lavu/vulkan: add support for using libshaderc as a GLSL compiler

It's got a much better API that's actually maintained, it eliminates
race conditions, it comes with a pkg-config file by default, and
unfortunately isn't currently packaged by Debian or other large
distributions.

2 files changed, 126 insertions, 0 deletions

diff --git a/libavutil/vulkan.c b/libavutil/vulkan.c
index 3a70afe6a5..a6463de622 100644
--- a/libavutil/vulkan.c
+++ b/libavutil/vulkan.c
@@ -23,6 +23,8 @@
 
 #if CONFIG_LIBGLSLANG
 #include "vulkan_glslang.c"
+#elif CONFIG_LIBSHADERC
+#include "vulkan_shaderc.c"
 #endif
 
 /* Generic macro for creating contexts which need to keep their addresses
@@ -859,6 +861,8 @@ int ff_vk_compile_shader(FFVulkanContext *s, FFVkSPIRVShader *shd,
     if (!s->spirv_compiler) {
 #if CONFIG_LIBGLSLANG
         s->spirv_compiler = ff_vk_glslang_init();
+#elif CONFIG_LIBSHADERC
+        s->spirv_compiler = ff_vk_shaderc_init();
 #else
         return AVERROR(ENOSYS);
 #endif
diff --git a/libavutil/vulkan_shaderc.c b/libavutil/vulkan_shaderc.c
new file mode 100644
index 0000000000..bd40edf187
--- /dev/null
+++ b/libavutil/vulkan_shaderc.c
@@ -0,0 +1,122 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <shaderc/shaderc.h>
+
+#include "mem.h"
+
+static int shdc_shader_compile(FFVkSPIRVCompiler *ctx, void *avctx,
+                               FFVkSPIRVShader *shd, uint8_t **data,
+                               size_t *size, const char *entrypoint,
+                               void **opaque)
+{
+    int loglevel, err, warn, ret;
+    const char *status, *message;
+    shaderc_compilation_result_t res;
+    static const char *shdc_result[] = {
+        [shaderc_compilation_status_success]            = "success",
+        [shaderc_compilation_status_invalid_stage]      = "invalid stage",
+        [shaderc_compilation_status_compilation_error]  = "error",
+        [shaderc_compilation_status_internal_error]     = "internal error",
+        [shaderc_compilation_status_null_result_object] = "no result",
+        [shaderc_compilation_status_invalid_assembly]   = "invalid assembly",
+    };
+    static const shaderc_shader_kind shdc_kind[] = {
+        [VK_SHADER_STAGE_VERTEX_BIT]   = shaderc_glsl_vertex_shader,
+        [VK_SHADER_STAGE_FRAGMENT_BIT] = shaderc_glsl_fragment_shader,
+        [VK_SHADER_STAGE_COMPUTE_BIT]  = shaderc_glsl_compute_shader,
+    };
+
+    shaderc_compile_options_t opts = shaderc_compile_options_initialize();
+    if (!opts)
+        return AVERROR(ENOMEM);
+
+    shaderc_compile_options_set_target_env(opts, shaderc_target_env_vulkan,
+                                           shaderc_env_version_vulkan_1_2);
+    shaderc_compile_options_set_target_spirv(opts, shaderc_spirv_version_1_5);
+    shaderc_compile_options_set_optimization_level(opts,
+                                                   shaderc_optimization_level_performance);
+
+    res = shaderc_compile_into_spv((shaderc_compiler_t)ctx->priv,
+                                   shd->src.str, strlen(shd->src.str),
+                                   shdc_kind[shd->shader.stage],
+                                   shd->name, entrypoint, opts);
+    shaderc_compile_options_release(opts);
+
+    ret = shaderc_result_get_compilation_status(res);
+    err = shaderc_result_get_num_errors(res);
+    warn = shaderc_result_get_num_warnings(res);
+    message = shaderc_result_get_error_message(res);
+
+    loglevel = err ? AV_LOG_ERROR : warn ? AV_LOG_WARNING : AV_LOG_VERBOSE;
+
+    ff_vk_print_shader(avctx, shd, loglevel);
+    if (message && (err || warn))
+        av_log(avctx, loglevel, "%s\n", message);
+    status = ret < FF_ARRAY_ELEMS(shdc_result) ? shdc_result[ret] : "unknown";
+    av_log(avctx, loglevel, "shaderc compile status '%s' (%d errors, %d warnings)\n",
+           status, err, warn);
+
+    if (err > 0)
+        return AVERROR(EINVAL);
+
+    *data = (uint8_t *)shaderc_result_get_bytes(res);
+    *size = shaderc_result_get_length(res);
+    *opaque = res;
+
+    return 0;
+}
+
+static void shdc_shader_free(FFVkSPIRVCompiler *ctx, void **opaque)
+{
+    if (!opaque || !*opaque)
+        return;
+
+    shaderc_result_release((shaderc_compilation_result_t)*opaque);
+    *opaque = NULL;
+}
+
+static void shdc_uninit(FFVkSPIRVCompiler **ctx)
+{
+    FFVkSPIRVCompiler *s;
+
+    if (!ctx || !*ctx)
+        return;
+
+    s = *ctx;
+
+    shaderc_compiler_release((shaderc_compiler_t)s->priv);
+    av_freep(ctx);
+}
+
+static FFVkSPIRVCompiler *ff_vk_shaderc_init(void)
+{
+    FFVkSPIRVCompiler *ret = av_mallocz(sizeof(*ret));
+    if (!ret)
+        return NULL;
+
+    ret->compile_shader = shdc_shader_compile;
+    ret->free_shader    = shdc_shader_free;
+    ret->uninit         = shdc_uninit;
+
+    ret->priv           = (void *)shaderc_compiler_initialize();
+    if (!ret->priv)
+        av_freep(&ret);
+
+    return ret;
+}