LibWasm: Add a module pretty printer

5 files changed, 885 insertions, 16 deletions

diff --git a/Userland/Libraries/LibWasm/CMakeLists.txt b/Userland/Libraries/LibWasm/CMakeLists.txt
index c16dedeadc..0c2ef0754f 100644
--- a/Userland/Libraries/LibWasm/CMakeLists.txt
+++ b/Userland/Libraries/LibWasm/CMakeLists.txt
@@ -1,5 +1,6 @@
 set(SOURCES
     Parser/Parser.cpp
+    Printer/Printer.cpp
 )
 
 serenity_lib(LibWasm wasm)
diff --git a/Userland/Libraries/LibWasm/Printer/Printer.cpp b/Userland/Libraries/LibWasm/Printer/Printer.cpp
new file mode 100644
index 0000000000..6c6d4c4128
--- /dev/null
+++ b/Userland/Libraries/LibWasm/Printer/Printer.cpp
@@ -0,0 +1,786 @@
+/*
+ * Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/HashMap.h>
+#include <AK/TemporaryChange.h>
+#include <LibWasm/Printer/Printer.h>
+
+namespace Wasm {
+
+struct Names {
+    static HashMap<OpCode, String> instruction_names;
+};
+
+static String instruction_name(const OpCode& opcode)
+{
+    return Names::instruction_names.get(opcode).value_or("<unknown>");
+}
+
+void Printer::print_indent()
+{
+    for (size_t i = 0; i < m_indent; ++i)
+        m_stream.write_or_error("  "sv.bytes());
+}
+
+void Printer::print(const Wasm::BlockType& type)
+{
+    print_indent();
+    print("(type block ");
+    switch (type.kind()) {
+    case Wasm::BlockType::Kind::Index:
+        print("index {})\n", type.type_index().value());
+        return;
+    case Wasm::BlockType::Kind::Type: {
+        print("type\n");
+        {
+            TemporaryChange change { m_indent, m_indent + 1 };
+            print(type.value_type());
+        }
+        print_indent();
+        print(")\n");
+        return;
+    }
+    case Wasm::BlockType::Kind ::Empty:
+        print("empty)\n");
+        return;
+    }
+    VERIFY_NOT_REACHED();
+}
+
+void Printer::print(const Wasm::CodeSection& section)
+{
+    print_indent();
+    print("(section code\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        for (auto& code : section.functions())
+            print(code);
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::CodeSection::Code& code)
+{
+    print(code.func());
+}
+
+void Printer::print(const Wasm::CustomSection& section)
+{
+    print_indent();
+    print("(section custom\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print_indent();
+        print("(name `{}')\n", section.name());
+        print_indent();
+        print("(contents {} bytes)\n", section.contents().size());
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::DataCountSection& section)
+{
+    print_indent();
+    print("(section data count\n");
+    if (section.count().has_value()) {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print_indent();
+        print("(count `{}')\n", *section.count());
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::DataSection& section)
+{
+    print_indent();
+    print("(section data\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        for (auto& entry : section.data())
+            print(entry);
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::DataSection::Data& data)
+{
+    print_indent();
+    print("(data with value\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        data.value().visit(
+            [this](const DataSection::Data::Passive& value) {
+                print_indent();
+                print("(passive init {}xu8 (", value.init.size());
+                bool first = true;
+                for (auto v : value.init) {
+                    if (first)
+                        print("{:x}", v);
+                    else
+                        print(" {:x}", v);
+                    first = false;
+                }
+                print(")\n");
+            },
+            [this](const DataSection::Data::Active& value) {
+                print_indent();
+                print("(active init {}xu8 (", value.init.size());
+                bool first = true;
+                for (auto v : value.init) {
+                    if (first)
+                        print("{:x}", v);
+                    else
+                        print(" {:x}", v);
+                    first = false;
+                }
+                print("\n");
+                {
+                    TemporaryChange change { m_indent, m_indent + 1 };
+                    print_indent();
+                    print("(offset\n");
+                    {
+                        TemporaryChange change { m_indent, m_indent + 1 };
+                        print(value.offset);
+                    }
+                    print_indent();
+                    print(")\n");
+                }
+                {
+                    TemporaryChange change { m_indent, m_indent + 1 };
+                    print_indent();
+                    print("(index {})\n", value.index.value());
+                }
+            });
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::ElementSection& section)
+{
+    print_indent();
+    print("(section element\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print(section.function());
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::ElementSection::Element& element)
+{
+    print_indent();
+    print("(element\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print_indent();
+        print("(table with index {})\n", element.table().value());
+        print_indent();
+        print("(offset\n");
+        {
+            TemporaryChange change { m_indent, m_indent + 1 };
+            print(element.offset());
+        }
+        print_indent();
+        print(")\n");
+        print_indent();
+        print("(initializers\n");
+        {
+            TemporaryChange change { m_indent, m_indent + 1 };
+            for (auto& index : element.init())
+                print("(init function {})\n", index.value());
+        }
+        print_indent();
+        print(")\n");
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::ExportSection& section)
+{
+    print_indent();
+    print("(section export\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        for (auto& entry : section.entries())
+            print(entry);
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::ExportSection::Export& entry)
+{
+    print_indent();
+    print("(export `{}' as\n", entry.name());
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print_indent();
+        entry.description().visit(
+            [this](const FunctionIndex& index) { print("(function index {})\n", index.value()); },
+            [this](const TableIndex& index) { print("(table index {})\n", index.value()); },
+            [this](const MemoryIndex& index) { print("(memory index {})\n", index.value()); },
+            [this](const GlobalIndex& index) { print("(global index {})\n", index.value()); });
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::Expression& expression)
+{
+    TemporaryChange change { m_indent, m_indent + 1 };
+    for (auto& instr : expression.instructions())
+        print(instr);
+}
+
+void Printer::print(const Wasm::Func& func)
+{
+    print_indent();
+    print("(function\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        {
+            print_indent();
+            print("(locals\n");
+            {
+                TemporaryChange change { m_indent, m_indent + 1 };
+                for (auto& locals : func.locals())
+                    print(locals);
+            }
+            print_indent();
+            print(")\n");
+        }
+        print_indent();
+        print("(body\n");
+        print(func.body());
+        print_indent();
+        print(")\n");
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::FunctionSection& section)
+{
+    print_indent();
+    print("(section function\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        for (auto& index : section.types()) {
+            print_indent();
+            print("(type index {})\n", index.value());
+        }
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::FunctionType& type)
+{
+    print_indent();
+    print("(type function\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print_indent();
+        print("(parameters\n");
+        {
+            TemporaryChange change { m_indent, m_indent + 1 };
+            for (auto& param : type.parameters())
+                print(param);
+        }
+        print_indent();
+        print("\n");
+    }
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print_indent();
+        print("(results\n");
+        {
+            TemporaryChange change { m_indent, m_indent + 1 };
+            for (auto& type : type.results())
+                print(type);
+        }
+        print_indent();
+        print(")\n");
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::GlobalSection& section)
+{
+    print_indent();
+    print("(section global\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        for (auto& entry : section.entries())
+            print(entry);
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::GlobalSection::Global& entry)
+{
+    print_indent();
+    print("(global\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print_indent();
+        print("(type\n");
+        {
+            TemporaryChange change { m_indent, m_indent + 1 };
+            print(entry.type());
+        }
+        print_indent();
+        print(")\n");
+    }
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print_indent();
+        print("(init\n");
+        {
+            TemporaryChange change { m_indent, m_indent + 1 };
+            print(entry.expression());
+        }
+        print_indent();
+        print(")\n");
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::GlobalType& type)
+{
+    print_indent();
+    print("(type global {}mutable", type.is_mutable() ? "" : "im");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print(type.type());
+    }
+    print(")\n");
+}
+
+void Printer::print(const Wasm::ImportSection& section)
+{
+    print_indent();
+    print("(section import\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        for (auto& import : section.imports())
+            print(import);
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::ImportSection::Import& import)
+{
+    print_indent();
+    print("(import `{}' from `{}' as\n", import.name(), import.module());
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        import.description().visit(
+            [this](const auto& type) { print(type); },
+            [this](const TypeIndex& index) {
+                print_indent();
+                print("(type index {})\n", index.value());
+            });
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::Instruction& instruction)
+{
+    print_indent();
+    print("({}", instruction_name(instruction.opcode()));
+    if (instruction.arguments().has<u8>())
+        print(")\n");
+    else
+        print("...)\n");
+}
+
+void Printer::print(const Wasm::Limits& limits)
+{
+    print_indent();
+    print("(limits min={}", limits.min());
+    if (limits.max().has_value())
+        print(" max={}", limits.max().value());
+    else
+        print("unbounded");
+    print(")\n");
+}
+
+void Printer::print(const Wasm::Locals& local)
+{
+    print_indent();
+    print("(local x{} of type\n", local.n());
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print(local.type());
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::MemorySection& section)
+{
+    print_indent();
+    print("(section memory\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        for (auto& memory : section.memories())
+            print(memory);
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::MemorySection::Memory& memory)
+{
+    print_indent();
+    print("(memory\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print(memory.type());
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::MemoryType& type)
+{
+    print_indent();
+    print("(type memory\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print(type.limits());
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::Module& module)
+{
+    print_indent();
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print("(module\n");
+        for (auto& section : module.sections())
+            section.visit([this](const auto& value) { print(value); });
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::Module::Function& func)
+{
+    print_indent();
+    print("(function\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        {
+            print_indent();
+            print("(locals\n");
+            {
+                TemporaryChange change { m_indent, m_indent + 1 };
+                for (auto& locals : func.locals())
+                    print(locals);
+            }
+            print_indent();
+            print(")\n");
+        }
+        print_indent();
+        print("(body\n");
+        print(func.body());
+        print_indent();
+        print(")\n");
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::StartSection& section)
+{
+    print_indent();
+    print("(section start\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print(section.function());
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::StartSection::StartFunction& function)
+{
+    print_indent();
+    print("(start function index {})\n", function.index().value());
+}
+
+void Printer::print(const Wasm::TableSection& section)
+{
+    print_indent();
+    print("(section table\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        for (auto& table : section.tables())
+            print(table);
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::TableSection::Table& table)
+{
+    print_indent();
+    print("(table\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print(table.type());
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::TableType& type)
+{
+    print_indent();
+    print("(type table min:{}", type.limits().min());
+    if (type.limits().max().has_value())
+        print(" max:{}", type.limits().max().value());
+    print("\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        print(type.element_type());
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::TypeSection& section)
+{
+    print_indent();
+    print("(section type\n");
+    {
+        TemporaryChange change { m_indent, m_indent + 1 };
+        for (auto& type : section.types())
+            print(type);
+    }
+    print_indent();
+    print(")\n");
+}
+
+void Printer::print(const Wasm::ValueType& type)
+{
+    print_indent();
+    print("(type {})\n", ValueType::kind_name(type.kind()));
+}
+}
+
+HashMap<Wasm::OpCode, String> Wasm::Names::instruction_names {
+    { Instructions::unreachable, "unreachable" },
+    { Instructions::nop, "nop" },
+    { Instructions::block, "block" },
+    { Instructions::loop, "loop" },
+    { Instructions::if_, "if" },
+    { Instructions::br, "br" },
+    { Instructions::br_if, "br.if" },
+    { Instructions::br_table, "br.table" },
+    { Instructions::return_, "return." },
+    { Instructions::call, "call" },
+    { Instructions::call_indirect, "call.indirect" },
+    { Instructions::drop, "drop" },
+    { Instructions::select, "select" },
+    { Instructions::select_typed, "select.typed" },
+    { Instructions::local_get, "local.get" },
+    { Instructions::local_set, "local.set" },
+    { Instructions::local_tee, "local.tee" },
+    { Instructions::global_get, "global.get" },
+    { Instructions::global_set, "global.set" },
+    { Instructions::table_get, "table.get" },
+    { Instructions::table_set, "table.set" },
+    { Instructions::i32_load, "i32.load" },
+    { Instructions::i64_load, "i64.load" },
+    { Instructions::f32_load, "f32.load" },
+    { Instructions::f64_load, "f64.load" },
+    { Instructions::i32_load8_s, "i32.load8.s" },
+    { Instructions::i32_load8_u, "i32.load8.u" },
+    { Instructions::i32_load16_s, "i32.load16.s" },
+    { Instructions::i32_load16_u, "i32.load16.u" },
+    { Instructions::i64_load8_s, "i64.load8.s" },
+    { Instructions::i64_load8_u, "i64.load8.u" },
+    { Instructions::i64_load16_s, "i64.load16.s" },
+    { Instructions::i64_load16_u, "i64.load16.u" },
+    { Instructions::i64_load32_s, "i64.load32.s" },
+    { Instructions::i64_load32_u, "i64.load32.u" },
+    { Instructions::i32_store, "i32.store" },
+    { Instructions::i64_store, "i64.store" },
+    { Instructions::f32_store, "f32.store" },
+    { Instructions::f64_store, "f64.store" },
+    { Instructions::i32_store8, "i32.store8" },
+    { Instructions::i32_store16, "i32.store16" },
+    { Instructions::i64_store8, "i64.store8" },
+    { Instructions::i64_store16, "i64.store16" },
+    { Instructions::i64_store32, "i64.store32" },
+    { Instructions::memory_size, "memory.size" },
+    { Instructions::memory_grow, "memory.grow" },
+    { Instructions::i32_const, "i32.const" },
+    { Instructions::i64_const, "i64.const" },
+    { Instructions::f32_const, "f32.const" },
+    { Instructions::f64_const, "f64.const" },
+    { Instructions::i32_eqz, "i32.eqz" },
+    { Instructions::i32_eq, "i32.eq" },
+    { Instructions::i32_ne, "i32.ne" },
+    { Instructions::i32_lts, "i32.lts" },
+    { Instructions::i32_ltu, "i32.ltu" },
+    { Instructions::i32_gts, "i32.gts" },
+    { Instructions::i32_gtu, "i32.gtu" },
+    { Instructions::i32_les, "i32.les" },
+    { Instructions::i32_leu, "i32.leu" },
+    { Instructions::i32_ges, "i32.ges" },
+    { Instructions::i32_geu, "i32.geu" },
+    { Instructions::i64_eqz, "i64.eqz" },
+    { Instructions::i64_eq, "i64.eq" },
+    { Instructions::i64_ne, "i64.ne" },
+    { Instructions::i64_lts, "i64.lts" },
+    { Instructions::i64_ltu, "i64.ltu" },
+    { Instructions::i64_gts, "i64.gts" },
+    { Instructions::i64_gtu, "i64.gtu" },
+    { Instructions::i64_les, "i64.les" },
+    { Instructions::i64_leu, "i64.leu" },
+    { Instructions::i64_ges, "i64.ges" },
+    { Instructions::i64_geu, "i64.geu" },
+    { Instructions::f32_eq, "f32.eq" },
+    { Instructions::f32_ne, "f32.ne" },
+    { Instructions::f32_lt, "f32.lt" },
+    { Instructions::f32_gt, "f32.gt" },
+    { Instructions::f32_le, "f32.le" },
+    { Instructions::f32_ge, "f32.ge" },
+    { Instructions::f64_eq, "f64.eq" },
+    { Instructions::f64_ne, "f64.ne" },
+    { Instructions::f64_lt, "f64.lt" },
+    { Instructions::f64_gt, "f64.gt" },
+    { Instructions::f64_le, "f64.le" },
+    { Instructions::f64_ge, "f64.ge" },
+    { Instructions::i32_clz, "i32.clz" },
+    { Instructions::i32_ctz, "i32.ctz" },
+    { Instructions::i32_popcnt, "i32.popcnt" },
+    { Instructions::i32_add, "i32.add" },
+    { Instructions::i32_sub, "i32.sub" },
+    { Instructions::i32_mul, "i32.mul" },
+    { Instructions::i32_divs, "i32.divs" },
+    { Instructions::i32_divu, "i32.divu" },
+    { Instructions::i32_rems, "i32.rems" },
+    { Instructions::i32_remu, "i32.remu" },
+    { Instructions::i32_and, "i32.and" },
+    { Instructions::i32_or, "i32.or" },
+    { Instructions::i32_xor, "i32.xor" },
+    { Instructions::i32_shl, "i32.shl" },
+    { Instructions::i32_shrs, "i32.shrs" },
+    { Instructions::i32_shru, "i32.shru" },
+    { Instructions::i32_rotl, "i32.rotl" },
+    { Instructions::i32_rotr, "i32.rotr" },
+    { Instructions::i64_clz, "i64.clz" },
+    { Instructions::i64_ctz, "i64.ctz" },
+    { Instructions::i64_popcnt, "i64.popcnt" },
+    { Instructions::i64_add, "i64.add" },
+    { Instructions::i64_sub, "i64.sub" },
+    { Instructions::i64_mul, "i64.mul" },
+    { Instructions::i64_divs, "i64.divs" },
+    { Instructions::i64_divu, "i64.divu" },
+    { Instructions::i64_rems, "i64.rems" },
+    { Instructions::i64_remu, "i64.remu" },
+    { Instructions::i64_and, "i64.and" },
+    { Instructions::i64_or, "i64.or" },
+    { Instructions::i64_xor, "i64.xor" },
+    { Instructions::i64_shl, "i64.shl" },
+    { Instructions::i64_shrs, "i64.shrs" },
+    { Instructions::i64_shru, "i64.shru" },
+    { Instructions::i64_rotl, "i64.rotl" },
+    { Instructions::i64_rotr, "i64.rotr" },
+    { Instructions::f32_abs, "f32.abs" },
+    { Instructions::f32_neg, "f32.neg" },
+    { Instructions::f32_ceil, "f32.ceil" },
+    { Instructions::f32_floor, "f32.floor" },
+    { Instructions::f32_trunc, "f32.trunc" },
+    { Instructions::f32_nearest, "f32.nearest" },
+    { Instructions::f32_sqrt, "f32.sqrt" },
+    { Instructions::f32_add, "f32.add" },
+    { Instructions::f32_sub, "f32.sub" },
+    { Instructions::f32_mul, "f32.mul" },
+    { Instructions::f32_div, "f32.div" },
+    { Instructions::f32_min, "f32.min" },
+    { Instructions::f32_max, "f32.max" },
+    { Instructions::f32_copysign, "f32.copysign" },
+    { Instructions::f64_abs, "f64.abs" },
+    { Instructions::f64_neg, "f64.neg" },
+    { Instructions::f64_ceil, "f64.ceil" },
+    { Instructions::f64_floor, "f64.floor" },
+    { Instructions::f64_trunc, "f64.trunc" },
+    { Instructions::f64_nearest, "f64.nearest" },
+    { Instructions::f64_sqrt, "f64.sqrt" },
+    { Instructions::f64_add, "f64.add" },
+    { Instructions::f64_sub, "f64.sub" },
+    { Instructions::f64_mul, "f64.mul" },
+    { Instructions::f64_div, "f64.div" },
+    { Instructions::f64_min, "f64.min" },
+    { Instructions::f64_max, "f64.max" },
+    { Instructions::f64_copysign, "f64.copysign" },
+    { Instructions::i32_wrap_i64, "i32.wrap.i64" },
+    { Instructions::i32_trunc_sf32, "i32.trunc.sf32" },
+    { Instructions::i32_trunc_uf32, "i32.trunc.uf32" },
+    { Instructions::i32_trunc_sf64, "i32.trunc.sf64" },
+    { Instructions::i32_trunc_uf64, "i32.trunc.uf64" },
+    { Instructions::i64_extend_si32, "i64.extend.si32" },
+    { Instructions::i64_extend_ui32, "i64.extend.ui32" },
+    { Instructions::i64_trunc_sf32, "i64.trunc.sf32" },
+    { Instructions::i64_trunc_uf32, "i64.trunc.uf32" },
+    { Instructions::i64_trunc_sf64, "i64.trunc.sf64" },
+    { Instructions::i64_trunc_uf64, "i64.trunc.uf64" },
+    { Instructions::f32_convert_si32, "f32.convert.si32" },
+    { Instructions::f32_convert_ui32, "f32.convert.ui32" },
+    { Instructions::f32_convert_si64, "f32.convert.si64" },
+    { Instructions::f32_convert_ui64, "f32.convert.ui64" },
+    { Instructions::f32_demote_f64, "f32.demote.f64" },
+    { Instructions::f64_convert_si32, "f64.convert.si32" },
+    { Instructions::f64_convert_ui32, "f64.convert.ui32" },
+    { Instructions::f64_convert_si64, "f64.convert.si64" },
+    { Instructions::f64_convert_ui64, "f64.convert.ui64" },
+    { Instructions::f64_promote_f32, "f64.promote.f32" },
+    { Instructions::i32_reinterpret_f32, "i32.reinterpret.f32" },
+    { Instructions::i64_reinterpret_f64, "i64.reinterpret.f64" },
+    { Instructions::f32_reinterpret_i32, "f32.reinterpret.i32" },
+    { Instructions::f64_reinterpret_i64, "f64.reinterpret.i64" },
+    { Instructions::ref_null, "ref.null" },
+    { Instructions::ref_is_null, "ref.is.null" },
+    { Instructions::ref_func, "ref.func" },
+    { Instructions::i32_trunc_sat_f32_s, "i32.trunc.sat.f32.s" },
+    { Instructions::i32_trunc_sat_f32_u, "i32.trunc.sat.f32.u" },
+    { Instructions::i32_trunc_sat_f64_s, "i32.trunc.sat.f64.s" },
+    { Instructions::i32_trunc_sat_f64_u, "i32.trunc.sat.f64.u" },
+    { Instructions::i64_trunc_sat_f32_s, "i64.trunc.sat.f32.s" },
+    { Instructions::i64_trunc_sat_f32_u, "i64.trunc.sat.f32.u" },
+    { Instructions::i64_trunc_sat_f64_s, "i64.trunc.sat.f64.s" },
+    { Instructions::i64_trunc_sat_f64_u, "i64.trunc.sat.f64.u" },
+    { Instructions::memory_init, "memory.init" },
+    { Instructions::data_drop, "data.drop" },
+    { Instructions::memory_copy, "memory.copy" },
+    { Instructions::memory_fill, "memory.fill" },
+    { Instructions::table_init, "table.init" },
+    { Instructions::elem_drop, "elem.drop" },
+    { Instructions::table_copy, "table.copy" },
+    { Instructions::table_grow, "table.grow" },
+    { Instructions::table_size, "table.size" },
+    { Instructions::table_fill, "table.fill" },
+};
diff --git a/Userland/Libraries/LibWasm/Printer/Printer.h b/Userland/Libraries/LibWasm/Printer/Printer.h
new file mode 100644
index 0000000000..f39ed19a39
--- /dev/null
+++ b/Userland/Libraries/LibWasm/Printer/Printer.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWasm/Types.h>
+
+namespace Wasm {
+
+struct Printer {
+    explicit Printer(OutputStream& stream)
+        : m_stream(stream)
+    {
+    }
+
+    void print(const Wasm::BlockType&);
+    void print(const Wasm::CodeSection&);
+    void print(const Wasm::CodeSection::Code&);
+    void print(const Wasm::ConstrainedStream&);
+    void print(const Wasm::CustomSection&);
+    void print(const Wasm::DataCountSection&);
+    void print(const Wasm::DataSection&);
+    void print(const Wasm::DataSection::Data&);
+    void print(const Wasm::ElementSection&);
+    void print(const Wasm::ElementSection::Element&);
+    void print(const Wasm::ExportSection&);
+    void print(const Wasm::ExportSection::Export&);
+    void print(const Wasm::Expression&);
+    void print(const Wasm::Func&);
+    void print(const Wasm::FunctionSection&);
+    void print(const Wasm::FunctionType&);
+    void print(const Wasm::GlobalSection&);
+    void print(const Wasm::GlobalSection::Global&);
+    void print(const Wasm::GlobalType&);
+    void print(const Wasm::ImportSection&);
+    void print(const Wasm::ImportSection::Import&);
+    void print(const Wasm::Instruction&);
+    void print(const Wasm::Limits&);
+    void print(const Wasm::Locals&);
+    void print(const Wasm::MemorySection&);
+    void print(const Wasm::MemorySection::Memory&);
+    void print(const Wasm::MemoryType&);
+    void print(const Wasm::Module&);
+    void print(const Wasm::Module::Function&);
+    void print(const Wasm::ReconsumableStream&);
+    void print(const Wasm::ResultType&);
+    void print(const Wasm::StartSection&);
+    void print(const Wasm::StartSection::StartFunction&);
+    void print(const Wasm::TableSection&);
+    void print(const Wasm::TableSection::Table&);
+    void print(const Wasm::TableType&);
+    void print(const Wasm::TypeSection&);
+    void print(const Wasm::ValueType&);
+
+private:
+    void print_indent();
+    template<typename... Args>
+    void print(CheckedFormatString<Args...> fmt, Args&&... args)
+    {
+        StringBuilder builder;
+        builder.appendff(fmt.view(), forward<Args>(args)...);
+        m_stream.write_or_error(builder.string_view().bytes());
+    }
+
+    OutputStream& m_stream;
+    size_t m_indent { 0 };
+};
+
+}
diff --git a/Userland/Libraries/LibWasm/Types.h b/Userland/Libraries/LibWasm/Types.h
index f55ab9330b..8dd52e8ac2 100644
--- a/Userland/Libraries/LibWasm/Types.h
+++ b/Userland/Libraries/LibWasm/Types.h
@@ -420,6 +420,9 @@ public:
 
     static ParseResult<Vector<Instruction>> parse(InputStream& stream, InstructionPointer& ip);
 
+    auto& opcode() const { return m_opcode; }
+    auto& arguments() const { return m_arguments; }
+
 private:
     OpCode m_opcode { 0 };
     // clang-format off
@@ -487,7 +490,7 @@ private:
 };
 
 class ImportSection {
-private:
+public:
     class Import {
     public:
         using ImportDesc = Variant<TypeIndex, TableType, MemoryType, GlobalType>;
@@ -553,7 +556,7 @@ private:
 };
 
 class TableSection {
-private:
+public:
     class Table {
     public:
         explicit Table(TableType type)
@@ -586,7 +589,7 @@ private:
 };
 
 class MemorySection {
-private:
+public:
     class Memory {
     public:
         explicit Memory(MemoryType type)
@@ -634,7 +637,7 @@ private:
 };
 
 class GlobalSection {
-private:
+public:
     class Global {
     public:
         explicit Global(GlobalType type, Expression expression)
@@ -672,6 +675,8 @@ private:
 class ExportSection {
 private:
     using ExportDesc = Variant<FunctionIndex, TableIndex, MemoryIndex, GlobalIndex>;
+
+public:
     class Export {
     public:
         explicit Export(String name, ExportDesc description)
@@ -690,7 +695,6 @@ private:
         ExportDesc m_description;
     };
 
-public:
     static constexpr u8 section_id = 7;
 
     explicit ExportSection(Vector<Export> entries)
@@ -707,7 +711,7 @@ private:
 };
 
 class StartSection {
-private:
+public:
     class StartFunction {
     public:
         explicit StartFunction(FunctionIndex index)
@@ -723,7 +727,6 @@ private:
         FunctionIndex m_index;
     };
 
-public:
     static constexpr u8 section_id = 8;
 
     explicit StartSection(StartFunction func)
@@ -740,7 +743,7 @@ private:
 };
 
 class ElementSection {
-private:
+public:
     class Element {
     public:
         explicit Element(TableIndex table, Expression expr, Vector<FunctionIndex> init)
@@ -762,7 +765,6 @@ private:
         Vector<FunctionIndex> m_init;
     };
 
-public:
     static constexpr u8 section_id = 9;
 
     explicit ElementSection(Element func)
@@ -817,7 +819,7 @@ private:
 };
 
 class CodeSection {
-private:
+public:
     class Code {
     public:
         explicit Code(u32 size, Func func)
@@ -836,7 +838,6 @@ private:
         Func m_func;
     };
 
-public:
     static constexpr u8 section_id = 10;
 
     explicit CodeSection(Vector<Code> funcs)
@@ -853,8 +854,9 @@ private:
 };
 
 class DataSection {
-private:
+public:
     class Data {
+    public:
         struct Passive {
             Vector<u8> init;
         };
@@ -865,7 +867,6 @@ private:
         };
         using Value = Variant<Passive, Active>;
 
-    public:
         explicit Data(Value value)
             : m_value(move(value))
         {
@@ -879,7 +880,6 @@ private:
         Value m_value;
     };
 
-public:
     static constexpr u8 section_id = 11;
 
     explicit DataSection(Vector<Data> data)
@@ -913,7 +913,7 @@ private:
 };
 
 class Module {
-private:
+public:
     class Function {
     public:
         explicit Function(TypeIndex type, Vector<ValueType> local_types, Expression body)
@@ -950,12 +950,13 @@ private:
     static constexpr Array<u8, 4> wasm_magic { 0, 'a', 's', 'm' };
     static constexpr Array<u8, 4> wasm_version { 1, 0, 0, 0 };
 
-public:
     explicit Module(Vector<AnySection> sections)
         : m_sections(move(sections))
     {
     }
 
+    auto& sections() const { return m_sections; }
+
     static ParseResult<Module> parse(InputStream& stream);
 
 private:
diff --git a/Userland/Utilities/wasm.cpp b/Userland/Utilities/wasm.cpp
index 4928272128..f583741aee 100644
--- a/Userland/Utilities/wasm.cpp
+++ b/Userland/Utilities/wasm.cpp
@@ -7,14 +7,17 @@
 #include <LibCore/ArgsParser.h>
 #include <LibCore/File.h>
 #include <LibCore/FileStream.h>
+#include <LibWasm/Printer/Printer.h>
 #include <LibWasm/Types.h>
 
 int main(int argc, char* argv[])
 {
     const char* filename = nullptr;
+    bool print = false;
 
     Core::ArgsParser parser;
     parser.add_positional_argument(filename, "File name to parse", "file");
+    parser.add_option(print, "Print the parsed module", "print", 'p');
     parser.parse(argc, argv);
 
     auto result = Core::File::open(filename, Core::OpenMode::ReadOnly);
@@ -31,5 +34,11 @@ int main(int argc, char* argv[])
         return 2;
     }
 
+    if (print) {
+        auto out_stream = Core::OutputFileStream::standard_output();
+        Wasm::Printer printer(out_stream);
+        printer.print(parse_result.value());
+    }
+
     return 0;
 }