Merge branch 'master' of ssh://darcs.haskell.org/srv/darcs/ghc

compiler/ghc.cabal.in

@@ -139,6 +139,7 @@ Library
         Literal
         Llvm
         Llvm.AbsSyn
+        Llvm.MetaData
         Llvm.PpLlvm
         Llvm.Types
         LlvmCodeGen

compiler/llvmGen/Llvm.hs

@@ -32,27 +32,30 @@ module Llvm (
 
         -- * Variables and Type System
         LlvmVar(..), LlvmStatic(..), LlvmLit(..), LlvmType(..),
-        LlvmAlias, LMGlobal, LMString, LMSection, LMAlign,
+        LlvmAlias, LMGlobal(..), LMString, LMSection, LMAlign,
+        LMConst(..),
 
         -- ** Some basic types
         i64, i32, i16, i8, i1, i8Ptr, llvmWord, llvmWordPtr,
 
         -- ** Metadata types
-        LlvmMetaVal(..), LlvmMetaUnamed(..), LlvmMeta(..), MetaData,
+        MetaExpr(..), MetaAnnot(..), MetaDecl(..),
 
         -- ** Operations on the type system.
-        isGlobal, getLitType, getLit, getName, getPlainName, getVarType,
-        getLink, getStatType, getGlobalVar, getGlobalType, pVarLift, pVarLower,
+        isGlobal, getLitType, getVarType,
+        getLink, getStatType, pVarLift, pVarLower,
         pLift, pLower, isInt, isFloat, isPointer, isVector, llvmWidthInBits,
 
         -- * Pretty Printing
+        ppLit, ppName, ppPlainName,
         ppLlvmModule, ppLlvmComments, ppLlvmComment, ppLlvmGlobals,
         ppLlvmGlobal, ppLlvmFunctionDecls, ppLlvmFunctionDecl, ppLlvmFunctions,
         ppLlvmFunction, ppLlvmAlias, ppLlvmAliases, ppLlvmMetas, ppLlvmMeta,
 
     ) where
 
 import Llvm.AbsSyn
+import Llvm.MetaData
 import Llvm.PpLlvm
 import Llvm.Types
 

compiler/llvmGen/Llvm/AbsSyn.hs

@@ -4,6 +4,7 @@
 
 module Llvm.AbsSyn where
 
+import Llvm.MetaData
 import Llvm.Types
 
 import Unique
@@ -32,7 +33,7 @@ data LlvmModule = LlvmModule  {
     modAliases   :: [LlvmAlias],
 
     -- | LLVM meta data.
-    modMeta      :: [LlvmMeta],
+    modMeta      :: [MetaDecl],
 
     -- | Global variables to include in the module.
     modGlobals   :: [LMGlobal],
@@ -165,11 +166,9 @@ data LlvmStatement
   {- |
     A LLVM statement with metadata attached to it.
   -}
-  | MetaStmt [MetaData] LlvmStatement
+  | MetaStmt [MetaAnnot] LlvmStatement
 
-  deriving (Show, Eq)
-
-type MetaData = (LMString, LlvmMetaUnamed)
+  deriving (Eq)
 
 
 -- | Llvm Expressions
@@ -252,6 +251,17 @@ data LlvmExpression
   -}
   | Call LlvmCallType LlvmVar [LlvmVar] [LlvmFuncAttr]
 
+  {- |
+    Call a function as above but potentially taking metadata as arguments.
+      * tailJumps: CallType to signal if the function should be tail called
+      * fnptrval:  An LLVM value containing a pointer to a function to be
+                   invoked. Can be indirect. Should be LMFunction type.
+      * args:      Arguments that may include metadata.
+      * attrs:     A list of function attributes for the call. Only NoReturn,
+                   NoUnwind, ReadOnly and ReadNone are valid here.
+  -}
+  | CallM LlvmCallType LlvmVar [MetaExpr] [LlvmFuncAttr]
+
   {- |
     Merge variables from different basic blocks which are predecessors of this
     basic block in a new variable of type tp.
@@ -278,7 +288,7 @@ data LlvmExpression
   {- |
     A LLVM expression with metadata attached to it.
   -}
-  | MetaExpr [MetaData] LlvmExpression
+  | MExpr [MetaAnnot] LlvmExpression
 
-  deriving (Show, Eq)
+  deriving (Eq)
 

compiler/llvmGen/Llvm/MetaData.hs

@@ -0,0 +1,84 @@
+--------------------------------------------------------------------------------
+-- | The LLVM Metadata System.
+--
+-- The LLVM metadata feature is poorly documented but roughly follows the
+-- following design:
+-- * Metadata can be constructed in a few different ways (See below).
+-- * After which it can either be attached to LLVM statements to pass along
+-- extra information to the optimizer and code generator OR specificially named
+-- metadata has an affect on the whole module (i.e., linking behaviour).
+--
+--
+-- # Constructing metadata
+-- Metadata comes largely in three forms:
+--
+-- * Metadata expressions -- these are the raw metadata values that encode
+--   information. They consist of metadata strings, metadata nodes, regular
+--   LLVM values (both literals and references to global variables) and
+--   metadata expressions (i.e., recursive data type). Some examples:
+--     !{ metadata !"hello", metadata !0, i32 0 }
+--     !{ metadata !1, metadata !{ i32 0 } }
+--
+-- * Metadata nodes -- global metadata variables that attach a metadata
+--   expression to a number. For example:
+--     !0 = metadata !{ [<metadata expressions>] !}
+--
+-- * Named metadata -- global metadata variables that attach a metadata nodes
+--   to a name. Used ONLY to communicated module level information to LLVM
+--   through a meaningful name. For example:
+--     !llvm.module.linkage = !{ !0, !1 }
+--
+--
+-- # Using Metadata
+-- Using metadata depends on the form it is in:
+--
+-- * Attach to instructions -- metadata can be attached to LLVM instructions
+--   using a specific reference as follows:
+--     %l = load i32* @glob, !nontemporal !10
+--     %m = load i32* @glob, !nontemporal !{ i32 0, metadata !{ i32 0 } }
+--   Only metadata nodes or expressions can be attached, named metadata cannot.
+--   Refer to LLVM documentation for which instructions take metadata and its
+--   meaning.
+--
+-- * As arguments -- llvm functions can take metadata as arguments, for
+--   example:
+--     call void @llvm.dbg.value(metadata !{ i32 0 }, i64 0, metadata !1)
+--   As with instructions, only metadata nodes or expressions can be attached.
+--
+-- * As a named metadata -- Here the metadata is simply declared in global
+--   scope using a specific name to communicate module level information to LLVM.
+--   For example:
+--     !llvm.module.linkage = !{ !0, !1 }
+--
+module Llvm.MetaData where
+
+import Llvm.Types
+
+import Outputable
+
+-- | LLVM metadata expressions
+data MetaExpr = MetaStr LMString
+              | MetaNode Int
+              | MetaVar LlvmVar
+              | MetaStruct [MetaExpr]
+              deriving (Eq)
+
+instance Outputable MetaExpr where
+  ppr (MetaStr    s ) = text "metadata !\"" <> ftext s <> char '"'
+  ppr (MetaNode   n ) = text "metadata !" <> int n
+  ppr (MetaVar    v ) = ppr v
+  ppr (MetaStruct es) = text "metadata !{ " <> ppCommaJoin es <> char '}'
+
+-- | Associates some metadata with a specific label for attaching to an
+-- instruction.
+data MetaAnnot = MetaAnnot LMString MetaExpr
+               deriving (Eq)
+
+-- | Metadata declarations. Metadata can only be declared in global scope.
+data MetaDecl
+    -- | Named metadata. Only used for communicating module information to
+    -- LLVM. ('!name = !{ [!<n>] }' form).
+    = MetaNamed LMString [Int]
+    -- | Metadata node declaration.
+    -- ('!0 = metadata !{ <metadata expression> }' form).
+    | MetaUnamed Int MetaExpr