diff --git a/packages/compiler-cli/src/ngtsc/util/src/typescript.ts b/packages/compiler-cli/src/ngtsc/util/src/typescript.ts
index f8ca1fb619..63af2e8206 100644
--- a/packages/compiler-cli/src/ngtsc/util/src/typescript.ts
+++ b/packages/compiler-cli/src/ngtsc/util/src/typescript.ts
@@ -92,7 +92,9 @@ export function isExported(node: DeclarationNode): boolean {
       topLevel.modifiers.some(modifier => modifier.kind === ts.SyntaxKind.ExportKeyword);
 }
 
-export function getRootDirs(host: ts.CompilerHost, options: ts.CompilerOptions): AbsoluteFsPath[] {
+export function getRootDirs(
+    host: Pick<ts.CompilerHost, 'getCurrentDirectory'|'getCanonicalFileName'>,
+    options: ts.CompilerOptions): AbsoluteFsPath[] {
   const rootDirs: string[] = [];
   if (options.rootDirs !== undefined) {
     rootDirs.push(...options.rootDirs);
diff --git a/packages/language-service/ivy/BUILD.bazel b/packages/language-service/ivy/BUILD.bazel
index 044974cee2..37b67f6c39 100644
--- a/packages/language-service/ivy/BUILD.bazel
+++ b/packages/language-service/ivy/BUILD.bazel
@@ -18,6 +18,7 @@ ts_library(
         "//packages/compiler-cli/src/ngtsc/shims",
         "//packages/compiler-cli/src/ngtsc/typecheck",
         "//packages/compiler-cli/src/ngtsc/typecheck/api",
+        "//packages/compiler-cli/src/ngtsc/util",
         "@npm//@types/node",
         "@npm//typescript",
     ],
diff --git a/packages/language-service/ivy/adapters.ts b/packages/language-service/ivy/adapters.ts
index c95d326688..bd02eaa562 100644
--- a/packages/language-service/ivy/adapters.ts
+++ b/packages/language-service/ivy/adapters.ts
@@ -10,8 +10,9 @@
 
 import {ConfigurationHost} from '@angular/compiler-cli';
 import {NgCompilerAdapter} from '@angular/compiler-cli/src/ngtsc/core/api';
-import {absoluteFrom, AbsoluteFsPath, FileStats, PathSegment, PathString} from '@angular/compiler-cli/src/ngtsc/file_system';
+import {AbsoluteFsPath, FileStats, PathSegment, PathString} from '@angular/compiler-cli/src/ngtsc/file_system';
 import {isShim} from '@angular/compiler-cli/src/ngtsc/shims';
+import {getRootDirs} from '@angular/compiler-cli/src/ngtsc/util/src/typescript';
 import * as p from 'path';
 import * as ts from 'typescript/lib/tsserverlibrary';
 
@@ -27,7 +28,7 @@ export class LanguageServiceAdapter implements NgCompilerAdapter {
   private readonly templateVersion = new Map<string, string>();
 
   constructor(private readonly project: ts.server.Project) {
-    this.rootDirs = project.getCompilationSettings().rootDirs?.map(absoluteFrom) || [];
+    this.rootDirs = getRootDirs(this, project.getCompilationSettings());
   }
 
   isShim(sf: ts.SourceFile): boolean {