fix breaking out of an else of a loop and add test

Author: timfel

graalpython/com.oracle.graal.python.test/src/tests/test_for.py

@@ -86,3 +86,29 @@ def test_else_continue():
             continue
 
     assert ["continue", "break"] == sequence
+
+
+def test_else_break():
+    iters = 0
+    while iters < 4:
+        for i in range(iters):
+            if False:
+                break
+            iters += 1
+        else:
+            iters += 1
+            break
+    assert iters == 2, "if the for-loop doesn't break, the else should be executed and break out of the outer loop"
+
+
+def test_else_break():
+    iters = 0
+    while iters < 40:
+        while iters < 10:
+            if False:
+                break
+            iters += 1
+        else:
+            iters += 1
+            break
+    assert iters == 11, "if the while-loop doesn't break, the else should be executed and break out of the outer loop"

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/NodeFactory.java

@@ -209,7 +209,11 @@ public StatementNode createContinueTarget(StatementNode child) {
     }
 
     public StatementNode createBreakTarget(StatementNode forNode) {
-        return new BreakTargetNode(forNode);
+        return new BreakTargetNode(forNode, null);
+    }
+
+    public StatementNode createBreakTarget(StatementNode forNode, StatementNode orelse) {
+        return new BreakTargetNode(forNode, orelse);
     }
 
     public YieldNode createYield(ExpressionNode right, FrameSlot returnSlot) {

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/control/BreakTargetNode.java

@@ -36,9 +36,11 @@ public final class BreakTargetNode extends StatementNode {
     private final BranchProfile defaultExitProfile = BranchProfile.create();
 
     @Child private StatementNode statement;
+    @Child private StatementNode orelse;
 
-    public BreakTargetNode(StatementNode statement) {
+    public BreakTargetNode(StatementNode statement, StatementNode orelse) {
         this.statement = statement;
+        this.orelse = orelse;
     }
 
     public StatementNode getStatement() {
@@ -52,6 +54,10 @@ public void executeVoid(VirtualFrame frame) {
             defaultExitProfile.enter();
         } catch (BreakException ex) {
             breakProfile.enter();
+            return;
+        }
+        if (orelse != null) {
+            orelse.executeVoid(frame);
         }
     }
 }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/parser/PythonTreeTranslator.java

@@ -1255,15 +1255,17 @@ private PNode createWhileNode(PNode test, StatementNode body, StatementNode orel
         StatementNode whileNode = factory.createWhile(factory.toBooleanCastNode(test), wrappedBody);
         // assignSourceFromNode(node, whileNode);
 
-        if (!EmptyNode.isEmpty(orelse)) {
+        if (info.hasBreak()) {
+            if (!EmptyNode.isEmpty(orelse)) {
+                whileNode = factory.createBreakTarget(whileNode, orelse);
+            } else {
+                whileNode = factory.createBreakTarget(whileNode);
+            }
+        } else if (!EmptyNode.isEmpty(orelse)) {
             whileNode = factory.createElse(whileNode, orelse);
         }
 
-        if (info.hasBreak()) {
-            return factory.createBreakTarget(whileNode);
-        } else {
-            return whileNode;
-        }
+        return whileNode;
     }
 
     @Override
@@ -1288,15 +1290,17 @@ private StatementNode createForNode(StatementNode target, ExpressionNode iter, S
         StatementNode forNode = createForInScope(target, iter, wrappedBody);
         // assignSourceFromNode(node, forNode);
 
-        if (!EmptyNode.isEmpty(orelse)) {
+        if (info.hasBreak()) {
+            if (!EmptyNode.isEmpty(orelse)) {
+                forNode = factory.createBreakTarget(forNode, orelse);
+            } else {
+                forNode = factory.createBreakTarget(forNode);
+            }
+        } else if (!EmptyNode.isEmpty(orelse)) {
             forNode = factory.createElse(forNode, orelse);
         }
 
-        if (info.hasBreak()) {
-            return factory.createBreakTarget(forNode);
-        } else {
-            return forNode;
-        }
+        return forNode;
     }
 
     private LoopNode createForInScope(StatementNode target, ExpressionNode iterator, StatementNode body) {