llvm-project/llvm/lib/TableGen/TableGenBackend.cpp

//===- TableGenBackend.cpp - Utilities for TableGen Backends ----*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file provides useful services for TableGen backends...
//
//===----------------------------------------------------------------------===//

#include "llvm/TableGen/TableGenBackend.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/raw_ostream.h"

using namespace llvm;

const size_t MAX_LINE_LEN = 80U;

static void printLine(raw_ostream &OS, const Twine &Prefix, char Fill,
                      StringRef Suffix) {
  size_t Pos = (size_t)OS.tell();
  assert((Prefix.str().size() + Suffix.size() <= MAX_LINE_LEN) &&
         "header line exceeds max limit");
  OS << Prefix;
  for (size_t i = (size_t)OS.tell() - Pos, e = MAX_LINE_LEN - Suffix.size();
         i < e; ++i)
    OS << Fill;
  OS << Suffix << '\n';
}

void llvm::emitSourceFileHeader(StringRef Desc, raw_ostream &OS) {
  printLine(OS, "/*===- TableGen'erated file ", '-', "*- C++ -*-===*\\");
  StringRef Prefix("|* ");
  StringRef Suffix(" *|");
  printLine(OS, Prefix, ' ', Suffix);
  size_t PSLen = Prefix.size() + Suffix.size();
  assert(PSLen < MAX_LINE_LEN);
  size_t Pos = 0U;
  do {
    size_t Length = std::min(Desc.size() - Pos, MAX_LINE_LEN - PSLen);
    printLine(OS, Prefix + Desc.substr(Pos, Length), ' ', Suffix);
    Pos += Length;
  } while (Pos < Desc.size());
  printLine(OS, Prefix, ' ', Suffix);
  printLine(OS, Prefix + "Automatically generated file, do not edit!", ' ',
    Suffix);
  printLine(OS, Prefix, ' ', Suffix);
  printLine(OS, "\\*===", '-', "===*/");
  OS << '\n';
}