made the previous changes in parameter passing mechanism and return

value mechanism settable with compile time constants

lang/m2/comp/BigPars

@@ -76,3 +76,18 @@
 				*/
 
 
+!File: bigparam.h
+#define PASS_BIG_VAL_AS_VAR 1	/* define when big value parameters must be
+				   passed as addresses
+				*/
+
+
+!File: bigresult.h
+#define BIG_RESULT_ON_STACK 1	/* define when function results must be
+				   put on the stack; in this case, caller
+				   reserves space for it. When not defined,
+				   callee puts result in global data area and
+				   returns a pointer to it
+				*/
+
+

lang/m2/comp/Makefile

@@ -43,7 +43,7 @@ SRC =	$(CSRC) $(GENC)
 OBJ =	$(COBJ) $(LOBJ) Lpars.o
 
 GENH=	errout.h\
-	idfsize.h numsize.h strsize.h target_sizes.h \
+	idfsize.h numsize.h strsize.h target_sizes.h bigparam.h bigresult.h \
 	inputtype.h density.h squeeze.h nocross.h nostrict.h \
 	def.h debugcst.h type.h Lpars.h node.h desig.h strict3rd.h
 HFILES=		LLlex.h\
@@ -178,6 +178,7 @@ $(CURRDIR)cemain:      $(OBJ) $(CURRDIR)Makefile
 #AUTOAUTOAUTOAUTOAUTOAUTOAUTOAUTO
 LLlex.o: LLlex.h
 LLlex.o: Lpars.h
+LLlex.o: bigparam.h
 LLlex.o: class.h
 LLlex.o: const.h
 LLlex.o: debug.h
@@ -212,6 +213,7 @@ error.o: warning.h
 main.o: LLlex.h
 main.o: Lpars.h
 main.o: SYSTEM.h
+main.o: bigparam.h
 main.o: debug.h
 main.o: debugcst.h
 main.o: def.h
@@ -236,6 +238,7 @@ input.o: f_info.h
 input.o: input.h
 input.o: inputtype.h
 type.o: LLlex.h
+type.o: bigparam.h
 type.o: chk_expr.h
 type.o: const.h
 type.o: debug.h
@@ -253,6 +256,7 @@ type.o: walk.h
 type.o: warning.h
 def.o: LLlex.h
 def.o: Lpars.h
+def.o: bigparam.h
 def.o: debug.h
 def.o: debugcst.h
 def.o: def.h
@@ -270,6 +274,7 @@ misc.o: idf.h
 misc.o: misc.h
 misc.o: node.h
 enter.o: LLlex.h
+enter.o: bigparam.h
 enter.o: debug.h
 enter.o: debugcst.h
 enter.o: def.h
@@ -284,6 +289,7 @@ enter.o: target_sizes.h
 enter.o: type.h
 defmodule.o: LLlex.h
 defmodule.o: Lpars.h
+defmodule.o: bigparam.h
 defmodule.o: debug.h
 defmodule.o: debugcst.h
 defmodule.o: def.h
@@ -299,6 +305,7 @@ defmodule.o: scope.h
 defmodule.o: target_sizes.h
 defmodule.o: type.h
 typequiv.o: LLlex.h
+typequiv.o: bigparam.h
 typequiv.o: debug.h
 typequiv.o: debugcst.h
 typequiv.o: def.h
@@ -311,6 +318,7 @@ typequiv.o: target_sizes.h
 typequiv.o: type.h
 typequiv.o: warning.h
 node.o: LLlex.h
+node.o: bigparam.h
 node.o: debug.h
 node.o: debugcst.h
 node.o: def.h
@@ -321,6 +329,7 @@ node.o: target_sizes.h
 node.o: type.h
 cstoper.o: LLlex.h
 cstoper.o: Lpars.h
+cstoper.o: bigparam.h
 cstoper.o: debug.h
 cstoper.o: debugcst.h
 cstoper.o: idf.h
@@ -332,6 +341,7 @@ cstoper.o: type.h
 cstoper.o: warning.h
 chk_expr.o: LLlex.h
 chk_expr.o: Lpars.h
+chk_expr.o: bigparam.h
 chk_expr.o: chk_expr.h
 chk_expr.o: const.h
 chk_expr.o: debug.h
@@ -349,6 +359,7 @@ chk_expr.o: strict3rd.h
 chk_expr.o: target_sizes.h
 chk_expr.o: type.h
 chk_expr.o: warning.h
+options.o: bigparam.h
 options.o: class.h
 options.o: idfsize.h
 options.o: main.h
@@ -361,6 +372,8 @@ options.o: type.h
 options.o: warning.h
 walk.o: LLlex.h
 walk.o: Lpars.h
+walk.o: bigparam.h
+walk.o: bigresult.h
 walk.o: chk_expr.h
 walk.o: debug.h
 walk.o: debugcst.h
@@ -380,6 +393,7 @@ walk.o: type.h
 walk.o: walk.h
 walk.o: warning.h
 desig.o: LLlex.h
+desig.o: bigparam.h
 desig.o: debug.h
 desig.o: debugcst.h
 desig.o: def.h
@@ -394,6 +408,8 @@ desig.o: walk.h
 desig.o: warning.h
 code.o: LLlex.h
 code.o: Lpars.h
+code.o: bigparam.h
+code.o: bigresult.h
 code.o: debug.h
 code.o: debugcst.h
 code.o: def.h
@@ -407,6 +423,7 @@ code.o: target_sizes.h
 code.o: type.h
 code.o: walk.h
 lookup.o: LLlex.h
+lookup.o: bigparam.h
 lookup.o: debug.h
 lookup.o: debugcst.h
 lookup.o: def.h
@@ -420,6 +437,7 @@ lookup.o: type.h
 tokenfile.o: Lpars.h
 program.o: LLlex.h
 program.o: Lpars.h
+program.o: bigparam.h
 program.o: debug.h
 program.o: debugcst.h
 program.o: def.h
@@ -435,6 +453,7 @@ program.o: type.h
 program.o: warning.h
 declar.o: LLlex.h
 declar.o: Lpars.h
+declar.o: bigparam.h
 declar.o: chk_expr.h
 declar.o: debug.h
 declar.o: debugcst.h
@@ -452,6 +471,7 @@ declar.o: type.h
 declar.o: warning.h
 expression.o: LLlex.h
 expression.o: Lpars.h
+expression.o: bigparam.h
 expression.o: chk_expr.h
 expression.o: const.h
 expression.o: debug.h
@@ -465,6 +485,7 @@ expression.o: type.h
 expression.o: warning.h
 statement.o: LLlex.h
 statement.o: Lpars.h
+statement.o: bigparam.h
 statement.o: def.h
 statement.o: idf.h
 statement.o: nocross.h
@@ -477,6 +498,7 @@ char.o: class.h
 Lpars.o: Lpars.h
 casestat.o: LLlex.h
 casestat.o: Lpars.h
+casestat.o: bigparam.h
 casestat.o: chk_expr.h
 casestat.o: debug.h
 casestat.o: debugcst.h
@@ -490,6 +512,7 @@ casestat.o: target_sizes.h
 casestat.o: type.h
 casestat.o: walk.h
 tmpvar.o: LLlex.h
+tmpvar.o: bigparam.h
 tmpvar.o: debug.h
 tmpvar.o: debugcst.h
 tmpvar.o: def.h
@@ -499,6 +522,7 @@ tmpvar.o: scope.h
 tmpvar.o: target_sizes.h
 tmpvar.o: type.h
 scope.o: LLlex.h
+scope.o: bigparam.h
 scope.o: debug.h
 scope.o: debugcst.h
 scope.o: def.h

lang/m2/comp/SmallPars

@@ -76,3 +76,18 @@
 				*/
 
 
+!File: bigparam.h
+#undef PASS_BIG_VAL_AS_VAR 1	/* define when big value parameters must be
+				   passed as addresses
+				*/
+
+
+!File: bigresult.h
+#define BIG_RESULT_ON_STACK 1	/* define when function results must be
+				   put on the stack; in this case, caller
+				   reserves space for it. When not defined,
+				   callee puts result in global data area and
+				   returns a pointer to it
+				*/
+
+

lang/m2/comp/code.c

@@ -30,6 +30,7 @@
 #include	"Lpars.h"
 #include	"standards.h"
 #include	"walk.h"
+#include	"bigresult.h"
 
 extern char	*long2str();
 extern char	*symbol2str();
@@ -321,11 +322,12 @@ CodeCall(nd)
 
 	assert(IsProc(left));
 
-	if (result_tp = ResultType(left->nd_type)) {
-		if (TooBigForReturnArea(result_tp)) {
-			C_asp(-WA(result_tp->tp_size));
-		}
+	result_tp = ResultType(left->nd_type);
+#ifdef BIG_RESULT_ON_STACK
+	if (result_tp && TooBigForReturnArea(result_tp)) {
+		C_asp(-WA(result_tp->tp_size));
 	}
+#endif
 
 	if (nd->nd_right) {
 		CodeParameters(ParamList(left->nd_type), nd->nd_right);
@@ -356,9 +358,14 @@ CodeCall(nd)
 	}
 	C_asp(left->nd_type->prc_nbpar);
 	if (result_tp) {
+		arith sz = WA(result_tp->tp_size);
 		if (TooBigForReturnArea(result_tp)) {
+#ifndef BIG_RESULT_ON_STACK
+			C_lfr(pointer_size);
+			C_loi(sz);
+#endif
 		}
-		else	C_lfr(WA(result_tp->tp_size));
+		else	C_lfr(sz);
 	}
 	DoFilename(needs_fn);
 	DoLineno(nd);

lang/m2/comp/type.H

@@ -226,7 +226,13 @@ extern t_type
 					(tpx))
 #define	IsConstructed(tpx)	((tpx)->tp_fund & T_CONSTRUCTED)
 #define	TooBigForReturnArea(tpx) ((tpx)->tp_size > ret_area_size)
+
+#include "bigparam.h"
+#ifdef PASS_BIG_VAL_AS_VAR
 #define IsBigParamTp(tpx)	((tpx)->tp_size > double_size)
+#else
+#define IsBigParamTp(tpx)	(0)
+#endif PASS_BIG_VAL_AS_VAR
 
 extern long full_mask[];
 extern long max_int[];

lang/m2/comp/walk.c

@@ -38,6 +38,7 @@
 #include	"walk.h"
 #include	"misc.h"
 #include	"warning.h"
+#include	"bigresult.h"
 
 extern arith		NewPtr();
 extern arith		NewInt();
@@ -234,7 +235,7 @@ WalkProcedure(procedure)
 	register t_scope *procscope = procedure->prc_vis->sc_scope;
 	register t_type *tp;
 	register t_param *param;
-	int too_big = 0;		/* returnsize larger than returnarea */
+	label too_big = 0;		/* returnsize larger than returnarea */
 	arith StackAdjustment = 0;	/* space for conformant arrays */
 	arith retsav = 0;		/* temporary space for return value */
 	arith func_res_size = 0;
@@ -254,11 +255,25 @@ WalkProcedure(procedure)
 	if (tp) {
 		func_res_size = WA(tp->tp_size);
 		if (TooBigForReturnArea(tp)) {
-			/* The result type of this procedure is constructed.
+#ifdef BIG_RESULT_ON_STACK
+			/* The result type of this procedure is too big.
 			   The caller will have reserved space on its stack,
 			   above the parameters, to store the result.
 			*/
 			too_big = 1;
+#else
+			/* The result type of this procedure is too big.
+			   The actual procedure will return a pointer to a
+			   global data area in which the function result is
+			   stored.
+			   Notice that this makes the code non-reentrant.
+			   Here, we create the data area for the function
+			   result.
+			*/
+			too_big = ++data_label;
+			C_df_dlb(too_big);
+			C_bss_cst(func_res_size, (arith)0, 0);
+#endif BIG_RESULT_ON_STACK
 		}
 	}
 
@@ -378,7 +393,11 @@ WalkProcedure(procedure)
 		/* Fill the data area reserved for the function result
 		   with the result
 		*/
+#ifdef BIG_RESULT_ON_STACK
 		C_lal(procedure->df_type->prc_nbpar);
+#else
+		c_lae_dlb(too_big);
+#endif BIG_RESULT_ON_STACK
 		C_sti(func_res_size);
 		if (StackAdjustment) {
 			/* Remove copies of conformant arrays
@@ -386,7 +405,12 @@ WalkProcedure(procedure)
 			LOL(StackAdjustment, pointer_size);
 			C_str((arith) 1);
 		}
+#ifdef BIG_RESULT_ON_STACK
 		func_res_size = 0;
+#else
+		c_lae_dlb(too_big);
+		func_res_size = pointer_size;
+#endif BIG_RESULT_ON_STACK
 	}
 	else if (StackAdjustment) {
 		/* First save the function result in a safe place.
@@ -406,8 +430,11 @@ WalkProcedure(procedure)
 	C_ret(func_res_size);
 	C_beginpart(partno2);
 	C_pro(procscope->sc_name, -procscope->sc_off);
-	C_ms_par(procedure->df_type->prc_nbpar +
-		 (too_big ? func_res_size : 0));
+	C_ms_par(procedure->df_type->prc_nbpar
+#ifdef BIG_RESULT_ON_STACK
+		+ (too_big ? func_res_size : 0)
+#endif
+		);
 	if (! options['n']) WalkDefList(procscope->sc_def, RegisterMessage);
 	C_endpart(partno2);
 	C_end(-procscope->sc_off);
@@ -974,9 +1001,11 @@ UseWarnings(df)
 		warning = "never used/assigned";
 		break;
 	case D_USED|D_VARPAR:
+#ifdef PASS_BIG_VAL_AS_VAR
 		if (df->df_type->tp_fund != T_EQUAL) {
 			warning = "never assigned, could be value parameter";
 		}
+#endif
 		break;
 	case D_USED:
 		warning = "never assigned";