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ClangHighlighter.cpp
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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"
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 
22 using namespace lldb_private;
23 
24 bool ClangHighlighter::isKeyword(llvm::StringRef token) const {
25  return keywords.find(token) != keywords.end();
26 }
27 
29 #define KEYWORD(X, N) keywords.insert(#X);
30 #include "clang/Basic/TokenKinds.def"
31 }
32 
33 /// Determines which style should be applied to the given token.
34 /// \param highlighter
35 /// The current highlighter that should use the style.
36 /// \param token
37 /// The current token.
38 /// \param tok_str
39 /// The string in the source code the token represents.
40 /// \param options
41 /// The style we use for coloring the source code.
42 /// \param in_pp_directive
43 /// If we are currently in a preprocessor directive. NOTE: This is
44 /// passed by reference and will be updated if the current token starts
45 /// or ends a preprocessor directive.
46 /// \return
47 /// The ColorStyle that should be applied to the token.
50  const clang::Token &token, llvm::StringRef tok_str,
51  const HighlightStyle &options, bool &in_pp_directive) {
52  using namespace clang;
53 
54  if (token.is(tok::comment)) {
55  // If we were in a preprocessor directive before, we now left it.
56  in_pp_directive = false;
57  return options.comment;
58  } else if (in_pp_directive || token.getKind() == tok::hash) {
59  // Let's assume that the rest of the line is a PP directive.
60  in_pp_directive = true;
61  // Preprocessor directives are hard to match, so we have to hack this in.
62  return options.pp_directive;
63  } else if (tok::isStringLiteral(token.getKind()))
64  return options.string_literal;
65  else if (tok::isLiteral(token.getKind()))
66  return options.scalar_literal;
67  else if (highlighter.isKeyword(tok_str))
68  return options.keyword;
69  else
70  switch (token.getKind()) {
71  case tok::raw_identifier:
72  case tok::identifier:
73  return options.identifier;
74  case tok::l_brace:
75  case tok::r_brace:
76  return options.braces;
77  case tok::l_square:
78  case tok::r_square:
79  return options.square_brackets;
80  case tok::l_paren:
81  case tok::r_paren:
82  return options.parentheses;
83  case tok::comma:
84  return options.comma;
85  case tok::coloncolon:
86  case tok::colon:
87  return options.colon;
88 
89  case tok::amp:
90  case tok::ampamp:
91  case tok::ampequal:
92  case tok::star:
93  case tok::starequal:
94  case tok::plus:
95  case tok::plusplus:
96  case tok::plusequal:
97  case tok::minus:
98  case tok::arrow:
99  case tok::minusminus:
100  case tok::minusequal:
101  case tok::tilde:
102  case tok::exclaim:
103  case tok::exclaimequal:
104  case tok::slash:
105  case tok::slashequal:
106  case tok::percent:
107  case tok::percentequal:
108  case tok::less:
109  case tok::lessless:
110  case tok::lessequal:
111  case tok::lesslessequal:
112  case tok::spaceship:
113  case tok::greater:
114  case tok::greatergreater:
115  case tok::greaterequal:
116  case tok::greatergreaterequal:
117  case tok::caret:
118  case tok::caretequal:
119  case tok::pipe:
120  case tok::pipepipe:
121  case tok::pipeequal:
122  case tok::question:
123  case tok::equal:
124  case tok::equalequal:
125  return options.operators;
126  default:
127  break;
128  }
130 }
131 
133  llvm::StringRef line,
134  llvm::Optional<size_t> cursor_pos,
135  llvm::StringRef previous_lines,
136  Stream &result) const {
137  using namespace clang;
138 
139  FileSystemOptions file_opts;
140  FileManager file_mgr(file_opts,
141  FileSystem::Instance().GetVirtualFileSystem());
142 
143  // The line might end in a backslash which would cause Clang to drop the
144  // backslash and the terminating new line. This makes sense when parsing C++,
145  // but when highlighting we care about preserving the backslash/newline. To
146  // not lose this information we remove the new line here so that Clang knows
147  // this is just a single line we are highlighting. We add back the newline
148  // after tokenizing.
149  llvm::StringRef line_ending = "";
150  // There are a few legal line endings Clang recognizes and we need to
151  // temporarily remove from the string.
152  if (line.consume_back("\r\n"))
153  line_ending = "\r\n";
154  else if (line.consume_back("\n"))
155  line_ending = "\n";
156  else if (line.consume_back("\r"))
157  line_ending = "\r";
158 
159  unsigned line_number = previous_lines.count('\n') + 1U;
160 
161  // Let's build the actual source code Clang needs and setup some utility
162  // objects.
163  std::string full_source = previous_lines.str() + line.str();
164  llvm::IntrusiveRefCntPtr<DiagnosticIDs> diag_ids(new DiagnosticIDs());
165  llvm::IntrusiveRefCntPtr<DiagnosticOptions> diags_opts(
166  new DiagnosticOptions());
167  DiagnosticsEngine diags(diag_ids, diags_opts);
168  clang::SourceManager SM(diags, file_mgr);
169  auto buf = llvm::MemoryBuffer::getMemBuffer(full_source);
170 
171  FileID FID = SM.createFileID(clang::SourceManager::Unowned, buf.get());
172 
173  // Let's just enable the latest ObjC and C++ which should get most tokens
174  // right.
175  LangOptions Opts;
176  Opts.ObjC = true;
177  // FIXME: This should probably set CPlusPlus, CPlusPlus11, ... too
178  Opts.CPlusPlus17 = true;
179  Opts.LineComment = true;
180 
181  Lexer lex(FID, buf.get(), SM, Opts);
182  // The lexer should keep whitespace around.
183  lex.SetKeepWhitespaceMode(true);
184 
185  // Keeps track if we have entered a PP directive.
186  bool in_pp_directive = false;
187 
188  // True once we actually lexed the user provided line.
189  bool found_user_line = false;
190 
191  // True if we already highlighted the token under the cursor, false otherwise.
192  bool highlighted_cursor = false;
193  Token token;
194  bool exit = false;
195  while (!exit) {
196  // Returns true if this is the last token we get from the lexer.
197  exit = lex.LexFromRawLexer(token);
198 
199  bool invalid = false;
200  unsigned current_line_number =
201  SM.getSpellingLineNumber(token.getLocation(), &invalid);
202  if (current_line_number != line_number)
203  continue;
204  found_user_line = true;
205 
206  // We don't need to print any tokens without a spelling line number.
207  if (invalid)
208  continue;
209 
210  // Same as above but with the column number.
211  invalid = false;
212  unsigned start = SM.getSpellingColumnNumber(token.getLocation(), &invalid);
213  if (invalid)
214  continue;
215  // Column numbers start at 1, but indexes in our string start at 0.
216  --start;
217 
218  // Annotations don't have a length, so let's skip them.
219  if (token.isAnnotation())
220  continue;
221 
222  // Extract the token string from our source code.
223  llvm::StringRef tok_str = line.substr(start, token.getLength());
224 
225  // If the token is just an empty string, we can skip all the work below.
226  if (tok_str.empty())
227  continue;
228 
229  // If the cursor is inside this token, we have to apply the 'selected'
230  // highlight style before applying the actual token color.
231  llvm::StringRef to_print = tok_str;
232  StreamString storage;
233  auto end = start + token.getLength();
234  if (cursor_pos && end > *cursor_pos && !highlighted_cursor) {
235  highlighted_cursor = true;
236  options.selected.Apply(storage, tok_str);
237  to_print = storage.GetString();
238  }
239 
240  // See how we are supposed to highlight this token.
242  determineClangStyle(*this, token, tok_str, options, in_pp_directive);
243 
244  color.Apply(result, to_print);
245  }
246 
247  // Add the line ending we trimmed before tokenizing.
248  result << line_ending;
249 
250  // If we went over the whole file but couldn't find our own file, then
251  // somehow our setup was wrong. When we're in release mode we just give the
252  // user the normal line and pretend we don't know how to highlight it. In
253  // debug mode we bail out with an assert as this should never happen.
254  if (!found_user_line) {
255  result << line;
256  assert(false && "We couldn't find the user line in the input file?");
257  }
258 }
A class that represents a running process on the host machine.
A stream class that can stream formatted output to a file.
Definition: Stream.h:28
A pair of strings that should be placed around a certain token.
Definition: Highlighter.h:28
ColorStyle string_literal
Matches any string or character literals in the language: "foo" or &#39;f&#39;.
Definition: Highlighter.h:57
ColorStyle parentheses
Matches &#39;(&#39; or &#39;)&#39;.
Definition: Highlighter.h:78
ColorStyle operators
Matches operators like &#39;+&#39;, &#39;-&#39;, &#39;&#39;, &#39;&&#39;, &#39;=&#39;.
Definition: Highlighter.h:71
static FileSystem & Instance()
ColorStyle comma
Matches commas: &#39;,&#39;.
Definition: Highlighter.h:65
bool isKeyword(llvm::StringRef token) const
Returns true if the given string represents a keywords in any Clang supported language.
void Apply(Stream &s, llvm::StringRef value) const
Applies this style to the given value.
Definition: Highlighter.cpp:18
llvm::StringRef GetString() const
ColorStyle square_brackets
Matches &#39;[&#39; or &#39;]&#39;.
Definition: Highlighter.h:76
ColorStyle selected
The style for the token which is below the cursor of the user.
Definition: Highlighter.h:52
ColorStyle keyword
Matches all reserved keywords in the language.
Definition: Highlighter.h:61
Represents style that the highlighter should apply to the given source code.
Definition: Highlighter.h:23
ColorStyle pp_directive
Matches directives to a preprocessor (if the language has any).
Definition: Highlighter.h:83
ColorStyle identifier
Matches identifiers to variable or functions.
Definition: Highlighter.h:55
ColorStyle colon
Matches one colon: &#39;:&#39;.
Definition: Highlighter.h:67
ColorStyle comment
Matches any comments in the language.
Definition: Highlighter.h:63
ColorStyle braces
Matches &#39;{&#39; or &#39;}&#39;.
Definition: Highlighter.h:74
void Highlight(const HighlightStyle &options, llvm::StringRef line, llvm::Optional< size_t > cursor_pos, llvm::StringRef previous_lines, Stream &s) const override
Highlights the given line.
static HighlightStyle::ColorStyle determineClangStyle(const ClangHighlighter &highlighter, const clang::Token &token, llvm::StringRef tok_str, const HighlightStyle &options, bool &in_pp_directive)
Determines which style should be applied to the given token.
ColorStyle scalar_literal
Matches scalar value literals like &#39;42&#39; or &#39;0.1&#39;.
Definition: Highlighter.h:59