From dd26bcf1af3118265c9de284b8e074a5730d5d19 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Thu, 7 Nov 2024 11:06:10 +0100
Subject: [PATCH] Cache symbols and use a clipper to speed up the symbol list.

---
 Core/Debugger/SymbolMap.h    |  2 +-
 UI/ImDebugger/ImDebugger.cpp | 18 +++++++++++++-----
 UI/ImDebugger/ImDebugger.h   |  3 +++
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/Core/Debugger/SymbolMap.h b/Core/Debugger/SymbolMap.h
index b3e1529779..d888539027 100644
--- a/Core/Debugger/SymbolMap.h
+++ b/Core/Debugger/SymbolMap.h
@@ -21,7 +21,6 @@
 #include <set>
 #include <map>
 #include <string>
-#include <functional>
 #include <mutex>
 
 #include "Common/CommonTypes.h"
@@ -163,6 +162,7 @@ private:
 	// This is indexed by the end address of the module.
 	std::map<u32, const ModuleEntry> activeModuleEnds;
 
+	// Module ID, index
 	typedef std::pair<int, u32> SymbolKey;
 
 	// These are indexed by the module id and relative address in the module.
diff --git a/UI/ImDebugger/ImDebugger.cpp b/UI/ImDebugger/ImDebugger.cpp
index 4d88aecc7d..03d42cc467 100644
--- a/UI/ImDebugger/ImDebugger.cpp
+++ b/UI/ImDebugger/ImDebugger.cpp
@@ -196,13 +196,21 @@ void ImDisasmWindow::Draw(MIPSDebugInterface *mipsDebug, bool *open, CoreState c
 		ImGui::TableSetColumnIndex(0);
 		ImVec2 sz = ImGui::GetContentRegionAvail();
 		if (ImGui::BeginListBox("##symbols", ImVec2(150.0, sz.y - ImGui::GetTextLineHeightWithSpacing() * 2))) {
-			std::vector<SymbolEntry> syms = g_symbolMap->GetAllSymbols(SymbolType::ST_FUNCTION);
-			for (auto &sym : syms) {
-				if (ImGui::Selectable(sym.name.c_str(), false)) {
-					disasmView_.setCurAddress(sym.address);
-					disasmView_.scrollAddressIntoView();
+			if (symCache_.empty()) {
+				symCache_ = g_symbolMap->GetAllSymbols(SymbolType::ST_FUNCTION);
+			}
+			ImGuiListClipper clipper;
+			clipper.Begin((int)symCache_.size(), -1);
+			while (clipper.Step()) {
+				for (int i = clipper.DisplayStart; i < clipper.DisplayEnd; i++) {
+					if (ImGui::Selectable(symCache_[i].name.c_str(), false)) {
+						disasmView_.setCurAddress(symCache_[i].address);
+						disasmView_.scrollAddressIntoView();
+					}
 				}
 			}
+
+			clipper.End();
 			ImGui::EndListBox();
 		}
 
diff --git a/UI/ImDebugger/ImDebugger.h b/UI/ImDebugger/ImDebugger.h
index b0f458a26b..574aad01ae 100644
--- a/UI/ImDebugger/ImDebugger.h
+++ b/UI/ImDebugger/ImDebugger.h
@@ -37,6 +37,9 @@ private:
 
 	u32 gotoAddr_ = 0x1000;
 
+	// Symbol cache
+	std::vector<SymbolEntry> symCache_;
+
 	ImDisasmView disasmView_;
 };