Merge "configure: add --enable-coefficient-range-checking"

configure

@@ -46,6 +46,9 @@ Advanced options:
   ${toggle_realtime_only}         enable this option while building for real-time encoding
   ${toggle_onthefly_bitpacking}   enable on-the-fly bitpacking in real-time encoding
   ${toggle_error_concealment}     enable this option to get a decoder which is able to conceal losses
+  ${toggle_coefficient_range_checking}
+                                  enable decoder to check if intermediate
+                                  transform coefficients are in valid range
   ${toggle_runtime_cpu_detect}    runtime cpu detection
   ${toggle_shared}                shared library support
   ${toggle_static}                static library support
@@ -327,6 +330,7 @@ CONFIG_LIST="
     encode_perf_tests
     multi_res_encoding
     temporal_denoising
+    coefficient_range_checking
     experimental
     size_limit
     ${EXPERIMENT_LIST}
@@ -384,6 +388,7 @@ CMDLINE_SELECT="
     encode_perf_tests
     multi_res_encoding
     temporal_denoising
+    coefficient_range_checking
     experimental
 "
 

vp9/common/vp9_idct.h

@@ -81,6 +81,16 @@ static const int sinpi_4_9 = 15212;
 
 static INLINE int dct_const_round_shift(int input) {
   int rv = ROUND_POWER_OF_TWO(input, DCT_CONST_BITS);
+#if CONFIG_COEFFICIENT_RANGE_CHECKING
+  // For valid VP9 input streams, intermediate stage coefficients should always
+  // stay within the range of a signed 16 bit integer. Coefficients can go out
+  // of this range for invalid/corrupt VP9 streams. However, strictly checking
+  // this range for every intermediate coefficient can burdensome for a decoder,
+  // therefore the following assertion is only enabled when configured with
+  // --enable-coefficient-range-checking.
+  assert(INT16_MIN <= rv);
+  assert(rv <= INT16_MAX);
+#endif
   return (int16_t)rv;
 }