AK: Move memory stuff (fast memcpy, etc) to a separate header

Move the "fast memcpy" stuff out of StdLibExtras.h and into Memory.h.
This will break a ton of things that were relying on StdLibExtras.h
to include a bunch of other headers. Fix will follow immediately after.

This makes it possible to include StdLibExtras.h from Types.h, which is
the main point of this exercise.

AK/JsonParser.cpp

@@ -27,6 +27,7 @@
 #include <AK/JsonArray.h>
 #include <AK/JsonObject.h>
 #include <AK/JsonParser.h>
+#include <AK/Memory.h>
 
 namespace AK {
 

AK/Memory.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <AK/Types.h>
+
+#if defined(KERNEL) || defined(BOOTSTRAPPER)
+#    include <LibBareMetal/StdLib.h>
+#else
+#    include <stdlib.h>
+#    include <string.h>
+#endif
+
+#if defined(__serenity__) && !defined(KERNEL) && !defined(BOOTSTRAPPER)
+extern "C" void* mmx_memcpy(void* to, const void* from, size_t);
+#endif
+
+[[gnu::always_inline]] inline void fast_u32_copy(u32* dest, const u32* src, size_t count)
+{
+#if defined(__serenity__) && !defined(KERNEL) && !defined(BOOTSTRAPPER)
+    if (count >= 256) {
+        mmx_memcpy(dest, src, count * sizeof(count));
+        return;
+    }
+#endif
+    asm volatile(
+        "rep movsl\n"
+        : "=S"(src), "=D"(dest), "=c"(count)
+        : "S"(src), "D"(dest), "c"(count)
+        : "memory");
+}
+
+[[gnu::always_inline]] inline void fast_u32_fill(u32* dest, u32 value, size_t count)
+{
+    asm volatile(
+        "rep stosl\n"
+        : "=D"(dest), "=c"(count)
+        : "D"(dest), "c"(count), "a"(value)
+        : "memory");
+}

AK/Optional.h

@@ -29,6 +29,7 @@
 #include <AK/Assertions.h>
 #include <AK/Platform.h>
 #include <AK/StdLibExtras.h>
+#include <AK/Types.h>
 
 namespace AK {
 
@@ -157,7 +158,7 @@ private:
         ASSERT(m_has_value);
         return *reinterpret_cast<const T*>(&m_storage);
     }
-    unsigned char m_storage[sizeof(T)] { 0 };
+    u8 m_storage[sizeof(T)] { 0 };
     bool m_has_value { false };
 };
 

AK/SinglyLinkedList.h

@@ -28,6 +28,7 @@
 
 #include <AK/Assertions.h>
 #include <AK/StdLibExtras.h>
+#include <AK/Types.h>
 
 namespace AK {
 

AK/StdLibExtras.h

@@ -26,46 +26,9 @@
 
 #pragma once
 
-#if defined(KERNEL) || defined(BOOTSTRAPPER)
-#    include <LibBareMetal/StdLib.h>
-#else
-#    include <stdlib.h>
-#    include <string.h>
-#endif
-
 #define UNUSED_PARAM(x) (void)x
 
-#include <AK/Types.h>
+inline constexpr unsigned round_up_to_power_of_two(unsigned value, unsigned power_of_two)
-
-#if defined(__serenity__) && !defined(KERNEL) && !defined(BOOTSTRAPPER)
-extern "C" void* mmx_memcpy(void* to, const void* from, size_t);
-#endif
-
-[[gnu::always_inline]] inline void fast_u32_copy(u32* dest, const u32* src, size_t count)
-{
-#if defined(__serenity__) && !defined(KERNEL) && !defined(BOOTSTRAPPER)
-    if (count >= 256) {
-        mmx_memcpy(dest, src, count * sizeof(count));
-        return;
-    }
-#endif
-    asm volatile(
-        "rep movsl\n"
-        : "=S"(src), "=D"(dest), "=c"(count)
-        : "S"(src), "D"(dest), "c"(count)
-        : "memory");
-}
-
-[[gnu::always_inline]] inline void fast_u32_fill(u32* dest, u32 value, size_t count)
-{
-    asm volatile(
-        "rep stosl\n"
-        : "=D"(dest), "=c"(count)
-        : "D"(dest), "c"(count), "a"(value)
-        : "memory");
-}
-
-inline constexpr u32 round_up_to_power_of_two(u32 value, u32 power_of_two)
 {
     return ((value - 1) & ~(power_of_two - 1)) + power_of_two;
 }

AK/String.cpp

@@ -24,6 +24,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <AK/Memory.h>
 #include <AK/StdLibExtras.h>
 #include <AK/String.h>
 #include <AK/StringBuilder.h>

AK/String.h

@@ -252,7 +252,7 @@ inline bool StringView::operator==(const String& string) const
         return false;
     if (m_characters == string.characters())
         return true;
-    return !memcmp(m_characters, string.characters(), m_length);
+    return !__builtin_memcmp(m_characters, string.characters(), m_length);
 }
 
 template<>

AK/StringBuilder.cpp

@@ -24,10 +24,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <AK/Memory.h>
 #include <AK/PrintfImplementation.h>
 #include <AK/StdLibExtras.h>
-#include <AK/StringBuilder.h>
 #include <AK/String.h>
+#include <AK/StringBuilder.h>
 
 namespace AK {
 

AK/StringImpl.cpp

@@ -24,10 +24,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include "StringImpl.h"
+#include <AK/HashTable.h>
-#include "HashTable.h"
+#include <AK/Memory.h>
-#include "StdLibExtras.h"
+#include <AK/StdLibExtras.h>
-#include "kmalloc.h"
+#include <AK/StringImpl.h>
+#include <AK/kmalloc.h>
 
 //#define DEBUG_STRINGIMPL
 

AK/StringView.cpp

@@ -25,6 +25,7 @@
  */
 
 #include <AK/ByteBuffer.h>
+#include <AK/Memory.h>
 #include <AK/String.h>
 #include <AK/StringView.h>
 #include <AK/Vector.h>

AK/StringView.h

@@ -47,7 +47,7 @@ public:
     }
     [[gnu::always_inline]] inline StringView(const char* cstring)
         : m_characters(cstring)
-        , m_length(cstring ? strlen(cstring) : 0)
+        , m_length(cstring ? __builtin_strlen(cstring) : 0)
     {
     }
 
@@ -105,10 +105,10 @@ public:
             return !cstring;
         if (!cstring)
             return false;
-        size_t other_length = strlen(cstring);
+        size_t other_length = __builtin_strlen(cstring);
         if (m_length != other_length)
             return false;
-        return !memcmp(m_characters, cstring, m_length);
+        return !__builtin_memcmp(m_characters, cstring, m_length);
     }
     bool operator!=(const char* cstring) const
     {
@@ -125,7 +125,7 @@ public:
             return false;
         if (length() != other.length())
             return false;
-        return !memcmp(m_characters, other.m_characters, m_length);
+        return !__builtin_memcmp(m_characters, other.m_characters, m_length);
     }
 
     bool operator!=(const StringView& other) const