From b776283d79555ca7fdc3fa33b507a051ff2a085e Mon Sep 17 00:00:00 2001
From: Rahul Bhagwat <rahulmbme@gmail.com>
Date: Sun, 3 Aug 2025 23:31:54 -0400
Subject: [PATCH] implement package import

---
 frontends/ast/ast.cc               |  1 +
 frontends/ast/ast.h                |  1 +
 frontends/ast/genrtlil.cc          |  1 +
 frontends/ast/simplify.cc          | 36 ++++++++++++++++++++++++++++++
 frontends/verilog/verilog_lexer.l  |  1 +
 frontends/verilog/verilog_parser.y | 11 +++++++++
 6 files changed, 51 insertions(+)

diff --git a/frontends/ast/ast.cc b/frontends/ast/ast.cc
index 431f7b4f8..04f749845 100644
--- a/frontends/ast/ast.cc
+++ b/frontends/ast/ast.cc
@@ -174,6 +174,7 @@ std::string AST::type2str(AstNodeType type)
 	X(AST_MODPORT)
 	X(AST_MODPORTMEMBER)
 	X(AST_PACKAGE)
+	X(AST_IMPORT)
 	X(AST_WIRETYPE)
 	X(AST_TYPEDEF)
 	X(AST_STRUCT)
diff --git a/frontends/ast/ast.h b/frontends/ast/ast.h
index 2c2d408ce..776b5c833 100644
--- a/frontends/ast/ast.h
+++ b/frontends/ast/ast.h
@@ -153,6 +153,7 @@ namespace AST
 		AST_MODPORT,
 		AST_MODPORTMEMBER,
 		AST_PACKAGE,
+		AST_IMPORT,
 
 		AST_WIRETYPE,
 		AST_TYPEDEF,
diff --git a/frontends/ast/genrtlil.cc b/frontends/ast/genrtlil.cc
index 26ed0e3e4..79e543376 100644
--- a/frontends/ast/genrtlil.cc
+++ b/frontends/ast/genrtlil.cc
@@ -1361,6 +1361,7 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	case AST_GENIF:
 	case AST_GENCASE:
 	case AST_PACKAGE:
+	case AST_IMPORT:
 	case AST_ENUM:
 	case AST_MODPORT:
 	case AST_MODPORTMEMBER:
diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 4d8c57ced..b524fadfd 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -1103,6 +1103,42 @@ bool AstNode::simplify(bool const_fold, int stage, int width_hint, bool sign_hin
 		int counter = 0;
 		label_genblks(existing, counter);
 		std::map<std::string, AstNode*> this_wire_scope;
+		
+		// Process package imports after clearing the scope but before processing module declarations
+		for (auto &child : children) {
+			if (child->type == AST_IMPORT) {
+				// Find the package in the design
+				AstNode *package_node = nullptr;
+				for (auto &design_child : current_ast->children) {
+					if (design_child->type == AST_PACKAGE && design_child->str == child->str) {
+						package_node = design_child;
+						break;
+					}
+				}
+				
+				if (package_node) {
+					// Import all names from the package into current scope
+					for (auto &pkg_child : package_node->children) {
+						if (pkg_child->type == AST_PARAMETER || pkg_child->type == AST_LOCALPARAM || 
+							pkg_child->type == AST_TYPEDEF || pkg_child->type == AST_FUNCTION || 
+							pkg_child->type == AST_TASK || pkg_child->type == AST_ENUM) {
+							current_scope[pkg_child->str] = pkg_child;
+						}
+						if (pkg_child->type == AST_ENUM) {
+							for (auto enode : pkg_child->children) {
+								log_assert(enode->type==AST_ENUM_ITEM);
+								if (current_scope.count(enode->str) == 0)
+									current_scope[enode->str] = enode;
+								else
+									input_error("enum item %s already exists in current scope\n", enode->str.c_str());
+							}
+						}
+					}
+				} else {
+					input_error("Package `%s' not found for import\n", child->str.c_str());
+				}
+			}
+		}
 		for (size_t i = 0; i < children.size(); i++) {
 			AstNode *node = children[i];
 
diff --git a/frontends/verilog/verilog_lexer.l b/frontends/verilog/verilog_lexer.l
index e2d7a2cd9..19c0774af 100644
--- a/frontends/verilog/verilog_lexer.l
+++ b/frontends/verilog/verilog_lexer.l
@@ -334,6 +334,7 @@ TIME_SCALE_SUFFIX [munpf]?s
 "specparam"    { return TOK_SPECPARAM; }
 "package"      { SV_KEYWORD(TOK_PACKAGE); }
 "endpackage"   { SV_KEYWORD(TOK_ENDPACKAGE); }
+"import"       { SV_KEYWORD(TOK_IMPORT); }
 "interface"    { SV_KEYWORD(TOK_INTERFACE); }
 "endinterface" { SV_KEYWORD(TOK_ENDINTERFACE); }
 "modport"      { SV_KEYWORD(TOK_MODPORT); }
diff --git a/frontends/verilog/verilog_parser.y b/frontends/verilog/verilog_parser.y
index 17edc357d..bd9f47034 100644
--- a/frontends/verilog/verilog_parser.y
+++ b/frontends/verilog/verilog_parser.y
@@ -418,6 +418,7 @@ static const AstNode *addAsgnBinopStmt(dict<IdString, AstNode*> *attr, AstNode *
 %token TOK_SUB_ASSIGN TOK_DIV_ASSIGN TOK_MOD_ASSIGN TOK_MUL_ASSIGN
 %token TOK_SHL_ASSIGN TOK_SHR_ASSIGN TOK_SSHL_ASSIGN TOK_SSHR_ASSIGN
 %token TOK_BIND TOK_TIME_SCALE
+%token TOK_IMPORT
 
 %type <ast> range range_or_multirange non_opt_range non_opt_multirange
 %type <ast> wire_type expr basic_expr concat_list rvalue lvalue lvalue_concat_list non_io_wire_type io_wire_type
@@ -484,6 +485,7 @@ design:
 	localparam_decl design |
 	typedef_decl design |
 	package design |
+	import_stmt design |
 	interface design |
 	bind_directive design |
 	%empty;
@@ -730,6 +732,15 @@ package_body:
 package_body_stmt:
 	typedef_decl | localparam_decl | param_decl | task_func_decl;
 
+import_stmt:
+	TOK_IMPORT hierarchical_id TOK_PACKAGESEP '*' ';' {
+		// Create an import node to track package imports
+		AstNode *import_node = new AstNode(AST_IMPORT);
+		import_node->str = *$2;
+		ast_stack.back()->children.push_back(import_node);
+		delete $2;
+	};
+
 interface:
 	TOK_INTERFACE {
 		enterTypeScope();