[danielbolsson]

Motivation

The Windows build jobs fail while Meson configures the therock-amd-mesa sysdep,
because neither flex nor bison is present on the runner:

[therock-amd-mesa] Program win_flex found: NO
[therock-amd-mesa] Program flex lex found: NO
[therock-amd-mesa] .../amd-mesa/build/patch_source/meson.build:2206:17:
    ERROR: Program 'flex lex' not found or not executable
FAILED: third-party/sysdeps/windows/amd-mesa/build/stamp/build.stamp

Mesa's Meson build generates its lexer/parser sources at configure time, so without
those two programs it cannot produce them and the build stops before compiling
anything. Every Windows build job dies here, which blocks unrelated PRs from ever
reaching their Windows test stages.

Technical Details

Root cause is a gap in the Windows "Install requirements" step: it installs ccache,
ninja, strawberryperl, awscli and pkgconfiglite via Chocolatey, but not the
package providing flex/bison. This change adds winflexbison3 alongside them,
using the same --no-progress -y flags as the surrounding invocations.

winflexbison3 is the standard Windows port and installs both win_flex and
win_bison; Meson's flex lex lookup resolves against it. TheRock's own Windows
workflow already installs this package for the same reason, so this brings the
rocm-systems workflow in line rather than inventing a new approach.

Scope is deliberately limited to the CI workflow — no build sources, CMake, or
project code are touched.

Risk: low. A single added package install on the Windows CI image; it cannot affect
Linux jobs or any build output, and the worst case is an unused package.

Issue Tracking

JIRA ID: ROCM-30032

Test Plan

CI-driven, since the change only takes effect on the CI runner. Opening this as a
normal (non-draft) PR runs the full Windows build including gfx1151, which is the
job that currently fails at the mesa configure step.

Pass criteria: the Windows build proceeds past third-party/sysdeps/windows/amd-mesa
without the Program 'flex lex' not found error.

Test Result

Pending CI on this PR.

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/rocm-systems/blob/develop/CONTRIBUTING.md.

[therock-pr-bot]

✅ All Policy Checks Passed

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📝 PR Description	✅ Pass	—
⛔ Forbidden Files	✅ Pass	—
🧪 Unit Test	✅ Pass	PR does not contain code files — Unit Test auto-passed
🚫 Draft PR	🔜 To Be Enabled	—
🚩 Feature Flag	🔜 To Be Enabled	—
📊 Code Coverage	🔜 To Be Enabled	—

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[amd-justchen]

Will merge given approvals and goal to fix forward previously found build failures:

Hi! I created PR #10951 in rocm-systems to address build issue on Windows I saw multiple times during weekend (not flake). It adds missing winflexbison3 install requirement. Now after ~5 hours build I can see that the fix worked, but build failed later on another error: [255/322] Flatten split artifacts for fft to dist/rocm → FAILED

It seems it could be related to this particular runner https://github.com/ROCm/rocm-systems/actions/runs/33374472878/job/99433063145?pr=10951#step:10:79

 CPU:              AMD EPYC 7452 32-Core Processor                 (AMD64)
                          Logical cores: 96

        GPU:              GPU 0: 	None
        RAM:              Total Physical Memory: 383.99 GB
                          Avail Physical Memory: 368.29 GB
                          Avail Virtual  Memory: 408.54 GB

        STORAGE:          Disk Total Space: 419.45 GB
                          Disk Avail Space: 362.95 GB
                          Disk Used  Space: 56.5 GB
                          Disk Usage: 13.47 %

I reran to see that it builds successfully and no longer fails at flatten split artifacts for windows, and other tests are unrelated.

[systems-assistant]

TheRock Submodule Bump Activity

Newest first

• 2026-09-01 — Included in TheRock via ROCm/TheRock#7793.