Re: [Qemu-devel] [PATCH] bswap: Don't rely on HOST_LONG_BITS

[Stefan Weil]

Am 30.01.2013 22:04, schrieb Stefan Weil:

Am 30.01.2013 21:55, schrieb Richard Henderson:

This is not always defined in all places qemu/bswap.h is used.
If we include qemu-common.h to get it, we create an include loop.
This resolves a build problem on any big-endian host like ppc64.

Signed-off-by: Richard Henderson<r...@twiddle.net>
---
  include/qemu/bswap.h | 12 ++++++++++--
  1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h
index e6d4798..d3af35d 100644
--- a/include/qemu/bswap.h
+++ b/include/qemu/bswap.h
@@ -2,8 +2,8 @@
  #define BSWAP_H

  #include "config-host.h"
-
  #include<inttypes.h>
+#include<limits.h>
  #include "fpu/softfloat.h"

  #ifdef CONFIG_MACHINE_BSWAP_H

@@ -458,7 +458,15 @@ static inline void cpu_to_32wu(uint32_t *p, uint32_t v)

  static inline unsigned long leul_to_cpu(unsigned long v)
  {
-    return le_bswap(v, HOST_LONG_BITS);
+    /* In order to break an include loop between here and
+       qemu-common.h, don't rely on HOST_LONG_BITS.  */
+#if ULONG_MAX == UINT32_MAX
+    return le_bswap(v, 32);
+#elif ULONG_MAX == UINT64_MAX
+    return le_bswap(v, 64);
+#else
+# error Unknown sizeof long
+#endif
  }

  #undef le_bswap

That would be wrong for 64 bit MinGW-w64 because
HOST_LONG_BITS is _not_ the bit size of a long value.

See qemu-common.h for the correct definition.

Regards
Stefan W.

Could you please try whether this patch fixes the build problems:


From 4dd39af7a3e493669977ec6f50e91bf649b5727f Mon Sep 17 00:00:00 2001
From: Stefan Weil <s...@weilnetz.de>
Date: Wed, 30 Jan 2013 22:52:12 +0100
Subject: [PATCH] Fix build problems for big endian hosts

Make sure that HOST_LONG_BITS is always defined when qemu/bswap.h
is included.

Signed-off-by: Stefan Weil <s...@weilnetz.de>
---
 fsdev/virtio-9p-marshal.c |   12 +-----------
 hw/spapr_nvram.c          |    2 ++
 include/qemu/bswap.h      |    4 ++++
 3 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/fsdev/virtio-9p-marshal.c b/fsdev/virtio-9p-marshal.c
index 20f308b..4e634df 100644
--- a/fsdev/virtio-9p-marshal.c
+++ b/fsdev/virtio-9p-marshal.c
@@ -11,20 +11,10 @@
  *
  */

-#include <glib.h>
 #include <glib/gprintf.h>
-#include <sys/types.h>
-#include <dirent.h>
-#include <sys/time.h>
-#include <utime.h>
-#include <sys/uio.h>
-#include <string.h>
-#include <stdint.h>
-#include <errno.h>

-#include "qemu/compiler.h"
+#include "qemu-common.h"
 #include "virtio-9p-marshal.h"
-#include "qemu/bswap.h"

 void v9fs_string_free(V9fsString *str)
 {
diff --git a/hw/spapr_nvram.c b/hw/spapr_nvram.c
index 680cdba..2960b15 100644
--- a/hw/spapr_nvram.c
+++ b/hw/spapr_nvram.c
@@ -22,6 +22,8 @@
  * THE SOFTWARE.
  */

+#include "qemu-common.h"
+
 #include <libfdt.h>

 #include "sysemu/device_tree.h"
diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h
index e6d4798..07dadc2 100644
--- a/include/qemu/bswap.h
+++ b/include/qemu/bswap.h
@@ -13,6 +13,10 @@
 #elif defined(CONFIG_BYTESWAP_H)
 # include <byteswap.h>

+#if !defined(HOST_LONG_BITS)
+# error needs HOST_LONG_BITS
+#endif
+
 static inline uint16_t bswap16(uint16_t x)
 {
     return bswap_16(x);
--
1.7.10.4