Detect and warn about anachronistic use of begin/end in generate.

Verilog-2001 only allows a single generate item within a generate-
endgenerate region, but allowed one to collect generate schemes with
begin/end blocks. Verilog-2005 cleaned up that mess, and it is the
2005 syntax that Icarus Verilog implements. This patch detects the
anachronistic use of begin/end within the generate region, ignores
the begin/end words, and prints a warning that the user is using an
obsolete syntax.

parse.y

@@ -2200,6 +2200,15 @@ module_item
     K_endcase
       { pform_endgenerate(); }
 
+  /* Handle some anachronistic syntax cases. */
+  | K_generate K_begin module_item_list_opt K_end K_endgenerate
+      { /* Detect and warn about anachronistic begin/end use */
+	if (generation_flag > GN_VER2001) {
+	      warn_count += 1;
+	      cerr << @2 << ": warning: Anachronistic use of begin/end to surround generate schemes." << endl;
+	}
+      }
+
   /* specify blocks are parsed but ignored. */
 
 	| K_specify K_endspecify

parse_misc.cc

@@ -30,6 +30,15 @@ unsigned error_count = 0;
 unsigned warn_count = 0;
 unsigned long based_size = 0;
 
+std::ostream& operator << (std::ostream&o, const YYLTYPE&loc)
+{
+      if (loc.text)
+	    o << loc.text << ":";
+      o << loc.first_line;
+      return o;
+}
+
+
 void VLerror(const char*msg)
 {
       error_count += 1;
@@ -39,20 +48,14 @@ void VLerror(const char*msg)
 void VLerror(const YYLTYPE&loc, const char*msg)
 {
       error_count += 1;
-      if (loc.text)
-	    cerr << loc.text << ":";
-
-      cerr << loc.first_line << ": " << msg << endl;
+      cerr << loc << ": " << msg << endl;
       based_size = 0; /* Clear the base information if we have an error. */
 }
 
 void yywarn(const YYLTYPE&loc, const char*msg)
 {
       warn_count += 1;
-      if (loc.text)
-	    cerr << loc.text << ":";
-
-      cerr << loc.first_line << ": warning: " << msg << endl;
+      cerr << loc << ": warning: " << msg << endl;
 }
 
 int VLwrap()

parse_misc.h

@@ -23,6 +23,7 @@
 #endif
 
 # include  <list>
+# include  <ostream>
 # include  "compiler.h"
 # include  "pform.h"
 
@@ -62,6 +63,8 @@ extern void VLerror(const YYLTYPE&loc, const char*msg);
 #define yywarn VLwarn
 extern void VLwarn(const YYLTYPE&loc, const char*msg);
 
+extern ostream& operator << (ostream&, const YYLTYPE&loc);
+
 extern unsigned error_count, warn_count;
 extern unsigned long based_size;