base-4.20.2.0: Core data structures and operations

Copyright | (c) The University of Glasgow 2011
License | see libraries/base/LICENSE
Maintainer | ghc-devs@haskell.org
Stability | internal
Portability | non-portable (GHC Extensions)
Safe Haskell | Safe
Language | Haskell2010

GHC.Stack.CCS

Contents

- Call stacks
- Internals

Description

Access to GHC's call-stack simulation

Since: base-4.5.0.0

Synopsis

- currentCallStack :: IO [String]
- whoCreated :: a -> IO [String]
- data CostCentreStack
- data CostCentre
- getCurrentCCS :: dummy -> IO (Ptr CostCentreStack)
- getCCSOf :: a -> IO (Ptr CostCentreStack)
- clearCCS :: IO a -> IO a
- ccsCC :: Ptr CostCentreStack -> IO (Ptr CostCentre)
- ccsParent :: Ptr CostCentreStack -> IO (Ptr CostCentreStack)
- ccLabel :: Ptr CostCentre -> IO CString
- ccModule :: Ptr CostCentre -> IO CString
- ccSrcSpan :: Ptr CostCentre -> IO CString
- ccsToStrings :: Ptr CostCentreStack -> IO [String]
- renderStack :: [String] -> String

# Call stacks

currentCallStack :: IO [String] Source #

Returns a `[String]` representing the current call stack. This can be useful for debugging.

The implementation uses the call-stack simulation maintained by the profiler, so it only works if the program was compiled with `-prof` and contains suitable SCC annotations (e.g. by using `-fprof-auto`). Otherwise, the list returned is likely to be empty or uninformative.

Since: base-4.5.0.0

whoCreated :: a -> IO [String] Source #

Get the stack trace attached to an object.

Since: base-4.5.0.0

# Internals

data CostCentreStack Source #

A cost-centre stack from GHC's cost-center profiler.

data CostCentre Source #

A cost-centre from GHC's cost-center profiler.

getCurrentCCS :: dummy -> IO (Ptr CostCentreStack) Source #

Returns the current `CostCentreStack` (value is `nullPtr` if the current program was not compiled with profiling support). Takes a dummy argument which can be used to avoid the call to `getCurrentCCS` being floated out by the simplifier, which would result in an uninformative stack (CAF).

getCCSOf :: a -> IO (Ptr CostCentreStack) Source #

Get the `CostCentreStack` associated with the given value.

clearCCS :: IO a -> IO a Source #

Run a computation with an empty cost-center stack. For example, this is used by the interpreter to run an interpreted computation without the call stack showing that it was invoked from GHC.

ccsCC :: Ptr CostCentreStack -> IO (Ptr CostCentre) Source #

Get the `CostCentre` at the head of a `CostCentreStack`.

ccsParent :: Ptr CostCentreStack -> IO (Ptr CostCentreStack) Source #

Get the tail of a `CostCentreStack`.

ccLabel :: Ptr CostCentre -> IO CString Source #

Get the label of a `CostCentre`.

ccModule :: Ptr CostCentre -> IO CString Source #

Get the module of a `CostCentre`.

ccSrcSpan :: Ptr CostCentre -> IO CString Source #

Get the source span of a `CostCentre`.

ccsToStrings :: Ptr CostCentreStack -> IO [String] Source #

Format a `CostCentreStack` as a list of lines.

renderStack :: [String] -> String Source #