Add functions to interact with ASan and MSan, and some sample uses

webrtc/common_audio/signal_processing/filter_ma_fast_q12.c

 /*
  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 
 /*
  * This file contains the function WebRtcSpl_FilterMAFastQ12().
  * The description header can be found in signal_processing_library.h
  *
  */
 
 #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
 
+#include "webrtc/base/sanitizer.h"
+
 void WebRtcSpl_FilterMAFastQ12(const int16_t* in_ptr,
                                int16_t* out_ptr,
                                const int16_t* B,
                                size_t B_length,
                                size_t length)
 {
     size_t i, j;
+
+    rtc_MsanCheckInitialized(B, sizeof(B[0]), B_length);
+    rtc_MsanCheckInitialized(in_ptr - B_length + 1, sizeof(in_ptr[0]),
+                             B_length + length - 1);

[kwiberg-webrtc, 2016/08/30 19:55:28]

This is the sort of rtc_MsanCheckInitialized() call that one doesn't want to
see, since it shows that the code was written by crazy people who were
nevertheless brilliant since they got it to mostly work. However, removing it
would be like shooting the messenger and sweeping the body under the rug.

[hlundin-webrtc, 2016/09/01 13:41:35]

What?! You don't like functions that use memory "to the left" of the data
pointer given?

[kwiberg-webrtc, 2016/09/02 07:30:16]

Well, as long as you don't document what memory range your function accesses I
guess it's OK.

+
     for (i = 0; i < length; i++)
     {
         int32_t o = 0;
 
         for (j = 0; j < B_length; j++)
         {
           o += B[j] * in_ptr[i - j];
         }
 
         // If output is higher than 32768, saturate it. Same with negative side
         // 2^27 = 134217728, which corresponds to 32768 in Q12
 
         // Saturate the output
         o = WEBRTC_SPL_SAT((int32_t)134215679, o, (int32_t)-134217728);
 
         *out_ptr++ = (int16_t)((o + (int32_t)2048) >> 12);
     }
     return;
 }