hf_text-generation-inference/backends/llamacpp/csrc/ffi.hpp

106 lines
3.8 KiB
C++

//
// Created by mfuntowicz on 10/23/24.
//
#ifndef TGI_LLAMA_CPP_BACKEND_FFI_HPP
#define TGI_LLAMA_CPP_BACKEND_FFI_HPP
#include <exception>
#include <filesystem>
#include <string_view>
#include <spdlog/spdlog.h>
#include "backend.hpp"
namespace huggingface::tgi::backends::llamacpp {
struct generation_params_t;
struct sampling_params_t;
class llama_cpp_backend_impl_t;
}
#include "backends/llamacpp/src/lib.rs.h"
namespace huggingface::tgi::backends::llamacpp {
// Concept identifying types which have a .generate() -> size_t method to do in-place generation
template<typename T>
concept has_emplace_generate = requires(
T t,
std::span<const llama_token> input_tokens,
std::span<llama_token> generated_tokens,
const generation_params_t &generation_params,
const sampling_params_t &sampling_params,
llama_decode_callback callback
) {
{
t.generate(input_tokens, generated_tokens, generation_params, sampling_params, callback)
} -> std::same_as<std::expected<size_t, backend_error_t>>;
};
static_assert(has_emplace_generate<single_worker_backend_t>,
"single_worker_backend_t doesn't meet concept is_generate_emplace_capable");
static_assert(has_emplace_generate<multi_worker_backend_t>,
"multi_worker_backend_t doesn't meet concept is_generate_emplace_capable");
class llama_cpp_backend_exception_t : std::exception {
};
/**
* Llama.cpp backend interfacing with Rust FFI layer
*/
class llama_cpp_backend_impl_t {
private:
std::variant<single_worker_backend_t, multi_worker_backend_t> mInner_;
public:
explicit llama_cpp_backend_impl_t(single_worker_backend_t &&backend) : mInner_(std::move(backend)) {}
explicit llama_cpp_backend_impl_t(multi_worker_backend_t &&backend) : mInner_(std::move(backend)) {}
size_t generate(
rust::Slice<const uint32_t> input_tokens,
rust::Slice <uint32_t> generated_tokens,
const generation_params_t &generation_params,
const sampling_params_t &sampling_params,
rust::Fn<void(uint32_t, float_t, bool)> callback
) {
// Define the visitor lambda function which requires the has_emplace_generate constraint on T
static auto inner_fw = [=, &generation_params, &sampling_params]<has_emplace_generate T>(T &&backend)
-> std::expected<size_t, backend_error_t> {
// Ask the compiler to create view over Rust slice transmuting from uint32_t* to int32_t*
auto input_tokens_v =
std::span(reinterpret_cast<const llama_token *>(input_tokens.data()), input_tokens.size());
auto generated_tokens_v =
std::span(reinterpret_cast<llama_token *>(generated_tokens.data()), generated_tokens.size());
return backend.generate(
input_tokens_v, generated_tokens_v, generation_params, sampling_params, callback);
};
if (const auto result = std::visit(inner_fw, mInner_); result.has_value()) {
return *result;
} else {
throw llama_cpp_backend_exception_t();
}
}
};
std::unique_ptr<llama_cpp_backend_impl_t> create_single_worker_backend(rust::Str modelPath) {
const auto cxxPath = std::string(modelPath);
auto params = llama_model_default_params();
params.use_mmap = true;
auto *model = llama_load_model_from_file(cxxPath.c_str(), params);
auto backend = single_worker_backend_t(model, std::nullopt);
return std::make_unique<llama_cpp_backend_impl_t>(std::move(backend));
}
}
#endif //TGI_LLAMA_CPP_BACKEND_FFI_HPP