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
23using 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.
29static 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(Source: CodePoint, ResultPtr&: TranslatedPtr))
34 return false;
35
36 StringRef UTF8(Translated, TranslatedPtr - Translated);
37
38 raw_svector_ostream OS(CLiteral);
39 OS << "\"";
40 for (char C : UTF8) {
41 OS << "\\x";
42 OS.write_hex(N: static_cast<unsigned char>(C));
43 }
44 OS << "\"";
45
46 return true;
47}
48
49void 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(ClassName: "NCR")) {
54 std::string Spelling = Tag->getValueAsString(FieldName: "Spelling").str();
55 uint64_t CodePoint = Tag->getValueAsInt(FieldName: "CodePoint");
56 CLiteral.clear();
57 CLiteral.append(RHS: "return ");
58 if (!translateCodePointToUTF8(CodePoint, CLiteral)) {
59 SrcMgr.PrintMessage(Loc: Tag->getLoc().front(), Kind: SourceMgr::DK_Error,
60 Msg: Twine("invalid code point"));
61 continue;
62 }
63 CLiteral.append(RHS: ";");
64
65 StringMatcher::StringPair Match(Spelling, std::string(CLiteral));
66 NameToUTF8.push_back(x: Match);
67 }
68
69 emitSourceFileHeader(Desc: "HTML named character reference to UTF-8 translation",
70 OS, Record: 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}
78