Support reusing source library builders

Change-Id: Idc884e9c733bad0cb3e15be3cbaf248e8371196a
Reviewed-on: https://dart-review.googlesource.com/28663
Reviewed-by: Jens Johansen <[email protected]>

Author: peter-ahe-google

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

@@ -187,7 +187,7 @@ class KernelTarget extends TargetImplementation {
     List<ClassBuilder> result = <ClassBuilder>[];
     loader.builders.forEach((Uri uri, LibraryBuilder library) {
       library.forEach((String name, Builder member) {
-        if (member is KernelClassBuilder) {
+        if (member is ClassBuilder) {
           result.add(member);
         }
       });
@@ -380,20 +380,22 @@ class KernelTarget extends TargetImplementation {
   void installDefaultSupertypes() {
     Class objectClass = this.objectClass;
     loader.builders.forEach((Uri uri, LibraryBuilder library) {
-      library.forEach((String name, Builder builder) {
-        if (builder is SourceClassBuilder) {
-          Class cls = builder.target;
-          if (cls != objectClass) {
-            cls.supertype ??= objectClass.asRawSupertype;
-            builder.supertype ??= new KernelNamedTypeBuilder("Object", null)
-              ..bind(objectClassBuilder);
+      if (library.loader == loader) {
+        library.forEach((String name, Builder builder) {
+          if (builder is SourceClassBuilder) {
+            Class cls = builder.target;
+            if (cls != objectClass) {
+              cls.supertype ??= objectClass.asRawSupertype;
+              builder.supertype ??= new KernelNamedTypeBuilder("Object", null)
+                ..bind(objectClassBuilder);
+            }
+            if (builder.isMixinApplication) {
+              cls.mixedInType = builder.mixedInType
+                  .buildSupertype(library, builder.charOffset, builder.fileUri);
+            }
           }
-          if (builder.isMixinApplication) {
-            cls.mixedInType = builder.mixedInType
-                .buildSupertype(library, builder.charOffset, builder.fileUri);
-          }
-        }
-      });
+        });
+      }
     });
     ticker.logMs("Installed Object as implicit superclass");
   }

pkg/front_end/lib/src/fasta/loader.dart

@@ -142,8 +142,10 @@ abstract class Loader<L> {
   Future<Null> buildBodies() async {
     assert(coreLibrary != null);
     for (LibraryBuilder library in builders.values) {
-      currentUriForCrashReporting = library.uri;
-      await buildBody(library);
+      if (library.loader == this) {
+        currentUriForCrashReporting = library.uri;
+        await buildBody(library);
+      }
     }
     currentUriForCrashReporting = null;
     logSummary(templateSourceBodySummary);

pkg/front_end/lib/src/fasta/source/source_loader.dart

@@ -209,20 +209,21 @@ class SourceLoader<L> extends Loader<L> {
   void resolveParts() {
     List<Uri> parts = <Uri>[];
     builders.forEach((Uri uri, LibraryBuilder library) {
-      if (library is SourceLibraryBuilder) {
-        if (library.isPart) {
-          library.validatePart();
+      if (library.loader == this) {
+        SourceLibraryBuilder sourceLibrary = library;
+        if (sourceLibrary.isPart) {
+          sourceLibrary.validatePart();
           parts.add(uri);
         } else {
-          library.includeParts();
+          sourceLibrary.includeParts();
         }
       }
     });
     parts.forEach(builders.remove);
     ticker.logMs("Resolved parts");
 
     builders.forEach((Uri uri, LibraryBuilder library) {
-      if (library is SourceLibraryBuilder) {
+      if (library.loader == this) {
         library.applyPatches();
       }
     });
@@ -233,8 +234,9 @@ class SourceLoader<L> extends Loader<L> {
     Set<LibraryBuilder> exporters = new Set<LibraryBuilder>();
     Set<LibraryBuilder> exportees = new Set<LibraryBuilder>();
     builders.forEach((Uri uri, LibraryBuilder library) {
-      if (library is SourceLibraryBuilder) {
-        library.buildInitialScopes();
+      if (library.loader == this) {
+        SourceLibraryBuilder sourceLibrary = library;
+        sourceLibrary.buildInitialScopes();
       }
       if (library.exporters.isNotEmpty) {
         exportees.add(library);
@@ -266,10 +268,18 @@ class SourceLoader<L> extends Loader<L> {
       }
     } while (wasChanged);
     builders.forEach((Uri uri, LibraryBuilder library) {
-      if (library is SourceLibraryBuilder) {
-        library.addImportsToScope();
+      if (library.loader == this) {
+        SourceLibraryBuilder sourceLibrary = library;
+        sourceLibrary.addImportsToScope();
       }
     });
+    for (LibraryBuilder exportee in exportees) {
+      // TODO(ahe): Change how we track exporters. Currently, when a library
+      // (exporter) exports another library (exportee) we add a reference to
+      // exporter to exportee. This creates a reference in the wrong direction
+      // and can lead to memory leaks.
+      exportee.exporters.clear();
+    }
     ticker.logMs("Computed library scopes");
     // debugPrintExports();
   }
@@ -314,47 +324,59 @@ class SourceLoader<L> extends Loader<L> {
   void finishDeferredLoadTearoffs() {
     int count = 0;
     builders.forEach((Uri uri, LibraryBuilder library) {
-      count += library.finishDeferredLoadTearoffs();
+      if (library.loader == this) {
+        count += library.finishDeferredLoadTearoffs();
+      }
     });
     ticker.logMs("Finished deferred load tearoffs $count");
   }
 
   void finishStaticInvocations() {
     int count = 0;
     builders.forEach((Uri uri, LibraryBuilder library) {
-      count += library.finishStaticInvocations();
+      if (library.loader == this) {
+        count += library.finishStaticInvocations();
+      }
     });
     ticker.logMs("Finished static invocations $count");
   }
 
   void resolveConstructors() {
     int count = 0;
     builders.forEach((Uri uri, LibraryBuilder library) {
-      count += library.resolveConstructors(null);
+      if (library.loader == this) {
+        count += library.resolveConstructors(null);
+      }
     });
     ticker.logMs("Resolved $count constructors");
   }
 
   void finishTypeVariables(ClassBuilder object) {
     int count = 0;
     builders.forEach((Uri uri, LibraryBuilder library) {
-      count += library.finishTypeVariables(object);
+      if (library.loader == this) {
+        count += library.finishTypeVariables(object);
+      }
     });
     ticker.logMs("Resolved $count type-variable bounds");
   }
 
   void finishNativeMethods() {
     int count = 0;
     builders.forEach((Uri uri, LibraryBuilder library) {
-      count += library.finishNativeMethods();
+      if (library.loader == this) {
+        count += library.finishNativeMethods();
+      }
     });
     ticker.logMs("Finished $count native methods");
   }
 
   void finishPatchMethods() {
     int count = 0;
     builders.forEach((Uri uri, LibraryBuilder library) {
-      count += library.finishPatchMethods();
+      if (library.loader == this) {
+        count += library.finishPatchMethods();
+      }
     });
     ticker.logMs("Finished $count patch methods");
   }
@@ -497,8 +519,9 @@ class SourceLoader<L> extends Loader<L> {
 
   void buildProgram() {
     builders.forEach((Uri uri, LibraryBuilder library) {
-      if (library is SourceLibraryBuilder) {
-        L target = library.build(coreLibrary);
+      if (library.loader == this) {
+        SourceLibraryBuilder sourceLibrary = library;
+        L target = sourceLibrary.build(coreLibrary);
         if (!library.isPatch) {
           libraries.add(target);
         }
@@ -517,7 +540,9 @@ class SourceLoader<L> extends Loader<L> {
   void checkOverrides(List<SourceClassBuilder> sourceClasses) {
     assert(hierarchy != null);
     for (SourceClassBuilder builder in sourceClasses) {
-      builder.checkOverrides(hierarchy);
+      if (builder.library.loader == this) {
+        builder.checkOverrides(hierarchy);
+      }
     }
     ticker.logMs("Checked overrides");
   }
@@ -539,7 +564,7 @@ class SourceLoader<L> extends Loader<L> {
         instrumentation,
         target.strongMode);
     builders.forEach((Uri uri, LibraryBuilder library) {
-      if (library is SourceLibraryBuilder) {
+      if (library.loader == this) {
         library.prepareTopLevelInference(library, null);
       }
     });
@@ -574,7 +599,7 @@ class SourceLoader<L> extends Loader<L> {
     typeInferenceEngine.finishTopLevelInitializingFormals();
     if (instrumentation != null) {
       builders.forEach((Uri uri, LibraryBuilder library) {
-        if (library is SourceLibraryBuilder) {
+        if (library.loader == this) {
           library.instrumentTopLevelInference(instrumentation);
         }
       });