Introduce mechanism for running a subset of JSC transpilation and optimization passes

PiperOrigin-RevId: 716405590

Author: rahul-kamat

src/com/google/javascript/jscomp/CheckExtraRequiresPassConfig.java

@@ -46,7 +46,7 @@ protected PassListBuilder getChecks() {
   }
 
   @Override
-  protected PassListBuilder getOptimizations() {
+  protected PassListBuilder getOptimizations(OptimizationPasses optimizationPasses) {
     return new PassListBuilder(options);
   }
 }

src/com/google/javascript/jscomp/Compiler.java

@@ -46,6 +46,7 @@
 import com.google.javascript.jscomp.JSChunkGraph.ChunkDependenceException;
 import com.google.javascript.jscomp.JSChunkGraph.MissingChunkException;
 import com.google.javascript.jscomp.NodeTraversal.AbstractPreOrderCallback;
+import com.google.javascript.jscomp.PassConfig.OptimizationPasses;
 import com.google.javascript.jscomp.SortingErrorManager.ErrorReportGenerator;
 import com.google.javascript.jscomp.base.format.SimpleFormat;
 import com.google.javascript.jscomp.colors.ColorRegistry;
@@ -3003,7 +3004,8 @@ boolean endsWith(String suffix) {
   void performTranspilationAndOptimizations() {
     checkState(options.shouldOptimize());
     // getOptimizations() also includes transpilation passes
-    ImmutableList<PassFactory> optimizations = getPassConfig().getOptimizations().build();
+    ImmutableList<PassFactory> optimizations =
+        getPassConfig().getOptimizations(OptimizationPasses.ALL).build();
     if (optimizations.isEmpty()) {
       return;
     }

src/com/google/javascript/jscomp/ConformancePassConfig.java

@@ -43,7 +43,7 @@ protected PassListBuilder getChecks() {
   }
 
   @Override
-  protected PassListBuilder getOptimizations() {
+  protected PassListBuilder getOptimizations(OptimizationPasses optimizationPasses) {
     return new PassListBuilder(options);
   }
 }

src/com/google/javascript/jscomp/DefaultPassConfig.java

@@ -498,7 +498,7 @@ protected PassListBuilder getChecks() {
   }
 
   @Override
-  protected PassListBuilder getOptimizations() {
+  protected PassListBuilder getOptimizations(OptimizationPasses optimizationPasses) {
     PassListBuilder passes = new PassListBuilder(options);
     // At this point all checks have been done.
     if (options.exportTestFunctions) {

src/com/google/javascript/jscomp/LintPassConfig.java

@@ -60,7 +60,7 @@ protected PassListBuilder getChecks() {
   }
 
   @Override
-  protected PassListBuilder getOptimizations() {
+  protected PassListBuilder getOptimizations(OptimizationPasses optimizationPasses) {
     return new PassListBuilder(options);
   }
 

src/com/google/javascript/jscomp/PassConfig.java

@@ -61,7 +61,18 @@ protected PassListBuilder getTranspileOnlyPasses() {
    * <p>Optimization passes revolve around producing smaller and faster code. They should always run
    * after checking passes.
    */
-  protected abstract PassListBuilder getOptimizations();
+  protected abstract PassListBuilder getOptimizations(OptimizationPasses optimizationPasses);
+
+  /**
+   * Different ways to split optimization passes. Passing one of these enum options to
+   * getOptimizations() to tell to configure which list of stage 2 passes to return.
+   */
+  public enum OptimizationPasses {
+    ALL,
+    // TODO(user): Enable these in a follow-up CL.
+    // FIRST_HALF, // Passes from beginning of stage 2 until before the early optimization loop.
+    // SECOND_HALF, // Passes from the early optimization loop until the end of stage 2.
+  }
 
   /**
    * Gets the finalization passes to run.
@@ -75,7 +86,7 @@ protected PassListBuilder getTranspileOnlyPasses() {
   GraphvizGraph getPassGraph() {
     LinkedDirectedGraph<String, String> graph = LinkedDirectedGraph.createWithoutAnnotations();
     Iterable<PassFactory> allPasses =
-        Iterables.concat(getChecks().build(), getOptimizations().build());
+        Iterables.concat(getChecks().build(), getOptimizations(OptimizationPasses.ALL).build());
     String lastPass = null;
     String loopStart = null;
     for (PassFactory pass : allPasses) {
@@ -131,8 +142,8 @@ protected PassListBuilder getChecks() {
     }
 
     @Override
-    protected PassListBuilder getOptimizations() {
-      return delegate.getOptimizations();
+    protected PassListBuilder getOptimizations(OptimizationPasses optimizationPasses) {
+      return delegate.getOptimizations(optimizationPasses);
     }
 
     @Override