verilog: treat a text-macro as an identifier

Units/parser-verilog.r/systemverilog-directive.d/expected.tags

@@ -61,3 +61,4 @@ MY_DEFINE	input.sv	/^`define MY_DEFINE$/;"	d
 assert_clk	input.sv	/^`define assert_clk(arg, __clk=clk, __rst_n=rst_n) \\$/;"	d
 forSkipMacro	input.sv	/^module forSkipMacro;$/;"	m
 add_t	input.sv	/^`define add_t(f) f``_t$/;"	d	module:forSkipMacro
+`add_t	input.sv	/^    var `add_t(foo) = '0;$/;"	r	module:forSkipMacro

Units/parser-verilog.r/systemverilog-github3712.d/args.ctags

@@ -0,0 +1 @@
+--sort=no

Units/parser-verilog.r/systemverilog-github3712.d/expected.tags

@@ -0,0 +1,9 @@
+XXX_TOP	input.sv	/^`define XXX_TOP  foo_top$/;"	d
+XXX	input.sv	/^`define XXX          foo$/;"	d
+`XXX	input.sv	/^module `XXX ();$/;"	m
+add_t	input.sv	/^`define add_t(f) f``_t$/;"	d	module:`XXX
+`XXX_TOP	input.sv	/^module `XXX_TOP();$/;"	m
+foo	input.sv	/^class foo;$/;"	C
+new	input.sv	/^  function new(string name="...");$/;"	f	class:foo
+name	input.sv	/^  function new(string name="...");$/;"	p	function:foo.new
+`add_t	input.sv	/^  var `add_t(foo) = '0;$/;"	r	class:foo

Units/parser-verilog.r/systemverilog-github3712.d/input.sv

@@ -0,0 +1,25 @@
+// https://github.com/universal-ctags/ctags/issues/3712
+
+`define XXX_TOP  foo_top
+`define XXX          foo
+
+module `XXX ();
+`define add_t(f) f``_t
+endmodule
+
+module `XXX_TOP();
+  `XXX U_XXX ();  // cannot be detected
+endmodule
+
+class foo;
+  // from a design pattern in UVM
+  `xxx_begin(bar) // must be ignored
+  `xxx_end        // must be ignored
+
+  function new(string name="...");
+    super.new(name);
+  endfunction : new
+
+  // from systemverilog-directive.d
+  var `add_t(foo) = '0;
+endclass : foo

parsers/verilog.c

@@ -830,14 +830,19 @@ static int skipMacro (int c, tokenInfo *token)
 			c = processDefine (localToken, c);
 		}
 		/* return macro expansion */
-		else
+		else if (localToken->kind == K_IDENTIFIER)
 		{
 			swapToken (token, localToken);
 			c = skipWhite (c);
 			if (c == '(')
 				c = skipPastMatch ("()");
 			break;
 		}
+		else
+		{
+			VERBOSE ("Unexpected input: localToken->kind %d\n", localToken->kind);
+			break;
+		}
 	}
 	deleteToken (localToken);
 	return c;
@@ -877,7 +882,7 @@ static int readWordToken (tokenInfo *const token, int c)
 
 // read a word token starting with "c".
 // returns the next charactor of the token read.
-// for compiler directives. Since they are line-based, skipWhite() cannot be used.
+// For compiler directives which are line-based, skipWhite() cannot be used.
 static int readWordTokenNoSkip (tokenInfo *const token, int c)
 {
 	return _readWordToken (token, c, false);
@@ -894,7 +899,8 @@ static bool isIdentifier (tokenInfo* token)
 			int c = vStringChar (token->name, i);
 			if (i == 0)
 			{
-				if (c == '`' || !isWordToken (c))
+				// treat a text-macro as an identifier (#3712)
+				if (!isWordToken (c))
 					return false;
 			}
 			else
@@ -2080,14 +2086,20 @@ static void findVerilogTags (void)
 			default :
 				if (isWordToken (c))
 				{
+					// NoSkip for compiler directives
 					c = readWordTokenNoSkip (token, c);
 					if (token->kind == K_DIRECTIVE)
 					{
 						// Skip compiler directives which are line-based.
 						c = skipToNewLine (c);
 						c = skipWhite (c);
 					}
-					else if (token->kind != K_UNDEFINED)
+					else if ((token->kind == K_UNDEFINED)
+							 || (token->kind == K_IDENTIFIER && vStringChar(token->name, 0) == '`'))
+						// ignore an undefined token and text-macro identifier, i.e.`foo(bar) (#3712)
+						break;
+					else
+						// call findTag() after skipping whitespaces
 						c = findTag (token, skipWhite (c));
 				}
 				else