Posts Tagged il2cpp

How to See What C# Turns Into

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I’ve been writing a lot recently about the C++ and assembly that C# code turns into when it’s run through IL2CPP and a C++ compiler. Today’s article shows you the steps so that you can see what your own game’s C# code turns into.

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Loops in IL2CPP

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There are many permutations of loops we can write, but what do they compile to? We should know the consequences of using an array versus a List<T>, for versus foreach, caching Length, and other factors. So today’s article dives into the C++ code that IL2CPP outputs when we write these various types of loops to examine the differences. We’ll even go further and look at the ARM assembly that the C++ compiles to and really find out how much overhead our choices are costing us.

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IL2CPP Output: Abstract Classes, Sealed Classes, and Delegates

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This week we continue to look at the C++ that IL2CPP outputs for C# to get a better understanding of what our C# is really doing. Today we’ll look at how abstract methods work, whether casting of sealed classes is faster than non-sealed classes, and what happens when creating a delegate.

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Three More IL2CPP Surprises

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The story usually has three parts. First, find the highest CPU cost functions in a profiler. Second, look at the corresponding C++ code that IL2CPP generated from C#. Third, stop using more parts of C#. Today’s article explores some more IL2CPP output and discovers some more areas of C# that are shockingly expensive to use.

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Three IL2CPP Optimizations

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This week we’ll take a break from the C++ Scripting series to explore three optimizations we can make to our C# code so that IL2CPP generates faster C++ code for us. We’ll cover three areas that yield big speedups: casting, array bounds checking, and null checking.

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Getting the Size of a Struct at Compile Time

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I continue to learn a lot by reading the C++ code that IL2CPP outputs. Like reading decompiled code, it gives some insight into what what Unity’s build process is doing with the C# we give it. This week I learned that sizeof(MyStruct) isn’t a compile-time constant like it is in C++. Because of that, IL2CPP generates some less-than-ideal C++ code every time you use it. Today’s article shows the process I went through to work around that issue and ends up with some code you can drop into your project to avoid the problem.

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Three Surprises I Encountered While Reading IL2CPP Output

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We code in C#, but that’s just a starting point. Our C# code is compiled to DLLs and then converted into C++ where it’s compiled again to machine code. The good news is that this isn’t a black box! I’ve recently been reading through the C++ code that IL2CPP outputs and learning quite a lot. Today’s article is about some of the surprises that I encountered and how you can change your C# code to avoid some nasty pitfalls.

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The Magic of LINQ Expressions

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LINQ expressions aren’t the same thing as LINQ queries. They’re more like reflection for the syntax of C# itself. It’s a fascinating—and powerful—area of the language and I’ll be exploring it a little in today’s article.

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IL2CPP Slowdown (Partially Solved)

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The new IL2CPP scripting backend in Unity 4.6.2 and 5.0 is supposed to be much faster than the old Mono backend. I ran some benchmarks, but mostly found slowdowns compared to Mono. Today’s article shows the tests I ran, the results I got, and wonders why the IL2CPP version seems so slow. Perhaps one of you, dear readers, knows the reason why. Update: Part of the reason why has been discovered. Read on for updated results.

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