clang-tools  11.0.0
ArgumentCommentCheck.cpp
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1 //===--- ArgumentCommentCheck.cpp - clang-tidy ----------------------------===//
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 "ArgumentCommentCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Lex/Lexer.h"
13 #include "clang/Lex/Token.h"
14 
15 #include "../utils/LexerUtils.h"
16 
17 using namespace clang::ast_matchers;
18 
19 namespace clang {
20 namespace tidy {
21 namespace bugprone {
22 namespace {
23 AST_MATCHER(Decl, isFromStdNamespace) {
24  if (const auto *D = Node.getDeclContext()->getEnclosingNamespaceContext())
25  return D->isStdNamespace();
26  return false;
27 }
28 } // namespace
29 
30 ArgumentCommentCheck::ArgumentCommentCheck(StringRef Name,
31  ClangTidyContext *Context)
32  : ClangTidyCheck(Name, Context),
33  StrictMode(Options.getLocalOrGlobal("StrictMode", false)),
34  IgnoreSingleArgument(Options.get("IgnoreSingleArgument", false)),
35  CommentBoolLiterals(Options.get("CommentBoolLiterals", false)),
36  CommentIntegerLiterals(Options.get("CommentIntegerLiterals", false)),
37  CommentFloatLiterals(Options.get("CommentFloatLiterals", false)),
38  CommentStringLiterals(Options.get("CommentStringLiterals", false)),
39  CommentUserDefinedLiterals(
40  Options.get("CommentUserDefinedLiterals", false)),
41  CommentCharacterLiterals(Options.get("CommentCharacterLiterals", false)),
42  CommentNullPtrs(Options.get("CommentNullPtrs", false)),
43  IdentRE("^(/\\* *)([_A-Za-z][_A-Za-z0-9]*)( *= *\\*/)$") {}
44 
46  Options.store(Opts, "StrictMode", StrictMode);
47  Options.store(Opts, "IgnoreSingleArgument", IgnoreSingleArgument);
48  Options.store(Opts, "CommentBoolLiterals", CommentBoolLiterals);
49  Options.store(Opts, "CommentIntegerLiterals", CommentIntegerLiterals);
50  Options.store(Opts, "CommentFloatLiterals", CommentFloatLiterals);
51  Options.store(Opts, "CommentStringLiterals", CommentStringLiterals);
52  Options.store(Opts, "CommentUserDefinedLiterals", CommentUserDefinedLiterals);
53  Options.store(Opts, "CommentCharacterLiterals", CommentCharacterLiterals);
54  Options.store(Opts, "CommentNullPtrs", CommentNullPtrs);
55 }
56 
57 void ArgumentCommentCheck::registerMatchers(MatchFinder *Finder) {
58  Finder->addMatcher(
59  callExpr(unless(cxxOperatorCallExpr()),
60  // NewCallback's arguments relate to the pointed function,
61  // don't check them against NewCallback's parameter names.
62  // FIXME: Make this configurable.
63  unless(hasDeclaration(functionDecl(
64  hasAnyName("NewCallback", "NewPermanentCallback")))),
65  // Ignore APIs from the standard library, since their names are
66  // not specified by the standard, and standard library
67  // implementations in practice have to use reserved names to
68  // avoid conflicts with same-named macros.
69  unless(hasDeclaration(isFromStdNamespace())))
70  .bind("expr"),
71  this);
72  Finder->addMatcher(
73  cxxConstructExpr(unless(hasDeclaration(isFromStdNamespace())))
74  .bind("expr"),
75  this);
76 }
77 
78 static std::vector<std::pair<SourceLocation, StringRef>>
79 getCommentsInRange(ASTContext *Ctx, CharSourceRange Range) {
80  std::vector<std::pair<SourceLocation, StringRef>> Comments;
81  auto &SM = Ctx->getSourceManager();
82  std::pair<FileID, unsigned> BeginLoc = SM.getDecomposedLoc(Range.getBegin()),
83  EndLoc = SM.getDecomposedLoc(Range.getEnd());
84 
85  if (BeginLoc.first != EndLoc.first)
86  return Comments;
87 
88  bool Invalid = false;
89  StringRef Buffer = SM.getBufferData(BeginLoc.first, &Invalid);
90  if (Invalid)
91  return Comments;
92 
93  const char *StrData = Buffer.data() + BeginLoc.second;
94 
95  Lexer TheLexer(SM.getLocForStartOfFile(BeginLoc.first), Ctx->getLangOpts(),
96  Buffer.begin(), StrData, Buffer.end());
97  TheLexer.SetCommentRetentionState(true);
98 
99  while (true) {
100  Token Tok;
101  if (TheLexer.LexFromRawLexer(Tok))
102  break;
103  if (Tok.getLocation() == Range.getEnd() || Tok.is(tok::eof))
104  break;
105 
106  if (Tok.is(tok::comment)) {
107  std::pair<FileID, unsigned> CommentLoc =
108  SM.getDecomposedLoc(Tok.getLocation());
109  assert(CommentLoc.first == BeginLoc.first);
110  Comments.emplace_back(
111  Tok.getLocation(),
112  StringRef(Buffer.begin() + CommentLoc.second, Tok.getLength()));
113  } else {
114  // Clear comments found before the different token, e.g. comma.
115  Comments.clear();
116  }
117  }
118 
119  return Comments;
120 }
121 
122 static std::vector<std::pair<SourceLocation, StringRef>>
123 getCommentsBeforeLoc(ASTContext *Ctx, SourceLocation Loc) {
124  std::vector<std::pair<SourceLocation, StringRef>> Comments;
125  while (Loc.isValid()) {
126  clang::Token Tok = utils::lexer::getPreviousToken(
127  Loc, Ctx->getSourceManager(), Ctx->getLangOpts(),
128  /*SkipComments=*/false);
129  if (Tok.isNot(tok::comment))
130  break;
131  Loc = Tok.getLocation();
132  Comments.emplace_back(
133  Loc,
134  Lexer::getSourceText(CharSourceRange::getCharRange(
135  Loc, Loc.getLocWithOffset(Tok.getLength())),
136  Ctx->getSourceManager(), Ctx->getLangOpts()));
137  }
138  return Comments;
139 }
140 
141 static bool isLikelyTypo(llvm::ArrayRef<ParmVarDecl *> Params,
142  StringRef ArgName, unsigned ArgIndex) {
143  std::string ArgNameLowerStr = ArgName.lower();
144  StringRef ArgNameLower = ArgNameLowerStr;
145  // The threshold is arbitrary.
146  unsigned UpperBound = (ArgName.size() + 2) / 3 + 1;
147  unsigned ThisED = ArgNameLower.edit_distance(
148  Params[ArgIndex]->getIdentifier()->getName().lower(),
149  /*AllowReplacements=*/true, UpperBound);
150  if (ThisED >= UpperBound)
151  return false;
152 
153  for (unsigned I = 0, E = Params.size(); I != E; ++I) {
154  if (I == ArgIndex)
155  continue;
156  IdentifierInfo *II = Params[I]->getIdentifier();
157  if (!II)
158  continue;
159 
160  const unsigned Threshold = 2;
161  // Other parameters must be an edit distance at least Threshold more away
162  // from this parameter. This gives us greater confidence that this is a
163  // typo of this parameter and not one with a similar name.
164  unsigned OtherED = ArgNameLower.edit_distance(II->getName().lower(),
165  /*AllowReplacements=*/true,
166  ThisED + Threshold);
167  if (OtherED < ThisED + Threshold)
168  return false;
169  }
170 
171  return true;
172 }
173 
174 static bool sameName(StringRef InComment, StringRef InDecl, bool StrictMode) {
175  if (StrictMode)
176  return InComment == InDecl;
177  InComment = InComment.trim('_');
178  InDecl = InDecl.trim('_');
179  // FIXME: compare_lower only works for ASCII.
180  return InComment.compare_lower(InDecl) == 0;
181 }
182 
183 static bool looksLikeExpectMethod(const CXXMethodDecl *Expect) {
184  return Expect != nullptr && Expect->getLocation().isMacroID() &&
185  Expect->getNameInfo().getName().isIdentifier() &&
186  Expect->getName().startswith("gmock_");
187 }
188 static bool areMockAndExpectMethods(const CXXMethodDecl *Mock,
189  const CXXMethodDecl *Expect) {
190  assert(looksLikeExpectMethod(Expect));
191  return Mock != nullptr && Mock->getNextDeclInContext() == Expect &&
192  Mock->getNumParams() == Expect->getNumParams() &&
193  Mock->getLocation().isMacroID() &&
194  Mock->getNameInfo().getName().isIdentifier() &&
195  Mock->getName() == Expect->getName().substr(strlen("gmock_"));
196 }
197 
198 // This uses implementation details of MOCK_METHODx_ macros: for each mocked
199 // method M it defines M() with appropriate signature and a method used to set
200 // up expectations - gmock_M() - with each argument's type changed the
201 // corresponding matcher. This function returns M when given either M or
202 // gmock_M.
203 static const CXXMethodDecl *findMockedMethod(const CXXMethodDecl *Method) {
204  if (looksLikeExpectMethod(Method)) {
205  const DeclContext *Ctx = Method->getDeclContext();
206  if (Ctx == nullptr || !Ctx->isRecord())
207  return nullptr;
208  for (const auto *D : Ctx->decls()) {
209  if (D->getNextDeclInContext() == Method) {
210  const auto *Previous = dyn_cast<CXXMethodDecl>(D);
211  return areMockAndExpectMethods(Previous, Method) ? Previous : nullptr;
212  }
213  }
214  return nullptr;
215  }
216  if (const auto *Next =
217  dyn_cast_or_null<CXXMethodDecl>(Method->getNextDeclInContext())) {
218  if (looksLikeExpectMethod(Next) && areMockAndExpectMethods(Method, Next))
219  return Method;
220  }
221  return nullptr;
222 }
223 
224 // For gmock expectation builder method (the target of the call generated by
225 // `EXPECT_CALL(obj, Method(...))`) tries to find the real method being mocked
226 // (returns nullptr, if the mock method doesn't override anything). For other
227 // functions returns the function itself.
228 static const FunctionDecl *resolveMocks(const FunctionDecl *Func) {
229  if (const auto *Method = dyn_cast<CXXMethodDecl>(Func)) {
230  if (const auto *MockedMethod = findMockedMethod(Method)) {
231  // If mocked method overrides the real one, we can use its parameter
232  // names, otherwise we're out of luck.
233  if (MockedMethod->size_overridden_methods() > 0) {
234  return *MockedMethod->begin_overridden_methods();
235  }
236  return nullptr;
237  }
238  }
239  return Func;
240 }
241 
242 // Given the argument type and the options determine if we should
243 // be adding an argument comment.
244 bool ArgumentCommentCheck::shouldAddComment(const Expr *Arg) const {
245  Arg = Arg->IgnoreImpCasts();
246  if (isa<UnaryOperator>(Arg))
247  Arg = cast<UnaryOperator>(Arg)->getSubExpr();
248  if (Arg->getExprLoc().isMacroID())
249  return false;
250  return (CommentBoolLiterals && isa<CXXBoolLiteralExpr>(Arg)) ||
251  (CommentIntegerLiterals && isa<IntegerLiteral>(Arg)) ||
252  (CommentFloatLiterals && isa<FloatingLiteral>(Arg)) ||
253  (CommentUserDefinedLiterals && isa<UserDefinedLiteral>(Arg)) ||
254  (CommentCharacterLiterals && isa<CharacterLiteral>(Arg)) ||
255  (CommentStringLiterals && isa<StringLiteral>(Arg)) ||
256  (CommentNullPtrs && isa<CXXNullPtrLiteralExpr>(Arg));
257 }
258 
259 void ArgumentCommentCheck::checkCallArgs(ASTContext *Ctx,
260  const FunctionDecl *OriginalCallee,
261  SourceLocation ArgBeginLoc,
262  llvm::ArrayRef<const Expr *> Args) {
263  const FunctionDecl *Callee = resolveMocks(OriginalCallee);
264  if (!Callee)
265  return;
266 
267  Callee = Callee->getFirstDecl();
268  unsigned NumArgs = std::min<unsigned>(Args.size(), Callee->getNumParams());
269  if ((NumArgs == 0) || (IgnoreSingleArgument && NumArgs == 1))
270  return;
271 
272  auto MakeFileCharRange = [Ctx](SourceLocation Begin, SourceLocation End) {
273  return Lexer::makeFileCharRange(CharSourceRange::getCharRange(Begin, End),
274  Ctx->getSourceManager(),
275  Ctx->getLangOpts());
276  };
277 
278  for (unsigned I = 0; I < NumArgs; ++I) {
279  const ParmVarDecl *PVD = Callee->getParamDecl(I);
280  IdentifierInfo *II = PVD->getIdentifier();
281  if (!II)
282  continue;
283  if (auto Template = Callee->getTemplateInstantiationPattern()) {
284  // Don't warn on arguments for parameters instantiated from template
285  // parameter packs. If we find more arguments than the template
286  // definition has, it also means that they correspond to a parameter
287  // pack.
288  if (Template->getNumParams() <= I ||
289  Template->getParamDecl(I)->isParameterPack()) {
290  continue;
291  }
292  }
293 
294  CharSourceRange BeforeArgument =
295  MakeFileCharRange(ArgBeginLoc, Args[I]->getBeginLoc());
296  ArgBeginLoc = Args[I]->getEndLoc();
297 
298  std::vector<std::pair<SourceLocation, StringRef>> Comments;
299  if (BeforeArgument.isValid()) {
300  Comments = getCommentsInRange(Ctx, BeforeArgument);
301  } else {
302  // Fall back to parsing back from the start of the argument.
303  CharSourceRange ArgsRange =
304  MakeFileCharRange(Args[I]->getBeginLoc(), Args[I]->getEndLoc());
305  Comments = getCommentsBeforeLoc(Ctx, ArgsRange.getBegin());
306  }
307 
308  for (auto Comment : Comments) {
309  llvm::SmallVector<StringRef, 2> Matches;
310  if (IdentRE.match(Comment.second, &Matches) &&
311  !sameName(Matches[2], II->getName(), StrictMode)) {
312  {
313  DiagnosticBuilder Diag =
314  diag(Comment.first, "argument name '%0' in comment does not "
315  "match parameter name %1")
316  << Matches[2] << II;
317  if (isLikelyTypo(Callee->parameters(), Matches[2], I)) {
318  Diag << FixItHint::CreateReplacement(
319  Comment.first, (Matches[1] + II->getName() + Matches[3]).str());
320  }
321  }
322  diag(PVD->getLocation(), "%0 declared here", DiagnosticIDs::Note) << II;
323  if (OriginalCallee != Callee) {
324  diag(OriginalCallee->getLocation(),
325  "actual callee (%0) is declared here", DiagnosticIDs::Note)
326  << OriginalCallee;
327  }
328  }
329  }
330 
331  // If the argument comments are missing for literals add them.
332  if (Comments.empty() && shouldAddComment(Args[I])) {
333  std::string ArgComment =
334  (llvm::Twine("/*") + II->getName() + "=*/").str();
335  DiagnosticBuilder Diag =
336  diag(Args[I]->getBeginLoc(),
337  "argument comment missing for literal argument %0")
338  << II
339  << FixItHint::CreateInsertion(Args[I]->getBeginLoc(), ArgComment);
340  }
341  }
342 }
343 
344 void ArgumentCommentCheck::check(const MatchFinder::MatchResult &Result) {
345  const auto *E = Result.Nodes.getNodeAs<Expr>("expr");
346  if (const auto *Call = dyn_cast<CallExpr>(E)) {
347  const FunctionDecl *Callee = Call->getDirectCallee();
348  if (!Callee)
349  return;
350 
351  checkCallArgs(Result.Context, Callee, Call->getCallee()->getEndLoc(),
352  llvm::makeArrayRef(Call->getArgs(), Call->getNumArgs()));
353  } else {
354  const auto *Construct = cast<CXXConstructExpr>(E);
355  if (Construct->getNumArgs() > 0 &&
356  Construct->getArg(0)->getSourceRange() == Construct->getSourceRange()) {
357  // Ignore implicit construction.
358  return;
359  }
360  checkCallArgs(
361  Result.Context, Construct->getConstructor(),
362  Construct->getParenOrBraceRange().getBegin(),
363  llvm::makeArrayRef(Construct->getArgs(), Construct->getNumArgs()));
364  }
365 }
366 
367 } // namespace bugprone
368 } // namespace tidy
369 } // namespace clang
clang::tidy::bugprone::resolveMocks
static const FunctionDecl * resolveMocks(const FunctionDecl *Func)
Definition: ArgumentCommentCheck.cpp:228
Range
CharSourceRange Range
SourceRange for the file name.
Definition: IncludeOrderCheck.cpp:38
clang::tidy::bugprone::ArgumentCommentCheck::check
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Definition: ArgumentCommentCheck.cpp:344
E
const Expr * E
Definition: AvoidBindCheck.cpp:88
clang::tidy::bugprone::looksLikeExpectMethod
static bool looksLikeExpectMethod(const CXXMethodDecl *Expect)
Definition: ArgumentCommentCheck.cpp:183
clang::tidy::bugprone::getCommentsBeforeLoc
static std::vector< std::pair< SourceLocation, StringRef > > getCommentsBeforeLoc(ASTContext *Ctx, SourceLocation Loc)
Definition: ArgumentCommentCheck.cpp:123
clang::tidy::bugprone::areMockAndExpectMethods
static bool areMockAndExpectMethods(const CXXMethodDecl *Mock, const CXXMethodDecl *Expect)
Definition: ArgumentCommentCheck.cpp:188
clang::tidy::bugprone::ArgumentCommentCheck::storeOptions
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
Definition: ArgumentCommentCheck.cpp:45
Ctx
Context Ctx
Definition: TUScheduler.cpp:324
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidyCheck.h:114
clang::clangd::lower
static char lower(char C)
Definition: FuzzyMatch.cpp:68
clang::tidy::bugprone::getCommentsInRange
static std::vector< std::pair< SourceLocation, StringRef > > getCommentsInRange(ASTContext *Ctx, CharSourceRange Range)
Definition: ArgumentCommentCheck.cpp:79
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::tidy::utils::lexer::getPreviousToken
Token getPreviousToken(SourceLocation Location, const SourceManager &SM, const LangOptions &LangOpts, bool SkipComments)
Returns previous token or tok::unknown if not found.
Definition: LexerUtils.cpp:17
Decl
const FunctionDecl * Decl
Definition: AvoidBindCheck.cpp:100
clang::tidy::bugprone::ArgumentCommentCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Definition: ArgumentCommentCheck.cpp:57
clang::tidy::ClangTidyCheck::Options
OptionsView Options
Definition: ClangTidyCheck.h:471
ArgumentCommentCheck.h
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:76
Name
static constexpr llvm::StringLiteral Name
Definition: UppercaseLiteralSuffixCheck.cpp:27
clang::tidy::ClangTidyCheck::diag
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
Definition: ClangTidyCheck.cpp:55
clang::ast_matchers::AST_MATCHER
AST_MATCHER(Expr, isMacroID)
Definition: PreferIsaOrDynCastInConditionalsCheck.cpp:19
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
clang::tidy::bugprone::findMockedMethod
static const CXXMethodDecl * findMockedMethod(const CXXMethodDecl *Method)
Definition: ArgumentCommentCheck.cpp:203
clang::tidy::bugprone::isLikelyTypo
static bool isLikelyTypo(llvm::ArrayRef< ParmVarDecl * > Params, StringRef ArgName, unsigned ArgIndex)
Definition: ArgumentCommentCheck.cpp:141
clang::tidy::ClangTidyCheck::OptionsView::store
void store(ClangTidyOptions::OptionMap &Options, StringRef LocalName, StringRef Value) const
Stores an option with the check-local name LocalName with string value Value to Options.
Definition: ClangTidyCheck.cpp:152
Loc
SourceLocation Loc
'#' location in the include directive
Definition: IncludeOrderCheck.cpp:37
clang::tidy::bugprone::sameName
static bool sameName(StringRef InComment, StringRef InDecl, bool StrictMode)
Definition: ArgumentCommentCheck.cpp:174
clang::tidy::ClangTidyOptions::OptionMap
std::map< std::string, ClangTidyValue > OptionMap
Definition: ClangTidyOptions.h:111