v2025.3.0

Migrate from LLVM 16.0.6 to 20.1.8 and Halide 16.0.0 to 19.0.0

- Update llvm-prebuilt.yml: version matrix [18.1.8, 20.1.8] with release/20.x branch
- Update halide-prebuilt.yml: version matrix [18.0.0, 19.0.0] with dynamic LLVM mapping
- Create LLVM 20 patches (lld-install-targets, llvm-name-prefix)
- Create Halide 19 patches (host-tools-dir, disable-autoschedulers, verbose-warnings)
- Remove all LLVM 16 and Halide 16 patches (6 files deleted)
- Note: clang-ast-introspection patch no longer needed in LLVM 20
- Update documentation: version examples and patch version ranges

Use LLVM 18.1.8 for both Halide 18 and 19 builds

Both Halide versions support LLVM 18 (Halide 19 requires LLVM 17-20).
This simplifies the build matrix and avoids needing LLVM 20 for Halide.

Fix LLVM 20 build: clang-pseudo-gen target no longer exists

The clang-pseudo-gen target was removed in LLVM 20.
Only build it for LLVM 18.1.8, while clang-tidy-confusable-chars-gen
still exists in both versions.

Disable Halide autoschedulers via CMake option

Set -DWITH_AUTOSCHEDULERS=OFF to properly disable autoschedulers.
The patch only commented out the subdirectory but didn't disable the
feature, causing packaging errors for missing Halide_Adams2019 target.

Fix LLVM 20 cross-compilation by building required host tools

- Added llvm-as, llvm-link, llvm-nm, llvm-readobj, opt to host tools build for LLVM 20
- These tools use setup_host_tool() in LLVM 20 and must be available as host binaries
- Also added llvm-nm, llvm-readobj for LLVM 18 for consistency
- Fixes aarch64-ubuntu-22.04 build failure: 'file INSTALL cannot copy llvm-nm'

Fix Halide 19 host tools build by disabling autoschedulers

- Added -DWITH_AUTOSCHEDULERS=OFF to host tools configuration
- Previously only set for target build, causing host build to fail when patches disabled autoscheduler sources
- Fixes: 'install TARGETS given target Halide_Adams2019 which does not exist'

Fix Halide 19 macOS build by raising deployment target to 10.15

- Halide 19 uses std::filesystem which requires macOS 10.15+
- Set MACOSX_DEPLOYMENT_TARGET=10.15 for Halide 19, keep 10.13 for Halide 18
- Fixes: 'path' is unavailable: introduced in macOS 10.15

Fix LLVM 20 Ubuntu builds by freeing disk space after host tools

- Added cleanup step to remove .o, .a, and .cmake.d files from llvm-host build
- LLVM 20 builds consume more disk space than LLVM 18, causing 'No space left on device' errors
- Only runs on Linux runners where disk space is constrained
- Keeps binaries needed for cross-compilation

Aggressively free disk space by removing entire llvm-host build

- Previous cleanup only removed .o/.a files, not enough for aarch64-ubuntu-22.04
- Now: save host binaries, remove entire llvm-host directory, restore just bin/
- Frees maximum disk space before target build (gigabytes vs megabytes)
- Fixes: aarch64-ubuntu-22.04 'No space left on device' during Install LLVM

v2025.2.0

• Drop Ubuntu 20.04
• Add Ubuntu 24.04
• Drop LLVM 14

v2025.1.0

• Add cctools build for Ubuntu 24.04
• Add cctools build for arm64 (22.04, 24.04)
• Add clang+llvm 18.1.6 distribution
• Remove custom Rust distribution
• Add Halide 18 build

v2023.3.0

• Add clang-llvm 16.0.6, drop 12.0.1
• Add llvm-llc, llvm-lli, llvm-opt tools
• Add Halide 16.0.0, drop 14.0.0
• Update cctools to latest
• Add Rust 1.73, drop 1.64
• Remove Darling workflow

v2023.1.0

Fix arm64 clang+llvm and Halide builds

v2022.2.0

• Add Ubuntu 22.04, remove Ubuntu 18.04
• Add LLVM 14.0.6, refresh LLVM 12.0.1
• Add Halide 14.0.0, refresh Halide 12.0.1
• Add initial Rust 1.64 distribution (x86_64)
• Refresh cctools Linux distribution (lipo)
• Add Darling distribution (experimental)

2021.2.4

• Fix lld libraries cmake export
• Use Windows dynamic runtime

2021.2.3

• Add ubuntu-18.04 / ubuntu-20.04 builds
• Add missing lld development libraries

2021.2.2

• Fix lld library installation
• Add missing Halide targets

2021.2.1

Added aarch64 builds for Windows, macOS and Linux