Module hierarchy: Cmm (cf #13009)

1 files changed, 231 insertions, 0 deletions

diff --git a/compiler/GHC/Cmm.hs b/compiler/GHC/Cmm.hs
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+++ b/compiler/GHC/Cmm.hs
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+-- Cmm representations using Hoopl's Graph CmmNode e x.
+{-# LANGUAGE GADTs #-}
+
+module GHC.Cmm (
+     -- * Cmm top-level datatypes
+     CmmProgram, CmmGroup, GenCmmGroup,
+     CmmDecl, GenCmmDecl(..),
+     CmmGraph, GenCmmGraph(..),
+     CmmBlock,
+     RawCmmDecl, RawCmmGroup,
+     Section(..), SectionType(..), CmmStatics(..), CmmStatic(..),
+     isSecConstant,
+
+     -- ** Blocks containing lists
+     GenBasicBlock(..), blockId,
+     ListGraph(..), pprBBlock,
+
+     -- * Info Tables
+     CmmTopInfo(..), CmmStackInfo(..), CmmInfoTable(..), topInfoTable,
+     ClosureTypeInfo(..),
+     ProfilingInfo(..), ConstrDescription,
+
+     -- * Statements, expressions and types
+     module GHC.Cmm.Node,
+     module GHC.Cmm.Expr,
+  ) where
+
+import GhcPrelude
+
+import Id
+import CostCentre
+import GHC.Cmm.CLabel
+import GHC.Cmm.BlockId
+import GHC.Cmm.Node
+import GHC.Runtime.Layout
+import GHC.Cmm.Expr
+import GHC.Cmm.Dataflow.Block
+import GHC.Cmm.Dataflow.Collections
+import GHC.Cmm.Dataflow.Graph
+import GHC.Cmm.Dataflow.Label
+import Outputable
+import Data.ByteString (ByteString)
+
+-----------------------------------------------------------------------------
+--  Cmm, GenCmm
+-----------------------------------------------------------------------------
+
+-- A CmmProgram is a list of CmmGroups
+-- A CmmGroup is a list of top-level declarations
+
+-- When object-splitting is on, each group is compiled into a separate
+-- .o file. So typically we put closely related stuff in a CmmGroup.
+-- Section-splitting follows suit and makes one .text subsection for each
+-- CmmGroup.
+
+type CmmProgram = [CmmGroup]
+
+type GenCmmGroup d h g = [GenCmmDecl d h g]
+type CmmGroup = GenCmmGroup CmmStatics CmmTopInfo CmmGraph
+type RawCmmGroup = GenCmmGroup CmmStatics (LabelMap CmmStatics) CmmGraph
+
+-----------------------------------------------------------------------------
+--  CmmDecl, GenCmmDecl
+-----------------------------------------------------------------------------
+
+-- GenCmmDecl is abstracted over
+--   d, the type of static data elements in CmmData
+--   h, the static info preceding the code of a CmmProc
+--   g, the control-flow graph of a CmmProc
+--
+-- We expect there to be two main instances of this type:
+--   (a) C--, i.e. populated with various C-- constructs
+--   (b) Native code, populated with data/instructions
+
+-- | A top-level chunk, abstracted over the type of the contents of
+-- the basic blocks (Cmm or instructions are the likely instantiations).
+data GenCmmDecl d h g
+  = CmmProc     -- A procedure
+     h                 -- Extra header such as the info table
+     CLabel            -- Entry label
+     [GlobalReg]       -- Registers live on entry. Note that the set of live
+                       -- registers will be correct in generated C-- code, but
+                       -- not in hand-written C-- code. However,
+                       -- splitAtProcPoints calculates correct liveness
+                       -- information for CmmProcs.
+     g                 -- Control-flow graph for the procedure's code
+
+  | CmmData     -- Static data
+        Section
+        d
+
+type CmmDecl = GenCmmDecl CmmStatics CmmTopInfo CmmGraph
+
+type RawCmmDecl
+   = GenCmmDecl
+        CmmStatics
+        (LabelMap CmmStatics)
+        CmmGraph
+
+-----------------------------------------------------------------------------
+--     Graphs
+-----------------------------------------------------------------------------
+
+type CmmGraph = GenCmmGraph CmmNode
+data GenCmmGraph n = CmmGraph { g_entry :: BlockId, g_graph :: Graph n C C }
+type CmmBlock = Block CmmNode C C
+
+-----------------------------------------------------------------------------
+--     Info Tables
+-----------------------------------------------------------------------------
+
+-- | CmmTopInfo is attached to each CmmDecl (see defn of CmmGroup), and contains
+-- the extra info (beyond the executable code) that belongs to that CmmDecl.
+data CmmTopInfo   = TopInfo { info_tbls  :: LabelMap CmmInfoTable
+                            , stack_info :: CmmStackInfo }
+
+topInfoTable :: GenCmmDecl a CmmTopInfo (GenCmmGraph n) -> Maybe CmmInfoTable
+topInfoTable (CmmProc infos _ _ g) = mapLookup (g_entry g) (info_tbls infos)
+topInfoTable _                     = Nothing
+
+data CmmStackInfo
+   = StackInfo {
+       arg_space :: ByteOff,
+               -- number of bytes of arguments on the stack on entry to the
+               -- the proc.  This is filled in by GHC.StgToCmm.codeGen, and
+               -- used by the stack allocator later.
+       updfr_space :: Maybe ByteOff,
+               -- XXX: this never contains anything useful, but it should.
+               -- See comment in GHC.Cmm.LayoutStack.
+       do_layout :: Bool
+               -- Do automatic stack layout for this proc.  This is
+               -- True for all code generated by the code generator,
+               -- but is occasionally False for hand-written Cmm where
+               -- we want to do the stack manipulation manually.
+  }
+
+-- | Info table as a haskell data type
+data CmmInfoTable
+  = CmmInfoTable {
+      cit_lbl  :: CLabel, -- Info table label
+      cit_rep  :: SMRep,
+      cit_prof :: ProfilingInfo,
+      cit_srt  :: Maybe CLabel,   -- empty, or a closure address
+      cit_clo  :: Maybe (Id, CostCentreStack)
+        -- Just (id,ccs) <=> build a static closure later
+        -- Nothing <=> don't build a static closure
+        --
+        -- Static closures for FUNs and THUNKs are *not* generated by
+        -- the code generator, because we might want to add SRT
+        -- entries to them later (for FUNs at least; THUNKs are
+        -- treated the same for consistency). See Note [SRTs] in
+        -- GHC.Cmm.Info.Build, in particular the [FUN] optimisation.
+        --
+        -- This is strictly speaking not a part of the info table that
+        -- will be finally generated, but it's the only convenient
+        -- place to convey this information from the code generator to
+        -- where we build the static closures in
+        -- GHC.Cmm.Info.Build.doSRTs.
+    }
+
+data ProfilingInfo
+  = NoProfilingInfo
+  | ProfilingInfo ByteString ByteString -- closure_type, closure_desc
+
+-----------------------------------------------------------------------------
+--              Static Data
+-----------------------------------------------------------------------------
+
+data SectionType
+  = Text
+  | Data
+  | ReadOnlyData
+  | RelocatableReadOnlyData
+  | UninitialisedData
+  | ReadOnlyData16      -- .rodata.cst16 on x86_64, 16-byte aligned
+  | CString
+  | OtherSection String
+  deriving (Show)
+
+-- | Should a data in this section be considered constant
+isSecConstant :: Section -> Bool
+isSecConstant (Section t _) = case t of
+    Text                    -> True
+    ReadOnlyData            -> True
+    RelocatableReadOnlyData -> True
+    ReadOnlyData16          -> True
+    CString                 -> True
+    Data                    -> False
+    UninitialisedData       -> False
+    (OtherSection _)        -> False
+
+data Section = Section SectionType CLabel
+
+data CmmStatic
+  = CmmStaticLit CmmLit
+        -- a literal value, size given by cmmLitRep of the literal.
+  | CmmUninitialised Int
+        -- uninitialised data, N bytes long
+  | CmmString ByteString
+        -- string of 8-bit values only, not zero terminated.
+
+data CmmStatics
+   = Statics
+       CLabel      -- Label of statics
+       [CmmStatic] -- The static data itself
+
+-- -----------------------------------------------------------------------------
+-- Basic blocks consisting of lists
+
+-- These are used by the LLVM and NCG backends, when populating Cmm
+-- with lists of instructions.
+
+data GenBasicBlock i = BasicBlock BlockId [i]
+
+-- | The branch block id is that of the first block in
+-- the branch, which is that branch's entry point
+blockId :: GenBasicBlock i -> BlockId
+blockId (BasicBlock blk_id _ ) = blk_id
+
+newtype ListGraph i = ListGraph [GenBasicBlock i]
+
+instance Outputable instr => Outputable (ListGraph instr) where
+    ppr (ListGraph blocks) = vcat (map ppr blocks)
+
+instance Outputable instr => Outputable (GenBasicBlock instr) where
+    ppr = pprBBlock
+
+pprBBlock :: Outputable stmt => GenBasicBlock stmt -> SDoc
+pprBBlock (BasicBlock ident stmts) =
+    hang (ppr ident <> colon) 4 (vcat (map ppr stmts))
+