Storage image decorators are not parsed

[juliusikkala]

I wanted to check whether a shader has marked a given storage image as readonly. I assume that this would result in SPV_REFLECT_DECORATION_NON_WRITABLE being visible somewhere, but this doesn't seem to be the case. Both SpvReflectDescriptorBinding.block.decoration_flags and SpvReflectDescriptorBinding.type_description->decoration_flags are zero regardless of the memory qualifier on the GLSL side.

I'm not particularly familiar with SPIR-V intricacies, so I don't really know which one of these two would be the right place for the flags for storage images. They're not really blocks, so maybe the type description? But it looks like the only SpvReflectPrvNodes with the correct decorator present are skipped on this line:

SPIRV-Reflect/spirv_reflect.c

Line 1832 in 5f6e13e

if (! p_node->is_type) {

Maybe a SpvReflectDecorationFlags decoration_flags; could be added to SpvReflectImageTraits instead? Or to SpvReflectDescriptorBinding directly?

Also, looks like there are no tests for storage images. Here's a simple shader to reproduce the issue:

#version 450
#pragma shader_stage(compute)

layout (local_size_x = 16, local_size_y = 16, local_size_z = 1) in;

layout(set = 0, binding = 0, rgba32f) uniform readonly image2D input_image;
layout(set = 0, binding = 1, rgba32f) uniform writeonly image2D output_image;

void main() {
    ivec2 p = ivec2(gl_GlobalInvocationID.xy);
    imageStore(output_image, p, imageLoad(input_image, p));
}

With the spirv-reflect program, there's no NON_WRITABLE in sight. I tested with the master branch in its current state.

[chaoticbob]

Hi - added decoration_flags to SpvReflectDescriptorBinding per your suggestion. It seemed like the most logical place to go for SPV_REFLECT_DECORATION_NON_WRITABLE and SPV_REFLECT_DECORATION_NON_READABLE.

I haven't updated spirv-reflect to output NON_WRITABLE and NON_READABLE yet. Need to think of a way to output these without it looking too messy. Also affects the tests which is really a constraint on time right now.

Thanks for the example shader. Let me know if you run into any issues.