From 052ed480a62812eddf517b1f233aaab629b8deb6 Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Wed, 14 Dec 2022 09:31:28 +0100
Subject: [PATCH] platform: fix "-Wcast-align" warning on i686 in
 nmp_object_ref()

With gcc-12.2.1-4.fc37 on i686 we get:

  ./src/libnm-platform/nmp-object.h: In function 'nmp_object_ref':
  ./src/libnm-platform/nmp-object.h:626:12: error: cast increases required alignment of target type [-Werror=cast-align]
    626 |     return (const NMPObject *) nm_dedup_multi_obj_ref((const NMDedupMultiObj *) obj);
        |            ^
  cc1: all warnings being treated as errors

Work around that be increasing the alignment of NMDedupMultiObj.
It has no downsides, because we usually put a NMDedupMultiObj in heap
allocated memory, which is already suitably aligned. Or we put it on
the stack, where wasting a few bytes for the alignment doesn't matter.
We basically never embed NMDedupMultiObj in an array where the increase
of alignment would waste additional space.
---
 src/libnm-glib-aux/nm-dedup-multi.h | 4 +++-
 src/libnm-platform/nmp-object.h     | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/libnm-glib-aux/nm-dedup-multi.h b/src/libnm-glib-aux/nm-dedup-multi.h
index 09b4a11e63..87a2b81583 100644
--- a/src/libnm-glib-aux/nm-dedup-multi.h
+++ b/src/libnm-glib-aux/nm-dedup-multi.h
@@ -37,6 +37,8 @@ typedef enum _NMDedupMultiIdxMode {
 
 /*****************************************************************************/
 
+#define _NMDedupMultiObj_Align (MAX(_nm_alignof(void *), _nm_alignof(gint64)))
+
 struct _NMDedupMultiObj {
     union {
         NMObjBaseInst               parent;
@@ -44,7 +46,7 @@ struct _NMDedupMultiObj {
     };
     NMDedupMultiIndex *_multi_idx;
     guint              _ref_count;
-};
+} _nm_align(_NMDedupMultiObj_Align);
 
 struct _NMDedupMultiObjClass {
     NMObjBaseClass parent;
diff --git a/src/libnm-platform/nmp-object.h b/src/libnm-platform/nmp-object.h
index 5f98deeda4..4901ebcba3 100644
--- a/src/libnm-platform/nmp-object.h
+++ b/src/libnm-platform/nmp-object.h
@@ -427,7 +427,7 @@ struct _NMPObject {
         NMPlatformMptcpAddr mptcp_addr;
         NMPObjectMptcpAddr  _mptcp_addr;
     };
-};
+} _nm_alignas(NMDedupMultiObj);
 
 /*****************************************************************************/