Clang static analyzer can be run as part of oclint run. It contains slower and more complex memory related checks.

Clang static analyzer is about checking logic errors - unused variables, memory leaks, etc.

OCLint does things like warn if there are too many non-comment-lines-of-code in a method, or too many methods per class. It's more about keeping tabs on complexity and code cleanlyness than true static analysis.

Ideally, use both! If you're using Xcode you can enable "analyze" for all builds. Highly recommended if it doesn't break your build times.

IIRC, clang-tidy includes all clang-analyzer checks.