From dac5adde12c585f5e0552f776ae0a5ab05e995c9 Mon Sep 17 00:00:00 2001
From: Eddie Hung <eddie@fpgeh.com>
Date: Thu, 16 Apr 2020 12:46:07 -0700
Subject: [PATCH 1/2] design: -import to not count black/white-boxes as
 candidates for top

---
 passes/cmds/design.cc | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/passes/cmds/design.cc b/passes/cmds/design.cc
index cfe97067d..421defe0c 100644
--- a/passes/cmds/design.cc
+++ b/passes/cmds/design.cc
@@ -228,14 +228,20 @@ struct DesignPass : public Pass {
 			}
 
 			if (import_mode) {
+				std::vector<RTLIL::Module*> candidates;
 				for (auto module : copy_src_modules)
 				{
 					if (module->get_bool_attribute(ID::top)) {
-						copy_src_modules.clear();
-						copy_src_modules.push_back(module);
+						candidates.clear();
+						candidates.push_back(module);
 						break;
 					}
+					if (!module->get_blackbox_attribute())
+						candidates.push_back(module);
 				}
+
+				if (GetSize(candidates) == 1)
+					copy_src_modules = std::move(candidates);
 			}
 		}
 

From 9eace8f36032665394e582a60fc58be0a7c9303b Mon Sep 17 00:00:00 2001
From: Eddie Hung <eddie@fpgeh.com>
Date: Thu, 16 Apr 2020 12:48:40 -0700
Subject: [PATCH 2/2] design: add test

---
 tests/various/design.ys  | 18 +++++++++++++-----
 tests/various/design1.ys |  9 +++++++++
 2 files changed, 22 insertions(+), 5 deletions(-)
 create mode 100644 tests/various/design1.ys

diff --git a/tests/various/design.ys b/tests/various/design.ys
index f13ad8171..a64430dc7 100644
--- a/tests/various/design.ys
+++ b/tests/various/design.ys
@@ -1,9 +1,17 @@
 read_verilog <<EOT
+(* blackbox *)
+module bb(input i, output o);
+endmodule
+
+(* whitebox *)
+module wb(input i, output o);
+assign o = ~i;
+endmodule
+
 module top(input i, output o);
-assign o = i;
+assign o = ~i;
 endmodule
 EOT
-design -stash foo
-design -delete foo
-logger -expect error "No saved design 'foo' found!" 1
-design -delete foo
+
+design -stash gate
+design -import gate -as gate
diff --git a/tests/various/design1.ys b/tests/various/design1.ys
new file mode 100644
index 000000000..f13ad8171
--- /dev/null
+++ b/tests/various/design1.ys
@@ -0,0 +1,9 @@
+read_verilog <<EOT
+module top(input i, output o);
+assign o = i;
+endmodule
+EOT
+design -stash foo
+design -delete foo
+logger -expect error "No saved design 'foo' found!" 1
+design -delete foo