Support ${...} and $(...) env variables in .vc files

Changes

@@ -7,6 +7,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ***  Add --trace-max-width and --trace-max-array, bug 319.  [Alex Solomatnikov]
 
+**** Support ${...} and $(...) env vars in .vc files.  [by Stefan Wallentowitz]
+
 **** Support $bits(data_type), bug327.  [Alex Solomatnikov]
 
 **** Support loop unrolling on width mismatches, bug 333. [Joe Eiler]

bin/verilator

@@ -536,14 +536,18 @@ the command line that implement the main loop for your simulation.
 
 Read the specified file, and act as if all text inside it was specified as
 command line parameters.  Any relative paths are relative to the directory
-containing the specified file.  Note -F is fairly standard across Verilog
-tools.
+containing the specified file.  See also -f. Note -F is fairly standard
+across Verilog tools.
 
 =item -f I<file>
 
 Read the specified file, and act as if all text inside it was specified as
 command line parameters.  Any relative paths are relative to the current
-directory.  Note -f is fairly standard across Verilog tools.
+directory.  See also -F. Note -f is fairly standard across Verilog tools.
+
+The file may contain // comments which are ignored to the end of the line.
+Any $VAR, $(VAR), or ${VAR} will be replaced with the specified environment
+variable.
 
 =item --gdbbt
 

src/V3Options.cpp

@@ -194,18 +194,33 @@ string V3Options::filenameNonExt (const string& filename) {
 
 string V3Options::filenameSubstitute (const string& filename) {
     string out;
+    enum { NONE, PAREN, CURLY } brackets = NONE;
     for (string::size_type pos = 0; pos < filename.length(); ++pos) {
-	if (filename[pos] == '$') {
+        if ((filename[pos] == '$') && (pos+1 < filename.length())) {
+	    switch (filename[pos+1]) {
+	        case '{': brackets = CURLY; break;
+	        case '(': brackets = PAREN; break;
+	        default: brackets = NONE; break;
+	    }
+	    if (brackets != NONE) pos = pos+1;
 	    string::size_type endpos = pos+1;
-	    while ((endpos+1) < filename.length()
-		   && (isalnum(filename[endpos+1]) || filename[endpos+1]=='_'))
+	    while (((endpos+1) < filename.length()) &&
+		   (((brackets==NONE) && (isalnum(filename[endpos+1]) || filename[endpos+1]=='_')) ||
+		    ((brackets==CURLY) && (filename[endpos+1]!='}')) ||
+		    ((brackets==PAREN) && (filename[endpos+1]!=')'))))
 		++endpos;
+	    // Catch bracket errors
+	    if (((brackets==CURLY) && (filename[endpos+1]!='}')) ||
+		((brackets==PAREN) && (filename[endpos+1]!=')'))) {
+	      v3fatal("Unmatched brackets in variable substitution in file: "+filename);
+	    }
 	    string envvar = filename.substr(pos+1,endpos-pos);
 	    const char* envvalue = NULL;
 	    if (envvar != "") envvalue = getenv(envvar.c_str());
 	    if (envvalue) {
 		out += envvalue;
-		pos = endpos;
+		if (brackets==NONE) pos = endpos;
+		else pos = endpos+1;
 	    } else {
 		out += filename[pos];  // *pos == '$'
 	    }
@@ -214,6 +229,7 @@ string V3Options::filenameSubstitute (const string& filename) {
 	}
     }
     return out;
+
 }
 
 bool V3Options::filenameIsRel(const string& filename) {

test_regress/t/t_flag_f.vc

@@ -1,6 +1,6 @@
 // Test that environment substitutions work
 -f $VERILATOR_ROOT/test_regress/t/t_flag_f__2.vc
-// Env var with .v file
-$VERILATOR_ROOT/test_regress/t/t_flag_f__3.v
+// Env var with .v file, and parens
+${VERILATOR_ROOT}/test_regress/t/t_flag_f__3.v
 // Test -f
 -F $VERILATOR_ROOT/test_regress/t/tsub/t_flag_f_tsub.vc