[Xen-devel] [PATCH 0/2] misc: Replace zero-length arrays with flexible array member

[Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>]

v2:
- do not modify qed.h (structure with single member)
- based on hw/scsi/spapr_vscsi fix series

This is a tree-wide cleanup inspired by a Linux kernel commit
(from Gustavo A. R. Silva).

--v-- description start --v--

  The current codebase makes use of the zero-length array language
  extension to the C90 standard, but the preferred mechanism to
  declare variable-length types such as these ones is a flexible
  array member [1], introduced in C99:

  struct foo {
      int stuff;
      struct boo array[];
  };

  By making use of the mechanism above, we will get a compiler
  warning in case the flexible array does not occur last in the
  structure, which will help us prevent some kind of undefined
  behavior bugs from being unadvertenly introduced [2] to the
  Linux codebase from now on.

--^-- description end --^--

Do the similar housekeeping in the QEMU codebase (which uses
C99 since commit 7be41675f7cb).

The first patch is done with the help of a coccinelle semantic
patch. However Coccinelle does not recognize:

  struct foo {
      int stuff;
      struct boo array[];
  } QEMU_PACKED;

but does recognize:

  struct QEMU_PACKED foo {
      int stuff;
      struct boo array[];
  };

I'm not sure why, neither it is worth refactoring all QEMU
structures to use the attributes before the structure name,
so I did the 2nd patch manually.

Anyway this is annoying, because many structures are not handled
by coccinelle. Maybe this needs to be reported to upstream
coccinelle?

I used spatch 1.0.8 with:

  -I include --include-headers \
  --macro-file scripts/cocci-macro-file.h \
  --keep-comments --indent 4

Regards,

Phil.

Based-on: <20200304153311.22959-1-philmd@xxxxxxxxxx>
Supersedes: <20200304005105.27454-1-philmd@xxxxxxxxxx>

Philippe Mathieu-Daudé (2):
  misc: Replace zero-length arrays with flexible array member
    (automatic)
  misc: Replace zero-length arrays with flexible array member (manual)

 docs/interop/vhost-user.rst           |  4 ++--
 bsd-user/qemu.h                       |  2 +-
 contrib/libvhost-user/libvhost-user.h |  2 +-
 hw/m68k/bootinfo.h                    |  2 +-
 hw/scsi/srp.h                         |  6 +++---
 hw/xen/xen_pt.h                       |  2 +-
 include/hw/acpi/acpi-defs.h           | 16 ++++++++--------
 include/hw/arm/smmu-common.h          |  2 +-
 include/hw/boards.h                   |  2 +-
 include/hw/i386/intel_iommu.h         |  3 ++-
 include/hw/s390x/event-facility.h     |  2 +-
 include/hw/s390x/sclp.h               |  8 ++++----
 include/hw/virtio/virtio-iommu.h      |  2 +-
 include/sysemu/cryptodev.h            |  2 +-
 include/tcg/tcg.h                     |  2 +-
 pc-bios/s390-ccw/bootmap.h            |  2 +-
 pc-bios/s390-ccw/sclp.h               |  2 +-
 tests/qtest/libqos/ahci.h             |  2 +-
 block/linux-aio.c                     |  2 +-
 block/vmdk.c                          |  2 +-
 hw/acpi/nvdimm.c                      |  6 +++---
 hw/char/sclpconsole-lm.c              |  2 +-
 hw/char/sclpconsole.c                 |  2 +-
 hw/dma/soc_dma.c                      |  2 +-
 hw/i386/x86.c                         |  2 +-
 hw/misc/omap_l4.c                     |  2 +-
 hw/nvram/eeprom93xx.c                 |  2 +-
 hw/rdma/vmw/pvrdma_qp_ops.c           |  4 ++--
 hw/s390x/virtio-ccw.c                 |  2 +-
 hw/usb/dev-network.c                  |  2 +-
 hw/usb/dev-smartcard-reader.c         |  4 ++--
 hw/virtio/virtio.c                    |  4 ++--
 net/queue.c                           |  2 +-
 target/s390x/ioinst.c                 |  2 +-
 34 files changed, 53 insertions(+), 52 deletions(-)

-- 
2.21.1


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