LibELF: Move ELF hash functions to their own file (and make constexpr)

Userland/Libraries/LibELF/DynamicObject.cpp

@@ -30,6 +30,7 @@
 #include <AK/StringBuilder.h>
 #include <LibELF/DynamicLoader.h>
 #include <LibELF/DynamicObject.h>
+#include <LibELF/Hashes.h>
 #include <LibELF/exec_elf.h>
 #include <string.h>
 
@@ -248,36 +249,6 @@ DynamicObject::RelocationSection DynamicObject::plt_relocation_section() const
     return RelocationSection(Section(*this, m_plt_relocation_offset_location, m_size_of_plt_relocation_entry_list, m_size_of_relocation_entry, "DT_JMPREL"));
 }
 
-u32 DynamicObject::HashSection::calculate_elf_hash(const StringView& name)
-{
-    // SYSV ELF hash algorithm
-    // Note that the GNU HASH algorithm has less collisions
-
-    uint32_t hash = 0;
-
-    for (auto ch : name) {
-        hash = hash << 4;
-        hash += ch;
-
-        const uint32_t top_nibble_of_hash = hash & 0xF0000000U;
-        hash ^= top_nibble_of_hash >> 24;
-        hash &= ~top_nibble_of_hash;
-    }
-
-    return hash;
-}
-
-u32 DynamicObject::HashSection::calculate_gnu_hash(const StringView& name)
-{
-    // GNU ELF hash algorithm
-    u32 hash = 5381;
-
-    for (auto ch : name)
-        hash = hash * 33 + ch;
-
-    return hash;
-}
-
 auto DynamicObject::HashSection::lookup_symbol(const StringView& name) const -> Optional<Symbol>
 {
     return (this->*(m_lookup_function))(name);
@@ -285,7 +256,7 @@ auto DynamicObject::HashSection::lookup_symbol(const StringView& name) const ->
 
 auto DynamicObject::HashSection::lookup_elf_symbol(const StringView& name) const -> Optional<Symbol>
 {
-    u32 hash_value = calculate_elf_hash(name);
+    u32 hash_value = compute_sysv_hash(name);
     u32* hash_table_begin = (u32*)address().as_ptr();
     size_t num_buckets = hash_table_begin[0];
 
@@ -328,7 +299,7 @@ auto DynamicObject::HashSection::lookup_gnu_symbol(const StringView& name) const
     const u32* const buckets = &bloom_words[num_maskwords];
     const u32* const chains = &buckets[num_buckets];
 
-    BloomWord hash1 = calculate_gnu_hash(name);
+    BloomWord hash1 = compute_gnu_hash(name);
     BloomWord hash2 = hash1 >> shift2;
     const BloomWord bitmask = (1 << (hash1 % bloom_word_size)) | (1 << (hash2 % bloom_word_size));
 

Userland/Libraries/LibELF/DynamicObject.h

@@ -200,9 +200,6 @@ public:
         Optional<Symbol> lookup_symbol(const StringView& name) const;
 
     private:
-        static u32 calculate_elf_hash(const StringView& name);
-        static u32 calculate_gnu_hash(const StringView& name);
-
         Optional<Symbol> lookup_elf_symbol(const StringView& name) const;
         Optional<Symbol> lookup_gnu_symbol(const StringView& name) const;
 

Userland/Libraries/LibELF/Hashes.h

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2019-2020, Andrew Kaster <andrewdkaster@gmail.com>
+ * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/StringView.h>
+
+namespace ELF {
+
+constexpr u32 compute_sysv_hash(const StringView& name)
+{
+    // SYSV ELF hash algorithm
+    // Note that the GNU HASH algorithm has less collisions
+
+    u32 hash = 0;
+
+    for (auto ch : name) {
+        hash = hash << 4;
+        hash += ch;
+
+        const u32 top_nibble_of_hash = hash & 0xf0000000u;
+        hash ^= top_nibble_of_hash >> 24;
+        hash &= ~top_nibble_of_hash;
+    }
+
+    return hash;
+}
+
+constexpr u32 compute_gnu_hash(const StringView& name)
+{
+    // GNU ELF hash algorithm
+    u32 hash = 5381;
+
+    for (auto ch : name)
+        hash = hash * 33 + ch;
+
+    return hash;
+}
+
+}