I guess the lines can be a bit blurry especially when the compiled code still relies heavily on dynamic dispatch, but V8 generated machine code for the target C

I guess the lines can be a bit blurry especially when the compiled code still relies heavily on dynamic dispatch, but V8 generated machine code for the target CPU, marked the page as executable, and then it would call that just generated code. I think most people would call that a JIT-compiler. It wasn’t a very advanced compiler in the sense that it generated very inefficient machine code. But it still ran circles around a tree-walking or bytecode interpreter. Over time the compiler became more advanced and multi-tiered, but at the cost of startup time, and mobile was taking off, where memory was more scarce than on desktop. x86 or ARM code is a lot bigger than a specialized bytecode that is optimized for space efficiency. So eventually the Ignition interpreter was added. But unlike some of the other Javascript engines that started as an interpreter and later added native code generation, V8 started out generating native code and only later added a bytecode interpreter.