[PATCH] D126186: [clang-tidy] Extend cert-oop57-cpp to check non-zero memset values

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Clang Tidy check cert-oop57-cpp now checks for arbitrary-valued integer
literals in memset expressions containing non-trivially
default-constructible instances. Previously it only checked 0 values.

Note that the first non-compliant example of
https://wiki.sei.cmu.edu/confluence/display/cplusplus/OOP57-CPP.+Prefer+special+member+functions+and+overloaded+operators+to+C+Standard+Library+functions requires this.

A comparative analysis of OS projects is currently running to see the impact of this change.


https://reviews.llvm.org/D126186

Files:
  clang-tools-extra/clang-tidy/cert/NonTrivialTypesLibcMemoryCallsCheck.cpp
  clang-tools-extra/test/clang-tidy/checkers/cert-oop57-cpp.cpp


Index: clang-tools-extra/test/clang-tidy/checkers/cert-oop57-cpp.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/cert-oop57-cpp.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/cert-oop57-cpp.cpp
@@ -88,3 +88,10 @@
   mymemcmp(&Data, &Other, sizeof(Data));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: consider using comparison operators instead of calling 'mymemcmp'
 }
+
+void nonNullSetValue() {
+  NonTrivial Data;
+  // Check non-null-valued second argument.
+  std::memset(&Data, 1, sizeof(Data));
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: calling 'memset' on a non-trivially default constructible class is undefined
+}
Index: clang-tools-extra/clang-tidy/cert/NonTrivialTypesLibcMemoryCallsCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/cert/NonTrivialTypesLibcMemoryCallsCheck.cpp
+++ clang-tools-extra/clang-tidy/cert/NonTrivialTypesLibcMemoryCallsCheck.cpp
@@ -90,7 +90,7 @@
       callExpr(callee(namedDecl(hasAnyName(
                    utils::options::parseListPair(BuiltinMemSet, MemSetNames)))),
                ArgChecker(unless(isTriviallyDefaultConstructible()),
-                          expr(integerLiteral(equals(0)))))
+                          expr(integerLiteral())))
           .bind("lazyConstruct"),
       this);
   Finder->addMatcher(


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