When building gcc 16 for 32-bit Windows, I noticed this warning:
gcc/libgfortran/caf/shmem/shared_memory.c: In function 'shared_memory_init':
gcc/libgfortran/caf/shmem/shared_memory.c:173:35: warning: right shift count >=
width of type [-Wshift-count-overflow]
173 | size >> (sizeof (DWORD) * 8),
| ^~
CreateFileMapping takes the maximum mapping size split into high and low
DWORDs. Cast size through uint64_t before computing the high DWORD so 32-bit
Windows targets do not shift a 32-bit size_t by 32 bits.
libgfortran/ChangeLog:
* caf/shmem/shared_memory.c: Include stdint.h.
(shared_memory_init): Cast size through uint64_t before computing the
high-order CreateFileMapping size DWORD.
Signed-off-by: Peter Damianov <[email protected]>
---
libgfortran/caf/shmem/shared_memory.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/libgfortran/caf/shmem/shared_memory.c
b/libgfortran/caf/shmem/shared_memory.c
index a2520a89cc7..168906b0dc0 100644
--- a/libgfortran/caf/shmem/shared_memory.c
+++ b/libgfortran/caf/shmem/shared_memory.c
@@ -35,6 +35,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If
not, see
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
+#include <stdint.h>
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#elif defined(WIN32)
@@ -170,8 +171,8 @@ shared_memory_init (shared_memory_act *mem, size_t size)
#elif defined(WIN32)
mem->shm_fd
= CreateFileMapping (INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE,
- size >> (sizeof (DWORD) * 8),
- (DWORD) (size & ~((DWORD) 0)), shm_name);
+ (DWORD) ((uint64_t) size >> 32),
+ (DWORD) size, shm_name);
if (mem->shm_fd == NULL)
{
LPVOID lpMsgBuf;
--
2.54.0
