Bazel for RISC-V

Building Bazel from source for RISC-V architecture with automated CI/CD.

Purpose

Bazel is a build system required for building IntelliJ IDEA and other JetBrains IDEs from source. Official Bazel releases don't include RISC-V binaries, and Bazelisk (the version manager) doesn't support RISC-V architecture.

This repository:

• Documents the process of building Bazel from source on RISC-V
• Provides automated CI/CD for building Bazel releases
• Publishes RISC-V binary releases for the community

Current Status

⚠️ IMPORTANT LIMITATION (2025-11-26):

• Debian RISC-V repositories only provide JDK 21
• Bazel 6.5.0 is incompatible with JDK 21 (module access errors)
• Bazel 7.4.1 has JNI header sandboxing issues on RISC-V
• Building Bazel on RISC-V currently blocked until:
  • JDK 11 or 17 becomes available for RISC-V, OR
  • Bazel fixes RISC-V JDK 21 support

Community success: Bazel 6.5.0 successfully built on RISC-V in July 2024 (using JDK 11 or 17)

Our findings: Documented JDK compatibility issues and attempted fixes. See docs/versions.md and docs/troubleshooting.md for details.

Hardware

Primary build machine: Banana Pi F3 16GB

• CPU: SpacemiT K1 8-core RISC-V @ 2GHz
• RAM: 16GB LPDDR4 (exceeds 8GB requirement)
• OS: Debian RISC-V

GitHub Runner: Self-hosted at /mnt/c/support/users/dev/riscv/docker/docker-dev

Quick Start

Prerequisites

sudo apt update
sudo apt install build-essential openjdk-21-jdk zip unzip python3 git

Build Bazel 6.5.0 (Verified Working)

# Download distribution archive
wget https://github.com/bazelbuild/bazel/releases/download/6.5.0/bazel-6.5.0-dist.zip
unzip bazel-6.5.0-dist.zip -d bazel-6.5.0
cd bazel-6.5.0

# Bootstrap build (requires ~8GB RAM, ~30-60 min on 8-core)
env EXTRA_BAZEL_ARGS="--host_javabase=@local_jdk//:jdk" ./compile.sh

# Install
sudo cp output/bazel /usr/local/bin/
bazel --version

Problem: Bazelisk Doesn't Support RISC-V

Bazelisk is the official Bazel version manager that auto-downloads Bazel binaries.

What we tried:

git clone https://github.com/bazelbuild/bazelisk.git
cd bazelisk
go build
sudo mv bazelisk /usr/local/bin/bazel
bazel --version

Error:

2025/11/25 22:36:17 could not download Bazel: could not determine path segment
to use for Bazel binary: unsupported machine architecture "riscv64",
must be arm64 or x86_64

Why: Bazelisk only downloads pre-built binaries for arm64/x86_64. No RISC-V builds in official releases.

Solution: Build from Source

Tested Versions

Version	Status	Date Tested	Notes
6.5.0	✅ Works	2024-07	Community verified
7.4.1	⚠️ Untested	-	Latest release

Build Process

The build uses bootstrapping: Bazel builds itself using a minimal Java-based build system.

Build steps:

1. Download -dist.zip archive (contains all sources)
2. Run compile.sh (bootstrap build script)
3. Output binary created in output/bazel
4. Install to /usr/local/bin/

Requirements:

• JDK 21 (we use Eclipse Temurin)
• ~8GB RAM minimum (F3 has 16GB)
• ~2GB disk space
• Build tools: gcc, g++, zip, unzip, python3

Build time: 30-60 minutes on Banana Pi F3 (8-core)

CI/CD Plan

GitHub Actions Workflow

Using our self-hosted RISC-V runner:

name: Build Bazel

on:
  workflow_dispatch:
    inputs:
      bazel_version:
        description: 'Bazel version to build'
        required: true
        default: '6.5.0'

jobs:
  build:
    runs-on: [self-hosted, riscv64]

    steps:
      - name: Install dependencies
        run: |
          sudo apt update
          sudo apt install -y build-essential openjdk-21-jdk zip unzip python3

      - name: Download Bazel source
        run: |
          wget https://github.com/bazelbuild/bazel/releases/download/${{ inputs.bazel_version }}/bazel-${{ inputs.bazel_version }}-dist.zip
          unzip bazel-${{ inputs.bazel_version }}-dist.zip -d bazel-build

      - name: Build Bazel
        run: |
          cd bazel-build
          env EXTRA_BAZEL_ARGS="--host_javabase=@local_jdk//:jdk" ./compile.sh

      - name: Create release artifact
        run: |
          cd bazel-build
          tar czf bazel-${{ inputs.bazel_version }}-linux-riscv64.tar.gz -C output bazel

      - name: Upload artifact
        uses: actions/upload-artifact@v4
        with:
          name: bazel-${{ inputs.bazel_version }}-linux-riscv64
          path: bazel-build/bazel-${{ inputs.bazel_version }}-linux-riscv64.tar.gz

      - name: Create GitHub Release
        uses: softprops/action-gh-release@v1
        with:
          tag_name: v${{ inputs.bazel_version }}
          files: bazel-build/bazel-${{ inputs.bazel_version }}-linux-riscv64.tar.gz

Release Strategy

1. Manual trigger via workflow_dispatch (choose version)
2. Build on self-hosted RISC-V runner (Banana Pi F3)
3. Create release with binary artifact
4. Tag format: v{version} (e.g., v6.5.0)

Automated Testing

- name: Test Bazel binary
  run: |
    cd bazel-build
    ./output/bazel --version
    ./output/bazel version

Directory Structure

bazel-riscv/
├── .github/
│   └── workflows/
│       ├── build-bazel.yml          # Main build workflow
│       └── test-bazel.yml           # Test workflow
├── docs/
│   ├── build-process.md             # Detailed build documentation
│   ├── troubleshooting.md           # Common issues
│   └── versions.md                  # Tested version matrix
├── scripts/
│   ├── build.sh                     # Build script
│   ├── install.sh                   # Installation script
│   └── test.sh                      # Test script
├── patches/                         # RISC-V specific patches (if needed)
├── README.md
└── LICENSE

Use Cases

For JetBrains IDE Development

This Bazel build is required for:

• Building IntelliJ IDEA from source on RISC-V
• Building PyCharm, WebStorm, etc.
• JetBrains IDE development on RISC-V hardware

See related project: IntelliJ IDEA RISC-V Build

For General RISC-V Development

Bazel is used by many projects:

• TensorFlow
• Envoy
• gRPC
• Kubernetes
• Many Google projects

Resources

Official Bazel:

• Bazel releases
• Build from source docs
• RISC-V support issue

Community:

• Community 6.5.0 build - July 2024 success story

Related:

• JetBrains-IDE-Multiarch - Uses Bazel for IDE builds
• docker-for-riscv64 - Our GitHub runner setup

Contributing

Contributions welcome! Areas of interest:

• Testing newer Bazel versions (7.x)
• Optimizing build performance
• Creating patches for RISC-V specific issues
• Improving CI/CD workflows

License

This repository contains build scripts and documentation. Bazel itself is licensed under Apache 2.0.

Maintainer

Built and maintained for RISC-V development on Banana Pi F3.

Related project: Building JetBrains IDEs on RISC-V architecture