From 91dd87e60b120119ee34a9961a7b5f33f340282e Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Tue, 5 Aug 2014 12:15:53 +0200
Subject: [PATCH] Improved scope resolution of local regs in Verilog+AST
 frontend

---
 frontends/ast/ast.h        |  2 +-
 frontends/ast/simplify.cc  | 31 +++++++++++++++----
 frontends/verilog/parser.y |  3 +-
 tests/simple/scopes.v      | 63 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 90 insertions(+), 9 deletions(-)
 create mode 100644 tests/simple/scopes.v

diff --git a/frontends/ast/ast.h b/frontends/ast/ast.h
index 83798edf0..00b044bc4 100644
--- a/frontends/ast/ast.h
+++ b/frontends/ast/ast.h
@@ -200,7 +200,7 @@ namespace AST
 		// it also sets the id2ast pointers so that identifier lookups are fast in genRTLIL()
 		bool simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage, int width_hint, bool sign_hint, bool in_param);
 		void expand_genblock(std::string index_var, std::string prefix, std::map<std::string, std::string> &name_map);
-		void replace_ids(std::map<std::string, std::string> &rules);
+		void replace_ids(const std::string &prefix, const std::map<std::string, std::string> &rules);
 		void mem2reg_as_needed_pass1(std::map<AstNode*, std::set<std::string>> &mem2reg_places,
 				std::map<AstNode*, uint32_t> &mem2reg_flags, std::map<AstNode*, uint32_t> &proc_flags, uint32_t &status_flags);
 		void mem2reg_as_needed_pass2(std::set<AstNode*> &mem2reg_set, AstNode *mod, AstNode *block);
diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 20edc1739..29d00be96 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -794,6 +794,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			if (children[i]->type == AST_WIRE) {
 				children[i]->simplify(false, false, false, stage, -1, false, false);
 				current_ast_mod->children.push_back(children[i]);
+				current_scope[children[i]->str] = children[i];
 			} else
 				new_children.push_back(children[i]);
 
@@ -1492,7 +1493,7 @@ skip_dynamic_range_lvalue_expansion:;
 			if (child->type != AST_WIRE)
 			{
 				AstNode *stmt = child->clone();
-				stmt->replace_ids(replace_rules);
+				stmt->replace_ids(prefix, replace_rules);
 
 				for (auto it = current_block->children.begin(); it != current_block->children.end(); it++) {
 					if (*it != current_block_child)
@@ -1855,12 +1856,30 @@ void AstNode::expand_genblock(std::string index_var, std::string prefix, std::ma
 }
 
 // rename stuff (used when tasks of functions are instanciated)
-void AstNode::replace_ids(std::map<std::string, std::string> &rules)
+void AstNode::replace_ids(const std::string &prefix, const std::map<std::string, std::string> &rules)
 {
-	if (type == AST_IDENTIFIER && rules.count(str) > 0)
-		str = rules[str];
-	for (auto child : children)
-		child->replace_ids(rules);
+	if (type == AST_BLOCK)
+	{
+		std::map<std::string, std::string> new_rules = rules;
+		std::string new_prefix = prefix + str;
+
+		for (auto child : children)
+			if (child->type == AST_WIRE) {
+				new_rules[child->str] = new_prefix + child->str;
+				child->str = new_prefix + child->str;
+			}
+
+		for (auto child : children)
+			if (child->type != AST_WIRE)
+				child->replace_ids(new_prefix, new_rules);
+	}
+	else
+	{
+		if (type == AST_IDENTIFIER && rules.count(str) > 0)
+			str = rules.at(str);
+		for (auto child : children)
+			child->replace_ids(prefix, rules);
+	}
 }
 
 // helper function for mem2reg_as_needed_pass1
diff --git a/frontends/verilog/parser.y b/frontends/verilog/parser.y
index 1e0168a5f..26e2ddc34 100644
--- a/frontends/verilog/parser.y
+++ b/frontends/verilog/parser.y
@@ -599,12 +599,11 @@ wire_name:
 				if (node->is_input || node->is_output)
 					frontend_verilog_yyerror("Module port `%s' is not declared in module header.", $1->c_str());
 			}
-			ast_stack.back()->children.push_back(node);
 		} else {
 			if (node->is_input || node->is_output)
 				node->port_id = current_function_or_task_port_id++;
-			current_function_or_task->children.push_back(node);
 		}
+		ast_stack.back()->children.push_back(node);
 		delete $1;
 	};
 
diff --git a/tests/simple/scopes.v b/tests/simple/scopes.v
new file mode 100644
index 000000000..eecc1a0b2
--- /dev/null
+++ b/tests/simple/scopes.v
@@ -0,0 +1,63 @@
+module scopes_test_01(input [3:0] k, output reg [15:0] x, y);
+	function [15:0] func_01;
+		input [15:0] x, y;
+		begin
+			func_01 = x + y;
+			begin:blk
+				reg [15:0] x;
+				x = y;
+				func_01 = func_01 ^ x;
+			end
+			func_01 = func_01 ^ x;
+		end
+	endfunction
+
+	function [15:0] func_02;
+		input [15:0] x, y;
+		begin
+			func_02 = x - y;
+			begin:blk
+				reg [15:0] func_02;
+				func_02 = 0;
+			end
+		end
+	endfunction
+
+	task task_01;
+		input [3:0] a;
+		reg [15:0] y;
+		begin
+			y = a * 23;
+			x = x + y;
+		end
+	endtask
+
+	task task_02;
+		input [3:0] a;
+		begin:foo
+			reg [15:0] x, z;
+			x = y;
+			begin:bar
+				reg [15:0] x;
+				x = 77 + a;
+				z = -x;
+			end
+			y = x ^ z;
+		end
+	endtask
+
+	always @* begin
+		x = func_01(11, 22);
+		y = func_02(33, 44);
+		task_01(k);
+		task_02(k);
+		begin:foo
+			reg [15:0] y;
+			y = x;
+			y = y + k;
+			x = y;
+		end
+		x = func_01(y, x);
+		y = func_02(y, x);
+	end
+endmodule
-- 
2.30.2