From 87333f3ae236555ac1efb38b5e99b5f067900ddd Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Fri, 14 Nov 2014 19:59:50 +0100
Subject: Added warning for use of 'z' constants in HDL

---
 frontends/verilog/const2ast.cc       | 10 +++++++++-
 frontends/verilog/verilog_frontend.h |  2 +-
 frontends/verilog/verilog_parser.y   |  8 ++++----
 3 files changed, 14 insertions(+), 6 deletions(-)

(limited to 'frontends')

diff --git a/frontends/verilog/const2ast.cc b/frontends/verilog/const2ast.cc
index a81e3010..ca995915 100644
--- a/frontends/verilog/const2ast.cc
+++ b/frontends/verilog/const2ast.cc
@@ -132,8 +132,16 @@ static void my_strtobin(std::vector<RTLIL::State> &data, const char *str, int le
 }
 
 // convert the verilog code for a constant to an AST node
-AstNode *VERILOG_FRONTEND::const2ast(std::string code, char case_type)
+AstNode *VERILOG_FRONTEND::const2ast(std::string code, char case_type, bool warn_z)
 {
+	if (warn_z) {
+		AstNode *ret = const2ast(code, case_type);
+		if (std::find(ret->bits.begin(), ret->bits.end(), RTLIL::State::Sz) != ret->bits.end())
+			log_warning("Yosys does not support tri-state logic at the moment. (%s:%d)\n",
+				current_filename.c_str(), frontend_verilog_yyget_lineno());
+		return ret;
+	}
+
 	const char *str = code.c_str();
 
 	// Strings
diff --git a/frontends/verilog/verilog_frontend.h b/frontends/verilog/verilog_frontend.h
index af6495f8..e277f3e3 100644
--- a/frontends/verilog/verilog_frontend.h
+++ b/frontends/verilog/verilog_frontend.h
@@ -43,7 +43,7 @@ namespace VERILOG_FRONTEND
 	extern struct AST::AstNode *current_ast;
 
 	// this function converts a Verilog constant to an AST_CONSTANT node
-	AST::AstNode *const2ast(std::string code, char case_type = 0);
+	AST::AstNode *const2ast(std::string code, char case_type = 0, bool warn_z = false);
 
 	// state of `default_nettype
 	extern bool default_nettype_wire;
diff --git a/frontends/verilog/verilog_parser.y b/frontends/verilog/verilog_parser.y
index e40bc188..75af4652 100644
--- a/frontends/verilog/verilog_parser.y
+++ b/frontends/verilog/verilog_parser.y
@@ -1251,7 +1251,7 @@ basic_expr:
 		if ($4->substr(0, 1) != "'")
 			frontend_verilog_yyerror("Syntax error.");
 		AstNode *bits = $2;
-		AstNode *val = const2ast(*$4, case_type_stack.size() == 0 ? 0 : case_type_stack.back());
+		AstNode *val = const2ast(*$4, case_type_stack.size() == 0 ? 0 : case_type_stack.back(), true);
 		if (val == NULL)
 			log_error("Value conversion failed: `%s'\n", $4->c_str());
 		$$ = new AstNode(AST_TO_BITS, bits, val);
@@ -1262,7 +1262,7 @@ basic_expr:
 			frontend_verilog_yyerror("Syntax error.");
 		AstNode *bits = new AstNode(AST_IDENTIFIER);
 		bits->str = *$1;
-		AstNode *val = const2ast(*$2, case_type_stack.size() == 0 ? 0 : case_type_stack.back());
+		AstNode *val = const2ast(*$2, case_type_stack.size() == 0 ? 0 : case_type_stack.back(), true);
 		if (val == NULL)
 			log_error("Value conversion failed: `%s'\n", $2->c_str());
 		$$ = new AstNode(AST_TO_BITS, bits, val);
@@ -1270,14 +1270,14 @@ basic_expr:
 		delete $2;
 	} |
 	TOK_CONST TOK_CONST {
-		$$ = const2ast(*$1 + *$2, case_type_stack.size() == 0 ? 0 : case_type_stack.back());
+		$$ = const2ast(*$1 + *$2, case_type_stack.size() == 0 ? 0 : case_type_stack.back(), true);
 		if ($$ == NULL || (*$2)[0] != '\'')
 			log_error("Value conversion failed: `%s%s'\n", $1->c_str(), $2->c_str());
 		delete $1;
 		delete $2;
 	} |
 	TOK_CONST {
-		$$ = const2ast(*$1, case_type_stack.size() == 0 ? 0 : case_type_stack.back());
+		$$ = const2ast(*$1, case_type_stack.size() == 0 ? 0 : case_type_stack.back(), true);
 		if ($$ == NULL)
 			log_error("Value conversion failed: `%s'\n", $1->c_str());
 		delete $1;
-- 
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