From 00f97073992b393c7eac4f1a6ec4311cb8a21cb1 Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sun, 19 Dec 2021 10:40:33 -0800
Subject: [PATCH] jit: Use a hash for invalidate/clear all.

This should make sceKernelICacheClearAll() more useful.
---
 Core/MIPS/JitCommon/JitBlockCache.cpp | 25 +++++++++++++++++++++++--
 Core/MIPS/JitCommon/JitBlockCache.h   |  3 +++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/Core/MIPS/JitCommon/JitBlockCache.cpp b/Core/MIPS/JitCommon/JitBlockCache.cpp
index 3f5e797312..7a0e3179f2 100644
--- a/Core/MIPS/JitCommon/JitBlockCache.cpp
+++ b/Core/MIPS/JitCommon/JitBlockCache.cpp
@@ -19,7 +19,9 @@
 #include <cstddef>
 #include <algorithm>
 
+#include "ext/xxhash.h"
 #include "Common.h"
+#include "Common/Profiler/Profiler.h"
 
 #ifdef _WIN32
 #include "Common/CommonWindows.h"
@@ -59,6 +61,15 @@ op_agent_t agent;
 
 const u32 INVALID_EXIT = 0xFFFFFFFF;
 
+static uint64_t HashJitBlock(const JitBlock &b) {
+	PROFILE_THIS_SCOPE("jithash");
+	if (JIT_USE_COMPILEDHASH) {
+		// Includes the emuhack (or emuhacks) in memory.
+		return XXH3_64bits(Memory::GetPointer(b.originalAddress), b.originalSize * 4);
+	}
+	return 0;
+}
+
 JitBlockCache::JitBlockCache(MIPSState *mipsState, CodeBlockCommon *codeBlock) :
 	codeBlock_(codeBlock), blocks_(nullptr), num_blocks_(0) {
 }
@@ -234,6 +245,9 @@ void JitBlockCache::FinalizeBlock(int block_num, bool block_link) {
 	MIPSOpcode opcode = GetEmuHackOpForBlock(block_num);
 	Memory::Write_Opcode_JIT(b.originalAddress, opcode);
 
+	// Note that this hashes the emuhack too, which is intentional.
+	b.compiledHash = HashJitBlock(b);
+
 	AddBlockMap(block_num);
 
 	if (block_link) {
@@ -592,8 +606,15 @@ void JitBlockCache::InvalidateChangedBlocks() {
 		if (b.invalid || b.IsPureProxy())
 			continue;
 
-		const u32 emuhack = GetEmuHackOpForBlock(block_num).encoding;
-		if (Memory::ReadUnchecked_U32(b.originalAddress) != emuhack) {
+		bool changed = false;
+		if (JIT_USE_COMPILEDHASH) {
+			changed = b.compiledHash != HashJitBlock(b);
+		} else {
+			const u32 emuhack = GetEmuHackOpForBlock(block_num).encoding;
+			changed = Memory::ReadUnchecked_U32(b.originalAddress) != emuhack;
+		}
+
+		if (changed) {
 			DEBUG_LOG(JIT, "Invalidating changed block at %08x", b.originalAddress);
 			DestroyBlock(block_num, DestroyType::INVALIDATE);
 		}
diff --git a/Core/MIPS/JitCommon/JitBlockCache.h b/Core/MIPS/JitCommon/JitBlockCache.h
index fe6217da1f..28a432fafe 100644
--- a/Core/MIPS/JitCommon/JitBlockCache.h
+++ b/Core/MIPS/JitCommon/JitBlockCache.h
@@ -17,6 +17,7 @@
 
 #pragma once
 
+#include <cstdint>
 #include <map>
 #include <unordered_map>
 #include <vector>
@@ -33,6 +34,7 @@ const int MAX_JIT_BLOCK_EXITS = 2;
 #else
 const int MAX_JIT_BLOCK_EXITS = 8;
 #endif
+constexpr bool JIT_USE_COMPILEDHASH = true;
 
 struct BlockCacheStats {
 	int numBlocks;
@@ -68,6 +70,7 @@ struct JitBlock {
 
 	u32 originalAddress;
 	MIPSOpcode originalFirstOpcode; //to be able to restore
+	uint64_t compiledHash;
 	u16 codeSize;
 	u16 originalSize;
 	u16 blockNum;