Add documentation for the newly introduced CheckOption for loop.

Author: MalavikaSamak

clang-tools-extra/clang-tidy/bugprone/SizeofExpressionCheck.cpp

@@ -73,7 +73,7 @@ SizeofExpressionCheck::SizeofExpressionCheck(StringRef Name,
       WarnOnSizeOfPointer(Options.get("WarnOnSizeOfPointer", false)),
       WarnOnOffsetDividedBySizeOf(
           Options.get("WarnOnOffsetDividedBySizeOf", true)),
-      WarnOnLoopExprSizeOf(Options.get("WarnOnLoopExprSizeOf", true)) {}
+      WarnOnSizeOfInLoopTermination(Options.get("WarnOnSizeOfInLoopTermination", true)) {}
 
 void SizeofExpressionCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "WarnOnSizeOfConstant", WarnOnSizeOfConstant);
@@ -87,7 +87,7 @@ void SizeofExpressionCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "WarnOnSizeOfPointer", WarnOnSizeOfPointer);
   Options.store(Opts, "WarnOnOffsetDividedBySizeOf",
                 WarnOnOffsetDividedBySizeOf);
-  Options.store(Opts, "WarnOnLoopExprSizeOf", WarnOnLoopExprSizeOf);
+  Options.store(Opts, "WarnOnSizeOfInLoopTermination", WarnOnSizeOfInLoopTermination);
 }
 
 void SizeofExpressionCheck::registerMatchers(MatchFinder *Finder) {
@@ -137,9 +137,9 @@ void SizeofExpressionCheck::registerMatchers(MatchFinder *Finder) {
                        this);
   }
 
-  if (WarnOnLoopExprSizeOf) {
+  if (WarnOnSizeOfInLoopTermination) {
     Finder->addMatcher(
-        LoopExpr(has(binaryOperator(has(SizeOfExpr)))).bind("loop-expr"), this);
+        LoopExpr(has(binaryOperator(has(SizeOfExpr.bind("loop-expr"))))), this);
   }
 
   // Detect sizeof(kPtr) where kPtr is 'const char* kPtr = "abc"';

clang-tools-extra/clang-tidy/bugprone/SizeofExpressionCheck.h

@@ -32,7 +32,7 @@ class SizeofExpressionCheck : public ClangTidyCheck {
   const bool WarnOnSizeOfPointerToAggregate;
   const bool WarnOnSizeOfPointer;
   const bool WarnOnOffsetDividedBySizeOf;
-  const bool WarnOnLoopExprSizeOf;
+  const bool WarnOnSizeOfInLoopTermination;
 };
 
 } // namespace clang::tidy::bugprone

clang-tools-extra/docs/clang-tidy/checks/bugprone/sizeof-expression.rst

@@ -316,3 +316,11 @@ Options
    When `true`, the check will warn on pointer arithmetic where the
    element count is obtained from a division with ``sizeof(...)``,
    e.g., ``Ptr + Bytes / sizeof(*T)``. Default is `true`.
+
+.. option:: WarnOnSizeOfInLoopTermination
+
+   When `true`, the check will warn about incorrect use of sizeof expression
+   in loop termination condition. The warning triggers if the sizeof expression
+   appears to be incorrectly used to determine the number of array/buffer elements.
+   e.g, ``long arr[10]; for(int i = 0; i < sizeof(arr); i++) { ... }. Default
+  is `true`.

clang-tools-extra/test/clang-tidy/checkers/bugprone/sizeof-expression.cpp

@@ -174,7 +174,7 @@ struct B {
 
 int square(int num, struct B b) {
     struct A arr[10];
-    // CHECK-MESSAGES: :[[@LINE+1]]:5: warning: suspicious usage of 'sizeof' in the loop [bugprone-sizeof-expression]
+    // CHECK-MESSAGES: :[[@LINE+1]]:24: warning: suspicious usage of 'sizeof' in the loop [bugprone-sizeof-expression]
     for(int i = 0; i < sizeof(arr); i++) {
        struct A a = arr[i];
     }
@@ -188,7 +188,7 @@ int square(int num, struct B b) {
        struct A a = arr[i];
     }
 
-    // CHECK-MESSAGES: :[[@LINE+1]]:5: warning: suspicious usage of 'sizeof' in the loop [bugprone-sizeof-expression]
+    // CHECK-MESSAGES: :[[@LINE+1]]:24: warning: suspicious usage of 'sizeof' in the loop [bugprone-sizeof-expression]
     for(int j = 0; j < sizeof(b.a); j++) {
 
     }