Snap for 5434517 from 10b0fd4a65a5cb1688336e6d988d20229102c88f to qt-releaseandroid-vts-10.0_r5android-vts-10.0_r4android-vts-10.0_r3android-vts-10.0_r2android-vts-10.0_r1android-mainline-10.0.0_r3android-mainline-10.0.0_r2android-mainline-10.0.0_r1android-cts-10.0_r5android-cts-10.0_r4android-cts-10.0_r3android-cts-10.0_r2android-cts-10.0_r1android-10.0.0_r6android-10.0.0_r5android-10.0.0_r46android-10.0.0_r4android-10.0.0_r3android-10.0.0_r2android-10.0.0_r17android-10.0.0_r11android-10.0.0_r10android-10.0.0_r1android10-tests-releaseandroid10-security-releaseandroid10-s3-releaseandroid10-s2-releaseandroid10-s1-releaseandroid10-releaseandroid10-mainline-releaseandroid10-mainline-a-releaseandroid10-gsi

Change-Id: Icf7f1a3252c55f02d3e313ee704773f1def1257a

1 files changed, 5 insertions, 1 deletions

diff --git a/src/google/protobuf/io/coded_stream.h b/src/google/protobuf/io/coded_stream.h
index c81a33ac6..7b742a18e 100644
--- a/src/google/protobuf/io/coded_stream.h
+++ b/src/google/protobuf/io/coded_stream.h
@@ -985,7 +985,11 @@ inline std::pair<uint32, bool> CodedInputStream::ReadTagWithCutoff(
   }
   // Slow path
   last_tag_ = ReadTagFallback(first_byte_or_zero);
-  return std::make_pair(last_tag_, static_cast<uint32>(last_tag_ - 1) < cutoff);
+  // If last_tag_ == 0 we want to return { 0, false } so the following overflow is intended.
+  // We use __builtin_add_overflow to appease the sub-overflow UB sanitizer.
+  uint32_t last_tag_minus_one;
+  __builtin_add_overflow(last_tag_, -1, &last_tag_minus_one);
+  return std::make_pair(last_tag_, last_tag_minus_one < cutoff);
 }
 
 inline bool CodedInputStream::LastTagWas(uint32 expected) {