Make MinimizeExitPoints a peephole optimization.

This allows us to add it to the PeepholeOptimziationsPass, and remove it as an independent compiler pass. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=132586900
google · Sep 9, 2016 · 168485e · 168485e
1 parent 59e7c63
commit 168485e
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Showing 4 changed files with 11 additions and 34 deletions.
diff --git a/src/com/google/javascript/jscomp/DefaultPassConfig.java b/src/com/google/javascript/jscomp/DefaultPassConfig.java
@@ -941,8 +941,6 @@ private List<PassFactory> getCodeRemovingPasses() {
     }
 
     if (options.foldConstants) {
-      // These used to be one pass.
-      passes.add(minimizeExitPoints);
       passes.add(peepholeOptimizations);
     }
 
@@ -1493,6 +1491,7 @@ private static CompilerPass createPeepholeOptimizationsPass(AbstractCompiler com
     final boolean late = false;
     final boolean useTypesForOptimization =  compiler.getOptions().useTypesForOptimization;
     return new PeepholeOptimizationsPass(compiler,
+          new MinimizeExitPoints(compiler),
           new PeepholeMinimizeConditions(late, useTypesForOptimization),
           new PeepholeSubstituteAlternateSyntax(late),
           new PeepholeReplaceKnownMethods(late),
@@ -2156,17 +2155,6 @@ protected CompilerPass create(AbstractCompiler compiler) {
     }
   };
 
-  /**
-   * Perform local control flow optimizations.
-   */
-  private final PassFactory minimizeExitPoints =
-      new PassFactory("minimizeExitPoints", false) {
-    @Override
-    protected CompilerPass create(AbstractCompiler compiler) {
-      return new MinimizeExitPoints(compiler);
-    }
-  };
-
   /**
    * Use data flow analysis to remove dead branches.
    */

diff --git a/src/com/google/javascript/jscomp/MinimizeExitPoints.java b/src/com/google/javascript/jscomp/MinimizeExitPoints.java
@@ -16,14 +16,12 @@
 
 package com.google.javascript.jscomp;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
-import com.google.javascript.jscomp.NodeTraversal.AbstractShallowCallback;
-import com.google.javascript.jscomp.NodeTraversal.FunctionCallback;
 import com.google.javascript.rhino.IR;
 import com.google.javascript.rhino.Node;
 import com.google.javascript.rhino.Token;
 import com.google.javascript.rhino.jstype.TernaryValue;
-
 import javax.annotation.Nullable;
 
 /**
@@ -32,28 +30,20 @@
  *
  * @author johnlenz@google.com (John Lenz)
  */
-class MinimizeExitPoints extends AbstractShallowCallback implements CompilerPass {
+class MinimizeExitPoints extends AbstractPeepholeOptimization {
   AbstractCompiler compiler;
 
   MinimizeExitPoints(AbstractCompiler compiler) {
     this.compiler = compiler;
   }
 
-  @Override
+  @VisibleForTesting
-  public void process(Node externs, Node root) {
+  final CompilerPass asCompilerPass() {
-    NodeTraversal.traverseChangedFunctions(compiler, new FunctionCallback() {
+    return new PeepholeOptimizationsPass(compiler, this);
-        @Override
-        public void enterFunction(AbstractCompiler compiler, Node root) {
-          if (root.isFunction()) {
-            root = root.getLastChild();
-          }
-          NodeTraversal.traverseEs6(compiler, root, MinimizeExitPoints.this);
-        }
-    });
   }
 
   @Override
-  public void visit(NodeTraversal t, Node n, Node parent) {
+  Node optimizeSubtree(Node n) {
     switch (n.getToken()) {
       case LABEL:
         tryMinimizeExits(
@@ -78,8 +68,6 @@ public void visit(NodeTraversal t, Node n, Node parent) {
         break;
 
       case BLOCK:
-        // The traversal starts at the function block so `parent` will be null, so we use
-        // getParent here.
         if (n.getParent() != null && n.getParent().isFunction()) {
           tryMinimizeExits(n, Token.RETURN, null);
         }
@@ -94,6 +82,7 @@ public void visit(NodeTraversal t, Node n, Node parent) {
       default:
         break;
     }
+    return n;
   }
 
   /**

diff --git a/test/com/google/javascript/jscomp/CreateSyntheticBlocksTest.java b/test/com/google/javascript/jscomp/CreateSyntheticBlocksTest.java
@@ -43,13 +43,13 @@ protected CompilerPass getProcessor(final Compiler compiler) {
       public void process(Node externs, Node js) {
         new CreateSyntheticBlocks(compiler, START_MARKER, END_MARKER).process(
             externs, js);
-        new MinimizeExitPoints(compiler).process(externs, js);
+        new MinimizeExitPoints(compiler).asCompilerPass().process(externs, js);
         new PeepholeOptimizationsPass(compiler,
             new PeepholeRemoveDeadCode(),
             new PeepholeMinimizeConditions(true /* late */, false /* useTypes */),
             new PeepholeFoldConstants(true, false))
             .process(externs, js);
-        new MinimizeExitPoints(compiler).process(externs, js);
+        new MinimizeExitPoints(compiler).asCompilerPass().process(externs, js);
         new Denormalize(compiler).process(externs, js);
       }
     };

diff --git a/test/com/google/javascript/jscomp/MinimizeExitPointsTest.java b/test/com/google/javascript/jscomp/MinimizeExitPointsTest.java
@@ -22,7 +22,7 @@
 public final class MinimizeExitPointsTest extends CompilerTestCase {
   @Override
   protected CompilerPass getProcessor(final Compiler compiler) {
-    return new MinimizeExitPoints(compiler);
+    return new MinimizeExitPoints(compiler).asCompilerPass();
   }
 
   @Override