HLSL to SPIR-V

Hi, I have been using glslc & glslang to convert hlsl shaders to spir-v. But it doesnt seems to take into account RootSignatures of HLSL and hence misses bindings. Is there any way to fix this. Or if I create SPIR-V from HLSL or GLSL, Can I later modify the bindings and them get modified SPIR-V?