[SPIR-V] Shader target stage is undefined

[DBouma]

According to the wiki the __SHADER_TARGET_STAGE is predefined when compiling a shader.

The predefined macro, __SHADER_TARGET_STAGE, is set at compilation time depending on the option provided to the -T flag to one of the above values.

However this does not seem to be the case in SPIR-V, as the shader stage identifiers do not seem to be set accordingly.
For example when compiling a compute shader:

...
bool checkForComputeStage() {
#if __SHADER_TARGET_STAGE == __SHADER_STAGE_COMPUTE
    return true;
#else
    return false;
#endif
}

void main() {
    float4 result;
    if(checkForComputeStage() {
        result = float4(1,0,0,1);
    } else {
        result = float4(0,1,0,1);
    }
    
    //write result away to a texture or buffer
}

In this case checkForComputeStage() always returns false.

[jaebaek]

It's weird .. I think it should work. We will take a look.