Unexpected VUID-RuntimeSpirv-NonWritable-06340 and VUID-RuntimeSpirv-NonWritable-06341 following check for VUID-RuntimeSpirv-Location-06428

[j-e10]

Environment:

• OS: Linux
• GPU and driver version: AMD MESA
• SDK or header version if building from repo: 1.3.289
• Options enabled (synchronization, best practices, etc.):

Describe the Issue

Starting on commit https://github.com/KhronosGroup/Vulkan-ValidationLayers/commit/08ec2b683f7a54c5be80f7a5ac834ec6a7be17d2, I'm getting VUID-RuntimeSpirv-NonWritable-06340 and VUID-RuntimeSpirv-NonWritable-06341 errors (e.g., vertex/fragment shaders making use of writable storage buffers w/o the vertexStoresAndAtomics/fragmentStoresAndAtomics feature enabled). Earlier VVL commits do not trigger this.

The GLSL shaders in question do use storage buffers but they are all marked readonly.

Expected behavior

No VUID-RuntimeSpirv-NonWritable-06340 and VUID-RuntimeSpirv-NonWritable-06341 errors.

The commit mentioned concerns VUID-RuntimeSpirv-Location-06428 so I think it's a regression.

Valid Usage ID

VUID-RuntimeSpirv-NonWritable-06340 VUID-RuntimeSpirv-NonWritable-06341

[spencer-lunarg]

@j-e10 it would be GREATLY helpful if you could provide the GLSL (or the SPIR-V is better) which causes this false positives as it will help speed up fixing this... I want to make sure this is correct before the next SDK release

[j-e10]

Example GLSL:

fragment

#version 450
layout (location=0) in float i;
layout (location=0) out vec4 o;
void main(void)
{
    o = vec4(i);
}

vertex

#version 450
layout(set=0, binding=16, std430) readonly buffer b_ { float v; } b;
layout(location=0) out float o;
void main(void)
{
    o = b.v;
}

I have a somewhat complex shader building process, but spirv-cross gives me the following GLSL from the final SPIR-V in that process (which matches what I'd expect):

fragment

#version 450

layout(location = 0) out vec4 _9;
layout(location = 0) in float _11;

void main()
{
    _9 = vec4(_11);
}

vertex

#version 450

layout(set = 0, binding = 16, std430) readonly buffer _9_11
{
    float _m0;
} _11;

layout(location = 0) out float _8;

void main()
{
    _8 = _11._m0;
}

Attempting to create a pipeline gives me:

validation layer: Validation Error: [ VUID-RuntimeSpirv-NonWritable-06341 ] Object 0: handle = 0x3b500000003b5, type = VK_OBJECT_TYPE_SHADER_MODULE; | MessageID = 0x116350f | vkCreateGraphicsPipelines(): pCreateInfos[0].pStages[0] vertexPipelineStoresAndAtomics was not enabled. The Vulkan spec states: If vertexPipelineStoresAndAtomics is not enabled, then all storage image, storage texel buffer, and storage buffer variables in the vertex, tessellation, and geometry stages must be decorated with the NonWritable decoration (https://www.khronos.org/registry/vulkan/specs/1.3-extensions/html/vkspec.html#VUID-RuntimeSpirv-NonWritable-06341)

[spencer-lunarg]

So I took

#version 450
layout(set=0, binding=16, std430) readonly buffer b_ { float v; } b;
layout(location=0) out float o;
void main(void) 
{
    o = b.v;
}

and ran glslangValidator -V in.vert -o out.spv and if I run spirv-dis on it I can see

OpMemberDecorate %b_ 0 NonWritable

which is what the error message is pointing out

glslang takes the readonly and maps it to NonWritable in SPIR-V (all Vulkan shader VUs will reference SPIR-V terms, not GLSL terms)

[j-e10]

Right.

If vertexPipelineStoresAndAtomics is not enabled, then all storage image, storage texel buffer, and storage buffer variables in the vertex, tessellation, and geometry stages must be decorated with the NonWritable decoration

I keep vertexPipelineStoresAndAtomics disabled. Therefore, all of my storage images/buffers must be NonWritable; which is the case in the example. Though it's still emitting the error.

[spencer-lunarg]

Sorry I misread this, I think I see the issue, the check is not correctly checking the members of the struct... will get some tests and a fix next week (off for til Monday)