Instead, let me break it down in a way that even my grandma could understand (if she knew what coding was).

So, what is LTO? Well, imagine this: You have a big project with lots of files and functions. When you compile everything together, the linker has to go through all those files and figure out which parts are used where. This can take forever if your codebase is huge or if there’s a lot of interdependence between different modules.

That’s where LTO comes in! Instead of waiting until the end to optimize everything, GCC (the compiler we use) generates intermediate language (IL) for each file and then combines them all into one big IL soup. This allows the linker to do its job faster because it doesn’t have to worry about figuring out which parts are used where they’re already optimized!

LTO also lets you use different optimization levels for each file without having to recompile everything from scratch. This is great if you want to save time and resources while still getting the best possible performance. And since GCC can handle ELF (the container format used by most Linux distros), LTO works on pretty much any platform that supports it.

So, how do we use this magical feature? Well, first you need to make sure your target supports one of the binary formats supported by LTO: PE-COFF or Mach-O for Windows and MacOS respectively, or ELF (the default format used by most Linux distros). Then, all you have to do is add a few flags when compiling your code. For example:

# This script compiles a C program using the gcc compiler with the -flto flag for Link Time Optimization (LTO).

# First, we need to specify the input file, which in this case is "my_program.c".
gcc -flto my_program.c

# The -flto flag enables LTO, which optimizes the code during the linking stage rather than just the compilation stage.
# This can result in faster and more efficient code execution.

# Additionally, we can add more flags to further optimize the code:
gcc -flto -O3 -march=native my_program.c

# The -O3 flag enables level 3 optimization, which performs more aggressive optimizations on the code.
# The -march=native flag allows the compiler to use the specific instruction set of the machine it is being compiled on, further optimizing the code for that specific system.

# Overall, this script allows for the compilation of a C program with LTO and additional optimization flags for improved performance.

This will generate IL for each file and then combine them into one big soup using lto1 (the LTO front end). If you have multiple source files, just pass them all to the compiler like this:

# This script compiles multiple source files into one executable using the LTO front end.
# The -flto flag enables link-time optimization.
# The source files are passed as arguments to the compiler.

gcc -flto -o my_program my_program.c another_file.c yet_another_one.c
# -o specifies the output file name, in this case "my_program"
# The source files are listed after the output file name, separated by spaces.

# Note: It is good practice to use the -o flag to specify the output file name, rather than relying on the default executable name generated by the compiler.

And that’s it! Your code will be optimized at link time instead of compile time, which can result in significant performance improvements (especially for large projects). Plus, since LTO is implemented as a plugin for the gold linker, you don’t have to worry about any special linker features or weird dependencies.

It might not be the most exciting topic out there, but trust me, it can make your life (and your code) a whole lot easier. And if you ever get stuck or need some help, just reach out to us on our forums or social media channels. We’re always here to lend a hand!