For a long time the tools were either proprietary or GNU. Sadly gcc worked well enough that its policy of not exposing anything that could be abused by proprietary software meant that any tooling that surfaced had to work around the free compiler. Remember the day emacs got full featured refactoring support based on GCC? Stallman singlehandedly killed that for exposing too much. Good C++ tooling only started to turn up when Apple made its move from gcc to llvm/clang and we actually got competition in the free compiler space and a compiler based framework to build tools on top.