# Updating the vendored llama.cpp
erllama vendors a pinned copy of llama.cpp under `c_src/llama.cpp/`.
The current pin is **b9093**.
This file documents the bump procedure.
## Why pin
- Reproducible builds: every developer and CI run compiles the same
source.
- Hex.pm-friendly: published packages contain the full source so no
network access is needed at install time.
- Backend stability: llama.cpp moves fast, especially in the model
zoo. We control when we adopt new architectures.
## What we ship
We vendor only the parts we need. Currently:
```
c_src/llama.cpp/
CMakeLists.txt llama.cpp's top-level CMake
LICENSE MIT (dual MIT/Apache, llama.cpp pick MIT)
cmake/ CMake helpers (toolchain files, etc)
include/ public headers (llama.h, etc)
src/ llama core (model.cpp, context.cpp, etc)
ggml/
CMakeLists.txt
cmake/ ggml CMake helpers (common.cmake, GitVars.cmake)
include/ public ggml headers
src/
CMakeLists.txt
ggml*.c, ggml*.cpp, ggml*.h core ggml + frontends
gguf.cpp GGUF file format
ggml-cpu/ CPU SIMD kernels (mandatory)
ggml-metal/ Apple GPU backend (Apple Silicon)
ggml-cuda/ NVIDIA GPU backend (Linux x86-64)
ggml-blas/ BLAS backend (OpenBLAS / Accelerate)
```
Excluded (unused or out-of-scope for v1):
- `tools/`, `examples/`, `tests/`, `docs/`, `models/`, `gguf-py/`,
`benches/`, `ci/`, `scripts/`, `grammars/`, `vendor/`, `.git/`,
`.github/`, `AUTHORS`, `.devops/`
- ggml backends we do not link: Vulkan, SYCL, OpenCL, CANN, Hexagon,
HIP, MUSA, RPC, ZDNN, ZenDNN, Virtgpu, Webgpu, OpenVINO
If a user needs one of the excluded backends they can build erllama
against an unvendored llama.cpp via `git+` rebar dep instead of the
hex package; that path is supported but unsupported in this scaffold.
## Bumping
Pick a tag from <https://github.com/ggml-org/llama.cpp/tags>. Newer
tags are usually fine; check the changelog for breaking C-API changes
to `llama_state_seq_*` (the cache layer depends on those).
```sh
# 1. Clone the new tag into a scratch directory.
cd /tmp
git clone --depth=1 --branch=<TAG> https://github.com/ggml-org/llama.cpp llama.cpp.new
# 2. Sync the parts we vendor.
cd /Users/benoitc/Projects/erllama
rm -rf c_src/llama.cpp
mkdir -p c_src/llama.cpp/ggml/src
cp -r /tmp/llama.cpp.new/{src,include,cmake,CMakeLists.txt,LICENSE} \
c_src/llama.cpp/
cp -r /tmp/llama.cpp.new/ggml/{include,cmake,CMakeLists.txt} \
c_src/llama.cpp/ggml/
cp /tmp/llama.cpp.new/ggml/src/CMakeLists.txt \
c_src/llama.cpp/ggml/src/
cp /tmp/llama.cpp.new/ggml/src/ggml*.c \
/tmp/llama.cpp.new/ggml/src/ggml*.cpp \
/tmp/llama.cpp.new/ggml/src/ggml*.h \
/tmp/llama.cpp.new/ggml/src/gguf.cpp \
c_src/llama.cpp/ggml/src/
cp -r /tmp/llama.cpp.new/ggml/src/{ggml-cpu,ggml-metal,ggml-cuda,ggml-blas} \
c_src/llama.cpp/ggml/src/
# 3. Rebuild and run the full test gauntlet.
rm -rf _build
rebar3 compile
rebar3 fmt --check && rebar3 lint && rebar3 xref \
&& rebar3 eunit && rebar3 proper && rebar3 ct
# 4. Update the pin reference in this file and in
# c_src/llama.cpp/.version (if present).
# 5. Commit with a message naming the new tag.
```
## Configuration knobs
The CMake configure step honours these env vars (passed via
`ERLLAMA_OPTS` to `do_cmake.sh`):
```
ERLLAMA_OPTS="-DGGML_CUDA=ON" # enable CUDA on Linux x86-64
ERLLAMA_OPTS="-DGGML_METAL=OFF" # disable Metal on Darwin
ERLLAMA_OPTS="-DGGML_BLAS=OFF" # disable BLAS
ERLLAMA_OPTS="-DCMAKE_BUILD_TYPE=Debug" # debug build
```
The build step honours `ERLLAMA_BUILDOPTS` (passed to `cmake --build`).
## Why we drop `common/`
llama.cpp's `common/` carries HTTP / Hugging Face download helpers
that pull in cpp-httplib (5 MB). erllama uses the public `llama.h` API
directly and provides its own thin sampling / tokenization helpers in
the NIF; nothing in `common/` is on our critical path.
