From 7db6752e202a393b6380df26f6254c1807495b59 Mon Sep 17 00:00:00 2001
From: svtk <svtk@unit-188.labs.intellij.net>
Date: Fri, 28 Oct 2011 13:33:38 +0400
Subject: [PATCH] Control flow graph traversing refactoring

---
 .../cfg/JetControlFlowGraphTraverser.java     | 116 ++++++++++++++++++
 .../jetbrains/jet/cfg/JetControlFlowTest.java |   1 -
 2 files changed, 116 insertions(+), 1 deletion(-)
 create mode 100644 compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowGraphTraverser.java

diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowGraphTraverser.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowGraphTraverser.java
new file mode 100644
index 00000000000..4ac299453dd
--- /dev/null
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowGraphTraverser.java
@@ -0,0 +1,116 @@
+package org.jetbrains.jet.lang.cfg;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+import org.jetbrains.jet.lang.cfg.pseudocode.Instruction;
+import org.jetbrains.jet.lang.cfg.pseudocode.LocalDeclarationInstruction;
+import org.jetbrains.jet.lang.cfg.pseudocode.Pseudocode;
+import org.jetbrains.jet.lang.cfg.pseudocode.SubroutineEnterInstruction;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * @author svtk
+ */
+public class JetControlFlowGraphTraverser {
+    public static <D> Map<Instruction, D> traverseInstructionGraphUntilFactsStabilization(
+            Pseudocode pseudocode,
+            InstructionsMergeStrategy<D> instructionsMergeStrategy,
+            D initialDataValue,
+            D initialDataValueForEnterInstruction,
+            boolean straightDirection) {
+        Map<Instruction, D> dataMap = Maps.newHashMap();
+        initializeDataMap(dataMap, pseudocode, initialDataValue);
+        dataMap.put(pseudocode.getEnterInstruction(), initialDataValueForEnterInstruction);
+
+        boolean[] changed = new boolean[1];
+        changed[0] = true;
+        while (changed[0]) {
+            changed[0] = false;
+            traverseSubGraph(pseudocode, instructionsMergeStrategy, Collections.<Instruction>emptyList(), straightDirection, dataMap, changed, false);
+        }
+        return dataMap;
+    }
+
+    private static <D> void initializeDataMap(
+            Map<Instruction, D> dataMap,
+            Pseudocode pseudocode,
+            D initialDataValue) {
+        List<Instruction> instructions = pseudocode.getInstructions();
+        for (Instruction instruction : instructions) {
+            dataMap.put(instruction, initialDataValue);
+            if (instruction instanceof LocalDeclarationInstruction) {
+                initializeDataMap(dataMap, ((LocalDeclarationInstruction) instruction).getBody(), initialDataValue);
+            }
+        }
+    }
+
+    private static <D> void traverseSubGraph(
+            Pseudocode pseudocode,
+            InstructionsMergeStrategy<D> instructionsMergeStrategy,
+            Collection<Instruction> previousSubGraphInstructions,
+            boolean straightDirection,
+            Map<Instruction, D> dataMap,
+            boolean[] changed,
+            boolean isLocal) {
+        List<Instruction> instructions = pseudocode.getInstructions();
+        SubroutineEnterInstruction enterInstruction = pseudocode.getEnterInstruction();
+        for (Instruction instruction : instructions) {
+            if (!isLocal && instruction instanceof SubroutineEnterInstruction) continue;
+
+            Collection<Instruction> allPreviousInstructions;
+            Collection<Instruction> previousInstructions = straightDirection
+                                                           ? instruction.getPreviousInstructions()
+                                                           : instruction.getNextInstructions();
+
+            if (instruction == enterInstruction && !previousSubGraphInstructions.isEmpty()) {
+                allPreviousInstructions = Lists.newArrayList(previousInstructions);
+                allPreviousInstructions.addAll(previousSubGraphInstructions);
+            }
+            else {
+                allPreviousInstructions = previousInstructions;
+            }
+
+            if (instruction instanceof LocalDeclarationInstruction) {
+                Pseudocode subroutinePseudocode = ((LocalDeclarationInstruction) instruction).getBody();
+                traverseSubGraph(subroutinePseudocode, instructionsMergeStrategy, previousInstructions, straightDirection, dataMap, changed, true);
+            }
+            D previousDataValue = dataMap.get(instruction);
+
+            Collection<D> incomingEdgesData = Sets.newHashSet();
+
+            for (Instruction previousInstruction : allPreviousInstructions) {
+                incomingEdgesData.add(dataMap.get(previousInstruction));
+            }
+            D mergedData = instructionsMergeStrategy.execute(instruction, incomingEdgesData);
+            if (!mergedData.equals(previousDataValue)) {
+                changed[0] = true;
+                dataMap.put(instruction, mergedData);
+            }
+        }
+    }
+
+    public static void traverseAndAnalyzeInstructionGraph(
+            Pseudocode pseudocode,
+            InstructionDataAnalyzeStrategy instructionDataAnalyzeStrategy) {
+        List<Instruction> instructions = pseudocode.getInstructions();
+        for (Instruction instruction : instructions) {
+            if (instruction instanceof LocalDeclarationInstruction) {
+                traverseAndAnalyzeInstructionGraph(((LocalDeclarationInstruction) instruction).getBody(), instructionDataAnalyzeStrategy);
+            }
+            instructionDataAnalyzeStrategy.execute(instruction);
+        }
+    }
+    
+    interface InstructionsMergeStrategy<D> {
+        D execute(Instruction instruction, Collection<D> incomingEdgesData);
+    }
+
+    interface InstructionDataAnalyzeStrategy {
+        void execute(Instruction instruction);
+    }
+}
diff --git a/compiler/tests/org/jetbrains/jet/cfg/JetControlFlowTest.java b/compiler/tests/org/jetbrains/jet/cfg/JetControlFlowTest.java
index b9efa562bcf..b56e4930a24 100644
--- a/compiler/tests/org/jetbrains/jet/cfg/JetControlFlowTest.java
+++ b/compiler/tests/org/jetbrains/jet/cfg/JetControlFlowTest.java
@@ -270,7 +270,6 @@ public class JetControlFlowTest extends JetTestCaseBase {
                 @Override
                 public void visitNondeterministicJump(NondeterministicJumpInstruction instruction) {
                     //todo print edges
-                    visitInstruction(instruction);
                     printEdge(out, nodeToName.get(instruction), nodeToName.get(instruction.getNext()), null);
                 }