These changes are a result of prototype work in PIX to support shader debugging for DXR,, which was an exercise to figure out how to support libraries in general in PIX. These changes are the result. It's all about iterating over all the library functions, rather than "the" entry point function.
In addition, to have something concrete to submit to a driver, there's the addition of codegen for the shader debugging "prolog", which chooses at runtime whether or not to emit instrumentation data for a given shader invocation based on its (in this case) thread id. This last is not yet ready for production in PIX, in that it is necessary but not sufficient to enable DXR shader debugging.
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