Change the way module initialisation is done (#3252, #4417)

Previously the code generator generated small code fragments labelled
with __stginit_M for each module M, and these performed whatever
initialisation was necessary for that module and recursively invoked
the initialisation functions for imported modules.  This appraoch had
drawbacks:

 - FFI users had to call hs_add_root() to ensure the correct
   initialisation routines were called.  This is a non-standard,
   and ugly, API.

 - unless we were using -split-objs, the __stginit dependencies would
   entail linking the whole transitive closure of modules imported,
   whether they were actually used or not.  In an extreme case (#4387,
   #4417), a module from GHC might be imported for use in Template
   Haskell or an annotation, and that would force the whole of GHC to
   be needlessly linked into the final executable.

So now instead we do our initialisation with C functions marked with
__attribute__((constructor)), which are automatically invoked at
program startup time (or DSO load-time).  The C initialisers are
emitted into the stub.c file.  This means that every time we compile
with -prof or -hpc, we now get a stub file, but thanks to #3687 that
is now invisible to the user.

There are some refactorings in the RTS (particularly for HPC) to
handle the fact that initialisers now get run earlier than they did
before.

The __stginit symbols are still generated, and the hs_add_root()
function still exists (but does nothing), for backwards compatibility.

1 files changed, 1 insertions, 52 deletions

diff --git a/compiler/codeGen/CgProf.hs b/compiler/codeGen/CgProf.hs
index 0cf209e89c..243aa1d89a 100644
--- a/compiler/codeGen/CgProf.hs
+++ b/compiler/codeGen/CgProf.hs
@@ -16,8 +16,7 @@ module CgProf (
 	costCentreFrom, 
 	curCCS, curCCSAddr,
 	emitCostCentreDecl, emitCostCentreStackDecl, 
-	emitRegisterCC, emitRegisterCCS,
-	emitSetCCC, emitCCS,
+        emitSetCCC, emitCCS,
 
 	-- Lag/drag/void stuff
 	ldvEnter, ldvEnterClosure, ldvRecordCreate
@@ -348,56 +347,6 @@ sizeof_ccs_words
    (ws,ms) = SIZEOF_CostCentreStack `divMod` wORD_SIZE
 
 -- ---------------------------------------------------------------------------
--- Registering CCs and CCSs
-
---   (cc)->link = CC_LIST;
---   CC_LIST = (cc);
---   (cc)->ccID = CC_ID++;
-
-emitRegisterCC :: CostCentre -> Code
-emitRegisterCC cc = do
-  { tmp <- newTemp cInt
-  ; stmtsC [
-     CmmStore (cmmOffsetB cc_lit oFFSET_CostCentre_link)
-		 (CmmLoad cC_LIST bWord),
-     CmmStore cC_LIST cc_lit,
-     CmmAssign (CmmLocal tmp) (CmmLoad cC_ID cInt),
-     CmmStore (cmmOffsetB cc_lit oFFSET_CostCentre_ccID) (CmmReg (CmmLocal tmp)),
-     CmmStore cC_ID (cmmRegOffB (CmmLocal tmp) 1)
-   ]
-  }
-  where
-    cc_lit = CmmLit (CmmLabel (mkCCLabel cc))
-
---  (ccs)->prevStack = CCS_LIST;
---  CCS_LIST = (ccs);
---  (ccs)->ccsID = CCS_ID++;
-
-emitRegisterCCS :: CostCentreStack -> Code
-emitRegisterCCS ccs = do
-  { tmp <- newTemp cInt
-  ; stmtsC [
-     CmmStore (cmmOffsetB ccs_lit oFFSET_CostCentreStack_prevStack) 
-			(CmmLoad cCS_LIST bWord),
-     CmmStore cCS_LIST ccs_lit,
-     CmmAssign (CmmLocal tmp) (CmmLoad cCS_ID cInt),
-     CmmStore (cmmOffsetB ccs_lit oFFSET_CostCentreStack_ccsID) (CmmReg (CmmLocal tmp)),
-     CmmStore cCS_ID (cmmRegOffB (CmmLocal tmp) 1)
-   ]
-  }
-  where
-    ccs_lit = CmmLit (CmmLabel (mkCCSLabel ccs))
-
-
-cC_LIST, cC_ID :: CmmExpr
-cC_LIST = CmmLit (CmmLabel (mkCmmDataLabel rtsPackageId (fsLit "CC_LIST")))
-cC_ID   = CmmLit (CmmLabel (mkCmmDataLabel rtsPackageId (fsLit "CC_ID")))
-
-cCS_LIST, cCS_ID :: CmmExpr
-cCS_LIST = CmmLit (CmmLabel (mkCmmDataLabel rtsPackageId (fsLit "CCS_LIST")))
-cCS_ID   = CmmLit (CmmLabel (mkCmmDataLabel rtsPackageId (fsLit "CCS_ID")))
-
--- ---------------------------------------------------------------------------
 -- Set the current cost centre stack
 
 emitSetCCC :: CostCentre -> Code