diff options
Diffstat (limited to 'chromium/third_party/libjpeg_turbo/google.patch')
| -rw-r--r-- | chromium/third_party/libjpeg_turbo/google.patch | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/chromium/third_party/libjpeg_turbo/google.patch b/chromium/third_party/libjpeg_turbo/google.patch index 9fcfe9bad30..8a9179dcc7c 100644 --- a/chromium/third_party/libjpeg_turbo/google.patch +++ b/chromium/third_party/libjpeg_turbo/google.patch @@ -1767,3 +1767,78 @@ Index: jdhuff.c METHODDEF(boolean) decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data) +Index: jchuff.c +=================================================================== +--- jchuff.c (revision 1219) ++++ jchuff.c (revision 1220) +@@ -22,8 +22,36 @@ + #include "jchuff.h" /* Declarations shared with jcphuff.c */ + #include <limits.h> + ++/* ++ * NOTE: If USE_CLZ_INTRINSIC is defined, then clz/bsr instructions will be ++ * used for bit counting rather than the lookup table. This will reduce the ++ * memory footprint by 64k, which is important for some mobile applications ++ * that create many isolated instances of libjpeg-turbo (web browsers, for ++ * instance.) This may improve performance on some mobile platforms as well. ++ * This feature is enabled by default only on ARM processors, because some x86 ++ * chips have a slow implementation of bsr, and the use of clz/bsr cannot be ++ * shown to have a significant performance impact even on the x86 chips that ++ * have a fast implementation of it. When building for ARMv6, you can ++ * explicitly disable the use of clz/bsr by adding -mthumb to the compiler ++ * flags (this defines __thumb__). ++ */ ++ ++/* NOTE: Both GCC and Clang define __GNUC__ */ ++#if defined __GNUC__ && defined __arm__ ++#if !defined __thumb__ || defined __thumb2__ ++#define USE_CLZ_INTRINSIC ++#endif ++#endif ++ ++#ifdef USE_CLZ_INTRINSIC ++#define JPEG_NBITS_NONZERO(x) (32 - __builtin_clz(x)) ++#define JPEG_NBITS(x) (x ? JPEG_NBITS_NONZERO(x) : 0) ++#else + static unsigned char jpeg_nbits_table[65536]; + static int jpeg_nbits_table_init = 0; ++#define JPEG_NBITS(x) (jpeg_nbits_table[x]) ++#define JPEG_NBITS_NONZERO(x) JPEG_NBITS(x) ++#endif + + #ifndef min + #define min(a,b) ((a)<(b)?(a):(b)) +@@ -272,6 +300,7 @@ + dtbl->ehufsi[i] = huffsize[p]; + } + ++#ifndef USE_CLZ_INTRINSIC + if(!jpeg_nbits_table_init) { + for(i = 0; i < 65536; i++) { + int nbits = 0, temp = i; +@@ -280,6 +309,7 @@ + } + jpeg_nbits_table_init = 1; + } ++#endif + } + + +@@ -482,7 +512,7 @@ + temp2 += temp3; + + /* Find the number of bits needed for the magnitude of the coefficient */ +- nbits = jpeg_nbits_table[temp]; ++ nbits = JPEG_NBITS(temp); + + /* Emit the Huffman-coded symbol for the number of bits */ + code = dctbl->ehufco[nbits]; +@@ -516,7 +546,7 @@ + temp ^= temp3; \ + temp -= temp3; \ + temp2 += temp3; \ +- nbits = jpeg_nbits_table[temp]; \ ++ nbits = JPEG_NBITS_NONZERO(temp); \ + /* if run length > 15, must emit special run-length-16 codes (0xF0) */ \ + while (r > 15) { \ + EMIT_BITS(code_0xf0, size_0xf0) \ |