Internals: Generate ASTGEN_SUPER_* macros instead of expanding. (#2975)

astgen now generates ASTGEN_SUPER_* macros, instead of expanding the
ASTGEN_SUPER itself. This means that V3AstNodes.h itself can be included
in V3Ast.h, which helps IDEs (namely CLion) find definitions in
V3AstNodes.h a lot better. Albeit this is a little bit more boilerplate,
writing constructors of Ast nodes should be a lot rarer than trying to
find their definitions, so hopefully this is an improvement overall.
astgen will error if the developer calls the wrong superclass
constructor.

src/V3Ast.h

@@ -2916,7 +2916,7 @@ public:
 
 //######################################################################
 
-#include "V3AstNodes__gen.h"
+#include "V3AstNodes.h"
 
 //######################################################################
 // Inline AstNVisitor METHODS

src/V3AstNodes.cpp

@@ -25,6 +25,8 @@
 #include "V3String.h"
 #include "V3EmitCBase.h"
 
+#include "V3AstNodes__gen_macros.h"  // Generated by 'astgen'
+
 #include <iomanip>
 #include <vector>
 
@@ -214,7 +216,7 @@ AstNodeBiop* AstEqWild::newTyped(FileLine* fl, AstNode* lhsp, AstNode* rhsp) {
 }
 
 AstExecGraph::AstExecGraph(FileLine* fileline)
-    : AstNode{AstType::atExecGraph, fileline} {
+    : ASTGEN_SUPER_ExecGraph(fileline) {
     m_depGraphp = new V3Graph;
 }
 AstExecGraph::~AstExecGraph() { VL_DO_DANGLING(delete m_depGraphp, m_depGraphp); }

src/astgen

@@ -621,7 +621,7 @@ def write_types(filename):
         fh.write("    }\n")
 
 
-def write_header(filename):
+def write_macros(filename):
     with open_file(filename) as fh:
         typen = "None"
         base = "None"
@@ -629,10 +629,7 @@ def write_header(filename):
         in_filename = "V3AstNodes.h"
         ifile = Args.I + "/" + in_filename
         with open(ifile) as ifh:
-
-            fh.write("#line 1 \"../" + in_filename + "\"\n")
-
-            for line in ifh:
+            for (lineno, line) in enumerate(ifh, 1):
                 # Drop expanded macro definitions - but keep empty line so compiler
                 # message locations are accurate
                 line = re.sub(r'^\s*#(define|undef)\s+ASTGEN_.*$', '', line)
@@ -644,14 +641,18 @@ def write_header(filename):
                 if match:
                     typen = match.group(1)
                     base = match.group(4)
+                    if not typen.startswith("Node"):
+                        macro = "#define ASTGEN_SUPER_{t}(...) {b}(AstType::at{t}, __VA_ARGS__)\n" \
+                                .format(b=base, t=typen)
+                        fh.write(macro)
 
-                # Substitute macros
-                line = re.sub(r'\bASTGEN_SUPER\s*\(',
-                              base + "(AstType::at" + typen + ", ", line)
-
-                # Emit the line
-                fh.write(line)
-
+                match = re.search(r"ASTGEN_SUPER_(\w+)", line)
+                if match:
+                    if typen != match.group(1):
+                        print(("V3AstNodes.h:{l} ERROR: class Ast{t} calls wrong superclass " +
+                               "constructor macro (should call ASTGEN_SUPER_{t})")
+                              .format(l=lineno, t=typen))
+                        sys.exit(1)
 
 ######################################################################
 # main
@@ -708,7 +709,7 @@ if Args.classes:
     write_visitor("V3Ast__gen_visitor.h")
     write_impl("V3Ast__gen_impl.h")
     write_types("V3Ast__gen_types.h")
-    write_header("V3AstNodes__gen.h")
+    write_macros("V3AstNodes__gen_macros.h")
 
 for cpt in Args.infiles:
     if not re.search(r'.cpp$', cpt):