From 73167563d5f1d05ddb690038420c4b23d1d1e1dd Mon Sep 17 00:00:00 2001
From: Andrew Andrianov <andrew@ncrmnt.org>
Date: Sun, 8 Oct 2017 14:18:32 +0300
Subject: [PATCH] ivlpp: Warn about macro redefinition

Verilog spec has a very nasty system of macros jumping from
file to file, resulting in a global macro scope. We abosolutely
MUST track macro redefinitions and warn user about them.

Signed-off-by: Andrew Andrianov <andrew@ncrmnt.org>
---
 ivlpp/lexor.lex | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/ivlpp/lexor.lex b/ivlpp/lexor.lex
index c81af7397..a0aa71b42 100644
--- a/ivlpp/lexor.lex
+++ b/ivlpp/lexor.lex
@@ -858,6 +858,19 @@ void define_macro(const char* name, const char* value, int keyword, int argc)
 {
     int idx;
     struct define_t* def;
+    struct define_t* prev;
+
+    /* Verilog spec has a very nasty system of macros jumping from
+     * file to file, resulting in a global macro scope. We abosolutely
+     * MUST track macro redefinitions and warn user about them.
+     */
+
+    prev = def_lookup(name);
+    if (prev) {
+        emit_pathline(istack);
+        fprintf(stderr, "warning: redefinition of macro %s\n",
+            name);
+    }
 
     def = malloc(sizeof(struct define_t));
     def->name = strdup(name);