RFR: 8347649: Build fails by clang17 after JDK-8313396

[David Holmes]

On Tue, 14 Jan 2025 12:51:56 GMT, SendaoYan <syan at openjdk.org> wrote:

> Hi all,
> This PR fix build failure by clang17 after JDK-8313396. Before this PR file src/hotspot/share/utilities/forbiddenFunctions.hpp `#include <stdlib.h>` and then  `#include "forbiddenFunctions_posix.hpp"`. System header file <stdlib.h> define `realpath` function, and file forbiddenFunctions_posix.hpp add attribute declaration for `realpath` function, so clang17 report compile warning "attribute declaration must precede definition". This PR switch the sequence of `#include <stdlib.h>` and `#include "forbiddenFunctions_posix.hpp"` in file src/hotspot/share/utilities/forbiddenFunctions.hpp to fix this compile warning issue.
> 
> Below code snippet shows the clang17 compile waning:
> 
> void a(const char *, char *){};
> [[deprecated]] void a(const char *, char *);
> 
> 
> clang -Wall -c ~/compiler-test/zzkk/attribute.cpp
> /home/yansendao/compiler-test/zzkk/attribute.cpp:5:3: warning: attribute declaration must precede definition [-Wignored-attributes]
>     5 | [[deprecated]] void a(const char *, char *);
>       |   ^
> /home/yansendao/compiler-test/zzkk/attribute.cpp:4:6: note: previous definition is here
>     4 | void a(const char *, char *){};
>       |      ^
> 1 warning generated.
> 
> 
> Additional testing:
> 
> - [ ] configure and make with gcc10 with release/fastdebug debug level
> - [ ] configure and make with gcc14 with release/fastdebug debug level

The backout was done, so this PR and issue can be closed. Thanks

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PR Comment: https://git.openjdk.org/jdk/pull/23102#issuecomment-2591377025