misc: Replace zero-length arrays with flexible array member (automatic)

Description copied from Linux kernel commit from Gustavo A. R. Silva
(see [3]):

--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).

All these instances of code were found with the help of the
following Coccinelle script:

  @@
  identifier s, m, a;
  type t, T;
  @@
   struct s {
      ...
      t m;
  -   T a[0];
  +   T a[];
  };
  @@
  identifier s, m, a;
  type t, T;
  @@
   struct s {
      ...
      t m;
  -   T a[0];
  +   T a[];
   } QEMU_PACKED;

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=76497732932f
[3] https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?id=17642a2fbd2c1

Inspired-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
index 5219dd0..eb6a37b 100644
--- a/hw/acpi/nvdimm.c
+++ b/hw/acpi/nvdimm.c
@@ -485,7 +485,7 @@ struct NvdimmFuncGetLabelDataOut {
     /* the size of buffer filled by QEMU. */
     uint32_t len;
     uint32_t func_ret_status; /* return status code. */
-    uint8_t out_buf[0]; /* the data got via Get Namesapce Label function. */
+    uint8_t out_buf[]; /* the data got via Get Namesapce Label function. */
 } QEMU_PACKED;
 typedef struct NvdimmFuncGetLabelDataOut NvdimmFuncGetLabelDataOut;
 QEMU_BUILD_BUG_ON(sizeof(NvdimmFuncGetLabelDataOut) > NVDIMM_DSM_MEMORY_SIZE);
@@ -493,7 +493,7 @@ QEMU_BUILD_BUG_ON(sizeof(NvdimmFuncGetLabelDataOut) > NVDIMM_DSM_MEMORY_SIZE);
 struct NvdimmFuncSetLabelDataIn {
     uint32_t offset; /* the offset in the namespace label data area. */
     uint32_t length; /* the size of data is to be written via the function. */
-    uint8_t in_buf[0]; /* the data written to label data area. */
+    uint8_t in_buf[]; /* the data written to label data area. */
 } QEMU_PACKED;
 typedef struct NvdimmFuncSetLabelDataIn NvdimmFuncSetLabelDataIn;
 QEMU_BUILD_BUG_ON(sizeof(NvdimmFuncSetLabelDataIn) +
@@ -510,7 +510,7 @@ struct NvdimmFuncReadFITOut {
     /* the size of buffer filled by QEMU. */
     uint32_t len;
     uint32_t func_ret_status; /* return status code. */
-    uint8_t fit[0]; /* the FIT data. */
+    uint8_t fit[]; /* the FIT data. */
 } QEMU_PACKED;
 typedef struct NvdimmFuncReadFITOut NvdimmFuncReadFITOut;
 QEMU_BUILD_BUG_ON(sizeof(NvdimmFuncReadFITOut) > NVDIMM_DSM_MEMORY_SIZE);