diff --git a/packages/compiler/src/frontend/dts-paths.ts b/packages/compiler/src/frontend/dts-paths.ts
index 3b2f32413..009d1c333 100644
--- a/packages/compiler/src/frontend/dts-paths.ts
+++ b/packages/compiler/src/frontend/dts-paths.ts
@@ -34,6 +34,31 @@ export function packageShimRoot(): string {
     : join(installedDeclarationRoot, "shims");
 }
 
+/** The directories of files scriptc itself ships, each with the prefix
+ * that names its files independently of where scriptc is installed
+ * (compilerOwnedFileName). IR artifacts spell source locations in them this
+ * way (serializeModuleParts). */
+export function compilerOwnedFileRoots(): readonly { from: string; to: string }[] {
+  return [{ from: tsgoPath(packageShimRoot()) + "/", to: "scriptc:shims/" }];
+}
+
+/** The name of a file scriptc itself ships (a package shim or one of the
+ * shipped declaration files) that does not depend on where scriptc is
+ * installed: `scriptc:shims/<path below the shim root>` or
+ * `scriptc:<declaration file name>`. Null for every other file. Names and
+ * artifacts that would otherwise spell the installation's absolute path use
+ * it, so two installations of one compiler emit the same output. */
+export function compilerOwnedFileName(file: string): string | null {
+  const path = tsgoPath(file);
+  for (const { from, to } of compilerOwnedFileRoots()) {
+    if (path.startsWith(from)) return to + path.slice(from.length);
+  }
+  for (const declaration of [ambientDtsPath(), overridesDtsPath(), fallbackDtsPath()]) {
+    if (path === declaration) return `scriptc:${path.slice(path.lastIndexOf("/") + 1)}`;
+  }
+  return null;
+}
+
 /** Path of the shipped ambient declarations — the always-shipped CORE
  * (comptime, setTimeout). Part of EVERY program scriptc
  * builds, the project-world preflight program included. */
diff --git a/packages/compiler/src/frontend/lowering/lowerer.ts b/packages/compiler/src/frontend/lowering/lowerer.ts
index 67ea1d2ee..4c417e86e 100644
--- a/packages/compiler/src/frontend/lowering/lowerer.ts
+++ b/packages/compiler/src/frontend/lowering/lowerer.ts
@@ -185,7 +185,7 @@ export { newFnCtx, type FnCtx } from "./function-context.js";
  */
 import { dirname, relative, resolve } from "node:path";
 import { bindingSource } from "../binding-source.js";
-import { tsgoPath } from "../dts-paths.js";
+import { compilerOwnedFileName, tsgoPath } from "../dts-paths.js";
 import * as ts from "../ts7/adapter.js";
 import { isBundledShimForwarder } from "../package-shims.js";
 import { erasedTypeOnlyImport } from "../type-only-imports.js";
@@ -3210,13 +3210,14 @@ export class Lowerer {
   /** Structural source positions (structural-positions.ts) for names that
    * stay the same when unrelated code moves. */
   /** Files are named by their path relative to the entry's directory, so
-   * names do not depend on where the program sits, and default library
-   * files by their base name: two checkers install them in different
-   * directories. */
+   * names do not depend on where the program sits, default library files
+   * by their base name (two checkers install them in different
+   * directories), and the files scriptc ships by their name inside scriptc,
+   * so names do not depend on where scriptc is installed either. */
   readonly positions = new StructuralPositions((sf) =>
     this.program.isSourceFileDefaultLibrary(sf)
       ? `lib:${sf.fileName.slice(sf.fileName.lastIndexOf("/") + 1)}`
-      : relative(dirname(this.entry.fileName), sf.fileName),
+      : (compilerOwnedFileName(sf.fileName) ?? relative(dirname(this.entry.fileName), sf.fileName)),
   );
 
   /** The outermost node whose token span is exactly `loc`, or null. */
@@ -3248,7 +3249,10 @@ export class Lowerer {
    * before it. */
   closureName(loc: SrcLoc, suffix = "", prefix = "%fn"): string {
     const node = this.nodeAtLoc(loc);
-    const where = node === null ? `${loc.file}:${loc.start}:${loc.end}` : this.positions.of(node);
+    const where =
+      node === null
+        ? `${compilerOwnedFileName(loc.file) ?? loc.file}:${loc.start}:${loc.end}`
+        : this.positions.of(node);
     const key = `${prefix}|${this.closureRoot}|${where}|${suffix}`;
     const first = keyedHelperName(this, prefix, key);
     const seen = this.closureNameCounts.get(first) ?? 0;
@@ -3389,8 +3393,18 @@ export class Lowerer {
       if (interned.has(fn.name)) this.sharedHelpers.add(fn);
     if (this.sharedHelpers.size === 0) return;
     const shared = new Map([...this.sharedHelpers].map((fn) => [fn.name, fn]));
-    const earlier = (left: SrcLoc, right: SrcLoc): boolean =>
-      left.file < right.file || (left.file === right.file && left.start < right.start);
+    // Files scriptc ships compare by their name inside scriptc, so the
+    // choice does not depend on where scriptc is installed.
+    const fileKeys = new Map<string, string>();
+    const fileKey = (file: string): string => {
+      let key = fileKeys.get(file);
+      if (key === undefined) fileKeys.set(file, (key = compilerOwnedFileName(file) ?? file));
+      return key;
+    };
+    const earlier = (left: SrcLoc, right: SrcLoc): boolean => {
+      if (left.file === right.file) return left.start < right.start;
+      return fileKey(left.file) < fileKey(right.file);
+    };
     // The earliest use of each shared helper outside the shared helpers, and
     // which shared helpers each shared helper uses.
     const uses = new Map<string, SrcLoc>();
diff --git a/packages/compiler/src/index.ts b/packages/compiler/src/index.ts
index f0f19a408..daa5af366 100644
--- a/packages/compiler/src/index.ts
+++ b/packages/compiler/src/index.ts
@@ -126,6 +126,7 @@ import { moduleRuntimeFeatures } from "./ir/runtime-features.js";
 import { serializeModuleParts } from "./ir/serialize.js";
 import { readTextParts, writeTextParts } from "./text-parts.js";
 import { validateModule } from "./ir/validate.js";
+import { compilerOwnedFileRoots } from "./frontend/dts-paths.js";
 import { loadProgram } from "./frontend/program-node.js";
 import { runFrontend, type FrontendFactory } from "./frontend/pipeline.js";
 import {
@@ -785,7 +786,7 @@ async function prepareExecutableInput(
 
   if (outputKind === "ir") {
     await mkdir(dirname(opts.outPath), { recursive: true });
-    await writeTextParts(opts.outPath, serializeModuleParts(mod));
+    await writeTextParts(opts.outPath, serializeModuleParts(mod, compilerOwnedFileRoots()));
     return { ok: true, artifact: { kind: "ir", path: opts.outPath } };
   }
 
@@ -885,7 +886,7 @@ async function prepareExecutableInput(
   if (opts.emitIr) {
     irPath = defaultSourcePaths.ir;
     irSourcePath = privateSiblingPath(irPath, "ir");
-    await writeTextParts(irSourcePath, serializeModuleParts(mod));
+    await writeTextParts(irSourcePath, serializeModuleParts(mod, compilerOwnedFileRoots()));
   }
 
   const nativeFeatures = executableNativeFeatures(mod, backend, opts.optimization ?? "release");
@@ -1986,7 +1987,7 @@ async function emitSemanticLibraryHit(
   let irPath: string | undefined;
   if (opts.emitIr) {
     irPath = join(opts.outDir, `${stem}.lib.ir.json`);
-    await writeTextParts(irPath, serializeModuleParts(mod));
+    await writeTextParts(irPath, serializeModuleParts(mod, compilerOwnedFileRoots()));
   }
   await compileLibraryNative(profile, llvmPath, archivePath, opts.sanitize ?? false, hit.native);
   timing("native-archive");
@@ -2272,7 +2273,7 @@ async function compileLibraryTracked(
   let irPath: string | undefined;
   if (opts.emitIr) {
     irPath = join(opts.outDir, `${stem}.lib.ir.json`);
-    await writeTextParts(irPath, serializeModuleParts(mod));
+    await writeTextParts(irPath, serializeModuleParts(mod, compilerOwnedFileRoots()));
   }
 
   const nativeFeatures = libraryNativeFeatures(mod, profile.emission);
diff --git a/packages/compiler/src/ir/serialize.test.ts b/packages/compiler/src/ir/serialize.test.ts
index 8345ab10a..c24e1f198 100644
--- a/packages/compiler/src/ir/serialize.test.ts
+++ b/packages/compiler/src/ir/serialize.test.ts
@@ -198,3 +198,24 @@ test("byte decoding keeps the whole-document errors and version refusal", () =>
   const sentinel = text.replace('"nan"', '"future"');
   expect(() => deserializeModuleBytes(Buffer.from(sentinel))).toThrow("Invalid IR number sentinel");
 });
+
+test("file roots respell the source locations under them and nothing else", () => {
+  const mod = numbers([1, 2]);
+  const shim = { file: '/opt/scriptc "a"/shims/pkg/index.ts', start: 3, end: 4 };
+  const other = { file: "/opt/elsewhere/shims/pkg/index.ts", start: 5, end: 6 };
+  const body = mod.functions[0]!.body as IrStmt[];
+  body.push(
+    { kind: "exprStmt", expr: { kind: "numLit", value: 3, type: F64, loc: shim }, loc: shim },
+    { kind: "exprStmt", expr: { kind: "numLit", value: 4, type: F64, loc: other }, loc: other },
+  );
+  const roots = [{ from: '/opt/scriptc "a"/shims/', to: "scriptc:shims/" }];
+  const relocated = deserializeModule(serializeModuleParts(mod, roots).join(""));
+  const files = (relocated.functions[0]!.body as IrStmt[]).map((stmt) => stmt.loc.file);
+  expect(files).toEqual([
+    "numbers.ts",
+    "numbers.ts",
+    "scriptc:shims/pkg/index.ts",
+    "/opt/elsewhere/shims/pkg/index.ts",
+  ]);
+  expect(serializeModuleParts(mod).join("")).toBe(serializeModule(mod, true));
+});
diff --git a/packages/compiler/src/ir/serialize.ts b/packages/compiler/src/ir/serialize.ts
index ca5eb955e..314f258d6 100644
--- a/packages/compiler/src/ir/serialize.ts
+++ b/packages/compiler/src/ir/serialize.ts
@@ -46,11 +46,41 @@ function encodeFunction(fn: IrFunction): string | undefined {
   return ordinaryNumbers(fn) ? JSON.stringify(fn) : JSON.stringify(fn, encodeNumber);
 }
 
+/** A directory whose source location files an IR artifact names by a
+ * prefix of its own: a location file `from + rest` serializes as
+ * `to + rest`. */
+export interface SerializedFileRoot {
+  from: string;
+  to: string;
+}
+
+/** Respells the source location files under `roots` in serialized parts.
+ * A location's file is the first member of its JSON object, and the
+ * escaped spelling of a path prefix is the prefix of the escaped path. */
+function relocateFiles(parts: string[], roots: readonly SerializedFileRoot[]): string[] {
+  const needles = roots.map(({ from, to }) => ({
+    from: `"file":${JSON.stringify(from).slice(0, -1)}`,
+    to: `"file":${JSON.stringify(to).slice(0, -1)}`,
+  }));
+  return parts.map((part) =>
+    needles.reduce(
+      (text, { from, to }) => (text.includes(from) ? text.replaceAll(from, to) : text),
+      part,
+    ),
+  );
+}
+
 /** The compact encoding as ordered parts: the module header up to the
  * function array, one part per function (with separate comma parts), and the
  * header's remainder. Concatenating the parts yields exactly
- * `serializeModule(mod, true)`; writers stream them to disk in batches. */
-export function serializeModuleParts(mod: IrModule): string[] {
+ * `serializeModule(mod, true)`; writers stream them to disk in batches.
+ * `fileRoots` respells the source locations in those directories, so
+ * artifacts do not depend on where the compiler that wrote them is
+ * installed. */
+export function serializeModuleParts(
+  mod: IrModule,
+  fileRoots: readonly SerializedFileRoot[] = [],
+): string[] {
   // A replacer reads through live native views. Serializing the complete
   // function array through one view refreshes every function capsule for
   // each element, making large compiler artifacts quadratic. The sentinel
@@ -65,7 +95,7 @@ export function serializeModuleParts(mod: IrModule): string[] {
     parts.push(encodeFunction(fn) ?? "null");
   }
   parts.push("]" + header.slice(offset + slot.length));
-  return parts;
+  return fileRoots.length === 0 ? parts : relocateFiles(parts, fileRoots);
 }
 
 /** Compiler artifacts use compact JSON; API consumers can retain the
diff --git a/packages/compiler/src/native/prepare.ts b/packages/compiler/src/native/prepare.ts
index 42ff404bd..f7f399f80 100644
--- a/packages/compiler/src/native/prepare.ts
+++ b/packages/compiler/src/native/prepare.ts
@@ -27,6 +27,7 @@ import {
   type FrontendInputExclusions,
   trackedReadFile,
 } from "../frontend/input-tracker.js";
+import { compilerOwnedFileRoots } from "../frontend/dts-paths.js";
 import { provenanceSources } from "../frontend/provenance-registry.js";
 import { processFork } from "../frontend/process-fork.js";
 import { tokenEquivalentSource } from "../frontend/token-equivalence.js";
@@ -377,7 +378,7 @@ export function prepareNativeExecutable(
   if (irInput !== "") timing("ir-input");
   const ir =
     outputKind === "ir" || options.emitIr
-      ? batchTextParts(serializeModuleParts(prepared.mod))
+      ? batchTextParts(serializeModuleParts(prepared.mod, compilerOwnedFileRoots()))
       : null;
   timing("ir-serialize");
   const llvm =
@@ -510,7 +511,9 @@ export function prepareNativeLibrary(
   const input: NativeExecutableInput = {
     ok: true,
     llvm,
-    ir: options.emitIr ? batchTextParts(serializeModuleParts(prepared.mod)) : null,
+    ir: options.emitIr
+      ? batchTextParts(serializeModuleParts(prepared.mod, compilerOwnedFileRoots()))
+      : null,
     sidecarJson: prepared.sidecarJson,
     features: executableLinkFeatures(prepared.mod),
     sources: [...prepared.sourceTexts],