Inspecting tool for the GHC pipeline through GHC plugin
ghc-specter is an inspecting tool and visualizer of internal states of the GHC compilation pipeline via GHC plugins and hooks. Haskell developers often need investigation in the middle of the compilation, for example, to identify blocking compilation steps dominating the build time or to investigate a problematic Template Haskell code, but have to rely only on built-in GHC logging or resort to a custom modification of the GHC source code. As a GHC driver plugin, invoked by simple command-line flags, ghc-specter collects the relevant information directly inside from the GHC compilation and send to a visualizer daemon on live. The user can also pause and intervene the GHC process in the middle of compilation to inspect the GHC internal state and inspect the the compilation process in an interactive session.
$ nix develop
$ cabal run ghc-specter-daemon:exe:ghc-specter-daemon
Run GHC with -fplugin Plugin.GHCSpecter and -plugin-package ghc-specter-plugin.
If ghc-specter-plugin is already specified as the dependency of the project,
the latter is not necessary.
Example:
$ cabal build --ghc-options "-fplugin Plugin.GHCSpecter -plugin-package ghc-specter-plugin"