Modulewherefrom-compat-0.2.0.0Haskell2010

GHC.InfoProv.Compat

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

1 type
1 value

Packagewherefrom-compat-0.2.0.0
Exports2
LanguageHaskell2010
LicenceBSD-2-Clause
SourceCompat.hs

datadata InfoProv

Constructors

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

Instances2Eq, Show

Eq InfoProvDefined in wherefrom-compat-0.2.0.0 · GHC.InfoProv.Compat
Show InfoProvDefined in wherefrom-compat-0.2.0.0 · GHC.InfoProv.Compat

valuewhereFrom :: a -> IO (Maybe InfoProv)

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.