[patch] Changes to allow extensions to operator set (installment 1)

[Paul Hilfinger <hilfingr at gnat dot com>]

I have committed the following patch, part of a larger one previously
submitted for approval.  This part Andrew approved a while ago and asked
to have submitted separately.

Paul Hilfinger
ACT, Inc.

ChangeLog:
2003-09-23  Paul N. Hilfinger  <hilfingr@nile.gnat.com>

	* parser-defs.h (operator_length): Declare.
	
	* parse.c (length_of_subexp): Use operator_length to get operator
	lengths and arities for operators.
	Move most code to new operator_length function.
	(operator_length): New function absorbing most code from 
	length_of_subexp.
	(prefixify_subexp): Remove large case and use operator_length instead.
	(parse_exp_1): Use renamings:
	dump_prefix_expression => dump_raw_expression and 
	dump_postfix_expression => dump_prefix_expression.
	
	* expression.h (dump_prefix_expression): Rename to ...
	(dump_raw_expression): New name.
	(dump_postfix_expression): Rename to ...
	(dump_prefix_expression): New name.
	
	* expprint.c (dump_subexp): Make global.  Add comment.
	Move most existing code to dump_subexp_body.
	(dump_subexp_body): New function.
	(dump_prefix_expression): Rename to dump_raw_expression.
	Remove attempt to print the expression via print_expression: it can't 
	work before the expression is prefixified.
	(dump_raw_expression): Renamed from dump_prefix_expression.
	(dump_postfix_expression): Rename to dump_prefix_expression, since 
	that's what it does.
	Remove 'note' parameter, since this routine must be used on 
	prefixified expression.
	(dump_prefix_expression): Renamed from dump_postfix_expression.
	
Index: gdb/expprint.c
===================================================================
RCS file: /cvs/src/src/gdb/expprint.c,v
retrieving revision 1.18
diff -u -p -r1.18 expprint.c
--- gdb/expprint.c	9 Sep 2003 08:05:42 -0000	1.18
+++ gdb/expprint.c	24 Sep 2003 07:44:48 -0000
@@ -548,6 +548,7 @@ op_string (enum exp_opcode op)
    form.  */
 
 static char *op_name (int opcode);
+static int dump_subexp_body (struct expression *exp, struct ui_file *, int);
 
 static char *
 op_name (int opcode)
@@ -737,8 +738,8 @@ op_name (int opcode)
 }
 
 void
-dump_prefix_expression (struct expression *exp, struct ui_file *stream,
-			char *note)
+dump_raw_expression (struct expression *exp, struct ui_file *stream,
+		     char *note)
 {
   int elt;
   char *opcode_name;
@@ -747,11 +748,6 @@ dump_prefix_expression (struct expressio
 
   fprintf_filtered (stream, "Dump of expression @ ");
   gdb_print_host_address (exp, stream);
-  fprintf_filtered (stream, ", %s:\nExpression: `", note);
-  if (exp->elts[0].opcode != OP_TYPE)
-    print_expression (exp, stream);
-  else
-    fprintf_filtered (stream, "Type printing not yet supported....");
   fprintf_filtered (stream, "'\n\tLanguage %s, %d elements, %ld bytes each.\n",
 		    exp->language_defn->la_name, exp->nelts,
 		    (long) sizeof (union exp_element));
@@ -778,10 +774,11 @@ dump_prefix_expression (struct expressio
     }
 }
 
-static int dump_subexp (struct expression *exp, struct ui_file *stream,
-			int elt);
+/* Dump the subexpression of prefix expression EXP whose operator is at
+   position ELT onto STREAM.  Returns the position of the next 
+   subexpression in EXP.  */
 
-static int
+int
 dump_subexp (struct expression *exp, struct ui_file *stream, int elt)
 {
   static int indent = 0;
@@ -796,7 +793,23 @@ dump_subexp (struct expression *exp, str
 
   fprintf_filtered (stream, "%-20s  ", op_name (exp->elts[elt].opcode));
 
-  switch (exp->elts[elt++].opcode)
+  elt = dump_subexp_body (exp, stream, elt);
+
+  indent -= 2;
+
+  return elt;
+}
+
+/* Dump the operands of prefix expression EXP whose opcode is at
+   position ELT onto STREAM.  Returns the position of the next 
+   subexpression in EXP.  */
+
+static int
+dump_subexp_body (struct expression *exp, struct ui_file *stream, int elt)
+{
+  int opcode = exp->elts[elt++].opcode;
+
+  switch (opcode)
     {
     case TERNOP_COND:
     case TERNOP_SLICE:
@@ -914,7 +927,7 @@ dump_subexp (struct expression *exp, str
       break;
     case OP_FUNCALL:
       {
-	int nargs;
+	int i, nargs;
 
 	nargs = longest_to_int (exp->elts[elt].longconst);
 
@@ -1006,20 +1019,17 @@ dump_subexp (struct expression *exp, str
       fprintf_filtered (stream, "Unknown format");
     }
 
-  indent -= 2;
-
   return elt;
 }
 
 void
-dump_postfix_expression (struct expression *exp, struct ui_file *stream,
-			 char *note)
+dump_prefix_expression (struct expression *exp, struct ui_file *stream)
 {
   int elt;
 
   fprintf_filtered (stream, "Dump of expression @ ");
   gdb_print_host_address (exp, stream);
-  fprintf_filtered (stream, ", %s:\nExpression: `", note);
+  fputs_filtered (", after conversion to prefix form:\nExpression: `", stream);
   if (exp->elts[0].opcode != OP_TYPE)
     print_expression (exp, stream);
   else
Index: gdb/expression.h
===================================================================
RCS file: /cvs/src/src/gdb/expression.h,v
retrieving revision 1.11
diff -u -p -r1.11 expression.h
--- gdb/expression.h	18 Mar 2003 22:03:28 -0000	1.11
+++ gdb/expression.h	24 Sep 2003 07:44:48 -0000
@@ -393,11 +393,7 @@ extern void print_expression (struct exp
 
 extern char *op_string (enum exp_opcode);
 
-extern void dump_prefix_expression (struct expression *,
-				    struct ui_file *,
-				    char *);
-extern void dump_postfix_expression (struct expression *,
-				     struct ui_file *,
-				     char *);
+extern void dump_raw_expression (struct expression *, struct ui_file *, char *);
+extern void dump_prefix_expression (struct expression *, struct ui_file *);
 
 #endif /* !defined (EXPRESSION_H) */
Index: gdb/parse.c
===================================================================
RCS file: /cvs/src/src/gdb/parse.c,v
retrieving revision 1.36
diff -u -p -r1.36 parse.c
--- gdb/parse.c	9 Sep 2003 08:05:42 -0000	1.36
+++ gdb/parse.c	24 Sep 2003 07:44:49 -0000
@@ -784,18 +784,38 @@ prefixify_expression (struct expression 
   prefixify_subexp (temp, expr, inpos, outpos);
 }
 
-/* Return the number of exp_elements in the subexpression of EXPR
-   whose last exp_element is at index ENDPOS - 1 in EXPR.  */
+/* Return the number of exp_elements in the postfix subexpression 
+   of EXPR whose operator is at index ENDPOS - 1 in EXPR.  */
 
 int
 length_of_subexp (struct expression *expr, int endpos)
 {
+  int oplen, args, i;
+
+  operator_length (expr, endpos, &oplen, &args);
+
+  while (args > 0)
+    {
+      oplen += length_of_subexp (expr, endpos - oplen);
+      args--;
+    }
+
+  return oplen;
+}
+
+/* Sets *OPLENP to the length of the operator whose (last) index is 
+   ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
+   operator takes.  */
+
+void
+operator_length (struct expression *expr, int endpos, int *oplenp, int *argsp)
+{
   int oplen = 1;
   int args = 0;
   int i;
 
   if (endpos < 1)
-    error ("?error in length_of_subexp");
+    error ("?error in operator_length");
 
   i = (int) expr->elts[endpos - 1].opcode;
 
@@ -916,13 +936,8 @@ length_of_subexp (struct expression *exp
       args = 1 + (i < (int) BINOP_END);
     }
 
-  while (args > 0)
-    {
-      oplen += length_of_subexp (expr, endpos - oplen);
-      args--;
-    }
-
-  return oplen;
+  *oplenp = oplen;
+  *argsp = args;
 }
 
 /* Copy the subexpression ending just before index INEND in INEXPR
@@ -933,132 +948,13 @@ static void
 prefixify_subexp (struct expression *inexpr,
 		  struct expression *outexpr, int inend, int outbeg)
 {
-  int oplen = 1;
-  int args = 0;
+  int oplen;
+  int args;
   int i;
   int *arglens;
   enum exp_opcode opcode;
 
-  /* Compute how long the last operation is (in OPLEN),
-     and also how many preceding subexpressions serve as
-     arguments for it (in ARGS).  */
-
-  opcode = inexpr->elts[inend - 1].opcode;
-  switch (opcode)
-    {
-      /* C++  */
-    case OP_SCOPE:
-      oplen = longest_to_int (inexpr->elts[inend - 2].longconst);
-      oplen = 5 + BYTES_TO_EXP_ELEM (oplen + 1);
-      break;
-
-    case OP_LONG:
-    case OP_DOUBLE:
-    case OP_VAR_VALUE:
-      oplen = 4;
-      break;
-
-    case OP_TYPE:
-    case OP_BOOL:
-    case OP_LAST:
-    case OP_REGISTER:
-    case OP_INTERNALVAR:
-      oplen = 3;
-      break;
-
-    case OP_COMPLEX:
-      oplen = 1;
-      args = 2;
-      break;
-
-    case OP_FUNCALL:
-    case OP_F77_UNDETERMINED_ARGLIST:
-      oplen = 3;
-      args = 1 + longest_to_int (inexpr->elts[inend - 2].longconst);
-      break;
-
-    case OP_OBJC_MSGCALL:	/* Objective C message (method) call */
-      oplen = 4;
-      args = 1 + longest_to_int (inexpr->elts[inend - 2].longconst);
-      break;
-
-    case UNOP_MIN:
-    case UNOP_MAX:
-      oplen = 3;
-      break;
-
-    case UNOP_CAST:
-    case UNOP_MEMVAL:
-      oplen = 3;
-      args = 1;
-      break;
-
-    case UNOP_ABS:
-    case UNOP_CAP:
-    case UNOP_CHR:
-    case UNOP_FLOAT:
-    case UNOP_HIGH:
-    case UNOP_ODD:
-    case UNOP_ORD:
-    case UNOP_TRUNC:
-      oplen = 1;
-      args = 1;
-      break;
-
-    case STRUCTOP_STRUCT:
-    case STRUCTOP_PTR:
-    case OP_LABELED:
-      args = 1;
-      /* fall through */
-    case OP_M2_STRING:
-    case OP_STRING:
-    case OP_OBJC_NSSTRING:	/* Objective C Foundation Class NSString constant */
-    case OP_OBJC_SELECTOR:	/* Objective C "@selector" pseudo-op */
-    case OP_NAME:
-    case OP_EXPRSTRING:
-      oplen = longest_to_int (inexpr->elts[inend - 2].longconst);
-      oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
-      break;
-
-    case OP_BITSTRING:
-      oplen = longest_to_int (inexpr->elts[inend - 2].longconst);
-      oplen = (oplen + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
-      oplen = 4 + BYTES_TO_EXP_ELEM (oplen);
-      break;
-
-    case OP_ARRAY:
-      oplen = 4;
-      args = longest_to_int (inexpr->elts[inend - 2].longconst);
-      args -= longest_to_int (inexpr->elts[inend - 3].longconst);
-      args += 1;
-      break;
-
-    case TERNOP_COND:
-    case TERNOP_SLICE:
-    case TERNOP_SLICE_COUNT:
-      args = 3;
-      break;
-
-    case BINOP_ASSIGN_MODIFY:
-      oplen = 3;
-      args = 2;
-      break;
-
-      /* Modula-2 */
-    case MULTI_SUBSCRIPT:
-      oplen = 3;
-      args = 1 + longest_to_int (inexpr->elts[inend - 2].longconst);
-      break;
-
-      /* C++ */
-    case OP_THIS:
-    case OP_OBJC_SELF:
-      oplen = 2;
-      break;
-
-    default:
-      args = 1 + ((int) opcode < (int) BINOP_END);
-    }
+  operator_length (inexpr, inend, &oplen, &args);
 
   /* Copy the final operator itself, from the end of the input
      to the beginning of the output.  */
@@ -1156,14 +1052,13 @@ parse_exp_1 (char **stringptr, struct bl
      parser, to a prefix form. */
 
   if (expressiondebug)
-    dump_prefix_expression (expout, gdb_stdlog,
-			    "before conversion to prefix form");
+    dump_raw_expression (expout, gdb_stdlog,
+			 "before conversion to prefix form");
 
   prefixify_expression (expout);
 
   if (expressiondebug)
-    dump_postfix_expression (expout, gdb_stdlog,
-			     "after conversion to prefix form");
+    dump_prefix_expression (expout, gdb_stdlog);
 
   *stringptr = lexptr;
   return expout;
Index: gdb/parser-defs.h
===================================================================
RCS file: /cvs/src/src/gdb/parser-defs.h,v
retrieving revision 1.16
diff -u -p -r1.16 parser-defs.h
--- gdb/parser-defs.h	20 Feb 2003 00:01:06 -0000	1.16
+++ gdb/parser-defs.h	24 Sep 2003 07:44:49 -0000
@@ -159,6 +159,8 @@ extern int pop_type_int (void);
 
 extern int length_of_subexp (struct expression *, int);
 
+extern void operator_length (struct expression *, int, int *, int *);
+
 extern struct type *follow_types (struct type *);
 
 /* During parsing of a C expression, the pointer to the next character