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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 2/2] misc: Replace zero-length arrays with flexible array member (manual)
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 command (then manual analysis):
git grep -F '[0];'
[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@xxxxxxxxxxxxxx>
Signed-off-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
---
docs/interop/vhost-user.rst | 4 ++--
block/qed.h | 2 +-
include/hw/acpi/acpi-defs.h | 4 ++--
include/hw/boards.h | 2 +-
include/hw/s390x/event-facility.h | 2 +-
include/hw/s390x/sclp.h | 8 ++++----
block/vmdk.c | 2 +-
hw/char/sclpconsole-lm.c | 2 +-
hw/char/sclpconsole.c | 2 +-
hw/s390x/virtio-ccw.c | 2 +-
target/s390x/ioinst.c | 2 +-
11 files changed, 16 insertions(+), 16 deletions(-)
diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
index 401652397c..3b1b6602c7 100644
--- a/docs/interop/vhost-user.rst
+++ b/docs/interop/vhost-user.rst
@@ -568,7 +568,7 @@ For split virtqueue, queue region can be implemented as:
uint16_t used_idx;
/* Used to track the state of each descriptor in descriptor table */
- DescStateSplit desc[0];
+ DescStateSplit desc[];
} QueueRegionSplit;
To track inflight I/O, the queue region should be processed as follows:
@@ -690,7 +690,7 @@ For packed virtqueue, queue region can be implemented as:
uint8_t padding[7];
/* Used to track the state of each descriptor fetched from descriptor
ring */
- DescStatePacked desc[0];
+ DescStatePacked desc[];
} QueueRegionPacked;
To track inflight I/O, the queue region should be processed as follows:
diff --git a/block/qed.h b/block/qed.h
index 42c115d822..87428ba00e 100644
--- a/block/qed.h
+++ b/block/qed.h
@@ -103,7 +103,7 @@ typedef struct {
} QEMU_PACKED QEDHeader;
typedef struct {
- uint64_t offsets[0]; /* in bytes */
+ uint64_t offsets[]; /* in bytes */
} QEDTable;
/* The L2 cache is a simple write-through cache for L2 structures */
diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
index 19f7ba7b70..c13327fa78 100644
--- a/include/hw/acpi/acpi-defs.h
+++ b/include/hw/acpi/acpi-defs.h
@@ -152,7 +152,7 @@ typedef struct AcpiSerialPortConsoleRedirection
*/
struct AcpiRsdtDescriptorRev1 {
ACPI_TABLE_HEADER_DEF /* ACPI common table header */
- uint32_t table_offset_entry[0]; /* Array of pointers to other */
+ uint32_t table_offset_entry[]; /* Array of pointers to other */
/* ACPI tables */
} QEMU_PACKED;
typedef struct AcpiRsdtDescriptorRev1 AcpiRsdtDescriptorRev1;
@@ -162,7 +162,7 @@ typedef struct AcpiRsdtDescriptorRev1
AcpiRsdtDescriptorRev1;
*/
struct AcpiXsdtDescriptorRev2 {
ACPI_TABLE_HEADER_DEF /* ACPI common table header */
- uint64_t table_offset_entry[0]; /* Array of pointers to other */
+ uint64_t table_offset_entry[]; /* Array of pointers to other */
/* ACPI tables */
} QEMU_PACKED;
typedef struct AcpiXsdtDescriptorRev2 AcpiXsdtDescriptorRev2;
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 9bc42dfb22..c96120d15f 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -71,7 +71,7 @@ typedef struct CPUArchId {
*/
typedef struct {
int len;
- CPUArchId cpus[0];
+ CPUArchId cpus[];
} CPUArchIdList;
/**
diff --git a/include/hw/s390x/event-facility.h
b/include/hw/s390x/event-facility.h
index bdc32a3c09..700a610f33 100644
--- a/include/hw/s390x/event-facility.h
+++ b/include/hw/s390x/event-facility.h
@@ -122,7 +122,7 @@ typedef struct MDBO {
typedef struct MDB {
MdbHeader header;
- MDBO mdbo[0];
+ MDBO mdbo[];
} QEMU_PACKED MDB;
typedef struct SclpMsg {
diff --git a/include/hw/s390x/sclp.h b/include/hw/s390x/sclp.h
index c54413b78c..cd7b24359f 100644
--- a/include/hw/s390x/sclp.h
+++ b/include/hw/s390x/sclp.h
@@ -132,7 +132,7 @@ typedef struct ReadInfo {
uint16_t highest_cpu;
uint8_t _reserved5[124 - 122]; /* 122-123 */
uint32_t hmfai;
- struct CPUEntry entries[0];
+ struct CPUEntry entries[];
} QEMU_PACKED ReadInfo;
typedef struct ReadCpuInfo {
@@ -142,7 +142,7 @@ typedef struct ReadCpuInfo {
uint16_t nr_standby; /* 12-13 */
uint16_t offset_standby; /* 14-15 */
uint8_t reserved0[24-16]; /* 16-23 */
- struct CPUEntry entries[0];
+ struct CPUEntry entries[];
} QEMU_PACKED ReadCpuInfo;
typedef struct ReadStorageElementInfo {
@@ -151,7 +151,7 @@ typedef struct ReadStorageElementInfo {
uint16_t assigned;
uint16_t standby;
uint8_t _reserved0[16 - 14]; /* 14-15 */
- uint32_t entries[0];
+ uint32_t entries[];
} QEMU_PACKED ReadStorageElementInfo;
typedef struct AttachStorageElement {
@@ -159,7 +159,7 @@ typedef struct AttachStorageElement {
uint8_t _reserved0[10 - 8]; /* 8-9 */
uint16_t assigned;
uint8_t _reserved1[16 - 12]; /* 12-15 */
- uint32_t entries[0];
+ uint32_t entries[];
} QEMU_PACKED AttachStorageElement;
typedef struct AssignStorage {
diff --git a/block/vmdk.c b/block/vmdk.c
index 20e909d997..8466051bc9 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -187,7 +187,7 @@ typedef struct VmdkMetaData {
typedef struct VmdkGrainMarker {
uint64_t lba;
uint32_t size;
- uint8_t data[0];
+ uint8_t data[];
} QEMU_PACKED VmdkGrainMarker;
enum {
diff --git a/hw/char/sclpconsole-lm.c b/hw/char/sclpconsole-lm.c
index c420dc066e..2b5f37b6a2 100644
--- a/hw/char/sclpconsole-lm.c
+++ b/hw/char/sclpconsole-lm.c
@@ -31,7 +31,7 @@
typedef struct OprtnsCommand {
EventBufferHeader header;
MDMSU message_unit;
- char data[0];
+ char data[];
} QEMU_PACKED OprtnsCommand;
/* max size for line-mode data in 4K SCCB page */
diff --git a/hw/char/sclpconsole.c b/hw/char/sclpconsole.c
index 1fa124dab9..5c7664905e 100644
--- a/hw/char/sclpconsole.c
+++ b/hw/char/sclpconsole.c
@@ -25,7 +25,7 @@
typedef struct ASCIIConsoleData {
EventBufferHeader ebh;
- char data[0];
+ char data[];
} QEMU_PACKED ASCIIConsoleData;
/* max size for ASCII data in 4K SCCB page */
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 50cf95b781..64f928fc7d 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -193,7 +193,7 @@ typedef struct VirtioThinintInfo {
typedef struct VirtioRevInfo {
uint16_t revision;
uint16_t length;
- uint8_t data[0];
+ uint8_t data[];
} QEMU_PACKED VirtioRevInfo;
/* Specify where the virtqueues for the subchannel are in guest memory. */
diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
index c437a1d8c6..0e840cc579 100644
--- a/target/s390x/ioinst.c
+++ b/target/s390x/ioinst.c
@@ -347,7 +347,7 @@ typedef struct ChscResp {
uint16_t len;
uint16_t code;
uint32_t param;
- char data[0];
+ char data[];
} QEMU_PACKED ChscResp;
#define CHSC_MIN_RESP_LEN 0x0008
--
2.21.1
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