From 4ed85e9b9e183fc5c817129c1fbef67d3a3abaf5 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Tue, 23 Feb 2021 19:45:29 +0100
Subject: [PATCH] LibELF: Don't build barely-used section lookup table in
 ELF::Image

The name-to-section lookup table was only used in a handful of places,
and none of them were calling it nearly enough to justify building
a cache for it in the first place. So let's get rid of it and reduce
startup time by a little bit. :^)
---
 Userland/Libraries/LibELF/Image.cpp | 13 +++++--------
 Userland/Libraries/LibELF/Image.h   |  5 +----
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/Userland/Libraries/LibELF/Image.cpp b/Userland/Libraries/LibELF/Image.cpp
index ab085de330..07233f5e0d 100644
--- a/Userland/Libraries/LibELF/Image.cpp
+++ b/Userland/Libraries/LibELF/Image.cpp
@@ -186,12 +186,6 @@ bool Image::parse()
         }
     }
 
-    // Then create a name-to-index map.
-    for (unsigned i = 0; i < section_count(); ++i) {
-        auto section = this->section(i);
-        m_sections.set(section.name(), move(i));
-    }
-
     return m_valid;
 }
 
@@ -298,8 +292,11 @@ Image::RelocationSection Image::Section::relocations() const
 Image::Section Image::lookup_section(const String& name) const
 {
     ASSERT(m_valid);
-    if (auto it = m_sections.find(name); it != m_sections.end())
-        return section((*it).value);
+    for (unsigned i = 0; i < section_count(); ++i) {
+        auto section = this->section(i);
+        if (section.name() == name)
+            return section;
+    }
     return section(0);
 }
 
diff --git a/Userland/Libraries/LibELF/Image.h b/Userland/Libraries/LibELF/Image.h
index d477e09978..361be1a5c6 100644
--- a/Userland/Libraries/LibELF/Image.h
+++ b/Userland/Libraries/LibELF/Image.h
@@ -26,10 +26,8 @@
 
 #pragma once
 
-#include <AK/ByteBuffer.h>
-#include <AK/HashMap.h>
-#include <AK/OwnPtr.h>
 #include <AK/String.h>
+#include <AK/Vector.h>
 #include <Kernel/VirtualAddress.h>
 #include <LibELF/exec_elf.h>
 
@@ -230,7 +228,6 @@ private:
     const u8* m_buffer { nullptr };
     size_t m_size { 0 };
     bool m_verbose_logging { true };
-    HashMap<String, unsigned> m_sections;
     bool m_valid { false };
     unsigned m_symbol_table_section_index { 0 };
     unsigned m_string_table_section_index { 0 };