Commit d2236198 authored by David Sterba's avatar David Sterba Committed by Herbert Xu
Browse files

lib/lzo: add unlikely hints to overrun checks 



The NEED_* macros do an implicit goto in case the safety bounds checks
fail. Add the unlikely hints as this is the error case and not a hot
path. The final assembly is slightly shorter and some jumps got
reordered according to the hints.

   text    data     bss     dec     hex filename
   2294      16       0    2310     906 pre/lzo1x_decompress_safe.o
   2277      16       0    2293     8f5 post/lzo1x_decompress_safe.o

   text    data     bss     dec     hex filename
   3444      48       0    3492     da4 pre/lzo1x_compress_safe.o
   3372      48       0    3420     d5c post/lzo1x_compress_safe.o

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 817fcdbd

lib/lzo/lzo1x_compress.c

+1 −1
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ 
#define HAVE_OP(x) 1

#endif



#define NEED_OP(x) if (!HAVE_OP(x)) goto output_overrun

#define NEED_OP(x) if (unlikely(!HAVE_OP(x))) goto output_overrun



static noinline int

LZO_SAFE(lzo1x_1_do_compress)(const unsigned char *in, size_t in_len,

lib/lzo/lzo1x_decompress_safe.c

+3 −3
Original line number Diff line number Diff line
@@ -22,9 +22,9 @@ 


#define HAVE_IP(x)      ((size_t)(ip_end - ip) >= (size_t)(x))

#define HAVE_OP(x)      ((size_t)(op_end - op) >= (size_t)(x))

#define NEED_IP(x)      if (!HAVE_IP(x)) goto input_overrun

#define NEED_OP(x)      if (!HAVE_OP(x)) goto output_overrun

#define TEST_LB(m_pos)  if ((m_pos) < out) goto lookbehind_overrun

#define NEED_IP(x)      if (unlikely(!HAVE_IP(x))) goto input_overrun

#define NEED_OP(x)      if (unlikely(!HAVE_OP(x))) goto output_overrun

#define TEST_LB(m_pos)  if (unlikely((m_pos) < out)) goto lookbehind_overrun



/* This MAX_255_COUNT is the maximum number of times we can add 255 to a base

 * count without overflowing an integer. The multiply will overflow when