Remove CONSTR_STATIC

Summary:
We currently have two info tables for a constructor

* XXX_con_info: the info table for a heap-resident instance of the
  constructor, It has type CONSTR, or one of the specialised types like
  CONSTR_1_0

* XXX_static_info: the info table for a static instance of this
  constructor, which has type CONSTR_STATIC or CONSTR_STATIC_NOCAF.

I'm getting rid of the latter, and using the `con_info` info table for
both static and dynamic constructors.  For rationale and more details
see Note [static constructors] in SMRep.hs.

I also removed these macros: `isSTATIC()`, `ip_STATIC()`,
`closure_STATIC()`, since they relied on the CONSTR/CONSTR_STATIC
distinction, and anyway HEAP_ALLOCED() does the same job.

Test Plan: validate

Reviewers: bgamari, simonpj, austin, gcampax, hvr, niteria, erikd

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2690

GHC Trac Issues: #12455

2 files changed, 23 insertions, 43 deletions

diff --git a/compiler/codeGen/StgCmm.hs b/compiler/codeGen/StgCmm.hs
index 28ca97d9a2..aac556d43f 100644
--- a/compiler/codeGen/StgCmm.hs
+++ b/compiler/codeGen/StgCmm.hs
@@ -226,41 +226,31 @@ cgDataCon data_con
 
             nonptr_wds   = tot_wds - ptr_wds
 
-            sta_info_tbl = mkDataConInfoTable dflags data_con True  ptr_wds nonptr_wds
-            dyn_info_tbl = mkDataConInfoTable dflags data_con False ptr_wds nonptr_wds
-
-            emit_info info_tbl ticky_code
-                = emitClosureAndInfoTable info_tbl NativeDirectCall []
-                             $ mk_code ticky_code
-
-            mk_code ticky_code
-              = -- NB: the closure pointer is assumed *untagged* on
-                -- entry to a constructor.  If the pointer is tagged,
-                -- then we should not be entering it.  This assumption
-                -- is used in ldvEnter and when tagging the pointer to
-                -- return it.
-                -- NB 2: We don't set CC when entering data (WDP 94/06)
-                do { _ <- ticky_code
-                   ; ldvEnter (CmmReg nodeReg)
-                   ; tickyReturnOldCon (length arg_reps)
-                   ; void $ emitReturn [cmmOffsetB dflags (CmmReg nodeReg) (tagForCon dflags data_con)]
-                   }
-                        -- The case continuation code expects a tagged pointer
+            dyn_info_tbl =
+              mkDataConInfoTable dflags data_con False ptr_wds nonptr_wds
 
             -- We're generating info tables, so we don't know and care about
             -- what the actual arguments are. Using () here as the place holder.
             arg_reps :: [NonVoid PrimRep]
-            arg_reps = [NonVoid (typePrimRep rep_ty) | ty <- dataConRepArgTys data_con
-                                                     , rep_ty <- repTypeArgs ty
-                                                     , not (isVoidTy rep_ty)]
-
-            -- Dynamic closure code for non-nullary constructors only
-        ; when (not (isNullaryRepDataCon data_con))
-                (emit_info dyn_info_tbl tickyEnterDynCon)
-
-                -- Dynamic-Closure first, to reduce forward references
-        ; emit_info sta_info_tbl tickyEnterStaticCon }
-
+            arg_reps = [ NonVoid (typePrimRep rep_ty)
+                       | ty <- dataConRepArgTys data_con
+                       , rep_ty <- repTypeArgs ty
+                       , not (isVoidTy rep_ty)]
+
+        ; emitClosureAndInfoTable dyn_info_tbl NativeDirectCall [] $
+            -- NB: the closure pointer is assumed *untagged* on
+            -- entry to a constructor.  If the pointer is tagged,
+            -- then we should not be entering it.  This assumption
+            -- is used in ldvEnter and when tagging the pointer to
+            -- return it.
+            -- NB 2: We don't set CC when entering data (WDP 94/06)
+            do { tickyEnterDynCon
+               ; ldvEnter (CmmReg nodeReg)
+               ; tickyReturnOldCon (length arg_reps)
+               ; void $ emitReturn [cmmOffsetB dflags (CmmReg nodeReg) (tagForCon dflags data_con)]
+               }
+                    -- The case continuation code expects a tagged pointer
+        }
 
 ---------------------------------------------------------------
 --      Stuff to support splitting
diff --git a/compiler/codeGen/StgCmmClosure.hs b/compiler/codeGen/StgCmmClosure.hs
index 23b803cc56..0ce119b0bb 100644
--- a/compiler/codeGen/StgCmmClosure.hs
+++ b/compiler/codeGen/StgCmmClosure.hs
@@ -1040,12 +1040,8 @@ mkDataConInfoTable dflags data_con is_static ptr_wds nonptr_wds
                 , cit_srt  = NoC_SRT }
  where
    name = dataConName data_con
-
-   info_lbl | is_static = mkStaticInfoTableLabel name NoCafRefs
-            | otherwise = mkConInfoTableLabel    name NoCafRefs
-
+   info_lbl = mkConInfoTableLabel name NoCafRefs
    sm_rep = mkHeapRep dflags is_static ptr_wds nonptr_wds cl_type
-
    cl_type = Constr (dataConTagZ data_con) (dataConIdentity data_con)
 
    prof | not (gopt Opt_SccProfilingOn dflags) = NoProfilingInfo
@@ -1074,16 +1070,10 @@ indStaticInfoTable
 staticClosureNeedsLink :: Bool -> CmmInfoTable -> Bool
 -- A static closure needs a link field to aid the GC when traversing
 -- the static closure graph.  But it only needs such a field if either
---         a) it has an SRT
+--        a) it has an SRT
 --        b) it's a constructor with one or more pointer fields
 -- In case (b), the constructor's fields themselves play the role
 -- of the SRT.
---
--- At this point, the cit_srt field has not been calculated (that
--- happens right at the end of the Cmm pipeline), but we do have the
--- VarSet of CAFs that CoreToStg attached, and if that is empty there
--- will definitely not be an SRT.
---
 staticClosureNeedsLink has_srt CmmInfoTable{ cit_rep = smrep }
   | isConRep smrep         = not (isStaticNoCafCon smrep)
   | otherwise              = has_srt -- needsSRT (cit_srt info_tbl)