add option

Author: HerrCai0907

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

@@ -33,6 +33,16 @@ AST_MATCHER(Type, isChar) {
 
 } // namespace
 
+UnintendedCharOstreamOutputCheck::UnintendedCharOstreamOutputCheck(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context), CastTypeName(Options.get("CastTypeName")) {
+}
+void UnintendedCharOstreamOutputCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  if (CastTypeName.has_value())
+    Options.store(Opts, "CastTypeName", CastTypeName.value());
+}
+
 void UnintendedCharOstreamOutputCheck::registerMatchers(MatchFinder *Finder) {
   auto BasicOstream =
       cxxRecordDecl(hasName("::std::basic_ostream"),
@@ -60,19 +70,17 @@ void UnintendedCharOstreamOutputCheck::check(
   DiagnosticBuilder Builder =
       diag(Call->getOperatorLoc(),
            "%0 passed to 'operator<<' outputs as character instead of integer. "
-           "cast to 'unsigned' to print numeric value or cast to 'char' to "
-           "print "
-           "as character")
+           "cast to 'unsigned int' to print numeric value or cast to 'char' to "
+           "print as character")
       << Value->getType() << SourceRange;
 
   QualType T = Value->getType();
   const Type *UnqualifiedDesugaredType = T->getUnqualifiedDesugaredType();
 
-  llvm::StringRef CastType;
-  if (UnqualifiedDesugaredType->isSpecificBuiltinType(BuiltinType::SChar))
-    CastType = "int";
-  else
-    CastType = "unsigned int";
+  llvm::StringRef CastType = CastTypeName.value_or(
+      UnqualifiedDesugaredType->isSpecificBuiltinType(BuiltinType::SChar)
+          ? "int"
+          : "unsigned int");
 
   Builder << FixItHint::CreateReplacement(
       SourceRange, ("static_cast<" + CastType + ">(" +

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

@@ -10,6 +10,7 @@
 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_UNINTENDEDCHAROSTREAMOUTPUTCHECK_H
 
 #include "../ClangTidyCheck.h"
+#include <optional>
 
 namespace clang::tidy::bugprone {
 
@@ -20,13 +21,16 @@ namespace clang::tidy::bugprone {
 /// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/unintended-char-ostream-output.html
 class UnintendedCharOstreamOutputCheck : public ClangTidyCheck {
 public:
-  UnintendedCharOstreamOutputCheck(StringRef Name, ClangTidyContext *Context)
-      : ClangTidyCheck(Name, Context) {}
+  UnintendedCharOstreamOutputCheck(StringRef Name, ClangTidyContext *Context);
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
     return LangOpts.CPlusPlus;
   }
+
+private:
+  const std::optional<StringRef> CastTypeName;
 };
 
 } // namespace clang::tidy::bugprone

clang-tools-extra/docs/clang-tidy/checks/bugprone/unintended-char-ostream-output.rst

@@ -14,17 +14,22 @@ integer values.
 
 .. code-block:: c++
 
-    uint8_t v = 65;
-    std::cout << v; // output 'A' instead of '65'
+  uint8_t v = 65;
+  std::cout << v; // output 'A' instead of '65'
 
 It could be fixed as
 
 .. code-block:: c++
 
-    std::cout << static_cast<uint32_t>(v);
+  std::cout << static_cast<uint32_t>(v);
 
 Or cast to char to explicitly indicate the intent
 
 .. code-block:: c++
 
-    std::cout << static_cast<char>(v);
+  std::cout << static_cast<char>(v);
+
+.. option:: CastTypeName
+
+  When `CastTypeName` is specified, the fix-it will use `CastTypeName` as the
+  cast target type. Otherwise, fix-it will automatically infer the type.

clang-tools-extra/test/clang-tidy/checkers/bugprone/unintended-char-ostream-output-cast-type.cpp

@@ -0,0 +1,45 @@
+// RUN: %check_clang_tidy %s bugprone-unintended-char-ostream-output %t -- \
+// RUN:   -config="{CheckOptions: \
+// RUN:             {bugprone-unintended-char-ostream-output.CastTypeName: "uint8_t"}}"
+
+namespace std {
+
+template <class _CharT, class _Traits = void> class basic_ostream {
+public:
+  basic_ostream &operator<<(int);
+  basic_ostream &operator<<(unsigned int);
+};
+
+template <class CharT, class Traits>
+basic_ostream<CharT, Traits> &operator<<(basic_ostream<CharT, Traits> &, CharT);
+template <class CharT, class Traits>
+basic_ostream<CharT, Traits> &operator<<(basic_ostream<CharT, Traits> &, char);
+template <class _Traits>
+basic_ostream<char, _Traits> &operator<<(basic_ostream<char, _Traits> &, char);
+template <class _Traits>
+basic_ostream<char, _Traits> &operator<<(basic_ostream<char, _Traits> &,
+                                          signed char);
+template <class _Traits>
+basic_ostream<char, _Traits> &operator<<(basic_ostream<char, _Traits> &,
+                                          unsigned char);
+
+using ostream = basic_ostream<char>;
+
+} // namespace std
+
+class A : public std::ostream {};
+
+void origin_ostream(std::ostream &os) {
+  unsigned char unsigned_value = 9;
+  os << unsigned_value;
+  // CHECK-MESSAGES: [[@LINE-1]]:6: warning: 'unsigned char' passed to 'operator<<' outputs as character instead of integer
+  // CHECK-FIXES: os << static_cast<uint8_t>(unsigned_value);
+
+  signed char signed_value = 9;
+  os << signed_value;
+  // CHECK-MESSAGES: [[@LINE-1]]:6: warning: 'signed char' passed to 'operator<<' outputs as character instead of integer
+  // CHECK-FIXES: os << static_cast<uint8_t>(signed_value);
+
+  char char_value = 9;
+  os << char_value;
+}