From 12acb42f2e6317a530fa01b5cf55a199231bfdce Mon Sep 17 00:00:00 2001
From: Thomas Huth <thuth@redhat.com>
Date: Sun, 2 May 2021 13:49:20 +0200
Subject: [PATCH 31/39] pc-bios/s390-ccw: Silence warning from Clang by marking
 panic() as noreturn
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RH-Author: Jon Maloy <jmaloy@redhat.com>
RH-MergeRequest: 24: v7:  Add support for building qemu-kvm with clang and safe-stack
RH-Commit: [4/11] 806b776bf01b733e04664534641cf89d1cb48f1b (jmaloy/qemu-kvm-centos-jon)
RH-Bugzilla: 1939509 1940132
RH-Acked-by: Danilo Cesar Lemes de Paula <ddepaula@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Cornelia Huck <cohuck@redhat.com>

When compiling the s390-ccw bios with Clang, the compiler emits a warning:

 pc-bios/s390-ccw/main.c:210:5: warning: variable 'found' is used uninitialized
  whenever switch default is taken [-Wsometimes-uninitialized]
     default:
     ^~~~~~~
 pc-bios/s390-ccw/main.c:214:16: note: uninitialized use occurs here
     IPL_assert(found, "Boot device not found\n");
                ^~~~~

It's a false positive, it only happens because Clang is not smart enough
to see that the panic() function in the "default:" case can never return.

Anyway, let's explicitely mark panic() with "noreturn" to shut up the
warning.

Message-Id: <20210502174836.838816-2-thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit 679196a646c91b8ce9a97b0aa81ffb3776cf8046)
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 pc-bios/s390-ccw/s390-ccw.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
index 6cd92669e9..79db69ff54 100644
--- a/pc-bios/s390-ccw/s390-ccw.h
+++ b/pc-bios/s390-ccw/s390-ccw.h
@@ -89,6 +89,7 @@ bool menu_is_enabled_enum(void);
 
 #define MAX_BOOT_ENTRIES  31
 
+__attribute__ ((__noreturn__))
 static inline void panic(const char *string)
 {
     sclp_print(string);
-- 
2.27.0