Add a -Wselect-range warning class.

This patch adds support for a -Wselect-range warning class to the
driver and ivl programs. This is part of -Wall. The actual checks
will be added in a later patch.

Cherry-picked from e576e1eb2c

compiler.h

@@ -82,6 +82,9 @@ extern bool warn_timescale;
 /* Warn about legal but questionable module port bindings. */
 extern bool warn_portbinding;
 
+/* Warn about constant out of bound selects. */
+extern bool warn_ob_select;
+
 /* Warn about structures that may have infinite loops. */
 extern bool warn_inf_loop;
 

driver/iverilog.man

@@ -254,7 +254,8 @@ after a \fB-Wall\fP argument to suppress isolated warning types.
 
 .TP 8
 .B all
-This enables all supported warning categories.
+This enables the implicit, portbind, select-range and timescale warning
+categories.
 
 .TP 8
 .B implicit
@@ -268,6 +269,12 @@ This enables warnings for ports of module instantiations that are not
 connected but probably should be. Dangling input ports, for example,
 will generate a warning.
 
+.TP 8
+.B select-range
+This enables warnings for constant out of bound selects. This includes
+partial or fully out of bound selects as well as a select using 'bx as
+an index.
+
 .TP 8
 .B timescale
 This enables warnings for inconsistent use of the timescale

driver/main.c

@@ -469,6 +469,7 @@ static void process_warning_switch(const char*name)
       if (strcmp(name,"all") == 0) {
 	    process_warning_switch("implicit");
 	    process_warning_switch("portbind");
+	    process_warning_switch("select-range");
 	    process_warning_switch("timescale");
       } else if (strcmp(name,"implicit") == 0) {
 	    if (! strchr(warning_flags, 'i'))
@@ -476,6 +477,9 @@ static void process_warning_switch(const char*name)
       } else if (strcmp(name,"portbind") == 0) {
 	    if (! strchr(warning_flags, 'p'))
 		  strcat(warning_flags, "p");
+      } else if (strcmp(name,"select-range") == 0) {
+	    if (! strchr(warning_flags, 's'))
+		  strcat(warning_flags, "s");
       } else if (strcmp(name,"timescale") == 0) {
 	    if (! strchr(warning_flags, 't'))
 		  strcat(warning_flags, "t");
@@ -496,6 +500,12 @@ static void process_warning_switch(const char*name)
 		  cp[0] = cp[1];
 		  cp += 1;
 	    }
+      } else if (strcmp(name,"no-select-range") == 0) {
+	    char*cp = strchr(warning_flags, 's');
+	    if (cp) while (*cp) {
+		  cp[0] = cp[1];
+		  cp += 1;
+	    }
       } else if (strcmp(name,"no-timescale") == 0) {
 	    char*cp = strchr(warning_flags, 't');
 	    if (cp) while (*cp) {

main.cc

@@ -115,6 +115,7 @@ bool warn_implicit  = false;
 bool warn_timescale = false;
 bool warn_portbinding = false;
 bool warn_inf_loop = false;
+bool warn_ob_select = false;
 
 bool error_implicit = false;
 
@@ -491,6 +492,9 @@ static void read_iconfig_file(const char*ipath)
 		      case 'l':
 			warn_inf_loop = true;
 			break;
+		      case 's':
+			warn_ob_select = true;
+			break;
 		      case 'p':
 			warn_portbinding = true;
 			break;