1 files changed, 41 insertions, 0 deletions
diff --git a/compiler/GHC/Types/CostCentre/State.hs b/compiler/GHC/Types/CostCentre/State.hs
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+++ b/compiler/GHC/Types/CostCentre/State.hs
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+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+module GHC.Types.CostCentre.State
+   ( CostCentreState
+   , newCostCentreState
+   , CostCentreIndex
+   , unCostCentreIndex
+   , getCCIndex
+   )
+where
+
+import GhcPrelude
+import FastString
+import FastStringEnv
+
+import Data.Data
+import Binary
+
+-- | Per-module state for tracking cost centre indices.
+--
+-- See documentation of 'CostCentre.cc_flavour' for more details.
+newtype CostCentreState = CostCentreState (FastStringEnv Int)
+
+-- | Initialize cost centre state.
+newCostCentreState :: CostCentreState
+newCostCentreState = CostCentreState emptyFsEnv
+
+-- | An index into a given cost centre module,name,flavour set
+newtype CostCentreIndex = CostCentreIndex { unCostCentreIndex :: Int }
+  deriving (Eq, Ord, Data, Binary)
+
+-- | Get a new index for a given cost centre name.
+getCCIndex :: FastString
+           -> CostCentreState
+           -> (CostCentreIndex, CostCentreState)
+getCCIndex nm (CostCentreState m) =
+    (CostCentreIndex idx, CostCentreState m')
+  where
+    m_idx = lookupFsEnv m nm
+    idx = maybe 0 id m_idx
+    m' = extendFsEnv m nm (idx + 1)