From 6e84cd7f381bc5d83b51f9a847add9cf10a8077b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Wed, 11 Jun 2025 16:07:26 +0200
Subject: [PATCH] Correct the clearing/destruction order when switching JITs.

Fixes #20502
---
 Common/Log.h         |  5 +++--
 Core/MIPS/IR/IRJit.h |  3 +++
 Core/MIPS/MIPS.cpp   | 36 ++++++++++++++++++------------------
 3 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/Common/Log.h b/Common/Log.h
index 809ac060ad..fdbc245e1d 100644
--- a/Common/Log.h
+++ b/Common/Log.h
@@ -140,8 +140,9 @@ __attribute__((format(printf, 5, 6)))
 // They can have a value between 0 and 15.
 enum class DebugCounter {
 	APP_BOOT = 0,
-	GAME_BOOT = 0,
-	GAME_SHUTDOWN = 0,
+	GAME_BOOT = 1,
+	GAME_SHUTDOWN = 2,
+	CPUCORE_SWITCHES = 3,
 };
 
 bool HitAnyAsserts();
diff --git a/Core/MIPS/IR/IRJit.h b/Core/MIPS/IR/IRJit.h
index 4b3e0efac5..cf87552717 100644
--- a/Core/MIPS/IR/IRJit.h
+++ b/Core/MIPS/IR/IRJit.h
@@ -119,6 +119,9 @@ private:
 class IRBlockCache : public JitBlockCacheDebugInterface {
 public:
 	IRBlockCache(bool compileToNative);
+	~IRBlockCache() {
+		Clear();
+	}
 
 	void Clear();
 	std::vector<int> FindInvalidatedBlockNumbers(u32 address, u32 length);
diff --git a/Core/MIPS/MIPS.cpp b/Core/MIPS/MIPS.cpp
index a4a201532f..4335c45e59 100644
--- a/Core/MIPS/MIPS.cpp
+++ b/Core/MIPS/MIPS.cpp
@@ -228,39 +228,39 @@ void MIPSState::UpdateCore(CPUCore desired) {
 		return;
 	}
 
-	PSP_CoreParameter().cpuCore = desired;
-	MIPSComp::JitInterface *oldjit = MIPSComp::jit;
-	MIPSComp::JitInterface *newjit = nullptr;
+	IncrementDebugCounter(DebugCounter::CPUCORE_SWITCHES);
 
+	// Get rid of the old JIT first, before switching.
+	{
+		std::lock_guard<std::recursive_mutex> guard(MIPSComp::jitLock);
+		if (MIPSComp::jit) {
+			delete MIPSComp::jit;
+			MIPSComp::jit = nullptr;
+		}
+	}
+
+	PSP_CoreParameter().cpuCore = desired;
+
+	MIPSComp::JitInterface *newjit = nullptr;
 	switch (PSP_CoreParameter().cpuCore) {
 	case CPUCore::JIT:
 	case CPUCore::JIT_IR:
 		INFO_LOG(Log::CPU, "Switching to JIT%s", PSP_CoreParameter().cpuCore == CPUCore::JIT_IR ? " IR" : "");
-		if (oldjit) {
-			std::lock_guard<std::recursive_mutex> guard(MIPSComp::jitLock);
-			MIPSComp::jit = nullptr;
-			delete oldjit;
-		}
 		newjit = MIPSComp::CreateNativeJit(this, PSP_CoreParameter().cpuCore == CPUCore::JIT_IR);
 		break;
 
 	case CPUCore::IR_INTERPRETER:
 		INFO_LOG(Log::CPU, "Switching to IR interpreter");
-		if (oldjit) {
-			std::lock_guard<std::recursive_mutex> guard(MIPSComp::jitLock);
-			MIPSComp::jit = nullptr;
-			delete oldjit;
-		}
 		newjit = new MIPSComp::IRJit(this, false);
 		break;
 
 	case CPUCore::INTERPRETER:
 		INFO_LOG(Log::CPU, "Switching to interpreter");
-		if (oldjit) {
-			std::lock_guard<std::recursive_mutex> guard(MIPSComp::jitLock);
-			MIPSComp::jit = nullptr;
-			delete oldjit;
-		}
+		// Leaving newjit as null.
+		break;
+
+	default:
+		WARN_LOG(Log::CPU, "Invalid value for cpuCore, falling back to interpreter");
 		break;
 	}