Modulebase-4.23.0.0Haskell2010

GHC.Stack.CloneStack

This module exposes an interface for capturing the state of a thread's execution stack for diagnostics purposes: cloneMyStack, cloneThreadStack.

Such a "cloned" stack can be decoded with decode to a stack trace, given that the -finfo-table-map is enabled.

2 types
3 values

Packagebase-4.23.0.0
Exports5
LanguageHaskell2010
LicenceBSD-3-Clause
SourceCloneStack.hs

datadata StackSnapshot

A frozen snapshot of the state of an execution stack.

Constructors

StackSnapshot !StackSnapshot#

datadata StackEntry

Representation for the source location where a return frame was pushed on the stack. This happens every time when a case ... of scrutinee is evaluated.

Constructors

StackEntry
- functionName :: String
- moduleName :: String
- srcLoc :: String
- closureType :: ClosureType

Instances2Eq, Show

Eq StackEntryDefined in ghc-internal-10.0.0 · GHC.Internal.Stack.Decode
Show StackEntryDefined in ghc-internal-10.0.0 · GHC.Internal.Stack.Decode

valuecloneMyStack :: IO StackSnapshot

Clone the stack of the executing thread

valuecloneThreadStack :: ThreadId -> IO StackSnapshot

Clone the stack of a thread identified by its ThreadId

valuedecode :: StackSnapshot -> IO [StackEntry]

Decode a StackSnapshot to a stacktrace (a list of StackEntry). The stack trace is created from return frames with according InfoProvEnt entries. To generate them, use the GHC flag -finfo-table-map. If there are no InfoProvEnt entries, an empty list is returned.

Please note:

To gather StackEntry from libraries, these have to be compiled with -finfo-table-map, too.
Due to optimizations by GHC (e.g. inlining) the stacktrace may change with different GHC parameters and versions.
The stack trace is empty (by design) if there are no return frames on the stack. (These are pushed every time when a case ... of scrutinee is evaluated.)