动态开关的宏导致Shader内存过大

#pragma multi_compile _ A
#pragma multi_compile _ B 
#pragma multi_compile _ C

Keywords always included into build: A B C

8 keyword variants used in scene:

<no keywords defined>
C
B
B C
A
A C
A B
A B C

<no keywords defined>
C
B
B C
A
A C

using UnityEngine;
using UnityEngine.Rendering;

class MyCustomBuildProcessor : IPreprocessShaders
{

    ShaderKeyword A = new ShaderKeyword("A");
    ShaderKeyword B = new ShaderKeyword("B");


    public int callbackOrder { get { return 0; } }
   
    public void OnProcessShader(Shader shader, ShaderSnippetData snippet, IList<ShaderCompilerData> data)
    {

        if ("Unlit/Custom1" != shader.name)
        {
            return;
        }
  
        for (int i = data.Count - 1; i >= 0; --i)
        {
            //当组合中同时包含A和B的时候剥离这个shader
            if (data[i].shaderKeywordSet.IsEnabled(A) && data[i].shaderKeywordSet.IsEnabled(B))
            {
                data.RemoveAt(i);
            }
        }
    }
}