Use a control flow exception to communicate iterator exhaustion

Author: msimacek

Diff for: graalpython/com.oracle.graal.python.test/src/com/oracle/graal/python/test/datatype/PRangeTests.java

@@ -33,6 +33,7 @@
 import com.oracle.graal.python.PythonLanguage;
 import com.oracle.graal.python.builtins.objects.range.PIntRange;
 import com.oracle.graal.python.builtins.objects.range.PRange;
+import com.oracle.graal.python.lib.IteratorExhausted;
 import com.oracle.graal.python.lib.PyIterNextNode;
 import com.oracle.graal.python.lib.PyObjectGetIter;
 import com.oracle.graal.python.nodes.PGuards;
@@ -69,13 +70,14 @@ public void loopWithOnlyStop() throws UnexpectedResultException {
             Object iter = PyObjectGetIter.executeUncached(range);
 
             while (true) {
-                Object next = PyIterNextNode.executeUncached(iter);
-                if (PyIterNextNode.isExhausted(next)) {
+                try {
+                    Object next = PyIterNextNode.executeUncached(iter);
+                    int item = PGuards.expectInteger(next);
+                    assertEquals(index, item);
+                    index++;
+                } catch (IteratorExhausted e) {
                     break;
                 }
-                int item = PGuards.expectInteger(next);
-                assertEquals(index, item);
-                index++;
             }
         } finally {
             PythonTests.closeContext();
@@ -92,13 +94,14 @@ public void loopWithStep() throws UnexpectedResultException {
             Object iter = PyObjectGetIter.executeUncached(range);
 
             while (true) {
-                Object next = PyIterNextNode.executeUncached(iter);
-                if (PyIterNextNode.isExhausted(next)) {
+                try {
+                    Object next = PyIterNextNode.executeUncached(iter);
+                    int item = PGuards.expectInteger(next);
+                    assertEquals(index, item);
+                    index += 2;
+                } catch (IteratorExhausted e) {
                     break;
                 }
-                int item = PGuards.expectInteger(next);
-                assertEquals(index, item);
-                index += 2;
             }
         } finally {
             PythonTests.closeContext();

Diff for: graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/ArrayModuleBuiltins.java

@@ -61,6 +61,7 @@
 import com.oracle.graal.python.builtins.objects.range.PIntRange;
 import com.oracle.graal.python.builtins.objects.str.StringNodes.CastToTruffleStringCheckedNode;
 import com.oracle.graal.python.builtins.objects.type.TypeNodes;
+import com.oracle.graal.python.lib.IteratorExhausted;
 import com.oracle.graal.python.lib.PyIterNextNode;
 import com.oracle.graal.python.lib.PyObjectCallMethodObjArgs;
 import com.oracle.graal.python.lib.PyObjectGetIter;
@@ -295,18 +296,19 @@ static PArray arrayIteratorInitializer(VirtualFrame frame, Node inliningTarget,
 
                 int length = 0;
                 while (true) {
-                    Object nextValue = nextNode.execute(frame, inliningTarget, iter);
-                    if (PyIterNextNode.isExhausted(nextValue)) {
-                        break;
-                    }
                     try {
-                        length = PythonUtils.addExact(length, 1);
-                        ensureCapacityNode.execute(inliningTarget, array, length);
-                    } catch (OverflowException e) {
-                        CompilerDirectives.transferToInterpreterAndInvalidate();
-                        throw PRaiseNode.raiseStatic(inliningTarget, MemoryError);
+                        Object nextValue = nextNode.execute(frame, inliningTarget, iter);
+                        try {
+                            length = PythonUtils.addExact(length, 1);
+                            ensureCapacityNode.execute(inliningTarget, array, length);
+                        } catch (OverflowException e) {
+                            CompilerDirectives.transferToInterpreterAndInvalidate();
+                            throw PRaiseNode.raiseStatic(inliningTarget, MemoryError);
+                        }
+                        putValueNode.execute(frame, inliningTarget, array, length - 1, nextValue);
+                    } catch (IteratorExhausted e) {
+                        break;
                     }
-                    putValueNode.execute(frame, inliningTarget, array, length - 1, nextValue);
                 }
 
                 setLengthNode.execute(inliningTarget, array, length);