This devcontainer provides a full WAMR development environment. The image is built from Dockerfile (multi-stage) using the repo root as the build context (.devcontainer/devcontainer.json sets "context": "..").

The image ships a prebuilt LLVM (LLVM 18.1.8, the same llvmorg-18.1.8 tag used by CI) at /opt/llvm:

• It is compiled once at image build time by the repo's own build-scripts/build_llvm.py in the llvm-builder stage (Dockerfile). Only the repackaged install tree (bin/include/lib/libexec/share, about 1.5-2 GB) is copied into the final image; the source clone, build tree and CPack tarball are removed as intermediate outputs.
• At container creation, .devcontainer/setup_llvm.sh (run via postCreateCommand) symlinks core/deps/llvm/build -> /opt/llvm in the workspace. That is the exact location WAMR's cmake requires, so wamrc (AOT) and -DWAMR_BUILD_JIT=1 (LLVM JIT) builds work with zero extra cmake flags. core/deps/** is git-ignored, so the symlink never pollutes git status.

The LLVM_ARCH build argument (default X86) controls which LLVM targets are compiled. Override it in .devcontainer/devcontainer.json:

"args": {
  "LLVM_ARCH": "AArch64 ARM Mips RISCV X86"   // longer image build time
}

Notes:

• On a non-x86_64 host (e.g. Apple Silicon), the container is arm64; the default X86 backend still cross-compiles X86 AOT, but for native AOT set LLVM_ARCH=AArch64 (or ARM, ...).
• Rebuilding the image is fast when only unrelated final-stage layers change: the llvm-builder stage is reused from the layer cache. An LLVM upgrade means changing the version/tag in build-scripts/build_llvm.py, which automatically invalidates the builder stage on the next image build - no --no-cache needed.

To build your own LLVM (e.g. different targets) inside the container instead:

rm core/deps/llvm/build            # remove the symlink
cd wamr-compiler && ./build_llvm.sh --arch "AArch64 ARM Mips RISCV X86"

This clones llvm-project into the workspace core/deps/llvm and builds there (30-60 min), replacing the image-provided libraries for this workspace.