Add basic support for c++20 three-way comparison operator

core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/scanner/LexerTests.java

@@ -29,14 +29,18 @@ public class LexerTests extends BaseTestCase {
 	private static final LexerOptions DEFAULT_OPTIONS = new LexerOptions();
 	private static final LexerOptions NO_DOLLAR = new LexerOptions();
 	private static final LexerOptions NO_MINMAX = new LexerOptions();
+	private static final LexerOptions NO_MINMAX_CPP = new LexerOptions();
 	private static final LexerOptions SLASH_PERCENT = new LexerOptions();
 	private static final LexerOptions CPP_OPTIONS = new LexerOptions();
 	static {
 		NO_DOLLAR.fSupportDollarInIdentifiers = false;
 		NO_MINMAX.fSupportMinAndMax = false;
+		NO_MINMAX_CPP.fSupportMinAndMax = false;
+		NO_MINMAX_CPP.fSupportThreeWayComparisonOperator = true;
 		SLASH_PERCENT.fSupportSlashPercentComments = true;
 		CPP_OPTIONS.fSupportRawStringLiterals = true;
 		CPP_OPTIONS.fSupportDigitSeparators = true;
+		CPP_OPTIONS.fSupportThreeWayComparisonOperator = true;
 	}
 
 	static String TRIGRAPH_REPLACES_CHARS = "#^[]|{}~\\";
@@ -716,11 +720,26 @@ public class LexerTests extends BaseTestCase {
 				IToken.tGTEQUAL, IToken.tAND, IToken.tOR, IToken.tINCR, IToken.tDECR, IToken.tCOMMA, IToken.tARROWSTAR,
 				IToken.tARROW, IGCCToken.tMIN, IGCCToken.tMAX, Lexer.tOTHER_CHARACTER, };
 
+		verifyOperatorAndPunctuators(ops, tokens, DEFAULT_OPTIONS, NO_MINMAX);
+	}
+
+	public void testOperatorAndPunctuatorsCpp20() throws Exception {
+		final String ops = "<<>><<=>>===!=<=>>=<=&&";
+
+		final int[] tokens = new int[] { IToken.tSHIFTL, IToken.tSHIFTR, IToken.tSHIFTLASSIGN, IToken.tSHIFTRASSIGN,
+				IToken.tEQUAL, IToken.tNOTEQUAL, IToken.tTHREEWAYCOMPARISON, IToken.tGTEQUAL, IToken.tLTEQUAL,
+				IToken.tAND, };
+
+		verifyOperatorAndPunctuators(ops, tokens, CPP_OPTIONS, NO_MINMAX_CPP);
+	}
+
+	private void verifyOperatorAndPunctuators(String ops, int[] tokens, LexerOptions options,
+			LexerOptions optionsNoMinMax) throws Exception {
 		for (int splices = 0; splices < 9; splices++) {
 			for (int trigraphs = 0; trigraphs < 6; trigraphs++) {
 				StringBuilder buf = new StringBuilder();
 				String input = useTrigraphs(ops.toCharArray(), trigraphs);
-				init(instertLineSplices(input, splices));
+				init(instertLineSplices(input, splices), options);
 				for (int token2 : tokens) {
 					Token token = fLexer.currentToken();
 					buf.append(token.getCharImage());
@@ -729,7 +748,7 @@ public class LexerTests extends BaseTestCase {
 				eof();
 				assertEquals(ops, buf.toString()); // check token image
 
-				init(input, NO_MINMAX);
+				init(input, optionsNoMinMax);
 				for (int token : tokens) {
 					switch (token) {
 					case IGCCToken.tMIN:

core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/ASTStringUtil.java

@@ -1167,6 +1167,8 @@ public class ASTStringUtil {
 			return Keywords.cpEQUAL;
 		case IASTBinaryExpression.op_notequals:
 			return Keywords.cpNOTEQUAL;
+		case IASTBinaryExpression.op_threewaycomparison:
+			return Keywords.cpTHREEWAYCOMPARISON;
 		case IASTBinaryExpression.op_max:
 			return Keywords.cpMAX;
 		case IASTBinaryExpression.op_min:

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/ASTSignatureUtil.java

@@ -1311,6 +1311,9 @@ public class ASTSignatureUtil {
 		case IASTBinaryExpression.op_notequals:
 			opString = String.valueOf(Keywords.cpNOTEQUAL);
 			break;
+		case IASTBinaryExpression.op_threewaycomparison:
+			opString = String.valueOf(Keywords.cpTHREEWAYCOMPARISON);
+			break;
 		case IASTBinaryExpression.op_max:
 			opString = String.valueOf(Keywords.cpMAX);
 			break;

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/IASTBinaryExpression.java

@@ -226,6 +226,13 @@ public interface IASTBinaryExpression extends IASTExpression {
 	 */
 	public static final int op_ellipses = 34;
 
+	/**
+	 * For c++, only.
+	 * <code>op_threewaycompare</code> represents <code><=></code> three-way comparison operator.
+	 * @since 8.0
+	 */
+	public static final int op_threewaycomparison = 35;
+
 	/**
 	 * Get the first operand.
 	 *

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/parser/IToken.java

@@ -85,6 +85,8 @@ public interface IToken {
 	int tNOTEQUAL = 35;
 	int tNOT = 36;
 	int tEQUAL = 37;
+	/** @since 8.0 */
+	int tTHREEWAYCOMPARISON = 8001;
 	int tASSIGN = 38;
 	int tUNKNOWN_CHAR = 39;
 	int tSHIFTL = 40;

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/parser/Keywords.java

@@ -279,6 +279,7 @@ public class Keywords {
 	public static final char[] cpNOTEQUAL = "!=".toCharArray();
 	public static final char[] cpNOT = "!".toCharArray();
 	public static final char[] cpEQUAL = "==".toCharArray();
+	public static final char[] cpTHREEWAYCOMPARISON = "<=>".toCharArray();
 	public static final char[] cpASSIGN = "=".toCharArray();
 	public static final char[] cpSHIFTL = "<<".toCharArray();
 	public static final char[] cpLTEQUAL = "<=".toCharArray();

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/ASTAmbiguousBinaryVsCastExpression.java

@@ -224,19 +224,21 @@ public abstract class ASTAmbiguousBinaryVsCastExpression extends ASTAmbiguousNod
 		case IASTBinaryExpression.op_max:
 		case IASTBinaryExpression.op_min:
 			return 7;
+		case IASTBinaryExpression.op_threewaycomparison:
+			return 8;
 		case IASTBinaryExpression.op_shiftLeft:
 		case IASTBinaryExpression.op_shiftRight:
-			return 8;
+			return 9;
 		case IASTBinaryExpression.op_plus:
 		case IASTBinaryExpression.op_minus:
-			return 9;
+			return 10;
 		case IASTBinaryExpression.op_multiply:
 		case IASTBinaryExpression.op_divide:
 		case IASTBinaryExpression.op_modulo:
-			return 10;
+			return 11;
 		case IASTBinaryExpression.op_pmarrow:
 		case IASTBinaryExpression.op_pmdot:
-			return 11;
+			return 12;
 		}
 		assert false;
 		return 0;

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/AbstractGNUSourceCodeParser.java

@@ -1123,6 +1123,9 @@ public abstract class AbstractGNUSourceCodeParser implements ISourceCodeParser {
 		case IToken.tNOTEQUAL:
 			op = IASTBinaryExpression.op_notequals;
 			break;
+		case IToken.tTHREEWAYCOMPARISON:
+			op = IASTBinaryExpression.op_threewaycomparison;
+			break;
 		case IToken.tGT:
 			op = IASTBinaryExpression.op_greaterThan;
 			break;
@@ -2731,6 +2734,7 @@ public abstract class AbstractGNUSourceCodeParser implements ISourceCodeParser {
 			case IToken.tDOT:
 			case IToken.tDOTSTAR:
 			case IToken.tEQUAL:
+			case IToken.tTHREEWAYCOMPARISON:
 			case IToken.tGT:
 			case IToken.tGT_in_SHIFTR:
 			case IToken.tGTEQUAL:

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/ValueFactory.java

@@ -224,6 +224,9 @@ public class ValueFactory {
 		case IASTBinaryExpression.op_greaterEqual:
 			value = v1 >= v2 ? 1l : 0l;
 			break;
+		case IASTBinaryExpression.op_threewaycomparison:
+			// TODO: implement for <=>
+			break;
 		case IASTBinaryExpression.op_binaryAnd:
 			value = v1 & v2;
 			break;

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/VariableReadWriteFlags.java

@@ -439,6 +439,7 @@ public abstract class VariableReadWriteFlags {
 		case IASTBinaryExpression.op_notequals:
 		case IASTBinaryExpression.op_shiftLeft:
 		case IASTBinaryExpression.op_shiftRight:
+		case IASTBinaryExpression.op_threewaycomparison:
 			return Optional.of(READ);
 
 		case IASTBinaryExpression.op_minus:

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/c/CASTBinaryExpression.java

@@ -234,6 +234,10 @@ public class CASTBinaryExpression extends ASTNode implements IASTBinaryExpressio
 		case op_notequals:
 			return new CBasicType(Kind.eInt, 0, this);
 
+		case op_threewaycomparison:
+			// TODO: implement for <=>
+			break;
+
 		case IASTBinaryExpression.op_plus:
 			if (type1 instanceof IArrayType) {
 				return Conversions.arrayTypeToPointerType((ICArrayType) type1);

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/c/GNUCSourceParser.java

@@ -548,6 +548,7 @@ public class GNUCSourceParser extends AbstractGNUSourceCodeParser {
 				break;
 			case IToken.tEQUAL:
 			case IToken.tNOTEQUAL:
+			case IToken.tTHREEWAYCOMPARISON:
 				lastOperator = new BinaryOperator(lastOperator, lastExpression, lt1, 80, 81);
 				break;
 			case IToken.tGT:

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/GNUCPPSourceParser.java

@@ -1106,6 +1106,7 @@ public class GNUCPPSourceParser extends AbstractGNUSourceCodeParser {
 				break;
 			case IToken.tEQUAL:
 			case IToken.tNOTEQUAL:
+			case IToken.tTHREEWAYCOMPARISON:
 				lastOperator = new BinaryOperator(lastOperator, expr, lt1, 80, 81);
 				break;
 			case IToken.tGT:

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/OverloadableOperator.java

@@ -34,9 +34,9 @@ public enum OverloadableOperator {
 	GT(">"), LT("<"), NOT("!"), BITCOMPLEMENT("~"), BITOR("|"), AMPER("&"), XOR("^"), MOD("%"), DIV("/"), STAR("*"),
 	PLUS("+"), BRACKET("[]"), PAREN("()"), ARROW("->"), ARROWSTAR("->*"), COMMA(","), MINUS("-"), DECR("--"),
 	INCR("++"), OR("||"), AND("&&"), ASSIGN("="), GTEQUAL(">="), LTEQUAL("<="), NOTEQUAL("!="), EQUAL("=="),
-	SHIFTR(">>"), SHIFTL("<<"), SHIFTLASSIGN("<<="), SHIFTRASSIGN(">>="), BITORASSIGN("|="), AMPERASSIGN("&="),
+	SHIFTR(">>"), SHIFTL("<<"), SHIFTLASSIGN("<<="), SHIFTRASSIGN(">>="), THREEWAYCOMPARISON("<=>"), BITORASSIGN("|="),
-	XORASSIGN("^="), MODASSIGN("%="), DIVASSIGN("/="), STARASSIGN("*="), MINUSASSIGN("-="), PLUSASSIGN("+="),
+	AMPERASSIGN("&="), XORASSIGN("^="), MODASSIGN("%="), DIVASSIGN("/="), STARASSIGN("*="), MINUSASSIGN("-="),
-	NEW("new"), DELETE_ARRAY("delete[]"), DELETE("delete"), NEW_ARRAY("new[]"),
+	PLUSASSIGN("+="), NEW("new"), DELETE_ARRAY("delete[]"), DELETE("delete"), NEW_ARRAY("new[]"),
 
 	/**
 	 * Cannot be overloaded by the user, however overload resolution needs to be performed.
@@ -155,6 +155,8 @@ public enum OverloadableOperator {
 			return LT;
 		case IToken.tLTEQUAL:
 			return LTEQUAL;
+		case IToken.tTHREEWAYCOMPARISON:
+			return THREEWAYCOMPARISON;
 
 		// other
 		case IToken.tASSIGN:
@@ -247,6 +249,8 @@ public enum OverloadableOperator {
 			return LT;
 		case IASTBinaryExpression.op_lessEqual:
 			return LTEQUAL;
+		case IASTBinaryExpression.op_threewaycomparison:
+			return THREEWAYCOMPARISON;
 
 		// other
 		case IASTBinaryExpression.op_assign:

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/BuiltinOperators.java

@@ -167,6 +167,10 @@ class BuiltinOperators {
 			comparison(true);
 			break;
 
+		case THREEWAYCOMPARISON:
+			// TODO: implement for <=>
+			break;
+
 		case GT:
 		case GTEQUAL:
 		case LT:

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalBinary.java

@@ -45,6 +45,7 @@ import static org.eclipse.cdt.core.dom.ast.IASTBinaryExpression.op_shiftLeft;
 import static org.eclipse.cdt.core.dom.ast.IASTBinaryExpression.op_shiftLeftAssign;
 import static org.eclipse.cdt.core.dom.ast.IASTBinaryExpression.op_shiftRight;
 import static org.eclipse.cdt.core.dom.ast.IASTBinaryExpression.op_shiftRightAssign;
+import static org.eclipse.cdt.core.dom.ast.IASTBinaryExpression.op_threewaycomparison;
 import static org.eclipse.cdt.core.dom.ast.IASTExpression.ValueCategory.LVALUE;
 import static org.eclipse.cdt.core.dom.ast.IASTExpression.ValueCategory.PRVALUE;
 import static org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.ExpressionTypes.glvalueType;
@@ -388,6 +389,10 @@ public class EvalBinary extends CPPDependentEvaluation {
 		case op_notequals:
 			return CPPBasicType.BOOLEAN;
 
+		case op_threewaycomparison:
+			// TODO: implement for <=>
+			return ProblemType.UNKNOWN_FOR_EXPRESSION;
+
 		case op_plus:
 			if (type1 instanceof IPointerType) {
 				return ExpressionTypes.restoreTypedefs(type1, originalType1);

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/rewrite/astwriter/ExpressionWriter.java

@@ -91,6 +91,7 @@ public class ExpressionWriter extends NodeWriter {
 	private static final String ELLIPSES = " ... "; //$NON-NLS-1$
 	private static final String NOT_EQUALS_OP = " != "; //$NON-NLS-1$
 	private static final String EQUALS_OP = " == "; //$NON-NLS-1$
+	private static final String THREEWAYCOMPARISON_OP = " <=> "; //$NON-NLS-1$
 	private static final String BINARY_OR_ASSIGN = " |= "; //$NON-NLS-1$
 	private static final String BINARY_XOR_ASSIGN_OP = " ^= "; //$NON-NLS-1$
 	private static final String BINARY_AND_ASSIGN_OP = " &= "; //$NON-NLS-1$
@@ -226,6 +227,8 @@ public class ExpressionWriter extends NodeWriter {
 			return EQUALS_OP;
 		case IASTBinaryExpression.op_notequals:
 			return NOT_EQUALS_OP;
+		case IASTBinaryExpression.op_threewaycomparison:
+			return THREEWAYCOMPARISON_OP;
 		case ICPPASTBinaryExpression.op_pmdot:
 			return PMDOT_OP;
 		case ICPPASTBinaryExpression.op_pmarrow:

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/CPreprocessor.java

@@ -99,6 +99,7 @@ public class CPreprocessor implements ILexerLog, IScanner, IAdaptable {
 	private static final int ORIGIN_INACTIVE_CODE = OffsetLimitReachedException.ORIGIN_INACTIVE_CODE;
 
 	private static final char[] ONE = "1".toCharArray(); //$NON-NLS-1$
+	private static final char[] CPP_IMPL_THREE_WAY_COMPARISON = "__cpp_impl_three_way_comparison".toCharArray(); //$NON-NLS-1$
 
 	// Standard built-ins
 	private static final ObjectStyleMacro __CDT_PARSER__ = new ObjectStyleMacro("__CDT_PARSER__".toCharArray(), //$NON-NLS-1$
@@ -352,6 +353,10 @@ public class CPreprocessor implements ILexerLog, IScanner, IAdaptable {
 		fIncludeSearchPath = configureIncludeSearchPath(new File(contextPath).getParentFile(), info);
 		setupMacroDictionary(configuration, info, language);
 
+		if (fMacroDictionary.containsKey(CPP_IMPL_THREE_WAY_COMPARISON)) {
+			fLexOptions.fSupportThreeWayComparisonOperator = true;
+		}
+
 		ILocationCtx ctx = fLocationMap.pushTranslationUnit(fRootContent.getFileLocation(), fRootContent.getSource());
 		Lexer lexer = new Lexer(fRootContent.getSource(), fLexOptions, this, this);
 		fRootContext = fCurrentContext = new ScannerContext(ctx, null, lexer);

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/Lexer.java

@@ -63,6 +63,7 @@ final public class Lexer implements ITokenSequence {
 		public boolean fSupportRawStringLiterals = false;
 		public boolean fSupportUserDefinedLiterals = false;
 		public boolean fSupportDigitSeparators = false;
+		public boolean fSupportThreeWayComparisonOperator = false;
 		public IncludeExportPatterns fIncludeExportPatterns;
 
 		@Override
@@ -641,7 +642,13 @@ final public class Lexer implements ITokenSequence {
 
 				switch (d) {
 				case '=':
-					nextCharPhase3();
+					final int se = nextCharPhase3();
+					if (fOptions.fSupportThreeWayComparisonOperator) {
+						if (se == '>') {
+							nextCharPhase3();
+							return newToken(IToken.tTHREEWAYCOMPARISON, start);
+						}
+					}
 					return newToken(IToken.tLTEQUAL, start);
 				case '<':
 					final int e = nextCharPhase3();

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/TokenUtil.java

@@ -78,6 +78,7 @@ public class TokenUtil {
 		case IToken.tGTEQUAL:
 		case IToken.tLT:
 		case IToken.tLTEQUAL:
+		case IToken.tTHREEWAYCOMPARISON:
 
 			// other
 		case IToken.tASSIGN:
@@ -164,6 +165,8 @@ public class TokenUtil {
 			return Keywords.cpNOT;
 		case IToken.tEQUAL:
 			return Keywords.cpEQUAL;
+		case IToken.tTHREEWAYCOMPARISON:
+			return Keywords.cpTHREEWAYCOMPARISON;
 		case IToken.tASSIGN:
 			return Keywords.cpASSIGN;
 		case IToken.tSHIFTL:

core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/refactoring/includes/BindingClassifier.java

@@ -650,6 +650,11 @@ public class BindingClassifier {
 						}
 					}
 
+					if (binaryExpression.getOperator() == IASTBinaryExpression.op_threewaycomparison) {
+						// TODO: implement for three-way comparison operator x <=> y
+						return PROCESS_CONTINUE;
+					}
+
 					IType operand1Type = binaryExpression.getOperand1().getExpressionType();
 					IASTInitializerClause operand2 = binaryExpression.getInitOperand2();
 					IType operand2Type;