From: Jiri Slaby <jslaby@suse.cz>
Subject: LTO: fix linking
References: https://sigrok.org/bugzilla/show_bug.cgi?id=1433

With LTO, the trick to collect drivers does not work. Use linker script
instead.

---
 Makefile.am             |   15 ++++-----------
 src/driver_list_start.c |   33 ---------------------------------
 src/driver_list_stop.c  |   33 ---------------------------------
 src/drivers.c           |    2 +-
 src/libdrivers.ld       |    9 +++++++++
 5 files changed, 14 insertions(+), 78 deletions(-)

--- a/Makefile.am
+++ b/Makefile.am
@@ -173,22 +173,15 @@ libsigrok_la_SOURCES += \
 	src/scale/kern.c
 
 # Hardware drivers
-noinst_LTLIBRARIES = src/libdrivers.la \
-	src/libdrivers_head.la src/libdrivers_tail.la
+noinst_LTLIBRARIES = src/libdrivers.la
 
-src/libdrivers.o: src/libdrivers.la \
-		src/libdrivers_head.la src/libdrivers_tail.la
-	$(AM_V_CCLD)$(LINK) src/libdrivers_head.la src/libdrivers.la \
-		src/libdrivers_tail.la
+src/libdrivers.o: src/libdrivers.la
+	$(AM_V_CCLD)$(LINK) src/libdrivers.la
 src/libdrivers.lo: src/libdrivers.o
 	$(AM_V_GEN)echo "# Generated by libtool" > $@
 	$(AM_V_at)echo "pic_object='libdrivers.o'" >> $@
 	$(AM_V_at)echo "non_pic_object='libdrivers.o'" >> $@
 
-src_libdrivers_head_la_SOURCES = src/driver_list_start.c
-
-src_libdrivers_tail_la_SOURCES = src/driver_list_stop.c
-
 src_libdrivers_la_SOURCES = src/drivers.c
 
 if HW_AGILENT_DMM
@@ -604,7 +597,7 @@ src_libdrivers_la_SOURCES += \
 endif
 
 libsigrok_la_LIBADD = src/libdrivers.lo $(SR_EXTRA_LIBS) $(LIBSIGROK_LIBS)
-libsigrok_la_LDFLAGS = -version-info $(SR_LIB_VERSION) -no-undefined
+libsigrok_la_LDFLAGS = -version-info $(SR_LIB_VERSION) -no-undefined -Wc,-T -Wc,src/libdrivers.ld
 
 library_includedir = $(includedir)/libsigrok
 library_include_HEADERS = \
--- a/src/driver_list_start.c
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * This file is part of the libsigrok project.
- *
- * Copyright (C) 2017 Marcus Comstedt <marcus@mc.pp.se>
- *
- * This program 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 of the License, or
- * (at your option) any later version.
- *
- * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <config.h>
-#include <glib.h>
-#include <libsigrok/libsigrok.h>
-#include "libsigrok-internal.h"
-
-/*
- * This marks the start of the driver list. This file must be linked
- * before any actual drivers.
- */
-
-SR_PRIV const struct sr_dev_driver *sr_driver_list__start[]
-	__attribute__((section (SR_DRIVER_LIST_SECTION),
-		       used, aligned(sizeof(struct sr_dev_driver *))))
-  = { NULL /* Dummy item, as zero length arrays are not allowed by C99 */ };
--- a/src/driver_list_stop.c
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * This file is part of the libsigrok project.
- *
- * Copyright (C) 2017 Marcus Comstedt <marcus@mc.pp.se>
- *
- * This program 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 of the License, or
- * (at your option) any later version.
- *
- * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <config.h>
-#include <glib.h>
-#include <libsigrok/libsigrok.h>
-#include "libsigrok-internal.h"
-
-/*
- * This marks the end of the driver list. This file must be linked
- * after any actual drivers.
- */
-
-SR_PRIV const struct sr_dev_driver *sr_driver_list__stop[]
-	__attribute__((section (SR_DRIVER_LIST_SECTION),
-		       used, aligned(sizeof(struct sr_dev_driver *))))
-  = { NULL /* Dummy item, as zero length arrays are not allowed by C99 */ };
--- a/src/drivers.c
+++ b/src/drivers.c
@@ -45,7 +45,7 @@ SR_API void sr_drivers_init(struct sr_co
 
 	array = g_array_new(TRUE, FALSE, sizeof(struct sr_dev_driver *));
 #ifdef HAVE_DRIVERS
-	for (const struct sr_dev_driver **drivers = sr_driver_list__start + 1;
+	for (const struct sr_dev_driver **drivers = sr_driver_list__start;
 	     drivers < sr_driver_list__stop; drivers++)
 		g_array_append_val(array, *drivers);
 #endif
--- /dev/null
+++ b/src/libdrivers.ld
@@ -0,0 +1,9 @@
+SECTIONS
+{
+	__sr_driver_list : {
+		sr_driver_list__start = .;
+		*(__sr_driver_list)
+		sr_driver_list__stop = .;
+	}
+}
+INSERT AFTER .data;