SPIRV shader debugger: `OpDebugValue` does not update the value of an vector element. about renderdoc HOT 2 CLOSED

The construction of using DebugValue to index into a vector and using OpAccessChain through a pointer to a structure member to modify the y-component is not currently handled by the RenderDoc source level debugging.

Source

    t.memberB = float3(1, 2, 3);
    t.memberB.y = 4.0;

SPIRV slang

%167 = OpAccessChain %_ptr_Function_v3float %t %int_1
       OpStore %167 %168
%175 = OpAccessChain %_ptr_Function_float %167 %int_1
       OpStore %175 %float_4

For reference: SPIRV glslang construction which does work with RenderDoc source debugging

%86 = OpAccessChain %_ptr_Function_v3float %t %int_1
      OpStore %86 %84
%89 = OpAccessChain %_ptr_Function_float %t %int_1 %uint_1
      OpStore %89 %float_4

from renderdoc.

The difference with glslang and slang's own spirv backend (enabled with -emit-spirv-directly in slangc) is that Slang uses more SSA registers than explicit OpVars and is relying on OpDebugValue to update a debug variable. Therefore we don't use OpDebugDeclare to link a debug variable with an actual variable as done in glslang, but rely more heavily on OpDebugValue.

from renderdoc.