Re: [Qemu-devel] Hacks for building on gcc 7 / Fedora 26

[Philippe Mathieu-Daudé]

On 04/07/2017 04:21 PM, Philippe Mathieu-Daudé wrote:
> Hi Dave,
>
> On 04/07/2017 11:38 AM, Dr. David Alan Gilbert wrote:
> > Hi,
> >    Fedora 26 has gcc 7.0.1 which has the normal compliment
> > of new fussy warnings; so far I've posted :
> >
> > tests/check-qdict: Fix missing brackets
> > slirp/smb: Replace constant strings by glib string
> >
> > that fix one actual mistake and work around something it's being
> > fussy over.
> >
> > But I've also got a pile of hacks, attached below that I'm
> > not too sure what I'll do with them yet, but they're attached

ping ... What do we do with them?

> > for anyone else trying to build.  Note they're smoke-only-tested.
> >
> > I also have gcc bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80346
> > filed for what I reckon is a couple of overly pessimistic warnings.
> >
> > Enjoy,
> >
> > Dave
> >
> > From 15353ce59e35e1d85927138982241491ea65cee2 Mon Sep 17 00:00:00 2001
> > From: "Dr. David Alan Gilbert" <address@hidden>
> > Date: Thu, 6 Apr 2017 15:44:50 +0100
> > Subject: [HACK!] Hacks for f26 build
> >
> > ---
> >  block/blkdebug.c         | 4 ++--
> >  block/blkverify.c        | 4 ++--
> >  hw/usb/bus.c             | 5 +++--
> >  include/qemu/iov.h       | 4 ++--
> >  tests/bios-tables-test.c | 2 +-
> >  5 files changed, 10 insertions(+), 9 deletions(-)
> >
> > diff --git a/block/blkdebug.c b/block/blkdebug.c
> > index 67e8024e36..34c645d095 100644
> > --- a/block/blkdebug.c
> > +++ b/block/blkdebug.c
> > @@ -689,9 +689,9 @@ static void 
> > blkdebug_refresh_filename(BlockDriverState *bs, QDict *options)
> >      }
> >
> >      if (!force_json && bs->file->bs->exact_filename[0]) {
> > -        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
> > +        g_assert_cmpint(snprintf(bs->exact_filename, 
> > sizeof(bs->exact_filename),
> >                   "blkdebug:%s:%s", s->config_file ?: "",
> > -                 bs->file->bs->exact_filename);
> > +                 bs->file->bs->exact_filename), <, 
> > sizeof(bs->exact_filename));
>
> I'm not sure this works as expected if you compile with CPPFLAGS 
> +=-DG_DISABLE_ASSERT.
>
> I added in me docker TODO "also build with -DG_DISABLE_ASSERT".
>
> >      }
> >
> >      opts = qdict_new();
> > diff --git a/block/blkverify.c b/block/blkverify.c
> > index 9a1e21c6ad..d038947a5a 100644
> > --- a/block/blkverify.c
> > +++ b/block/blkverify.c
> > @@ -305,10 +305,10 @@ static void 
> > blkverify_refresh_filename(BlockDriverState *bs, QDict *options)
> >      if (bs->file->bs->exact_filename[0]
> >          && s->test_file->bs->exact_filename[0])
> >      {
> > -        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
> > +        g_assert_cmpint(snprintf(bs->exact_filename, 
> > sizeof(bs->exact_filename),
> >                   "blkverify:%s:%s",
> >                   bs->file->bs->exact_filename,
> > -                 s->test_file->bs->exact_filename);
> > +                 s->test_file->bs->exact_filename), <, 
> > sizeof(bs->exact_filename));
> >      }
> >  }
> >
> > diff --git a/hw/usb/bus.c b/hw/usb/bus.c
> > index 24f1608b4b..6023f3b419 100644
> > --- a/hw/usb/bus.c
> > +++ b/hw/usb/bus.c
> > @@ -8,6 +8,7 @@
> >  #include "monitor/monitor.h"
> >  #include "trace.h"
> >  #include "qemu/cutils.h"
> > +#include <glib.h>
> >
> >  static void usb_bus_dev_print(Monitor *mon, DeviceState *qdev, int 
> > indent);
> >
> > @@ -407,8 +408,8 @@ void usb_register_companion(const char *masterbus, 
> > USBPort *ports[],
> >  void usb_port_location(USBPort *downstream, USBPort *upstream, int 
> > portnr)
> >  {
> >      if (upstream) {
> > -        snprintf(downstream->path, sizeof(downstream->path), "%s.%d",
> > -                 upstream->path, portnr);
> > +        g_assert_cmpint(snprintf(downstream->path, 
> > sizeof(downstream->path), "%s.%d",
> > +                 upstream->path, portnr), <, sizeof(downstream->path));
> >          downstream->hubcount = upstream->hubcount + 1;
> >      } else {
> >          snprintf(downstream->path, sizeof(downstream->path), "%d", 
> > portnr);
> > diff --git a/include/qemu/iov.h b/include/qemu/iov.h
> > index bd9fd55b0a..ebb0221140 100644
> > --- a/include/qemu/iov.h
> > +++ b/include/qemu/iov.h
> > @@ -46,7 +46,7 @@ static inline size_t
> >  iov_from_buf(const struct iovec *iov, unsigned int iov_cnt,
> >               size_t offset, const void *buf, size_t bytes)
> >  {
> > -    if (__builtin_constant_p(bytes) && iov_cnt &&
> > +    if (__builtin_constant_p(bytes) && iov_cnt && bytes <= INT_MAX &&
> >          offset <= iov[0].iov_len && bytes <= iov[0].iov_len - offset) {
> >          memcpy(iov[0].iov_base + offset, buf, bytes);
> >          return bytes;
> > @@ -59,7 +59,7 @@ static inline size_t
> >  iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt,
> >             size_t offset, void *buf, size_t bytes)
> >  {
> > -    if (__builtin_constant_p(bytes) && iov_cnt &&
> > +    if (__builtin_constant_p(bytes) && iov_cnt && bytes <= INT_MAX &&
> >          offset <= iov[0].iov_len && bytes <= iov[0].iov_len - offset) {
> >          memcpy(buf, iov[0].iov_base + offset, bytes);
> >          return bytes;
> > diff --git a/tests/bios-tables-test.c b/tests/bios-tables-test.c
> > index 88dbf97853..c55de4f65b 100644
> > --- a/tests/bios-tables-test.c
> > +++ b/tests/bios-tables-test.c
> > @@ -98,7 +98,7 @@ static void test_acpi_rsdt_table(test_data *data)
> >      AcpiRsdtDescriptorRev1 *rsdt_table = &data->rsdt_table;
> >      uint32_t addr = data->rsdp_table.rsdt_physical_address;
> >      uint32_t *tables;
> > -    int tables_nr;
> > +    unsigned int tables_nr;
>
> Personally I prefer size_t here.
>
> >      uint8_t checksum;
> >
> >      /* read the header */
>
> regards,
> Phil.