From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Fri, 19 Apr 2024 02:47:55 +0200
Subject: Adding upstream version 124.0.1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 third_party/wasm2c/src/c-writer.cc | 5295 ++++++++++++++++++++++++++++++++++++
 1 file changed, 5295 insertions(+)
 create mode 100644 third_party/wasm2c/src/c-writer.cc

(limited to 'third_party/wasm2c/src/c-writer.cc')

diff --git a/third_party/wasm2c/src/c-writer.cc b/third_party/wasm2c/src/c-writer.cc
new file mode 100644
index 0000000000..2405c170ae
--- /dev/null
+++ b/third_party/wasm2c/src/c-writer.cc
@@ -0,0 +1,5295 @@
+/*
+ * Copyright 2017 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "wabt/c-writer.h"
+
+#include <cctype>
+#include <cinttypes>
+#include <iterator>
+#include <limits>
+#include <map>
+#include <set>
+#include <string_view>
+#include <vector>
+
+#include "wabt/cast.h"
+#include "wabt/common.h"
+#include "wabt/ir.h"
+#include "wabt/literal.h"
+#include "wabt/sha256.h"
+#include "wabt/stream.h"
+#include "wabt/string-util.h"
+
+#define INDENT_SIZE 2
+
+#define UNIMPLEMENTED(x) printf("unimplemented: %s\n", (x)), abort()
+
+// code to be inserted into the generated output
+extern const char* s_header_top;
+extern const char* s_header_bottom;
+extern const char* s_source_includes;
+extern const char* s_source_declarations;
+extern const char* s_simd_source_declarations;
+
+namespace wabt {
+
+namespace {
+
+struct Label {
+  Label(LabelType label_type,
+        const std::string& name,
+        const TypeVector& sig,
+        size_t type_stack_size,
+        size_t try_catch_stack_size,
+        bool used = false)
+      : label_type(label_type),
+        name(name),
+        sig(sig),
+        type_stack_size(type_stack_size),
+        try_catch_stack_size(try_catch_stack_size),
+        used(used) {}
+
+  bool HasValue() const { return !sig.empty(); }
+
+  LabelType label_type;
+  const std::string& name;
+  const TypeVector& sig;
+  size_t type_stack_size;
+  size_t try_catch_stack_size;
+  bool used = false;
+};
+
+struct LocalName {
+  explicit LocalName(const std::string& name) : name(name) {}
+  const std::string& name;
+};
+
+struct ParamName : LocalName {
+  using LocalName::LocalName;
+  ParamName(const Var& var) : LocalName(var.name()) {}
+};
+
+struct LabelName : LocalName {
+  using LocalName::LocalName;
+};
+
+struct GlobalName {
+  GlobalName(ModuleFieldType type, const std::string& name)
+      : type(type), name(name) {}
+  ModuleFieldType type;
+  const std::string& name;
+};
+
+struct ExternalPtr : GlobalName {
+  using GlobalName::GlobalName;
+};
+
+struct ExternalRef : GlobalName {
+  using GlobalName::GlobalName;
+};
+
+struct ExternalInstancePtr : GlobalName {
+  using GlobalName::GlobalName;
+};
+
+struct ExternalInstanceRef : GlobalName {
+  using GlobalName::GlobalName;
+};
+
+struct GotoLabel {
+  explicit GotoLabel(const Var& var) : var(var) {}
+  const Var& var;
+};
+
+struct LabelDecl {
+  explicit LabelDecl(const std::string& name) : name(name) {}
+  std::string name;
+};
+
+struct GlobalInstanceVar {
+  explicit GlobalInstanceVar(const Var& var) : var(var) {}
+  const Var& var;
+};
+
+struct StackVar {
+  explicit StackVar(Index index, Type type = Type::Any)
+      : index(index), type(type) {}
+  Index index;
+  Type type;
+};
+
+struct TypeEnum {
+  explicit TypeEnum(Type type) : type(type) {}
+  Type type;
+};
+
+struct SignedType {
+  explicit SignedType(Type type) : type(type) {}
+  Type type;
+};
+
+struct ResultType {
+  explicit ResultType(const TypeVector& types) : types(types) {}
+  const TypeVector& types;
+};
+
+struct TryCatchLabel {
+  TryCatchLabel(const std::string& name, size_t try_catch_stack_size)
+      : name(name), try_catch_stack_size(try_catch_stack_size), used(false) {}
+  std::string name;
+  size_t try_catch_stack_size;
+  bool used;
+};
+
+struct FuncTypeExpr {
+  const FuncType* func_type;
+  FuncTypeExpr(const FuncType* f) : func_type(f) {}
+};
+
+struct Newline {};
+struct OpenBrace {};
+struct CloseBrace {};
+
+int GetShiftMask(Type type) {
+  // clang-format off
+  switch (type) {
+    case Type::I32: return 31;
+    case Type::I64: return 63;
+    default: WABT_UNREACHABLE; return 0;
+  }
+  // clang-format on
+}
+
+/*
+ * This function is the default behavior for name_to_output_file_index_. For
+ * single .c output, this function returns a vector filled with 0. For multiple
+ * .c outputs, this function sorts all non-imported functions in the module by
+ * their names, and then divides all non-imported functions into equal-sized
+ * buckets (# of non-imported functions / # of .c outputs) based on the sorting.
+ */
+static std::vector<size_t> default_name_to_output_file_index(
+    std::vector<Func*>::const_iterator func_begin,
+    std::vector<Func*>::const_iterator func_end,
+    size_t num_imports,
+    size_t num_streams) {
+  std::vector<size_t> result;
+  result.resize(std::distance(func_begin, func_end));
+  if (num_streams == 1) {
+    return result;
+  }
+
+  std::map<std::string, Index> sorted_functions;
+  size_t non_imported_funcs = result.size() - num_imports;
+  size_t bucket_size = non_imported_funcs / num_streams +
+                       (non_imported_funcs % num_streams ? 1 : 0);
+  Index func_index = 0;
+  for (auto func = func_begin; func != func_end; func++) {
+    sorted_functions.insert({(*func)->name, func_index});
+    ++func_index;
+  }
+  Index sorted_func_index = 0;
+  for (const auto& [func_name, index] : sorted_functions) {
+    bool is_import = index < num_imports;
+    if (!is_import) {
+      result.at(index) = sorted_func_index / bucket_size;
+      ++sorted_func_index;
+    }
+  }
+  return result;
+}
+
+class CWriter {
+ public:
+  CWriter(std::vector<Stream*>&& c_streams,
+          Stream* h_stream,
+          Stream* h_impl_stream,
+          const char* header_name,
+          const char* header_impl_name,
+          const WriteCOptions& options)
+      : options_(options),
+        c_streams_(std::move(c_streams)),
+        h_stream_(h_stream),
+        h_impl_stream_(h_impl_stream),
+        header_name_(header_name),
+        header_impl_name_(header_impl_name) {
+    module_prefix_ = MangleModuleName(options_.module_name);
+    if (c_streams_.size() != 1 && options.name_to_output_file_index) {
+      name_to_output_file_index_ = options.name_to_output_file_index;
+    } else {
+      name_to_output_file_index_ = default_name_to_output_file_index;
+    }
+  }
+
+  Result WriteModule(const Module&);
+
+ private:
+  using SymbolSet = std::set<std::string>;
+  using SymbolMap = std::map<std::string, std::string>;
+  using StackTypePair = std::pair<Index, Type>;
+  using StackVarSymbolMap = std::map<StackTypePair, std::string>;
+
+  void WriteCHeader();
+  void WriteCSource();
+
+  size_t MarkTypeStack() const;
+  void ResetTypeStack(size_t mark);
+  Type StackType(Index) const;
+  void PushType(Type);
+  void PushTypes(const TypeVector&);
+  void DropTypes(size_t count);
+
+  void PushLabel(LabelType,
+                 const std::string& name,
+                 const FuncSignature&,
+                 bool used = false);
+  const Label* FindLabel(const Var& var, bool mark_used = true);
+  bool IsTopLabelUsed() const;
+  void PopLabel();
+
+  static constexpr char MangleType(Type);
+  static constexpr char MangleField(ModuleFieldType);
+  static std::string MangleMultivalueTypes(const TypeVector&);
+  static std::string MangleTagTypes(const TypeVector&);
+  static std::string Mangle(std::string_view name, bool double_underscores);
+  static std::string MangleName(std::string_view);
+  static std::string MangleModuleName(std::string_view);
+  std::string ExportName(std::string_view module_name,
+                         std::string_view export_name);
+  std::string ExportName(std::string_view export_name);
+  std::string ModuleInstanceTypeName() const;
+  static std::string ModuleInstanceTypeName(std::string_view module_name);
+  void ClaimName(SymbolSet& set,
+                 SymbolMap& map,
+                 char type_suffix,
+                 std::string_view wasm_name,
+                 const std::string& c_name);
+  std::string FindUniqueName(SymbolSet& set, std::string_view proposed_name);
+  std::string ClaimUniqueName(SymbolSet& set,
+                              SymbolMap& map,
+                              char type_suffix,
+                              std::string_view wasm_name,
+                              const std::string& proposed_c_name);
+  void DefineImportName(const Import* import,
+                        std::string_view module_name,
+                        std::string_view field_name);
+  void ReserveExportNames();
+  void ReserveExportName(std::string_view);
+  std::string DefineImportedModuleInstanceName(std::string_view name);
+  std::string DefineInstanceMemberName(ModuleFieldType, std::string_view);
+  std::string DefineGlobalScopeName(ModuleFieldType, std::string_view);
+  std::string DefineLocalScopeName(std::string_view name, bool is_label);
+  std::string DefineParamName(std::string_view);
+  std::string DefineLabelName(std::string_view);
+  std::string DefineStackVarName(Index, Type, std::string_view);
+
+  static void SerializeFuncType(const FuncType&, std::string&);
+
+  std::string GetGlobalName(ModuleFieldType, const std::string&) const;
+  std::string GetLocalName(const std::string&, bool is_label) const;
+
+  void Indent(int size = INDENT_SIZE);
+  void Dedent(int size = INDENT_SIZE);
+  void WriteIndent();
+  void WriteData(const char* src, size_t size);
+  void Writef(const char* format, ...);
+
+  template <typename T, typename U, typename... Args>
+  void Write(T&& t, U&& u, Args&&... args) {
+    Write(std::forward<T>(t));
+    Write(std::forward<U>(u));
+    Write(std::forward<Args>(args)...);
+  }
+
+  static const char* GetReferenceTypeName(const Type& type);
+  static const char* GetReferenceNullValue(const Type& type);
+  static const char* GetCTypeName(const Type& type);
+
+  const char* InternalSymbolScope() const;
+
+  enum class CWriterPhase {
+    Declarations,
+    Definitions,
+  };
+
+  void Write() {}
+  void Write(Newline);
+  void Write(OpenBrace);
+  void Write(CloseBrace);
+  void Write(uint64_t);
+  void Write(std::string_view);
+  void Write(const ParamName&);
+  void Write(const LabelName&);
+  void Write(const GlobalName&);
+  void Write(const ExternalPtr&);
+  void Write(const ExternalRef&);
+  void Write(const ExternalInstancePtr&);
+  void Write(const ExternalInstanceRef&);
+  void Write(Type);
+  void Write(SignedType);
+  void Write(TypeEnum);
+  void Write(const GotoLabel&);
+  void Write(const LabelDecl&);
+  void Write(const GlobalInstanceVar&);
+  void Write(const StackVar&);
+  void Write(const ResultType&);
+  void Write(const Const&);
+  void WriteInitExpr(const ExprList&);
+  void WriteInitExprTerminal(const Expr*);
+  std::string GenerateHeaderGuard() const;
+  void WriteSourceTop();
+  void WriteMultiCTop();
+  void WriteMultiCTopEmpty();
+  void WriteMultivalueTypes();
+  void WriteTagTypes();
+  void WriteFuncTypeDecls();
+  void WriteFuncTypes();
+  void Write(const FuncTypeExpr&);
+  void WriteTagDecls();
+  void WriteTags();
+  void ComputeUniqueImports();
+  void BeginInstance();
+  void WriteImports();
+  void WriteFuncDeclarations();
+  void WriteFuncDeclaration(const FuncDeclaration&, const std::string&);
+  void WriteImportFuncDeclaration(const FuncDeclaration&,
+                                  const std::string& module_name,
+                                  const std::string&);
+  void WriteCallIndirectFuncDeclaration(const FuncDeclaration&,
+                                        const std::string&);
+  void ComputeSimdScope();
+  void WriteHeaderIncludes();
+  void WriteV128Decl();
+  void WriteModuleInstance();
+  void WriteGlobals();
+  void WriteGlobal(const Global&, const std::string&);
+  void WriteGlobalPtr(const Global&, const std::string&);
+  void WriteMemories();
+  void WriteMemory(const std::string&);
+  void WriteMemoryPtr(const std::string&);
+  void WriteTables();
+  void WriteTable(const std::string&, const wabt::Type&);
+  void WriteTablePtr(const std::string&, const Table&);
+  void WriteTableType(const wabt::Type&);
+  void WriteDataInstances();
+  void WriteElemInstances();
+  void WriteGlobalInitializers();
+  void WriteDataInitializerDecls();
+  void WriteDataInitializers();
+  void WriteElemInitializerDecls();
+  void WriteElemInitializers();
+  void WriteElemTableInit(bool, const ElemSegment*, const Table*);
+  void WriteExports(CWriterPhase);
+  void WriteInitDecl();
+  void WriteFreeDecl();
+  void WriteGetFuncTypeDecl();
+  void WriteInit();
+  void WriteFree();
+  void WriteGetFuncType();
+  void WriteInitInstanceImport();
+  void WriteImportProperties(CWriterPhase);
+  void WriteFuncs();
+  void Write(const Func&);
+  void WriteParamsAndLocals();
+  void WriteParams(const std::vector<std::string>& index_to_name);
+  void WriteParamSymbols(const std::vector<std::string>& index_to_name);
+  void WriteParamTypes(const FuncDeclaration& decl);
+  void WriteLocals(const std::vector<std::string>& index_to_name);
+  void WriteStackVarDeclarations();
+  void Write(const ExprList&);
+
+  enum class AssignOp {
+    Disallowed,
+    Allowed,
+  };
+
+  void WriteSimpleUnaryExpr(Opcode, const char* op);
+  void WriteInfixBinaryExpr(Opcode,
+                            const char* op,
+                            AssignOp = AssignOp::Allowed);
+  void WritePrefixBinaryExpr(Opcode, const char* op);
+  void WriteSignedBinaryExpr(Opcode, const char* op);
+  void Write(const BinaryExpr&);
+  void Write(const CompareExpr&);
+  void Write(const ConvertExpr&);
+  void Write(const LoadExpr&);
+  void Write(const StoreExpr&);
+  void Write(const UnaryExpr&);
+  void Write(const TernaryExpr&);
+  void Write(const SimdLaneOpExpr&);
+  void Write(const SimdLoadLaneExpr&);
+  void Write(const SimdStoreLaneExpr&);
+  void Write(const SimdShuffleOpExpr&);
+  void Write(const LoadSplatExpr&);
+  void Write(const LoadZeroExpr&);
+  void Write(const Block&);
+
+  size_t BeginTry(const TryExpr& tryexpr);
+  void WriteTryCatch(const TryExpr& tryexpr);
+  void WriteTryDelegate(const TryExpr& tryexpr);
+  void Write(const Catch& c);
+  void WriteThrow();
+
+  void PushTryCatch(const std::string& name);
+  void PopTryCatch();
+
+  void PushFuncSection(std::string_view include_condition = "");
+
+  const WriteCOptions& options_;
+  const Module* module_ = nullptr;
+  const Func* func_ = nullptr;
+  Stream* stream_ = nullptr;
+  std::vector<Stream*> c_streams_;
+  Stream* h_stream_ = nullptr;
+  Stream* h_impl_stream_ = nullptr;
+  std::string header_name_;
+  std::string header_impl_name_;
+  Result result_ = Result::Ok;
+  int indent_ = 0;
+  bool should_write_indent_next_ = false;
+  int consecutive_newline_count_ = 0;
+
+  SymbolMap global_sym_map_;
+  SymbolMap local_sym_map_;
+  SymbolMap import_module_sym_map_;
+  StackVarSymbolMap stack_var_sym_map_;
+  SymbolSet global_syms_;
+  SymbolSet local_syms_;
+  SymbolSet import_syms_;
+  TypeVector type_stack_;
+  std::vector<Label> label_stack_;
+  std::vector<TryCatchLabel> try_catch_stack_;
+  std::string module_prefix_;
+
+  std::vector<const Import*> unique_imports_;
+  SymbolSet import_module_set_;       // modules that are imported from
+  SymbolSet import_func_module_set_;  // modules that funcs are imported from
+
+  std::vector<std::pair<std::string, MemoryStream>> func_sections_;
+  SymbolSet func_includes_;
+
+  std::vector<std::string> unique_func_type_names_;
+
+  std::function<std::vector<size_t>(std::vector<Func*>::const_iterator,
+                                    std::vector<Func*>::const_iterator,
+                                    size_t,
+                                    size_t)>
+      name_to_output_file_index_;
+
+  bool simd_used_in_header_;
+};
+
+// TODO: if WABT begins supporting debug names for labels,
+// will need to avoid conflict between a label named "$Bfunc" and
+// the implicit func label
+static constexpr char kImplicitFuncLabel[] = "$Bfunc";
+
+// These should be greater than any ModuleFieldType (used for MangleField).
+static constexpr char kParamSuffix =
+    'a' + static_cast<char>(ModuleFieldType::Tag) + 1;
+static constexpr char kLabelSuffix = kParamSuffix + 1;
+
+static constexpr char kGlobalSymbolPrefix[] = "w2c_";
+static constexpr char kLocalSymbolPrefix[] = "var_";
+static constexpr char kAdminSymbolPrefix[] = "wasm2c_";
+
+size_t CWriter::MarkTypeStack() const {
+  return type_stack_.size();
+}
+
+void CWriter::ResetTypeStack(size_t mark) {
+  assert(mark <= type_stack_.size());
+  type_stack_.erase(type_stack_.begin() + mark, type_stack_.end());
+}
+
+Type CWriter::StackType(Index index) const {
+  assert(index < type_stack_.size());
+  return *(type_stack_.rbegin() + index);
+}
+
+void CWriter::PushType(Type type) {
+  type_stack_.push_back(type);
+}
+
+void CWriter::PushTypes(const TypeVector& types) {
+  type_stack_.insert(type_stack_.end(), types.begin(), types.end());
+}
+
+void CWriter::DropTypes(size_t count) {
+  assert(count <= type_stack_.size());
+  type_stack_.erase(type_stack_.end() - count, type_stack_.end());
+}
+
+void CWriter::PushLabel(LabelType label_type,
+                        const std::string& name,
+                        const FuncSignature& sig,
+                        bool used) {
+  if (label_type == LabelType::Loop)
+    label_stack_.emplace_back(label_type, name, sig.param_types,
+                              type_stack_.size(), try_catch_stack_.size(),
+                              used);
+  else
+    label_stack_.emplace_back(label_type, name, sig.result_types,
+                              type_stack_.size(), try_catch_stack_.size(),
+                              used);
+}
+
+const Label* CWriter::FindLabel(const Var& var, bool mark_used) {
+  Label* label = nullptr;
+
+  if (var.is_index()) {
+    // We've generated names for all labels, so we should only be using an
+    // index when branching to the implicit function label, which can't be
+    // named.
+    assert(var.index() + 1 == label_stack_.size());
+    label = &label_stack_[0];
+  } else {
+    assert(var.is_name());
+    for (Index i = label_stack_.size(); i > 0; --i) {
+      label = &label_stack_[i - 1];
+      if (label->name == var.name())
+        break;
+    }
+  }
+
+  assert(label);
+  if (mark_used) {
+    label->used = true;
+  }
+  return label;
+}
+
+bool CWriter::IsTopLabelUsed() const {
+  assert(!label_stack_.empty());
+  return label_stack_.back().used;
+}
+
+void CWriter::PopLabel() {
+  label_stack_.pop_back();
+}
+
+// static
+constexpr char CWriter::MangleType(Type type) {
+  // clang-format off
+  switch (type) {
+    case Type::I32: return 'i';
+    case Type::I64: return 'j';
+    case Type::F32: return 'f';
+    case Type::F64: return 'd';
+    case Type::V128: return 'o';
+    case Type::FuncRef: return 'r';
+    case Type::ExternRef: return 'e';
+    default:
+      WABT_UNREACHABLE;
+  }
+  // clang-format on
+}
+
+// static
+constexpr char CWriter::MangleField(ModuleFieldType type) {
+  assert(static_cast<std::underlying_type<ModuleFieldType>::type>(type) <
+         std::numeric_limits<char>::max());
+  return 'a' + static_cast<char>(type);
+}
+
+// remove risky characters for pasting into a C-style comment
+static std::string SanitizeForComment(std::string_view str) {
+  std::string result;
+
+  for (const uint8_t ch : str) {
+    // escape control chars, DEL, >7-bit chars, trigraphs, and end of comment
+    if (ch < ' ' || ch > '~' || ch == '?' || ch == '/') {
+      result += "\\" + StringPrintf("%02X", ch);
+    } else {
+      result += ch;
+    }
+  }
+
+  return result;
+}
+
+// static
+std::string CWriter::MangleMultivalueTypes(const TypeVector& types) {
+  assert(types.size() >= 2);
+  std::string result = "wasm_multi_";
+  for (auto type : types) {
+    result += MangleType(type);
+  }
+  return result;
+}
+
+// static
+std::string CWriter::MangleTagTypes(const TypeVector& types) {
+  assert(types.size() >= 2);
+  std::string result = "wasm_tag_";
+  for (auto type : types) {
+    result += MangleType(type);
+  }
+  return result;
+}
+
+/* The C symbol for an export from this module. */
+std::string CWriter::ExportName(std::string_view export_name) {
+  return kGlobalSymbolPrefix + module_prefix_ + '_' + MangleName(export_name);
+}
+
+/* The C symbol for an export from an arbitrary module. */
+// static
+std::string CWriter::ExportName(std::string_view module_name,
+                                std::string_view export_name) {
+  return kGlobalSymbolPrefix + MangleModuleName(module_name) + '_' +
+         MangleName(export_name);
+}
+
+/* The type name of an instance of this module. */
+std::string CWriter::ModuleInstanceTypeName() const {
+  return kGlobalSymbolPrefix + module_prefix_;
+}
+
+/* The type name of an instance of an arbitrary module. */
+// static
+std::string CWriter::ModuleInstanceTypeName(std::string_view module_name) {
+  return kGlobalSymbolPrefix + MangleModuleName(module_name);
+}
+
+/*
+ * Hardcoded "C"-locale versions of isalpha/isdigit/isalnum/isxdigit for use
+ * in CWriter::Mangle(). We don't use the standard isalpha/isdigit/isalnum
+ * because the caller might have changed the current locale.
+ */
+static bool internal_isalpha(uint8_t ch) {
+  return (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z');
+}
+
+static bool internal_isdigit(uint8_t ch) {
+  return (ch >= '0' && ch <= '9');
+}
+
+static bool internal_isalnum(uint8_t ch) {
+  return internal_isalpha(ch) || internal_isdigit(ch);
+}
+
+static bool internal_ishexdigit(uint8_t ch) {
+  return internal_isdigit(ch) || (ch >= 'A' && ch <= 'F');  // capitals only
+}
+
+// static
+std::string CWriter::Mangle(std::string_view name, bool double_underscores) {
+  /*
+   * Name mangling transforms arbitrary Wasm names into "safe" C names
+   * in a deterministic way. To avoid collisions, distinct Wasm names must be
+   * transformed into distinct C names.
+   *
+   * The rules implemented here are:
+   * 1) any hex digit ('A' through 'F') that follows the sequence "0x"
+   *    is escaped
+   * 2) any underscore at the beginning, at the end, or following another
+   *    underscore, is escaped
+   * 3) if double_underscores is set, underscores are replaced with
+   *    two underscores.
+   * 4) otherwise, any alphanumeric character is kept as-is,
+   *    and any other character is escaped
+   *
+   * "Escaped" means the character is represented with the sequence "0xAB",
+   * where A B are hex digits ('0'-'9' or 'A'-'F') representing the character's
+   * numeric value.
+   *
+   * Module names are mangled with double_underscores=true to prevent
+   * collisions between, e.g., a module "alfa" with export
+   * "bravo_charlie" vs. a module "alfa_bravo" with export "charlie".
+   */
+
+  enum State { Any, Zero, ZeroX, ZeroXHexDigit } state{Any};
+  bool last_was_underscore = false;
+
+  std::string result;
+  auto append_escaped = [&](const uint8_t ch) {
+    result += "0x" + StringPrintf("%02X", ch);
+    last_was_underscore = false;
+    state = Any;
+  };
+
+  auto append_verbatim = [&](const uint8_t ch) {
+    result += ch;
+    last_was_underscore = (ch == '_');
+  };
+
+  for (auto it = name.begin(); it != name.end(); ++it) {
+    const uint8_t ch = *it;
+    switch (state) {
+      case Any:
+        state = (ch == '0') ? Zero : Any;
+        break;
+      case Zero:
+        state = (ch == 'x') ? ZeroX : Any;
+        break;
+      case ZeroX:
+        state = internal_ishexdigit(ch) ? ZeroXHexDigit : Any;
+        break;
+      case ZeroXHexDigit:
+        WABT_UNREACHABLE;
+        break;
+    }
+
+    /* rule 1 */
+    if (state == ZeroXHexDigit) {
+      append_escaped(ch);
+      continue;
+    }
+
+    /* rule 2 */
+    if ((ch == '_') && ((it == name.begin()) || (std::next(it) == name.end()) ||
+                        last_was_underscore)) {
+      append_escaped(ch);
+      continue;
+    }
+
+    /* rule 3 */
+    if (double_underscores && ch == '_') {
+      append_verbatim(ch);
+      append_verbatim(ch);
+      continue;
+    }
+
+    /* rule 4 */
+    if (internal_isalnum(ch) || (ch == '_')) {
+      append_verbatim(ch);
+    } else {
+      append_escaped(ch);
+    }
+  }
+
+  return result;
+}
+
+// static
+std::string CWriter::MangleName(std::string_view name) {
+  return Mangle(name, false);
+}
+
+// static
+std::string CWriter::MangleModuleName(std::string_view name) {
+  return Mangle(name, true);
+}
+
+/*
+ * Allocate a C symbol (must be unused) in the SymbolSet,
+ * and a mapping from the Wasm name (tagged with
+ * the index space of the name) to that C symbol.
+ */
+void CWriter::ClaimName(SymbolSet& set,
+                        SymbolMap& map,
+                        char type_suffix,
+                        std::string_view wasm_name,
+                        const std::string& c_name) {
+  const std::string type_tagged_wasm_name =
+      std::string(wasm_name) + type_suffix;
+
+  [[maybe_unused]] bool success;
+  success = set.insert(c_name).second;
+  assert(success);
+
+  success = map.emplace(type_tagged_wasm_name, c_name).second;
+  assert(success);
+}
+
+/*
+ * Make a proposed C symbol unique in a given symbol set by appending
+ * an integer to the symbol if necessary.
+ */
+std::string CWriter::FindUniqueName(SymbolSet& set,
+                                    std::string_view proposed_name) {
+  std::string unique{proposed_name};
+  if (set.find(unique) != set.end()) {
+    std::string base = unique + "_";
+    size_t count = 0;
+    do {
+      unique = base + std::to_string(count++);
+    } while (set.find(unique) != set.end());
+  }
+  return unique;
+}
+
+/*
+ * Find a unique C symbol in the symbol set and claim it (mapping the
+ * type-tagged Wasm name to it).
+ */
+std::string CWriter::ClaimUniqueName(SymbolSet& set,
+                                     SymbolMap& map,
+                                     char type_suffix,
+                                     std::string_view wasm_name,
+                                     const std::string& proposed_c_name) {
+  const std::string unique = FindUniqueName(set, proposed_c_name);
+  ClaimName(set, map, type_suffix, wasm_name, unique);
+  return unique;
+}
+
+std::string_view StripLeadingDollar(std::string_view name) {
+  assert(!name.empty());
+  assert(name.front() == '$');
+  name.remove_prefix(1);
+  return name;
+}
+
+void CWriter::DefineImportName(const Import* import,
+                               std::string_view module,
+                               std::string_view field_name) {
+  std::string name;
+  ModuleFieldType type{};
+
+  switch (import->kind()) {
+    case ExternalKind::Func:
+      type = ModuleFieldType::Func;
+      name = cast<FuncImport>(import)->func.name;
+      break;
+    case ExternalKind::Tag:
+      type = ModuleFieldType::Tag;
+      name = cast<TagImport>(import)->tag.name;
+      break;
+    case ExternalKind::Global:
+      type = ModuleFieldType::Global;
+      name = cast<GlobalImport>(import)->global.name;
+      break;
+    case ExternalKind::Memory:
+      type = ModuleFieldType::Memory;
+      name = cast<MemoryImport>(import)->memory.name;
+      break;
+    case ExternalKind::Table:
+      type = ModuleFieldType::Table;
+      name = cast<TableImport>(import)->table.name;
+      break;
+  }
+
+  import_syms_.insert(name);
+  import_module_sym_map_.emplace(name, import->module_name);
+
+  const std::string mangled = ExportName(module, field_name);
+  global_syms_.erase(mangled);  // duplicate imports are allowed
+  ClaimName(global_syms_, global_sym_map_, MangleField(type), name, mangled);
+}
+
+/*
+ * Reserve a C symbol for the public name of a module's export.  The
+ * format of these is "w2c_" + the module prefix + "_" + the mangled
+ * export name. Reserving the symbol prevents internal functions and
+ * other names from shadowing/overlapping the exports.
+ */
+void CWriter::ReserveExportName(std::string_view name) {
+  ClaimName(global_syms_, global_sym_map_, MangleField(ModuleFieldType::Export),
+            name, ExportName(name));
+}
+
+/*
+ * Names for functions, function types, tags, and segments are globally unique
+ * across modules (formatted the same as an export, as "w2c_" + module prefix +
+ * "_" + the name, made unique if necessary).
+ */
+std::string CWriter::DefineGlobalScopeName(ModuleFieldType type,
+                                           std::string_view name) {
+  return ClaimUniqueName(global_syms_, global_sym_map_, MangleField(type), name,
+                         ExportName(StripLeadingDollar(name)));
+}
+
+std::string CWriter::GetGlobalName(ModuleFieldType type,
+                                   const std::string& name) const {
+  std::string mangled = name + MangleField(type);
+  assert(global_sym_map_.count(mangled) == 1);
+  return global_sym_map_.at(mangled);
+}
+
+/* Names for params, locals, and stack vars are formatted as "var_" + name. */
+std::string CWriter::DefineLocalScopeName(std::string_view name,
+                                          bool is_label) {
+  return ClaimUniqueName(
+      local_syms_, local_sym_map_, is_label ? kLabelSuffix : kParamSuffix, name,
+      kLocalSymbolPrefix + MangleName(StripLeadingDollar(name)));
+}
+
+std::string CWriter::GetLocalName(const std::string& name,
+                                  bool is_label) const {
+  std::string mangled = name + (is_label ? kLabelSuffix : kParamSuffix);
+  assert(local_sym_map_.count(mangled) == 1);
+  return local_sym_map_.at(mangled);
+}
+
+std::string CWriter::DefineParamName(std::string_view name) {
+  return DefineLocalScopeName(name, false);
+}
+
+std::string CWriter::DefineLabelName(std::string_view name) {
+  return DefineLocalScopeName(name, true);
+}
+
+std::string CWriter::DefineStackVarName(Index index,
+                                        Type type,
+                                        std::string_view name) {
+  std::string unique =
+      FindUniqueName(local_syms_, kLocalSymbolPrefix + MangleName(name));
+  StackTypePair stp = {index, type};
+  [[maybe_unused]] bool success =
+      stack_var_sym_map_.emplace(stp, unique).second;
+  assert(success);
+  return unique;
+}
+
+/*
+ * Members of the module instance (globals, tables, and memories) are formatted
+ * as "w2c_" + the mangled name of the element (made unique if necessary).
+ */
+std::string CWriter::DefineInstanceMemberName(ModuleFieldType type,
+                                              std::string_view name) {
+  return ClaimUniqueName(
+      global_syms_, global_sym_map_, MangleField(type), name,
+      kGlobalSymbolPrefix + MangleName(StripLeadingDollar(name)));
+}
+
+/*
+ * The name of a module-instance member that points to the originating
+ * instance of an imported function is formatted as "w2c_" + originating
+ * module prefix + "_instance".
+ */
+std::string CWriter::DefineImportedModuleInstanceName(std::string_view name) {
+  return ClaimUniqueName(global_syms_, global_sym_map_,
+                         MangleField(ModuleFieldType::Import), name,
+                         ExportName(name, "instance"));
+}
+
+void CWriter::Indent(int size) {
+  indent_ += size;
+}
+
+void CWriter::Dedent(int size) {
+  indent_ -= size;
+  assert(indent_ >= 0);
+}
+
+void CWriter::WriteIndent() {
+  static char s_indent[] =
+      "                                                                       "
+      "                                                                       ";
+  static size_t s_indent_len = sizeof(s_indent) - 1;
+  size_t to_write = indent_;
+  while (to_write >= s_indent_len) {
+    stream_->WriteData(s_indent, s_indent_len);
+    to_write -= s_indent_len;
+  }
+  if (to_write > 0) {
+    stream_->WriteData(s_indent, to_write);
+  }
+}
+
+void CWriter::WriteData(const char* src, size_t size) {
+  if (should_write_indent_next_) {
+    WriteIndent();
+    should_write_indent_next_ = false;
+  }
+  if (size > 0 && src[0] != '\n') {
+    consecutive_newline_count_ = 0;
+  }
+  stream_->WriteData(src, size);
+}
+
+void WABT_PRINTF_FORMAT(2, 3) CWriter::Writef(const char* format, ...) {
+  WABT_SNPRINTF_ALLOCA(buffer, length, format);
+  WriteData(buffer, length);
+}
+
+void CWriter::Write(Newline) {
+  // Allow maximum one blank line between sections
+  if (consecutive_newline_count_ < 2) {
+    Write("\n");
+    consecutive_newline_count_++;
+  }
+  should_write_indent_next_ = true;
+}
+
+void CWriter::Write(OpenBrace) {
+  Write("{");
+  Indent();
+  Write(Newline());
+}
+
+void CWriter::Write(CloseBrace) {
+  Dedent();
+  Write("}");
+}
+
+void CWriter::Write(uint64_t val) {
+  Writef("%" PRIu64, val);
+}
+
+void CWriter::Write(std::string_view s) {
+  WriteData(s.data(), s.size());
+}
+
+void CWriter::Write(const ParamName& name) {
+  Write(GetLocalName(name.name, false));
+}
+
+void CWriter::Write(const LabelName& name) {
+  Write(GetLocalName(name.name, true));
+}
+
+void CWriter::Write(const GlobalName& name) {
+  Write(GetGlobalName(name.type, name.name));
+}
+
+void CWriter::Write(const ExternalPtr& name) {
+  bool is_import = import_syms_.count(name.name) != 0;
+  if (!is_import) {
+    Write("&");
+  }
+  Write(GlobalName(name));
+}
+
+void CWriter::Write(const ExternalInstancePtr& name) {
+  bool is_import = import_syms_.count(name.name) != 0;
+  if (!is_import) {
+    Write("&");
+  }
+  Write("instance->", GlobalName(name));
+}
+
+void CWriter::Write(const ExternalRef& name) {
+  bool is_import = import_syms_.count(name.name) != 0;
+  if (is_import) {
+    Write("(*", GlobalName(name), ")");
+  } else {
+    Write(GlobalName(name));
+  }
+}
+
+void CWriter::Write(const ExternalInstanceRef& name) {
+  bool is_import = import_syms_.count(name.name) != 0;
+  if (is_import) {
+    Write("(*instance->", GlobalName(name), ")");
+  } else {
+    Write("instance->", GlobalName(name));
+  }
+}
+
+void CWriter::Write(const GotoLabel& goto_label) {
+  const Label* label = FindLabel(goto_label.var);
+  if (label->HasValue()) {
+    size_t amount = label->sig.size();
+    assert(type_stack_.size() >= label->type_stack_size);
+    assert(type_stack_.size() >= amount);
+    assert(type_stack_.size() - amount >= label->type_stack_size);
+    Index offset = type_stack_.size() - label->type_stack_size - amount;
+    if (offset != 0) {
+      for (Index i = 0; i < amount; ++i) {
+        Write(StackVar(amount - i - 1 + offset, label->sig[i]), " = ",
+              StackVar(amount - i - 1), "; ");
+      }
+    }
+  }
+
+  assert(try_catch_stack_.size() >= label->try_catch_stack_size);
+
+  if (try_catch_stack_.size() != label->try_catch_stack_size) {
+    const std::string& name =
+        try_catch_stack_.at(label->try_catch_stack_size).name;
+
+    Write("wasm_rt_set_unwind_target(", name, "_outer_target);", Newline());
+  }
+
+  if (goto_label.var.is_name()) {
+    Write("goto ", LabelName(goto_label.var.name()), ";");
+  } else {
+    // We've generated names for all labels, so we should only be using an
+    // index when branching to the implicit function label, which can't be
+    // named.
+    Write("goto ", LabelName(kImplicitFuncLabel), ";");
+  }
+}
+
+void CWriter::Write(const LabelDecl& label) {
+  if (IsTopLabelUsed())
+    Write(label.name, ":;", Newline());
+}
+
+void CWriter::Write(const GlobalInstanceVar& var) {
+  assert(var.var.is_name());
+  Write(ExternalInstanceRef(ModuleFieldType::Global, var.var.name()));
+}
+
+void CWriter::Write(const StackVar& sv) {
+  Index index = type_stack_.size() - 1 - sv.index;
+  Type type = sv.type;
+  if (type == Type::Any) {
+    assert(index < type_stack_.size());
+    type = type_stack_[index];
+  }
+
+  StackTypePair stp = {index, type};
+  auto iter = stack_var_sym_map_.find(stp);
+  if (iter == stack_var_sym_map_.end()) {
+    std::string name = MangleType(type) + std::to_string(index);
+    Write(DefineStackVarName(index, type, name));
+  } else {
+    Write(iter->second);
+  }
+}
+
+// static
+const char* CWriter::GetCTypeName(const Type& type) {
+  // clang-format off
+  switch (type) {
+  case Type::I32: return "u32";
+  case Type::I64: return "u64";
+  case Type::F32: return "f32";
+  case Type::F64: return "f64";
+  case Type::V128: return "v128";
+  case Type::FuncRef: return "wasm_rt_funcref_t";
+  case Type::ExternRef: return "wasm_rt_externref_t";
+    default:
+      WABT_UNREACHABLE;
+  }
+  // clang-format on
+}
+
+void CWriter::Write(Type type) {
+  Write(GetCTypeName(type));
+}
+
+void CWriter::Write(TypeEnum type) {
+  // clang-format off
+  switch (type.type) {
+    case Type::I32: Write("WASM_RT_I32"); break;
+    case Type::I64: Write("WASM_RT_I64"); break;
+    case Type::F32: Write("WASM_RT_F32"); break;
+    case Type::F64: Write("WASM_RT_F64"); break;
+    case Type::V128: Write("WASM_RT_V128"); break;
+    case Type::FuncRef: Write("WASM_RT_FUNCREF"); break;
+    case Type::ExternRef: Write("WASM_RT_EXTERNREF"); break;
+    default:
+      WABT_UNREACHABLE;
+  }
+  // clang-format on
+}
+
+void CWriter::Write(SignedType type) {
+  // clang-format off
+  switch (type.type) {
+    case Type::I32: Write("s32"); break;
+    case Type::I64: Write("s64"); break;
+    default:
+      WABT_UNREACHABLE;
+  }
+  // clang-format on
+}
+
+void CWriter::Write(const ResultType& rt) {
+  if (rt.types.empty()) {
+    Write("void");
+  } else if (rt.types.size() == 1) {
+    Write(rt.types[0]);
+  } else {
+    Write("struct ", MangleMultivalueTypes(rt.types));
+  }
+}
+
+void CWriter::Write(const Const& const_) {
+  switch (const_.type()) {
+    case Type::I32:
+      Writef("%uu", static_cast<int32_t>(const_.u32()));
+      break;
+
+    case Type::I64:
+      Writef("%" PRIu64 "ull", static_cast<int64_t>(const_.u64()));
+      break;
+
+    case Type::F32: {
+      uint32_t f32_bits = const_.f32_bits();
+      // TODO(binji): Share with similar float info in interp.cc and literal.cc
+      if ((f32_bits & 0x7f800000u) == 0x7f800000u) {
+        const char* sign = (f32_bits & 0x80000000) ? "-" : "";
+        uint32_t significand = f32_bits & 0x7fffffu;
+        if (significand == 0) {
+          // Infinity.
+          Writef("%sINFINITY", sign);
+        } else {
+          // Nan.
+          Writef("f32_reinterpret_i32(0x%08x) /* %snan:0x%06x */", f32_bits,
+                 sign, significand);
+        }
+      } else if (f32_bits == 0x80000000) {
+        // Negative zero. Special-cased so it isn't written as -0 below.
+        Writef("-0.f");
+      } else {
+        Writef("%.9g", Bitcast<float>(f32_bits));
+      }
+      break;
+    }
+
+    case Type::F64: {
+      uint64_t f64_bits = const_.f64_bits();
+      // TODO(binji): Share with similar float info in interp.cc and literal.cc
+      if ((f64_bits & 0x7ff0000000000000ull) == 0x7ff0000000000000ull) {
+        const char* sign = (f64_bits & 0x8000000000000000ull) ? "-" : "";
+        uint64_t significand = f64_bits & 0xfffffffffffffull;
+        if (significand == 0) {
+          // Infinity.
+          Writef("%sINFINITY", sign);
+        } else {
+          // Nan.
+          Writef("f64_reinterpret_i64(0x%016" PRIx64 ") /* %snan:0x%013" PRIx64
+                 " */",
+                 f64_bits, sign, significand);
+        }
+      } else if (f64_bits == 0x8000000000000000ull) {
+        // Negative zero. Special-cased so it isn't written as -0 below.
+        Writef("-0.0");
+      } else {
+        Writef("%.17g", Bitcast<double>(f64_bits));
+      }
+      break;
+    }
+    case Type::V128: {
+      Writef("simde_wasm_i32x4_const(0x%08x, 0x%08x, 0x%08x, 0x%08x)",
+             const_.vec128().u32(0), const_.vec128().u32(1),
+             const_.vec128().u32(2), const_.vec128().u32(3));
+      break;
+    }
+
+    default:
+      WABT_UNREACHABLE;
+  }
+}
+
+void CWriter::WriteInitDecl() {
+  Write("void ", kAdminSymbolPrefix, module_prefix_, "_instantiate(",
+        ModuleInstanceTypeName(), "*");
+  for (const auto& import_module_name : import_module_set_) {
+    Write(", struct ", ModuleInstanceTypeName(import_module_name), "*");
+  }
+  Write(");", Newline());
+}
+
+void CWriter::WriteFreeDecl() {
+  Write("void ", kAdminSymbolPrefix, module_prefix_, "_free(",
+        ModuleInstanceTypeName(), "*);", Newline());
+}
+
+void CWriter::WriteGetFuncTypeDecl() {
+  Write("wasm_rt_func_type_t ", kAdminSymbolPrefix, module_prefix_,
+        "_get_func_type(uint32_t param_count, uint32_t result_count, ...);",
+        Newline());
+}
+
+void CWriter::WriteInitExpr(const ExprList& expr_list) {
+  if (expr_list.empty()) {
+    WABT_UNREACHABLE;
+  }
+
+  std::vector<std::string> mini_stack;
+
+  for (const auto& expr : expr_list) {
+    if (expr.type() == ExprType::Binary) {
+      // Extended const expressions include at least one binary op.
+      // This builds a C expression from the operands.
+      if (mini_stack.size() < 2) {
+        WABT_UNREACHABLE;
+      }
+
+      const auto binexpr = cast<BinaryExpr>(&expr);
+      char op;
+      switch (binexpr->opcode) {
+        case Opcode::I32Add:
+        case Opcode::I64Add:
+        case Opcode::F32Add:
+        case Opcode::F64Add:
+          op = '+';
+          break;
+
+        case Opcode::I32Sub:
+        case Opcode::I64Sub:
+        case Opcode::F32Sub:
+        case Opcode::F64Sub:
+          op = '-';
+          break;
+
+        case Opcode::I32Mul:
+        case Opcode::I64Mul:
+        case Opcode::F32Mul:
+        case Opcode::F64Mul:
+          op = '*';
+          break;
+
+        default:
+          WABT_UNREACHABLE;
+      }
+
+      std::string combination =
+          "((" + std::string(GetCTypeName(binexpr->opcode.GetParamType1())) +
+          ")" + mini_stack.at(mini_stack.size() - 2) + ")" + op + "((" +
+          std::string(GetCTypeName(binexpr->opcode.GetParamType2())) + ")" +
+          mini_stack.at(mini_stack.size() - 1) + ")";
+      mini_stack.resize(mini_stack.size() - 2);
+      mini_stack.push_back(std::move(combination));
+    } else {
+      // Leaf node (nullary const expression)
+      Stream* existing_stream = stream_;
+      MemoryStream terminal_stream;
+      stream_ = &terminal_stream;
+      WriteInitExprTerminal(&expr);
+      const auto& buf = terminal_stream.output_buffer();
+      mini_stack.emplace_back(reinterpret_cast<const char*>(buf.data.data()),
+                              buf.data.size());
+      stream_ = existing_stream;
+    }
+  }
+
+  if (mini_stack.size() != 1) {
+    WABT_UNREACHABLE;
+  }
+
+  Write(mini_stack.front());
+}
+
+void CWriter::WriteInitExprTerminal(const Expr* expr) {
+  switch (expr->type()) {
+    case ExprType::Const:
+      Write(cast<ConstExpr>(expr)->const_);
+      break;
+
+    case ExprType::GlobalGet:
+      Write(GlobalInstanceVar(cast<GlobalGetExpr>(expr)->var));
+      break;
+
+    case ExprType::RefFunc: {
+      const Func* func = module_->GetFunc(cast<RefFuncExpr>(expr)->var);
+      const FuncDeclaration& decl = func->decl;
+
+      assert(decl.has_func_type);
+      const FuncType* func_type = module_->GetFuncType(decl.type_var);
+
+      Write("(wasm_rt_funcref_t){", FuncTypeExpr(func_type), ", ",
+            "(wasm_rt_function_ptr_t)",
+            ExternalPtr(ModuleFieldType::Func, func->name), ", ");
+
+      bool is_import = import_module_sym_map_.count(func->name) != 0;
+      if (is_import) {
+        Write("instance->", GlobalName(ModuleFieldType::Import,
+                                       import_module_sym_map_[func->name]));
+      } else {
+        Write("instance");
+      }
+
+      Write("};", Newline());
+    } break;
+
+    case ExprType::RefNull:
+      Write(GetReferenceNullValue(cast<RefNullExpr>(expr)->type));
+      break;
+
+    default:
+      WABT_UNREACHABLE;
+  }
+}
+
+std::string CWriter::GenerateHeaderGuard() const {
+  std::string result;
+  for (char c : header_name_) {
+    if (isalnum(c) || c == '_') {
+      result += toupper(c);
+    } else {
+      result += '_';
+    }
+  }
+  result += "_GENERATED_";
+  return result;
+}
+
+void CWriter::WriteSourceTop() {
+  Write(s_source_includes);
+  Write(Newline(), "#include \"", header_name_, "\"", Newline());
+  Write(s_source_declarations, Newline());
+
+  if (module_->features_used.simd) {
+    if (!simd_used_in_header_) {
+      WriteV128Decl();
+    }
+    Write(s_simd_source_declarations);
+  }
+}
+
+void CWriter::WriteMultiCTop() {
+  if (c_streams_.size() > 1) {
+    assert(header_impl_name_.size() > 0);
+    Write("/* Automatically generated by wasm2c */", Newline());
+    Write("#include \"", header_impl_name_, "\"", Newline());
+  }
+}
+
+void CWriter::WriteMultiCTopEmpty() {
+  for (auto& stream : c_streams_) {
+    if (stream->offset() == 0) {
+      stream_ = stream;
+      Write("/* Empty wasm2c generated file */\n");
+      Write("typedef int dummy_def;");
+    }
+  }
+}
+
+void CWriter::WriteMultivalueTypes() {
+  for (TypeEntry* type : module_->types) {
+    FuncType* func_type = cast<FuncType>(type);
+    Index num_results = func_type->GetNumResults();
+    if (num_results <= 1) {
+      continue;
+    }
+    std::string name = MangleMultivalueTypes(func_type->sig.result_types);
+    // these ifndefs are actually to support importing multiple modules
+    // incidentally they also mean we don't have to bother with deduplication
+    Write("#ifndef ", name, Newline());
+    Write("#define ", name, " ", name, Newline());
+    Write("struct ", name, " ", OpenBrace());
+    for (Index i = 0; i < num_results; ++i) {
+      Type type = func_type->GetResultType(i);
+      Write(type);
+      Writef(" %c%d;", MangleType(type), i);
+      Write(Newline());
+    }
+    Write(CloseBrace(), ";", Newline(), "#endif  /* ", name, " */", Newline());
+  }
+}
+
+void CWriter::WriteTagTypes() {
+  for (const Tag* tag : module_->tags) {
+    const FuncDeclaration& tag_type = tag->decl;
+    Index num_params = tag_type.GetNumParams();
+    if (num_params <= 1) {
+      continue;
+    }
+    const std::string name = MangleTagTypes(tag_type.sig.param_types);
+    // use same method as WriteMultivalueTypes
+    Write("#ifndef ", name, Newline());
+    Write("#define ", name, " ", name, Newline());
+    Write("struct ", name, " ", OpenBrace());
+    for (Index i = 0; i < num_params; ++i) {
+      Type type = tag_type.GetParamType(i);
+      Write(type);
+      Writef(" %c%d;", MangleType(type), i);
+      Write(Newline());
+    }
+    Write(CloseBrace(), ";", Newline(), "#endif  /* ", name, " */", Newline());
+  }
+}
+
+void CWriter::WriteFuncTypeDecls() {
+  if (module_->types.empty()) {
+    return;
+  }
+
+  Write(Newline());
+
+  std::string serialized_type;
+  for (const TypeEntry* type : module_->types) {
+    const std::string name =
+        DefineGlobalScopeName(ModuleFieldType::Type, type->name);
+
+    if (c_streams_.size() > 1) {
+      Write("FUNC_TYPE_DECL_EXTERN_T(", name, ");", Newline());
+    }
+  }
+}
+
+void CWriter::WriteFuncTypes() {
+  if (module_->types.empty()) {
+    return;
+  }
+
+  Write(Newline());
+
+  std::unordered_map<std::string, std::string> type_hash;
+
+  std::string serialized_type;
+  for (const TypeEntry* type : module_->types) {
+    const std::string name = GetGlobalName(ModuleFieldType::Type, type->name);
+    SerializeFuncType(*cast<FuncType>(type), serialized_type);
+
+    auto prior_type = type_hash.find(serialized_type);
+    if (prior_type != type_hash.end()) {
+      /* duplicate function type */
+      unique_func_type_names_.push_back(prior_type->second);
+    } else {
+      unique_func_type_names_.push_back(name);
+      type_hash.emplace(serialized_type, name);
+      if (c_streams_.size() > 1) {
+        Write("FUNC_TYPE_EXTERN_T(");
+      } else {
+        Write("FUNC_TYPE_T(");
+      }
+      Write(name, ") = \"");
+      for (uint8_t x : serialized_type) {
+        Writef("\\x%02x", x);
+      }
+      Write("\";", Newline());
+    }
+  }
+}
+
+void CWriter::Write(const FuncTypeExpr& expr) {
+  Index func_type_index = module_->GetFuncTypeIndex(expr.func_type->sig);
+  Write(unique_func_type_names_.at(func_type_index));
+}
+
+// static
+void CWriter::SerializeFuncType(const FuncType& func_type,
+                                std::string& serialized_type) {
+  unsigned int len = func_type.GetNumParams() + func_type.GetNumResults() + 1;
+
+  char* const mangled_signature = static_cast<char*>(alloca(len));
+  char* next_byte = mangled_signature;
+
+  // step 1: serialize each param type
+  for (Index i = 0; i < func_type.GetNumParams(); ++i) {
+    *next_byte++ = MangleType(func_type.GetParamType(i));
+  }
+
+  // step 2: separate params and results with a space
+  *next_byte++ = ' ';
+
+  // step 3: serialize each result type
+  for (Index i = 0; i < func_type.GetNumResults(); ++i) {
+    *next_byte++ = MangleType(func_type.GetResultType(i));
+  }
+
+  assert(next_byte - mangled_signature == len);
+
+  // step 4: SHA-256 the whole string
+  sha256({mangled_signature, len}, serialized_type);
+}
+
+void CWriter::WriteTagDecls() {
+  Index tag_index = 0;
+  for (const Tag* tag : module_->tags) {
+    bool is_import = tag_index < module_->num_tag_imports;
+    if (!is_import) {
+      // Tags are identified and compared solely by their (unique) address.
+      // The data stored in this variable is never read.
+      if (tag_index == module_->num_tag_imports) {
+        Write(Newline());
+        Write("typedef char wasm_tag_placeholder_t;", Newline());
+      }
+      DefineGlobalScopeName(ModuleFieldType::Tag, tag->name);
+      if (c_streams_.size() > 1) {
+        Write("extern const wasm_tag_placeholder_t ",
+              GlobalName(ModuleFieldType::Tag, tag->name), ";", Newline());
+      }
+    }
+    tag_index++;
+  }
+}
+
+void CWriter::WriteTags() {
+  Write(Newline());
+  Index tag_index = 0;
+  for (const Tag* tag : module_->tags) {
+    bool is_import = tag_index < module_->num_tag_imports;
+    if (!is_import) {
+      Write(InternalSymbolScope(), "const wasm_tag_placeholder_t ",
+            GlobalName(ModuleFieldType::Tag, tag->name), ";", Newline());
+    }
+    tag_index++;
+  }
+}
+
+void CWriter::ComputeUniqueImports() {
+  using modname_name_pair = std::pair<std::string, std::string>;
+  std::map<modname_name_pair, const Import*> import_map;
+  for (const Import* import : module_->imports) {
+    // After emplacing, the returned bool says whether the insert happened;
+    // i.e., was there already an import with the same modname and name?
+    // If there was, make sure it was at least the same kind of import.
+    const auto iterator_and_insertion_bool = import_map.emplace(
+        modname_name_pair(import->module_name, import->field_name), import);
+    if (!iterator_and_insertion_bool.second) {
+      if (iterator_and_insertion_bool.first->second->kind() != import->kind()) {
+        UNIMPLEMENTED("contradictory import declaration");
+      } else {
+        fprintf(stderr, "warning: duplicate import declaration \"%s\" \"%s\"\n",
+                import->module_name.c_str(), import->field_name.c_str());
+      }
+    }
+    import_module_set_.insert(import->module_name);
+    if (import->kind() == ExternalKind::Func) {
+      import_func_module_set_.insert(import->module_name);
+    }
+  }
+
+  for (const auto& node : import_map) {
+    unique_imports_.push_back(node.second);
+  }
+}
+
+void CWriter::BeginInstance() {
+  if (module_->imports.empty()) {
+    Write("typedef struct ", ModuleInstanceTypeName(), " ", OpenBrace());
+    return;
+  }
+
+  ComputeUniqueImports();
+
+  // define names of per-instance imports
+  for (const Import* import : module_->imports) {
+    DefineImportName(import, import->module_name, import->field_name);
+  }
+
+  // Forward declaring module instance types
+  for (const auto& import_module : import_module_set_) {
+    DefineImportedModuleInstanceName(import_module);
+    Write("struct ", ModuleInstanceTypeName(import_module), ";", Newline());
+  }
+
+  // Forward declaring module imports
+  for (const Import* import : unique_imports_) {
+    if ((import->kind() == ExternalKind::Func) ||
+        (import->kind() == ExternalKind::Tag)) {
+      continue;
+    }
+
+    Write("extern ");
+    switch (import->kind()) {
+      case ExternalKind::Global: {
+        const Global& global = cast<GlobalImport>(import)->global;
+        Write(global.type);
+        break;
+      }
+
+      case ExternalKind::Memory: {
+        Write("wasm_rt_memory_t");
+        break;
+      }
+
+      case ExternalKind::Table:
+        WriteTableType(cast<TableImport>(import)->table.elem_type);
+        break;
+
+      default:
+        WABT_UNREACHABLE;
+    }
+    Write("* ", ExportName(import->module_name, import->field_name), "(struct ",
+          ModuleInstanceTypeName(import->module_name), "*);", Newline());
+  }
+  Write(Newline());
+
+  // Add pointers to module instances that any func is imported from,
+  // so that imported functions can be given their own module instances
+  // when invoked
+  Write("typedef struct ", ModuleInstanceTypeName(), " ", OpenBrace());
+  for (const auto& import_module : import_func_module_set_) {
+    Write("struct ", ModuleInstanceTypeName(import_module), "* ",
+          GlobalName(ModuleFieldType::Import, import_module), ";", Newline());
+  }
+
+  for (const Import* import : unique_imports_) {
+    if ((import->kind() == ExternalKind::Func) ||
+        (import->kind() == ExternalKind::Tag)) {
+      continue;
+    }
+
+    Write("/* import: '", SanitizeForComment(import->module_name), "' '",
+          SanitizeForComment(import->field_name), "' */", Newline());
+
+    switch (import->kind()) {
+      case ExternalKind::Global:
+        WriteGlobal(cast<GlobalImport>(import)->global,
+                    std::string("*") +
+                        ExportName(import->module_name, import->field_name));
+        break;
+
+      case ExternalKind::Memory:
+        WriteMemory(std::string("*") +
+                    ExportName(import->module_name, import->field_name));
+        break;
+
+      case ExternalKind::Table: {
+        const Table& table = cast<TableImport>(import)->table;
+        WriteTable(std::string("*") +
+                       ExportName(import->module_name, import->field_name),
+                   table.elem_type);
+      } break;
+
+      default:
+        WABT_UNREACHABLE;
+    }
+
+    Write(Newline());
+  }
+}
+
+// Write module-wide imports (funcs & tags), which aren't tied to an instance.
+void CWriter::WriteImports() {
+  if (unique_imports_.empty())
+    return;
+
+  Write(Newline());
+
+  for (const Import* import : unique_imports_) {
+    if (import->kind() == ExternalKind::Func) {
+      Write(Newline(), "/* import: '", SanitizeForComment(import->module_name),
+            "' '", SanitizeForComment(import->field_name), "' */", Newline());
+      const Func& func = cast<FuncImport>(import)->func;
+      WriteImportFuncDeclaration(
+          func.decl, import->module_name,
+          ExportName(import->module_name, import->field_name));
+      Write(";");
+      Write(Newline());
+    } else if (import->kind() == ExternalKind::Tag) {
+      Write(Newline(), "/* import: '", SanitizeForComment(import->module_name),
+            "' '", SanitizeForComment(import->field_name), "' */", Newline());
+      Write("extern const wasm_rt_tag_t ",
+            ExportName(import->module_name, import->field_name), ";",
+            Newline());
+    }
+  }
+}
+
+void CWriter::WriteFuncDeclarations() {
+  if (module_->funcs.size() == module_->num_func_imports)
+    return;
+
+  Write(Newline());
+
+  Index func_index = 0;
+  for (const Func* func : module_->funcs) {
+    bool is_import = func_index < module_->num_func_imports;
+    if (!is_import) {
+      Write(InternalSymbolScope());
+      WriteFuncDeclaration(
+          func->decl, DefineGlobalScopeName(ModuleFieldType::Func, func->name));
+      Write(";", Newline());
+    }
+    ++func_index;
+  }
+}
+
+void CWriter::WriteFuncDeclaration(const FuncDeclaration& decl,
+                                   const std::string& name) {
+  Write(ResultType(decl.sig.result_types), " ", name, "(");
+  Write(ModuleInstanceTypeName(), "*");
+  WriteParamTypes(decl);
+  Write(")");
+}
+
+void CWriter::WriteImportFuncDeclaration(const FuncDeclaration& decl,
+                                         const std::string& module_name,
+                                         const std::string& name) {
+  Write(ResultType(decl.sig.result_types), " ", name, "(");
+  Write("struct ", ModuleInstanceTypeName(module_name), "*");
+  WriteParamTypes(decl);
+  Write(")");
+}
+
+void CWriter::WriteCallIndirectFuncDeclaration(const FuncDeclaration& decl,
+                                               const std::string& name) {
+  Write(ResultType(decl.sig.result_types), " ", name, "(void*");
+  WriteParamTypes(decl);
+  Write(")");
+}
+
+static bool func_uses_simd(const FuncSignature& sig) {
+  return std::any_of(sig.param_types.begin(), sig.param_types.end(),
+                     [](auto x) { return x == Type::V128; }) ||
+         std::any_of(sig.result_types.begin(), sig.result_types.end(),
+                     [](auto x) { return x == Type::V128; });
+}
+
+void CWriter::ComputeSimdScope() {
+  simd_used_in_header_ =
+      module_->features_used.simd &&
+      (std::any_of(module_->globals.begin(), module_->globals.end(),
+                   [](const auto& x) { return x->type == Type::V128; }) ||
+       std::any_of(module_->imports.begin(), module_->imports.end(),
+                   [](const auto& x) {
+                     return x->kind() == ExternalKind::Func &&
+                            func_uses_simd(cast<FuncImport>(x)->func.decl.sig);
+                   }) ||
+       std::any_of(module_->exports.begin(), module_->exports.end(),
+                   [&](const auto& x) {
+                     return x->kind == ExternalKind::Func &&
+                            func_uses_simd(module_->GetFunc(x->var)->decl.sig);
+                   }));
+}
+
+void CWriter::WriteHeaderIncludes() {
+  Write("#include \"wasm-rt.h\"", Newline());
+
+  if (module_->features_used.exceptions) {
+    Write("#include \"wasm-rt-exceptions.h\"", Newline(), Newline());
+  }
+
+  if (simd_used_in_header_) {
+    WriteV128Decl();
+  }
+
+  Write(Newline());
+}
+
+void CWriter::WriteV128Decl() {
+  Write("#include <simde/wasm/simd128.h>", Newline(), Newline());
+  Write("#ifndef WASM_RT_SIMD_TYPE_DEFINED", Newline(),
+        "#define WASM_RT_SIMD_TYPE_DEFINED", Newline(),
+        "typedef simde_v128_t v128;", Newline(), "#endif", Newline(),
+        Newline());
+}
+
+void CWriter::WriteModuleInstance() {
+  BeginInstance();
+  WriteGlobals();
+  WriteMemories();
+  WriteTables();
+  WriteDataInstances();
+  WriteElemInstances();
+
+  // C forbids an empty struct
+  if (module_->globals.empty() && module_->memories.empty() &&
+      module_->tables.empty() && import_func_module_set_.empty()) {
+    Write("char dummy_member;", Newline());
+  }
+
+  Write(CloseBrace(), " ", ModuleInstanceTypeName(), ";", Newline());
+  Write(Newline());
+}
+
+void CWriter::WriteGlobals() {
+  Index global_index = 0;
+  if (module_->globals.size() != module_->num_global_imports) {
+    for (const Global* global : module_->globals) {
+      bool is_import = global_index < module_->num_global_imports;
+      if (!is_import) {
+        WriteGlobal(*global, DefineInstanceMemberName(ModuleFieldType::Global,
+                                                      global->name));
+        Write(Newline());
+      }
+      ++global_index;
+    }
+  }
+}
+
+void CWriter::WriteGlobal(const Global& global, const std::string& name) {
+  Write(global.type, " ", name, ";");
+}
+
+void CWriter::WriteGlobalPtr(const Global& global, const std::string& name) {
+  Write(global.type, "* ", name, "(", ModuleInstanceTypeName(), "* instance)");
+}
+
+void CWriter::WriteMemories() {
+  if (module_->memories.size() == module_->num_memory_imports)
+    return;
+
+  Index memory_index = 0;
+  for (const Memory* memory : module_->memories) {
+    bool is_import = memory_index < module_->num_memory_imports;
+    if (!is_import) {
+      WriteMemory(
+          DefineInstanceMemberName(ModuleFieldType::Memory, memory->name));
+      Write(Newline());
+    }
+    ++memory_index;
+  }
+}
+
+void CWriter::WriteMemory(const std::string& name) {
+  Write("wasm_rt_memory_t ", name, ";");
+}
+
+void CWriter::WriteMemoryPtr(const std::string& name) {
+  Write("wasm_rt_memory_t* ", name, "(", ModuleInstanceTypeName(),
+        "* instance)");
+}
+
+void CWriter::WriteTables() {
+  if (module_->tables.size() == module_->num_table_imports) {
+    return;
+  }
+
+  Index table_index = 0;
+  for (const Table* table : module_->tables) {
+    bool is_import = table_index < module_->num_table_imports;
+    if (!is_import) {
+      WriteTable(DefineInstanceMemberName(ModuleFieldType::Table, table->name),
+                 table->elem_type);
+      Write(Newline());
+    }
+    ++table_index;
+  }
+}
+
+void CWriter::WriteTable(const std::string& name, const wabt::Type& type) {
+  WriteTableType(type);
+  Write(" ", name, ";");
+}
+
+void CWriter::WriteTablePtr(const std::string& name, const Table& table) {
+  WriteTableType(table.elem_type);
+  Write("* ", name, "(", ModuleInstanceTypeName(), "* instance)");
+}
+
+void CWriter::WriteTableType(const wabt::Type& type) {
+  Write("wasm_rt_", GetReferenceTypeName(type), "_table_t");
+}
+
+void CWriter::WriteGlobalInitializers() {
+  if (module_->globals.empty())
+    return;
+
+  Write(Newline(), "static void init_globals(", ModuleInstanceTypeName(),
+        "* instance) ", OpenBrace());
+  Index global_index = 0;
+  for (const Global* global : module_->globals) {
+    bool is_import = global_index < module_->num_global_imports;
+    if (!is_import) {
+      assert(!global->init_expr.empty());
+      Write(ExternalInstanceRef(ModuleFieldType::Global, global->name), " = ");
+      WriteInitExpr(global->init_expr);
+      Write(";", Newline());
+    }
+    ++global_index;
+  }
+  Write(CloseBrace(), Newline());
+}
+
+static inline bool is_droppable(const DataSegment* data_segment) {
+  return (data_segment->kind == SegmentKind::Passive) &&
+         (!data_segment->data.empty());
+}
+
+static inline bool is_droppable(const ElemSegment* elem_segment) {
+  return (elem_segment->kind == SegmentKind::Passive) &&
+         (!elem_segment->elem_exprs.empty());
+}
+
+void CWriter::WriteDataInstances() {
+  for (const DataSegment* data_segment : module_->data_segments) {
+    std::string name =
+        DefineGlobalScopeName(ModuleFieldType::DataSegment, data_segment->name);
+    if (is_droppable(data_segment)) {
+      Write("bool ", "data_segment_dropped_", name, " : 1;", Newline());
+    }
+  }
+}
+
+void CWriter::WriteDataInitializerDecls() {
+  if (module_->memories.empty()) {
+    return;
+  }
+
+  for (const DataSegment* data_segment : module_->data_segments) {
+    if (data_segment->data.empty()) {
+      continue;
+    }
+
+    if (c_streams_.size() > 1) {
+      Write(Newline(), "extern const u8 data_segment_data_",
+            GlobalName(ModuleFieldType::DataSegment, data_segment->name), "[];",
+            Newline());
+    }
+  }
+}
+
+void CWriter::WriteDataInitializers() {
+  if (module_->memories.empty()) {
+    return;
+  }
+
+  for (const DataSegment* data_segment : module_->data_segments) {
+    if (data_segment->data.empty()) {
+      continue;
+    }
+
+    Write(Newline(), InternalSymbolScope(), "const u8 data_segment_data_",
+          GlobalName(ModuleFieldType::DataSegment, data_segment->name),
+          "[] = ", OpenBrace());
+    size_t i = 0;
+    for (uint8_t x : data_segment->data) {
+      Writef("0x%02x, ", x);
+      if ((++i % 12) == 0)
+        Write(Newline());
+    }
+    if (i > 0)
+      Write(Newline());
+    Write(CloseBrace(), ";", Newline());
+  }
+
+  Write(Newline(), "static void init_memories(", ModuleInstanceTypeName(),
+        "* instance) ", OpenBrace());
+  if (module_->memories.size() > module_->num_memory_imports) {
+    Index memory_idx = module_->num_memory_imports;
+    for (Index i = memory_idx; i < module_->memories.size(); i++) {
+      const Memory* memory = module_->memories[i];
+      uint64_t max;
+      if (memory->page_limits.has_max) {
+        max = memory->page_limits.max;
+      } else {
+        max = memory->page_limits.is_64 ? (static_cast<uint64_t>(1) << 48)
+                                        : 65536;
+      }
+      Write("wasm_rt_allocate_memory(",
+            ExternalInstancePtr(ModuleFieldType::Memory, memory->name), ", ",
+            memory->page_limits.initial, ", ", max, ", ",
+            memory->page_limits.is_64, ");", Newline());
+    }
+  }
+
+  for (const DataSegment* data_segment : module_->data_segments) {
+    if (data_segment->kind != SegmentKind::Active) {
+      continue;
+    }
+    const Memory* memory =
+        module_->memories[module_->GetMemoryIndex(data_segment->memory_var)];
+    Write("LOAD_DATA(",
+          ExternalInstanceRef(ModuleFieldType::Memory, memory->name), ", ");
+    WriteInitExpr(data_segment->offset);
+    if (data_segment->data.empty()) {
+      Write(", NULL, 0");
+    } else {
+      Write(", data_segment_data_",
+            GlobalName(ModuleFieldType::DataSegment, data_segment->name), ", ",
+            data_segment->data.size());
+    }
+    Write(");", Newline());
+  }
+
+  Write(CloseBrace(), Newline());
+
+  if (!module_->data_segments.empty()) {
+    Write(Newline(), "static void init_data_instances(",
+          ModuleInstanceTypeName(), " *instance) ", OpenBrace());
+
+    for (const DataSegment* data_segment : module_->data_segments) {
+      if (is_droppable(data_segment)) {
+        Write("instance->data_segment_dropped_",
+              GlobalName(ModuleFieldType::DataSegment, data_segment->name),
+              " = false;", Newline());
+      }
+    }
+
+    Write(CloseBrace(), Newline());
+  }
+}
+
+void CWriter::WriteElemInstances() {
+  for (const ElemSegment* elem_segment : module_->elem_segments) {
+    std::string name =
+        DefineGlobalScopeName(ModuleFieldType::ElemSegment, elem_segment->name);
+    if (is_droppable(elem_segment)) {
+      Write("bool ", "elem_segment_dropped_", name, " : 1;", Newline());
+    }
+  }
+}
+
+void CWriter::WriteElemInitializerDecls() {
+  if (module_->tables.empty()) {
+    return;
+  }
+
+  for (const ElemSegment* elem_segment : module_->elem_segments) {
+    if (elem_segment->elem_exprs.empty()) {
+      continue;
+    }
+
+    if (elem_segment->elem_type == Type::ExternRef) {
+      // no need to store externref elem initializers because only
+      // ref.null is possible
+      continue;
+    }
+
+    if (c_streams_.size() > 1) {
+      Write(Newline(),
+            "extern const wasm_elem_segment_expr_t elem_segment_exprs_",
+            GlobalName(ModuleFieldType::ElemSegment, elem_segment->name), "[];",
+            Newline());
+    }
+  }
+}
+
+void CWriter::WriteElemInitializers() {
+  if (module_->tables.empty()) {
+    return;
+  }
+
+  for (const ElemSegment* elem_segment : module_->elem_segments) {
+    if (elem_segment->elem_exprs.empty()) {
+      continue;
+    }
+
+    if (elem_segment->elem_type == Type::ExternRef) {
+      // no need to store externref elem initializers because only
+      // ref.null is possible
+      continue;
+    }
+
+    Write(Newline(), InternalSymbolScope(),
+          "const wasm_elem_segment_expr_t elem_segment_exprs_",
+          GlobalName(ModuleFieldType::ElemSegment, elem_segment->name),
+          "[] = ", OpenBrace());
+
+    for (const ExprList& elem_expr : elem_segment->elem_exprs) {
+      assert(elem_expr.size() == 1);
+      const Expr& expr = elem_expr.front();
+      switch (expr.type()) {
+        case ExprType::RefFunc: {
+          const Func* func = module_->GetFunc(cast<RefFuncExpr>(&expr)->var);
+          const FuncType* func_type = module_->GetFuncType(func->decl.type_var);
+          Write("{", FuncTypeExpr(func_type), ", (wasm_rt_function_ptr_t)",
+                ExternalPtr(ModuleFieldType::Func, func->name), ", ");
+          const bool is_import = import_module_sym_map_.count(func->name) != 0;
+          if (is_import) {
+            Write("offsetof(", ModuleInstanceTypeName(), ", ",
+                  GlobalName(ModuleFieldType::Import,
+                             import_module_sym_map_[func->name]),
+                  ")");
+          } else {
+            Write("0");
+          }
+          Write("},", Newline());
+        } break;
+        case ExprType::RefNull:
+          Write("{NULL, NULL, 0},", Newline());
+          break;
+        default:
+          WABT_UNREACHABLE;
+      }
+    }
+    Write(CloseBrace(), ";", Newline());
+  }
+
+  Write(Newline(), "static void init_tables(", ModuleInstanceTypeName(),
+        "* instance) ", OpenBrace());
+
+  if (module_->tables.size() > module_->num_table_imports) {
+    Index table_idx = module_->num_table_imports;
+    for (Index i = table_idx; i < module_->tables.size(); i++) {
+      const Table* table = module_->tables[i];
+      uint32_t max =
+          table->elem_limits.has_max ? table->elem_limits.max : UINT32_MAX;
+      Write("wasm_rt_allocate_", GetReferenceTypeName(table->elem_type),
+            "_table(", ExternalInstancePtr(ModuleFieldType::Table, table->name),
+            ", ", table->elem_limits.initial, ", ", max, ");", Newline());
+    }
+  }
+
+  for (const ElemSegment* elem_segment : module_->elem_segments) {
+    if (elem_segment->kind != SegmentKind::Active) {
+      continue;
+    }
+
+    const Table* table = module_->GetTable(elem_segment->table_var);
+
+    WriteElemTableInit(true, elem_segment, table);
+  }
+
+  Write(CloseBrace(), Newline());
+
+  if (!module_->elem_segments.empty()) {
+    Write(Newline(), "static void init_elem_instances(",
+          ModuleInstanceTypeName(), " *instance) ", OpenBrace());
+
+    for (const ElemSegment* elem_segment : module_->elem_segments) {
+      if (is_droppable(elem_segment)) {
+        Write("instance->elem_segment_dropped_",
+              GlobalName(ModuleFieldType::ElemSegment, elem_segment->name),
+              " = false;", Newline());
+      }
+    }
+
+    Write(CloseBrace(), Newline());
+  }
+}
+
+void CWriter::WriteElemTableInit(bool active_initialization,
+                                 const ElemSegment* src_segment,
+                                 const Table* dst_table) {
+  assert(dst_table->elem_type == Type::FuncRef ||
+         dst_table->elem_type == Type::ExternRef);
+  assert(dst_table->elem_type == src_segment->elem_type);
+
+  Write(GetReferenceTypeName(dst_table->elem_type), "_table_init(",
+        ExternalInstancePtr(ModuleFieldType::Table, dst_table->name), ", ");
+
+  // elem segment exprs needed only for funcref tables
+  // because externref tables can only be initialized with ref.null
+  if (dst_table->elem_type == Type::FuncRef) {
+    if (src_segment->elem_exprs.empty()) {
+      Write("NULL, ");
+    } else {
+      Write("elem_segment_exprs_",
+            GlobalName(ModuleFieldType::ElemSegment, src_segment->name), ", ");
+    }
+  }
+
+  // src_size, dest_addr, src_addr, N
+  if (active_initialization) {
+    Write(src_segment->elem_exprs.size(), ", ");
+    WriteInitExpr(src_segment->offset);
+    Write(", 0, ", src_segment->elem_exprs.size());
+  } else {
+    if (is_droppable(src_segment)) {
+      Write("(instance->elem_segment_dropped_",
+            GlobalName(ModuleFieldType::ElemSegment, src_segment->name),
+            " ? 0 : ", src_segment->elem_exprs.size(), "), ");
+    } else {
+      Write("0, ");
+    }
+    Write(StackVar(2), ", ", StackVar(1), ", ", StackVar(0));
+  }
+
+  if (dst_table->elem_type == Type::FuncRef) {
+    Write(", instance");
+  }
+
+  Write(");", Newline());
+}
+
+void CWriter::WriteExports(CWriterPhase kind) {
+  if (module_->exports.empty())
+    return;
+
+  for (const Export* export_ : module_->exports) {
+    Write(Newline(), "/* export: '", SanitizeForComment(export_->name), "' */",
+          Newline());
+
+    const std::string mangled_name = ExportName(export_->name);
+    std::string internal_name;
+    std::vector<std::string> index_to_name;
+
+    switch (export_->kind) {
+      case ExternalKind::Func: {
+        const Func* func = module_->GetFunc(export_->var);
+        internal_name = func->name;
+        if (kind == CWriterPhase::Declarations) {
+          WriteFuncDeclaration(func->decl, mangled_name);
+        } else {
+          func_ = func;
+          local_syms_ = global_syms_;
+          local_sym_map_.clear();
+          stack_var_sym_map_.clear();
+          Write(ResultType(func_->decl.sig.result_types), " ", mangled_name,
+                "(");
+          MakeTypeBindingReverseMapping(func_->GetNumParamsAndLocals(),
+                                        func_->bindings, &index_to_name);
+          WriteParams(index_to_name);
+        }
+        break;
+      }
+
+      case ExternalKind::Global: {
+        const Global* global = module_->GetGlobal(export_->var);
+        internal_name = global->name;
+        WriteGlobalPtr(*global, mangled_name);
+        break;
+      }
+
+      case ExternalKind::Memory: {
+        const Memory* memory = module_->GetMemory(export_->var);
+        internal_name = memory->name;
+        WriteMemoryPtr(mangled_name);
+        break;
+      }
+
+      case ExternalKind::Table: {
+        const Table* table = module_->GetTable(export_->var);
+        internal_name = table->name;
+        WriteTablePtr(mangled_name, *table);
+        break;
+      }
+
+      case ExternalKind::Tag: {
+        const Tag* tag = module_->GetTag(export_->var);
+        internal_name = tag->name;
+        if (kind == CWriterPhase::Declarations) {
+          Write("extern ");
+        }
+        Write("const wasm_rt_tag_t ", mangled_name);
+        break;
+      }
+
+      default:
+        WABT_UNREACHABLE;
+    }
+
+    if (kind == CWriterPhase::Declarations) {
+      Write(";", Newline());
+      continue;
+    }
+
+    Write(" ");
+    switch (export_->kind) {
+      case ExternalKind::Func: {
+        Write(OpenBrace());
+        Write("return ", ExternalRef(ModuleFieldType::Func, internal_name),
+              "(");
+
+        bool is_import = import_module_sym_map_.count(internal_name) != 0;
+        if (is_import) {
+          Write("instance->",
+                GlobalName(ModuleFieldType::Import,
+                           import_module_sym_map_[internal_name]));
+        } else {
+          Write("instance");
+        }
+        WriteParamSymbols(index_to_name);
+        Write(CloseBrace(), Newline());
+
+        local_sym_map_.clear();
+        stack_var_sym_map_.clear();
+        func_ = nullptr;
+        break;
+      }
+
+      case ExternalKind::Global:
+        Write(OpenBrace());
+        Write("return ",
+              ExternalInstancePtr(ModuleFieldType::Global, internal_name), ";",
+              Newline());
+        Write(CloseBrace(), Newline());
+        break;
+
+      case ExternalKind::Memory:
+        Write(OpenBrace());
+        Write("return ",
+              ExternalInstancePtr(ModuleFieldType::Memory, internal_name), ";",
+              Newline());
+        Write(CloseBrace(), Newline());
+        break;
+
+      case ExternalKind::Table:
+        Write(OpenBrace());
+        Write("return ",
+              ExternalInstancePtr(ModuleFieldType::Table, internal_name), ";",
+              Newline());
+        Write(CloseBrace(), Newline());
+        break;
+
+      case ExternalKind::Tag:
+        Write("= ", ExternalPtr(ModuleFieldType::Tag, internal_name), ";",
+              Newline());
+        break;
+
+      default:
+        WABT_UNREACHABLE;
+    }
+  }
+}
+
+void CWriter::WriteInit() {
+  Write(Newline(), "void ", kAdminSymbolPrefix, module_prefix_, "_instantiate(",
+        ModuleInstanceTypeName(), "* instance");
+  for (const auto& import_module_name : import_module_set_) {
+    Write(", struct ", ModuleInstanceTypeName(import_module_name), "* ",
+          GlobalName(ModuleFieldType::Import, import_module_name));
+  }
+  Write(") ", OpenBrace());
+
+  Write("assert(wasm_rt_is_initialized());", Newline());
+
+  if (!import_module_set_.empty()) {
+    Write("init_instance_import(instance");
+    for (const auto& import_module_name : import_module_set_) {
+      Write(", ", GlobalName(ModuleFieldType::Import, import_module_name));
+    }
+    Write(");", Newline());
+  }
+
+  if (!module_->globals.empty()) {
+    Write("init_globals(instance);", Newline());
+  }
+  if (!module_->tables.empty()) {
+    Write("init_tables(instance);", Newline());
+  }
+  if (!module_->memories.empty()) {
+    Write("init_memories(instance);", Newline());
+  }
+  if (!module_->tables.empty() && !module_->elem_segments.empty()) {
+    Write("init_elem_instances(instance);", Newline());
+  }
+  if (!module_->memories.empty() && !module_->data_segments.empty()) {
+    Write("init_data_instances(instance);", Newline());
+  }
+
+  for (Var* var : module_->starts) {
+    Write(ExternalRef(ModuleFieldType::Func, module_->GetFunc(*var)->name));
+    bool is_import =
+        import_module_sym_map_.count(module_->GetFunc(*var)->name) != 0;
+    if (is_import) {
+      Write("(instance->",
+            GlobalName(ModuleFieldType::Import,
+                       import_module_sym_map_[module_->GetFunc(*var)->name]),
+            ");");
+    } else {
+      Write("(instance);");
+    }
+    Write(Newline());
+  }
+  Write(CloseBrace(), Newline());
+}
+
+void CWriter::WriteGetFuncType() {
+  Write(Newline(), "wasm_rt_func_type_t ", kAdminSymbolPrefix, module_prefix_,
+        "_get_func_type(uint32_t param_count, uint32_t result_count, "
+        "...) ",
+        OpenBrace());
+
+  Write("va_list args;", Newline());
+
+  for (const TypeEntry* type : module_->types) {
+    const FuncType* func_type = cast<FuncType>(type);
+    const FuncSignature& signature = func_type->sig;
+
+    Write(Newline(), "if (param_count == ", signature.GetNumParams(),
+          " && result_count == ", signature.GetNumResults(), ") ", OpenBrace());
+    Write("va_start(args, result_count);", Newline());
+    Write("if (true");
+    for (const auto& t : signature.param_types) {
+      Write(" && va_arg(args, wasm_rt_type_t) == ", TypeEnum(t));
+    }
+    for (const auto& t : signature.result_types) {
+      Write(" && va_arg(args, wasm_rt_type_t) == ", TypeEnum(t));
+    }
+    Write(") ", OpenBrace());
+    Write("va_end(args);", Newline());
+    Write("return ", FuncTypeExpr(func_type), ";", Newline());
+    Write(CloseBrace(), Newline());
+    Write("va_end(args);", Newline());
+    Write(CloseBrace(), Newline());
+  }
+
+  Write(Newline(), "return NULL;", Newline());
+  Write(CloseBrace(), Newline());
+}
+
+void CWriter::WriteInitInstanceImport() {
+  if (import_module_set_.empty())
+    return;
+
+  Write(Newline(), "static void init_instance_import(",
+        ModuleInstanceTypeName(), "* instance");
+  for (const auto& import_module_name : import_module_set_) {
+    Write(", struct ", ModuleInstanceTypeName(import_module_name), "* ",
+          GlobalName(ModuleFieldType::Import, import_module_name));
+  }
+  Write(")", OpenBrace());
+
+  for (const auto& import_module : import_func_module_set_) {
+    Write("instance->", GlobalName(ModuleFieldType::Import, import_module),
+          " = ", GlobalName(ModuleFieldType::Import, import_module), ";",
+          Newline());
+  }
+
+  for (const Import* import : unique_imports_) {
+    switch (import->kind()) {
+      case ExternalKind::Func:
+      case ExternalKind::Tag:
+        break;
+
+      case ExternalKind::Global:
+      case ExternalKind::Memory:
+      case ExternalKind::Table: {
+        Write("instance->", ExportName(import->module_name, import->field_name),
+              " = ", ExportName(import->module_name, import->field_name), "(",
+              GlobalName(ModuleFieldType::Import, import->module_name), ");",
+              Newline());
+        break;
+      }
+
+      default:
+        WABT_UNREACHABLE;
+    }
+  }
+  Write(CloseBrace(), Newline());
+}
+
+void CWriter::WriteImportProperties(CWriterPhase kind) {
+  if (import_module_set_.empty())
+    return;
+
+  Write(Newline());
+
+  auto write_import_prop = [&](const Import* import, std::string prop,
+                               std::string type, uint64_t value) {
+    if (kind == CWriterPhase::Declarations) {
+      Write("extern ");
+    }
+    Write("const ", type, " ", kAdminSymbolPrefix, module_prefix_, "_", prop,
+          "_", MangleModuleName(import->module_name), "_",
+          MangleName(import->field_name));
+    if (kind == CWriterPhase::Definitions) {
+      Write(" = ", value);
+    }
+
+    Write(";", Newline());
+  };
+
+  for (const Import* import : unique_imports_) {
+    if (import->kind() == ExternalKind::Memory) {
+      const Limits* limits = &(cast<MemoryImport>(import)->memory.page_limits);
+      // We use u64 so we can handle both 32-bit and 64-bit memories
+      const uint64_t default_max = limits->is_64
+                                       ? (static_cast<uint64_t>(1) << 48)
+                                       : (static_cast<uint64_t>(1) << 16);
+      write_import_prop(import, "min", "u64", limits->initial);
+      write_import_prop(import, "max", "u64",
+                        limits->has_max ? limits->max : default_max);
+      write_import_prop(import, "is64", "u8", limits->is_64);
+    } else if (import->kind() == ExternalKind::Table) {
+      const Limits* limits = &(cast<TableImport>(import)->table.elem_limits);
+      const uint64_t default_max = std::numeric_limits<uint32_t>::max();
+      write_import_prop(import, "min", "u32", limits->initial);
+      write_import_prop(import, "max", "u32",
+                        limits->has_max ? limits->max : default_max);
+    } else {
+      continue;
+    }
+  }
+}
+
+void CWriter::WriteFree() {
+  Write(Newline(), "void ", kAdminSymbolPrefix, module_prefix_, "_free(",
+        ModuleInstanceTypeName(), "* instance) ", OpenBrace());
+
+  {
+    Index table_index = 0;
+    for (const Table* table : module_->tables) {
+      bool is_import = table_index < module_->num_table_imports;
+      if (!is_import) {
+        Write("wasm_rt_free_", GetReferenceTypeName(table->elem_type),
+              "_table(",
+              ExternalInstancePtr(ModuleFieldType::Table, table->name), ");",
+              Newline());
+      }
+      ++table_index;
+    }
+  }
+
+  {
+    Index memory_index = 0;
+    for (const Memory* memory : module_->memories) {
+      bool is_import = memory_index < module_->num_memory_imports;
+      if (!is_import) {
+        Write("wasm_rt_free_memory(",
+              ExternalInstancePtr(ModuleFieldType::Memory, memory->name), ");",
+              Newline());
+      }
+      ++memory_index;
+    }
+  }
+
+  Write(CloseBrace(), Newline());
+}
+
+void CWriter::WriteFuncs() {
+  std::vector<size_t> c_stream_assignment =
+      name_to_output_file_index_(module_->funcs.begin(), module_->funcs.end(),
+                                 module_->num_func_imports, c_streams_.size());
+  Index func_index = 0;
+  for (const Func* func : module_->funcs) {
+    bool is_import = func_index < module_->num_func_imports;
+    if (!is_import) {
+      stream_ = c_streams_.at(c_stream_assignment.at(func_index));
+      Write(*func);
+    }
+    ++func_index;
+  }
+}
+
+void CWriter::PushFuncSection(std::string_view include_condition) {
+  func_sections_.emplace_back(include_condition, MemoryStream{});
+  stream_ = &func_sections_.back().second;
+}
+
+void CWriter::Write(const Func& func) {
+  func_ = &func;
+  local_syms_.clear();
+  local_sym_map_.clear();
+  stack_var_sym_map_.clear();
+  func_sections_.clear();
+  func_includes_.clear();
+
+  Stream* prev_stream = stream_;
+
+  /*
+   * If offset of stream_ is 0, this is the first time some function is written
+   * to this stream, then write multi c top.
+   */
+  if (stream_->offset() == 0) {
+    WriteMultiCTop();
+  }
+  Write(Newline());
+
+  PushFuncSection();
+  Write(ResultType(func.decl.sig.result_types), " ",
+        GlobalName(ModuleFieldType::Func, func.name), "(");
+  WriteParamsAndLocals();
+  Write("FUNC_PROLOGUE;", Newline());
+
+  PushFuncSection();
+
+  std::string label = DefineLabelName(kImplicitFuncLabel);
+  ResetTypeStack(0);
+  std::string empty;  // Must not be temporary, since address is taken by Label.
+  PushLabel(LabelType::Func, empty, func.decl.sig);
+  Write(func.exprs, LabelDecl(label));
+  PopLabel();
+  ResetTypeStack(0);
+  PushTypes(func.decl.sig.result_types);
+  Write("FUNC_EPILOGUE;", Newline());
+
+  // Return the top of the stack implicitly.
+  Index num_results = func.GetNumResults();
+  if (num_results == 1) {
+    Write("return ", StackVar(0), ";", Newline());
+  } else if (num_results >= 2) {
+    Write(OpenBrace());
+    Write(ResultType(func.decl.sig.result_types), " tmp;", Newline());
+    for (Index i = 0; i < num_results; ++i) {
+      Type type = func.GetResultType(i);
+      Writef("tmp.%c%d = ", MangleType(type), i);
+      Write(StackVar(num_results - i - 1), ";", Newline());
+    }
+    Write("return tmp;", Newline());
+    Write(CloseBrace(), Newline());
+  }
+
+  stream_ = prev_stream;
+
+  for (size_t i = 0; i < func_sections_.size(); ++i) {
+    auto& [condition, stream] = func_sections_.at(i);
+    std::unique_ptr<OutputBuffer> buf = stream.ReleaseOutputBuffer();
+    if (condition.empty() || func_includes_.count(condition)) {
+      stream_->WriteData(buf->data.data(), buf->data.size());
+    }
+
+    if (i == 0) {
+      WriteStackVarDeclarations();  // these come immediately after section #0
+                                    // (return type/name/params/locals)
+    }
+  }
+
+  Write(CloseBrace(), Newline());
+
+  func_ = nullptr;
+}
+
+void CWriter::WriteParamsAndLocals() {
+  std::vector<std::string> index_to_name;
+  MakeTypeBindingReverseMapping(func_->GetNumParamsAndLocals(), func_->bindings,
+                                &index_to_name);
+  WriteParams(index_to_name);
+  Write(" ", OpenBrace());
+  WriteLocals(index_to_name);
+}
+
+void CWriter::WriteParams(const std::vector<std::string>& index_to_name) {
+  Write(ModuleInstanceTypeName(), "* instance");
+  if (func_->GetNumParams() != 0) {
+    Indent(4);
+    for (Index i = 0; i < func_->GetNumParams(); ++i) {
+      Write(", ");
+      if (i != 0 && (i % 8) == 0) {
+        Write(Newline());
+      }
+      Write(func_->GetParamType(i), " ", DefineParamName(index_to_name[i]));
+    }
+    Dedent(4);
+  }
+  Write(")");
+}
+
+void CWriter::WriteParamSymbols(const std::vector<std::string>& index_to_name) {
+  if (func_->GetNumParams() != 0) {
+    Indent(4);
+    for (Index i = 0; i < func_->GetNumParams(); ++i) {
+      Write(", ");
+      if (i != 0 && (i % 8) == 0) {
+        Write(Newline());
+      }
+      Write(ParamName(index_to_name[i]));
+    }
+    Dedent(4);
+  }
+  Write(");", Newline());
+}
+
+void CWriter::WriteParamTypes(const FuncDeclaration& decl) {
+  if (decl.GetNumParams() != 0) {
+    for (Index i = 0; i < decl.GetNumParams(); ++i) {
+      Write(", ");
+      Write(decl.GetParamType(i));
+    }
+  }
+}
+
+void CWriter::WriteLocals(const std::vector<std::string>& index_to_name) {
+  Index num_params = func_->GetNumParams();
+  for (Type type : {Type::I32, Type::I64, Type::F32, Type::F64, Type::V128,
+                    Type::FuncRef, Type::ExternRef}) {
+    Index local_index = 0;
+    size_t count = 0;
+    for (Type local_type : func_->local_types) {
+      if (local_type == type) {
+        if (count == 0) {
+          Write(type, " ");
+          Indent(4);
+        } else {
+          Write(", ");
+          if ((count % 8) == 0)
+            Write(Newline());
+        }
+
+        Write(DefineParamName(index_to_name[num_params + local_index]), " = ");
+        if (local_type == Type::FuncRef || local_type == Type::ExternRef) {
+          Write(GetReferenceNullValue(local_type));
+        } else if (local_type == Type::V128) {
+          Write("simde_wasm_i64x2_make(0, 0)");
+        } else {
+          Write("0");
+        }
+        ++count;
+      }
+      ++local_index;
+    }
+    if (count != 0) {
+      Dedent(4);
+      Write(";", Newline());
+    }
+  }
+}
+
+void CWriter::WriteStackVarDeclarations() {
+  for (Type type : {Type::I32, Type::I64, Type::F32, Type::F64, Type::V128,
+                    Type::FuncRef, Type::ExternRef}) {
+    size_t count = 0;
+    for (const auto& [pair, name] : stack_var_sym_map_) {
+      Type stp_type = pair.second;
+
+      if (stp_type == type) {
+        if (count == 0) {
+          Write(type, " ");
+          Indent(4);
+        } else {
+          Write(", ");
+          if ((count % 8) == 0)
+            Write(Newline());
+        }
+
+        Write(name);
+        ++count;
+      }
+    }
+    if (count != 0) {
+      Dedent(4);
+      Write(";", Newline());
+    }
+  }
+}
+
+void CWriter::Write(const Block& block) {
+  std::string label = DefineLabelName(block.label);
+  DropTypes(block.decl.GetNumParams());
+  size_t mark = MarkTypeStack();
+  PushLabel(LabelType::Block, block.label, block.decl.sig);
+  PushTypes(block.decl.sig.param_types);
+  Write(block.exprs, LabelDecl(label));
+  ResetTypeStack(mark);
+  PopLabel();
+  PushTypes(block.decl.sig.result_types);
+}
+
+size_t CWriter::BeginTry(const TryExpr& tryexpr) {
+  Write(OpenBrace()); /* beginning of try-catch */
+  const std::string tlabel = DefineLabelName(tryexpr.block.label);
+  Write("WASM_RT_UNWIND_TARGET *", tlabel,
+        "_outer_target = wasm_rt_get_unwind_target();", Newline());
+  Write("WASM_RT_UNWIND_TARGET ", tlabel, "_unwind_target;", Newline());
+  Write("if (!wasm_rt_try(", tlabel, "_unwind_target)) ");
+  Write(OpenBrace()); /* beginning of try block */
+  DropTypes(tryexpr.block.decl.GetNumParams());
+  const size_t mark = MarkTypeStack();
+  PushLabel(LabelType::Try, tryexpr.block.label, tryexpr.block.decl.sig);
+  PushTypes(tryexpr.block.decl.sig.param_types);
+  Write("wasm_rt_set_unwind_target(&", tlabel, "_unwind_target);", Newline());
+  PushTryCatch(tlabel);
+  Write(tryexpr.block.exprs);
+  ResetTypeStack(mark);
+  Write("wasm_rt_set_unwind_target(", tlabel, "_outer_target);", Newline());
+  Write(CloseBrace());          /* end of try block */
+  Write(" else ", OpenBrace()); /* beginning of catch blocks or delegate */
+  assert(label_stack_.back().name == tryexpr.block.label);
+  assert(label_stack_.back().label_type == LabelType::Try);
+  label_stack_.back().label_type = LabelType::Catch;
+  if (try_catch_stack_.back().used) {
+    Write(tlabel, "_catch:;", Newline());
+  }
+
+  return mark;
+}
+
+void CWriter::WriteTryCatch(const TryExpr& tryexpr) {
+  const size_t mark = BeginTry(tryexpr);
+
+  /* exception has been thrown -- do we catch it? */
+
+  const LabelName tlabel = LabelName(tryexpr.block.label);
+
+  Write("wasm_rt_set_unwind_target(", tlabel, "_outer_target);", Newline());
+  PopTryCatch();
+
+  /* save the thrown exception to the stack if it might be rethrown later */
+  PushFuncSection(tryexpr.block.label);
+  Write("/* save exception ", tlabel, " for rethrow */", Newline());
+  Write("const wasm_rt_tag_t ", tlabel, "_tag = wasm_rt_exception_tag();",
+        Newline());
+  Write("uint32_t ", tlabel, "_size = wasm_rt_exception_size();", Newline());
+  Write("void *", tlabel, " = alloca(", tlabel, "_size);", Newline());
+  Write("wasm_rt_memcpy(", tlabel, ", wasm_rt_exception(), ", tlabel, "_size);",
+        Newline());
+  PushFuncSection();
+
+  assert(!tryexpr.catches.empty());
+  bool has_catch_all{};
+  for (auto it = tryexpr.catches.cbegin(); it != tryexpr.catches.cend(); ++it) {
+    if (it == tryexpr.catches.cbegin()) {
+      Write(Newline());
+    } else {
+      Write(" else ");
+    }
+    ResetTypeStack(mark);
+    Write(*it);
+    if (it->IsCatchAll()) {
+      has_catch_all = true;
+      break;
+    }
+  }
+  if (!has_catch_all) {
+    /* if not caught, rethrow */
+    Write(" else ", OpenBrace());
+    WriteThrow();
+    Write(CloseBrace(), Newline());
+  }
+  Write(CloseBrace(), Newline()); /* end of catch blocks */
+  Write(CloseBrace(), Newline()); /* end of try-catch */
+
+  ResetTypeStack(mark);
+  assert(!label_stack_.empty());
+  assert(label_stack_.back().name == tryexpr.block.label);
+  Write(LabelDecl(GetLocalName(tryexpr.block.label, true)));
+  PopLabel();
+  PushTypes(tryexpr.block.decl.sig.result_types);
+}
+
+void CWriter::Write(const Catch& c) {
+  if (c.IsCatchAll()) {
+    Write(c.exprs);
+    return;
+  }
+
+  Write("if (wasm_rt_exception_tag() == ",
+        ExternalPtr(ModuleFieldType::Tag, module_->GetTag(c.var)->name), ") ",
+        OpenBrace());
+
+  const Tag* tag = module_->GetTag(c.var);
+  const FuncDeclaration& tag_type = tag->decl;
+  const Index num_params = tag_type.GetNumParams();
+  if (num_params == 1) {
+    PushType(tag_type.GetParamType(0));
+    Write("wasm_rt_memcpy(&", StackVar(0), ", wasm_rt_exception(), sizeof(",
+          tag_type.GetParamType(0), "));", Newline());
+  } else if (num_params > 1) {
+    for (const auto& type : tag_type.sig.param_types) {
+      PushType(type);
+    }
+    Write(OpenBrace());
+    Write("struct ", MangleTagTypes(tag_type.sig.param_types), " tmp;",
+          Newline());
+    Write("wasm_rt_memcpy(&tmp, wasm_rt_exception(), sizeof(tmp));", Newline());
+    for (unsigned int i = 0; i < tag_type.sig.param_types.size(); ++i) {
+      Write(StackVar(i));
+      Writef(" = tmp.%c%d;", MangleType(tag_type.sig.param_types.at(i)), i);
+      Write(Newline());
+    }
+
+    Write(CloseBrace(), Newline());
+  }
+
+  Write(c.exprs);
+  Write(CloseBrace());
+}
+
+void CWriter::WriteThrow() {
+  if (try_catch_stack_.empty()) {
+    Write("wasm_rt_throw();", Newline());
+  } else {
+    Write("goto ", try_catch_stack_.back().name, "_catch;", Newline());
+    try_catch_stack_.back().used = true;
+  }
+}
+
+void CWriter::PushTryCatch(const std::string& name) {
+  try_catch_stack_.emplace_back(name, try_catch_stack_.size());
+}
+
+void CWriter::PopTryCatch() {
+  assert(!try_catch_stack_.empty());
+  try_catch_stack_.pop_back();
+}
+
+void CWriter::WriteTryDelegate(const TryExpr& tryexpr) {
+  const size_t mark = BeginTry(tryexpr);
+
+  /* exception has been thrown -- where do we delegate it? */
+
+  if (tryexpr.delegate_target.is_index()) {
+    /* must be the implicit function label */
+    assert(!try_catch_stack_.empty());
+    const std::string& unwind_name = try_catch_stack_.at(0).name;
+    Write("wasm_rt_set_unwind_target(", unwind_name, "_outer_target);",
+          Newline());
+
+    Write("wasm_rt_throw();", Newline());
+  } else {
+    const Label* label = FindLabel(tryexpr.delegate_target, false);
+
+    assert(try_catch_stack_.size() >= label->try_catch_stack_size);
+
+    if (label->label_type == LabelType::Try) {
+      Write("goto ", LabelName(label->name), "_catch;", Newline());
+      try_catch_stack_.at(label->try_catch_stack_size).used = true;
+    } else if (label->try_catch_stack_size == 0) {
+      assert(!try_catch_stack_.empty());
+      const std::string& unwind_name = try_catch_stack_.at(0).name;
+      Write("wasm_rt_set_unwind_target(", unwind_name, "_outer_target);",
+            Newline());
+
+      Write("wasm_rt_throw();", Newline());
+    } else {
+      const std::string label_target =
+          try_catch_stack_.at(label->try_catch_stack_size - 1).name + "_catch";
+      Write("goto ", label_target, ";", Newline());
+      try_catch_stack_.at(label->try_catch_stack_size - 1).used = true;
+    }
+  }
+
+  Write(CloseBrace(), Newline());
+  Write(CloseBrace(), Newline());
+
+  PopTryCatch();
+  ResetTypeStack(mark);
+  assert(!label_stack_.empty());
+  assert(label_stack_.back().name == tryexpr.block.label);
+  Write(LabelDecl(GetLocalName(tryexpr.block.label, true)));
+  PopLabel();
+  PushTypes(tryexpr.block.decl.sig.result_types);
+}
+
+void CWriter::Write(const ExprList& exprs) {
+  for (const Expr& expr : exprs) {
+    switch (expr.type()) {
+      case ExprType::Binary:
+        Write(*cast<BinaryExpr>(&expr));
+        break;
+
+      case ExprType::Block:
+        Write(cast<BlockExpr>(&expr)->block);
+        break;
+
+      case ExprType::Br:
+        Write(GotoLabel(cast<BrExpr>(&expr)->var), Newline());
+        // Stop processing this ExprList, since the following are unreachable.
+        return;
+
+      case ExprType::BrIf:
+        Write("if (", StackVar(0), ") {");
+        DropTypes(1);
+        Write(GotoLabel(cast<BrIfExpr>(&expr)->var), "}", Newline());
+        break;
+
+      case ExprType::BrTable: {
+        const auto* bt_expr = cast<BrTableExpr>(&expr);
+        Write("switch (", StackVar(0), ") ", OpenBrace());
+        DropTypes(1);
+        Index i = 0;
+        for (const Var& var : bt_expr->targets) {
+          Write("case ", i++, ": ", GotoLabel(var), Newline());
+        }
+        Write("default: ");
+        Write(GotoLabel(bt_expr->default_target), Newline(), CloseBrace(),
+              Newline());
+        // Stop processing this ExprList, since the following are unreachable.
+        return;
+      }
+
+      case ExprType::Call: {
+        const Var& var = cast<CallExpr>(&expr)->var;
+        const Func& func = *module_->GetFunc(var);
+        Index num_params = func.GetNumParams();
+        Index num_results = func.GetNumResults();
+        assert(type_stack_.size() >= num_params);
+        if (num_results > 1) {
+          Write(OpenBrace());
+          Write("struct ", MangleMultivalueTypes(func.decl.sig.result_types));
+          Write(" tmp = ");
+        } else if (num_results == 1) {
+          Write(StackVar(num_params - 1, func.GetResultType(0)), " = ");
+        }
+
+        assert(var.is_name());
+        Write(ExternalRef(ModuleFieldType::Func, var.name()), "(");
+        bool is_import = import_module_sym_map_.count(func.name) != 0;
+        if (is_import) {
+          Write("instance->", GlobalName(ModuleFieldType::Import,
+                                         import_module_sym_map_[func.name]));
+        } else {
+          Write("instance");
+        }
+        for (Index i = 0; i < num_params; ++i) {
+          Write(", ");
+          Write(StackVar(num_params - i - 1));
+        }
+        Write(");", Newline());
+        DropTypes(num_params);
+        if (num_results > 1) {
+          for (Index i = 0; i < num_results; ++i) {
+            Type type = func.GetResultType(i);
+            PushType(type);
+            Write(StackVar(0));
+            Writef(" = tmp.%c%d;", MangleType(type), i);
+            Write(Newline());
+          }
+          Write(CloseBrace(), Newline());
+        } else {
+          PushTypes(func.decl.sig.result_types);
+        }
+        break;
+      }
+
+      case ExprType::CallIndirect: {
+        const FuncDeclaration& decl = cast<CallIndirectExpr>(&expr)->decl;
+        Index num_params = decl.GetNumParams();
+        Index num_results = decl.GetNumResults();
+        assert(type_stack_.size() > num_params);
+        if (num_results > 1) {
+          Write(OpenBrace());
+          Write("struct ", MangleMultivalueTypes(decl.sig.result_types));
+          Write(" tmp = ");
+        } else if (num_results == 1) {
+          Write(StackVar(num_params, decl.GetResultType(0)), " = ");
+        }
+
+        const Table* table =
+            module_->GetTable(cast<CallIndirectExpr>(&expr)->table);
+
+        assert(decl.has_func_type);
+        const FuncType* func_type = module_->GetFuncType(decl.type_var);
+
+        Write("CALL_INDIRECT(",
+              ExternalInstanceRef(ModuleFieldType::Table, table->name), ", ");
+        WriteCallIndirectFuncDeclaration(decl, "(*)");
+        Write(", ", FuncTypeExpr(func_type), ", ", StackVar(0));
+        Write(", ", ExternalInstanceRef(ModuleFieldType::Table, table->name),
+              ".data[", StackVar(0), "].module_instance");
+        for (Index i = 0; i < num_params; ++i) {
+          Write(", ", StackVar(num_params - i));
+        }
+        Write(");", Newline());
+        DropTypes(num_params + 1);
+        if (num_results > 1) {
+          for (Index i = 0; i < num_results; ++i) {
+            Type type = decl.GetResultType(i);
+            PushType(type);
+            Write(StackVar(0));
+            Writef(" = tmp.%c%d;", MangleType(type), i);
+            Write(Newline());
+          }
+          Write(CloseBrace(), Newline());
+        } else {
+          PushTypes(decl.sig.result_types);
+        }
+        break;
+      }
+
+      case ExprType::CodeMetadata:
+        break;
+
+      case ExprType::Compare:
+        Write(*cast<CompareExpr>(&expr));
+        break;
+
+      case ExprType::Const: {
+        const Const& const_ = cast<ConstExpr>(&expr)->const_;
+        PushType(const_.type());
+        Write(StackVar(0), " = ", const_, ";", Newline());
+        break;
+      }
+
+      case ExprType::Convert:
+        Write(*cast<ConvertExpr>(&expr));
+        break;
+
+      case ExprType::Drop:
+        DropTypes(1);
+        break;
+
+      case ExprType::GlobalGet: {
+        const Var& var = cast<GlobalGetExpr>(&expr)->var;
+        PushType(module_->GetGlobal(var)->type);
+        Write(StackVar(0), " = ", GlobalInstanceVar(var), ";", Newline());
+        break;
+      }
+
+      case ExprType::GlobalSet: {
+        const Var& var = cast<GlobalSetExpr>(&expr)->var;
+        Write(GlobalInstanceVar(var), " = ", StackVar(0), ";", Newline());
+        DropTypes(1);
+        break;
+      }
+
+      case ExprType::If: {
+        const IfExpr& if_ = *cast<IfExpr>(&expr);
+        Write("if (", StackVar(0), ") ", OpenBrace());
+        DropTypes(1);
+        std::string label = DefineLabelName(if_.true_.label);
+        DropTypes(if_.true_.decl.GetNumParams());
+        size_t mark = MarkTypeStack();
+        PushLabel(LabelType::If, if_.true_.label, if_.true_.decl.sig);
+        PushTypes(if_.true_.decl.sig.param_types);
+        Write(if_.true_.exprs, CloseBrace());
+        if (!if_.false_.empty()) {
+          ResetTypeStack(mark);
+          PushTypes(if_.true_.decl.sig.param_types);
+          Write(" else ", OpenBrace(), if_.false_, CloseBrace());
+        }
+        ResetTypeStack(mark);
+        Write(Newline(), LabelDecl(label));
+        PopLabel();
+        PushTypes(if_.true_.decl.sig.result_types);
+        break;
+      }
+
+      case ExprType::Load:
+        Write(*cast<LoadExpr>(&expr));
+        break;
+
+      case ExprType::LocalGet: {
+        const Var& var = cast<LocalGetExpr>(&expr)->var;
+        PushType(func_->GetLocalType(var));
+        Write(StackVar(0), " = ", var, ";", Newline());
+        break;
+      }
+
+      case ExprType::LocalSet: {
+        const Var& var = cast<LocalSetExpr>(&expr)->var;
+        Write(var, " = ", StackVar(0), ";", Newline());
+        DropTypes(1);
+        break;
+      }
+
+      case ExprType::LocalTee: {
+        const Var& var = cast<LocalTeeExpr>(&expr)->var;
+        Write(var, " = ", StackVar(0), ";", Newline());
+        break;
+      }
+
+      case ExprType::Loop: {
+        const Block& block = cast<LoopExpr>(&expr)->block;
+        if (!block.exprs.empty()) {
+          Write(DefineLabelName(block.label), ": ");
+          Indent();
+          DropTypes(block.decl.GetNumParams());
+          size_t mark = MarkTypeStack();
+          PushLabel(LabelType::Loop, block.label, block.decl.sig);
+          PushTypes(block.decl.sig.param_types);
+          Write(Newline(), block.exprs);
+          ResetTypeStack(mark);
+          PopLabel();
+          PushTypes(block.decl.sig.result_types);
+          Dedent();
+        }
+        break;
+      }
+
+      case ExprType::MemoryFill: {
+        const auto inst = cast<MemoryFillExpr>(&expr);
+        Memory* memory =
+            module_->memories[module_->GetMemoryIndex(inst->memidx)];
+        Write("memory_fill(",
+              ExternalInstancePtr(ModuleFieldType::Memory, memory->name), ", ",
+              StackVar(2), ", ", StackVar(1), ", ", StackVar(0), ");",
+              Newline());
+        DropTypes(3);
+      } break;
+
+      case ExprType::MemoryCopy: {
+        const auto inst = cast<MemoryCopyExpr>(&expr);
+        Memory* dest_memory =
+            module_->memories[module_->GetMemoryIndex(inst->destmemidx)];
+        const Memory* src_memory = module_->GetMemory(inst->srcmemidx);
+        Write("memory_copy(",
+              ExternalInstancePtr(ModuleFieldType::Memory, dest_memory->name),
+              ", ",
+              ExternalInstancePtr(ModuleFieldType::Memory, src_memory->name),
+              ", ", StackVar(2), ", ", StackVar(1), ", ", StackVar(0), ");",
+              Newline());
+        DropTypes(3);
+      } break;
+
+      case ExprType::MemoryInit: {
+        const auto inst = cast<MemoryInitExpr>(&expr);
+        Memory* dest_memory =
+            module_->memories[module_->GetMemoryIndex(inst->memidx)];
+        const DataSegment* src_data = module_->GetDataSegment(inst->var);
+        Write("memory_init(",
+              ExternalInstancePtr(ModuleFieldType::Memory, dest_memory->name),
+              ", ");
+        if (src_data->data.empty()) {
+          Write("NULL, 0");
+        } else {
+          Write("data_segment_data_",
+                GlobalName(ModuleFieldType::DataSegment, src_data->name), ", ");
+          if (is_droppable(src_data)) {
+            Write("(", "instance->data_segment_dropped_",
+                  GlobalName(ModuleFieldType::DataSegment, src_data->name),
+                  " ? 0 : ", src_data->data.size(), ")");
+          } else {
+            Write("0");
+          }
+        }
+
+        Write(", ", StackVar(2), ", ", StackVar(1), ", ", StackVar(0), ");",
+              Newline());
+        DropTypes(3);
+      } break;
+
+      case ExprType::TableInit: {
+        const auto inst = cast<TableInitExpr>(&expr);
+        Table* dest_table =
+            module_->tables[module_->GetTableIndex(inst->table_index)];
+        const ElemSegment* src_segment =
+            module_->GetElemSegment(inst->segment_index);
+
+        WriteElemTableInit(false, src_segment, dest_table);
+        DropTypes(3);
+      } break;
+
+      case ExprType::DataDrop: {
+        const auto inst = cast<DataDropExpr>(&expr);
+        const DataSegment* data = module_->GetDataSegment(inst->var);
+        if (is_droppable(data)) {
+          Write("instance->data_segment_dropped_",
+                GlobalName(ModuleFieldType::DataSegment, data->name),
+                " = true;", Newline());
+        }
+      } break;
+
+      case ExprType::ElemDrop: {
+        const auto inst = cast<ElemDropExpr>(&expr);
+        const ElemSegment* seg = module_->GetElemSegment(inst->var);
+        if (is_droppable(seg)) {
+          Write("instance->elem_segment_dropped_",
+                GlobalName(ModuleFieldType::ElemSegment, seg->name), " = true;",
+                Newline());
+        }
+      } break;
+
+      case ExprType::TableCopy: {
+        const auto inst = cast<TableCopyExpr>(&expr);
+        Table* dest_table =
+            module_->tables[module_->GetTableIndex(inst->dst_table)];
+        const Table* src_table = module_->GetTable(inst->src_table);
+        if (dest_table->elem_type != src_table->elem_type) {
+          WABT_UNREACHABLE;
+        }
+
+        Write(
+            GetReferenceTypeName(dest_table->elem_type), "_table_copy(",
+            ExternalInstancePtr(ModuleFieldType::Table, dest_table->name), ", ",
+            ExternalInstancePtr(ModuleFieldType::Table, src_table->name), ", ",
+            StackVar(2), ", ", StackVar(1), ", ", StackVar(0), ");", Newline());
+        DropTypes(3);
+      } break;
+
+      case ExprType::TableGet: {
+        const Table* table = module_->GetTable(cast<TableGetExpr>(&expr)->var);
+        Write(StackVar(0, table->elem_type), " = ",
+              GetReferenceTypeName(table->elem_type), "_table_get(",
+              ExternalInstancePtr(ModuleFieldType::Table, table->name), ", ",
+              StackVar(0), ");", Newline());
+        DropTypes(1);
+        PushType(table->elem_type);
+      } break;
+
+      case ExprType::TableSet: {
+        const Table* table = module_->GetTable(cast<TableSetExpr>(&expr)->var);
+        Write(GetReferenceTypeName(table->elem_type), "_table_set(",
+              ExternalInstancePtr(ModuleFieldType::Table, table->name), ", ",
+              StackVar(1), ", ", StackVar(0), ");", Newline());
+        DropTypes(2);
+      } break;
+
+      case ExprType::TableGrow: {
+        const Table* table = module_->GetTable(cast<TableGrowExpr>(&expr)->var);
+        Write(StackVar(1, Type::I32), " = wasm_rt_grow_",
+              GetReferenceTypeName(table->elem_type), "_table(",
+              ExternalInstancePtr(ModuleFieldType::Table, table->name), ", ",
+              StackVar(0), ", ", StackVar(1), ");", Newline());
+        DropTypes(2);
+        PushType(Type::I32);
+      } break;
+
+      case ExprType::TableSize: {
+        const Table* table = module_->GetTable(cast<TableSizeExpr>(&expr)->var);
+
+        PushType(Type::I32);
+        Write(StackVar(0), " = ",
+              ExternalInstanceRef(ModuleFieldType::Table, table->name),
+              ".size;", Newline());
+      } break;
+
+      case ExprType::TableFill: {
+        const Table* table = module_->GetTable(cast<TableFillExpr>(&expr)->var);
+        Write(GetReferenceTypeName(table->elem_type), "_table_fill(",
+              ExternalInstancePtr(ModuleFieldType::Table, table->name), ", ",
+              StackVar(2), ", ", StackVar(1), ", ", StackVar(0), ");",
+              Newline());
+        DropTypes(3);
+      } break;
+
+      case ExprType::RefFunc: {
+        const Func* func = module_->GetFunc(cast<RefFuncExpr>(&expr)->var);
+        PushType(Type::FuncRef);
+        const FuncDeclaration& decl = func->decl;
+
+        assert(decl.has_func_type);
+        const FuncType* func_type = module_->GetFuncType(decl.type_var);
+
+        Write(StackVar(0), " = (wasm_rt_funcref_t){", FuncTypeExpr(func_type),
+              ", (wasm_rt_function_ptr_t)",
+              ExternalPtr(ModuleFieldType::Func, func->name), ", ");
+
+        bool is_import = import_module_sym_map_.count(func->name) != 0;
+        if (is_import) {
+          Write("instance->", GlobalName(ModuleFieldType::Import,
+                                         import_module_sym_map_[func->name]));
+        } else {
+          Write("instance");
+        }
+
+        Write("};", Newline());
+      } break;
+
+      case ExprType::RefNull:
+        PushType(cast<RefNullExpr>(&expr)->type);
+        Write(StackVar(0), " = ",
+              GetReferenceNullValue(cast<RefNullExpr>(&expr)->type), ";",
+              Newline());
+        break;
+
+      case ExprType::RefIsNull:
+        switch (StackType(0)) {
+          case Type::FuncRef:
+            Write(StackVar(0, Type::I32), " = (", StackVar(0), ".func == NULL",
+                  ");", Newline());
+            break;
+          case Type::ExternRef:
+            Write(StackVar(0, Type::I32), " = (", StackVar(0),
+                  " == ", GetReferenceNullValue(Type::ExternRef), ");",
+                  Newline());
+            break;
+          default:
+            WABT_UNREACHABLE;
+        }
+
+        DropTypes(1);
+        PushType(Type::I32);
+        break;
+
+      case ExprType::MemoryGrow: {
+        Memory* memory = module_->memories[module_->GetMemoryIndex(
+            cast<MemoryGrowExpr>(&expr)->memidx)];
+
+        Write(StackVar(0), " = wasm_rt_grow_memory(",
+              ExternalInstancePtr(ModuleFieldType::Memory, memory->name), ", ",
+              StackVar(0), ");", Newline());
+        break;
+      }
+
+      case ExprType::MemorySize: {
+        Memory* memory = module_->memories[module_->GetMemoryIndex(
+            cast<MemorySizeExpr>(&expr)->memidx)];
+
+        PushType(memory->page_limits.IndexType());
+        Write(StackVar(0), " = ",
+              ExternalInstanceRef(ModuleFieldType::Memory, memory->name),
+              ".pages;", Newline());
+        break;
+      }
+
+      case ExprType::Nop:
+        break;
+
+      case ExprType::Return:
+        // Goto the function label instead; this way we can do shared function
+        // cleanup code in one place.
+        Write(GotoLabel(Var(label_stack_.size() - 1, {})), Newline());
+        // Stop processing this ExprList, since the following are unreachable.
+        return;
+
+      case ExprType::Select: {
+        Type type = StackType(1);
+        Write(StackVar(2), " = ", StackVar(0), " ? ", StackVar(2), " : ",
+              StackVar(1), ";", Newline());
+        DropTypes(3);
+        PushType(type);
+        break;
+      }
+
+      case ExprType::Store:
+        Write(*cast<StoreExpr>(&expr));
+        break;
+
+      case ExprType::Unary:
+        Write(*cast<UnaryExpr>(&expr));
+        break;
+
+      case ExprType::Ternary:
+        Write(*cast<TernaryExpr>(&expr));
+        break;
+
+      case ExprType::SimdLaneOp: {
+        Write(*cast<SimdLaneOpExpr>(&expr));
+        break;
+      }
+
+      case ExprType::SimdLoadLane: {
+        Write(*cast<SimdLoadLaneExpr>(&expr));
+        break;
+      }
+
+      case ExprType::SimdStoreLane: {
+        Write(*cast<SimdStoreLaneExpr>(&expr));
+        break;
+      }
+
+      case ExprType::SimdShuffleOp: {
+        Write(*cast<SimdShuffleOpExpr>(&expr));
+        break;
+      }
+
+      case ExprType::LoadSplat:
+        Write(*cast<LoadSplatExpr>(&expr));
+        break;
+
+      case ExprType::LoadZero:
+        Write(*cast<LoadZeroExpr>(&expr));
+        break;
+
+      case ExprType::Unreachable:
+        Write("UNREACHABLE;", Newline());
+        return;
+
+      case ExprType::Throw: {
+        const Var& var = cast<ThrowExpr>(&expr)->var;
+        const Tag* tag = module_->GetTag(var);
+
+        Index num_params = tag->decl.GetNumParams();
+        if (num_params == 0) {
+          Write("wasm_rt_load_exception(",
+                ExternalPtr(ModuleFieldType::Tag, tag->name), ", 0, NULL);",
+                Newline());
+        } else if (num_params == 1) {
+          Write("wasm_rt_load_exception(",
+                ExternalPtr(ModuleFieldType::Tag, tag->name), ", sizeof(",
+                tag->decl.GetParamType(0), "), &", StackVar(0), ");",
+                Newline());
+        } else {
+          Write(OpenBrace());
+          Write("struct ", MangleTagTypes(tag->decl.sig.param_types));
+          Write(" tmp = {");
+          for (Index i = 0; i < num_params; ++i) {
+            Write(StackVar(i), ", ");
+          }
+          Write("};", Newline());
+          Write("wasm_rt_load_exception(",
+                ExternalPtr(ModuleFieldType::Tag, tag->name),
+                ", sizeof(tmp), &tmp);", Newline());
+          Write(CloseBrace(), Newline());
+        }
+
+        WriteThrow();
+      } break;
+
+      case ExprType::Rethrow: {
+        const RethrowExpr* rethrow = cast<RethrowExpr>(&expr);
+        assert(rethrow->var.is_name());
+        const LabelName ex{rethrow->var.name()};
+        func_includes_.insert(rethrow->var.name());
+        Write("wasm_rt_load_exception(", ex, "_tag, ", ex, "_size, ", ex, ");",
+              Newline());
+        WriteThrow();
+      } break;
+
+      case ExprType::Try: {
+        const TryExpr& tryexpr = *cast<TryExpr>(&expr);
+        switch (tryexpr.kind) {
+          case TryKind::Plain:
+            Write(tryexpr.block);
+            break;
+          case TryKind::Catch:
+            WriteTryCatch(tryexpr);
+            break;
+          case TryKind::Delegate:
+            WriteTryDelegate(tryexpr);
+            break;
+        }
+      } break;
+
+      case ExprType::AtomicLoad:
+      case ExprType::AtomicRmw:
+      case ExprType::AtomicRmwCmpxchg:
+      case ExprType::AtomicStore:
+      case ExprType::AtomicWait:
+      case ExprType::AtomicFence:
+      case ExprType::AtomicNotify:
+      case ExprType::ReturnCall:
+      case ExprType::ReturnCallIndirect:
+      case ExprType::CallRef:
+        UNIMPLEMENTED("...");
+        break;
+    }
+  }
+}
+
+void CWriter::WriteSimpleUnaryExpr(Opcode opcode, const char* op) {
+  Type result_type = opcode.GetResultType();
+  Write(StackVar(0, result_type), " = ", op, "(", StackVar(0), ");", Newline());
+  DropTypes(1);
+  PushType(opcode.GetResultType());
+}
+
+void CWriter::WriteInfixBinaryExpr(Opcode opcode,
+                                   const char* op,
+                                   AssignOp assign_op) {
+  Type result_type = opcode.GetResultType();
+  Write(StackVar(1, result_type));
+  if (assign_op == AssignOp::Allowed) {
+    Write(" ", op, "= ", StackVar(0));
+  } else {
+    Write(" = ", StackVar(1), " ", op, " ", StackVar(0));
+  }
+  Write(";", Newline());
+  DropTypes(2);
+  PushType(result_type);
+}
+
+void CWriter::WritePrefixBinaryExpr(Opcode opcode, const char* op) {
+  Type result_type = opcode.GetResultType();
+  Write(StackVar(1, result_type), " = ", op, "(", StackVar(1), ", ",
+        StackVar(0), ");", Newline());
+  DropTypes(2);
+  PushType(result_type);
+}
+
+void CWriter::WriteSignedBinaryExpr(Opcode opcode, const char* op) {
+  Type result_type = opcode.GetResultType();
+  Type type = opcode.GetParamType1();
+  assert(opcode.GetParamType2() == type);
+  Write(StackVar(1, result_type), " = (", type, ")((", SignedType(type), ")",
+        StackVar(1), " ", op, " (", SignedType(type), ")", StackVar(0), ");",
+        Newline());
+  DropTypes(2);
+  PushType(result_type);
+}
+
+void CWriter::Write(const BinaryExpr& expr) {
+  switch (expr.opcode) {
+    case Opcode::I32Add:
+    case Opcode::I64Add:
+    case Opcode::F32Add:
+    case Opcode::F64Add:
+      WriteInfixBinaryExpr(expr.opcode, "+");
+      break;
+
+    case Opcode::I32Sub:
+    case Opcode::I64Sub:
+    case Opcode::F32Sub:
+    case Opcode::F64Sub:
+      WriteInfixBinaryExpr(expr.opcode, "-");
+      break;
+
+    case Opcode::I32Mul:
+    case Opcode::I64Mul:
+    case Opcode::F32Mul:
+    case Opcode::F64Mul:
+      WriteInfixBinaryExpr(expr.opcode, "*");
+      break;
+
+    case Opcode::I32DivS:
+      WritePrefixBinaryExpr(expr.opcode, "I32_DIV_S");
+      break;
+
+    case Opcode::I64DivS:
+      WritePrefixBinaryExpr(expr.opcode, "I64_DIV_S");
+      break;
+
+    case Opcode::I32DivU:
+    case Opcode::I64DivU:
+      WritePrefixBinaryExpr(expr.opcode, "DIV_U");
+      break;
+
+    case Opcode::F32Div:
+    case Opcode::F64Div:
+      WriteInfixBinaryExpr(expr.opcode, "/");
+      break;
+
+    case Opcode::I32RemS:
+      WritePrefixBinaryExpr(expr.opcode, "I32_REM_S");
+      break;
+
+    case Opcode::I64RemS:
+      WritePrefixBinaryExpr(expr.opcode, "I64_REM_S");
+      break;
+
+    case Opcode::I32RemU:
+    case Opcode::I64RemU:
+      WritePrefixBinaryExpr(expr.opcode, "REM_U");
+      break;
+
+    case Opcode::I32And:
+    case Opcode::I64And:
+      WriteInfixBinaryExpr(expr.opcode, "&");
+      break;
+
+    case Opcode::I32Or:
+    case Opcode::I64Or:
+      WriteInfixBinaryExpr(expr.opcode, "|");
+      break;
+
+    case Opcode::I32Xor:
+    case Opcode::I64Xor:
+      WriteInfixBinaryExpr(expr.opcode, "^");
+      break;
+
+    case Opcode::I32Shl:
+    case Opcode::I64Shl:
+      Write(StackVar(1), " <<= (", StackVar(0), " & ",
+            GetShiftMask(expr.opcode.GetResultType()), ");", Newline());
+      DropTypes(1);
+      break;
+
+    case Opcode::I32ShrS:
+    case Opcode::I64ShrS: {
+      Type type = expr.opcode.GetResultType();
+      Write(StackVar(1), " = (", type, ")((", SignedType(type), ")",
+            StackVar(1), " >> (", StackVar(0), " & ", GetShiftMask(type), "));",
+            Newline());
+      DropTypes(1);
+      break;
+    }
+
+    case Opcode::I32ShrU:
+    case Opcode::I64ShrU:
+      Write(StackVar(1), " >>= (", StackVar(0), " & ",
+            GetShiftMask(expr.opcode.GetResultType()), ");", Newline());
+      DropTypes(1);
+      break;
+
+    case Opcode::I32Rotl:
+      WritePrefixBinaryExpr(expr.opcode, "I32_ROTL");
+      break;
+
+    case Opcode::I64Rotl:
+      WritePrefixBinaryExpr(expr.opcode, "I64_ROTL");
+      break;
+
+    case Opcode::I32Rotr:
+      WritePrefixBinaryExpr(expr.opcode, "I32_ROTR");
+      break;
+
+    case Opcode::I64Rotr:
+      WritePrefixBinaryExpr(expr.opcode, "I64_ROTR");
+      break;
+
+    case Opcode::F32Min:
+    case Opcode::F64Min:
+      WritePrefixBinaryExpr(expr.opcode, "FMIN");
+      break;
+
+    case Opcode::F32Max:
+    case Opcode::F64Max:
+      WritePrefixBinaryExpr(expr.opcode, "FMAX");
+      break;
+
+    case Opcode::F32Copysign:
+      WritePrefixBinaryExpr(expr.opcode, "copysignf");
+      break;
+
+    case Opcode::F64Copysign:
+      WritePrefixBinaryExpr(expr.opcode, "copysign");
+      break;
+
+    case Opcode::I8X16Add:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_add");
+      break;
+
+    case Opcode::I8X16AddSatS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_add_sat");
+      break;
+
+    case Opcode::I8X16AddSatU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_add_sat");
+      break;
+
+    case Opcode::I8X16AvgrU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_avgr");
+      break;
+
+    case Opcode::I8X16MaxS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_max");
+      break;
+
+    case Opcode::I8X16MaxU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_max");
+      break;
+
+    case Opcode::I8X16MinS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_min");
+      break;
+
+    case Opcode::I8X16MinU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_min");
+      break;
+
+    case Opcode::I8X16NarrowI16X8S:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_narrow_i16x8");
+      break;
+
+    case Opcode::I8X16NarrowI16X8U:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_narrow_i16x8");
+      break;
+
+    case Opcode::I8X16Shl:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_shl");
+      break;
+
+    case Opcode::I8X16ShrS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_shr");
+      break;
+
+    case Opcode::I8X16ShrU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_shr");
+      break;
+
+    case Opcode::I8X16Sub:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_sub");
+      break;
+
+    case Opcode::I8X16SubSatS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_sub_sat");
+      break;
+
+    case Opcode::I8X16SubSatU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_sub_sat");
+      break;
+
+    case Opcode::I8X16Swizzle:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_swizzle");
+      break;
+
+    case Opcode::I16X8Add:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_add");
+      break;
+
+    case Opcode::I16X8AvgrU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_avgr");
+      break;
+
+    case Opcode::I16X8AddSatS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_add_sat");
+      break;
+
+    case Opcode::I16X8AddSatU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_add_sat");
+      break;
+
+    case Opcode::I16X8ExtmulHighI8X16S:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_extmul_high_i8x16");
+      break;
+
+    case Opcode::I16X8ExtmulHighI8X16U:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_extmul_high_u8x16");
+      break;
+
+    case Opcode::I16X8ExtmulLowI8X16S:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_extmul_low_i8x16");
+      break;
+
+    case Opcode::I16X8ExtmulLowI8X16U:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_extmul_low_u8x16");
+      break;
+
+    case Opcode::I16X8MaxS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_max");
+      break;
+
+    case Opcode::I16X8MaxU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_max");
+      break;
+
+    case Opcode::I16X8MinS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_min");
+      break;
+
+    case Opcode::I16X8MinU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_min");
+      break;
+
+    case Opcode::I16X8Mul:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_mul");
+      break;
+
+    case Opcode::I16X8NarrowI32X4S:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_narrow_i32x4");
+      break;
+
+    case Opcode::I16X8NarrowI32X4U:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_narrow_i32x4");
+      break;
+
+    case Opcode::I16X8Q15mulrSatS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_q15mulr_sat");
+      break;
+
+    case Opcode::I16X8Shl:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_shl");
+      break;
+
+    case Opcode::I16X8ShrS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_shr");
+      break;
+
+    case Opcode::I16X8ShrU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_shr");
+      break;
+
+    case Opcode::I16X8Sub:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_sub");
+      break;
+
+    case Opcode::I16X8SubSatS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_sub_sat");
+      break;
+
+    case Opcode::I16X8SubSatU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_sub_sat");
+      break;
+
+    case Opcode::I32X4Add:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_add");
+      break;
+
+    case Opcode::I32X4DotI16X8S:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_dot_i16x8");
+      break;
+
+    case Opcode::I32X4ExtmulHighI16X8S:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_extmul_high_i16x8");
+      break;
+
+    case Opcode::I32X4ExtmulHighI16X8U:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u32x4_extmul_high_u16x8");
+      break;
+
+    case Opcode::I32X4ExtmulLowI16X8S:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_extmul_low_i16x8");
+      break;
+
+    case Opcode::I32X4ExtmulLowI16X8U:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u32x4_extmul_low_u16x8");
+      break;
+
+    case Opcode::I32X4MaxS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_max");
+      break;
+
+    case Opcode::I32X4MaxU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u32x4_max");
+      break;
+
+    case Opcode::I32X4MinS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_min");
+      break;
+
+    case Opcode::I32X4MinU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u32x4_min");
+      break;
+
+    case Opcode::I32X4Mul:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_mul");
+      break;
+
+    case Opcode::I32X4Shl:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_shl");
+      break;
+
+    case Opcode::I32X4ShrS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_shr");
+      break;
+
+    case Opcode::I32X4ShrU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u32x4_shr");
+      break;
+
+    case Opcode::I32X4Sub:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_sub");
+      break;
+
+    case Opcode::I64X2Add:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_add");
+      break;
+
+    case Opcode::I64X2ExtmulHighI32X4S:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_extmul_high_i32x4");
+      break;
+
+    case Opcode::I64X2ExtmulHighI32X4U:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u64x2_extmul_high_u32x4");
+      break;
+
+    case Opcode::I64X2ExtmulLowI32X4S:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_extmul_low_i32x4");
+      break;
+
+    case Opcode::I64X2ExtmulLowI32X4U:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u64x2_extmul_low_u32x4");
+      break;
+
+    case Opcode::I64X2Mul:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_mul");
+      break;
+
+    case Opcode::I64X2Shl:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_shl");
+      break;
+
+    case Opcode::I64X2ShrS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_shr");
+      break;
+
+    case Opcode::I64X2ShrU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u64x2_shr");
+      break;
+
+    case Opcode::I64X2Sub:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_sub");
+      break;
+
+    case Opcode::F32X4Add:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_add");
+      break;
+
+    case Opcode::F32X4Div:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_div");
+      break;
+
+    case Opcode::F32X4Max:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_max");
+      break;
+
+    case Opcode::F32X4Mul:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_mul");
+      break;
+
+    case Opcode::F32X4Min:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_min");
+      break;
+
+    case Opcode::F32X4PMax:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_pmax");
+      break;
+
+    case Opcode::F32X4PMin:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_pmin");
+      break;
+
+    case Opcode::F32X4Sub:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_sub");
+      break;
+
+    case Opcode::F64X2Add:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_add");
+      break;
+
+    case Opcode::F64X2Div:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_div");
+      break;
+
+    case Opcode::F64X2Max:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_max");
+      break;
+
+    case Opcode::F64X2Mul:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_mul");
+      break;
+
+    case Opcode::F64X2Min:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_min");
+      break;
+
+    case Opcode::F64X2PMax:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_pmax");
+      break;
+
+    case Opcode::F64X2PMin:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_pmin");
+      break;
+
+    case Opcode::F64X2Sub:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_sub");
+      break;
+
+    case Opcode::V128And:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_v128_and");
+      break;
+
+    case Opcode::V128Andnot:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_v128_andnot");
+      break;
+
+    case Opcode::V128Or:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_v128_or");
+      break;
+
+    case Opcode::V128Xor:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_v128_xor");
+      break;
+
+    default:
+      WABT_UNREACHABLE;
+  }
+}
+
+void CWriter::Write(const CompareExpr& expr) {
+  switch (expr.opcode) {
+    case Opcode::I32Eq:
+    case Opcode::I64Eq:
+    case Opcode::F32Eq:
+    case Opcode::F64Eq:
+      WriteInfixBinaryExpr(expr.opcode, "==", AssignOp::Disallowed);
+      break;
+
+    case Opcode::I32Ne:
+    case Opcode::I64Ne:
+    case Opcode::F32Ne:
+    case Opcode::F64Ne:
+      WriteInfixBinaryExpr(expr.opcode, "!=", AssignOp::Disallowed);
+      break;
+
+    case Opcode::I32LtS:
+    case Opcode::I64LtS:
+      WriteSignedBinaryExpr(expr.opcode, "<");
+      break;
+
+    case Opcode::I32LtU:
+    case Opcode::I64LtU:
+    case Opcode::F32Lt:
+    case Opcode::F64Lt:
+      WriteInfixBinaryExpr(expr.opcode, "<", AssignOp::Disallowed);
+      break;
+
+    case Opcode::I32LeS:
+    case Opcode::I64LeS:
+      WriteSignedBinaryExpr(expr.opcode, "<=");
+      break;
+
+    case Opcode::I32LeU:
+    case Opcode::I64LeU:
+    case Opcode::F32Le:
+    case Opcode::F64Le:
+      WriteInfixBinaryExpr(expr.opcode, "<=", AssignOp::Disallowed);
+      break;
+
+    case Opcode::I32GtS:
+    case Opcode::I64GtS:
+      WriteSignedBinaryExpr(expr.opcode, ">");
+      break;
+
+    case Opcode::I32GtU:
+    case Opcode::I64GtU:
+    case Opcode::F32Gt:
+    case Opcode::F64Gt:
+      WriteInfixBinaryExpr(expr.opcode, ">", AssignOp::Disallowed);
+      break;
+
+    case Opcode::I32GeS:
+    case Opcode::I64GeS:
+      WriteSignedBinaryExpr(expr.opcode, ">=");
+      break;
+
+    case Opcode::I32GeU:
+    case Opcode::I64GeU:
+    case Opcode::F32Ge:
+    case Opcode::F64Ge:
+      WriteInfixBinaryExpr(expr.opcode, ">=", AssignOp::Disallowed);
+      break;
+
+    case Opcode::I8X16Eq:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_eq");
+      break;
+
+    case Opcode::I8X16GeS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_ge");
+      break;
+
+    case Opcode::I8X16GeU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_ge");
+      break;
+
+    case Opcode::I8X16GtS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_gt");
+      break;
+
+    case Opcode::I8X16GtU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_gt");
+      break;
+
+    case Opcode::I8X16LeS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_le");
+      break;
+
+    case Opcode::I8X16LeU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_le");
+      break;
+
+    case Opcode::I8X16LtS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_lt");
+      break;
+
+    case Opcode::I8X16LtU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u8x16_lt");
+      break;
+
+    case Opcode::I8X16Ne:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i8x16_ne");
+      break;
+
+    case Opcode::I16X8Eq:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_eq");
+      break;
+
+    case Opcode::I16X8GeS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_ge");
+      break;
+
+    case Opcode::I16X8GeU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_ge");
+      break;
+
+    case Opcode::I16X8GtS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_gt");
+      break;
+    case Opcode::I16X8GtU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_gt");
+      break;
+
+    case Opcode::I16X8LeS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_le");
+      break;
+
+    case Opcode::I16X8LeU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_le");
+      break;
+
+    case Opcode::I16X8LtS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_lt");
+      break;
+
+    case Opcode::I16X8LtU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u16x8_lt");
+      break;
+
+    case Opcode::I16X8Ne:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i16x8_ne");
+      break;
+
+    case Opcode::I32X4Eq:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_eq");
+      break;
+
+    case Opcode::I32X4GeS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_ge");
+      break;
+
+    case Opcode::I32X4GeU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u32x4_ge");
+      break;
+
+    case Opcode::I32X4GtS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_gt");
+      break;
+
+    case Opcode::I32X4GtU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u32x4_gt");
+      break;
+
+    case Opcode::I32X4LeS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_le");
+      break;
+
+    case Opcode::I32X4LeU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u32x4_le");
+      break;
+
+    case Opcode::I32X4LtS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_lt");
+      break;
+
+    case Opcode::I32X4LtU:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_u32x4_lt");
+      break;
+
+    case Opcode::I32X4Ne:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i32x4_ne");
+      break;
+
+    case Opcode::I64X2Eq:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_eq");
+      break;
+
+    case Opcode::I64X2GeS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_ge");
+      break;
+
+    case Opcode::I64X2GtS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_gt");
+      break;
+
+    case Opcode::I64X2LeS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_le");
+      break;
+
+    case Opcode::I64X2LtS:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_lt");
+      break;
+
+    case Opcode::I64X2Ne:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_i64x2_ne");
+      break;
+
+    case Opcode::F32X4Eq:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_eq");
+      break;
+
+    case Opcode::F32X4Ge:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_ge");
+      break;
+
+    case Opcode::F32X4Gt:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_gt");
+      break;
+
+    case Opcode::F32X4Le:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_le");
+      break;
+
+    case Opcode::F32X4Lt:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_lt");
+      break;
+
+    case Opcode::F32X4Ne:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f32x4_ne");
+      break;
+
+    case Opcode::F64X2Eq:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_eq");
+      break;
+
+    case Opcode::F64X2Ge:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_ge");
+      break;
+
+    case Opcode::F64X2Gt:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_gt");
+      break;
+
+    case Opcode::F64X2Le:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_le");
+      break;
+
+    case Opcode::F64X2Lt:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_lt");
+      break;
+
+    case Opcode::F64X2Ne:
+      WritePrefixBinaryExpr(expr.opcode, "simde_wasm_f64x2_ne");
+      break;
+
+    default:
+      WABT_UNREACHABLE;
+  }
+}
+
+void CWriter::Write(const ConvertExpr& expr) {
+  switch (expr.opcode) {
+    case Opcode::I32Eqz:
+    case Opcode::I64Eqz:
+      WriteSimpleUnaryExpr(expr.opcode, "!");
+      break;
+
+    case Opcode::I64ExtendI32S:
+      WriteSimpleUnaryExpr(expr.opcode, "(u64)(s64)(s32)");
+      break;
+
+    case Opcode::I64ExtendI32U:
+      WriteSimpleUnaryExpr(expr.opcode, "(u64)");
+      break;
+
+    case Opcode::I32WrapI64:
+      WriteSimpleUnaryExpr(expr.opcode, "(u32)");
+      break;
+
+    case Opcode::I32TruncF32S:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_TRUNC_S_F32");
+      break;
+
+    case Opcode::I64TruncF32S:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_TRUNC_S_F32");
+      break;
+
+    case Opcode::I32TruncF64S:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_TRUNC_S_F64");
+      break;
+
+    case Opcode::I64TruncF64S:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_TRUNC_S_F64");
+      break;
+
+    case Opcode::I32TruncF32U:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_TRUNC_U_F32");
+      break;
+
+    case Opcode::I64TruncF32U:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_TRUNC_U_F32");
+      break;
+
+    case Opcode::I32TruncF64U:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_TRUNC_U_F64");
+      break;
+
+    case Opcode::I64TruncF64U:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_TRUNC_U_F64");
+      break;
+
+    case Opcode::I32TruncSatF32S:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_TRUNC_SAT_S_F32");
+      break;
+
+    case Opcode::I64TruncSatF32S:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_TRUNC_SAT_S_F32");
+      break;
+
+    case Opcode::I32TruncSatF64S:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_TRUNC_SAT_S_F64");
+      break;
+
+    case Opcode::I64TruncSatF64S:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_TRUNC_SAT_S_F64");
+      break;
+
+    case Opcode::I32TruncSatF32U:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_TRUNC_SAT_U_F32");
+      break;
+
+    case Opcode::I64TruncSatF32U:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_TRUNC_SAT_U_F32");
+      break;
+
+    case Opcode::I32TruncSatF64U:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_TRUNC_SAT_U_F64");
+      break;
+
+    case Opcode::I64TruncSatF64U:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_TRUNC_SAT_U_F64");
+      break;
+
+    case Opcode::F32ConvertI32S:
+      WriteSimpleUnaryExpr(expr.opcode, "(f32)(s32)");
+      break;
+
+    case Opcode::F32ConvertI64S:
+      WriteSimpleUnaryExpr(expr.opcode, "(f32)(s64)");
+      break;
+
+    case Opcode::F32ConvertI32U:
+      WriteSimpleUnaryExpr(expr.opcode, "(f32)");
+      break;
+
+    case Opcode::F32DemoteF64:
+      WriteSimpleUnaryExpr(expr.opcode, "(f32)wasm_quiet");
+      break;
+
+    case Opcode::F32ConvertI64U:
+      // TODO(binji): This needs to be handled specially (see
+      // wabt_convert_uint64_to_float).
+      WriteSimpleUnaryExpr(expr.opcode, "(f32)");
+      break;
+
+    case Opcode::F64ConvertI32S:
+      WriteSimpleUnaryExpr(expr.opcode, "(f64)(s32)");
+      break;
+
+    case Opcode::F64ConvertI64S:
+      WriteSimpleUnaryExpr(expr.opcode, "(f64)(s64)");
+      break;
+
+    case Opcode::F64ConvertI32U:
+      WriteSimpleUnaryExpr(expr.opcode, "(f64)");
+      break;
+
+    case Opcode::F64PromoteF32:
+      WriteSimpleUnaryExpr(expr.opcode, "(f64)wasm_quietf");
+      break;
+
+    case Opcode::F64ConvertI64U:
+      // TODO(binji): This needs to be handled specially (see
+      // wabt_convert_uint64_to_double).
+      WriteSimpleUnaryExpr(expr.opcode, "(f64)");
+      break;
+
+    case Opcode::F32ReinterpretI32:
+      WriteSimpleUnaryExpr(expr.opcode, "f32_reinterpret_i32");
+      break;
+
+    case Opcode::I32ReinterpretF32:
+      WriteSimpleUnaryExpr(expr.opcode, "i32_reinterpret_f32");
+      break;
+
+    case Opcode::F64ReinterpretI64:
+      WriteSimpleUnaryExpr(expr.opcode, "f64_reinterpret_i64");
+      break;
+
+    case Opcode::I64ReinterpretF64:
+      WriteSimpleUnaryExpr(expr.opcode, "i64_reinterpret_f64");
+      break;
+
+    case Opcode::I32X4TruncSatF32X4S:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i32x4_trunc_sat_f32x4");
+      break;
+
+    case Opcode::I32X4TruncSatF32X4U:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_u32x4_trunc_sat_f32x4");
+      break;
+
+    case Opcode::I32X4TruncSatF64X2SZero:
+      WriteSimpleUnaryExpr(expr.opcode,
+                           "simde_wasm_i32x4_trunc_sat_f64x2_zero");
+      break;
+
+    case Opcode::I32X4TruncSatF64X2UZero:
+      WriteSimpleUnaryExpr(expr.opcode,
+                           "simde_wasm_u32x4_trunc_sat_f64x2_zero");
+      break;
+
+    case Opcode::F32X4ConvertI32X4S:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_convert_i32x4");
+      break;
+
+    case Opcode::F32X4ConvertI32X4U:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_convert_u32x4");
+      break;
+
+    case Opcode::F32X4DemoteF64X2Zero:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_demote_f64x2_zero");
+      break;
+
+    case Opcode::F64X2ConvertLowI32X4S:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_convert_low_i32x4");
+      break;
+
+    case Opcode::F64X2ConvertLowI32X4U:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_convert_low_u32x4");
+      break;
+
+    case Opcode::F64X2PromoteLowF32X4:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_promote_low_f32x4");
+      break;
+
+    default:
+      WABT_UNREACHABLE;
+  }
+}
+
+void CWriter::Write(const LoadExpr& expr) {
+  const char* func = nullptr;
+  // clang-format off
+  switch (expr.opcode) {
+    case Opcode::I32Load: func = "i32_load"; break;
+    case Opcode::I64Load: func = "i64_load"; break;
+    case Opcode::F32Load: func = "f32_load"; break;
+    case Opcode::F64Load: func = "f64_load"; break;
+    case Opcode::I32Load8S: func = "i32_load8_s"; break;
+    case Opcode::I64Load8S: func = "i64_load8_s"; break;
+    case Opcode::I32Load8U: func = "i32_load8_u"; break;
+    case Opcode::I64Load8U: func = "i64_load8_u"; break;
+    case Opcode::I32Load16S: func = "i32_load16_s"; break;
+    case Opcode::I64Load16S: func = "i64_load16_s"; break;
+    case Opcode::I32Load16U: func = "i32_load16_u"; break;
+    case Opcode::I64Load16U: func = "i64_load16_u"; break;
+    case Opcode::I64Load32S: func = "i64_load32_s"; break;
+    case Opcode::I64Load32U: func = "i64_load32_u"; break;
+    case Opcode::V128Load: func = "v128_load"; break;
+    case Opcode::V128Load8X8S: func = "i16x8_load8x8"; break;
+    case Opcode::V128Load8X8U: func = "u16x8_load8x8"; break;
+    case Opcode::V128Load16X4S: func = "i32x4_load16x4"; break;
+    case Opcode::V128Load16X4U: func = "u32x4_load16x4"; break;
+    case Opcode::V128Load32X2S: func = "i64x2_load32x2"; break;
+    case Opcode::V128Load32X2U: func = "u64x2_load32x2"; break;
+
+    default:
+      WABT_UNREACHABLE;
+  }
+  // clang-format on
+
+  Memory* memory = module_->memories[module_->GetMemoryIndex(expr.memidx)];
+
+  Type result_type = expr.opcode.GetResultType();
+  Write(StackVar(0, result_type), " = ", func, "(",
+        ExternalInstancePtr(ModuleFieldType::Memory, memory->name), ", (u64)(",
+        StackVar(0), ")");
+  if (expr.offset != 0)
+    Write(" + ", expr.offset, "u");
+  Write(");", Newline());
+  DropTypes(1);
+  PushType(result_type);
+}
+
+void CWriter::Write(const StoreExpr& expr) {
+  const char* func = nullptr;
+  // clang-format off
+  switch (expr.opcode) {
+    case Opcode::I32Store: func = "i32_store"; break;
+    case Opcode::I64Store: func = "i64_store"; break;
+    case Opcode::F32Store: func = "f32_store"; break;
+    case Opcode::F64Store: func = "f64_store"; break;
+    case Opcode::I32Store8: func = "i32_store8"; break;
+    case Opcode::I64Store8: func = "i64_store8"; break;
+    case Opcode::I32Store16: func = "i32_store16"; break;
+    case Opcode::I64Store16: func = "i64_store16"; break;
+    case Opcode::I64Store32: func = "i64_store32"; break;
+    case Opcode::V128Store: func = "v128_store"; break;
+
+    default:
+      WABT_UNREACHABLE;
+  }
+  // clang-format on
+
+  Memory* memory = module_->memories[module_->GetMemoryIndex(expr.memidx)];
+
+  Write(func, "(", ExternalInstancePtr(ModuleFieldType::Memory, memory->name),
+        ", (u64)(", StackVar(1), ")");
+  if (expr.offset != 0)
+    Write(" + ", expr.offset);
+  Write(", ", StackVar(0), ");", Newline());
+  DropTypes(2);
+}
+
+void CWriter::Write(const UnaryExpr& expr) {
+  switch (expr.opcode) {
+    case Opcode::I32Clz:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_CLZ");
+      break;
+
+    case Opcode::I64Clz:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_CLZ");
+      break;
+
+    case Opcode::I32Ctz:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_CTZ");
+      break;
+
+    case Opcode::I64Ctz:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_CTZ");
+      break;
+
+    case Opcode::I32Popcnt:
+      WriteSimpleUnaryExpr(expr.opcode, "I32_POPCNT");
+      break;
+
+    case Opcode::I64Popcnt:
+      WriteSimpleUnaryExpr(expr.opcode, "I64_POPCNT");
+      break;
+
+    case Opcode::F32Neg:
+    case Opcode::F64Neg:
+      WriteSimpleUnaryExpr(expr.opcode, "-");
+      break;
+
+    case Opcode::F32Abs:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_fabsf");
+      break;
+
+    case Opcode::F64Abs:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_fabs");
+      break;
+
+    case Opcode::F32Sqrt:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_sqrtf");
+      break;
+
+    case Opcode::F64Sqrt:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_sqrt");
+      break;
+
+    case Opcode::F32Ceil:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_ceilf");
+      break;
+
+    case Opcode::F64Ceil:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_ceil");
+      break;
+
+    case Opcode::F32Floor:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_floorf");
+      break;
+
+    case Opcode::F64Floor:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_floor");
+      break;
+
+    case Opcode::F32Trunc:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_truncf");
+      break;
+
+    case Opcode::F64Trunc:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_trunc");
+      break;
+
+    case Opcode::F32Nearest:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_nearbyintf");
+      break;
+
+    case Opcode::F64Nearest:
+      WriteSimpleUnaryExpr(expr.opcode, "wasm_nearbyint");
+      break;
+
+    case Opcode::I32Extend8S:
+      WriteSimpleUnaryExpr(expr.opcode, "(u32)(s32)(s8)(u8)");
+      break;
+
+    case Opcode::I32Extend16S:
+      WriteSimpleUnaryExpr(expr.opcode, "(u32)(s32)(s16)(u16)");
+      break;
+
+    case Opcode::I64Extend8S:
+      WriteSimpleUnaryExpr(expr.opcode, "(u64)(s64)(s8)(u8)");
+      break;
+
+    case Opcode::I64Extend16S:
+      WriteSimpleUnaryExpr(expr.opcode, "(u64)(s64)(s16)(u16)");
+      break;
+
+    case Opcode::I64Extend32S:
+      WriteSimpleUnaryExpr(expr.opcode, "(u64)(s64)(s32)(u32)");
+      break;
+
+    case Opcode::I8X16Abs:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i8x16_abs");
+      break;
+
+    case Opcode::I8X16AllTrue:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i8x16_all_true");
+      break;
+
+    case Opcode::I8X16Bitmask:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i8x16_bitmask");
+      break;
+
+    case Opcode::I8X16Neg:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i8x16_neg");
+      break;
+
+    case Opcode::I8X16Popcnt:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i8x16_popcnt");
+      break;
+
+    case Opcode::I8X16Splat:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i8x16_splat");
+      break;
+
+    case Opcode::I16X8Abs:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i16x8_abs");
+      break;
+
+    case Opcode::I16X8AllTrue:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i16x8_all_true");
+      break;
+
+    case Opcode::I16X8Bitmask:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i16x8_bitmask");
+      break;
+
+    case Opcode::I16X8ExtaddPairwiseI8X16S:
+      WriteSimpleUnaryExpr(expr.opcode,
+                           "simde_wasm_i16x8_extadd_pairwise_i8x16");
+      break;
+
+    case Opcode::I16X8ExtaddPairwiseI8X16U:
+      WriteSimpleUnaryExpr(expr.opcode,
+                           "simde_wasm_u16x8_extadd_pairwise_u8x16");
+      break;
+
+    case Opcode::I16X8ExtendHighI8X16S:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i16x8_extend_high_i8x16");
+      break;
+
+    case Opcode::I16X8ExtendHighI8X16U:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_u16x8_extend_high_u8x16");
+      break;
+
+    case Opcode::I16X8ExtendLowI8X16S:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i16x8_extend_low_i8x16");
+      break;
+
+    case Opcode::I16X8ExtendLowI8X16U:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_u16x8_extend_low_u8x16");
+      break;
+
+    case Opcode::I16X8Neg:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i16x8_neg");
+      break;
+
+    case Opcode::I16X8Splat:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i16x8_splat");
+      break;
+
+    case Opcode::I32X4Abs:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i32x4_abs");
+      break;
+
+    case Opcode::I32X4AllTrue:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i32x4_all_true");
+      break;
+
+    case Opcode::I32X4Bitmask:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i32x4_bitmask");
+      break;
+
+    case Opcode::I32X4ExtaddPairwiseI16X8S:
+      WriteSimpleUnaryExpr(expr.opcode,
+                           "simde_wasm_i32x4_extadd_pairwise_i16x8");
+      break;
+
+    case Opcode::I32X4ExtaddPairwiseI16X8U:
+      WriteSimpleUnaryExpr(expr.opcode,
+                           "simde_wasm_u32x4_extadd_pairwise_u16x8");
+      break;
+
+    case Opcode::I32X4ExtendHighI16X8S:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i32x4_extend_high_i16x8");
+      break;
+
+    case Opcode::I32X4ExtendHighI16X8U:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_u32x4_extend_high_u16x8");
+      break;
+
+    case Opcode::I32X4ExtendLowI16X8S:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i32x4_extend_low_i16x8");
+      break;
+
+    case Opcode::I32X4ExtendLowI16X8U:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_u32x4_extend_low_u16x8");
+      break;
+
+    case Opcode::I32X4Neg:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i32x4_neg");
+      break;
+
+    case Opcode::I32X4Splat:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i32x4_splat");
+      break;
+
+    case Opcode::I64X2Abs:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i64x2_abs");
+      break;
+
+    case Opcode::I64X2AllTrue:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i64x2_all_true");
+      break;
+
+    case Opcode::I64X2Bitmask:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i64x2_bitmask");
+      break;
+
+    case Opcode::I64X2ExtendHighI32X4S:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i64x2_extend_high_i32x4");
+      break;
+
+    case Opcode::I64X2ExtendHighI32X4U:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_u64x2_extend_high_u32x4");
+      break;
+
+    case Opcode::I64X2ExtendLowI32X4S:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i64x2_extend_low_i32x4");
+      break;
+
+    case Opcode::I64X2ExtendLowI32X4U:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_u64x2_extend_low_u32x4");
+      break;
+
+    case Opcode::I64X2Neg:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i64x2_neg");
+      break;
+
+    case Opcode::I64X2Splat:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_i64x2_splat");
+      break;
+
+    case Opcode::F32X4Abs:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_abs");
+      break;
+
+    case Opcode::F32X4Ceil:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_ceil");
+      break;
+
+    case Opcode::F32X4Floor:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_floor");
+      break;
+
+    case Opcode::F32X4Nearest:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_nearest");
+      break;
+
+    case Opcode::F32X4Neg:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_neg");
+      break;
+
+    case Opcode::F32X4Splat:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_splat");
+      break;
+
+    case Opcode::F32X4Sqrt:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_sqrt");
+      break;
+
+    case Opcode::F32X4Trunc:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f32x4_trunc");
+      break;
+
+    case Opcode::F64X2Abs:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_abs");
+      break;
+
+    case Opcode::F64X2Ceil:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_ceil");
+      break;
+
+    case Opcode::F64X2Floor:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_floor");
+      break;
+
+    case Opcode::F64X2Nearest:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_nearest");
+      break;
+
+    case Opcode::F64X2Neg:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_neg");
+      break;
+
+    case Opcode::F64X2Splat:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_splat");
+      break;
+
+    case Opcode::F64X2Sqrt:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_sqrt");
+      break;
+
+    case Opcode::F64X2Trunc:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_f64x2_trunc");
+      break;
+
+    case Opcode::V128AnyTrue:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_v128_any_true");
+      break;
+
+    case Opcode::V128Not:
+      WriteSimpleUnaryExpr(expr.opcode, "simde_wasm_v128_not");
+      break;
+
+    default:
+      WABT_UNREACHABLE;
+  }
+}
+
+void CWriter::Write(const TernaryExpr& expr) {
+  switch (expr.opcode) {
+    case Opcode::V128BitSelect: {
+      Type result_type = expr.opcode.GetResultType();
+      Write(StackVar(2, result_type), " = ", "simde_wasm_v128_bitselect", "(",
+            StackVar(2), ", ", StackVar(1), ", ", StackVar(0), ");", Newline());
+      DropTypes(3);
+      PushType(result_type);
+      break;
+    }
+    default:
+      WABT_UNREACHABLE;
+  }
+}
+
+void CWriter::Write(const SimdLaneOpExpr& expr) {
+  Type result_type = expr.opcode.GetResultType();
+
+  switch (expr.opcode) {
+    case Opcode::I8X16ExtractLaneS: {
+      Write(StackVar(0, result_type), " = simde_wasm_i8x16_extract_lane(",
+            StackVar(0), ", ", expr.val, ");", Newline());
+      DropTypes(1);
+      break;
+    }
+    case Opcode::I8X16ExtractLaneU: {
+      Write(StackVar(0, result_type), " = simde_wasm_u8x16_extract_lane(",
+            StackVar(0), ", ", expr.val, ");", Newline());
+      DropTypes(1);
+      break;
+    }
+    case Opcode::I16X8ExtractLaneS: {
+      Write(StackVar(0, result_type), " = simde_wasm_i16x8_extract_lane(",
+            StackVar(0), ", ", expr.val, ");", Newline());
+      DropTypes(1);
+      break;
+    }
+    case Opcode::I16X8ExtractLaneU: {
+      Write(StackVar(0, result_type), " = simde_wasm_u16x8_extract_lane(",
+            StackVar(0), ", ", expr.val, ");", Newline());
+      DropTypes(1);
+      break;
+    }
+    case Opcode::I32X4ExtractLane: {
+      Write(StackVar(0, result_type), " = simde_wasm_i32x4_extract_lane(",
+            StackVar(0), ", ", expr.val, ");", Newline());
+      DropTypes(1);
+      break;
+    }
+    case Opcode::I64X2ExtractLane: {
+      Write(StackVar(0, result_type), " = simde_wasm_i64x2_extract_lane(",
+            StackVar(0), ", ", expr.val, ");", Newline());
+      DropTypes(1);
+      break;
+    }
+    case Opcode::F32X4ExtractLane: {
+      Write(StackVar(0, result_type), " = simde_wasm_f32x4_extract_lane(",
+            StackVar(0), ", ", expr.val, ");", Newline());
+      DropTypes(1);
+      break;
+    }
+    case Opcode::F64X2ExtractLane: {
+      Write(StackVar(0, result_type), " = simde_wasm_f64x2_extract_lane(",
+            StackVar(0), ", ", expr.val, ");", Newline());
+      DropTypes(1);
+      break;
+    }
+    case Opcode::I8X16ReplaceLane: {
+      Write(StackVar(1, result_type), " = simde_wasm_i8x16_replace_lane(",
+            StackVar(1), ", ", expr.val, ", ", StackVar(0), ");", Newline());
+      DropTypes(2);
+      break;
+    }
+    case Opcode::I16X8ReplaceLane: {
+      Write(StackVar(1, result_type), " = simde_wasm_i16x8_replace_lane(",
+            StackVar(1), ", ", expr.val, ", ", StackVar(0), ");", Newline());
+      DropTypes(2);
+      break;
+    }
+    case Opcode::I32X4ReplaceLane: {
+      Write(StackVar(1, result_type), " = simde_wasm_i32x4_replace_lane(",
+            StackVar(1), ", ", expr.val, ", ", StackVar(0), ");", Newline());
+      DropTypes(2);
+      break;
+    }
+    case Opcode::I64X2ReplaceLane: {
+      Write(StackVar(1, result_type), " = simde_wasm_i64x2_replace_lane(",
+            StackVar(1), ", ", expr.val, ", ", StackVar(0), ");", Newline());
+      DropTypes(2);
+      break;
+    }
+    case Opcode::F32X4ReplaceLane: {
+      Write(StackVar(1, result_type), " = simde_wasm_f32x4_replace_lane(",
+            StackVar(1), ", ", expr.val, ", ", StackVar(0), ");", Newline());
+      DropTypes(2);
+      break;
+    }
+    case Opcode::F64X2ReplaceLane: {
+      Write(StackVar(1, result_type), " = simde_wasm_f64x2_replace_lane(",
+            StackVar(1), ", ", expr.val, ", ", StackVar(0), ");", Newline());
+      DropTypes(2);
+      break;
+    }
+    default:
+      WABT_UNREACHABLE;
+  }
+
+  PushType(result_type);
+}
+
+void CWriter::Write(const SimdLoadLaneExpr& expr) {
+  const char* func = nullptr;
+  // clang-format off
+  switch (expr.opcode) {
+    case Opcode::V128Load8Lane: func = "v128_load8_lane"; break;
+    case Opcode::V128Load16Lane: func = "v128_load16_lane"; break;
+    case Opcode::V128Load32Lane: func = "v128_load32_lane"; break;
+    case Opcode::V128Load64Lane: func = "v128_load64_lane"; break;
+    default:
+      WABT_UNREACHABLE;
+  }
+  // clang-format on
+  Memory* memory = module_->memories[module_->GetMemoryIndex(expr.memidx)];
+  Type result_type = expr.opcode.GetResultType();
+  Write(StackVar(1, result_type), " = ", func, expr.val, "(",
+        ExternalInstancePtr(ModuleFieldType::Memory, memory->name), ", (u64)(",
+        StackVar(1), ")");
+
+  if (expr.offset != 0)
+    Write(" + ", expr.offset, "u");
+  Write(", ", StackVar(0));
+  Write(");", Newline());
+
+  DropTypes(2);
+  PushType(result_type);
+}
+
+void CWriter::Write(const SimdStoreLaneExpr& expr) {
+  const char* func = nullptr;
+  // clang-format off
+  switch (expr.opcode) {
+    case Opcode::V128Store8Lane: func = "v128_store8_lane"; break;
+    case Opcode::V128Store16Lane: func = "v128_store16_lane"; break;
+    case Opcode::V128Store32Lane: func = "v128_store32_lane"; break;
+    case Opcode::V128Store64Lane: func = "v128_store64_lane"; break;
+    default:
+      WABT_UNREACHABLE;
+  }
+  // clang-format on
+  Memory* memory = module_->memories[module_->GetMemoryIndex(expr.memidx)];
+
+  Write(func, expr.val, "(",
+        ExternalInstancePtr(ModuleFieldType::Memory, memory->name), ", (u64)(",
+        StackVar(1), ")");
+
+  if (expr.offset != 0)
+    Write(" + ", expr.offset, "u");
+  Write(", ", StackVar(0));
+  Write(");", Newline());
+
+  DropTypes(2);
+}
+
+void CWriter::Write(const SimdShuffleOpExpr& expr) {
+  Type result_type = expr.opcode.GetResultType();
+  switch (expr.opcode) {
+    case Opcode::I8X16Shuffle: {
+      Write(StackVar(1, result_type), " = simde_wasm_i8x16_shuffle(",
+            StackVar(1), ", ", StackVar(0), ", ", expr.val.u8(0), ", ",
+            expr.val.u8(1), ", ", expr.val.u8(2), ", ", expr.val.u8(3), ", ",
+            expr.val.u8(4), ", ", expr.val.u8(5), ", ", expr.val.u8(6), ", ",
+            expr.val.u8(7), ", ", expr.val.u8(8), ", ", expr.val.u8(9), ", ",
+            expr.val.u8(10), ", ", expr.val.u8(11), ", ", expr.val.u8(12), ", ",
+            expr.val.u8(13), ", ", expr.val.u8(14), ", ", expr.val.u8(15), ");",
+            Newline());
+      DropTypes(2);
+      break;
+    }
+    default:
+      WABT_UNREACHABLE;
+  }
+  PushType(result_type);
+}
+
+void CWriter::Write(const LoadSplatExpr& expr) {
+  Memory* memory = module_->memories[module_->GetMemoryIndex(expr.memidx)];
+
+  const char* func = nullptr;
+  // clang-format off
+  switch (expr.opcode) {
+    case Opcode::V128Load8Splat: func = "v128_load8_splat"; break;
+    case Opcode::V128Load16Splat: func = "v128_load16_splat"; break;
+    case Opcode::V128Load32Splat: func = "v128_load32_splat"; break;
+    case Opcode::V128Load64Splat: func = "v128_load64_splat"; break;
+    default:
+      WABT_UNREACHABLE;
+  }
+  // clang-format on
+  Type result_type = expr.opcode.GetResultType();
+  Write(StackVar(0, result_type), " = ", func, "(",
+        ExternalInstancePtr(ModuleFieldType::Memory, memory->name), ", (u64)(",
+        StackVar(0), ")");
+  if (expr.offset != 0)
+    Write(" + ", expr.offset);
+  Write(");", Newline());
+
+  DropTypes(1);
+  PushType(result_type);
+}
+
+void CWriter::Write(const LoadZeroExpr& expr) {
+  Memory* memory = module_->memories[module_->GetMemoryIndex(expr.memidx)];
+
+  const char* func = nullptr;
+  // clang-format off
+  switch (expr.opcode) {
+    case Opcode::V128Load32Zero: func = "v128_load32_zero"; break;
+    case Opcode::V128Load64Zero: func = "v128_load64_zero"; break;
+    default:
+      WABT_UNREACHABLE;
+  }
+  // clang-format on
+
+  Type result_type = expr.opcode.GetResultType();
+  Write(StackVar(0, result_type), " = ", func, "(",
+        ExternalInstancePtr(ModuleFieldType::Memory, memory->name), ", (u64)(",
+        StackVar(0), ")");
+  if (expr.offset != 0)
+    Write(" + ", expr.offset);
+  Write(");", Newline());
+
+  DropTypes(1);
+  PushType(result_type);
+}
+
+void CWriter::ReserveExportNames() {
+  for (const Export* export_ : module_->exports) {
+    ReserveExportName(export_->name);
+  }
+}
+
+void CWriter::WriteCHeader() {
+  ReserveExportNames();
+
+  stream_ = h_stream_;
+  std::string guard = GenerateHeaderGuard();
+  Write("/* Automatically generated by wasm2c */", Newline());
+  Write("#ifndef ", guard, Newline());
+  Write("#define ", guard, Newline());
+  Write(Newline());
+  ComputeSimdScope();
+  WriteHeaderIncludes();
+  Write(s_header_top);
+  Write(Newline());
+  WriteModuleInstance();
+  WriteInitDecl();
+  WriteFreeDecl();
+  WriteGetFuncTypeDecl();
+  WriteMultivalueTypes();
+  WriteImports();
+  WriteImportProperties(CWriterPhase::Declarations);
+  WriteExports(CWriterPhase::Declarations);
+  Write(Newline());
+  Write(s_header_bottom);
+  Write(Newline(), "#endif  /* ", guard, " */", Newline());
+}
+
+void CWriter::WriteCSource() {
+  /* Write the "top" to h_impl stream */
+  stream_ = h_impl_stream_;
+  Write("/* Automatically generated by wasm2c */", Newline());
+  WriteSourceTop();
+
+  /* Write module-wide declarations to impl header */
+  WriteFuncTypeDecls();
+  WriteTagTypes();
+  WriteTagDecls();
+  WriteFuncDeclarations();
+  WriteDataInitializerDecls();
+  WriteElemInitializerDecls();
+
+  /* Write the module-wide material to the first output stream */
+  stream_ = c_streams_.front();
+  WriteMultiCTop();
+  WriteFuncTypes();
+  WriteTags();
+  WriteGlobalInitializers();
+  WriteDataInitializers();
+  WriteElemInitializers();
+  WriteExports(CWriterPhase::Definitions);
+  WriteInitInstanceImport();
+  WriteImportProperties(CWriterPhase::Definitions);
+  WriteInit();
+  WriteFree();
+  WriteGetFuncType();
+
+  /* Write function bodies across the different output streams */
+  WriteFuncs();
+
+  /* For any empty .c output, write a dummy typedef to avoid gcc warning */
+  WriteMultiCTopEmpty();
+}
+
+Result CWriter::WriteModule(const Module& module) {
+  WABT_USE(options_);
+  module_ = &module;
+  WriteCHeader();
+  WriteCSource();
+  return result_;
+}
+
+// static
+const char* CWriter::GetReferenceTypeName(const Type& type) {
+  switch (type) {
+    case Type::FuncRef:
+      return "funcref";
+    case Type::ExternRef:
+      return "externref";
+    default:
+      WABT_UNREACHABLE;
+  }
+}
+
+// static
+const char* CWriter::GetReferenceNullValue(const Type& type) {
+  switch (type) {
+    case Type::FuncRef:
+      return "wasm_rt_funcref_null_value";
+    case Type::ExternRef:
+      return "wasm_rt_externref_null_value";
+    default:
+      WABT_UNREACHABLE;
+  }
+}
+
+const char* CWriter::InternalSymbolScope() const {
+  if (c_streams_.size() == 1) {
+    return "static ";
+  } else {
+    return "";
+  }
+}
+
+}  // end anonymous namespace
+
+Result WriteC(std::vector<Stream*>&& c_streams,
+              Stream* h_stream,
+              Stream* h_impl_stream,
+              const char* header_name,
+              const char* header_impl_name,
+              const Module* module,
+              const WriteCOptions& options) {
+  CWriter c_writer(std::move(c_streams), h_stream, h_impl_stream, header_name,
+                   header_impl_name, options);
+  return c_writer.WriteModule(*module);
+}
+
+}  // namespace wabt
-- 
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