Skip to contentSkip to conversation

scripts/dtc: Replace zero-length array with DECLARE_FLEX_ARRAY() helper

PATCH In review [email protected] 3 participants 3 messages Nov 15, 2022 Device tree

lore
Share & tools
lore

[email protected]

author
#0 lore raw

PATCH 1/1 scripts/dtc: Replace zero-length array with DECLARE_FLEX_ARRAY() helper

From: guo ziliang <[email protected]>

Zero-length arrays are deprecated and we are moving towards adopting C99 flexible-array members, instead. So, replace zero-length arrays declarations in anonymous union with the new DECLARE_FLEX_ARRAY() helper macro.

Signed-off-by guo ziliang <[email protected]>
---
 scripts/dtc/libfdt/fdt.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
scripts/dtc/libfdt/fdt.h +2 -2
index f2e6880..f66fff1 100644
@@ -35,14 +35,14 @@ struct fdt_reserve_entry {
 
 struct fdt_node_header {
        fdt32_t tag;
-       char name[0];
+       DECLARE_FLEX_ARRAY(char, name);
 };
 
 struct fdt_property {
        fdt32_t tag;
        fdt32_t len;
        fdt32_t nameoff;
-       char data[0];
+       DECLARE_FLEX_ARRAY(char, data);
 };
 
 #endif /* !__ASSEMBLY */

--
1.8.3.1

#1 lore raw
Quoted 21 lines · On Tue, Nov 15, 2022 at 09:03:27AM +0800, [email protected] wrote:

From: guo ziliang <[email protected]>

Zero-length arrays are deprecated and we are moving towards adopting C99 flexible-array members, instead. So, replace zero-length arrays declarations in anonymous union with the new DECLARE_FLEX_ARRAY() helper macro.

Signed-off-by guo ziliang <[email protected]>
---
 scripts/dtc/libfdt/fdt.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
scripts/dtc/libfdt/fdt.h +0 -1
index f2e6880..f66fff1 100644
@@ -35,14 +35,14 @@ struct fdt_reserve_entry {
 
 struct fdt_node_header {
        fdt32_t tag;
-       char name[0];

scripts/dtc/libfdt/fdt.h struct fdt_reserve_entry { · line 46

Quoted 10 lines
scripts/dtc/libfdt/fdt.h +2 -1
+       DECLARE_FLEX_ARRAY(char, name);
 };
 
 struct fdt_property {
        fdt32_t tag;
        fdt32_t len;
        fdt32_t nameoff;
-       char data[0];
+       DECLARE_FLEX_ARRAY(char, data);
 };

This was addressed in commit:

5224f7909617 ("treewide: Replace zero-length arrays with flexible-array members")

My question here is why these changes were reverted by commit:

        ea3723a541c1 ("scripts/dtc: Update to upstream version v1.6.1-63-g55778a03df61")

?? :O

Thanks
--
Gustavo

#2 lore raw
In reply to [email protected]
Quoted 8 lines · On Mon, Nov 14, 2022 at 7:03 PM <[email protected]> wrote:

From: guo ziliang <[email protected]>

Zero-length arrays are deprecated and we are moving towards adopting C99 flexible-array members, instead. So, replace zero-length arrays declarations in anonymous union with the new DECLARE_FLEX_ARRAY() helper macro.

Quoted 4 lines
Signed-off-by guo ziliang <[email protected]>
---
 scripts/dtc/libfdt/fdt.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Changes to dtc/libfdt must go upstream first and then we sync upstream back to the kernel.