From fd30d6c921184946896e54bdd861b71faa2b3f49 Mon Sep 17 00:00:00 2001
From: Cary R <cygcary@yahoo.com>
Date: Wed, 20 Jul 2011 20:46:27 -0700
Subject: [PATCH] Add more enumeration sequence name error checking.

This patch adds code to check for a negative or undefined value used in
an enumeration sequence name, it verifies that the count in an enumeration
sequence name is not zero and allows more decimal constant values in the
enumeration sequence name..
---
 parse.y | 81 +++++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 64 insertions(+), 17 deletions(-)

diff --git a/parse.y b/parse.y
index 9d213602e..dcae0f02a 100644
--- a/parse.y
+++ b/parse.y
@@ -197,14 +197,26 @@ static list<named_pexpr_t>* make_named_numbers(perm_string name, long first, lon
 {
       list<named_pexpr_t>*lst = new list<named_pexpr_t>;
       named_pexpr_t tmp;
-      assert(first <= last);
-      for (long idx = first ; idx <= last ; idx += 1) {
-	    ostringstream buf;
-	    buf << name.str() << idx << ends;
-	    tmp.name = lex_strings.make(buf.str());
-	    tmp.parm = val;
-	    val = 0;
-	    lst->push_back(tmp);
+	// We are counting up.
+      if (first <= last) {
+	    for (long idx = first ; idx <= last ; idx += 1) {
+		  ostringstream buf;
+		  buf << name.str() << idx << ends;
+		  tmp.name = lex_strings.make(buf.str());
+		  tmp.parm = val;
+		  val = 0;
+		  lst->push_back(tmp);
+	    }
+	// We are counting down.
+      } else {
+	    for (long idx = first ; idx >= last ; idx -= 1) {
+		  ostringstream buf;
+		  buf << name.str() << idx << ends;
+		  tmp.name = lex_strings.make(buf.str());
+		  tmp.parm = val;
+		  val = 0;
+		  lst->push_back(tmp);
+	    }
       }
       return lst;
 }
@@ -219,6 +231,28 @@ static list<named_pexpr_t>* make_named_number(perm_string name, PExpr*val =0)
       return lst;
 }
 
+static long check_enum_seq_value(const YYLTYPE&loc, verinum *arg, bool zero_ok)
+{
+      long value = 1;
+	// We can never have an undefined value in an enumeration name
+	// declaration sequence.
+      if (! arg->is_defined()) {
+	    yyerror(loc, "error: undefined value used in enum name sequence.");
+	// We can never have a negative value in an enumeration name
+	// declaration sequence.
+      } else if (arg->is_negative()) {
+	    yyerror(loc, "error: negative value used in enum name sequence.");
+      } else {
+	    value = arg->as_ulong();
+	      // We cannot have a zero enumeration name declaration count.
+	    if (! zero_ok && (value == 0)) {
+		  yyerror(loc, "error: zero count used in enum name sequence.");
+		  value = 1;
+	    }
+      }
+      return value;
+}
+
 %}
 
 %union {
@@ -388,7 +422,7 @@ static list<named_pexpr_t>* make_named_number(perm_string name, PExpr*val =0)
 %token K_zi_nd K_zi_np K_zi_zd K_zi_zp
 
 %type <flag>    from_exclude
-%type <number>  number
+%type <number>  number pos_neg_number
 %type <flag>    unsigned_signed_opt signed_unsigned_opt reg_opt
 %type <flag>    udp_reg_opt edge_operator automatic_opt
 %type <drive>   drive_strength drive_strength_opt dr_strength0 dr_strength1
@@ -777,22 +811,34 @@ enum_name_list
       }
   ;
 
+pos_neg_number
+  : number
+      { $$ = $1;
+      }
+  | '-' number
+      { verinum tmp = v_not(*($2)) + verinum(1);
+	*($2) = tmp;
+	$$ = $2;
+      }
+  ;
+
 enum_name
   : IDENTIFIER
       { perm_string name = lex_strings.make($1);
 	delete[]$1;
 	$$ = make_named_number(name);
       }
-  | IDENTIFIER '[' DEC_NUMBER ']'
+  | IDENTIFIER '[' pos_neg_number ']'
       { perm_string name = lex_strings.make($1);
-	long count = $3->as_ulong();
+	long count = check_enum_seq_value(@1, $3, false);
 	delete[]$1;
 	$$ = make_named_numbers(name, 0, count-1);
 	delete $3;
       }
-  | IDENTIFIER '[' DEC_NUMBER ':' DEC_NUMBER ']'
+  | IDENTIFIER '[' pos_neg_number ':' pos_neg_number ']'
       { perm_string name = lex_strings.make($1);
-	$$ = make_named_numbers(name, $3->as_long(), $5->as_long());
+	$$ = make_named_numbers(name, check_enum_seq_value(@1, $3, true),
+	                              check_enum_seq_value(@1, $5, true));
 	delete[]$1;
 	delete $3;
 	delete $5;
@@ -802,16 +848,17 @@ enum_name
 	delete[]$1;
 	$$ = make_named_number(name, $3);
       }
-  | IDENTIFIER '[' DEC_NUMBER ']' '=' expression
+  | IDENTIFIER '[' pos_neg_number ']' '=' expression
       { perm_string name = lex_strings.make($1);
-	long count = $3->as_ulong();
+	long count = check_enum_seq_value(@1, $3, false);
 	$$ = make_named_numbers(name, 0, count-1, $6);
 	delete[]$1;
 	delete $3;
       }
-  | IDENTIFIER '[' DEC_NUMBER ':' DEC_NUMBER ']' '=' expression
+  | IDENTIFIER '[' pos_neg_number ':' pos_neg_number ']' '=' expression
       { perm_string name = lex_strings.make($1);
-	$$ = make_named_numbers(name, $3->as_long(), $5->as_long(), $8);
+	$$ = make_named_numbers(name, check_enum_seq_value(@1, $3, true),
+	                              check_enum_seq_value(@1, $5, true), $8);
 	delete[]$1;
 	delete $3;
 	delete $5;