Using vcc without the runtime/scheduler stuff?

[expenses]

Hi, I'm attempting to use vcc and tried compiling the shader from #40 (comment) with vcc x.c -o x.c.spv. This seems to generate a spir-v binary that has a lot of extra elements, but most problematically it has this descriptor set for lifted globals:

               OpDecorate %_arr_v2float_uint_3 ArrayStride 8
               OpDecorate %_arr_v3float_uint_3 ArrayStride 12
               OpDecorate %_struct_6 Block
               OpMemberDecorate %_struct_6 0 Offset 0
               OpMemberDecorate %_struct_6 1 Offset 64
               OpDecorate %lifted_globals DescriptorSet 0
               OpDecorate %lifted_globals Binding 0
               OpDecorate %_arr_uint_ulong_17 ArrayStride 4
               OpMemberDecorate %_struct_26 0 Offset 0
               OpMemberDecorate %_struct_26 1 Offset 4
               OpDecorate %SubgroupId BuiltIn SubgroupId

These are not used in the actual shader. Is it possible that get rid of the runtime/scheduler stuff like this?

[Hugobros3]

The issue seems to be that the code in question defines constants, and the current behaviour is to place such constants in global memory/address space:

vec3 colors[3] =
{
    (vec3){1.0f, 0.0f, 0.0f},
    (vec3){0.0f, 1.0f, 0.0f},
    (vec3){0.0f, 0.0f, 1.0f}
};

Unfortunately SPIR-V does not provide a way for modules to statically allocate global (device) memory and store some constants in there, so instead the shady runtime component is used to accomplish this through some annotation gymnastics.

Unfortunately the current runtime code is more like a testbed to bring up the language and build demo applications in compute, and not a modular set of middleware functions that could be integrated into other Vulkan codebases. This is probably what you want.

As discussed on discord earlier, a workaround for now is to use private variables instead.