Draft: Opensource Hexagon toolchain and CI/CD

William Nguyenrequested to merge
willng/eigen:hexagon_toolchain into master

Eigen MR: Hexagon DSP CI/CD and Open Source Toolchain Integration

Reference issue

This MR is part of the breakdown of !1695: !1695

What does this implement/fix?

This Merge Request is the first in a series breaking down !1695, focusing on integrating the open source Hexagon toolchain and enabling CI/CD for Hexagon DSP cross-compilation and testing.

Summary of Changes

  • CI Modernization

    • Adds a new ci/Dockerfile to build a CI image with the open source Hexagon toolchain (20.1.4) and all dependencies pre-installed.
    • Updates .gitlab-ci.yml to use new Hexagon-specific build and test pipelines (build.hexagon.gitlab-ci.yml, test.hexagon.gitlab-ci.yml), disabling legacy Linux/Windows jobs for this MR.
    • CI jobs now use pre-built Docker images for consistent, reproducible environments.

  • CMake Toolchain

    • Introduces cmake/HexagonToolchain.cmake for robust Hexagon cross-compilation, with auto-detection of toolchain paths, sysroot, and architecture.
    • Ensures all compiler, linker, and sysroot settings are sourced from the open source toolchain.

  • Validation and Documentation

    • Adds ci/test-hexagon-setup.sh for automated validation of the Hexagon toolchain and QEMU emulator in CI and locally.
    • Provides ci/docs/hexagon-ci-guide.md with detailed instructions for local and CI usage, troubleshooting, and migration from legacy scripts.

  • Test and Build Matrix

    • Defines a comprehensive CI matrix for Hexagon v68/v73, HVX, debug, optimized, and minimal builds, with QEMU-based test execution and artifact collection.
    • Enables parallel and performance testing, with clear job separation and artifact retention.

  • Minor Source Fix

    • Updates test/main.h to include <hexagon_types.h> when building with HVX to avoid macro conflicts.

Additional information

This MR establishes a robust, open, and maintainable foundation for Hexagon DSP support in Eigen, using only open source toolchains and infrastructure. It enables reliable cross-compilation and QEMU-based testing in both CI and local environments, paving the way for further Hexagon vectorization and optimization work.

No core Eigen code is changed in this MR; all changes are CI, toolchain, and infrastructure related.

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