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, 41 insertions, 0 deletions

diff --git a/video/out/gpu/spirv.h b/video/out/gpu/spirv.h
new file mode 100644
index 0000000000..e3dbd4f52a
--- /dev/null
+++ b/video/out/gpu/spirv.h
@@ -0,0 +1,41 @@
+#pragma once
+
+#include "common/msg.h"
+#include "common/common.h"
+#include "context.h"
+
+enum glsl_shader {
+    GLSL_SHADER_VERTEX,
+    GLSL_SHADER_FRAGMENT,
+    GLSL_SHADER_COMPUTE,
+};
+
+#define SPIRV_NAME_MAX_LEN 32
+
+struct spirv_compiler {
+    char name[SPIRV_NAME_MAX_LEN];
+    const struct spirv_compiler_fns *fns;
+    struct mp_log *log;
+    void *priv;
+
+    const char *required_ext; // or NULL
+    int glsl_version;         // GLSL version supported
+    int compiler_version;     // for cache invalidation, may be left as 0
+    int ra_caps;              // RA_CAP_* provided by this implementation, if any
+};
+
+struct spirv_compiler_fns {
+    // Compile GLSL to SPIR-V, under GL_KHR_vulkan_glsl semantics.
+    bool (*compile_glsl)(struct spirv_compiler *spirv, void *tactx,
+                         enum glsl_shader type, const char *glsl,
+                         struct bstr *out_spirv);
+
+    // Called by spirv_compiler_init / ra_ctx_destroy. These don't need to
+    // allocate/free ctx->spirv, that is done by the caller
+    bool (*init)(struct ra_ctx *ctx);
+    void (*uninit)(struct ra_ctx *ctx); // optional
+};
+
+// Initializes ctx->spirv to a valid SPIR-V compiler, or returns false on
+// failure. Cleanup will be handled by ra_ctx_destroy.
+bool spirv_compiler_init(struct ra_ctx *ctx);