib support variables.
-# TOP is used instead of MULTI{BUILD,SRC}TOP.
-MULTIDIRS =
-MULTISUBDIR =
-
-SHELL =	/bin/sh
-
-mkinstalldirs = $(SHELL) $(srcroot)/mkinstalldirs
-
-CC = @CC@
-
-AS = @AS@
-
-AR = @AR@
-
-LD = @LD@
-
-RANLIB = @RANLIB@
-
-OBJDUMP = `t='$(program_transform_name)'; echo objdump | sed -e $$t`
-OBJCOPY = `t='$(program_transform_name)'; echo objcopy | sed -e $$t`
-
-# object files needed
-OBJS = \
-	do_global_dtors.o gettimeofday.o \
-	isatty.o putnum.o raise.o \
-	inbyte.o outbyte.o sbrk.o stat.o syscalls.o \
-	do_global_dtors.o
-
-# Object files specific to particular targets.
-EVALOBJS = ${OBJS}
-
-CRTOBJS = crt0.o crt0-minrt.o
-OUTPUTS = libgloss.a $(CRTOBJS)
-
-INCLUDES = -I$(srcdir)/..
-
-# Note that when building the library, ${MULTILIB} is not the way multilib
-# options are passed; they're passed in $(CFLAGS).
-CFLAGS_FOR_TARGET = ${MULTILIB} ${INCLUDES}
-LDFLAGS_FOR_TARGET = ${MULTILIB}
-
-.c.o:
-	$(CC) $(CFLAGS_FOR_TARGET) -Os $(INCLUDES) -c $(CFLAGS) $<
-
-.C.o:
-	$(CC) $(CFLAGS_FOR_TARGET) -Os $(INCLUDES) -c $(CFLAGS) $<
-.s.o:
-	$(AS) $(ASFLAGS_FOR_TARGET) $(ASFLAGS) -o $*.o $<
-
-#
-# GCC knows to run the preprocessor on .S files before it assembles them.
-#
-.S.o:
-	$(CC) $(CFLAGS_FOR_TARGET) $(INCLUDES) $(CFLAGS) -c $<
-
-all: ${OUTPUTS}
-
-#
-# here's where we build the library for each target
-#
-
-libgloss.a: $(EVALOBJS)
-	${AR} ${ARFLAGS} $@ $(EVALOBJS)
-	${RANLIB} $@
-
-# C Runtime Library startup code.
-crt0.o: $(srcdir)/crt0.S
-	$(CC) $(CFLAGS_FOR_TARGET) $(INCLUDES) $(CFLAGS) $< -c -o $@
-
-crt0-minrt.o: $(srcdir)/crt0.S
-	$(CC) $(CFLAGS_FOR_TARGET) $(INCLUDES) $(CFLAGS) -DMINRT $< -c -o $@
-
-doc:
-
-clean mostlyclean:
-	rm -f $(OUTPUTS) *.i *~ *.o *-test *.srec *.dis *.map *.x
-
-distclean maintainer-clean realclean: clean
-	rm -f Makefile $(OUTPUTS)
-
-.PHONY: install info install-info clean-info
-install: $(OUTPUTS)
-	for outputs in ${OUTPUTS}; do\
-	 ${INSTALL_DATA} $${outputs} ${DESTDIR}${tooldir}/lib${MULTISUBDIR}/$${outputs}; \
-	done
-	for s in $(SCRIPTS); do \
-	  b=`basename $$s`; \
-	  ${INSTALL_DATA} $$s ${DESTDIR}${tooldir}/lib${MULTISUBDIR}/$$b ;\
-	done
-	${mkinstalldirs} ${DESTDIR}${tooldir}/lib${MULTISUBDIR}/device-specs; \
-	for s in ${srcdir}/device-specs/*; do \
-	  b=`basename $$s`; \
-	  $(INSTALL_DATA) $$s $(DESTDIR)$(tooldir)/lib${MULTISUBDIR}/device-specs/$$b ;\
-	done
-
-info:
-install-info:
-clean-info:
-
-Makefile: $(srcdir)/Makefile.in ../config.status
-	cd .. && $(SHELL) config.status
diff --git a/libgloss/pru/Makefile.inc b/libgloss/pru/Makefile.inc
new file mode 100644
index 000000000..f8408b28f
--- /dev/null
+++ b/libgloss/pru/Makefile.inc
@@ -0,0 +1,48 @@
+## SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+##
+## Copyright 2018-2024 Dimitar Dimitrov <dimitar@dinux.eu>
+## All rights reserved.
+##
+## Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions
+## are met:
+## 1. Redistributions of source code must retain the above copyright
+##    notice, this list of conditions and the following disclaimer.
+## 2. Redistributions in binary form must reproduce the above copyright
+##    notice, this list of conditions and the following disclaimer in the
+##    documentation and/or other materials provided with the distribution.
+##
+## THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+## IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+## OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+## IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+## INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+## NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+## THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+multilibtool_DATA += \
+	%D%/crt0.o \
+	%D%/crt0-minrt.o
+
+libobjs_a_SOURCES += \
+	%D%/crt0.S \
+	%D%/crt0-minrt.S
+
+multilibtool_LIBRARIES += %D%/libgloss.a
+%C%_libgloss_a_SOURCES = \
+	%D%/do_global_dtors.c \
+	%D%/gettimeofday.c \
+	%D%/isatty.c \
+	%D%/putnum.c \
+	%D%/raise.c \
+	%D%/inbyte.c \
+	%D%/outbyte.c \
+	%D%/sbrk.c \
+	%D%/stat.c \
+	%D%/syscalls.S
+
+pru_devicespecsdir = $(multilibtooldir)/device-specs
+pru_devicespecs_DATA = %D%/device-specs/sim
diff --git a/libgloss/pru/crt0-minrt.S b/libgloss/pru/crt0-minrt.S
new file mode 100644
index 000000000..60647d372
--- /dev/null
+++ b/libgloss/pru/crt0-minrt.S
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * crt0-minrt.S -- Minimal PRU startup code
+ *
+ * Copyright (c) 2024 Dimitar Dimitrov <dimitar@dinux.eu>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "newlib.h"
+
+	.extern	main
+
+	.text
+	.section .init0, "x"
+	.global	_start
+_start:
+	/* Initialize stack pointer. */
+	ldi32	sp, _stack_top
+
+	/* DATA and BSS are handled by the loader, so nothing to do here. */
+
+	/* Just in case main() tries to access argc, argv[] and envp. */
+	zero	r14, 3 * 4
+
+	/* Call main. */
+	call	main
+
+	/* We should never reach here. */
+_crt_exit:
+	halt
+	jmp	_crt_exit
+
+	/* PRU obviously has no shared libraries, but dso_handle
+	   helps to achieve better GCC test coverage. Besides,
+	   it should be free with minrt. */
+	.section .data
+	.global __dso_handle
+	.weak __dso_handle
+__dso_handle:
+	.long	0
diff --git a/libgloss/pru/crt0.S b/libgloss/pru/crt0.S
index b3f0d53a9..ad31cc9cc 100644
--- a/libgloss/pru/crt0.S
+++ b/libgloss/pru/crt0.S
@@ -39,7 +39,6 @@ _start:
 
 	/* DATA and BSS are handled by the loader, so nothing to do here. */
 
-#if !defined(MINRT)
 	.extern _do_global_dtors
 	/* Ensure destructors get called.  Call is per GNU ABI (i.e. 32-bit
 	   function pointers).  But it is also compatible with the TI ABI
@@ -60,27 +59,22 @@ ctors_loop:
 	add	r5, r5, 2
 	jmp	ctors_loop
 ctors_done:
-#endif
 
 	/* Just in case main() tries to access argc, argv[] and envp. */
 	zero	r14, 3 * 4
 
-#if !defined(MINRT)
 	.weak __c_args__
 	ldi32	r5, __c_args__
 	qbeq	__skip_c_args, r5, 0
 	lbbo	r14, r5, 0, 4	/* argc */
 	add	r15, r5, 4	/* argv */
 __skip_c_args:
-#endif
 
 	/* Call main */
 	call	main
 
-#if !defined(MINRT)
 	/* Call exit */
 	call	exit
-#endif
 
 	/* We should never reach here. */
 _crt_exit:
-- 
2.43.0

[PATCH v4 2/2] libgloss: pru: Trim crt0-minrt.o

[Dimitar Dimitrov]

Strip a few more instructions from crt0-minrt.S:
  - Remove "halt" and rely on the infinite loop after main()'s return.
  - Remove main()'s argc and argv argument initialization.  Host loader
    does not set them, and typical firmware does not use them, either.
  - Remove the __dso_handle symbol.

This should be safe because the default crt0.S is fully standards
compliant.  Whereas crt0-minrt.S has been documented from the beginning
to intentionally miss features in order to reduce firmware size, while
still enabling typical PRU firmware to operate.

Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>
---
 libgloss/pru/crt0-minrt.S | 15 +--------------
 1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/libgloss/pru/crt0-minrt.S b/libgloss/pru/crt0-minrt.S
index 60647d372..fa5e80af4 100644
--- a/libgloss/pru/crt0-minrt.S
+++ b/libgloss/pru/crt0-minrt.S
@@ -38,22 +38,9 @@ _start:
 
 	/* DATA and BSS are handled by the loader, so nothing to do here. */
 
-	/* Just in case main() tries to access argc, argv[] and envp. */
-	zero	r14, 3 * 4
-
-	/* Call main. */
+	/* Call main. Assume argc and argv are not used with -minrt! */
 	call	main
 
 	/* We should never reach here. */
 _crt_exit:
-	halt
 	jmp	_crt_exit
-
-	/* PRU obviously has no shared libraries, but dso_handle
-	   helps to achieve better GCC test coverage. Besides,
-	   it should be free with minrt. */
-	.section .data
-	.global __dso_handle
-	.weak __dso_handle
-__dso_handle:
-	.long	0
-- 
2.43.0

Re: [PATCH v4 1/2] libgloss: merge pru into top-level Makefile

[Corinna Vinschen]

On Jan 22 18:11, Dimitar Dimitrov wrote:
> Avoid a recursive make to speed things up a bit.  This change was
> inspired by the recent similar patch for c6x:
> https://sourceware.org/pipermail/newlib/2023/020869.html
> 
> While at it, fork crt0-minrt.S into a separate source file instead of
> relying on a predefined macro to generate two different object files.
> This improves clarity, simplifies the build rules, and would allow
> further optimization in crt0-minrt.S to be implemented more cleanly.
> 
> Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>
> ---
> Changes since v3:
>  - Rebased.
> 
> Changes since v2:
>  - Rearrange Makefile.inc code chunks.
>  - Whitespace fix.
> 
> Changes since v1:
>  - Retained copyright in pru/Makefile.inc.
>  - Addec crt0*.s to libobjs_a_SOURCES.
>  - Rebased.
> 
>  libgloss/Makefile.am      |   3 +
>  libgloss/configure.ac     |   7 +-
>  libgloss/pru/Makefile.in  | 145 --------------------------------------
>  libgloss/pru/Makefile.inc |  48 +++++++++++++
>  libgloss/pru/crt0-minrt.S |  59 ++++++++++++++++
>  libgloss/pru/crt0.S       |   6 --
>  6 files changed, 113 insertions(+), 155 deletions(-)
>  delete mode 100644 libgloss/pru/Makefile.in
>  create mode 100644 libgloss/pru/Makefile.inc
>  create mode 100644 libgloss/pru/crt0-minrt.S

Series pushed.

Thanks,
Corinna