MDEV-19235 MariaDB Server compiled for 128 Indexes crashes at startupbb-10.4-wlad-MDEV-19235

With MAX_INDEXIES=64(default), key_map=Bitmap<64> is just a wrapper around
ulonglong and thus "trivial" (can be bzero-ed, or memcpy-ed, and stays
valid still)

With MAX_INDEXES=128, key_map = Bitmap<128> is not a "trivial" type
anymore. The implementation uses MY_BITMAP, and MY_BITMAP contains pointers
which make Bitmap invalid, when it is memcpy-ed/bzero-ed.

The problem in 10.4 is that there are many new key_map members, inside TABLE
or KEY, and those are often memcopied and bzeroed

The fix makes Bitmap "trivial", by inlining most of MY_BITMAP functionality.
pointers/heap allocations are not used anymore.

1 files changed, 0 insertions, 11 deletions

diff --git a/mysys/my_bitmap.c b/mysys/my_bitmap.c
index 4db6b8a44f8..24653fd301f 100644
--- a/mysys/my_bitmap.c
+++ b/mysys/my_bitmap.c
@@ -38,17 +38,6 @@
 #include <m_string.h>
 #include <my_bit.h>
 
-
-/* Create a mask of the significant bits for the last byte (1,3,7,..255) */
-
-static inline uchar last_byte_mask(uint bits)
-{
-  /* Get the number of used bits-1 (0..7) in the last byte */
-  unsigned int const used= (bits - 1U) & 7U;
-  /* Return bitmask for the significant bits */
-  return ((2U << used) - 1);
-}
-
 /*
   Create a mask with the upper 'unused' bits set and the lower 'used'
   bits clear. The bits within each byte is stored in big-endian order.