From c7017f7f79899a3372678bea829fb92764f370e0 Mon Sep 17 00:00:00 2001
From: Robert O'Callahan <rocallahan@google.com>
Date: Thu, 3 Jul 2025 23:47:25 +0000
Subject: [PATCH] Remove `log_str()` functions and convert their `log_signal()`
 users to return `std::string`

This is a small but easy step towards removing the `log_id_cache`.
See issue #5210.
---
 kernel/drivertools.cc | 30 +++++++++++++++---------------
 kernel/drivertools.h  | 11 ++++++-----
 kernel/functional.cc  |  4 ++--
 kernel/log.cc         | 10 ----------
 kernel/log.h          |  2 --
 5 files changed, 23 insertions(+), 34 deletions(-)

diff --git a/kernel/drivertools.cc b/kernel/drivertools.cc
index b8905d68c..6290f4470 100644
--- a/kernel/drivertools.cc
+++ b/kernel/drivertools.cc
@@ -865,41 +865,41 @@ DriveSpec DriverMap::operator()(DriveSpec spec)
 	return result;
 }
 
-const char *log_signal(DriveChunkWire const &chunk)
+std::string log_signal(DriveChunkWire const &chunk)
 {
 	const char *id = log_id(chunk.wire->name);
 	if (chunk.is_whole())
 		return id;
 	if (chunk.width == 1)
-		return log_str(stringf("%s [%d]", id, chunk.offset));
-	return log_str(stringf("%s [%d:%d]", id, chunk.offset + chunk.width - 1, chunk.offset));
+		return stringf("%s [%d]", id, chunk.offset);
+	return stringf("%s [%d:%d]", id, chunk.offset + chunk.width - 1, chunk.offset);
 }
 
 
-const char *log_signal(DriveChunkPort const &chunk)
+std::string log_signal(DriveChunkPort const &chunk)
 {
 	const char *cell_id = log_id(chunk.cell->name);
 	const char *port_id = log_id(chunk.port);
 	if (chunk.is_whole())
-		return log_str(stringf("%s <%s>", cell_id, port_id));
+		return stringf("%s <%s>", cell_id, port_id);
 	if (chunk.width == 1)
-		return log_str(stringf("%s <%s> [%d]", cell_id, port_id, chunk.offset));
-	return log_str(stringf("%s <%s> [%d:%d]", cell_id, port_id, chunk.offset + chunk.width - 1, chunk.offset));
+		return stringf("%s <%s> [%d]", cell_id, port_id, chunk.offset);
+	return stringf("%s <%s> [%d:%d]", cell_id, port_id, chunk.offset + chunk.width - 1, chunk.offset);
 }
 
-const char *log_signal(DriveChunkMarker const &chunk)
+std::string log_signal(DriveChunkMarker const &chunk)
 {
 	if (chunk.width == 1)
-		return log_str(stringf("<marker %d> [%d]", chunk.marker, chunk.offset));
-	return log_str(stringf("<marker %d> [%d:%d]", chunk.marker, chunk.offset + chunk.width - 1, chunk.offset));
+		return stringf("<marker %d> [%d]", chunk.marker, chunk.offset);
+	return stringf("<marker %d> [%d:%d]", chunk.marker, chunk.offset + chunk.width - 1, chunk.offset);
 }
 
-const char *log_signal(DriveChunk const &chunk)
+std::string log_signal(DriveChunk const &chunk)
 {
 	switch (chunk.type())
 	{
 		case DriveType::NONE:
-			return log_str(stringf("<none x%d>", chunk.size()));
+			return stringf("<none x%d>", chunk.size());
 		case DriveType::CONSTANT:
 			return log_const(chunk.constant());
 		case DriveType::WIRE:
@@ -917,14 +917,14 @@ const char *log_signal(DriveChunk const &chunk)
 				str += log_signal(single);
 			}
 			str += ">";
-			return log_str(str);
+			return str;
 		}
 		default:
 			log_abort();
 	}
 }
 
-const char *log_signal(DriveSpec const &spec)
+std::string log_signal(DriveSpec const &spec)
 {
 	auto &chunks = spec.chunks();
 	if (chunks.empty())
@@ -943,7 +943,7 @@ const char *log_signal(DriveSpec const &spec)
 	}
 	str += " }";
 
-	return log_str(str);
+	return str;
 }
 
 YOSYS_NAMESPACE_END
diff --git a/kernel/drivertools.h b/kernel/drivertools.h
index d46217da5..ba7b2aa84 100644
--- a/kernel/drivertools.h
+++ b/kernel/drivertools.h
@@ -20,6 +20,7 @@
 #ifndef DRIVERTOOLS_H
 #define DRIVERTOOLS_H
 
+#include <string>
 #include <type_traits>
 
 #include "kernel/rtlil.h"
@@ -39,11 +40,11 @@ struct DriveChunk;
 
 struct DriveSpec;
 
-const char *log_signal(DriveChunkWire const &chunk);
-const char *log_signal(DriveChunkPort const &chunk);
-const char *log_signal(DriveChunkMarker const &chunk);
-const char *log_signal(DriveChunk const &chunk);
-const char *log_signal(DriveSpec const &chunk);
+std::string log_signal(DriveChunkWire const &chunk);
+std::string log_signal(DriveChunkPort const &chunk);
+std::string log_signal(DriveChunkMarker const &chunk);
+std::string log_signal(DriveChunk const &chunk);
+std::string log_signal(DriveSpec const &chunk);
 
 enum class DriveType : unsigned char
 {
diff --git a/kernel/functional.cc b/kernel/functional.cc
index 211527926..66dc2e1eb 100644
--- a/kernel/functional.cc
+++ b/kernel/functional.cc
@@ -638,7 +638,7 @@ private:
 			}
 		}
 	}
-	void undriven(const char *name) {
+	void undriven(const std::string& name) {
 		log_error("The design contains an undriven signal %s. This is not supported by the functional backend. "
 			"Call setundef with appropriate options to avoid this error.\n", name);
 	}
@@ -646,7 +646,7 @@ private:
 	void check_undriven(DriveSpec const& spec, std::string const& name) {
 		for(auto const &chunk : spec.chunks())
 			if(chunk.is_none())
-				undriven(name.c_str());
+				undriven(name);
 	}
 public:
 	void process_queue()
diff --git a/kernel/log.cc b/kernel/log.cc
index 0dd56a04f..a03f16350 100644
--- a/kernel/log.cc
+++ b/kernel/log.cc
@@ -621,16 +621,6 @@ const char *log_id(const RTLIL::IdString &str)
 	return log_id_cache.back();
 }
 
-const char *log_str(const char *str)
-{
-	log_id_cache.push_back(strdup(str));
-	return log_id_cache.back();
-}
-
-const char *log_str(std::string const &str) {
-	return log_str(str.c_str());
-}
-
 void log_module(RTLIL::Module *module, std::string indent)
 {
 	std::stringstream buf;
diff --git a/kernel/log.h b/kernel/log.h
index 5143524bf..1f32e8185 100644
--- a/kernel/log.h
+++ b/kernel/log.h
@@ -256,8 +256,6 @@ void log_check_expected();
 const char *log_signal(const RTLIL::SigSpec &sig, bool autoint = true);
 const char *log_const(const RTLIL::Const &value, bool autoint = true);
 const char *log_id(const RTLIL::IdString &id);
-const char *log_str(const char *str);
-const char *log_str(std::string const &str);
 
 template<typename T> static inline const char *log_id(T *obj, const char *nullstr = nullptr) {
 	if (nullstr && obj == nullptr)