[clang] Fix remove{CVR|Fast}Qualifiers with 64-bit Qualifiers::Mask

[kovdan01]

After #84384, Qualifiers::Mask becomes 64-bit. So, operations like Mask &= ~U32 where U32 is unsigned produce undesirable results since higher 32 bits of Mask become zeroed while they should be preserved. Fix that by explicitly casting unsigned values to uint64_t in such operations. Signatures of fixed functions are intentionally left intact instead of changing the argument itself to uint64_t to keep things consistent with other functions working with the same qualifiers and to emphasize that 64-bit masks should not be used for these types of qualifiers.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Daniil Kovalev (kovdan01)

Changes

After #84384, Qualifiers::Mask becomes 64-bit. So, operations like Mask &= ~U32 where U32 is unsigned produce undesirable results since higher 32 bits of Mask become zeroed while they should be preserved. Fix that by explicitly casting unsigned values to uint64_t in such operations. Signatures of fixed functions are intentionally left intact instead of changing the argument itself to uint64_t to keep things consistent with other functions working with the same qualifiers and to emphasize that 64-bit masks should not be used for these types of qualifiers.

---

Full diff: https://github.com/llvm/llvm-project/pull/90329.diff

1 Files Affected:

• (modified) clang/include/clang/AST/Type.h (+2-2)

diff --git a/clang/include/clang/AST/Type.h b/clang/include/clang/AST/Type.h
index dff02d4861b3db..5c7d5396658b57 100644
--- a/clang/include/clang/AST/Type.h
+++ b/clang/include/clang/AST/Type.h
@@ -480,7 +480,7 @@ class Qualifiers {
   }
   void removeCVRQualifiers(unsigned mask) {
     assert(!(mask & ~CVRMask) && "bitmask contains non-CVR bits");
-    Mask &= ~mask;
+    Mask &= ~static_cast<uint64_t>(mask);
   }
   void removeCVRQualifiers() {
     removeCVRQualifiers(CVRMask);
@@ -609,7 +609,7 @@ class Qualifiers {
   }
   void removeFastQualifiers(unsigned mask) {
     assert(!(mask & ~FastMask) && "bitmask contains non-fast qualifier bits");
-    Mask &= ~mask;
+    Mask &= ~static_cast<uint64_t>(mask);
   }
   void removeFastQualifiers() {
     removeFastQualifiers(FastMask);

[rjmccall]

LGTM

[kovdan01]

@AaronBallman Please let me know if you have some comments on this or if can be merged

[cor3ntin]

@kovdan01 Aaron is not available this week. This looks sensible. Do you need me to merge it for you?

[kovdan01]

@cor3ntin Thanks for feedback! I'll merge it myself