Cbuffer space and register reflection api problem.

[JKot-Coder]

Hi, I have the following Slang code:

struct FrameParams
{
    float4x4 g_WorldViewProj;
};
ParameterBlock<FrameParams> frame;

uniform float foo;
uniform float bar;

It compiles to this HLSL:

struct FrameParams_0
{
    float4x4 g_WorldViewProj_0;
};

#line 5
cbuffer frame_0 : register(b0, space1)
{
    FrameParams_0 frame_0;
}

#line 5
struct GlobalParams_0
{
    float foo_0;
    float bar_0;
};

#line 5
cbuffer globalParams_0 : register(b0)
{
    GlobalParams_0 globalParams_0;
}

Then I use this code to collect reflection info:

void CollectSets(slang::ProgramLayout* programLayout)
{
    const uint32_t paramCount = programLayout->getParameterCount();
    for (uint32_t i = 0; i < paramCount; i++)
    {
        auto param = programLayout->getParameterByIndex(i);
        auto paramName = param->getName();

        slang::ParameterCategory category = param->getCategory();
        uint32_t binding = param->getBindingIndex();
        uint32_t space = param->getBindingSpace();

        std::cout << "Param " << i << ": " << paramName << std::endl;
        std::cout << "  Category: " << getParameterCategoryStr(category) << std::endl;
        std::cout << "  Binding: " << binding << std::endl;
        std::cout << "  Space: " << space << std::endl;
    }
}

The output looks like this:

Shader params reflection:
Param 0: frame
  Category: SubElementRegisterSpace
  Binding: 1
  Space: 0
Param 1: foo
  Category: Uniform
  Binding: 0
  Space: 0
Param 2: bar
  Category: Uniform
  Binding: 4
  Space: 0

The reflection results don’t seem to match the generated HLSL at all.
All parameters show space = 0, even though frame_0 is clearly using space1.

I can’t tell if this is a bug or if I’m using the reflection API incorrectly.
I also tried using programLayout->getGlobalParamsVarLayout()->getTypeLayout() for reflection, but got the same issue.

What I expected to see:

cbuffer frame : register(b0, space1)
cbuffer globalParams : register(b0, space0)

Could you please explain why the reflection gives everything in space0 and show the correct way to retrieve the actual register and space bindings?

[JKot-Coder]

ACK. I have found answer here #7646. This api confusing as hell.