[clang-tidy] Warn about arrays in `bugprone-undefined-memory-manipulation`

[fwolff]

Summary

Fixes issue #55579.

[JonasToth]

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

27–34

you can factor the hasDeclaration(cxxRecordDecl(isNotTriviallyCopyable())) out to avoid the copy&paste.

clang-tools-extra/test/clang-tidy/checkers/bugprone-undefined-memory-manipulation.cpp

129

could you please add a test with a typedef to array to ensure that those are matched as well.

[LegalizeAdulthood]

Clang-Tidy tests and docs have moved to module subdirectories.

Please rebase this onto main:HEAD and:

• fold your changes into the appropriate subdirs, stripping the module prefix from new files.
• make the target check-clang-extra to validate your tests
• make the target docs-clang-tools-html to validate any docs changes

[PiotrZSL]

LGTM, I will rebase, push it and add release notes.

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

 namespace {
 AST_MATCHER(CXXRecordDecl, isNotTriviallyCopyable) {
   // For incomplete types, assume they are TriviallyCopyable.
   return Node.hasDefinition() ? !Node.isTriviallyCopyable() : false;
 }
 } // namespace
 
 void UndefinedMemoryManipulationCheck::registerMatchers(MatchFinder *Finder) {
-  const auto NotTriviallyCopyableObject =
-      hasType(ast_matchers::hasCanonicalType(
-          pointsTo(cxxRecordDecl(isNotTriviallyCopyable()))));
+  const auto HasNotTriviallyCopyableDecl =
+      hasDeclaration(cxxRecordDecl(isNotTriviallyCopyable()));
+  const auto ArrayOfNotTriviallyCopyable =
+      arrayType(hasElementType(HasNotTriviallyCopyableDecl));
+  const auto NotTriviallyCopyableObject = hasType(hasCanonicalType(
+      anyOf(pointsTo(qualType(anyOf(HasNotTriviallyCopyableDecl,
+                                    ArrayOfNotTriviallyCopyable))),
+            ArrayOfNotTriviallyCopyable)));
 
   // Check whether destination object is not TriviallyCopyable.
   // Applicable to all three memory manipulation functions.
   Finder->addMatcher(callExpr(callee(functionDecl(hasAnyName(
                                   "::memset", "::memcpy", "::memmove"))),
                               hasArgument(0, NotTriviallyCopyableObject))
                          .bind("dest"),
                      this);

clang-tools-extra/test/clang-tidy/checkers/bugprone-undefined-memory-manipulation.cpp

void notTriviallyCopyable() {
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'types::Destruct'
   memmove(&p, &c, sizeof(int));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, source object type 'types::Copy'
   std::memmove(&p, &m, sizeof(int));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, source object type 'types::Move'
   ::memmove(&p, &vb, sizeof(int));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, source object type 'types::VirtualBase'
 
+  types::Copy ca[10];
+  memset(ca, 0, sizeof(ca));
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'types::Copy[10]'
+  memset(&ca, 0, sizeof(ca));
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'types::Copy[10]'
+
 #define MEMSET memset(&vf, 0, sizeof(int));
   MEMSET
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'types::VirtualFunc'
 #define MEMCPY memcpy(&d, &p, sizeof(int));
   MEMCPY
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'types::Destruct'
 #define MEMMOVE memmove(&p, &c, sizeof(int));
   MEMMOVE
#define MEMMOVE memmove(&p, &c, sizeof(int));
   PCopy2 pc2;
   PCopy3 pc3;
   memset(&c3, 0, sizeof(int));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'Copy3'
   memset(pc2, 0, sizeof(int));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'aliases::Copy2'
   memset(pc3, 0, sizeof(int));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'Copy3'
+
+  using Copy3Arr = Copy3[5];
+  Copy3Arr c3a;
+  memset(c3a, 0, sizeof(c3a));
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'Copy3Arr'
+  memset(&c3a, 0, sizeof(c3a));
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'Copy3Arr'
+
+  typedef Copy3 Copy3Arr2[5];
+  Copy3Arr2 c3a2;
+  memset(c3a2, 0, sizeof(c3a2));
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: undefined behavior, destination object type 'Copy3Arr2'
 }
 
 void triviallyCopyable() {
   types::Plain p;
   types::Base base;
   types::Derived derived;
 
   int i = 5;