sift

Sift through Haskell code for analysis purposes

Install

Install so it's available for any projects using this version of GHC:

stack install --copy-compiler-tool

Example use

Use the bindings in sift-bindings/base-4.9.0.0/ to seed the base package. Now you can use the sift trace command and flag up direct or indirect uses of a given binding.

$ sift trace sift-bindings/*/* --flag-binding "ghc-prim GHC.Prim raise#"
Flagged binding: ghc-prim:GHC.Prim.raise#
  Used by aeson:Data.Aeson.Encoding.Builder.day
  Used by aeson:Data.Aeson.Encoding.Builder.digit
  Used by aeson:Data.Aeson.Encoding.Builder.scientific
  Used by aeson:Data.Aeson.Encoding.Builder.timeOfDay64
  Used by aeson:Data.Aeson.Encoding.Builder.timeZone
  Used by aeson:Data.Aeson.Encoding.Builder.twoDigits
  Used by aeson:Data.Aeson.Internal.Time.diffTimeOfDay64
  Used by aeson:Data.Aeson.Parser.Time.seconds
  Used by aeson:Data.Aeson.Parser.Time.timeZone
  Used by aeson:Data.Aeson.Parser.Unescape.unescapeText'
  [snip]
  Used by base:Control.Exception.Base.noMethodBindingError
  Used by base:Control.Exception.Base.nonExhaustiveGuardsError
  Used by base:Control.Exception.Base.patError
  Used by base:Control.Exception.Base.recConError
  Used by base:Control.Exception.Base.recSelError
  Used by base:Control.Exception.Base.runtimeError
  Used by base:Control.Exception.Base.typeError
  Used by base:Control.Monad.Fix.mfix
  [snip]

See full gist for full output.

Discovery

If you're not sure what the proper location for a binding is, search by identifier:

$ sift find sift-bindings/base-4.9.0.0/*.json --ident "fork#"
Binding id: ghc-prim:GHC.Prim.fork#

Generate bindings

For e.g. the aeson package, use sift-compiler in the aeson package directory:

$ SIFT_PACKAGE=aeson stack ghci --with-ghc sift-compiler aeson:lib

(cabal repl should also work similarly!)

That will generate a bunch of files in the current directory for each module:

bindings_main_Data.Aeson.Encode.json
bindings_main_Data.Aeson.Parser.Time.json
bindings_main_Data.Aeson.Encoding.Builder.json
bindings_main_Data.Aeson.Parser.Unescape.json
...

Use this to seed sift as above.