From 6b5042501346197c192371105e5f111af3fb8fd0 Mon Sep 17 00:00:00 2001
From: Ali Mohammad Pur <ali.mpfard@gmail.com>
Date: Mon, 24 Oct 2022 04:01:40 +0330
Subject: [PATCH] wasm: Map the entire input wasm file instead of using
 Core::File

This is a 30x (!) speedup in parsing time as we don't lose time to
Core::File's silly memmove()-into-provided-buffer stuff anymore.
---
 Userland/Utilities/wasm.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Userland/Utilities/wasm.cpp b/Userland/Utilities/wasm.cpp
index d690cb6e6ff..2e521464a8a 100644
--- a/Userland/Utilities/wasm.cpp
+++ b/Userland/Utilities/wasm.cpp
@@ -8,6 +8,7 @@
 #include <LibCore/ArgsParser.h>
 #include <LibCore/File.h>
 #include <LibCore/FileStream.h>
+#include <LibCore/MappedFile.h>
 #include <LibLine/Editor.h>
 #include <LibMain/Main.h>
 #include <LibWasm/AbstractMachine/AbstractMachine.h>
@@ -245,13 +246,13 @@ static bool pre_interpret_hook(Wasm::Configuration& config, Wasm::InstructionPoi
 
 static Optional<Wasm::Module> parse(StringView filename)
 {
-    auto result = Core::File::open(filename, Core::OpenMode::ReadOnly);
+    auto result = Core::MappedFile::map(filename);
     if (result.is_error()) {
         warnln("Failed to open {}: {}", filename, result.error());
         return {};
     }
 
-    auto stream = Core::InputFileStream(result.release_value());
+    InputMemoryStream stream { ReadonlyBytes { result.value()->data(), result.value()->size() } };
     auto parse_result = Wasm::Module::parse(stream);
     if (parse_result.is_error()) {
         warnln("Something went wrong, either the file is invalid, or there's a bug with LibWasm!");