Bug 534420 - Add initial support for [[nodiscard]] attribute

Change-Id: I3bb7e1b4068c5e95a8247be152b9e428f9207bdc

core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/pdom/tests/CPPFunctionTests.java

@@ -152,6 +152,12 @@ public class CPPFunctionTests extends PDOMTestBase {
 		assertTrue(((ICPPFunction) bindings[0]).isNoReturn());
 	}
 
+	private void assertNoDiscardFunction(String functionName) throws CoreException {
+		IBinding[] bindings = findQualifiedName(pdom, functionName);
+		assertEquals(1, bindings.length);
+		assertTrue(((ICPPFunction) bindings[0]).isNoDiscard());
+	}
+
 	public void testNoReturnCPPFunction() throws Exception {
 		assertNoReturnFunction("noReturnCPPFunction");
 		assertNoReturnFunction("trailingNoReturnStdAttributeDecl");
@@ -160,6 +166,14 @@ public class CPPFunctionTests extends PDOMTestBase {
 		assertNoReturnFunction("leadingNoReturnStdAttributeDef");
 	}
 
+	public void testNoDiscardCPPFunction() throws Exception {
+		assertNoDiscardFunction("noDiscardCPPFunction");
+		assertNoDiscardFunction("trailingNoDiscardStdAttributeDecl");
+		assertNoDiscardFunction("leadingNoDiscardStdAttributeDecl");
+		assertNoDiscardFunction("trailingNoDiscardStdAttributeDef");
+		assertNoDiscardFunction("leadingNoDiscardStdAttributeDef");
+	}
+
 	public void testForwardDeclarationType() throws Exception {
 		assertType(pdom, "forwardDeclaration", ICPPFunction.class);
 	}

core/org.eclipse.cdt.core.tests/resources/pdomtests/functionTests/modifiers.cpp

@@ -10,6 +10,12 @@ void leadingNoReturnStdAttributeDecl() [[noreturn]];
 [[noreturn]] void trailingNoReturnStdAttributeDef(){}
 void leadingNoReturnStdAttributeDef() [[noreturn]]{}
 
+int noDiscardCPPFunction() __attribute__((warn_unused_result));
+[[nodiscard]] int trailingNoDiscardStdAttributeDecl();
+int leadingNoDiscardStdAttributeDecl() [[nodiscard]];
+[[nodiscard]] int trailingNoDiscardStdAttributeDef(){return 0;}
+int leadingNoDiscardStdAttributeDef() [[nodiscard]]{return 0;}
+
 void voidCPPFunction();
 int intCPPFunction();
 double doubleCPPFunction();

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

@@ -65,4 +65,12 @@ public interface IFunction extends IBinding {
 	 * @since 5.4
 	 */
 	public boolean isNoReturn();
+
+	/**
+	 * Returns {@code true} if return value of this function must not be discarded.
+	 * Based on 'nodiscard' attribute in the function declaration or in C using
+	 * the flag 'warn_unused_result'
+	 * @since 6.12
+	 */
+	public boolean isNoDiscard();
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/parser/util/AttributeUtil.java

@@ -26,6 +26,8 @@ import org.eclipse.cdt.core.parser.StandardAttributes;
  */
 public class AttributeUtil {
 	private static final String[] ATTRIBUTE_NORETURN = new String[] { "__noreturn__", StandardAttributes.NORETURN }; //$NON-NLS-1$
+	private static final String[] ATTRIBUTE_NODISCARD = new String[] { "warn_unused_result", //$NON-NLS-1$
+			StandardAttributes.NODISCARD };
 
 	// Not instantiatable.
 	private AttributeUtil() {
@@ -54,6 +56,14 @@ public class AttributeUtil {
 		return hasAttribute(node, ATTRIBUTE_NORETURN);
 	}
 
+	/**
+	 * Returns {@code true} if the node has a "nodiscard" attribute.
+	 * @since 6.12
+	 */
+	public static boolean hasNodiscardAttribute(IASTAttributeOwner node) {
+		return hasAttribute(node, ATTRIBUTE_NODISCARD);
+	}
+
 	/**
 	 * Returns character representation of the attribute argument, or {@code null} if the attribute
 	 * has zero or more than one argument.

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

@@ -496,6 +496,12 @@ public class CFunction extends PlatformObject implements IFunction, ICInternalFu
 		return dtor != null && AttributeUtil.hasNoreturnAttribute(dtor);
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		IASTFunctionDeclarator dtor = getPreferredDtor();
+		return dtor != null && AttributeUtil.hasNodiscardAttribute(dtor);
+	}
+
 	protected IASTFunctionDeclarator getPreferredDtor() {
 		IASTFunctionDeclarator dtor = getDefinition();
 		if (dtor != null)

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

@@ -161,6 +161,11 @@ public class CPPClassSpecialization extends CPPSpecialization
 		public boolean isConstexpr() {
 			return false;
 		}
+
+		@Override
+		public boolean isNoDiscard() {
+			return false;
+		}
 	}
 
 	public final static class RecursionResolvingConstructor extends RecursionResolvingMethod

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

@@ -159,6 +159,11 @@ public class CPPDeferredFunction extends CPPUnknownBinding
 		return false;
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		return false;
+	}
+
 	@Override
 	public int getRequiredArgumentCount() {
 		return 0;

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

@@ -104,6 +104,11 @@ public class CPPFunction extends PlatformObject implements ICPPFunction, ICPPInt
 		public int getRequiredArgumentCount() {
 			return 0;
 		}
+
+		@Override
+		public boolean isNoDiscard() {
+			return false;
+		}
 	}
 
 	public static final ICPPFunction UNINITIALIZED_FUNCTION = new CPPFunction(null) {
@@ -739,6 +744,11 @@ public class CPPFunction extends PlatformObject implements ICPPFunction, ICPPInt
 		return isNoReturn(getPreferredDtor());
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		return isNoDiscard(getPreferredDtor());
+	}
+
 	public static boolean isNoReturn(ICPPASTFunctionDeclarator dtor) {
 		if (dtor == null) {
 			return false;
@@ -753,6 +763,20 @@ public class CPPFunction extends PlatformObject implements ICPPFunction, ICPPInt
 		return false;
 	}
 
+	public static boolean isNoDiscard(ICPPASTFunctionDeclarator dtor) {
+		if (dtor == null) {
+			return false;
+		}
+		if (AttributeUtil.hasNodiscardAttribute(dtor)) {
+			return true;
+		}
+		IASTNode parent = dtor.getParent();
+		if (parent instanceof IASTAttributeOwner) {
+			return AttributeUtil.hasNodiscardAttribute((IASTAttributeOwner) parent);
+		}
+		return false;
+	}
+
 	public static ICPPExecution getFunctionBodyExecution(ICPPFunction function) {
 		if (function instanceof ICPPComputableFunction) {
 			return ((ICPPComputableFunction) function).getFunctionBodyExecution();

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

@@ -341,4 +341,12 @@ public class CPPFunctionSpecialization extends CPPSpecialization
 		}
 		return CPPTemplates.instantiateFunctionBody(this);
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		ICPPFunction f = (ICPPFunction) getSpecializedBinding();
+		if (f != null)
+			return f.isNoDiscard();
+		return false;
+	}
 }

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

@@ -392,6 +392,11 @@ public class CPPFunctionTemplate extends CPPTemplateDefinition implements ICPPFu
 		return CPPFunction.isNoReturn(getFirstFunctionDtor());
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		return CPPFunction.isNoDiscard(getFirstFunctionDtor());
+	}
+
 	private IASTDeclarator getDeclaratorByName(IASTNode node) {
 		// Skip qualified names and nested declarators.
 		while (node != null) {

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

@@ -174,4 +174,9 @@ public class CPPUnknownMethod extends CPPUnknownMember implements ICPPMethod {
 	public boolean isConstexpr() {
 		return false;
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		return false;
+	}
 }

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

@@ -183,4 +183,9 @@ class AutoTypeResolver implements ICPPFunctionTemplate {
 	public boolean isNoReturn() {
 		throw new UnsupportedOperationException(UNEXPECTED_CALL);
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		throw new UnsupportedOperationException(UNEXPECTED_CALL);
+	}
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/index/composite/c/CompositeCFunction.java

@@ -83,4 +83,9 @@ class CompositeCFunction extends CompositeCBinding implements IFunction {
 	public boolean isNoReturn() {
 		return ((IFunction) rbinding).isNoReturn();
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		return ((IFunction) rbinding).isNoDiscard();
+	}
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/index/composite/cpp/CompositeCPPFunction.java

@@ -152,4 +152,9 @@ class CompositeCPPFunction extends CompositeCPPBinding implements ICPPFunction,
 	public ICPPExecution getFunctionBodyExecution() {
 		return CPPFunction.getFunctionBodyExecution((ICPPFunction) rbinding);
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		return ((ICPPFunction) rbinding).isNoDiscard();
+	}
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/PDOM.java

@@ -302,10 +302,13 @@ public class PDOM extends PlatformObject implements IPDOM {
 	 *
 	 *  CDT 9.9 development (version not supported on the 9.8.x branch)
 	 *  215.0 - Corruption due to wrong record size in field/variable template partial specialization, bug 549028.
+	 *
+	 *  CDT 9.12 development (version not supported on the 9.11.x branch)
+	 *  216.0 - Added nodiscard function information, bug 534420
 	 */
-	private static final int MIN_SUPPORTED_VERSION = version(215, 0);
+	private static final int MIN_SUPPORTED_VERSION = version(216, 0);
-	private static final int MAX_SUPPORTED_VERSION = version(215, Short.MAX_VALUE);
+	private static final int MAX_SUPPORTED_VERSION = version(216, Short.MAX_VALUE);
-	private static final int DEFAULT_VERSION = version(215, 0);
+	private static final int DEFAULT_VERSION = version(216, 0);
 
 	private static int version(int major, int minor) {
 		return (major << 16) + minor;

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/c/PDOMCAnnotations.java

@@ -32,6 +32,9 @@ class PDOMCAnnotations {
 	private static final int NO_RETURN_OFFSET = 4;
 	private static final int REGISTER_OFFSET = 5;
 	private static final int AUTO_OFFSET = 6;
+	private static final int NO_DISCARD_OFFSET = 7;
+	//NOTE: we are writing these annotations on a "byte" so if we need
+	//to add another value we need to use at least a short.
 
 	/**
 	 * Encodes annotations applicable to functions.
@@ -55,6 +58,8 @@ class PDOMCAnnotations {
 			annotation |= 1 << REGISTER_OFFSET;
 		if (function.isAuto())
 			annotation |= 1 << AUTO_OFFSET;
+		if (function.isNoDiscard())
+			annotation |= 1 << NO_DISCARD_OFFSET;
 
 		return annotation;
 	}
@@ -114,6 +119,13 @@ class PDOMCAnnotations {
 		return (annotation & (1 << NO_RETURN_OFFSET)) != 0;
 	}
 
+	/**
+	 * Checks if the "no discard" annotation is set.
+	 */
+	public static boolean isNoDiscardFunction(short annotation) {
+		return (annotation & (1 << NO_DISCARD_OFFSET)) != 0;
+	}
+
 	/**
 	 * Checks if the "register" annotation is set.
 	 */

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/c/PDOMCFunction.java

@@ -208,4 +208,9 @@ class PDOMCFunction extends PDOMBinding implements IFunction {
 	public IScope getFunctionScope() {
 		return null;
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		return PDOMCAnnotations.isNoDiscardFunction(getAnnotations());
+	}
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/cpp/PDOMCPPAnnotations.java

@@ -45,6 +45,7 @@ class PDOMCPPAnnotations {
 	private static final int PARAMETER_PACK_OFFSET = 7;
 	private static final int DELETED_OFFSET = 8;
 	private static final int NO_RETURN_OFFSET = 9;
+	private static final int NO_DISCARD_OFFSET = 10;
 
 	// Method annotations that don't fit on the first 16 bits of annotations.
 	private static final int VIRTUAL_OFFSET = 0;
@@ -82,6 +83,8 @@ class PDOMCPPAnnotations {
 			annotation |= 1 << PARAMETER_PACK_OFFSET;
 		if (function.isDeleted())
 			annotation |= 1 << DELETED_OFFSET;
+		if (function.isNoDiscard())
+			annotation |= 1 << NO_DISCARD_OFFSET;
 
 		return annotation;
 	}
@@ -226,6 +229,13 @@ class PDOMCPPAnnotations {
 		return (annotation & (1 << NO_RETURN_OFFSET)) != 0;
 	}
 
+	/**
+	 * Checks if the "no discard" annotation is set.
+	 */
+	public static boolean isNoDiscardFunction(short annotation) {
+		return (annotation & (1 << NO_DISCARD_OFFSET)) != 0;
+	}
+
 	/**
 	 * Checks if the "virtual" annotation is set.
 	 */

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/cpp/PDOMCPPFunction.java

@@ -449,4 +449,9 @@ class PDOMCPPFunction extends PDOMCPPBinding implements ICPPFunction, IPDOMOverl
 			return null;
 		}
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		return PDOMCPPAnnotations.isNoDiscardFunction(getAnnotations());
+	}
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/cpp/PDOMCPPFunctionSpecialization.java

@@ -342,4 +342,9 @@ class PDOMCPPFunctionSpecialization extends PDOMCPPSpecialization
 			return null;
 		}
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		return PDOMCPPAnnotations.isNoDiscardFunction(getAnnotations());
+	}
 }

lrparser/org.eclipse.cdt.core.lrparser/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %Bundle-Name.1
 Bundle-SymbolicName: org.eclipse.cdt.core.lrparser;singleton:=true
-Bundle-Version: 5.2.300.qualifier
+Bundle-Version: 5.2.400.qualifier
 Bundle-ClassPath: .
 Require-Bundle: org.eclipse.cdt.core,
  net.sourceforge.lpg.lpgjavaruntime;bundle-version="1.1.0";visibility:=reexport,

lrparser/org.eclipse.cdt.core.lrparser/old/org/eclipse/cdt/internal/core/dom/lrparser/c99/bindings/C99Function.java

@@ -39,6 +39,7 @@ public class C99Function extends PlatformObject implements IC99Binding, IFunctio
 	private boolean isStatic;
 	private boolean isVarArgs;
 	private boolean isNoReturn;
+	private boolean isNoDiscard;
 
 	// the scope that the function is in (must be the global scope, no?)
 	private IScope scope;
@@ -181,4 +182,13 @@ public class C99Function extends PlatformObject implements IC99Binding, IFunctio
 	public IBinding getOwner() {
 		return null;
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		return isNoDiscard;
+	}
+
+	public void setNoDiscard(boolean isNoDiscard) {
+		this.isNoDiscard = isNoDiscard;
+	}
 }