vo_gpu: vulkan: generalize SPIR-V compiler

In addition to the built-in nvidia compiler, we now also support a
backend based on libshaderc. shaderc is sort of like glslang except it
has a C API and is available as a dynamic library.

The generated SPIR-V is now cached alongside the VkPipeline in the
cached_program. We use a special cache header to ensure validity of this
cache before passing it blindly to the vulkan implementation, since
passing invalid SPIR-V can cause all sorts of nasty things. It's also
designed to self-invalidate if the compiler gets better, by offering a
catch-all `int compiler_version` that implementations can use as a cache
invalidation marker.

1 files changed, 78 insertions, 0 deletions

diff --git a/video/out/gpu/spirv.c b/video/out/gpu/spirv.c
new file mode 100644
index 0000000000..9375fd9508
--- /dev/null
+++ b/video/out/gpu/spirv.c
@@ -0,0 +1,78 @@
+#include "common/msg.h"
+#include "options/m_config.h"
+
+#include "spirv.h"
+#include "config.h"
+
+extern const struct spirv_compiler_fns spirv_shaderc;
+extern const struct spirv_compiler_fns spirv_nvidia_builtin;
+
+// in probe-order
+enum {
+    SPIRV_AUTO = 0,
+    SPIRV_SHADERC, // generally preferred, but not packaged everywhere
+    SPIRV_NVIDIA,  // can be useful for testing, only available on nvidia
+};
+
+static const struct spirv_compiler_fns *compilers[] = {
+#if HAVE_SHADERC
+    [SPIRV_SHADERC] = &spirv_shaderc,
+#endif
+#if HAVE_VULKAN
+    [SPIRV_NVIDIA]  = &spirv_nvidia_builtin,
+#endif
+};
+
+static const struct m_opt_choice_alternatives compiler_choices[] = {
+    {"auto",        SPIRV_AUTO},
+#if HAVE_SHADERC
+    {"shaderc",     SPIRV_SHADERC},
+#endif
+#if HAVE_VULKAN
+    {"nvidia",      SPIRV_NVIDIA},
+#endif
+    {0}
+};
+
+struct spirv_opts {
+    int compiler;
+};
+
+#define OPT_BASE_STRUCT struct spirv_opts
+const struct m_sub_options spirv_conf = {
+    .opts = (const struct m_option[]) {
+        OPT_CHOICE_C("spirv-compiler", compiler, 0, compiler_choices),
+        {0}
+    },
+    .size = sizeof(struct spirv_opts),
+};
+
+bool spirv_compiler_init(struct ra_ctx *ctx)
+{
+    void *tmp = talloc_new(NULL);
+    struct spirv_opts *opts = mp_get_config_group(tmp, ctx->global, &spirv_conf);
+    int compiler = opts->compiler;
+    talloc_free(tmp);
+
+    for (int i = SPIRV_AUTO+1; i < MP_ARRAY_SIZE(compilers); i++) {
+        if (compiler != SPIRV_AUTO && i != compiler)
+            continue;
+        if (!compilers[i])
+            continue;
+
+        ctx->spirv = talloc_zero(NULL, struct spirv_compiler);
+        ctx->spirv->log = ctx->log,
+        ctx->spirv->fns = compilers[i];
+
+        const char *name = m_opt_choice_str(compiler_choices, i);
+        strncpy(ctx->spirv->name, name, sizeof(ctx->spirv->name));
+        MP_VERBOSE(ctx, "Initializing SPIR-V compiler '%s'\n", name);
+        if (ctx->spirv->fns->init(ctx))
+            return true;
+        talloc_free(ctx->spirv);
+        ctx->spirv = NULL;
+    }
+
+    MP_ERR(ctx, "Failed initializing SPIR-V compiler!\n");
+    return false;
+}