Excessive memory usage and slow performance when using OpenUSD/Pixar headers

[bobbrow]

Issue #13205 reports a performance issue with IntelliSense in a project that uses headers from the OpenUSD project.

[bobbrow]

We discovered that the Pixar headers support both MSVC's conforming and non-conforming preprocessors. When you configure your project and IntelliSense to use the newer standards conforming preprocessor, these headers do not require the deep recursion and memory usage in the IntelliSense process.

If you are using these headers and MSVC as your compiler, you need to ensure that IntelliSense is configured to use the conforming preprocessor. Adding this into your configurations in c_cpp_properties.json and/or updating your build system to generate a compile_commands.json file with this flag set will resolve this issue for you:

            "compilerArgs": [
                "/Zc:preprocessor"
            ],