MOTIVATION:
  When compiling Agda source via the current default backend MAlonzo,
  this generates Haskell code, with automatically generated Haskell
  identifiers of the shape ``MAlonzo.Code.MyHaskellisedModuleName.dXYZ''
  for Agda entities that translate to Haskell program-level variables.
  If the MAlonzo-generated Haskell is compiled for profiling,
  and run with profiling enabled, the GHC run-time system writes
  these identifiers to the *.prof (and *.hp) files.
  This makes direct inspection of *.prof files of limited use for the
  Agda developer. The tool ``agda-ghc-names fixprof'' included here
  translates these *.prof files to *.agdaIdents.prof,
  where each dXYZ is replaced with the Agda identifier it originates from.


agda-ghc-names extract <dir>
  assumes that all *.hs files below <dir> have been generated by MAlonzo,
  and extracts the mapping from their Haskell names to the original
  Agda names. Typically, <dir> will be the --compile-dir argument
  used when compiling an Agda program.
  The mapping is saved in <dir>/agda-ghc-name-cache.dat .

  For a medium-size project, this requires around 3GB of heap space,
  and takes around 100 seconds.
  (The heavy heap usage is due to the use of haskell-src-exts
    for parsing the MAlonzo-generated Haskell files, which may be quite large.)

agda-ghc-names fixprof {+m} {+s} <dir> <progname>.prof
  generates <progname>.agdaIdents*.prof by replacing Haskell identifiers
  in <progname>.prof by Agda identifiers, as far as these can be found
  in MAlonzo-compiled *.hs files below <dir>.
  This reads <dir>/agda-ghc-name-cache.dat if it already exists,
  and otherwise generates it in the same way as
  ``agda-ghc-names extract <dir>''.
  The option ``+m'' includes also the original Haskell module column
  in the output.
  The option ``+s'' includes also the original Haskell source location column
  added in GHC-8 in the output.

agda-ghc-names find <dir> {hsIdents}
  also reads <dir>/agda-ghc-name-cache.dat if it already exists,
  and otherwise generates it in the same ways as ``agda-ghc-names extract <dir>''.
  Subsequently:
   * For each qualified Haskell identifier in {hsIdents}
     (which typically start with ``MAlonzo.Code.''),
     it prints the Agda identifiers corresponding to it.
     If {hsIdents} contains exactly one qualified identifier,
     then only the Agda identifier is printed;
     otherwise the mapping ``<hsIdent> |-> <agdaIdent>''
     is printed for each identifier given.
   * Each unqualified Haskell identifier in {hsIdents}
     is looked up in all module maps.
  If none are given on the command line, they are read from standard input.

agda-ghc-names find -m <dir> {hsModNames}
  instead dumps the whole association list for each module specified.