From c4f435569f6c8d3649ed82d5d2e2588f94b0b6c5 Mon Sep 17 00:00:00 2001
From: Jannis Harder <me@jix.one>
Date: Wed, 3 Sep 2025 15:29:08 +0200
Subject: [PATCH] kernel: Add known_driver method to Wire/SigSpec

---
 kernel/rtlil.cc | 9 +++++++++
 kernel/rtlil.h  | 4 ++++
 2 files changed, 13 insertions(+)

diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 4e94b8cc1..5f8e6ad66 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -5534,6 +5534,15 @@ bool RTLIL::SigSpec::is_chunk() const
 	return GetSize(chunks_) == 1;
 }
 
+bool RTLIL::SigSpec::known_driver() const
+{
+	pack();
+	for (auto &chunk : chunks_)
+		if (chunk.is_wire() && !chunk.wire->known_driver())
+			return false;
+	return true;
+}
+
 bool RTLIL::SigSpec::is_fully_const() const
 {
 	cover("kernel.rtlil.sigspec.is_fully_const");
diff --git a/kernel/rtlil.h b/kernel/rtlil.h
index 4c3e2182e..15154eb64 100644
--- a/kernel/rtlil.h
+++ b/kernel/rtlil.h
@@ -1329,6 +1329,8 @@ public:
 	bool is_chunk() const;
 	inline bool is_bit() const { return width_ == 1; }
 
+	bool known_driver() const;
+
 	bool is_fully_const() const;
 	bool is_fully_zero() const;
 	bool is_fully_ones() const;
@@ -2059,6 +2061,8 @@ public:
 	int width, start_offset, port_id;
 	bool port_input, port_output, upto, is_signed;
 
+	bool known_driver() const { return driverCell_ != nullptr; }
+
 	RTLIL::Cell *driverCell() const    { log_assert(driverCell_); return driverCell_; };
 	RTLIL::IdString driverPort() const { log_assert(driverCell_); return driverPort_; };