[compiler-rt] [hwasan] Fix DCHECK with COMPILER_RT_DEBUG=ON (PR #84612)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Alexander Richardson (arichardson)

<details>
<summary>Changes</summary>

It appears this assertion should actually be checking that the pointer
is aligned to `sz` bytes rather than the shadow alignment, since
otherwise the `(ptr & (kShadowAlignment - 1))` mask would always be 0.


---
Full diff: https://github.com/llvm/llvm-project/pull/84612.diff


1 Files Affected:

- (modified) compiler-rt/lib/hwasan/hwasan_checks.h (+1-1) 


``````````diff
diff --git a/compiler-rt/lib/hwasan/hwasan_checks.h b/compiler-rt/lib/hwasan/hwasan_checks.h
index 0911af30dcb8fc..7067e7140e7bef 100644
--- a/compiler-rt/lib/hwasan/hwasan_checks.h
+++ b/compiler-rt/lib/hwasan/hwasan_checks.h
@@ -140,7 +140,7 @@ __attribute__((always_inline, nodebug)) static inline uptr ShortTagSize(
 
 __attribute__((always_inline, nodebug)) static inline bool
 PossiblyShortTagMatches(tag_t mem_tag, uptr ptr, uptr sz) {
-  DCHECK(IsAligned(ptr, kShadowAlignment));
+  DCHECK(IsAligned(ptr, sz));
   tag_t ptr_tag = GetTagFromPointer(ptr);
   if (ptr_tag == mem_tag)
     return true;

``````````

</details>


https://github.com/llvm/llvm-project/pull/84612