Compilers

Recently, I was bored and decided to test the performance of a 4x4 matrix multiply. I wanted to compare how GCC and Clang optimize the same code with different flags. So I manually wrote a benchmark harness using a neat trick: a C file that’s also a valid shell script. The idea is simple. You embed shell commands in C comments at the top of the file. When you run sh benchmark.c, the shell sees the commands and executes them to compile and run the benchmark. When the C compiler processes it, the commands are just comments. ...

I recently implemented BigObj COFF file parsing in cgo (golang/go#24341). In the process, I quickly discovered that Microsoft doesn’t document the binary format anywhere. Their official documentation is the only reference they have to BigObj as far as I can tell, and it doesn’t say anything about the binary format. I didn’t see any other blogs or resources covering this topic either. I figured it out by reading binutils and LLVM source code, so I’m documenting what I learned while the knowledge is still fresh in my memory. ...

Cross compilation is a common task during development, but different compilers and programming languages handle it in their own ways, and I wanted to write about the various flavors of trade-offs and design decisions that you will find across different tooling. I feel like I have absorbed a lot of information about how cross compilation works across different targets, tools and languages, so I figured it was time to condense my knowledge into a blog post. This is not a tutorial, but it still contains practically applicable knowledge. I don’t claim to get every detail correct, merely explaining how things work to my understanding. ...