src/pcre2_intmodedep.h: fix alignment of fields in struct heapframe pcre2_intmodedep.h has a check to verify that the size of the struct heapframe is a multiple of 4 bytes. On most architectures this works fine, but not on m68k. Indeed, when building the 16-bit variant of pcre2, the heapframe structure contains: PCRE2_UCHAR occu[2]; PCRE2_SPTR eptr; Where PCRE2_UCHAR is a 16-bit data type, and PCRE2_SPTR is a pointer. The occu[] array starts at byte 0x32, so not aligned on a 32-bit boundary. With 2 x 16-bit, the occur[] array ends at byte 0x36. Now, on most architectures, the alignment required for a pointer will make the eptr field start at 0x38 (on 32 bit architectures). However, on m68k, it is fine to have a pointer aligned only on a 16-bit boundary, and the eptr pointer will be at offset 0x36. This doesn't cause a problem per-se, but breaks the check that heapframe should be a multiple of 4 bytes. To fix this, we make sure eptr is aligned by introducing an unused field of 16 bits after the occu[] array (in the 16-bit variant) or after the occu[] array (in the 32-bit variant). These choices have been made to keep the structure layout unchanged. Fixes the following build failure on m68k: src/pcre2_intmodedep.h:818:14: error: size of array 'check_heapframe_size' is negative typedef char check_heapframe_size[ ^~~~~~~~~~~~~~~~~~~~ Signed-off-by: Thomas Petazzoni Upstream: https://bugs.exim.org/show_bug.cgi?id=2247 Index: src/pcre2_intmodedep.h =================================================================== --- a/src/pcre2_intmodedep.h (revision 923) +++ b/src/pcre2_intmodedep.h (working copy) @@ -797,7 +797,9 @@ PCRE2_UCHAR occu[6]; /* Used for other case code units */ #elif PCRE2_CODE_UNIT_WIDTH == 16 PCRE2_UCHAR occu[2]; /* Used for other case code units */ + uint8_t unused[2]; /* Ensure 32 bit alignment */ #else + uint8_t unused[2]; /* Ensure 32 bit alignment */ PCRE2_UCHAR occu[1]; /* Used for other case code units */ #endif