From 2c8b4d7ad13e4817a36b3c20f20a47b658dd5b9e Mon Sep 17 00:00:00 2001
From: Drew Lewis <cannada@google.com>
Date: Tue, 22 Jul 2025 19:49:10 +0000
Subject: [PATCH] Use unordered_map instead of dict for IdString char* to index
 storage.

dict is pretty slow when you don't ever need to iterate the container in
order.  And the hashfunction for char* in dict hashes for every single
byte in the string, likely doing significantly more work than std::hash.
---
 kernel/rtlil.cc | 2 +-
 kernel/rtlil.h  | 5 ++++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 8a0080dbf..d24ab4d1e 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -35,7 +35,7 @@ YOSYS_NAMESPACE_BEGIN
 bool RTLIL::IdString::destruct_guard_ok = false;
 RTLIL::IdString::destruct_guard_t RTLIL::IdString::destruct_guard;
 std::vector<char*> RTLIL::IdString::global_id_storage_;
-dict<char*, int> RTLIL::IdString::global_id_index_;
+std::unordered_map<std::string_view, int> RTLIL::IdString::global_id_index_;
 #ifndef YOSYS_NO_IDS_REFCNT
 std::vector<int> RTLIL::IdString::global_refcount_storage_;
 std::vector<int> RTLIL::IdString::global_free_idx_list_;
diff --git a/kernel/rtlil.h b/kernel/rtlil.h
index 504fa0062..745b8fcaf 100644
--- a/kernel/rtlil.h
+++ b/kernel/rtlil.h
@@ -23,6 +23,9 @@
 #include "kernel/yosys_common.h"
 #include "kernel/yosys.h"
 
+#include <string_view>
+#include <unordered_map>
+
 YOSYS_NAMESPACE_BEGIN
 
 namespace RTLIL
@@ -122,7 +125,7 @@ struct RTLIL::IdString
 	} destruct_guard;
 
 	static std::vector<char*> global_id_storage_;
-	static dict<char*, int> global_id_index_;
+	static std::unordered_map<std::string_view, int> global_id_index_;
 #ifndef YOSYS_NO_IDS_REFCNT
 	static std::vector<int> global_refcount_storage_;
 	static std::vector<int> global_free_idx_list_;