Re: [PATCH v2] disas/libvixl: Protect C system header for C++ compiler

[Philippe Mathieu-Daudé]

Hi Peter, since libvixl is mostly used by the Aarch64 target,
can you take this patch via your ARM tree? (Thomas reviewed
it).

On 5/16/21 7:10 PM, Philippe Mathieu-Daudé wrote:
> When selecting an ARM target on Debian unstable, we get:
> 
>   Compiling C++ object libcommon.fa.p/disas_libvixl_vixl_utils.cc.o
>   FAILED: libcommon.fa.p/disas_libvixl_vixl_utils.cc.o
>   c++ -Ilibcommon.fa.p -I. -I.. [...] -o 
> libcommon.fa.p/disas_libvixl_vixl_utils.cc.o -c ../disas/libvixl/vixl/utils.cc
>   In file included from /home/philmd/qemu/disas/libvixl/vixl/utils.h:30,
>                    from ../disas/libvixl/vixl/utils.cc:27:
>   /usr/include/string.h:36:43: error: missing binary operator before token "("
>      36 | #if defined __cplusplus && (__GNUC_PREREQ (4, 4) \
>         |                                           ^
>   /usr/include/string.h:53:62: error: missing binary operator before token "("
>      53 | #if defined __USE_MISC || defined __USE_XOPEN || __GLIBC_USE 
> (ISOC2X)
>         |                                                              ^
>   /usr/include/string.h:165:21: error: missing binary operator before token 
> "("
>     165 |      || __GLIBC_USE (LIB_EXT2) || __GLIBC_USE (ISOC2X))
>         |                     ^
>   /usr/include/string.h:174:43: error: missing binary operator before token 
> "("
>     174 | #if defined __USE_XOPEN2K8 || __GLIBC_USE (LIB_EXT2) || __GLIBC_USE 
> (ISOC2X)
>         |                                           ^
>   /usr/include/string.h:492:19: error: missing binary operator before token 
> "("
>     492 | #if __GNUC_PREREQ (3,4)
>         |                   ^
> 
> Relevant information from the host:
> 
>   $ lsb_release -d
>   Description:    Debian GNU/Linux 11 (bullseye)
>   $ gcc --version
>   gcc (Debian 10.2.1-6) 10.2.1 20210110
>   $ dpkg -S /usr/include/string.h
>   libc6-dev: /usr/include/string.h
>   $ apt-cache show libc6-dev
>   Package: libc6-dev
>   Version: 2.31-11
> 
> Partially cherry-pick vixl commit 78973f258039f6e96 [*]:
> 
>   Refactor VIXL to use `extern` block when including C header
>   that do not have a C++ counterpart.
> 
> which is similar to commit 875df03b221 ('osdep: protect qemu/osdep.h
> with extern "C"').
> 
> [*] https://git.linaro.org/arm/vixl.git/commit/?id=78973f258039f6e96
> 
> Buglink: https://bugs.launchpad.net/qemu/+bug/1914870
> Suggested-by: Thomas Huth <thuth@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  disas/libvixl/vixl/code-buffer.h |  2 +-
>  disas/libvixl/vixl/globals.h     | 16 +++++++++-------
>  disas/libvixl/vixl/invalset.h    |  2 +-
>  disas/libvixl/vixl/platform.h    |  2 ++
>  disas/libvixl/vixl/utils.h       |  2 +-
>  disas/libvixl/vixl/utils.cc      |  2 +-
>  6 files changed, 15 insertions(+), 11 deletions(-)
> 
> diff --git a/disas/libvixl/vixl/code-buffer.h 
> b/disas/libvixl/vixl/code-buffer.h
> index f93ebb6b822..b95babbdee2 100644
> --- a/disas/libvixl/vixl/code-buffer.h
> +++ b/disas/libvixl/vixl/code-buffer.h
> @@ -27,7 +27,7 @@
>  #ifndef VIXL_CODE_BUFFER_H
>  #define VIXL_CODE_BUFFER_H
>  
> -#include <string.h>
> +#include <cstring>
>  #include "vixl/globals.h"
>  
>  namespace vixl {
> diff --git a/disas/libvixl/vixl/globals.h b/disas/libvixl/vixl/globals.h
> index 7099aa599fb..3a71942f1e5 100644
> --- a/disas/libvixl/vixl/globals.h
> +++ b/disas/libvixl/vixl/globals.h
> @@ -40,15 +40,17 @@
>  #define __STDC_FORMAT_MACROS
>  #endif
>  
> -#include <stdint.h>
> +extern "C" {
>  #include <inttypes.h>
> -
> -#include <assert.h>
> -#include <stdarg.h>
> -#include <stdio.h>
>  #include <stdint.h>
> -#include <stdlib.h>
> -#include <stddef.h>
> +}
> +
> +#include <cassert>
> +#include <cstdarg>
> +#include <cstddef>
> +#include <cstdio>
> +#include <cstdlib>
> +
>  #include "vixl/platform.h"
>  
>  
> diff --git a/disas/libvixl/vixl/invalset.h b/disas/libvixl/vixl/invalset.h
> index ffdc0237b47..2e0871f8c3f 100644
> --- a/disas/libvixl/vixl/invalset.h
> +++ b/disas/libvixl/vixl/invalset.h
> @@ -27,7 +27,7 @@
>  #ifndef VIXL_INVALSET_H_
>  #define VIXL_INVALSET_H_
>  
> -#include <string.h>
> +#include <cstring>
>  
>  #include <algorithm>
>  #include <vector>
> diff --git a/disas/libvixl/vixl/platform.h b/disas/libvixl/vixl/platform.h
> index ab588f07f54..26a74de81bb 100644
> --- a/disas/libvixl/vixl/platform.h
> +++ b/disas/libvixl/vixl/platform.h
> @@ -28,7 +28,9 @@
>  #define PLATFORM_H
>  
>  // Define platform specific functionalities.
> +extern "C" {
>  #include <signal.h>
> +}
>  
>  namespace vixl {
>  inline void HostBreakpoint() { raise(SIGINT); }
> diff --git a/disas/libvixl/vixl/utils.h b/disas/libvixl/vixl/utils.h
> index 5ab134e240a..ecb0f1014ab 100644
> --- a/disas/libvixl/vixl/utils.h
> +++ b/disas/libvixl/vixl/utils.h
> @@ -27,8 +27,8 @@
>  #ifndef VIXL_UTILS_H
>  #define VIXL_UTILS_H
>  
> -#include <string.h>
>  #include <cmath>
> +#include <cstring>
>  #include "vixl/globals.h"
>  #include "vixl/compiler-intrinsics.h"
>  
> diff --git a/disas/libvixl/vixl/utils.cc b/disas/libvixl/vixl/utils.cc
> index 3b8bd75fba1..69304d266d7 100644
> --- a/disas/libvixl/vixl/utils.cc
> +++ b/disas/libvixl/vixl/utils.cc
> @@ -25,7 +25,7 @@
>  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
>  
>  #include "vixl/utils.h"
> -#include <stdio.h>
> +#include <cstdio>
>  
>  namespace vixl {
>  
>