From 82aea65bd37af760f7626648bfe82a6533ab1e31 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Tue, 9 Mar 2021 15:17:15 +0100
Subject: [PATCH] UserspaceEmulator: Add fast-path for is<MmapRegion>()

Don't use default RTTI for these since they are performance-sensitive.
---
 Userland/DevTools/UserspaceEmulator/MmapRegion.cpp | 2 +-
 Userland/DevTools/UserspaceEmulator/MmapRegion.h   | 3 +++
 Userland/DevTools/UserspaceEmulator/Region.cpp     | 3 ++-
 Userland/DevTools/UserspaceEmulator/Region.h       | 6 +++++-
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/Userland/DevTools/UserspaceEmulator/MmapRegion.cpp b/Userland/DevTools/UserspaceEmulator/MmapRegion.cpp
index 62502d8c66..ce73cfd3a7 100644
--- a/Userland/DevTools/UserspaceEmulator/MmapRegion.cpp
+++ b/Userland/DevTools/UserspaceEmulator/MmapRegion.cpp
@@ -66,7 +66,7 @@ NonnullOwnPtr<MmapRegion> MmapRegion::create_file_backed(u32 base, u32 size, u32
 }
 
 MmapRegion::MmapRegion(u32 base, u32 size, int prot, u8* data, u8* shadow_data)
-    : Region(base, size)
+    : Region(base, size, true)
     , m_data(data)
     , m_shadow_data(shadow_data)
 {
diff --git a/Userland/DevTools/UserspaceEmulator/MmapRegion.h b/Userland/DevTools/UserspaceEmulator/MmapRegion.h
index d11e3914f9..1c1c3c77ff 100644
--- a/Userland/DevTools/UserspaceEmulator/MmapRegion.h
+++ b/Userland/DevTools/UserspaceEmulator/MmapRegion.h
@@ -82,4 +82,7 @@ private:
     String m_name;
 };
 
+template<>
+inline bool Region::fast_is<MmapRegion>() const { return m_mmap; }
+
 }
diff --git a/Userland/DevTools/UserspaceEmulator/Region.cpp b/Userland/DevTools/UserspaceEmulator/Region.cpp
index 54c145a2a7..3b3f36edc0 100644
--- a/Userland/DevTools/UserspaceEmulator/Region.cpp
+++ b/Userland/DevTools/UserspaceEmulator/Region.cpp
@@ -29,9 +29,10 @@
 
 namespace UserspaceEmulator {
 
-Region::Region(u32 base, u32 size)
+Region::Region(u32 base, u32 size, bool mmap)
     : m_emulator(Emulator::the())
     , m_range(Range { VirtualAddress { base }, size })
+    , m_mmap(mmap)
 {
 }
 
diff --git a/Userland/DevTools/UserspaceEmulator/Region.h b/Userland/DevTools/UserspaceEmulator/Region.h
index f903b2387f..6dbec19ee6 100644
--- a/Userland/DevTools/UserspaceEmulator/Region.h
+++ b/Userland/DevTools/UserspaceEmulator/Region.h
@@ -79,8 +79,11 @@ public:
     Emulator& emulator() { return m_emulator; }
     const Emulator& emulator() const { return m_emulator; }
 
+    template<typename T>
+    bool fast_is() const = delete;
+
 protected:
-    Region(u32 base, u32 size);
+    Region(u32 base, u32 size, bool mmap = false);
     void set_range(Range r) { m_range = r; };
 
 private:
@@ -88,6 +91,7 @@ private:
 
     Range m_range;
 
+    bool m_mmap { false };
     bool m_stack { false };
     bool m_text { false };
     bool m_readable { true };