fix(compiler): cache external reference resolution (#21359)

Cache reference resolution for external references as finding the declaration of a symbol is expensive and does not change for a program once created. This resolves a signficant performance regression in the langauge service. PR Close #21359

Author: chuckjaz

packages/compiler/src/aot/static_reflector.ts

@@ -47,6 +47,7 @@ export class StaticReflector implements CompileReflector {
  private methodCache = new Map<StaticSymbol, {[key: string]: boolean}>();
  private staticCache = new Map<StaticSymbol, string[]>();
  private conversionMap = new Map<StaticSymbol, (context: StaticSymbol, args: any[]) => any>();
+ private resolvedExternalReferences = new Map<string, StaticSymbol>();
  private injectionToken: StaticSymbol;
  private opaqueToken: StaticSymbol;
  ROUTES: StaticSymbol;
@@ -81,13 +82,22 @@ export class StaticReflector implements CompileReflector {
  }
 
  resolveExternalReference(ref: o.ExternalReference, containingFile?: string): StaticSymbol {
+ let key: string|undefined = undefined;
+ if (!containingFile) {
+ key = `${ref.moduleName}:${ref.name}`;
+ const declarationSymbol = this.resolvedExternalReferences.get(key);
+ if (declarationSymbol) return declarationSymbol;
+ }
  const refSymbol =
  this.symbolResolver.getSymbolByModule(ref.moduleName !, ref.name !, containingFile);
  const declarationSymbol = this.findSymbolDeclaration(refSymbol);
  if (!containingFile) {
  this.symbolResolver.recordModuleNameForFileName(refSymbol.filePath, ref.moduleName !);
  this.symbolResolver.recordImportAs(declarationSymbol, refSymbol);
  }
+ if (key) {
+ this.resolvedExternalReferences.set(key, declarationSymbol);
+ }
  return declarationSymbol;
  }