That's quite believable to me for an old codebase. Command line utilities at Google routinely reached hundreds of megabytes in binary size due to static linking

That's quite believable to me for an old codebase. Command line utilities at Google routinely reached hundreds of megabytes in binary size due to static linking of everything. A Bloomberg server is surely far larger and more complex than those tools, so gigabytes isn't unbelievable. Binary code can be quite bloated compared to source code. It depends a lot on the encoding. The same author as this blog post has another actually much more interesting one on how Go compiles common constructs. It's rather enlightening as the example generated assembly (implicitly) explains why Go compiles so fast. It has to be the dumbest, least optimising compiler I've ever seen. Very short and trivial source code constructs like function calls balloon into pages of instructions, far far more than a C compiler would generate. C++ compilers also have a reputation for generating bloaty code, but that's mostly due to compile-time specialisation of containers and the way template expansion works. If you write C-as-C++ then you get pretty tight binaries.