From bb2e1c04ec9236db24aaace0f430be7e5b24905d Mon Sep 17 00:00:00 2001
From: Svetlana Isakova <svetlana.isakova@jetbrains.com>
Date: Fri, 7 Dec 2012 20:09:27 +0400
Subject: [PATCH] updated allow dead instructions handling

Added labels collecting:
Allow dead instruction block can have several starters and
one stopper that knows all corresponding starters by labels
---
 .../jet/lang/cfg/JetControlFlowBuilder.java   |  9 +-
 .../cfg/JetControlFlowBuilderAdapter.java     | 17 +++-
 .../jet/lang/cfg/JetControlFlowProcessor.java | 15 ++--
 .../src/org/jetbrains/jet/lang/cfg/Label.java |  1 +
 .../JetControlFlowInstructionsGenerator.java  | 23 +++--
 .../lang/cfg/pseudocode/PseudocodeImpl.java   | 87 ++++++++++++-------
 6 files changed, 104 insertions(+), 48 deletions(-)

diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilder.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilder.java
index 04df878fdb3..2cf2df1f776 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilder.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilder.java
@@ -21,6 +21,7 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.cfg.pseudocode.Pseudocode;
 import org.jetbrains.jet.lang.psi.*;
 
+import java.util.Collection;
 import java.util.List;
 
 /**
@@ -37,8 +38,12 @@ public interface JetControlFlowBuilder {
     Label createUnboundLabel(@NotNull String name);
 
     void bindLabel(@NotNull Label label);
-    void allowDead();
-    void stopAllowDead();
+
+    @NotNull
+    Label createAllowDeadLabel(@NotNull Collection<Label> allowDeadLabels);
+    @NotNull
+    Label createAllowDeadLabel(@NotNull String name, @NotNull Collection<Label> allowDeadLabels);
+    void stopAllowDead(@NotNull Collection<Label> allowDeadLabels);
 
     // Jumps
     void jump(@NotNull Label label);
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilderAdapter.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilderAdapter.java
index 05f837a3566..3e58dc15762 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilderAdapter.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilderAdapter.java
@@ -21,6 +21,7 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.cfg.pseudocode.Pseudocode;
 import org.jetbrains.jet.lang.psi.*;
 
+import java.util.Collection;
 import java.util.List;
 
 /**
@@ -61,16 +62,24 @@ public class JetControlFlowBuilderAdapter implements JetControlFlowBuilder {
         builder.bindLabel(label);
     }
 
+    @NotNull
     @Override
-    public void allowDead() {
+    public Label createAllowDeadLabel(@NotNull Collection<Label> allowDeadLabels) {
         assert builder != null;
-        builder.allowDead();
+        return builder.createAllowDeadLabel(allowDeadLabels);
+    }
+
+    @NotNull
+    @Override
+    public Label createAllowDeadLabel(@NotNull String name, @NotNull Collection<Label> allowDeadLabels) {
+        assert builder != null;
+        return builder.createAllowDeadLabel(name, allowDeadLabels);
     }
 
     @Override
-    public void stopAllowDead() {
+    public void stopAllowDead(@NotNull Collection<Label> allowDeadLabels) {
         assert builder != null;
-        builder.stopAllowDead();
+        builder.stopAllowDead(allowDeadLabels);
     }
 
     @Override
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java
index 8ece537a383..ad61ae1fe3e 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java
@@ -37,6 +37,7 @@ import org.jetbrains.jet.lang.types.expressions.OperatorConventions;
 import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns;
 import org.jetbrains.jet.lexer.JetTokens;
 
+import java.util.Collection;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
@@ -378,8 +379,9 @@ public class JetControlFlowProcessor {
             }
             value(expression.getTryBlock(), inCondition);
 
+            Collection<Label> allowDeadLabels = Lists.newArrayList();
             if (hasCatches) {
-                builder.allowDead();
+                builder.createAllowDeadLabel(allowDeadLabels);
                 Label afterCatches = builder.createUnboundLabel("afterCatches");
                 builder.jump(afterCatches);
 
@@ -407,14 +409,14 @@ public class JetControlFlowProcessor {
                     if (catchBody != null) {
                         value(catchBody, false);
                     }
-                    builder.allowDead();
+                    builder.createAllowDeadLabel(allowDeadLabels);
                     builder.jump(afterCatches);
                 }
 
                 builder.bindLabel(afterCatches);
             }
             else {
-                builder.allowDead();
+                builder.createAllowDeadLabel(allowDeadLabels);
             }
 
             if (finallyBlock != null) {
@@ -429,7 +431,7 @@ public class JetControlFlowProcessor {
 
                 value(finallyBlock.getFinalExpression(), inCondition);
             }
-            builder.stopAllowDead();
+            builder.stopAllowDead(allowDeadLabels);
         }
 
         @Override
@@ -784,6 +786,7 @@ public class JetControlFlowProcessor {
             Label doneLabel = builder.createUnboundLabel();
 
             Label nextLabel = null;
+            Collection<Label> allowDeadLabels = Lists.newArrayList();
             for (Iterator<JetWhenEntry> iterator = expression.getEntries().iterator(); iterator.hasNext(); ) {
                 JetWhenEntry whenEntry = iterator.next();
 
@@ -818,7 +821,7 @@ public class JetControlFlowProcessor {
 
                 builder.bindLabel(bodyLabel);
                 value(whenEntry.getExpression(), inCondition);
-                builder.allowDead();
+                builder.createAllowDeadLabel(allowDeadLabels);
                 builder.jump(doneLabel);
 
                 if (!isIrrefutable) {
@@ -830,7 +833,7 @@ public class JetControlFlowProcessor {
             if (!hasElseOrIrrefutableBranch && !isWhenExhaust) {
                 trace.report(NO_ELSE_IN_WHEN.on(expression));
             }
-            builder.stopAllowDead();
+            builder.stopAllowDead(allowDeadLabels);
         }
 
         @Override
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/Label.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/Label.java
index 120a473e455..5f4a49455c6 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/Label.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/Label.java
@@ -21,4 +21,5 @@ package org.jetbrains.jet.lang.cfg;
  */
 public interface Label {
     String getName();
+    boolean allowDead();
 }
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/JetControlFlowInstructionsGenerator.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/JetControlFlowInstructionsGenerator.java
index 1500e122778..11821754e77 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/JetControlFlowInstructionsGenerator.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/JetControlFlowInstructionsGenerator.java
@@ -30,6 +30,7 @@ public class JetControlFlowInstructionsGenerator extends JetControlFlowBuilderAd
     private final Stack<BreakableBlockInfo> loopInfo = new Stack<BreakableBlockInfo>();
     private final Map<JetElement, BreakableBlockInfo> elementToBlockInfo = new HashMap<JetElement, BreakableBlockInfo>();
     private int labelCount = 0;
+    private int allowDeadLabelCount = 0;
 
     private final Stack<JetControlFlowInstructionsGeneratorWorker> builders = new Stack<JetControlFlowInstructionsGeneratorWorker>();
 
@@ -272,18 +273,26 @@ public class JetControlFlowInstructionsGenerator extends JetControlFlowBuilderAd
             pseudocode.bindLabel(label);
         }
 
+        @NotNull
         @Override
-        public void allowDead() {
-            Label allowedDeadLabel = createUnboundLabel();
-            bindLabel(allowedDeadLabel);
-            pseudocode.allowDead(allowedDeadLabel);
+        public Label createAllowDeadLabel(@NotNull Collection<Label> allowDeadLabels) {
+            return createAllowDeadLabel("d" + allowDeadLabelCount++, allowDeadLabels);
+        }
+
+        @NotNull
+        @Override
+        public Label createAllowDeadLabel(@NotNull String name, @NotNull Collection<Label> allowDeadLabels) {
+            Label label = pseudocode.createAllowDeadLabel(name);
+            bindLabel(label);
+            allowDeadLabels.add(label);
+            return label;
         }
 
         @Override
-        public void stopAllowDead() {
-            Label allowedDeadLabel = createUnboundLabel();
+        public void stopAllowDead(@NotNull Collection<Label> allowDeadLabels) {
+            Label allowedDeadLabel = createUnboundLabel("stop " + allowDeadLabels);
             bindLabel(allowedDeadLabel);
-            pseudocode.stopAllowDead(allowedDeadLabel);
+            pseudocode.stopAllowDead(allowedDeadLabel, allowDeadLabels);
         }
 
         @Override
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/PseudocodeImpl.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/PseudocodeImpl.java
index a9563d36dfd..c23e8eb6f20 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/PseudocodeImpl.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/PseudocodeImpl.java
@@ -36,11 +36,13 @@ public class PseudocodeImpl implements Pseudocode {
 
     public class PseudocodeLabel implements Label {
         private final String name;
+        private final boolean allowDead;
         private Integer targetInstructionIndex;
 
 
-        private PseudocodeLabel(String name) {
+        private PseudocodeLabel(String name, boolean allowDead) {
             this.name = name;
+            this.allowDead = allowDead;
         }
 
         @Override
@@ -48,6 +50,11 @@ public class PseudocodeImpl implements Pseudocode {
             return name;
         }
 
+        @Override
+        public boolean allowDead() {
+            return allowDead;
+        }
+
         @Override
         public String toString() {
             return name;
@@ -85,8 +92,7 @@ public class PseudocodeImpl implements Pseudocode {
     private final Map<JetExpression, LoopInfo> loopInfo = Maps.newHashMap();
     
     private final List<PseudocodeLabel> labels = new ArrayList<PseudocodeLabel>();
-    private final List<PseudocodeLabel> allowedDeadLabels = new ArrayList<PseudocodeLabel>();
-    private final List<PseudocodeLabel> stopAllowDeadLabels = new ArrayList<PseudocodeLabel>();
+    private final Map<PseudocodeLabel, Collection<Label>> stopAllowDeadLabels = Maps.newHashMap();
 
     private final JetElement correspondingElement;
     private SubroutineExitInstruction exitInstruction;
@@ -126,17 +132,21 @@ public class PseudocodeImpl implements Pseudocode {
     }
 
     /*package*/ PseudocodeLabel createLabel(String name) {
-        PseudocodeLabel label = new PseudocodeLabel(name);
+        return createLabel(name, false);
+    }
+
+    private PseudocodeLabel createLabel(String name, boolean allowDead) {
+        PseudocodeLabel label = new PseudocodeLabel(name, allowDead);
         labels.add(label);
         return label;
     }
     
-    /*package*/ void allowDead(Label label) {
-        allowedDeadLabels.add((PseudocodeLabel) label);
+    /*package*/ Label createAllowDeadLabel(String name) {
+        return createLabel(name, true);
     }
     
-    /*package*/ void stopAllowDead(Label label) {
-        stopAllowDeadLabels.add((PseudocodeLabel) label);
+    /*package*/ void stopAllowDead(Label label, Collection<Label> allowDeadLabels) {
+        stopAllowDeadLabels.put((PseudocodeLabel) label, allowDeadLabels);
     }
 
     @Override
@@ -373,24 +383,26 @@ public class PseudocodeImpl implements Pseudocode {
     }
 
     @NotNull
-    private Set<Instruction> prepareAllowedDeadInstructions() {
-        Set<Instruction> allowedDeadStartInstructions = Sets.newHashSet();
-        for (PseudocodeLabel allowedDeadLabel : allowedDeadLabels) {
-            Instruction allowedDeadInstruction = getJumpTarget(allowedDeadLabel);
-            if (((InstructionImpl)allowedDeadInstruction).isDead()) {
-                allowedDeadStartInstructions.add(allowedDeadInstruction);
+    private Map<Instruction, Label> prepareAllowDeadStarters() {
+        Map<Instruction, Label> allowedDeadBeginners = Maps.newHashMap();
+        for (PseudocodeLabel label : labels) {
+            if (!label.allowDead()) continue;
+            Instruction allowDeadPossibleBeginner = getJumpTarget(label);
+            if (((InstructionImpl)allowDeadPossibleBeginner).isDead()) {
+                allowedDeadBeginners.put(allowDeadPossibleBeginner, label);
             }
         }
-        return allowedDeadStartInstructions;
+        return allowedDeadBeginners;
     }
     
     @NotNull
-    private Set<Instruction> prepareStopAllowedDeadInstructions() {
-        Set<Instruction> stopAllowedDeadInstructions = Sets.newHashSet();
-        for (PseudocodeLabel stopAllowedDeadLabel : stopAllowDeadLabels) {
+    private Map<Instruction, Collection<Label>> prepareAllowDeadStoppers() {
+        Map<Instruction, Collection<Label>> stopAllowedDeadInstructions = Maps.newHashMap();
+        for (Map.Entry<PseudocodeLabel, Collection<Label>> entry : stopAllowDeadLabels.entrySet()) {
+            PseudocodeLabel stopAllowedDeadLabel = entry.getKey();
             Instruction stopAllowDeadInsruction = getJumpTarget(stopAllowedDeadLabel);
             if (((InstructionImpl)stopAllowDeadInsruction).isDead()) {
-                stopAllowedDeadInstructions.add(stopAllowDeadInsruction);
+                stopAllowedDeadInstructions.put(stopAllowDeadInsruction, entry.getValue());
             }
         }
         return stopAllowedDeadInstructions;
@@ -398,22 +410,39 @@ public class PseudocodeImpl implements Pseudocode {
 
     @NotNull
     private Collection<Instruction> collectAllowedDeadInstructions() {
-        Set<Instruction> allowedDeadStartInstructions = prepareAllowedDeadInstructions();
-        Set<Instruction> stopAllowDeadInstructions = prepareStopAllowedDeadInstructions();
+        // Allow dead instruction block can have several starters and
+        // one stopper that knows all corresponding starters by labels
+        Map<Instruction, Label> allowDeadStarters = prepareAllowDeadStarters();
+        Map<Instruction, Collection<Label>> allowDeadStoppers = prepareAllowDeadStoppers();
         Set<Instruction> allowedDeadInstructions = Sets.newHashSet();
 
-        for (Instruction allowedDeadStartInstruction : allowedDeadStartInstructions) {
-            collectAllowedDeadInstructions(allowedDeadStartInstruction, allowedDeadInstructions, stopAllowDeadInstructions);
+        for (Map.Entry<Instruction, Label> entry : allowDeadStarters.entrySet()) {
+            Instruction starter = entry.getKey();
+
+            Set<Instruction> allowedDeadFromThisInstruction = Sets.newHashSet();
+            Label starterLabel = entry.getValue();
+            collectAllowedDeadInstructions(starter, starterLabel, allowedDeadFromThisInstruction, allowDeadStoppers);
+            allowedDeadInstructions.addAll(allowedDeadFromThisInstruction);
         }
         return allowedDeadInstructions;
     }
     
-    private void collectAllowedDeadInstructions(Instruction allowedDeadInstruction, Set<Instruction> instructionSet, Set<Instruction> stopAllowDeadInstructions) {
-        if (instructionSet.contains(allowedDeadInstruction) || stopAllowDeadInstructions.contains(allowedDeadInstruction)) return;
-        if (((InstructionImpl)allowedDeadInstruction).isDead()) {
-            instructionSet.add(allowedDeadInstruction);
-            for (Instruction instruction : allowedDeadInstruction.getNextInstructions()) {
-                collectAllowedDeadInstructions(instruction, instructionSet, stopAllowDeadInstructions);
+    private static void collectAllowedDeadInstructions(
+            @NotNull Instruction current,
+            @NotNull Label starterLabel,
+            @NotNull Set<Instruction> collectedDeadInstructions,
+            @NotNull Map<Instruction, Collection<Label>> allowDeadStoppers
+    ) {
+
+        if (collectedDeadInstructions.contains(current)) return;
+        Collection<Label> allowDeadLabels = allowDeadStoppers.get(current);
+        boolean isStopper = allowDeadLabels != null && allowDeadLabels.contains(starterLabel);
+        if (isStopper) return;
+
+        if (((InstructionImpl)current).isDead()) {
+            collectedDeadInstructions.add(current);
+            for (Instruction instruction : current.getNextInstructions()) {
+                collectAllowedDeadInstructions(instruction, starterLabel, collectedDeadInstructions, allowDeadStoppers);
             }
         }
     }