ggml: Add initial WebGPU backend (#14521)

* Minimal setup of webgpu backend with dawn. Just prints out the adapter and segfaults * Initialize webgpu device * Making progress on setting up the backend * Finish more boilerplate/utility functions * Organize file and work on alloc buffer * Add webgpu_context to prepare for actually running some shaders * Work on memset and add shader loading * Work on memset polyfill * Implement set_tensor as webgpu WriteBuffer, remove host_buffer stubs since webgpu doesn't support it * Implement get_tensor and buffer_clear * Finish rest of setup * Start work on compute graph * Basic mat mul working * Work on emscripten build * Basic WebGPU backend instructions * Use EMSCRIPTEN flag * Work on passing ci, implement 4d tensor multiplication * Pass thread safety test * Implement permuting for mul_mat and cpy * minor cleanups * Address feedback * Remove division by type size in cpy op * Fix formatting and add github action workflows for vulkan and metal (m-series) webgpu backends * Fix name * Fix macos dawn prefix path
2025-07-16 18:18:51 +03:00
parent b0f0ecc3dc
commit 21c021745d
14 changed files with 1337 additions and 0 deletions
@@ -0,0 +1,40 @@
+@group(0) @binding(0)
+var<storage, read_write> output_buffer: array<u32>;
+
+struct Params {
+    offset: u32, // in bytes
+    size: u32,   // in bytes
+    value: u32,  // 4 8-bit values, which are either repeating (memset_tensor) or may be separate (cleaning up unaligned set_tensor operations)
+};
+
+@group(0) @binding(1)
+var<uniform> params: Params;
+
+override wg_size: u32;
+override bytes_per_thread: u32;
+
+@compute @workgroup_size(wg_size)
+fn main(@builtin(global_invocation_id) gid: vec3<u32>) {
+    let i = gid.x * bytes_per_thread;
+    let start = params.offset;
+    let end = params.offset + params.size;
+
+    for (var j: u32 = 0u; j < bytes_per_thread; j = j + 1u) {
+        let byte_index = start + i + j;
+        if (byte_index + 4u <= end) {
+            output_buffer[(byte_index >> 2u)] = params.value;
+        } else {
+            // Handle tail (unaligned)
+            for (var k: u32 = 0u; k < 4u; k = k + 1u) {
+                let idx = byte_index + k;
+                if (idx < end) {
+                    let word_idx = idx >> 2u;
+                    let byte_offset = (idx & 3u) * 8u;
+                    let mask = ~(0xffu << byte_offset);
+                    let existing = output_buffer[word_idx];
+                    output_buffer[word_idx] = (existing & mask) | ((params.value & 0xffu) << byte_offset);
+                }
+            }
+        }
+    }
+}