vvysotskyi commented on a change in pull request #1686: DRILL-6524: Prevent
incorrect scalar replacement for the case of assigning references inside if
block
URL: https://github.com/apache/drill/pull/1686#discussion_r264792590
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/compile/bytecode/MethodAnalyzer.java
##########
@@ -36,70 +46,147 @@
* as factories that will provide our own derivative of Frame<> which we use
to detect
*/
public class MethodAnalyzer<V extends Value> extends Analyzer <V> {
+
+ // list of method instructions which is analyzed
+ private InsnList insnList;
+
+ /**
+ * Constructor.
+ *
+ * @param interpreter the interpreter to use
+ */
+ public MethodAnalyzer(Interpreter<V> interpreter) {
+ super(interpreter);
+ }
+
+ @Override
+ protected Frame<V> newFrame(int maxLocals, int maxStack) {
+ return new AssignmentTrackingFrame<>(maxLocals, maxStack);
+ }
+
+ @Override
+ protected Frame<V> newFrame(Frame<? extends V> src) {
+ return new AssignmentTrackingFrame<>(src);
+ }
+
+ @Override
+ protected void newControlFlowEdge(int insnIndex, int successorIndex) {
+ AssignmentTrackingFrame<V> oldFrame = (AssignmentTrackingFrame<V>)
getFrames()[insnIndex];
+ AbstractInsnNode insn = insnList.get(insnIndex);
+ if (insn.getType() == AbstractInsnNode.LABEL) {
+ // checks whether current label corresponds to the end of conditional
block to restore previous
+ // local variables set
+ if (insn.equals(oldFrame.labelsStack.peekFirst())) {
+ oldFrame.localVariablesSet.pop();
+ oldFrame.labelsStack.pop();
+ }
+ }
+ }
+
+ @Override
+ public Frame<V>[] analyze(String owner, MethodNode method) throws
AnalyzerException {
+ insnList = method.instructions;
+ return super.analyze(owner, method);
+ }
+
/**
* Custom Frame<> that captures setLocal() calls in order to associate values
- * that are assigned to the same local variable slot.
+ * that are assigned to the same local variable slot. Also it controls stack
to determine whether
+ * object was assigned to the value declared outside of conditional block.
*
* <p>Since this is almost a pass-through, the constructors' arguments match
* those from Frame<>.
*/
private static class AssignmentTrackingFrame<V extends Value> extends
Frame<V> {
+
+ // represents stacks of variable sets declared inside current code block
Review comment:
Thanks, done.
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