[clang-tidy] Add option "LiteralInitializers" to cppcoreguidelines-pro-type-member-init

Differential Revision: D24892

llvm-svn: 361601

clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp

@@ -250,7 +250,8 @@ void fixInitializerList(const ASTContext &Context, DiagnosticBuilder &Diag,
 ProTypeMemberInitCheck::ProTypeMemberInitCheck(StringRef Name,
                                                ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
-      IgnoreArrays(Options.get("IgnoreArrays", false)) {}
+      IgnoreArrays(Options.get("IgnoreArrays", false)),
+      UseAssignment(Options.getLocalOrGlobal("UseAssignment", false)) {}
 
 void ProTypeMemberInitCheck::registerMatchers(MatchFinder *Finder) {
   if (!getLangOpts().CPlusPlus)
@@ -314,6 +315,7 @@ void ProTypeMemberInitCheck::check(const MatchFinder::MatchResult &Result) {
 
 void ProTypeMemberInitCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "IgnoreArrays", IgnoreArrays);
+  Options.store(Opts, "UseAssignment", UseAssignment);
 }
 
 // FIXME: Copied from clang/lib/Sema/SemaDeclCXX.cpp.
@@ -338,6 +340,56 @@ static bool isEmpty(ASTContext &Context, const QualType &Type) {
   return isIncompleteOrZeroLengthArrayType(Context, Type);
 }
 
+static const char *getInitializer(QualType QT, bool UseAssignment) {
+  const char *DefaultInitializer = "{}";
+  if (!UseAssignment)
+    return DefaultInitializer;
+
+  if (QT->isPointerType())
+    return " = nullptr";
+
+  const BuiltinType *BT =
+      dyn_cast<BuiltinType>(QT.getCanonicalType().getTypePtr());
+  if (!BT)
+    return DefaultInitializer;
+
+  switch (BT->getKind()) {
+  case BuiltinType::Bool:
+    return " = false";
+  case BuiltinType::Float:
+    return " = 0.0F";
+  case BuiltinType::Double:
+    return " = 0.0";
+  case BuiltinType::LongDouble:
+    return " = 0.0L";
+  case BuiltinType::SChar:
+  case BuiltinType::Char_S:
+  case BuiltinType::WChar_S:
+  case BuiltinType::Char16:
+  case BuiltinType::Char32:
+  case BuiltinType::Short:
+  case BuiltinType::Int:
+    return " = 0";
+  case BuiltinType::UChar:
+  case BuiltinType::Char_U:
+  case BuiltinType::WChar_U:
+  case BuiltinType::UShort:
+  case BuiltinType::UInt:
+    return " = 0U";
+  case BuiltinType::Long:
+    return " = 0L";
+  case BuiltinType::ULong:
+    return " = 0UL";
+  case BuiltinType::LongLong:
+    return " = 0LL";
+  case BuiltinType::ULongLong:
+    return " = 0ULL";
+
+  default:
+    return DefaultInitializer;
+  }
+}
+
 void ProTypeMemberInitCheck::checkMissingMemberInitializer(
     ASTContext &Context, const CXXRecordDecl &ClassDecl,
     const CXXConstructorDecl *Ctor) {
@@ -420,7 +472,7 @@ void ProTypeMemberInitCheck::checkMissingMemberInitializer(
     for (const FieldDecl *Field : FieldsToFix) {
       Diag << FixItHint::CreateInsertion(
           getLocationForEndOfToken(Context, Field->getSourceRange().getEnd()),
-          "{}");
+          getInitializer(Field->getType(), UseAssignment));
     }
   } else if (Ctor) {
     // Otherwise, rewrite the constructor's initializer list.

clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.h

@@ -64,6 +64,11 @@ private:
 
   // Whether arrays need to be initialized or not. Default is false.
   bool IgnoreArrays;
+
+  // Whether fix-its for initialization of fundamental type use assignment
+  // instead of brace initalization. Only effective in C++11 mode. Default is
+  // false.
+  bool UseAssignment;
 };
 
 } // namespace cppcoreguidelines

clang-tools-extra/docs/ReleaseNotes.rst

@@ -186,6 +186,11 @@ Improvements to clang-tidy
   `WarnOnLargeObject` and `MaxSize` options to warn on any large trivial
   object caught by value.
 
+- Added `UseAssignment` option to :doc:`cppcoreguidelines-pro-type-member-init`
+
+  If set to true, the check will provide fix-its with literal initializers
+  (``int i = 0;``) instead of curly braces (``int i{};``).
+
 Improvements to include-fixer
 -----------------------------
 

clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines-pro-type-member-init.rst

@@ -33,6 +33,10 @@ Options
    zero-initialized during construction. For performance critical code, it may
    be important to not initialize fixed-size array members. Default is `0`.
 
+.. option:: UseAssignment
+   If set to non-zero, the check will provide fix-its with literal initializers
+   (``int i = 0;``) instead of curly braces (``int i{};``).
+
 This rule is part of the "Type safety" profile of the C++ Core
 Guidelines, corresponding to rule Type.6. See
 https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-type-memberinit.

clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-type-member-init-use-assignment.cpp

@@ -0,0 +1,40 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-pro-type-member-init %t -- -config="{CheckOptions: [{key: "cppcoreguidelines-pro-type-member-init.UseAssignment", value: 1}]}" -- -std=c++11
+
+struct T {
+  int i;
+};
+
+struct S {
+  bool b;
+  // CHECK-FIXES: bool b = false;
+  char c;
+  // CHECK-FIXES: char c = 0;
+  signed char sc;
+  // CHECK-FIXES: signed char sc = 0;
+  unsigned char uc;
+  // CHECK-FIXES: unsigned char uc = 0U;
+  int i;
+  // CHECK-FIXES: int i = 0;
+  unsigned u;
+  // CHECK-FIXES: unsigned u = 0U;
+  long l;
+  // CHECK-FIXES: long l = 0L;
+  unsigned long ul;
+  // CHECK-FIXES: unsigned long ul = 0UL;
+  long long ll;
+  // CHECK-FIXES: long long ll = 0LL;
+  unsigned long long ull;
+  // CHECK-FIXES: unsigned long long ull = 0ULL;
+  float f;
+  // CHECK-FIXES: float f = 0.0F;
+  double d;
+  // CHECK-FIXES: double d = 0.0;
+  long double ld;
+  // CHECK-FIXES: double ld = 0.0L;
+  int *ptr;
+  // CHECK-FIXES: int *ptr = nullptr;
+  T t;
+  // CHECK-FIXES: T t{};
+  S() {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these fields:
+};