feat: support safetensors export in convert mode (#1444)

README.md

@@ -77,9 +77,10 @@ API and command-line option may change frequently.***
   - OpenCL
   - SYCL
 - Supported weight formats
-  - Pytorch checkpoint (`.ckpt` or `.pth`)
+  - Pytorch checkpoint (`.ckpt` or `.pth` or `.pt`)
   - Safetensors (`.safetensors`)
   - GGUF (`.gguf`)
+- Convert mode supports converting model weights to `.gguf` or `.safetensors`
 - Supported platforms
     - Linux
     - Mac OS

examples/cli/README.md

@@ -14,6 +14,9 @@ CLI Options:
   --metadata-format <string>  metadata output format, one of [text, json] (default: text)
   --canny                     apply canny preprocessor (edge detection)
   --convert-name              convert tensor name (for convert mode)
+                              convert mode writes `.gguf` or `.safetensors` based on the output extension.
+                              `.safetensors` export currently supports f16, bf16, f32, and i32 tensor types only.
+                              i32 is passthrough only; no f32 <-> i32 conversion is performed
   -v, --verbose               print extra info
   --color                     colors the logging tags according to level
   --taesd-preview-only        prevents usage of taesd for decoding the final image. (for use with --preview tae)

src/convert.cpp

@@ -0,0 +1,138 @@
+#include <cstring>
+#include <mutex>
+#include <regex>
+#include <vector>
+
+#include "model.h"
+#include "model_io/gguf_io.h"
+#include "model_io/safetensors_io.h"
+#include "util.h"
+
+#include "ggml-cpu.h"
+
+static ggml_type get_export_tensor_type(ModelLoader& model_loader,
+                                        const TensorStorage& tensor_storage,
+                                        ggml_type type,
+                                        const TensorTypeRules& tensor_type_rules) {
+    const std::string& name = tensor_storage.name;
+    ggml_type tensor_type   = tensor_storage.type;
+    ggml_type dst_type      = type;
+
+    for (const auto& tensor_type_rule : tensor_type_rules) {
+        std::regex pattern(tensor_type_rule.first);
+        if (std::regex_search(name, pattern)) {
+            dst_type = tensor_type_rule.second;
+            break;
+        }
+    }
+
+    if (model_loader.tensor_should_be_converted(tensor_storage, dst_type)) {
+        tensor_type = dst_type;
+    }
+
+    return tensor_type;
+}
+
+static bool load_tensors_for_export(ModelLoader& model_loader,
+                                    ggml_context* ggml_ctx,
+                                    ggml_type type,
+                                    const TensorTypeRules& tensor_type_rules,
+                                    std::vector<TensorWriteInfo>& tensors) {
+    std::mutex tensor_mutex;
+    auto on_new_tensor_cb = [&](const TensorStorage& tensor_storage, ggml_tensor** dst_tensor) -> bool {
+        const std::string& name = tensor_storage.name;
+        ggml_type tensor_type   = get_export_tensor_type(model_loader, tensor_storage, type, tensor_type_rules);
+
+        std::lock_guard<std::mutex> lock(tensor_mutex);
+        ggml_tensor* tensor = ggml_new_tensor(ggml_ctx, tensor_type, tensor_storage.n_dims, tensor_storage.ne);
+        if (tensor == nullptr) {
+            LOG_ERROR("ggml_new_tensor failed");
+            return false;
+        }
+        ggml_set_name(tensor, name.c_str());
+
+        if (!tensor->data) {
+            GGML_ASSERT(ggml_nelements(tensor) == 0);
+            // Avoid crashing writers by setting a dummy pointer for zero-sized tensors.
+            LOG_DEBUG("setting dummy pointer for zero-sized tensor %s", name.c_str());
+            tensor->data = ggml_get_mem_buffer(ggml_ctx);
+        }
+
+        TensorWriteInfo write_info;
+        write_info.tensor = tensor;
+        write_info.n_dims = tensor_storage.n_dims;
+        for (int i = 0; i < tensor_storage.n_dims; ++i) {
+            write_info.ne[i] = tensor_storage.ne[i];
+        }
+
+        *dst_tensor = tensor;
+        tensors.push_back(std::move(write_info));
+
+        return true;
+    };
+
+    bool success = model_loader.load_tensors(on_new_tensor_cb);
+    LOG_INFO("load tensors done");
+    return success;
+}
+
+bool convert(const char* input_path,
+             const char* vae_path,
+             const char* output_path,
+             sd_type_t output_type,
+             const char* tensor_type_rules,
+             bool convert_name) {
+    ModelLoader model_loader;
+
+    if (!model_loader.init_from_file(input_path)) {
+        LOG_ERROR("init model loader from file failed: '%s'", input_path);
+        return false;
+    }
+
+    if (vae_path != nullptr && strlen(vae_path) > 0) {
+        if (!model_loader.init_from_file(vae_path, "vae.")) {
+            LOG_ERROR("init model loader from file failed: '%s'", vae_path);
+            return false;
+        }
+    }
+    if (convert_name) {
+        model_loader.convert_tensors_name();
+    }
+
+    ggml_type type             = (ggml_type)output_type;
+    bool output_is_safetensors = ends_with(output_path, ".safetensors");
+    TensorTypeRules type_rules = parse_tensor_type_rules(tensor_type_rules);
+
+    auto backend    = ggml_backend_cpu_init();
+    size_t mem_size = 1 * 1024 * 1024;  // for padding
+    mem_size += model_loader.get_tensor_storage_map().size() * ggml_tensor_overhead();
+    mem_size += model_loader.get_params_mem_size(backend, type);
+    LOG_INFO("model tensors mem size: %.2fMB", mem_size / 1024.f / 1024.f);
+    ggml_context* ggml_ctx = ggml_init({mem_size, nullptr, false});
+
+    if (ggml_ctx == nullptr) {
+        LOG_ERROR("ggml_init failed for converter");
+        ggml_backend_free(backend);
+        return false;
+    }
+
+    std::vector<TensorWriteInfo> tensors;
+    bool success = load_tensors_for_export(model_loader, ggml_ctx, type, type_rules, tensors);
+    ggml_backend_free(backend);
+
+    std::string error;
+    if (success) {
+        if (output_is_safetensors) {
+            success = write_safetensors_file(output_path, tensors, &error);
+        } else {
+            success = write_gguf_file(output_path, tensors, &error);
+        }
+    }
+
+    if (!success && !error.empty()) {
+        LOG_ERROR("%s", error.c_str());
+    }
+
+    ggml_free(ggml_ctx);
+    return success;
+}

src/model.cpp

@@ -81,7 +81,7 @@ const char* unused_tensors[] = {
     "first_stage_model.bn.",
 };
 
-bool is_unused_tensor(std::string name) {
+bool is_unused_tensor(const std::string& name) {
     for (size_t i = 0; i < sizeof(unused_tensors) / sizeof(const char*); i++) {
         if (starts_with(name, unused_tensors[i])) {
             return true;
@@ -687,8 +687,8 @@ std::map<ggml_type, uint32_t> ModelLoader::get_vae_wtype_stat() {
     return wtype_stat;
 }
 
-static std::vector<std::pair<std::string, ggml_type>> parse_tensor_type_rules(const std::string& tensor_type_rules) {
+TensorTypeRules parse_tensor_type_rules(const std::string& tensor_type_rules) {
-    std::vector<std::pair<std::string, ggml_type>> result;
+    TensorTypeRules result;
     for (const auto& item : split_string(tensor_type_rules, ',')) {
         if (item.size() == 0)
             continue;
@@ -1121,91 +1121,6 @@ bool ModelLoader::tensor_should_be_converted(const TensorStorage& tensor_storage
     return false;
 }
 
-bool ModelLoader::save_to_gguf_file(const std::string& file_path, ggml_type type, const std::string& tensor_type_rules_str) {
-    auto tensor_type_rules = parse_tensor_type_rules(tensor_type_rules_str);
-    auto get_tensor_type   = [&](const TensorStorage& tensor_storage) -> ggml_type {
-        const std::string& name = tensor_storage.name;
-        ggml_type tensor_type   = tensor_storage.type;
-        ggml_type dst_type      = type;
-
-        for (const auto& tensor_type_rule : tensor_type_rules) {
-            std::regex pattern(tensor_type_rule.first);
-            if (std::regex_search(name, pattern)) {
-                dst_type = tensor_type_rule.second;
-                break;
-            }
-        }
-
-        if (tensor_should_be_converted(tensor_storage, dst_type)) {
-            tensor_type = dst_type;
-        }
-
-        return tensor_type;
-    };
-
-    auto backend    = ggml_backend_cpu_init();
-    size_t mem_size = 1 * 1024 * 1024;  // for padding
-    mem_size += tensor_storage_map.size() * ggml_tensor_overhead();
-    mem_size += get_params_mem_size(backend, type);
-    LOG_INFO("model tensors mem size: %.2fMB", mem_size / 1024.f / 1024.f);
-    ggml_context* ggml_ctx = ggml_init({mem_size, nullptr, false});
-
-    if (ggml_ctx == nullptr) {
-        LOG_ERROR("ggml_init failed for GGUF writer");
-        ggml_backend_free(backend);
-        return false;
-    }
-
-    std::vector<ggml_tensor*> tensors;
-    std::mutex tensor_mutex;
-    auto on_new_tensor_cb = [&](const TensorStorage& tensor_storage, ggml_tensor** dst_tensor) -> bool {
-        const std::string& name = tensor_storage.name;
-        ggml_type tensor_type   = get_tensor_type(tensor_storage);
-
-        std::lock_guard<std::mutex> lock(tensor_mutex);
-        ggml_tensor* tensor = ggml_new_tensor(ggml_ctx, tensor_type, tensor_storage.n_dims, tensor_storage.ne);
-        if (tensor == nullptr) {
-            LOG_ERROR("ggml_new_tensor failed");
-            return false;
-        }
-        ggml_set_name(tensor, name.c_str());
-
-        // LOG_DEBUG("%s %d %s %d[%d %d %d %d] %d[%d %d %d %d]", name.c_str(),
-        // ggml_nbytes(tensor), ggml_type_name(tensor_type),
-        // tensor_storage.n_dims,
-        // tensor_storage.ne[0], tensor_storage.ne[1], tensor_storage.ne[2], tensor_storage.ne[3],
-        // tensor->n_dims, tensor->ne[0], tensor->ne[1], tensor->ne[2], tensor->ne[3]);
-
-        if (!tensor->data) {
-            GGML_ASSERT(ggml_nelements(tensor) == 0);
-            // avoid crashing the gguf writer by setting a dummy pointer for zero-sized tensors
-            LOG_DEBUG("setting dummy pointer for zero-sized tensor %s", name.c_str());
-            tensor->data = ggml_get_mem_buffer(ggml_ctx);
-        }
-
-        *dst_tensor = tensor;
-        tensors.push_back(tensor);
-
-        return true;
-    };
-
-    bool success = load_tensors(on_new_tensor_cb);
-    ggml_backend_free(backend);
-    LOG_INFO("load tensors done");
-
-    std::string error;
-    if (success) {
-        success = write_gguf_file(file_path, tensors, &error);
-    }
-
-    if (!success && !error.empty()) {
-        LOG_ERROR("%s", error.c_str());
-    }
-
-    ggml_free(ggml_ctx);
-    return success;
-}
-
 int64_t ModelLoader::get_params_mem_size(ggml_backend_t backend, ggml_type type) {
     size_t alignment = 128;
     if (backend != nullptr) {
@@ -1225,28 +1140,3 @@ int64_t ModelLoader::get_params_mem_size(ggml_backend_t backend, ggml_type type)
 
     return mem_size;
 }
-
-bool convert(const char* input_path,
-             const char* vae_path,
-             const char* output_path,
-             sd_type_t output_type,
-             const char* tensor_type_rules,
-             bool convert_name) {
-    ModelLoader model_loader;
-
-    if (!model_loader.init_from_file(input_path)) {
-        LOG_ERROR("init model loader from file failed: '%s'", input_path);
-        return false;
-    }
-
-    if (vae_path != nullptr && strlen(vae_path) > 0) {
-        if (!model_loader.init_from_file(vae_path, "vae.")) {
-            LOG_ERROR("init model loader from file failed: '%s'", vae_path);
-            return false;
-        }
-    }
-    if (convert_name) {
-        model_loader.convert_tensors_name();
-    }
-    return model_loader.save_to_gguf_file(output_path, (ggml_type)output_type, tensor_type_rules);
-}

src/model.h

@@ -189,6 +189,9 @@ enum PMVersion {
 };
 
 typedef OrderedMap<std::string, TensorStorage> String2TensorStorage;
+using TensorTypeRules = std::vector<std::pair<std::string, ggml_type>>;
+
+TensorTypeRules parse_tensor_type_rules(const std::string& tensor_type_rules);
 
 class ModelLoader {
 protected:
@@ -231,7 +234,6 @@ public:
         return names;
     }
 
-    bool save_to_gguf_file(const std::string& file_path, ggml_type type, const std::string& tensor_type_rules);
     bool tensor_should_be_converted(const TensorStorage& tensor_storage, ggml_type type);
     int64_t get_params_mem_size(ggml_backend_t backend, ggml_type type = GGML_TYPE_COUNT);
     ~ModelLoader() = default;

src/model_io/gguf_io.cpp

@@ -95,7 +95,7 @@ bool read_gguf_file(const std::string& file_path,
 }
 
 bool write_gguf_file(const std::string& file_path,
-                     const std::vector<ggml_tensor*>& tensors,
+                     const std::vector<TensorWriteInfo>& tensors,
                      std::string* error) {
     gguf_context* gguf_ctx = gguf_init_empty();
     if (gguf_ctx == nullptr) {
@@ -103,7 +103,8 @@ bool write_gguf_file(const std::string& file_path,
         return false;
     }
 
-    for (ggml_tensor* tensor : tensors) {
+    for (const TensorWriteInfo& write_tensor : tensors) {
+        ggml_tensor* tensor = write_tensor.tensor;
         if (tensor == nullptr) {
             set_error(error, "null tensor cannot be written to GGUF");
             gguf_free(gguf_ctx);

src/model_io/gguf_io.h

@@ -11,7 +11,7 @@ bool read_gguf_file(const std::string& file_path,
                     std::vector<TensorStorage>& tensor_storages,
                     std::string* error = nullptr);
 bool write_gguf_file(const std::string& file_path,
-                     const std::vector<ggml_tensor*>& tensors,
+                     const std::vector<TensorWriteInfo>& tensors,
                      std::string* error = nullptr);
 
 #endif  // __SD_MODEL_IO_GGUF_IO_H__

src/model_io/safetensors_io.cpp

@@ -8,6 +8,7 @@
 
 #include "binary_io.h"
 #include "json.hpp"
+#include "util.h"
 
 static constexpr size_t ST_HEADER_SIZE_LEN = 8;
 
@@ -60,7 +61,7 @@ bool is_safetensors_file(const std::string& file_path) {
     return true;
 }
 
-static ggml_type str_to_ggml_type(const std::string& dtype) {
+static ggml_type safetensors_dtype_to_ggml_type(const std::string& dtype) {
     ggml_type ttype = GGML_TYPE_COUNT;
     if (dtype == "F16") {
         ttype = GGML_TYPE_F16;
@@ -154,7 +155,7 @@ bool read_safetensors_file(const std::string& file_path,
         size_t begin = tensor_info["data_offsets"][0].get<size_t>();
         size_t end   = tensor_info["data_offsets"][1].get<size_t>();
 
-        ggml_type type = str_to_ggml_type(dtype);
+        ggml_type type = safetensors_dtype_to_ggml_type(dtype);
         if (type == GGML_TYPE_COUNT) {
             set_error(error, "unsupported dtype '" + dtype + "' (tensor '" + name + "')");
             return false;
@@ -221,3 +222,95 @@ bool read_safetensors_file(const std::string& file_path,
 
     return true;
 }
+
+static bool ggml_type_to_safetensors_dtype(ggml_type type, std::string* dtype) {
+    switch (type) {
+        case GGML_TYPE_F16:
+            *dtype = "F16";
+            return true;
+        case GGML_TYPE_BF16:
+            *dtype = "BF16";
+            return true;
+        case GGML_TYPE_F32:
+            *dtype = "F32";
+            return true;
+        case GGML_TYPE_I32:
+            *dtype = "I32";
+            return true;
+        default:
+            return false;
+    }
+}
+
+bool write_safetensors_file(const std::string& file_path,
+                            const std::vector<TensorWriteInfo>& tensors,
+                            std::string* error) {
+    nlohmann::ordered_json header = nlohmann::ordered_json::object();
+
+    uint64_t data_offset = 0;
+    for (const TensorWriteInfo& write_tensor : tensors) {
+        ggml_tensor* tensor = write_tensor.tensor;
+        if (tensor == nullptr) {
+            set_error(error, "null tensor cannot be written to safetensors");
+            return false;
+        }
+
+        const std::string name = ggml_get_name(tensor);
+        std::string dtype;
+        if (!ggml_type_to_safetensors_dtype(tensor->type, &dtype)) {
+            set_error(error,
+                      "unsupported safetensors dtype '" + std::string(ggml_type_name(tensor->type)) +
+                          "' for tensor '" + name + "'");
+            return false;
+        }
+
+        const uint64_t tensor_nbytes = ggml_nbytes(tensor);
+
+        nlohmann::ordered_json json_tensor_info = nlohmann::ordered_json::object();
+        json_tensor_info["dtype"]               = dtype;
+
+        nlohmann::ordered_json shape = nlohmann::ordered_json::array();
+        for (int i = 0; i < write_tensor.n_dims; ++i) {
+            shape.push_back(write_tensor.ne[write_tensor.n_dims - 1 - i]);
+        }
+        json_tensor_info["shape"] = shape;
+
+        nlohmann::ordered_json data_offsets = nlohmann::ordered_json::array();
+        data_offsets.push_back(data_offset);
+        data_offsets.push_back(data_offset + tensor_nbytes);
+        json_tensor_info["data_offsets"] = data_offsets;
+
+        header[name] = json_tensor_info;
+        data_offset += tensor_nbytes;
+    }
+
+    const std::string header_str = header.dump();
+
+    std::ofstream file(file_path, std::ios::binary);
+    if (!file.is_open()) {
+        set_error(error, "failed to open '" + file_path + "' for writing");
+        return false;
+    }
+
+    LOG_INFO("trying to save tensors to %s", file_path.c_str());
+    model_io::write_u64(file, header_str.size());
+    file.write(header_str.data(), header_str.size());
+    if (!file) {
+        set_error(error, "failed to write safetensors header to '" + file_path + "'");
+        return false;
+    }
+
+    for (const TensorWriteInfo& write_tensor : tensors) {
+        ggml_tensor* tensor        = write_tensor.tensor;
+        const std::string name     = ggml_get_name(tensor);
+        const size_t tensor_nbytes = ggml_nbytes(tensor);
+        file.write((const char*)tensor->data, tensor_nbytes);
+        if (!file) {
+            set_error(error,
+                      "failed to write tensor '" + name + "' to '" + file_path + "'");
+            return false;
+        }
+    }
+
+    return true;
+}

src/model_io/safetensors_io.h

@@ -10,5 +10,8 @@ bool is_safetensors_file(const std::string& file_path);
 bool read_safetensors_file(const std::string& file_path,
                            std::vector<TensorStorage>& tensor_storages,
                            std::string* error = nullptr);
+bool write_safetensors_file(const std::string& file_path,
+                            const std::vector<TensorWriteInfo>& tensors,
+                            std::string* error = nullptr);
 
 #endif  // __SD_MODEL_IO_SAFETENSORS_IO_H__

src/model_io/tensor_storage.h

@@ -121,6 +121,12 @@ struct TensorStorage {
     }
 };
 
+struct TensorWriteInfo {
+    int64_t ne[SD_MAX_DIMS] = {1, 1, 1, 1, 1};
+    int n_dims              = 0;
+    ggml_tensor* tensor     = nullptr;
+};
+
 typedef std::function<bool(const TensorStorage&, ggml_tensor**)> on_new_tensor_cb_t;
 
 #endif  // __SD_TENSOR_STORAGE_H__