From 0cdd7e9e2e8bbb873fdde835681339daf6a32bcb Mon Sep 17 00:00:00 2001
From: nikitalita <69168929+nikitalita@users.noreply.github.com>
Date: Sun, 2 Mar 2025 15:55:20 -0800
Subject: [PATCH] start debug server in d_main, add `vm_debug` cvars and
 `-debug` CLI arg

---
 src/d_main.cpp | 53 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 52 insertions(+), 1 deletion(-)

diff --git a/src/d_main.cpp b/src/d_main.cpp
index 875f892bf9..1efe65b2ba 100644
--- a/src/d_main.cpp
+++ b/src/d_main.cpp
@@ -118,6 +118,7 @@
 #include "screenjob.h"
 #include "startscreen.h"
 #include "shiftstate.h"
+#include "common/scripting/dap/DebugServer.h"
 
 #ifdef __unix__
 #include "i_system.h"  // for SHARE_DIR
@@ -130,6 +131,8 @@ EXTERN_CVAR(Int, vr_mode)
 EXTERN_CVAR(Bool, cl_customizeinvulmap)
 EXTERN_CVAR(Bool, log_vgafont)
 EXTERN_CVAR(Bool, dlg_vgafont)
+EXTERN_CVAR(Bool, vm_jit)
+EXTERN_CVAR(Bool, vm_jit_aot)
 CVAR(Int, vid_renderer, 1, 0)	// for some stupid mods which threw caution out of the window...
 
 void DrawHUD();
@@ -334,6 +337,7 @@ extern bool AppActive;
 bool playedtitlemusic;
 
 FStartScreen* StartScreen;
+std::unique_ptr<DebugServer::DebugServer> debugServer;
 
 cycle_t FrameCycles;
 
@@ -2651,6 +2655,23 @@ CUSTOM_CVAR(Int, mouse_capturemode, 1, CVAR_GLOBALCONFIG | CVAR_ARCHIVE)
 	}
 }
 
+CUSTOM_CVAR(Bool, vm_debug, false, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
+{
+	if (vm_debug == false){
+		if (debugServer){
+			debugServer->Stop();
+			debugServer = nullptr;
+		}
+	} else {
+		// TODO: we wouldn't need to do this if we were able to recompile everything when it's enabled?
+		Printf("You must restart " GAMENAME " for this change to take effect.\n");
+		Printf("Note that enabling the debug server will disable JIT compilation.\n");
+	}
+	// TODO: save this to the config file?
+
+}
+
+CVAR(Int, vm_debug_port, 19021, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
 
 void Mlook_ReleaseHandler()
 {
@@ -3400,9 +3421,14 @@ static int D_InitGame(const FIWADInfo* iwad_info, std::vector<std::string>& allw
 	M_Init();
 	M_CreateGameMenus();
 
+	bool should_debug = vm_debug.get();
+	if (Args->CheckValue("-debug")) {
+		should_debug = true;
+	}
 
 	// clean up the compiler symbols which are not needed any longer.
-	RemoveUnusedSymbols();
+  if (!should_debug)
+	  RemoveUnusedSymbols();
 
 	InitActorNumsFromMapinfo();
 	InitSpawnablesFromMapinfo();
@@ -3702,6 +3728,12 @@ static int D_DoomMain_Internal (void)
 	// Now that we have the IWADINFO, initialize the autoload ini sections.
 	GameConfig->DoAutoloadSetup(iwad_man);
 
+	bool should_debug = vm_debug.get();
+	const char * debug_port_arg = Args->CheckValue("-debug");
+	if (debug_port_arg) {
+		should_debug = true;
+	}
+
 	// reinit from here
 
 	do
@@ -3755,6 +3787,25 @@ static int D_DoomMain_Internal (void)
 
 		D_DoAnonStats();
 		I_UpdateWindowTitle();
+
+		// Launch debug server if enabled
+		if (should_debug) {
+			debugServer = std::make_unique<DebugServer::DebugServer>();
+			int debug_port = vm_debug_port.get()->ToInt();
+			if (should_debug) {
+				if (debug_port_arg) {
+					debug_port = atoi(debug_port_arg);
+				}
+			}
+			if (debug_port > 65535 || debug_port < 0) {
+				I_FatalError("Invalid debug port %d (must be between 0 and 65535)", debug_port);
+			}
+			debugServer->Listen(debug_port);
+			// disable vm_jit and vm_jit_aot when debugging
+			vm_jit = false;
+			vm_jit_aot = false;
+		}
+
 		D_DoomLoop ();		// this only returns if a 'restart' CCMD is given.
 		// 
 		// Clean up after a restart