micro-opt: replace stmGetEnclosingTRec() with a field access

While fixing #3578 I noticed that this function was just a field
access to StgTRecHeader, so I inlined it manually.

includes/mkDerivedConstants.c

@@ -342,6 +342,8 @@ main(int argc, char *argv[])
 
     closure_field(StgAtomicInvariant, code);
 
+    closure_field(StgTRecHeader, enclosing_trec);
+
     closure_size(StgCatchSTMFrame);
     closure_field(StgCatchSTMFrame, handler);
     closure_field(StgCatchSTMFrame, code);

rts/Exception.cmm

@@ -398,7 +398,7 @@ retry_pop_stack:
       W_ r;
       trec = StgTSO_trec(CurrentTSO);
       (r) = foreign "C" stmValidateNestOfTransactions(trec "ptr") [];
-      ("ptr" outer) = foreign "C" stmGetEnclosingTRec(trec "ptr") [];
+      outer  = StgTRecHeader_enclosing_trec(trec);
       foreign "C" stmAbortTransaction(MyCapability() "ptr", trec "ptr") [];
       foreign "C" stmFreeAbortedTRec(MyCapability() "ptr", trec "ptr") [];
 
@@ -498,7 +498,7 @@ retry_pop_stack:
     } else {
       W_ trec, outer;
       trec = StgTSO_trec(CurrentTSO);
-      ("ptr" outer) = foreign "C" stmGetEnclosingTRec(trec "ptr") [];
+      outer  = StgTRecHeader_enclosing_trec(trec);
       foreign "C" stmAbortTransaction(MyCapability() "ptr", trec "ptr") [];
       foreign "C" stmFreeAbortedTRec(MyCapability() "ptr", trec "ptr") [];
       StgTSO_trec(CurrentTSO) = outer;

rts/PrimOps.cmm

@@ -650,7 +650,7 @@ INFO_TABLE_RET(stg_catch_retry_frame, CATCH_RETRY_FRAME,
 
    frame = Sp;
    trec = StgTSO_trec(CurrentTSO);
-   ("ptr" outer) = foreign "C" stmGetEnclosingTRec(trec "ptr") [];
+   outer  = StgTRecHeader_enclosing_trec(trec);
    (r) = foreign "C" stmCommitNestedTransaction(MyCapability() "ptr", trec "ptr") [];
    if (r != 0) {
      /* Succeeded (either first branch or second branch) */
@@ -685,7 +685,7 @@ INFO_TABLE_RET(stg_atomically_frame, ATOMICALLY_FRAME,
   frame  = Sp;
   trec   = StgTSO_trec(CurrentTSO);
   result = R1;
-  ("ptr" outer) = foreign "C" stmGetEnclosingTRec(trec "ptr") [];
+  outer  = StgTRecHeader_enclosing_trec(trec);
 
   if (outer == NO_TREC) {
     /* First time back at the atomically frame -- pick up invariants */
@@ -782,7 +782,7 @@ INFO_TABLE_RET(stg_catch_stm_frame, CATCH_STM_FRAME,
       W_ r, frame, trec, outer;
       frame = Sp;
       trec = StgTSO_trec(CurrentTSO);
-      ("ptr" outer) = foreign "C" stmGetEnclosingTRec(trec "ptr") [];
+      outer  = StgTRecHeader_enclosing_trec(trec);
       (r) = foreign "C" stmCommitNestedTransaction(MyCapability() "ptr", trec "ptr") [];
       if (r != 0) {
         /* Commit succeeded */
@@ -917,7 +917,7 @@ retry_pop_stack:
   Sp = StgTSO_sp(CurrentTSO);
   frame = Sp;
   trec = StgTSO_trec(CurrentTSO);
-  ("ptr" outer) = foreign "C" stmGetEnclosingTRec(trec "ptr") [];
+  outer  = StgTRecHeader_enclosing_trec(trec);
 
   if (frame_type == CATCH_RETRY_FRAME) {
     // The retry reaches a CATCH_RETRY_FRAME before the atomic frame
@@ -950,7 +950,7 @@ retry_pop_stack:
     foreign "C" stmFreeAbortedTRec(MyCapability() "ptr", trec "ptr") [];
     trec = outer;
     StgTSO_trec(CurrentTSO) = trec;
-    ("ptr" outer) = foreign "C" stmGetEnclosingTRec(trec "ptr") [];
+    outer  = StgTRecHeader_enclosing_trec(trec);
   }
   ASSERT(outer == NO_TREC);
 

rts/RaiseAsync.c

@@ -884,7 +884,7 @@ raiseAsync(Capability *cap, StgTSO *tso, StgClosure *exception,
 	    
 	case ATOMICALLY_FRAME:
 	    if (stop_at_atomically) {
-		ASSERT(stmGetEnclosingTRec(tso->trec) == NO_TREC);
+		ASSERT(tso->trec->enclosing_trec == NO_TREC);
 		stmCondemnTransaction(cap, tso -> trec);
 		tso->sp = frame - 2;
                 // The ATOMICALLY_FRAME expects to be returned a
@@ -914,7 +914,7 @@ raiseAsync(Capability *cap, StgTSO *tso, StgClosure *exception,
 
 		{
             StgTRecHeader *trec = tso -> trec;
-            StgTRecHeader *outer = stmGetEnclosingTRec(trec);
+            StgTRecHeader *outer = trec -> enclosing_trec;
 	    debugTrace(DEBUG_stm, 
 		       "found atomically block delivering async exception");
             stmAbortTransaction(cap, trec);

rts/STM.c

@@ -1026,16 +1026,6 @@ void stmCondemnTransaction(Capability *cap,
 
 /*......................................................................*/
 
-StgTRecHeader *stmGetEnclosingTRec(StgTRecHeader *trec) {
-  StgTRecHeader *outer;
-  TRACE("%p : stmGetEnclosingTRec", trec);
-  outer = trec -> enclosing_trec;
-  TRACE("%p : stmGetEnclosingTRec()=%p", trec, outer);
-  return outer;
-}
-
-/*......................................................................*/
-
 StgBool stmValidateNestOfTransactions(StgTRecHeader *trec) {
   StgTRecHeader *t;
   StgBool result;

rts/STM.h

@@ -83,13 +83,6 @@ void stmFreeAbortedTRec(Capability *cap, StgTRecHeader *trec);
 
 void stmCondemnTransaction(Capability *cap, StgTRecHeader *trec);
 
-/*
- * Return the trec within which the specified trec was created (not
- * valid if trec==NO_TREC).
- */
-
-StgTRecHeader *stmGetEnclosingTRec(StgTRecHeader *trec);
-
 /*----------------------------------------------------------------------
 
    Validation

rts/Schedule.c

@@ -1062,7 +1062,7 @@ schedulePostRunThread (Capability *cap, StgTSO *t)
             // partially-evaluated thunks on the heap.
             throwToSingleThreaded_(cap, t, NULL, rtsTrue);
             
-            ASSERT(get_itbl((StgClosure *)t->sp)->type == ATOMICALLY_FRAME);
+//            ASSERT(get_itbl((StgClosure *)t->sp)->type == ATOMICALLY_FRAME);
         }
     }
 
@@ -2564,7 +2564,7 @@ findRetryFrameHelper (StgTSO *tso)
       
     case CATCH_STM_FRAME: {
         StgTRecHeader *trec = tso -> trec;
-	StgTRecHeader *outer = stmGetEnclosingTRec(trec);
+	StgTRecHeader *outer = trec -> enclosing_trec;
         debugTrace(DEBUG_stm,
 		   "found CATCH_STM_FRAME at %p during retry", p);
         debugTrace(DEBUG_stm, "trec=%p outer=%p", trec, outer);