Commit f7b384c1e for llama.cpp

commit f7b384c1e5c5b2c5b321a4a7cefea04b15b54cb7
Author: Adrien Gallouët <angt@huggingface.co>
Date:   Wed Sep 30 23:59:46 2026 +0200

    ggml-opencl : replace alloca() with std::vector (#29765)

    Signed-off-by: Adrien Gallouët <angt@huggingface.co>

diff --git a/ggml/src/ggml-opencl/ggml-opencl.cpp b/ggml/src/ggml-opencl/ggml-opencl.cpp
index 4dcc9e957..74bddd703 100644
--- a/ggml/src/ggml-opencl/ggml-opencl.cpp
+++ b/ggml/src/ggml-opencl/ggml-opencl.cpp
@@ -6612,14 +6612,14 @@ static bool ggml_opencl_is_device_supported(ggml_backend_dev_t dev) {
 #endif

     size_t ext_str_size;
-    clGetDeviceInfo(dev_ctx->device, CL_DEVICE_EXTENSIONS, 0, NULL, &ext_str_size);
+    CL_CHECK(clGetDeviceInfo(dev_ctx->device, CL_DEVICE_EXTENSIONS, 0, NULL, &ext_str_size));

-    char *ext_buffer = (char *)alloca(ext_str_size + 1);
-    clGetDeviceInfo(dev_ctx->device, CL_DEVICE_EXTENSIONS, ext_str_size, ext_buffer, NULL);
+    std::vector<char> ext_buffer(ext_str_size + 1);
+    CL_CHECK(clGetDeviceInfo(dev_ctx->device, CL_DEVICE_EXTENSIONS, ext_str_size, ext_buffer.data(), NULL));
     ext_buffer[ext_str_size] = '\0';

     // Check if ext_buffer contains cl_khr_fp16
-    bool fp16_support = strstr(ext_buffer, "cl_khr_fp16") != NULL;
+    bool fp16_support = strstr(ext_buffer.data(), "cl_khr_fp16") != NULL;
     if (!fp16_support) {
         GGML_LOG_WARN("ggml_opencl: device does not support FP16\n");
         return false;
@@ -6627,8 +6627,8 @@ static bool ggml_opencl_is_device_supported(ggml_backend_dev_t dev) {

     // If OpenCL 3.0 is supported, then check for cl_khr_subgroups, which becomes
     // optional in OpenCL 3.0 (cl_khr_subgroup is mandatory in OpenCL 2.x)
-    if (opencl_c_version.major == 3 && strstr(ext_buffer, "cl_khr_subgroups") == NULL &&
-        strstr(ext_buffer, "cl_intel_subgroups") == NULL) {
+    if (opencl_c_version.major == 3 && strstr(ext_buffer.data(), "cl_khr_subgroups") == NULL &&
+        strstr(ext_buffer.data(), "cl_intel_subgroups") == NULL) {
         GGML_LOG_WARN("ggml_opencl: device does not support subgroups (cl_khr_subgroups or cl_intel_subgroups) "
             "(note that subgroups is an optional feature in OpenCL 3.0)\n");
         return false;
@@ -6691,13 +6691,13 @@ static ggml_backend_opencl_context * ggml_cl_init(ggml_backend_dev_t dev) {

     // Check driver version
     size_t driver_version_str_size;
-    clGetDeviceInfo(device, CL_DRIVER_VERSION, 0, NULL, &driver_version_str_size);
-    char *driver_version = (char *)alloca(driver_version_str_size + 1);
-    clGetDeviceInfo(device, CL_DRIVER_VERSION, driver_version_str_size, driver_version, NULL);
+    CL_CHECK(clGetDeviceInfo(device, CL_DRIVER_VERSION, 0, NULL, &driver_version_str_size));
+    std::vector<char> driver_version(driver_version_str_size + 1);
+    CL_CHECK(clGetDeviceInfo(device, CL_DRIVER_VERSION, driver_version_str_size, driver_version.data(), NULL));
     driver_version[driver_version_str_size] = '\0';
-    backend_ctx->driver_version = driver_version;
+    backend_ctx->driver_version = driver_version.data();

-    backend_ctx->adreno_cl_compiler_version = get_adreno_cl_compiler_version(driver_version);
+    backend_ctx->adreno_cl_compiler_version = get_adreno_cl_compiler_version(driver_version.data());
     backend_ctx->has_vector_subgroup_broadcast =
         (backend_ctx->adreno_cl_compiler_version.type == E031 && backend_ctx->adreno_cl_compiler_version.major >= 47) ||
         (backend_ctx->adreno_cl_compiler_version.type == DX   && backend_ctx->adreno_cl_compiler_version.major >= 17);
@@ -6713,33 +6713,33 @@ static ggml_backend_opencl_context * ggml_cl_init(ggml_backend_dev_t dev) {
         !backend_ctx->adreno_cl_compiler_version.newer_than_or_same(E031, 45, 0, 0);

     size_t ext_str_size;
-    clGetDeviceInfo(device, CL_DEVICE_EXTENSIONS, 0, NULL, &ext_str_size);
-    char *ext_buffer = (char *)alloca(ext_str_size + 1);
-    clGetDeviceInfo(device, CL_DEVICE_EXTENSIONS, ext_str_size, ext_buffer, NULL);
+    CL_CHECK(clGetDeviceInfo(device, CL_DEVICE_EXTENSIONS, 0, NULL, &ext_str_size));
+    std::vector<char> ext_buffer(ext_str_size + 1);
+    CL_CHECK(clGetDeviceInfo(device, CL_DEVICE_EXTENSIONS, ext_str_size, ext_buffer.data(), NULL));
     ext_buffer[ext_str_size] = '\0'; // ensure it is null terminated

     // check support for qcom_subgroup_shuffle
-    if (strstr(ext_buffer, "cl_qcom_subgroup_shuffle") != NULL) {
+    if (strstr(ext_buffer.data(), "cl_qcom_subgroup_shuffle") != NULL) {
         backend_ctx->has_qcom_subgroup_shuffle = true;
     }

     // Check if ext_buffer contains cl_khr_fp16
-    backend_ctx->fp16_support = strstr(ext_buffer, "cl_khr_fp16") != NULL;
+    backend_ctx->fp16_support = strstr(ext_buffer.data(), "cl_khr_fp16") != NULL;

     // check Adreno large buffer support
-    backend_ctx->adreno_has_large_buffer = strstr(ext_buffer, "cl_qcom_large_buffer") != NULL;
+    backend_ctx->adreno_has_large_buffer = strstr(ext_buffer.data(), "cl_qcom_large_buffer") != NULL;

     // subgroup shuffle support (N_SPLIT>1 FA kernel)
-    backend_ctx->has_qcom_subgroup_shuffle = strstr(ext_buffer, "cl_qcom_subgroup_shuffle") != NULL;
+    backend_ctx->has_qcom_subgroup_shuffle = strstr(ext_buffer.data(), "cl_qcom_subgroup_shuffle") != NULL;
     backend_ctx->has_subgroup_shuffle =
-        strstr(ext_buffer, "cl_khr_subgroup_shuffle") != NULL ||
+        strstr(ext_buffer.data(), "cl_khr_subgroup_shuffle") != NULL ||
         backend_ctx->has_qcom_subgroup_shuffle;

     // check for cl_khr_integer_dot_product
     // cl_qcom_dot_product8 uses signed * unsigned
     // while cl_khr_integer_dot_product uses signed * signed -- we stick with khr for now
     backend_ctx->has_integer_dot =
-        strstr(ext_buffer, "cl_khr_integer_dot_product") != NULL;
+        strstr(ext_buffer.data(), "cl_khr_integer_dot_product") != NULL;

     cl_uint base_align_in_bits;
     CL_CHECK(clGetDeviceInfo(device, CL_DEVICE_MEM_BASE_ADDR_ALIGN, sizeof(cl_uint), &base_align_in_bits, NULL));