a68: parser: dynamic stack usage in serial clauses

Signed-off-by: Jose E. Marchesi <jemarch@gnu.org> gcc/ChangeLog * algol68/a68-parser-serial-dsa.cc: New file.
2026-05-06 14:59:39 +02:00 · 2025-10-11 19:50:49 +02:00
parent ef7c6104e5
commit 803189d932
1 changed files with 114 additions and 0 deletions
--- a/gcc/algol68/a68-parser-serial-dsa.cc
+++ b/gcc/algol68/a68-parser-serial-dsa.cc
@@ -0,0 +1,114 @@
+/* Check dynamic stack usage in serial clauses.
+   Copyright (C) 2025 Jose E. Marchesi.
+
+   Written by Jose E. Marchesi.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   GCC is distributed in the hope that it will be useful, but WITHOUT
+   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+   License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This file implements a phase that determines what serial clauses contain
+   phrases whose elaboration may involve dynamic stack allocation.  It
+   annotates the SERIAL_CLAUSE parse nodes by setting the DYNAMIC_STACK_ALLOCS
+   flag.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "options.h"
+
+#include "a68.h"
+
+/* Uncomment the following line for debugging traces.  */
+/* #define SERIAL_DSA_DEBUG */
+
+static void
+serial_dsa_check_serial_clause (NODE_T *p, bool *dsa)
+{
+  for (; p != NO_NODE; FORWARD (p))
+    {
+      if (IS (p, GENERATOR))
+	{
+	  /* LOC generators always result in dyamic stack allocation regardless
+	     of the mode of the allocated value.  */
+	  if (IS (SUB (p), LOC_SYMBOL))
+	    {
+#ifdef SERIAL_DSA_DEBUG
+	      fprintf (stderr, "serial_dsa: %s:%d: loc generator implies DSA\n",
+		       FILENAME (LINE (INFO (p))),
+		       LINE_NUMBER (p));
+#endif
+	      *dsa = true;
+	      return;
+	    }
+	}
+      else if (IS (p, DEFINING_IDENTIFIER))
+	{
+	  /* Variable declarations of values with sample loc generators will
+	     result in dynamic stack allocation.
+
+	     Note that label declarations do no have a mode, so we have to
+	     check for MOID (p).  */
+
+	  if (MOID (p) != NO_MOID && IS_REF (MOID (p)))
+	    {
+	      bool heap = HEAP (TAX (p)) == HEAP_SYMBOL;
+	      if (HAS_ROWS (SUB (MOID (p))) && !heap)
+		{
+#ifdef SERIAL_DSA_DEBUG		  
+		  fprintf (stderr,
+			   "serial_dsa: %s:%d: defining identifier %s implies DSA\n",
+			   FILENAME (LINE (INFO (p))),
+			   LINE_NUMBER (p),
+			   NSYMBOL (p));
+#endif
+		  *dsa = true;
+		  return;
+		}
+	    }
+	}
+      else
+	{
+	  /* Inner serial clauses will take care of their own.  Code in routine
+	     texts will not impact the stack of the containing serial
+	     clause.  */
+	  if (!IS (p, SERIAL_CLAUSE) && !IS (p, ROUTINE_TEXT))
+	    serial_dsa_check_serial_clause (SUB (p), dsa);
+	}
+    }
+}
+
+void
+a68_serial_dsa (NODE_T *p)
+{
+  for (; p != NO_NODE; FORWARD (p))
+    {
+      a68_serial_dsa (SUB (p));
+      if (IS (p, SERIAL_CLAUSE))
+	{
+	  bool dsa = false;
+	  serial_dsa_check_serial_clause (SUB (p), &dsa);
+	  DYNAMIC_STACK_ALLOCS (p) = dsa;
+#ifdef SERIAL_DSA_DEBUG
+	  if (dsa)
+	    {
+	      fprintf (stderr, "serial_dsa: %s:%d: marking serial clause %p as DSA\n",
+		       FILENAME (LINE (INFO (p))),
+		       LINE_NUMBER (p),
+		       (void *) p);
+	    }
+	  
+#endif
+	}
+    }
+}