Merge pull request #636 from steveicarus/string-special-characters

String special characters

ivtest/ivltests/sv_string7.v

@@ -0,0 +1,45 @@
+
+module main;
+
+   string foo;
+   int 	  error_count;
+
+   task check_char(input int idx, input [7:0] val);
+      if (foo[idx] !== val) begin
+	 $display("FAILED: foo[%0d]==%02h, expecting %02h",
+		  idx, foo[idx], val);
+	 error_count = error_count+1;
+      end
+   endtask // check_char
+   
+   initial begin
+      // These are the special charasters in strings as defined by
+      // IEEE Std 1800-2017: 5.9.1 Special characters in strings.
+      // The string assignment is governed by:
+      // IEEE Std 1800-2017: 6.16 String data type
+      foo = "abc\n\t\\\"\v\f\a\001\002\x03\x04";
+      error_count = 0;
+
+      check_char(0, 8'h61); // 'a'
+      check_char(1, 8'h62); // 'b'
+      check_char(2, 8'h63); // 'c'
+      check_char(3, 8'h0a); // '\n'
+      check_char(4, 8'h09); // '\t'
+      check_char(5, 8'h5c); // '\\'
+      check_char(6, 8'h22); // '\"'
+      check_char(7, 8'h0b); // '\v'
+      check_char(8, 8'h0c); // '\f'
+      check_char(9, 8'h07); // '\a'
+      check_char(10, 8'h01); // '\001'
+      check_char(11, 8'h02); // '\002'
+      check_char(12, 8'h03); // '\x03'
+      check_char(13, 8'h04); // '\x04'
+
+      if (foo.len() !== 14) begin
+	 $display("FAILED: foo.len() == %0d, should be 14", foo.len());
+	 error_count = error_count+1;
+      end
+
+      if (error_count == 0) $display("PASSED");
+   end
+endmodule // main

ivtest/ivltests/sv_string7b.v

@@ -0,0 +1,46 @@
+
+module main;
+
+   string foo;
+   int 	  error_count;
+
+   task check_char(input int idx, input [7:0] val);
+      if (foo[idx] !== val) begin
+	 $display("FAILED: foo[%0d]==%02h, expecting %02h",
+		  idx, foo[idx], val);
+	 error_count = error_count+1;
+      end
+   endtask // check_char
+   
+   initial begin
+      // These are the special charasters in strings as defined by
+      // IEEE Std 1800-2017: 5.9.1 Special characters in strings.
+      // The string assignment is governed by:
+      // IEEE Std 1800-2017: 6.16 String data type
+      foo = "abc";
+      foo = {foo, "\n\t\\\"\v\f\a\001\002\x03\x04"};
+      error_count = 0;
+
+      check_char(0, 8'h61); // 'a'
+      check_char(1, 8'h62); // 'b'
+      check_char(2, 8'h63); // 'c'
+      check_char(3, 8'h0a); // '\n'
+      check_char(4, 8'h09); // '\t'
+      check_char(5, 8'h5c); // '\\'
+      check_char(6, 8'h22); // '\"'
+      check_char(7, 8'h0b); // '\v'
+      check_char(8, 8'h0c); // '\f'
+      check_char(9, 8'h07); // '\a'
+      check_char(10, 8'h01); // '\001'
+      check_char(11, 8'h02); // '\002'
+      check_char(12, 8'h03); // '\x03'
+      check_char(13, 8'h04); // '\x04'
+
+      if (foo.len() !== 14) begin
+	 $display("FAILED: foo.len() == %0d, should be 14", foo.len());
+	 error_count = error_count+1;
+      end
+
+      if (error_count == 0) $display("PASSED");
+   end
+endmodule // main

ivtest/regress-sv.list

@@ -531,6 +531,8 @@ sv_string3		normal,-g2009		ivltests
 sv_string4		normal,-g2009		ivltests
 sv_string5		normal,-g2009		ivltests
 sv_string6		normal,-g2009		ivltests
+sv_string7		normal,-g2009		ivltests
+sv_string7b		normal,-g2009		ivltests
 sv_timeunit_prec1	normal,-g2005-sv	ivltests
 sv_timeunit_prec2	normal,-g2009		ivltests
 sv_timeunit_prec3a	normal,-g2005-sv	ivltests gold=sv_timeunit_prec3a.gold

verinum.cc

@@ -81,6 +81,18 @@ static string process_verilog_string_quotes(const string&str)
 			res = res + '\t';
 			idx += 1;
 			break;
+		      case 'v':
+			res = res + '\v';
+			idx += 1;
+			break;
+		      case 'f':
+			res = res + '\f';
+			idx += 1;
+			break;
+		      case 'a':
+			res = res + '\a';
+			idx += 1;
+			break;
 		      case '0':
 		      case '1':
 		      case '2':
@@ -101,6 +113,27 @@ static string process_verilog_string_quotes(const string&str)
 			    res = res + byte_val;
 			    break;
 		      }
+		      case 'x': {
+			    char byte_val = 0;
+			    int odx = 1;
+			    while (odx < 3 && idx+odx < str_len) {
+				  if (str[idx+odx] >= '0' && str[idx+odx] <= '9') {
+					byte_val = 16*byte_val + str[idx+odx]-'0';
+					odx += 1;
+				  } else if  (str[idx+odx] >= 'a' && str[idx+odx] <= 'f') {
+					byte_val = 16*byte_val + str[idx+odx]-'a'+10;
+					odx += 1;
+				  } else if  (str[idx+odx] >= 'A' && str[idx+odx] <= 'F') {
+					byte_val = 16*byte_val + str[idx+odx]-'A'+10;
+					odx += 1;
+				  } else {
+					break;
+				  }
+			    }
+			    idx += odx;
+			    res = res + byte_val;
+			    break;
+		      }
 		      default:
 			res = res + str[idx];
 			idx += 1;

vvp/vthread.cc

@@ -364,6 +364,56 @@ void vthread_s::debug_dump(ostream&fd, const char*label)
       fd << "**** Done ****" << endl;
 }
 
+/*
+ * This function converts the text format of the string by interpreting
+ * any octal characters (\nnn) to their single byte value. We do this here
+ * because the text value in the vvp_code_t is stored as a C string. This
+ * converts it to a C++ string that can hold binary values. We only have
+ * to handle the octal escapes because the main compiler takes care of all
+ * the other string special characters and normalizes the strings to use
+ * only this format.
+ */
+static string filter_string(const char*text)
+{
+      vector<char> tmp (strlen(text)+1);
+      size_t dst = 0;
+      for (const char*ptr = text ; *ptr ; ptr += 1) {
+	    // Not an escape? Move on.
+	    if (*ptr != '\\') {
+		  tmp[dst++] = *ptr;
+		  continue;
+	    }
+
+	    // Now we know that *ptr is pointing to a \ character and we
+	    // have an octal sequence coming up. Advance the ptr and start
+	    // processing octal digits.
+	    ptr += 1;
+	    if (*ptr == 0)
+		  break;
+
+	    char byte = 0;
+	    int cnt = 3;
+	    while (*ptr && cnt > 0 && *ptr >= '0' && *ptr <= '7') {
+		  byte *= 8;
+		  byte += *ptr - '0';
+		  cnt -= 1;
+		  ptr += 1;
+	    }
+	    tmp[dst++] = byte;
+
+	    // After the while loop above, the ptr points to the next character,
+	    // but the for-loop condition is assuming that ptr points to the last
+	    // character, since it has the ptr+=1.
+	    ptr -= 1;
+      }
+
+      // Put a nul byte at the end of the built up string, but really we are
+      // using the known length in the string constructor.
+      tmp[dst] = 0;
+      string res (&tmp[0], dst);
+      return res;
+}
+
 static void do_join(vthread_t thr, vthread_t child);
 
 __vpiScope* vthread_scope(struct vthread_s*thr)
@@ -2264,7 +2314,7 @@ bool of_CONCAT_STR(vthread_t thr, vvp_code_t)
 bool of_CONCATI_STR(vthread_t thr, vvp_code_t cp)
 {
       const char*text = cp->text;
-      thr->peek_str(0).append(text);
+      thr->peek_str(0).append(filter_string(text));
       return true;
 }
 
@@ -5012,7 +5062,7 @@ bool of_PUSHI_REAL(vthread_t thr, vvp_code_t cp)
 bool of_PUSHI_STR(vthread_t thr, vvp_code_t cp)
 {
       const char*text = cp->text;
-      thr->push_str(string(text));
+      thr->push_str(filter_string(text));
       return true;
 }