Update GGML to b6646 (#12245)

Notable EOLs with this change:
- MacOS v12 and v13 are no longer supported (v14+ required)
- AMD gfx900 and gfx906 are no longer supported

ml/backend/ggml/ggml/src/gguf.cpp

@@ -273,7 +273,7 @@ struct gguf_reader {
     }
 
     bool read(std::string & dst) const {
-        uint64_t size = -1;
+        uint64_t size = 0;
         if (!read(size)) {
             return false;
         }
@@ -523,7 +523,7 @@ struct gguf_context * gguf_init_from_file_impl(FILE * file, struct gguf_init_par
 
         // tensor shape
         {
-            uint32_t n_dims = -1;
+            uint32_t n_dims = 0;
             ok = ok && gr.read(n_dims);
             if (n_dims > GGML_MAX_DIMS) {
                 GGML_LOG_ERROR("%s: tensor '%s' has invalid number of dimensions: %" PRIu32 " > %" PRIu32 "\n",
@@ -1169,50 +1169,51 @@ void gguf_set_tensor_data(struct gguf_context * ctx, const char * name, const vo
     ctx->info[tensor_id].t.data = (void *)(uintptr_t)data; // double cast suppresses warning about casting away const
 }
 
-struct gguf_writer {
-    std::vector<int8_t> & buf;
+struct gguf_writer_base {
+    size_t written_bytes {0u};
+
+    ~gguf_writer_base(void) {}
 
-    gguf_writer(std::vector<int8_t> & buf) : buf(buf) {}
+    // we bet on devirtualization
+    virtual void write(int8_t val) = 0;
+    virtual void write(const std::vector<int8_t> & val) = 0;
+    virtual void write_tensor_data(const struct gguf_tensor_info & info, size_t offset_data, size_t alignment) = 0;
 
     template <typename T>
-    void write(const T & val) const {
+    void write(const T & val) {
         for (size_t i = 0; i < sizeof(val); ++i) {
-            buf.push_back(reinterpret_cast<const int8_t *>(&val)[i]);
+            write(reinterpret_cast<const int8_t *>(&val)[i]);
         }
     }
 
-    void write(const std::vector<int8_t> & val) const {
-        buf.insert(buf.end(), val.begin(), val.end());
-    }
-
-    void write(const bool & val) const {
+    void write(const bool & val) {
         const int8_t val8 = val ? 1 : 0;
         write(val8);
     }
 
-    void write(const std::string & val) const {
+    void write(const std::string & val) {
         {
             const uint64_t n = val.length();
             write(n);
         }
         for (size_t i = 0; i < val.length(); ++i) {
-            buf.push_back(reinterpret_cast<const int8_t *>(val.data())[i]);
+            write((val.data())[i]);
         }
     }
 
-    void write(const char * val) const {
+    void write(const char * val) {
         write(std::string(val));
     }
 
-    void write(const enum ggml_type & val) const {
+    void write(const enum ggml_type & val) {
         write(int32_t(val));
     }
 
-    void write(const enum gguf_type & val) const {
+    void write(const enum gguf_type & val) {
         write(int32_t(val));
     }
 
-    void write(const struct gguf_kv & kv) const {
+    void write(const struct gguf_kv & kv) {
         const uint64_t ne = kv.get_ne();
 
         write(kv.get_key());
@@ -1253,7 +1254,7 @@ struct gguf_writer {
         }
     }
 
-    void write_tensor_meta(const struct gguf_tensor_info & info) const {
+    void write_tensor_meta(const struct gguf_tensor_info & info) {
         write(info.t.name);
 
         const uint32_t n_dims = ggml_n_dims(&info.t);
@@ -1266,14 +1267,33 @@ struct gguf_writer {
         write(info.offset);
     }
 
-    void pad(const size_t alignment) const {
-        while (buf.size() % alignment != 0) {
+    void pad(const size_t alignment) {
+        while (written_bytes % alignment != 0) {
             const int8_t zero = 0;
             write(zero);
         }
     }
+};
+
+// vector buffer based writer
+struct gguf_writer_buf final : public gguf_writer_base {
+    std::vector<int8_t> & buf;
+
+    gguf_writer_buf(std::vector<int8_t> & buf) : buf(buf) {}
+
+    using gguf_writer_base::write;
+
+    void write(const int8_t val) override {
+        buf.push_back(val);
+        written_bytes++;
+    }
 
-    void write_tensor_data(const struct gguf_tensor_info & info, const size_t offset_data, const size_t alignment) const {
+    void write(const std::vector<int8_t> & val) override {
+        buf.insert(buf.end(), val.begin(), val.end());
+        written_bytes += val.size();
+    }
+
+    void write_tensor_data(const struct gguf_tensor_info & info, const size_t offset_data, const size_t alignment) override {
         GGML_ASSERT(buf.size() - offset_data == info.offset);
 
         GGML_ASSERT(ggml_is_contiguous(&info.t));
@@ -1287,14 +1307,58 @@ struct gguf_writer {
             GGML_ASSERT(info.t.data);
             memcpy(buf.data() + offset, info.t.data, nbytes);
         }
+        written_bytes += nbytes;
 
         pad(alignment);
     }
 };
 
-void gguf_write_to_buf(const struct gguf_context * ctx, std::vector<int8_t> & buf, bool only_meta) {
-    const struct gguf_writer gw(buf);
+// file based writer
+struct gguf_writer_file final : public gguf_writer_base {
+    FILE * file;
+
+    gguf_writer_file(FILE* file) : file(file) {}
+
+    using gguf_writer_base::write;
+
+    void write(const int8_t val) override {
+        const auto real_val = static_cast<uint8_t>(val);
+        const auto ret = fputc(real_val, file);
+        written_bytes++;
+        if (ret != real_val) {
+            throw std::runtime_error("unexpected fputc result '" + std::to_string(ret) + "' instead of '" + std::to_string((int)real_val) + "'");
+        }
+    }
+
+    void write(const std::vector<int8_t> & val) override {
+        const auto ret = fwrite(val.data(), 1, val.size(), file);
+        written_bytes += val.size();
+        if (ret != val.size()) {
+            throw std::runtime_error("unexpected fwrite number of bytes written, '" + std::to_string(ret) + "' instead of '" + std::to_string(val.size()) + "'");
+        }
+    }
+
+    void write_tensor_data(const struct gguf_tensor_info & info, const size_t offset_data, const size_t alignment) override {
+        GGML_ASSERT(written_bytes - offset_data == info.offset);
+
+        GGML_ASSERT(ggml_is_contiguous(&info.t));
+        const size_t nbytes = ggml_nbytes(&info.t);
 
+        std::vector<int8_t> buf(nbytes);
+        if (info.t.buffer) {
+            ggml_backend_tensor_get(&info.t, buf.data(), 0, nbytes);
+        } else {
+            GGML_ASSERT(info.t.data);
+            memcpy(buf.data(), info.t.data, nbytes);
+        }
+        write(buf);
+
+        pad(alignment);
+    }
+};
+
+template <typename writer_t>
+static void gguf_write_out(const struct gguf_context * ctx, writer_t & gw, bool only_meta) {
     const int64_t n_kv      = gguf_get_n_kv(ctx);
     const int64_t n_tensors = gguf_get_n_tensors(ctx);
 
@@ -1324,7 +1388,7 @@ void gguf_write_to_buf(const struct gguf_context * ctx, std::vector<int8_t> & bu
         return;
     }
 
-    const size_t offset_data = gw.buf.size();
+    const size_t offset_data = gw.written_bytes;
 
     // write tensor data
     for (int64_t i = 0; i < n_tensors; ++i) {
@@ -1332,6 +1396,11 @@ void gguf_write_to_buf(const struct gguf_context * ctx, std::vector<int8_t> & bu
     }
 }
 
+void gguf_write_to_buf(const struct gguf_context * ctx, std::vector<int8_t> & buf, bool only_meta) {
+    gguf_writer_buf gw(buf);
+    gguf_write_out(ctx, gw, only_meta);
+}
+
 bool gguf_write_to_file(const struct gguf_context * ctx, const char * fname, bool only_meta) {
     FILE * file = ggml_fopen(fname, "wb");
 
@@ -1340,11 +1409,17 @@ bool gguf_write_to_file(const struct gguf_context * ctx, const char * fname, boo
         return false;
     }
 
-    std::vector<int8_t> buf;
-    gguf_write_to_buf(ctx, buf, only_meta);
-    const bool ok = fwrite(buf.data(), 1, buf.size(), file) == buf.size();
+    try {
+        gguf_writer_file gw(file);
+        gguf_write_out(ctx, gw, only_meta);
+    } catch (const std::runtime_error& ex) {
+        GGML_LOG_ERROR("%s: failed to write GGUF data into '%s': %s\n", __func__, fname, ex.what());
+        fclose(file);
+        return false;
+    }
+
     fclose(file);
-    return ok;
+    return true;
 }
 
 size_t gguf_get_meta_size(const struct gguf_context * ctx) {