clang/utils/TableGen/ClangCommentHTMLNamedCharacterReferenceEmitter.cpp

   1 //===-- ClangCommentHTMLNamedCharacterReferenceEmitter.cpp ----------------===//
   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 // This tablegen backend emits an efficient function to translate HTML named
  10 // character references to UTF-8 sequences.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "TableGenBackends.h"
  15 #include "llvm/ADT/SmallString.h"
  16 #include "llvm/Support/ConvertUTF.h"
  17 #include "llvm/TableGen/Error.h"
  18 #include "llvm/TableGen/Record.h"
  19 #include "llvm/TableGen/StringMatcher.h"
  20 #include "llvm/TableGen/TableGenBackend.h"
  21 #include <vector>
  22
  23 using namespace llvm;
  24
  25 /// Convert a code point to the corresponding UTF-8 sequence represented
  26 /// as a C string literal.
  27 ///
  28 /// \returns true on success.
  29 static bool translateCodePointToUTF8(unsigned CodePoint,
  30                                      SmallVectorImpl<char> &CLiteral) {
  31   char Translated[UNI_MAX_UTF8_BYTES_PER_CODE_POINT];
  32   char *TranslatedPtr = Translated;
  33   if (!ConvertCodePointToUTF8(CodePoint, TranslatedPtr))
  34     return false;
  35
  36   StringRef UTF8(Translated, TranslatedPtr - Translated);
  37
  38   raw_svector_ostream OS(CLiteral);
  39   OS << "\"";
  40   for (size_t i = 0, e = UTF8.size(); i != e; ++i) {
  41     OS << "\\x";
  42     OS.write_hex(static_cast<unsigned char>(UTF8[i]));
  43   }
  44   OS << "\"";
  45
  46   return true;
  47 }
  48
  49 void clang::EmitClangCommentHTMLNamedCharacterReferences(
  50     const RecordKeeper &Records, raw_ostream &OS) {
  51   std::vector<StringMatcher::StringPair> NameToUTF8;
  52   SmallString<32> CLiteral;
  53   for (const Record *Tag : Records.getAllDerivedDefinitions("NCR")) {
  54     std::string Spelling = Tag->getValueAsString("Spelling").str();
  55     uint64_t CodePoint = Tag->getValueAsInt("CodePoint");
  56     CLiteral.clear();
  57     CLiteral.append("return ");
  58     if (!translateCodePointToUTF8(CodePoint, CLiteral)) {
  59       SrcMgr.PrintMessage(Tag->getLoc().front(), SourceMgr::DK_Error,
  60                           Twine("invalid code point"));
  61       continue;
  62     }
  63     CLiteral.append(";");
  64
  65     StringMatcher::StringPair Match(Spelling, std::string(CLiteral));
  66     NameToUTF8.push_back(Match);
  67   }
  68
  69   emitSourceFileHeader("HTML named character reference to UTF-8 translation",
  70                        OS, Records);
  71
  72   OS << "StringRef translateHTMLNamedCharacterReferenceToUTF8(\n"
  73         "                                             StringRef Name) {\n";
  74   StringMatcher("Name", NameToUTF8, OS).Emit();
  75   OS << "  return StringRef();\n"
  76      << "}\n\n";
  77 }