From 3decd3b1f0cbb3a035f72e9eade42279d0507b89 Mon Sep 17 00:00:00 2001
From: Gerhard Sittig <gerhard.sittig@gmx.net>
Date: Tue, 3 Nov 2020 18:25:18 +0100
Subject: [PATCH] driver_list: unbreak list of builtin drivers for LTO
 configurations

Check for the availability of the "no_reorder" linker attribute, which
keeps the list of builtin drivers in shape on LTO enabled build setups.
Keep backwards compatibility for platforms which lack support for the
"no_reorder" attribute. Phrase the implementation such that other
keywords as well as user provided external specs are possible.

This resolves bug #1433.

Submitted-By: Ivan Mironov <mironov.ivan@gmail.com>
---
 src/driver_list_start.c  |  1 +
 src/driver_list_stop.c   |  1 +
 src/libsigrok-internal.h | 10 ++++++++++
 3 files changed, 12 insertions(+)

diff --git a/src/driver_list_start.c b/src/driver_list_start.c
index 7b6c7755..535e3312 100644
--- a/src/driver_list_start.c
+++ b/src/driver_list_start.c
@@ -28,6 +28,7 @@
  */
 
 SR_PRIV const struct sr_dev_driver *sr_driver_list__start[]
+	SR_DRIVER_LIST_NOREORDER
 	__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 */ };
diff --git a/src/driver_list_stop.c b/src/driver_list_stop.c
index ff2c51de..eefda055 100644
--- a/src/driver_list_stop.c
+++ b/src/driver_list_stop.c
@@ -28,6 +28,7 @@
  */
 
 SR_PRIV const struct sr_dev_driver *sr_driver_list__stop[]
+	SR_DRIVER_LIST_NOREORDER
 	__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 */ };
diff --git a/src/libsigrok-internal.h b/src/libsigrok-internal.h
index 98d1631e..19fcccfd 100644
--- a/src/libsigrok-internal.h
+++ b/src/libsigrok-internal.h
@@ -967,6 +967,15 @@ static inline void write_dblle_inc(uint8_t **p, double x)
 #define SR_DRIVER_LIST_SECTION "__sr_driver_list"
 #endif
 
+#if !defined SR_DRIVER_LIST_NOREORDER && defined __has_attribute
+#if __has_attribute(no_reorder)
+#define SR_DRIVER_LIST_NOREORDER __attribute__((no_reorder))
+#endif
+#endif
+#if !defined SR_DRIVER_LIST_NOREORDER
+#define SR_DRIVER_LIST_NOREORDER /* EMPTY */
+#endif
+
 /**
  * Register a list of hardware drivers.
  *
@@ -996,6 +1005,7 @@ static inline void write_dblle_inc(uint8_t **p, double x)
  */
 #define SR_REGISTER_DEV_DRIVER_LIST(name, ...) \
 	static const struct sr_dev_driver *name[] \
+		SR_DRIVER_LIST_NOREORDER \
 		__attribute__((section (SR_DRIVER_LIST_SECTION), used, \
 			aligned(sizeof(struct sr_dev_driver *)))) \
 		= { \
-- 
2.26.2