llvm/lib/ObjCopy/wasm/WasmWriter.h

   1 //===- WasmWriter.h ---------------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIB_OBJCOPY_WASM_WASMWRITER_H
  10 #define LLVM_LIB_OBJCOPY_WASM_WASMWRITER_H
  11
  12 #include "WasmObject.h"
  13 #include <cstdint>
  14 #include <vector>
  15
  16 namespace llvm {
  17 namespace objcopy {
  18 namespace wasm {
  19
  20 class Writer {
  21 public:
  22   Writer(Object &Obj, raw_ostream &Out) : Obj(Obj), Out(Out) {}
  23   Error write();
  24
  25 private:
  26   using SectionHeader = SmallVector<char, 8>;
  27   Object &Obj;
  28   raw_ostream &Out;
  29   std::vector<SectionHeader> SectionHeaders;
  30
  31   /// Generate a wasm section section header for S.
  32   /// The header consists of
  33   /// * A one-byte section ID (aka the section type).
  34   /// * The size of the section contents, encoded as ULEB128.
  35   /// * If the section is a custom section (type 0) it also has a name, which is
  36   ///   encoded as a length-prefixed string. The encoded section size *includes*
  37   ///   this string.
  38   /// See https://webassembly.github.io/spec/core/binary/modules.html#sections
  39   /// Return the header and store the total size in SectionSize.
  40   static SectionHeader createSectionHeader(const Section &S,
  41                                            size_t &SectionSize);
  42   size_t finalize();
  43 };
  44
  45 } // end namespace wasm
  46 } // end namespace objcopy
  47 } // end namespace llvm
  48
  49 #endif // LLVM_LIB_OBJCOPY_WASM_WASMWRITER_H