perf(turbopack/swc): Add icf to builds, reducing binary size

[bgw]

Decreases macos binary size by ~4.1%, and linux binary size by ~1.5% on arm64.

Unlike LTO, this does not appear to have any meaningful impact on build times.

Rustc reported some minor benefit to execution time (better code cache effects) when they enabled this, though I suspect it's too small to easily measure.

I'm only enabling this on the release builds used by CI. Release builds made with some other scripts, like pack-next will not do this.

[bgw]

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• perf(turbopack/swc): Add icf to builds, reducing binary size #75497 👈 (View in Graphite)
• refactor(cargo): Clean up cargo build configs #75498
• canary

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[ijjk]

Failing test suites

Commit: 428b83d

pnpm test-start-turbo test/e2e/app-dir/rewrite-headers/rewrite-headers.test.ts (turbopack)

• rewrite-headers > middleware rewrite external Prefetch RSC (/hello/vercel) > should have the expected headers
• rewrite-headers > middleware rewrite external RSC (/hello/vercel) > should have the expected headers

Expand output

● rewrite-headers › middleware rewrite external RSC (/hello/vercel) › should have the expected headers

expect(received).toEqual(expected) // deep equality

- Expected  - 1
+ Received  + 1

  Object {
-   "x-nextjs-rewritten-path": null,
+   "x-nextjs-rewritten-path": "/home",
    "x-nextjs-rewritten-query": null,
  }

  404 |         })
  405 |
> 406 |         expect(headers).toEqual(expected)
      |                         ^
  407 |       })
  408 |     }
  409 |   )

  at Object.toEqual (e2e/app-dir/rewrite-headers/rewrite-headers.test.ts:406:25)

● rewrite-headers › middleware rewrite external Prefetch RSC (/hello/vercel) › should have the expected headers

expect(received).toEqual(expected) // deep equality

- Expected  - 1
+ Received  + 1

  Object {
-   "x-nextjs-rewritten-path": null,
+   "x-nextjs-rewritten-path": "/home",
    "x-nextjs-rewritten-query": null,
  }

  404 |         })
  405 |
> 406 |         expect(headers).toEqual(expected)
      |                         ^
  407 |       })
  408 |     }
  409 |   )

  at Object.toEqual (e2e/app-dir/rewrite-headers/rewrite-headers.test.ts:406:25)

Read more about building and testing Next.js in contributing.md.

[ijjk]

Stats from current PR

Default Build

General

	vercel/next.js canary	vercel/next.js bgw/cargo-icf	Change
buildDuration	20.5s	20.7s	⚠️ +174ms
buildDurationCached	17.7s	14.8s	N/A
nodeModulesSize	391 MB	391 MB	N/A
nextStartRea..uration (ms)	497ms	501ms	N/A

Client Bundles (main, webpack)

	vercel/next.js canary	vercel/next.js bgw/cargo-icf	Change
5306-HASH.js gzip	54 kB	53.9 kB	N/A
8276.HASH.js gzip	169 B	168 B	N/A
8377-HASH.js gzip	5.46 kB	5.46 kB	N/A
bccd1874-HASH.js gzip	52.9 kB	52.9 kB	N/A
framework-HASH.js gzip	57.5 kB	57.5 kB	N/A
main-app-HASH.js gzip	241 B	242 B	N/A
main-HASH.js gzip	34.5 kB	34.4 kB	N/A
webpack-HASH.js gzip	1.71 kB	1.71 kB	N/A
Overall change	0 B	0 B	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js bgw/cargo-icf	Change
polyfills-HASH.js gzip	39.4 kB	39.4 kB	✓
Overall change	39.4 kB	39.4 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js bgw/cargo-icf	Change
_app-HASH.js gzip	193 B	193 B	✓
_error-HASH.js gzip	193 B	193 B	✓
amp-HASH.js gzip	512 B	510 B	N/A
css-HASH.js gzip	343 B	342 B	N/A
dynamic-HASH.js gzip	1.84 kB	1.84 kB	✓
edge-ssr-HASH.js gzip	265 B	265 B	✓
head-HASH.js gzip	363 B	362 B	N/A
hooks-HASH.js gzip	393 B	392 B	N/A
image-HASH.js gzip	4.59 kB	4.58 kB	N/A
index-HASH.js gzip	268 B	268 B	✓
link-HASH.js gzip	2.35 kB	2.35 kB	N/A
routerDirect..HASH.js gzip	328 B	328 B	✓
script-HASH.js gzip	397 B	397 B	✓
withRouter-HASH.js gzip	323 B	326 B	N/A
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Overall change	3.59 kB	3.59 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js bgw/cargo-icf	Change
_buildManifest.js gzip	748 B	747 B	N/A
Overall change	0 B	0 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js bgw/cargo-icf	Change
index.html gzip	523 B	522 B	N/A
link.html gzip	538 B	537 B	N/A
withRouter.html gzip	519 B	519 B	✓
Overall change	519 B	519 B	✓

Edge SSR bundle Size

	vercel/next.js canary	vercel/next.js bgw/cargo-icf	Change
edge-ssr.js gzip	129 kB	129 kB	N/A
page.js gzip	210 kB	210 kB	N/A
Overall change	0 B	0 B	✓

Middleware size

	vercel/next.js canary	vercel/next.js bgw/cargo-icf	Change
middleware-b..fest.js gzip	669 B	665 B	N/A
middleware-r..fest.js gzip	155 B	156 B	N/A
middleware.js gzip	31.3 kB	31.3 kB	N/A
edge-runtime..pack.js gzip	844 B	844 B	✓
Overall change	844 B	844 B	✓

Next Runtimes

	vercel/next.js canary	vercel/next.js bgw/cargo-icf	Change
app-page-exp...dev.js gzip	386 kB	386 kB	N/A
app-page-exp..prod.js gzip	132 kB	132 kB	✓
app-page-tur..prod.js gzip	145 kB	145 kB	✓
app-page-tur..prod.js gzip	141 kB	141 kB	✓
app-page.run...dev.js gzip	373 kB	373 kB	N/A
app-page.run..prod.js gzip	128 kB	128 kB	✓
app-route-ex...dev.js gzip	39.2 kB	39.2 kB	✓
app-route-ex..prod.js gzip	25.6 kB	25.6 kB	✓
app-route-tu..prod.js gzip	25.6 kB	25.6 kB	✓
app-route-tu..prod.js gzip	25.4 kB	25.4 kB	✓
app-route.ru...dev.js gzip	40.8 kB	40.8 kB	✓
app-route.ru..prod.js gzip	25.4 kB	25.4 kB	✓
dist_client_...dev.js gzip	356 B	356 B	✓
dist_client_...dev.js gzip	349 B	349 B	✓
pages-api-tu..prod.js gzip	9.69 kB	9.69 kB	✓
pages-api.ru...dev.js gzip	11.8 kB	11.8 kB	✓
pages-api.ru..prod.js gzip	9.68 kB	9.68 kB	✓
pages-turbo...prod.js gzip	21.9 kB	21.9 kB	✓
pages.runtim...dev.js gzip	31.5 kB	31.5 kB	✓
pages.runtim..prod.js gzip	21.9 kB	21.9 kB	✓
server.runti..prod.js gzip	60.2 kB	60.2 kB	✓
Overall change	895 kB	895 kB	✓

build cache

	vercel/next.js canary	vercel/next.js bgw/cargo-icf	Change
0.pack gzip	2.1 MB	2.1 MB	N/A
index.pack gzip	75.8 kB	74.8 kB	N/A
Overall change	0 B	0 B	✓

Diff details

Diff for main-HASH.js

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Diff for app-page-exp..ntime.dev.js

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Diff for app-page.runtime.dev.js

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Commit: 428b83d