[clang-tools-extra] e855fea - [clang-tidy] fix bugprone-sizeof-expression when sizeof expression with template types (#115275)

[via cfe-commits]

Author: Congcong Cai
Date: 2024-11-12T11:36:33+08:00
New Revision: e855feac41fd89aebf540a155d21f12a3e82f05b

URL: https://github.com/llvm/llvm-project/commit/e855feac41fd89aebf540a155d21f12a3e82f05b
DIFF: https://github.com/llvm/llvm-project/commit/e855feac41fd89aebf540a155d21f12a3e82f05b.diff

LOG: [clang-tidy] fix bugprone-sizeof-expression when sizeof expression with template types (#115275)

Fixed: #115175.
`dependent type` are not the same even pointers are the same.

---------

Co-authored-by: whisperity <whisperity at gmail.com>

Added: 
    

Modified: 
    clang-tools-extra/clang-tidy/bugprone/SizeofExpressionCheck.cpp
    clang-tools-extra/docs/ReleaseNotes.rst
    clang-tools-extra/test/clang-tidy/checkers/bugprone/sizeof-expression.cpp

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clang-tidy/bugprone/SizeofExpressionCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/SizeofExpressionCheck.cpp
index 628d30ce7f73fe..f3d4c2255d86ec 100644
--- a/clang-tools-extra/clang-tidy/bugprone/SizeofExpressionCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/SizeofExpressionCheck.cpp
@@ -400,7 +400,9 @@ void SizeofExpressionCheck::check(const MatchFinder::MatchResult &Result) {
            "suspicious usage of 'sizeof(array)/sizeof(...)';"
            " denominator 
diff ers from the size of array elements")
           << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
-    } else if (NumTy && DenomTy && NumTy == DenomTy) {
+    } else if (NumTy && DenomTy && NumTy == DenomTy &&
+               !NumTy->isDependentType()) {
+      // Dependent type should not be compared.
       diag(E->getOperatorLoc(),
            "suspicious usage of 'sizeof(...)/sizeof(...)'; both expressions "
            "have the same type")

diff  --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 442fb7180555ea..db971f08ca3dbc 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -175,7 +175,8 @@ Changes in existing checks
 - Improved :doc:`bugprone-sizeof-expression
   <clang-tidy/checks/bugprone/sizeof-expression>` check to find suspicious
   usages of ``sizeof()``, ``alignof()``, and ``offsetof()`` when adding or
-  subtracting from a pointer directly or when used to scale a numeric value.
+  subtracting from a pointer directly or when used to scale a numeric value and
+  fix false positive when sizeof expression with template types.
 
 - Improved :doc:`bugprone-throw-keyword-missing
   <clang-tidy/checks/bugprone/throw-keyword-missing>` by fixing a false positive

diff  --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/sizeof-expression.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/sizeof-expression.cpp
index 81efd87345c97e..5e6f394152e9d1 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/sizeof-expression.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/sizeof-expression.cpp
@@ -385,3 +385,10 @@ int ValidExpressions() {
   sum += sizeof(PtrArray) / sizeof(A[0]);
   return sum;
 }
+
+namespace gh115175 {
+template<class T>
+int ValidateTemplateTypeExpressions(T t) {
+  return sizeof(t.val) / sizeof(t.val[0]);
+}
+} // namespace gh115175