[kudu] branch master updated: [gutil] fix ASAN warning in CountOnes()

[achennaka]

This is an automated email from the ASF dual-hosted git repository.

achennaka pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/kudu.git


The following commit(s) were added to refs/heads/master by this push:
     new 8aab39e8b [gutil] fix ASAN warning in CountOnes()
8aab39e8b is described below

commit 8aab39e8b7601c75b0c516c82f1ea6b85c5cfcd6
Author: Alexey Serbin <ale...@apache.org>
AuthorDate: Tue Oct 10 19:52:00 2023 -0700

    [gutil] fix ASAN warning in CountOnes()
    
    Running various tests on aarch64 (Graviton3) under ASAN produced
    warnings like below:
    
      src/kudu/gutil/bits.h:19:42: runtime error: unsigned integer overflow:
        134678536 * 16843009 cannot be represented in type 'unsigned int'
          #0 0xffffa1ebd8d4 in Bits::CountOnes(unsigned int) 
src/kudu/gutil/bits.h:19:42
          #1 0xffffa1ebd830 in Bits::CountOnes64(unsigned long) 
src/kudu/gutil/bits.h:30:12
          #2 0xffffa1ebd7f8 in Bits::CountOnes64withPopcount(unsigned long) 
src/kudu/gutil/bits.h:43:12
    
      SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior 
src/kudu/gutil/bits.h:19:42
    
    This patch addresses the issue.
    
    Change-Id: I47bff62676ee57706d6b5ef841e3891bba5a62fa
    Reviewed-on: http://gerrit.cloudera.org:8080/20558
    Reviewed-by: Marton Greber <greber...@gmail.com>
    Tested-by: Alexey Serbin <ale...@apache.org>
    Reviewed-by: Abhishek Chennaka <achenn...@cloudera.com>
---
 src/kudu/gutil/bits.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/kudu/gutil/bits.h b/src/kudu/gutil/bits.h
index b4a4327b5..1c3c71417 100644
--- a/src/kudu/gutil/bits.h
+++ b/src/kudu/gutil/bits.h
@@ -16,7 +16,7 @@ class Bits {
   static int CountOnes(uint32 n) {
     n -= ((n >> 1) & 0x55555555);
     n = ((n >> 2) & 0x33333333) + (n & 0x33333333);
-    return (((n + (n >> 4)) & 0xF0F0F0F) * 0x1010101) >> 24;
+    return static_cast<int>((((n + (n >> 4)) & 0xF0F0F0FULL) * 0x1010101ULL) 
>> 24);
   }
 
   // Count bits using sideways addition [WWG'57]. See Knuth TAOCP v4 7.1.3(59)