From d13adebe1ab7c6c7f6c7d2633851a2f47a596556 Mon Sep 17 00:00:00 2001
From: Simon Tatham <anakin@pobox.com>
Date: Thu, 24 Dec 2020 09:34:13 +0000
Subject: [PATCH] uxutils.c: move some definitions into a header file.

If the autoconf/ifdef system ends up taking the trivial branch through
all the Arm-architecture ifdefs, then we define the always-fail
version of getauxval as a 'static inline' function, and then (because
none of our desired HWCAP_FOO values is defined at all) never call it.
This leads to a compiler warning because we defined a static function
and never called it - i.e. at the default -Werror, a build failure.

Of course it's perfectly sensible to define a static inline function
that never gets called! Header files do it all the time, and nobody is
expected to ensure that if they include a header file then they take
care to refer to every static inline function it defines.

But if the definition is in the _source_ file rather than a header
file, then clang (in particular on macOS) will give a warning. So the
easy solution is to move the inline definitions of getauxval into a
header file, which suppresses the warning without requiring me to faff
about with further ifdefs to make the definitions conditional on at
least one use.
---
 unix/uxutils.c | 30 ++----------------------------
 unix/uxutils.h | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 28 deletions(-)
 create mode 100644 unix/uxutils.h

diff --git a/unix/uxutils.c b/unix/uxutils.c
index 467e5bcc..4a63ac86 100644
--- a/unix/uxutils.c
+++ b/unix/uxutils.c
@@ -1,36 +1,10 @@
 #include "putty.h"
 #include "ssh.h"
 
+#include "uxutils.h"
+
 #if defined __arm__ || defined __aarch64__
 
-#ifdef HAVE_SYS_TYPES_H
-#include <sys/types.h>
-#endif
-
-#ifdef HAVE_SYS_AUXV_H
-#include <sys/auxv.h>
-#endif
-
-#ifdef HAVE_ASM_HWCAP_H
-#include <asm/hwcap.h>
-#endif
-
-#if defined HAVE_GETAUXVAL
-/* No code needed: getauxval has just the API we want already */
-#elif defined HAVE_ELF_AUX_INFO
-/* Implement the simple getauxval API in terms of FreeBSD elf_aux_info */
-static inline u_long getauxval(int which)
-{
-    u_long toret;
-    if (elf_aux_info(which, &toret, sizeof(toret)) != 0)
-        return 0;                      /* elf_aux_info didn't work */
-    return toret;
-}
-#else
-/* Implement a stub getauxval which returns no capabilities */
-static inline u_long getauxval(int which) { return 0; }
-#endif
-
 bool platform_aes_hw_available(void)
 {
 #if defined HWCAP_AES
diff --git a/unix/uxutils.h b/unix/uxutils.h
new file mode 100644
index 00000000..4e8dc808
--- /dev/null
+++ b/unix/uxutils.h
@@ -0,0 +1,45 @@
+/*
+ * uxutils.h: header included only by uxutils.c.
+ *
+ * The only reason this is a header file instead of a source file is
+ * so that I can define 'static inline' functions which may or may not
+ * be used, without provoking a compiler warning when I turn out not
+ * to use them in the subsequent source file.
+ */
+
+#ifndef PUTTY_UXUTILS_H
+#define PUTTY_UXUTILS_H
+
+#if defined __arm__ || defined __aarch64__
+
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
+#ifdef HAVE_SYS_AUXV_H
+#include <sys/auxv.h>
+#endif
+
+#ifdef HAVE_ASM_HWCAP_H
+#include <asm/hwcap.h>
+#endif
+
+#if defined HAVE_GETAUXVAL
+/* No code needed: getauxval has just the API we want already */
+#elif defined HAVE_ELF_AUX_INFO
+/* Implement the simple getauxval API in terms of FreeBSD elf_aux_info */
+static inline u_long getauxval(int which)
+{
+    u_long toret;
+    if (elf_aux_info(which, &toret, sizeof(toret)) != 0)
+        return 0;                      /* elf_aux_info didn't work */
+    return toret;
+}
+#else
+/* Implement a stub getauxval which returns no capabilities */
+static inline u_long getauxval(int which) { return 0; }
+#endif
+
+#endif /* defined __arm__ || defined __aarch64__ */
+
+#endif /* PUTTY_UXUTILS_H */