[clang] Use StringRef::operator== instead of StringRef::equals (NFC) (#91844)

I'm planning to remove StringRef::equals in favor of
StringRef::operator==.

- StringRef::operator==/!= outnumber StringRef::equals by a factor of
  24 under clang/ in terms of their usage.

- The elimination of StringRef::equals brings StringRef closer to
  std::string_view, which has operator== but not equals.

- S == "foo" is more readable than S.equals("foo"), especially for
  !Long.Expression.equals("str") vs Long.Expression != "str".

Author: kazutakahirata

clang/include/clang/Basic/IdentifierTable.h

@@ -738,7 +738,7 @@ class IdentifierTable {
     II->Entry = &Entry;
 
     // If this is the 'import' contextual keyword, mark it as such.
-    if (Name.equals("import"))
+    if (Name == "import")
       II->setModulesImport(true);
 
     return *II;

clang/include/clang/Basic/SourceManager.h

@@ -1504,7 +1504,7 @@ class SourceManager : public RefCountedBase<SourceManager> {
     if (Presumed.isInvalid())
       return false;
     StringRef Filename(Presumed.getFilename());
-    return Filename.equals("<built-in>");
+    return Filename == "<built-in>";
   }
 
   /// Returns whether \p Loc is located in a <command line> file.
@@ -1513,7 +1513,7 @@ class SourceManager : public RefCountedBase<SourceManager> {
     if (Presumed.isInvalid())
       return false;
     StringRef Filename(Presumed.getFilename());
-    return Filename.equals("<command line>");
+    return Filename == "<command line>";
   }
 
   /// Returns whether \p Loc is located in a <scratch space> file.
@@ -1522,7 +1522,7 @@ class SourceManager : public RefCountedBase<SourceManager> {
     if (Presumed.isInvalid())
       return false;
     StringRef Filename(Presumed.getFilename());
-    return Filename.equals("<scratch space>");
+    return Filename == "<scratch space>";
   }
 
   /// Returns if a SourceLocation is in a system header.

clang/lib/ARCMigrate/ObjCMT.cpp

@@ -484,7 +484,7 @@ static void rewriteToObjCProperty(const ObjCMethodDecl *Getter,
 
   // Short circuit 'delegate' properties that contain the name "delegate" or
   // "dataSource", or have exact name "target" to have 'assign' attribute.
-  if (PropertyName.equals("target") || PropertyName.contains("delegate") ||
+  if (PropertyName == "target" || PropertyName.contains("delegate") ||
       PropertyName.contains("dataSource")) {
     QualType QT = Getter->getReturnType();
     if (!QT->isRealType())

clang/lib/AST/PrintfFormatString.cpp

@@ -146,13 +146,13 @@ static PrintfSpecifierResult ParsePrintfSpecifier(FormatStringHandler &H,
           if (Warn && (Size == 0 || Size > 8))
             H.handleInvalidMaskType(MaskType);
           FS.setMaskType(MaskType);
-        } else if (MatchedStr.equals("sensitive"))
+        } else if (MatchedStr == "sensitive")
           PrivacyFlags = clang::analyze_os_log::OSLogBufferItem::IsSensitive;
         else if (PrivacyFlags !=
-                 clang::analyze_os_log::OSLogBufferItem::IsSensitive &&
-                 MatchedStr.equals("private"))
+                     clang::analyze_os_log::OSLogBufferItem::IsSensitive &&
+                 MatchedStr == "private")
           PrivacyFlags = clang::analyze_os_log::OSLogBufferItem::IsPrivate;
-        else if (PrivacyFlags == 0 && MatchedStr.equals("public"))
+        else if (PrivacyFlags == 0 && MatchedStr == "public")
           PrivacyFlags = clang::analyze_os_log::OSLogBufferItem::IsPublic;
       } else {
         size_t CommaOrBracePos =

clang/lib/ASTMatchers/Dynamic/Marshallers.cpp

@@ -21,7 +21,7 @@ getBestGuess(llvm::StringRef Search, llvm::ArrayRef<llvm::StringRef> Allowed,
   llvm::StringRef Res;
   for (const llvm::StringRef &Item : Allowed) {
     if (Item.equals_insensitive(Search)) {
-      assert(!Item.equals(Search) && "This should be handled earlier on.");
+      assert(Item != Search && "This should be handled earlier on.");
       MaxEditDistance = 1;
       Res = Item;
       continue;
@@ -41,7 +41,7 @@ getBestGuess(llvm::StringRef Search, llvm::ArrayRef<llvm::StringRef> Allowed,
       if (!NoPrefix.consume_front(DropPrefix))
         continue;
       if (NoPrefix.equals_insensitive(Search)) {
-        if (NoPrefix.equals(Search))
+        if (NoPrefix == Search)
           return Item.str();
         MaxEditDistance = 1;
         Res = Item;

clang/lib/Basic/Builtins.cpp

@@ -64,7 +64,7 @@ bool Builtin::Context::isBuiltinFunc(llvm::StringRef FuncName) {
   bool InStdNamespace = FuncName.consume_front("std-");
   for (unsigned i = Builtin::NotBuiltin + 1; i != Builtin::FirstTSBuiltin;
        ++i) {
-    if (FuncName.equals(BuiltinInfo[i].Name) &&
+    if (FuncName == BuiltinInfo[i].Name &&
         (bool)strchr(BuiltinInfo[i].Attributes, 'z') == InStdNamespace)
       return strchr(BuiltinInfo[i].Attributes, 'f') != nullptr;
   }

clang/lib/Basic/Diagnostic.cpp

@@ -851,8 +851,7 @@ FormatDiagnostic(const char *DiagStr, const char *DiagEnd,
   // When the diagnostic string is only "%0", the entire string is being given
   // by an outside source.  Remove unprintable characters from this string
   // and skip all the other string processing.
-  if (DiagEnd - DiagStr == 2 &&
-      StringRef(DiagStr, DiagEnd - DiagStr).equals("%0") &&
+  if (DiagEnd - DiagStr == 2 && StringRef(DiagStr, DiagEnd - DiagStr) == "%0" &&
       getArgKind(0) == DiagnosticsEngine::ak_std_string) {
     const std::string &S = getArgStdStr(0);
     EscapeStringForDiagnostic(S, OutStr);

clang/lib/Basic/LangOptions.cpp

@@ -48,7 +48,7 @@ void LangOptions::resetNonModularOptions() {
 
 bool LangOptions::isNoBuiltinFunc(StringRef FuncName) const {
   for (unsigned i = 0, e = NoBuiltinFuncs.size(); i != e; ++i)
-    if (FuncName.equals(NoBuiltinFuncs[i]))
+    if (FuncName == NoBuiltinFuncs[i])
       return true;
   return false;
 }

clang/lib/Basic/Targets/ARM.cpp

@@ -173,8 +173,7 @@ bool ARMTargetInfo::supportsThumb() const {
 }
 
 bool ARMTargetInfo::supportsThumb2() const {
-  return CPUAttr.equals("6T2") ||
-         (ArchVersion >= 7 && !CPUAttr.equals("8M_BASE"));
+  return CPUAttr == "6T2" || (ArchVersion >= 7 && CPUAttr != "8M_BASE");
 }
 
 StringRef ARMTargetInfo::getCPUAttr() const {
@@ -1162,7 +1161,7 @@ bool ARMTargetInfo::validateAsmConstraint(
     return true;
   case 'j': // An immediate integer between 0 and 65535 (valid for MOVW)
     // only available in ARMv6T2 and above
-    if (CPUAttr.equals("6T2") || ArchVersion >= 7) {
+    if (CPUAttr == "6T2" || ArchVersion >= 7) {
       Info.setRequiresImmediate(0, 65535);
       return true;
     }

clang/lib/Basic/Targets/PPC.h

@@ -360,7 +360,7 @@ class LLVM_LIBRARY_VISIBILITY PPCTargetInfo : public TargetInfo {
   bool hasBitIntType() const override { return true; }
 
   bool isSPRegName(StringRef RegName) const override {
-    return RegName.equals("r1") || RegName.equals("x1");
+    return RegName == "r1" || RegName == "x1";
   }
 
   // We support __builtin_cpu_supports/__builtin_cpu_is on targets that