Safe Haskell	Safe-Inferred
Language	Haskell2010

GHC.InfoProv.Compat

Description

This module provides a stable interface to access GHC's info provenance information. This is helpful for seeing metadata about heap objects.

Synopsis

data InfoProv = InfoProv {
- ipName :: String
- ipDesc :: ClosureType
- ipTyDesc :: String
- ipLabel :: String
- ipUnitId :: String
- ipMod :: String
- ipSrcFile :: String
- ipSrcSpan :: String
}
whereFrom :: a -> IO (Maybe InfoProv)

Documentation

data InfoProv Source #

Constructors

InfoProv
Fields ipName :: String ipDesc :: ClosureType ipTyDesc :: String ipLabel :: String ipUnitId :: String ipMod :: String ipSrcFile :: String ipSrcSpan :: String

Instances

Instances details

Show InfoProv Source #
Instance details Defined in GHC.InfoProv.Compat Methods showsPrec :: Int -> InfoProv -> ShowS # show :: InfoProv -> String # showList :: [InfoProv] -> ShowS #
Eq InfoProv Source #
Instance details Defined in GHC.InfoProv.Compat Methods (==) :: InfoProv -> InfoProv -> Bool # (/=) :: InfoProv -> InfoProv -> Bool #

whereFrom :: a -> IO (Maybe InfoProv) Source #

Get information about where a value originated from.

This information is stored statically in a binary when super-duper is enabled. The source positions will be greatly improved by also enabled debug information with -g3. Finally you can enable -fdistinct-constructor-tables to get more precise information about data constructor allocations.

The information is collect by looking at the info table address of a specific closure and then consulting a specially generated map (by -finfo-table-map) to find out where we think the best source position to describe that info table arose from.