1 //===-- ClangHighlighter.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 #include "ClangHighlighter.h"
10
11 #include "lldb/Host/FileSystem.h"
12 #include "lldb/Target/Language.h"
13 #include "lldb/Utility/AnsiTerminal.h"
14 #include "lldb/Utility/StreamString.h"
15
16 #include "clang/Basic/FileManager.h"
17 #include "clang/Basic/SourceManager.h"
18 #include "clang/Lex/Lexer.h"
19 #include "llvm/ADT/StringSet.h"
20 #include "llvm/Support/MemoryBuffer.h"
21 #include <optional>
22
23 using namespace lldb_private;
24
isKeyword(llvm::StringRef token) const25 bool ClangHighlighter::isKeyword(llvm::StringRef token) const {
26 return keywords.contains(token);
27 }
28
ClangHighlighter()29 ClangHighlighter::ClangHighlighter() {
30 #define KEYWORD(X, N) keywords.insert(#X);
31 #include "clang/Basic/TokenKinds.def"
32 }
33
34 /// Determines which style should be applied to the given token.
35 /// \param highlighter
36 /// The current highlighter that should use the style.
37 /// \param token
38 /// The current token.
39 /// \param tok_str
40 /// The string in the source code the token represents.
41 /// \param options
42 /// The style we use for coloring the source code.
43 /// \param in_pp_directive
44 /// If we are currently in a preprocessor directive. NOTE: This is
45 /// passed by reference and will be updated if the current token starts
46 /// or ends a preprocessor directive.
47 /// \return
48 /// The ColorStyle that should be applied to the token.
49 static HighlightStyle::ColorStyle
determineClangStyle(const ClangHighlighter & highlighter,const clang::Token & token,llvm::StringRef tok_str,const HighlightStyle & options,bool & in_pp_directive)50 determineClangStyle(const ClangHighlighter &highlighter,
51 const clang::Token &token, llvm::StringRef tok_str,
52 const HighlightStyle &options, bool &in_pp_directive) {
53 using namespace clang;
54
55 if (token.is(tok::comment)) {
56 // If we were in a preprocessor directive before, we now left it.
57 in_pp_directive = false;
58 return options.comment;
59 } else if (in_pp_directive || token.getKind() == tok::hash) {
60 // Let's assume that the rest of the line is a PP directive.
61 in_pp_directive = true;
62 // Preprocessor directives are hard to match, so we have to hack this in.
63 return options.pp_directive;
64 } else if (tok::isStringLiteral(token.getKind()))
65 return options.string_literal;
66 else if (tok::isLiteral(token.getKind()))
67 return options.scalar_literal;
68 else if (highlighter.isKeyword(tok_str))
69 return options.keyword;
70 else
71 switch (token.getKind()) {
72 case tok::raw_identifier:
73 case tok::identifier:
74 return options.identifier;
75 case tok::l_brace:
76 case tok::r_brace:
77 return options.braces;
78 case tok::l_square:
79 case tok::r_square:
80 return options.square_brackets;
81 case tok::l_paren:
82 case tok::r_paren:
83 return options.parentheses;
84 case tok::comma:
85 return options.comma;
86 case tok::coloncolon:
87 case tok::colon:
88 return options.colon;
89
90 case tok::amp:
91 case tok::ampamp:
92 case tok::ampequal:
93 case tok::star:
94 case tok::starequal:
95 case tok::plus:
96 case tok::plusplus:
97 case tok::plusequal:
98 case tok::minus:
99 case tok::arrow:
100 case tok::minusminus:
101 case tok::minusequal:
102 case tok::tilde:
103 case tok::exclaim:
104 case tok::exclaimequal:
105 case tok::slash:
106 case tok::slashequal:
107 case tok::percent:
108 case tok::percentequal:
109 case tok::less:
110 case tok::lessless:
111 case tok::lessequal:
112 case tok::lesslessequal:
113 case tok::spaceship:
114 case tok::greater:
115 case tok::greatergreater:
116 case tok::greaterequal:
117 case tok::greatergreaterequal:
118 case tok::caret:
119 case tok::caretequal:
120 case tok::pipe:
121 case tok::pipepipe:
122 case tok::pipeequal:
123 case tok::question:
124 case tok::equal:
125 case tok::equalequal:
126 return options.operators;
127 default:
128 break;
129 }
130 return HighlightStyle::ColorStyle();
131 }
132
Highlight(const HighlightStyle & options,llvm::StringRef line,std::optional<size_t> cursor_pos,llvm::StringRef previous_lines,Stream & result) const133 void ClangHighlighter::Highlight(const HighlightStyle &options,
134 llvm::StringRef line,
135 std::optional<size_t> cursor_pos,
136 llvm::StringRef previous_lines,
137 Stream &result) const {
138 using namespace clang;
139
140 FileSystemOptions file_opts;
141 FileManager file_mgr(file_opts,
142 FileSystem::Instance().GetVirtualFileSystem());
143
144 // The line might end in a backslash which would cause Clang to drop the
145 // backslash and the terminating new line. This makes sense when parsing C++,
146 // but when highlighting we care about preserving the backslash/newline. To
147 // not lose this information we remove the new line here so that Clang knows
148 // this is just a single line we are highlighting. We add back the newline
149 // after tokenizing.
150 llvm::StringRef line_ending = "";
151 // There are a few legal line endings Clang recognizes and we need to
152 // temporarily remove from the string.
153 if (line.consume_back("\r\n"))
154 line_ending = "\r\n";
155 else if (line.consume_back("\n"))
156 line_ending = "\n";
157 else if (line.consume_back("\r"))
158 line_ending = "\r";
159
160 unsigned line_number = previous_lines.count('\n') + 1U;
161
162 // Let's build the actual source code Clang needs and setup some utility
163 // objects.
164 std::string full_source = previous_lines.str() + line.str();
165 llvm::IntrusiveRefCntPtr<DiagnosticIDs> diag_ids(new DiagnosticIDs());
166 llvm::IntrusiveRefCntPtr<DiagnosticOptions> diags_opts(
167 new DiagnosticOptions());
168 DiagnosticsEngine diags(diag_ids, diags_opts);
169 clang::SourceManager SM(diags, file_mgr);
170 auto buf = llvm::MemoryBuffer::getMemBuffer(full_source);
171
172 FileID FID = SM.createFileID(buf->getMemBufferRef());
173
174 // Let's just enable the latest ObjC and C++ which should get most tokens
175 // right.
176 LangOptions Opts;
177 Opts.ObjC = true;
178 // FIXME: This should probably set CPlusPlus, CPlusPlus11, ... too
179 Opts.CPlusPlus17 = true;
180 Opts.LineComment = true;
181
182 Lexer lex(FID, buf->getMemBufferRef(), SM, Opts);
183 // The lexer should keep whitespace around.
184 lex.SetKeepWhitespaceMode(true);
185
186 // Keeps track if we have entered a PP directive.
187 bool in_pp_directive = false;
188
189 // True once we actually lexed the user provided line.
190 bool found_user_line = false;
191
192 // True if we already highlighted the token under the cursor, false otherwise.
193 bool highlighted_cursor = false;
194 Token token;
195 bool exit = false;
196 while (!exit) {
197 // Returns true if this is the last token we get from the lexer.
198 exit = lex.LexFromRawLexer(token);
199
200 bool invalid = false;
201 unsigned current_line_number =
202 SM.getSpellingLineNumber(token.getLocation(), &invalid);
203 if (current_line_number != line_number)
204 continue;
205 found_user_line = true;
206
207 // We don't need to print any tokens without a spelling line number.
208 if (invalid)
209 continue;
210
211 // Same as above but with the column number.
212 invalid = false;
213 unsigned start = SM.getSpellingColumnNumber(token.getLocation(), &invalid);
214 if (invalid)
215 continue;
216 // Column numbers start at 1, but indexes in our string start at 0.
217 --start;
218
219 // Annotations don't have a length, so let's skip them.
220 if (token.isAnnotation())
221 continue;
222
223 // Extract the token string from our source code.
224 llvm::StringRef tok_str = line.substr(start, token.getLength());
225
226 // If the token is just an empty string, we can skip all the work below.
227 if (tok_str.empty())
228 continue;
229
230 // If the cursor is inside this token, we have to apply the 'selected'
231 // highlight style before applying the actual token color.
232 llvm::StringRef to_print = tok_str;
233 StreamString storage;
234 auto end = start + token.getLength();
235 if (cursor_pos && end > *cursor_pos && !highlighted_cursor) {
236 highlighted_cursor = true;
237 options.selected.Apply(storage, tok_str);
238 to_print = storage.GetString();
239 }
240
241 // See how we are supposed to highlight this token.
242 HighlightStyle::ColorStyle color =
243 determineClangStyle(*this, token, tok_str, options, in_pp_directive);
244
245 color.Apply(result, to_print);
246 }
247
248 // Add the line ending we trimmed before tokenizing.
249 result << line_ending;
250
251 // If we went over the whole file but couldn't find our own file, then
252 // somehow our setup was wrong. When we're in release mode we just give the
253 // user the normal line and pretend we don't know how to highlight it. In
254 // debug mode we bail out with an assert as this should never happen.
255 if (!found_user_line) {
256 result << line;
257 assert(false && "We couldn't find the user line in the input file?");
258 }
259 }
260