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| author | Florian Weimer <fweimer@redhat.com> | 2015-05-18 13:58:54 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2015-05-22 11:40:04 +0200 |
| commit | e69dcccbcb53b2c0f3fbe3f6c3e04aadae7e9265 (patch) | |
| tree | 9f68baa8c17a343946e69357767909297843c5c1 /libio/libioP.h | |
| parent | 9124ccf76abc5a2ffe4603e6424b1dc2b5a5db44 (diff) | |
| download | glibc-e69dcccbcb53b2c0f3fbe3f6c3e04aadae7e9265.tar glibc-e69dcccbcb53b2c0f3fbe3f6c3e04aadae7e9265.tar.gz glibc-e69dcccbcb53b2c0f3fbe3f6c3e04aadae7e9265.tar.bz2 glibc-e69dcccbcb53b2c0f3fbe3f6c3e04aadae7e9265.zip | |
Avoid some aliasing violations in libio
Diffstat (limited to 'libio/libioP.h')
| -rw-r--r-- | libio/libioP.h | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/libio/libioP.h b/libio/libioP.h index d8604ca21d..784a47b743 100644 --- a/libio/libioP.h +++ b/libio/libioP.h @@ -32,6 +32,8 @@ FIXME: All of the C++ cruft eventually needs to go away. */ +#include <stddef.h> + #include <errno.h> #ifndef __set_errno # define __set_errno(Val) errno = (Val) @@ -104,17 +106,30 @@ extern "C" { # define _IO_JUMPS_OFFSET 0 #endif +/* Type of MEMBER in struct type TYPE. */ +#define _IO_MEMBER_TYPE(TYPE, MEMBER) __typeof__ (((TYPE){}).MEMBER) + +/* Essentially ((TYPE *) THIS)->MEMBER, but avoiding the aliasing + violation in case THIS has a different pointer type. */ +#define _IO_CAST_FIELD_ACCESS(THIS, TYPE, MEMBER) \ + (*(_IO_MEMBER_TYPE (TYPE, MEMBER) *)(((char *) (THIS)) \ + + offsetof(TYPE, MEMBER))) + #define _IO_JUMPS(THIS) (THIS)->vtable -#define _IO_WIDE_JUMPS(THIS) ((struct _IO_FILE *) (THIS))->_wide_data->_wide_vtable -#define _IO_CHECK_WIDE(THIS) (((struct _IO_FILE *) (THIS))->_wide_data != NULL) +#define _IO_JUMPS_FILE_plus(THIS) \ + _IO_CAST_FIELD_ACCESS ((THIS), struct _IO_FILE_plus, vtable) +#define _IO_WIDE_JUMPS(THIS) \ + _IO_CAST_FIELD_ACCESS ((THIS), struct _IO_FILE, _wide_data)->_wide_vtable +#define _IO_CHECK_WIDE(THIS) \ + (_IO_CAST_FIELD_ACCESS ((THIS), struct _IO_FILE, _wide_data) != NULL) #if _IO_JUMPS_OFFSET # define _IO_JUMPS_FUNC(THIS) \ - (*(struct _IO_jump_t **) ((void *) &_IO_JUMPS ((struct _IO_FILE_plus *) (THIS)) \ + (*(struct _IO_jump_t **) ((void *) &_IO_JUMPS_FILE_plus (THIS) \ + (THIS)->_vtable_offset)) # define _IO_vtable_offset(THIS) (THIS)->_vtable_offset #else -# define _IO_JUMPS_FUNC(THIS) _IO_JUMPS ((struct _IO_FILE_plus *) (THIS)) +# define _IO_JUMPS_FUNC(THIS) _IO_JUMPS_FILE_plus (THIS) # define _IO_vtable_offset(THIS) 0 #endif #define _IO_WIDE_JUMPS_FUNC(THIS) _IO_WIDE_JUMPS(THIS) |