When --dependency_mode is set to STRICT or LOOSE, order dependencies in a deterministic depth-first order from entry points.

Avoids a full parse on every input when CommonJS module processing is enabled.
ES6 and CommonJS modules no longer generate synthetic goog.require and goog.provide calls.
ES6 Module Transpilation no longer depends on Closure-Library primitives.

Closes #2641

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=172126284

Author: ChadKillingsworth

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

@@ -64,7 +64,6 @@
 import java.io.Serializable;
 import java.util.AbstractSet;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -1750,7 +1749,19 @@ Node parseInputs() {
                   options.moduleResolutionMode,
                   processJsonInputs(inputs));
         }
+      } else {
+        // Use an empty module loader if we're not actually dealing with modules.
+        this.moduleLoader = ModuleLoader.EMPTY;
+      }
 
+      if (options.getDependencyOptions().needsManagement()) {
+        findDependenciesFromEntryPoints(
+            options.getLanguageIn().toFeatureSet().has(Feature.MODULES),
+            options.processCommonJSModules,
+            options.transformAMDToCJSModules);
+      } else if (options.needsTranspilationOf(Feature.MODULES)
+          || options.transformAMDToCJSModules
+          || options.processCommonJSModules) {
         if (options.getLanguageIn().toFeatureSet().has(Feature.MODULES)) {
           parsePotentialModules(inputs);
         }
@@ -1783,12 +1794,12 @@ Node parseInputs() {
           }
         }
 
-        if (!inputsToRewrite.isEmpty()) {
-          forceToEs6Modules(inputsToRewrite.values());
+        for (CompilerInput input : inputsToRewrite.values()) {
+          forceInputToPathBasedModule(
+              input,
+              options.getLanguageIn().toFeatureSet().has(Feature.MODULES),
+              options.processCommonJSModules);
         }
-      } else {
-        // Use an empty module loader if we're not actually dealing with modules.
-        this.moduleLoader = ModuleLoader.EMPTY;
       }
 
       orderInputs();
@@ -1896,6 +1907,142 @@ void orderInputs() {
     }
   }
 
+  /**
+   * Find dependencies by recursively traversing each dependency of an input starting with the entry
+   * points. Causes a full parse of each file, but since the file is reachable by walking the graph,
+   * this would be required in later compilation passes regardless.
+   *
+   * <p>Inputs which are not reachable during graph traversal will be dropped.
+   *
+   * <p>If the dependency mode is set to LOOSE, inputs for which the deps package did not find a
+   * provide statement or detect as a module will be treated as entry points.
+   */
+  void findDependenciesFromEntryPoints(
+      boolean supportEs6Modules, boolean supportCommonJSModules, boolean supportAmdModules) {
+    hoistExterns();
+    List<CompilerInput> entryPoints = new ArrayList<>();
+    Map<String, CompilerInput> inputsByProvide = new HashMap<>();
+    Map<String, CompilerInput> inputsByIdentifier = new HashMap<>();
+    for (CompilerInput input : inputs) {
+      if (!options.getDependencyOptions().shouldDropMoochers() && input.getProvides().isEmpty()) {
+        entryPoints.add(input);
+      }
+      inputsByIdentifier.put(
+          ModuleIdentifier.forFile(input.getPath().toString()).toString(), input);
+      for (String provide : input.getProvides()) {
+        if (!provide.startsWith("module$")) {
+          inputsByProvide.put(provide, input);
+        }
+      }
+    }
+    for (ModuleIdentifier moduleIdentifier : options.getDependencyOptions().getEntryPoints()) {
+      CompilerInput input = inputsByIdentifier.get(moduleIdentifier.toString());
+      if (input != null) {
+        entryPoints.add(input);
+      }
+    }
+
+    Set<CompilerInput> workingInputSet = new HashSet<>(inputs);
+    List<CompilerInput> orderedInputs = new ArrayList<>();
+    for (CompilerInput entryPoint : entryPoints) {
+      orderedInputs.addAll(
+          depthFirstDependenciesFromInput(
+              entryPoint,
+              /* wasImportedByModule = */ false,
+              workingInputSet,
+              inputsByIdentifier,
+              inputsByProvide,
+              supportEs6Modules,
+              supportCommonJSModules,
+              supportAmdModules));
+    }
+
+    // TODO(ChadKillingsworth) Move this into the standard compilation passes
+    if (supportCommonJSModules) {
+      for (CompilerInput input : orderedInputs) {
+        new ProcessCommonJSModules(this)
+            .process(/* externs */ null, input.getAstRoot(this), /* forceModuleDetection */ false);
+      }
+    }
+  }
+
+  /** For a given input, order it's dependencies in a depth first traversal */
+  private List<CompilerInput> depthFirstDependenciesFromInput(
+      CompilerInput input,
+      boolean wasImportedByModule,
+      Set<CompilerInput> inputs,
+      Map<String, CompilerInput> inputsByIdentifier,
+      Map<String, CompilerInput> inputsByProvide,
+      boolean supportEs6Modules,
+      boolean supportCommonJSModules,
+      boolean supportAmdModules) {
+    List<CompilerInput> orderedInputs = new ArrayList<>();
+    if (!inputs.remove(input)) {
+      // It's possible for a module to be included as both a script
+      // and a module in the same compilation. In these cases, it should
+      // be forced to be a module.
+      if (wasImportedByModule && input.getJsModuleType() == CompilerInput.ModuleType.NONE) {
+        forceInputToPathBasedModule(input, supportEs6Modules, supportCommonJSModules);
+      }
+
+      return orderedInputs;
+    }
+
+    if (supportAmdModules) {
+      new TransformAMDToCJSModule(this).process(null, input.getAstRoot(this));
+    }
+
+    FindModuleDependencies findDeps =
+        new FindModuleDependencies(this, supportEs6Modules, supportCommonJSModules);
+    findDeps.process(input.getAstRoot(this));
+
+    // If this input was imported by another module, it is itself a module
+    // so we force it to be detected as such.
+    if (wasImportedByModule && input.getJsModuleType() == CompilerInput.ModuleType.NONE) {
+      forceInputToPathBasedModule(input, supportEs6Modules, supportCommonJSModules);
+    }
+
+    for (String requiredNamespace : input.getRequires()) {
+      CompilerInput requiredInput = null;
+      boolean requiredByModuleImport = false;
+      if (inputsByProvide.containsKey(requiredNamespace)) {
+        requiredInput = inputsByProvide.get(requiredNamespace);
+      } else if (inputsByIdentifier.containsKey(requiredNamespace)) {
+        requiredByModuleImport = true;
+        requiredInput = inputsByIdentifier.get(requiredNamespace);
+      }
+
+      if (requiredInput != null) {
+        orderedInputs.addAll(
+            depthFirstDependenciesFromInput(
+                requiredInput,
+                requiredByModuleImport,
+                inputs,
+                inputsByIdentifier,
+                inputsByProvide,
+                supportEs6Modules,
+                supportCommonJSModules,
+                supportAmdModules));
+      }
+    }
+    orderedInputs.add(input);
+    return orderedInputs;
+  }
+
+  private void forceInputToPathBasedModule(
+      CompilerInput input, boolean supportEs6Modules, boolean supportCommonJSModules) {
+
+    if (supportEs6Modules) {
+      FindModuleDependencies findDeps =
+          new FindModuleDependencies(this, supportEs6Modules, supportCommonJSModules);
+      findDeps.convertToEs6Module(input.getAstRoot(this));
+      input.setJsModuleType(CompilerInput.ModuleType.ES6);
+    } else if (supportCommonJSModules) {
+      new ProcessCommonJSModules(this).process(null, input.getAstRoot(this), true);
+      input.setJsModuleType(CompilerInput.ModuleType.COMMONJS);
+    }
+  }
+
   /**
    * Hoists inputs with the @externs annotation into the externs list.
    */
@@ -2005,18 +2152,6 @@ Map<String, String> processJsonInputs(List<CompilerInput> inputsToProcess) {
     return rewriteJson.getPackageJsonMainEntries();
   }
 
-  void forceToEs6Modules(Collection<CompilerInput> inputsToProcess) {
-    for (CompilerInput input : inputsToProcess) {
-      input.setCompiler(this);
-      input.addProvide(input.getPath().toModuleName());
-      Node root = input.getAstRoot(this);
-      if (root == null) {
-        continue;
-      }
-      Es6RewriteModules moduleRewriter = new Es6RewriteModules(this);
-      moduleRewriter.forceToEs6Module(root);
-    }
-  }
 
   private List<CompilerInput> parsePotentialModules(List<CompilerInput> inputsToProcess) {
     List<CompilerInput> filteredInputs = new ArrayList<>();
@@ -2055,7 +2190,7 @@ void processAMDAndCommonJSModules() {
         new TransformAMDToCJSModule(this).process(null, root);
       }
       if (options.processCommonJSModules) {
-        ProcessCommonJSModules cjs = new ProcessCommonJSModules(this, true);
+        ProcessCommonJSModules cjs = new ProcessCommonJSModules(this);
         cjs.process(null, root);
       }
     }

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

@@ -61,6 +61,9 @@ public class CompilerInput implements SourceAst, DependencyInfo {
   private DependencyInfo dependencyInfo;
   private final List<String> extraRequires = new ArrayList<>();
   private final List<String> extraProvides = new ArrayList<>();
+  private final List<String> orderedRequires = new ArrayList<>();
+  private boolean hasFullParseDependencyInfo = false;
+  private ModuleType jsModuleType = ModuleType.NONE;
 
   // An AbstractCompiler for doing parsing.
   // We do not want to persist this across serialized state.
@@ -160,6 +163,10 @@ public void setCompiler(AbstractCompiler compiler) {
   /** Gets a list of types depended on by this input. */
   @Override
   public Collection<String> getRequires() {
+    if (hasFullParseDependencyInfo) {
+      return orderedRequires;
+    }
+
     return getDependencyInfo().getRequires();
   }
 
@@ -191,19 +198,36 @@ Collection<String> getKnownProvides() {
         extraProvides);
   }
 
-  // TODO(nicksantos): Remove addProvide/addRequire/removeRequire once
-  // there is better support for discovering non-closure dependencies.
-
   /**
-   * Registers a type that this input defines.
+   * Registers a type that this input defines. Includes both explicitly declared namespaces via
+   * goog.provide and goog.module calls as well as implicit namespaces provided by module rewriting.
    */
   public void addProvide(String provide) {
     extraProvides.add(provide);
   }
 
-  /**
-   * Registers a type that this input depends on.
-   */
+  /** Registers a type that this input depends on in the order seen in the file. */
+  public boolean addOrderedRequire(String require) {
+    if (!orderedRequires.contains(require)) {
+      orderedRequires.add(require);
+      return true;
+    }
+    return false;
+  }
+
+  public void setHasFullParseDependencyInfo(boolean hasFullParseDependencyInfo) {
+    this.hasFullParseDependencyInfo = hasFullParseDependencyInfo;
+  }
+
+  public ModuleType getJsModuleType() {
+    return jsModuleType;
+  }
+
+  public void setJsModuleType(ModuleType moduleType) {
+    jsModuleType = moduleType;
+  }
+
+  /** Registers a type that this input depends on. */
   public void addRequire(String require) {
     extraRequires.add(require);
   }
@@ -493,4 +517,11 @@ public void reset() {
     this.module = null;
     this.ast.clearAst();
   }
+
+  public enum ModuleType {
+    NONE,
+    GOOG_MODULE,
+    ES6,
+    COMMONJS
+  }
 }

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

@@ -20,7 +20,7 @@
 
 import java.io.Serializable;
 import java.util.Collection;
-import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.Set;
 
 /**
@@ -43,7 +43,7 @@ public final class DependencyOptions implements Serializable {
   private boolean sortDependencies = false;
   private boolean pruneDependencies = false;
   private boolean dropMoochers = false;
-  private final Set<ModuleIdentifier> entryPoints = new HashSet<>();
+  private final Set<ModuleIdentifier> entryPoints = new LinkedHashSet<>();
 
   /**
    * Enables or disables dependency sorting mode.