…lutter#186693)

Reverts: [Ship gen_snapshot for linux-arm64 hosts targeting
Android](flutter#182552)

Initiated by: @eyebrowsoffire

Reason for reverting: We do not have any bots capable of servicing this
builder, and it is breaking our releases as well as `flutter precache
--all`

Original PR Author: @dbebawy

Reviewed By: @reidbaker

The original PR description is provided below:

## Summary

Enable Android **profile** and **release** builds on ARM64 Linux hosts
(AWS Graviton, GCP Tau T2A, self-hosted ARM64 runners, etc.), which
currently fail because `gen_snapshot` is only shipped for `linux-x64`
hosts.

Supersedes flutter#182275 and flutter#182276 — combined into a single atomic commit
per reviewer feedback.

### Engine changes

- **`BUILD.gn`**: Make `gen_snapshot` and `analyze_snapshot` zip output
names host-architecture-aware (`linux-arm64.zip` vs `linux-x64.zip`)
using explicit `if (host_os == "linux" && host_cpu == "arm64")`
branching, matching the existing pattern for mac/windows.
- **`linux_arm64_android_aot_engine.json`** (new): CI builder config
following the secondary builder pattern (matching
`mac_android_aot_engine.json`). Only produces host-specific archives —
shared artifacts (`artifacts.zip`, `symbols.zip`, embedding/abi jars)
continue to be produced by the existing x64 Linux builder.
- **`.ci.yaml`**: New builder entry with `bringup: true`, `os=Linux`,
`cpu=arm64`.

### Framework changes

- **`flutter_cache.dart`**: Convert `_linuxBinaryDirs` from a hardcoded
`linux-x64` const list to a function parameterized by host architecture,
using the existing `cache.getHostPlatformArchName()` pattern from
`LinuxEngineArtifacts`.
- **`artifacts.dart`**: Clean up stale TODO comment — replace with
accurate explanation of why `darwin-arm64` is remapped to `darwin-x64`
(universal binary). No Linux remapping needed since Linux ships native
binaries per host architecture.
- **Tests**: Add tests for both x64 and arm64 host artifact resolution
in `cache_test.dart` and `artifacts_test.dart`, following the existing
`LinuxEngineArtifacts` test pattern.

### Infrastructure notes

- The builder is set to `bringup: true` to allow stabilization before
becoming a blocking builder.
- Requires ARM64 Linux machines in the LUCI swarming pool (`os=Linux` +
`cpu=arm64`).
- 8 build configurations: {arm, arm64, x64, riscv64} × {profile,
release}. This matches the x64 Linux builder's target coverage. The
macOS equivalent has 6 builds (no riscv64).
- Uses RBE (`--rbe`) for remote compilation.

Fixes flutter#75864
Fixes flutter#168980

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

## Test plan

### Verified by PR CI (x64 hosts)

- [x] `linux_android_aot_engine` (x64) passed — `BUILD.gn` change still
produces `linux-x64.zip` correctly
- [x] `mac_android_aot_engine` passed — `darwin-x64.zip` unaffected
- [x] `windows_android_aot_engine` passed — `windows-x64.zip` unaffected
- [x] `ci.yaml validation` passed — builder JSON and `.ci.yaml` entry
are structurally valid
- [x] Archive paths are unique across all builder configs (verified
locally)
- [x] Unit tests pass for `AndroidGenSnapshotArtifacts.getBinaryDirs()`
returning `linux-x64` entries on x64 hosts and `linux-arm64` entries on
arm64 hosts
- [x] Unit tests pass for `getArtifactPath` resolving `gen_snapshot` to
correct host-architecture path on both x64 and arm64 Linux

### Requires ARM64 Linux hardware (post-bringup)

The new `linux_arm64_android_aot_engine` builder is `bringup: true` and
does not run on PR checks. The `BUILD.gn` code path (`host_cpu ==
"arm64"`) is only exercised on ARM64 hosts. The following need to be
validated once the builder runs on ARM64 infrastructure:

- [ ] `gen_snapshot` compiles and links on ARM64 Linux
- [ ] CI builder produces `linux-arm64.zip` archives for all Android
target CPUs (arm, arm64, x64, riscv64) in both profile and release modes
- [ ] `analyze_snapshot` produces `analyze-snapshot-linux-arm64.zip` for
64-bit targets
- [ ] Artifacts download correctly on an ARM64 Linux host via `flutter
precache`

---------

Co-authored-by: Jackson Gardner <jacksongardner@google.com>

…lutter#186693)

Reverts: [Ship gen_snapshot for linux-arm64 hosts targeting
Android](flutter#182552)

Initiated by: @eyebrowsoffire

Reason for reverting: We do not have any bots capable of servicing this
builder, and it is breaking our releases as well as `flutter precache
--all`

Original PR Author: @dbebawy

Reviewed By: @reidbaker

The original PR description is provided below:

## Summary

Enable Android **profile** and **release** builds on ARM64 Linux hosts
(AWS Graviton, GCP Tau T2A, self-hosted ARM64 runners, etc.), which
currently fail because `gen_snapshot` is only shipped for `linux-x64`
hosts.

Supersedes flutter#182275 and flutter#182276 — combined into a single atomic commit
per reviewer feedback.

### Engine changes

- **`BUILD.gn`**: Make `gen_snapshot` and `analyze_snapshot` zip output
names host-architecture-aware (`linux-arm64.zip` vs `linux-x64.zip`)
using explicit `if (host_os == "linux" && host_cpu == "arm64")`
branching, matching the existing pattern for mac/windows.
- **`linux_arm64_android_aot_engine.json`** (new): CI builder config
following the secondary builder pattern (matching
`mac_android_aot_engine.json`). Only produces host-specific archives —
shared artifacts (`artifacts.zip`, `symbols.zip`, embedding/abi jars)
continue to be produced by the existing x64 Linux builder.
- **`.ci.yaml`**: New builder entry with `bringup: true`, `os=Linux`,
`cpu=arm64`.

### Framework changes

- **`flutter_cache.dart`**: Convert `_linuxBinaryDirs` from a hardcoded
`linux-x64` const list to a function parameterized by host architecture,
using the existing `cache.getHostPlatformArchName()` pattern from
`LinuxEngineArtifacts`.
- **`artifacts.dart`**: Clean up stale TODO comment — replace with
accurate explanation of why `darwin-arm64` is remapped to `darwin-x64`
(universal binary). No Linux remapping needed since Linux ships native
binaries per host architecture.
- **Tests**: Add tests for both x64 and arm64 host artifact resolution
in `cache_test.dart` and `artifacts_test.dart`, following the existing
`LinuxEngineArtifacts` test pattern.

### Infrastructure notes

- The builder is set to `bringup: true` to allow stabilization before
becoming a blocking builder.
- Requires ARM64 Linux machines in the LUCI swarming pool (`os=Linux` +
`cpu=arm64`).
- 8 build configurations: {arm, arm64, x64, riscv64} × {profile,
release}. This matches the x64 Linux builder's target coverage. The
macOS equivalent has 6 builds (no riscv64).
- Uses RBE (`--rbe`) for remote compilation.

Fixes flutter#75864
Fixes flutter#168980

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

## Test plan

### Verified by PR CI (x64 hosts)

- [x] `linux_android_aot_engine` (x64) passed — `BUILD.gn` change still
produces `linux-x64.zip` correctly
- [x] `mac_android_aot_engine` passed — `darwin-x64.zip` unaffected
- [x] `windows_android_aot_engine` passed — `windows-x64.zip` unaffected
- [x] `ci.yaml validation` passed — builder JSON and `.ci.yaml` entry
are structurally valid
- [x] Archive paths are unique across all builder configs (verified
locally)
- [x] Unit tests pass for `AndroidGenSnapshotArtifacts.getBinaryDirs()`
returning `linux-x64` entries on x64 hosts and `linux-arm64` entries on
arm64 hosts
- [x] Unit tests pass for `getArtifactPath` resolving `gen_snapshot` to
correct host-architecture path on both x64 and arm64 Linux

### Requires ARM64 Linux hardware (post-bringup)

The new `linux_arm64_android_aot_engine` builder is `bringup: true` and
does not run on PR checks. The `BUILD.gn` code path (`host_cpu ==
"arm64"`) is only exercised on ARM64 hosts. The following need to be
validated once the builder runs on ARM64 infrastructure:

- [ ] `gen_snapshot` compiles and links on ARM64 Linux
- [ ] CI builder produces `linux-arm64.zip` archives for all Android
target CPUs (arm, arm64, x64, riscv64) in both profile and release modes
- [ ] `analyze_snapshot` produces `analyze-snapshot-linux-arm64.zip` for
64-bit targets
- [ ] Artifacts download correctly on an ARM64 Linux host via `flutter
precache`

---------

Co-authored-by: Jackson Gardner <jacksongardner@google.com>

…roid" (#186818)

This is a cherry-pick of this revert, which is needed because the change that was reverted caused a breakage in our release build.

Reverts: [Ship gen_snapshot for linux-arm64 hosts targeting Android](#182552)

Initiated by: @eyebrowsoffire

Reason for reverting: We do not have any bots capable of servicing this builder, and it is breaking our releases as well as `flutter precache --all`

Original PR Author: @dbebawy

Reviewed By: @reidbaker

The original PR description is provided below:

## Summary

Enable Android **profile** and **release** builds on ARM64 Linux hosts (AWS Graviton, GCP Tau T2A, self-hosted ARM64 runners, etc.), which currently fail because `gen_snapshot` is only shipped for `linux-x64` hosts.

Supersedes #182275 and #182276 — combined into a single atomic commit per reviewer feedback.

### Engine changes

- **`BUILD.gn`**: Make `gen_snapshot` and `analyze_snapshot` zip output names host-architecture-aware (`linux-arm64.zip` vs `linux-x64.zip`) using explicit `if (host_os == "linux" && host_cpu == "arm64")` branching, matching the existing pattern for mac/windows.
- **`linux_arm64_android_aot_engine.json`** (new): CI builder config following the secondary builder pattern (matching
`mac_android_aot_engine.json`). Only produces host-specific archives — shared artifacts (`artifacts.zip`, `symbols.zip`, embedding/abi jars) continue to be produced by the existing x64 Linux builder.
- **`.ci.yaml`**: New builder entry with `bringup: true`, `os=Linux`, `cpu=arm64`.

### Framework changes

- **`flutter_cache.dart`**: Convert `_linuxBinaryDirs` from a hardcoded `linux-x64` const list to a function parameterized by host architecture, using the existing `cache.getHostPlatformArchName()` pattern from `LinuxEngineArtifacts`.
- **`artifacts.dart`**: Clean up stale TODO comment — replace with accurate explanation of why `darwin-arm64` is remapped to `darwin-x64` (universal binary). No Linux remapping needed since Linux ships native binaries per host architecture.
- **Tests**: Add tests for both x64 and arm64 host artifact resolution in `cache_test.dart` and `artifacts_test.dart`, following the existing `LinuxEngineArtifacts` test pattern.

### Infrastructure notes

- The builder is set to `bringup: true` to allow stabilization before becoming a blocking builder.
- Requires ARM64 Linux machines in the LUCI swarming pool (`os=Linux` + `cpu=arm64`).
- 8 build configurations: {arm, arm64, x64, riscv64} × {profile, release}. This matches the x64 Linux builder's target coverage. The macOS equivalent has 6 builds (no riscv64).
- Uses RBE (`--rbe`) for remote compilation.

Fixes #75864 Fixes #168980

https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

## Test plan

### Verified by PR CI (x64 hosts)

### Requires ARM64 Linux hardware (post-bringup)

The new `linux_arm64_android_aot_engine` builder is `bringup: true` and does not run on PR checks. The `BUILD.gn` code path (`host_cpu == "arm64"`) is only exercised on ARM64 hosts. The following need to be validated once the builder runs on ARM64 infrastructure:

---------

<!--
Thanks for filing a pull request!
Reviewers are typically assigned within a week of filing a request.
To learn more about code review, see our documentation on Tree Hygiene: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
-->

*Replace this paragraph with a description of what this PR is changing or adding, and why. Consider including before/after screenshots.*

*List which issues are fixed by this PR. You must list at least one issue. An issue is not required if the PR fixes something trivial like a typo.*

*If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].*

If this change needs to override an active code freeze, provide a comment explaining why. The code freeze workflow can be overridden by code reviewers. See pinned issues for any active code freezes with guidance.

**Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.

…lutter#186693)

Reverts: [Ship gen_snapshot for linux-arm64 hosts targeting
Android](flutter#182552)

Initiated by: @eyebrowsoffire

Reason for reverting: We do not have any bots capable of servicing this
builder, and it is breaking our releases as well as `flutter precache
--all`

Original PR Author: @dbebawy

Reviewed By: @reidbaker

The original PR description is provided below:

## Summary

Enable Android **profile** and **release** builds on ARM64 Linux hosts
(AWS Graviton, GCP Tau T2A, self-hosted ARM64 runners, etc.), which
currently fail because `gen_snapshot` is only shipped for `linux-x64`
hosts.

Supersedes flutter#182275 and flutter#182276 — combined into a single atomic commit
per reviewer feedback.

### Engine changes

- **`BUILD.gn`**: Make `gen_snapshot` and `analyze_snapshot` zip output
names host-architecture-aware (`linux-arm64.zip` vs `linux-x64.zip`)
using explicit `if (host_os == "linux" && host_cpu == "arm64")`
branching, matching the existing pattern for mac/windows.
- **`linux_arm64_android_aot_engine.json`** (new): CI builder config
following the secondary builder pattern (matching
`mac_android_aot_engine.json`). Only produces host-specific archives —
shared artifacts (`artifacts.zip`, `symbols.zip`, embedding/abi jars)
continue to be produced by the existing x64 Linux builder.
- **`.ci.yaml`**: New builder entry with `bringup: true`, `os=Linux`,
`cpu=arm64`.

### Framework changes

- **`flutter_cache.dart`**: Convert `_linuxBinaryDirs` from a hardcoded
`linux-x64` const list to a function parameterized by host architecture,
using the existing `cache.getHostPlatformArchName()` pattern from
`LinuxEngineArtifacts`.
- **`artifacts.dart`**: Clean up stale TODO comment — replace with
accurate explanation of why `darwin-arm64` is remapped to `darwin-x64`
(universal binary). No Linux remapping needed since Linux ships native
binaries per host architecture.
- **Tests**: Add tests for both x64 and arm64 host artifact resolution
in `cache_test.dart` and `artifacts_test.dart`, following the existing
`LinuxEngineArtifacts` test pattern.

### Infrastructure notes

- The builder is set to `bringup: true` to allow stabilization before
becoming a blocking builder.
- Requires ARM64 Linux machines in the LUCI swarming pool (`os=Linux` +
`cpu=arm64`).
- 8 build configurations: {arm, arm64, x64, riscv64} × {profile,
release}. This matches the x64 Linux builder's target coverage. The
macOS equivalent has 6 builds (no riscv64).
- Uses RBE (`--rbe`) for remote compilation.

Fixes flutter#75864
Fixes flutter#168980

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

## Test plan

### Verified by PR CI (x64 hosts)

- [x] `linux_android_aot_engine` (x64) passed — `BUILD.gn` change still
produces `linux-x64.zip` correctly
- [x] `mac_android_aot_engine` passed — `darwin-x64.zip` unaffected
- [x] `windows_android_aot_engine` passed — `windows-x64.zip` unaffected
- [x] `ci.yaml validation` passed — builder JSON and `.ci.yaml` entry
are structurally valid
- [x] Archive paths are unique across all builder configs (verified
locally)
- [x] Unit tests pass for `AndroidGenSnapshotArtifacts.getBinaryDirs()`
returning `linux-x64` entries on x64 hosts and `linux-arm64` entries on
arm64 hosts
- [x] Unit tests pass for `getArtifactPath` resolving `gen_snapshot` to
correct host-architecture path on both x64 and arm64 Linux

### Requires ARM64 Linux hardware (post-bringup)

The new `linux_arm64_android_aot_engine` builder is `bringup: true` and
does not run on PR checks. The `BUILD.gn` code path (`host_cpu ==
"arm64"`) is only exercised on ARM64 hosts. The following need to be
validated once the builder runs on ARM64 infrastructure:

- [ ] `gen_snapshot` compiles and links on ARM64 Linux
- [ ] CI builder produces `linux-arm64.zip` archives for all Android
target CPUs (arm, arm64, x64, riscv64) in both profile and release modes
- [ ] `analyze_snapshot` produces `analyze-snapshot-linux-arm64.zip` for
64-bit targets
- [ ] Artifacts download correctly on an ARM64 Linux host via `flutter
precache`

---------

Co-authored-by: Jackson Gardner <jacksongardner@google.com>

…s on linux-arm64 (flutter#186917)

flutter#182552 added support in the
Flutter tools for using a version of gen_snapshot that runs on
linux-arm64 hosts and targets Android devices.

However, the engine build infrastructure is not currently set up to
build this kind of gen_snapshot binary.

This PR contains changes needed to build engine artifacts on linux-arm64
machines. With this PR a linux-arm64 build environment can:
* run "gclient sync"
* build targets like zip_archives/android-arm64-profile/linux-arm64.zip
that were added in flutter#182552

Relands flutter#182552, reverted in flutter#186693 because the linux-arm64 builder
introduced in that PR had no bots in the LUCI pool and `flutter precache
--all` started 404'ing on missing `linux-arm64.zip` artifacts after the
beta cut.

This reland takes the direction @jtmcdole laid out on the original PR
on 2026-05-20 ("bypass the linux_arm64 tooling requirement since we
don't have official binaries in cipd"): the new
`linux_arm64_android_aot_engine` builder runs on the **existing
linux-x64 bot pool** and cross-compiles the host `gen_snapshot` binary
to linux-arm64. No new arm64 bots, no dependency on the
`flutter/android/sdk/all` CIPD package getting a linux-arm64 platform
build.

Engine code changes (+20 / -7 across 6 files):

- DEPS: drop `host_cpu == "arm64"` clause on the linux-arm64 clang CIPD
  download so x64 builders also fetch it (the clang binary is never
  executed; cross-compile happens via `--target=aarch64-linux-gnu`
  using the x64 clang).

- engine/src/build/config/BUILDCONFIG.gn: introduce `host_clang_cpu`,
  a new gn arg defaulting to `host_cpu`. Represents the CPU of
  build-time tools that run on the builder, distinct from `host_cpu`
  (the CPU the produced host binary runs on). No-op for native builds.

- engine/src/build/toolchain/linux/BUILD.gn: clang binary path is now
  keyed on `host_clang_cpu` instead of `host_cpu`, so the executable
  used during the build stays the x64 clang even when producing arm64
  output.

- engine/src/flutter/common/config.gni: the prebuilt Dart SDK path for
  build-time tooling (frontend server, kernel-to-AOT-snapshot) follows
  `host_clang_cpu`, so it resolves to the x64 dart-sdk on the builder.

- engine/src/flutter/shell/platform/android/BUILD.gn: zip names use
  `linux-\$host_cpu.zip` interpolation (matching what `flutter precache`
  looks for on arm64 hosts), and the gen_snapshot zip's deps now mirror
  what analyze_snapshot already does -- depend only on the host binary
  instead of `generate_snapshot_bins`, which runs gen_snapshot during
  the build (impossible when cross-compiled to aarch64).

- engine/src/flutter/tools/gn: add a `--host-cpu` flag, apply it in
  both `is_host_build()` and the cross-target (`else`) branches (the
  original PR only set host_cpu in the `is_host_build` branch, which is
  why `--host-cpu=arm64 --android` silently produced x86_64), and set
  `host_clang_cpu` to the build-machine CPU only when cross-compiling.

Plus CI plumbing for this reland:

- engine/src/flutter/ci/builders/linux_arm64_android_aot_engine.json:
  new builder config based on the reverted PR's version with four
  deltas: drone_dimensions drop `cpu=arm64` (runs on x64 pool), gn args
  add `--host-cpu arm64`, gclient_variables add
  `download_android_deps: false` and `download_jdk: false`, and ninja
  targets are the explicit `zip_archives/.../linux-arm64.zip` paths
  rather than the `flutter/shell/platform/android:gen_snapshot`
  umbrella target.

- engine/src/flutter/.ci.yaml: matching builder entry, same shape as
  the reverted PR's entry, `cpu=arm64` removed from drone_dimensions,
  `bringup: true`.

The framework changes from the reverted PR (flutter_tools cache /
artifact-path resolution) are intentionally NOT included here. They
land in a follow-up PR once the new builder has produced
`linux-arm64.zip` to GCS for at least one release. That sequencing is
the direct fix for the `flutter precache --all` 404 that triggered the
original revert: artifacts before manifest.

Empirically validated on native linux-x64 hardware (Debian 12 Docker,
real Intel x86_64, no QEMU):

- Original validation 2026-05-29 against `c7f49fe0` produced
  `linux-arm64.zip` (1.77 MB) and `analyze-snapshot-linux-arm64.zip`
  (2.8 MB).

- Fresh re-validation 2026-06-04 against `14c05c42` (then-current
  `main`): patches apply cleanly, `ninja clang_arm64/gen_snapshot`
  exits 0 in 6m37s `-j8`, output binary is ELF aarch64 PIE,
  glibc-linked, not Android bionic. Binary SHA256:
  898413a122ef33d42044fb0a2aa3259803f051ef9063b4d8ddd5e4eb7fa49cd0.

Runtime smoke test on real arm64 hardware (Graviton / arm64 VM / etc.)
is still owed before flipping `bringup: true` to false. QEMU user-mode
segfaults on gen_snapshot -- a known qemu limitation with executable
mmap / TLS-heavy runtimes, not a binary defect.

Fixes flutter#75864
Fixes flutter#168980

…lutter#186693)

Reverts: [Ship gen_snapshot for linux-arm64 hosts targeting
Android](flutter#182552)

Initiated by: @eyebrowsoffire

Reason for reverting: We do not have any bots capable of servicing this
builder, and it is breaking our releases as well as `flutter precache
--all`

Original PR Author: @dbebawy

Reviewed By: @reidbaker

The original PR description is provided below:

## Summary

Enable Android **profile** and **release** builds on ARM64 Linux hosts
(AWS Graviton, GCP Tau T2A, self-hosted ARM64 runners, etc.), which
currently fail because `gen_snapshot` is only shipped for `linux-x64`
hosts.

Supersedes flutter#182275 and flutter#182276 — combined into a single atomic commit
per reviewer feedback.

### Engine changes

- **`BUILD.gn`**: Make `gen_snapshot` and `analyze_snapshot` zip output
names host-architecture-aware (`linux-arm64.zip` vs `linux-x64.zip`)
using explicit `if (host_os == "linux" && host_cpu == "arm64")`
branching, matching the existing pattern for mac/windows.
- **`linux_arm64_android_aot_engine.json`** (new): CI builder config
following the secondary builder pattern (matching
`mac_android_aot_engine.json`). Only produces host-specific archives —
shared artifacts (`artifacts.zip`, `symbols.zip`, embedding/abi jars)
continue to be produced by the existing x64 Linux builder.
- **`.ci.yaml`**: New builder entry with `bringup: true`, `os=Linux`,
`cpu=arm64`.

### Framework changes

- **`flutter_cache.dart`**: Convert `_linuxBinaryDirs` from a hardcoded
`linux-x64` const list to a function parameterized by host architecture,
using the existing `cache.getHostPlatformArchName()` pattern from
`LinuxEngineArtifacts`.
- **`artifacts.dart`**: Clean up stale TODO comment — replace with
accurate explanation of why `darwin-arm64` is remapped to `darwin-x64`
(universal binary). No Linux remapping needed since Linux ships native
binaries per host architecture.
- **Tests**: Add tests for both x64 and arm64 host artifact resolution
in `cache_test.dart` and `artifacts_test.dart`, following the existing
`LinuxEngineArtifacts` test pattern.

### Infrastructure notes

- The builder is set to `bringup: true` to allow stabilization before
becoming a blocking builder.
- Requires ARM64 Linux machines in the LUCI swarming pool (`os=Linux` +
`cpu=arm64`).
- 8 build configurations: {arm, arm64, x64, riscv64} × {profile,
release}. This matches the x64 Linux builder's target coverage. The
macOS equivalent has 6 builds (no riscv64).
- Uses RBE (`--rbe`) for remote compilation.

Fixes flutter#75864
Fixes flutter#168980

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

## Test plan

### Verified by PR CI (x64 hosts)

- [x] `linux_android_aot_engine` (x64) passed — `BUILD.gn` change still
produces `linux-x64.zip` correctly
- [x] `mac_android_aot_engine` passed — `darwin-x64.zip` unaffected
- [x] `windows_android_aot_engine` passed — `windows-x64.zip` unaffected
- [x] `ci.yaml validation` passed — builder JSON and `.ci.yaml` entry
are structurally valid
- [x] Archive paths are unique across all builder configs (verified
locally)
- [x] Unit tests pass for `AndroidGenSnapshotArtifacts.getBinaryDirs()`
returning `linux-x64` entries on x64 hosts and `linux-arm64` entries on
arm64 hosts
- [x] Unit tests pass for `getArtifactPath` resolving `gen_snapshot` to
correct host-architecture path on both x64 and arm64 Linux

### Requires ARM64 Linux hardware (post-bringup)

The new `linux_arm64_android_aot_engine` builder is `bringup: true` and
does not run on PR checks. The `BUILD.gn` code path (`host_cpu ==
"arm64"`) is only exercised on ARM64 hosts. The following need to be
validated once the builder runs on ARM64 infrastructure:

- [ ] `gen_snapshot` compiles and links on ARM64 Linux
- [ ] CI builder produces `linux-arm64.zip` archives for all Android
target CPUs (arm, arm64, x64, riscv64) in both profile and release modes
- [ ] `analyze_snapshot` produces `analyze-snapshot-linux-arm64.zip` for
64-bit targets
- [ ] Artifacts download correctly on an ARM64 Linux host via `flutter
precache`

---------

Co-authored-by: Jackson Gardner <jacksongardner@google.com>

…s on linux-arm64 (flutter#186917)

flutter#182552 added support in the
Flutter tools for using a version of gen_snapshot that runs on
linux-arm64 hosts and targets Android devices.

However, the engine build infrastructure is not currently set up to
build this kind of gen_snapshot binary.

This PR contains changes needed to build engine artifacts on linux-arm64
machines. With this PR a linux-arm64 build environment can:
* run "gclient sync"
* build targets like zip_archives/android-arm64-profile/linux-arm64.zip
that were added in flutter#182552