feat(ivy): first steps towards ngtsc mode (#23455)

This commit adds a new compiler pipeline that isn't dependent on global
analysis, referred to as 'ngtsc'. This new compiler is accessed by
running ngc with "enableIvy" set to "ngtsc". It reuses the same initialization
logic but creates a new implementation of Program which does not perform the
global-level analysis that AngularCompilerProgram does. It will be the
foundation for the production Ivy compiler.

PR Close #23455

packages/compiler-cli/src/transformers/program.ts

@@ -15,6 +15,7 @@ import * as ts from 'typescript';
 import {TypeCheckHost, translateDiagnostics} from '../diagnostics/translate_diagnostics';
 import {compareVersions} from '../diagnostics/typescript_version';
 import {MetadataCollector, ModuleMetadata, createBundleIndexHost} from '../metadata/index';
+import {NgtscProgram} from '../ngtsc/program';
 
 import {CompilerHost, CompilerOptions, CustomTransformers, DEFAULT_ERROR_CODE, Diagnostic, DiagnosticMessageChain, EmitFlags, LazyRoute, LibrarySummary, Program, SOURCE, TsEmitArguments, TsEmitCallback, TsMergeEmitResultsCallback} from './api';
 import {CodeGenerator, TsCompilerAotCompilerTypeCheckHostAdapter, getOriginalReferences} from './compiler_host';
@@ -286,6 +287,9 @@ class AngularCompilerProgram implements Program {
     emitCallback?: TsEmitCallback,
     mergeEmitResultsCallback?: TsMergeEmitResultsCallback,
   } = {}): ts.EmitResult {
+    if (this.options.enableIvy === 'ngtsc') {
+      throw new Error('Cannot run legacy compiler in ngtsc mode');
+    }
     return this.options.enableIvy === true ? this._emitRender3(parameters) :
                                              this._emitRender2(parameters);
   }
@@ -903,6 +907,9 @@ export function createProgram({rootNames, options, host, oldProgram}: {
   options: CompilerOptions,
   host: CompilerHost, oldProgram?: Program
 }): Program {
+  if (options.enableIvy === 'ngtsc') {
+    return new NgtscProgram(rootNames, options, host, oldProgram);
+  }
   return new AngularCompilerProgram(rootNames, options, host, oldProgram);
 }