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Pad 'Left' when building under ASan

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The neon intrinsics are not able to load just the 4 values that are
used. In vpx_dsp/arm/intrapred_neon.c:dc_4x4 it loads 8 values for both
the 'above' and 'left' computations, but only uses the sum of the first
4 values.

BUG=webm:1268

Change-Id: I937113d7e3a21e25bebde3593de0446bf6b0115a
This commit is contained in:
Johann 2016-07-27 14:19:20 -07:00
parent 85e111b3ba
commit a7a8e07a44
2 changed files with 24 additions and 1 deletions
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15
vp8/common/reconintra4x4.c
View File

@ -15,6 +15,8 @@
#include "vp8_rtcd.h"
#include "blockd.h"
#include "reconintra4x4.h"
#include "vp8/common/common.h"
#include "vpx_ports/mem.h"
typedef void (*intra_pred_fn)(uint8_t *dst, ptrdiff_t stride,
const uint8_t *above, const uint8_t *left);
@ -38,8 +40,19 @@ void vp8_intra4x4_predict(unsigned char *above, unsigned char *yleft,
int left_stride, B_PREDICTION_MODE b_mode,
unsigned char *dst, int dst_stride,
unsigned char top_left) {
unsigned char Left[4];
unsigned char Aboveb[12], *Above = Aboveb + 4;
#if HAVE_NEON
// Neon intrinsics are unable to load 32 bits, or 4 8 bit values. Instead, it
// over reads but does not use the extra 4 values.
unsigned char Left[8];
#if VPX_WITH_ASAN
// Silence an 'uninitialized read' warning. Although uninitialized values are
// indeed read, they are not used.
vp8_zero_array(Left, 8);
#endif // VPX_WITH_ASAN
#else
unsigned char Left[4];
#endif // HAVE_NEON
Left[0] = yleft[0];
Left[1] = yleft[left_stride];

10
vpx_ports/mem.h
View File

@ -48,4 +48,14 @@
#define CONVERT_TO_BYTEPTR(x) ((uint8_t *)(((uintptr_t)(x)) >> 1))
#endif // CONFIG_VP9_HIGHBITDEPTH
#if !defined(__has_feature)
#define __has_feature(x) 0
#endif // !defined(__has_feature)
#if __has_feature(address_sanitizer) || __SANITIZE_ADDRESS__
#define VPX_WITH_ASAN 1
#else
#define VPX_WITH_ASAN 0
#endif // __has_feature(address_sanitizer) || __SANITIZE_ADDRESS
#endif // VPX_PORTS_MEM_H_