clang-tools  9.0.0
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 
23 ArgumentCommentCheck::ArgumentCommentCheck(StringRef Name,
24  ClangTidyContext *Context)
25  : ClangTidyCheck(Name, Context),
26  StrictMode(Options.getLocalOrGlobal("StrictMode", 0) != 0),
27  CommentBoolLiterals(Options.getLocalOrGlobal("CommentBoolLiterals", 0) !=
28  0),
29  CommentIntegerLiterals(
30  Options.getLocalOrGlobal("CommentIntegerLiterals", 0) != 0),
31  CommentFloatLiterals(
32  Options.getLocalOrGlobal("CommentFloatLiterals", 0) != 0),
33  CommentStringLiterals(
34  Options.getLocalOrGlobal("CommentStringLiterals", 0) != 0),
35  CommentUserDefinedLiterals(
36  Options.getLocalOrGlobal("CommentUserDefinedLiterals", 0) != 0),
37  CommentCharacterLiterals(
38  Options.getLocalOrGlobal("CommentCharacterLiterals", 0) != 0),
39  CommentNullPtrs(Options.getLocalOrGlobal("CommentNullPtrs", 0) != 0),
40  IdentRE("^(/\\* *)([_A-Za-z][_A-Za-z0-9]*)( *= *\\*/)$") {}
41 
43  Options.store(Opts, "StrictMode", StrictMode);
44  Options.store(Opts, "CommentBoolLiterals", CommentBoolLiterals);
45  Options.store(Opts, "CommentIntegerLiterals", CommentIntegerLiterals);
46  Options.store(Opts, "CommentFloatLiterals", CommentFloatLiterals);
47  Options.store(Opts, "CommentStringLiterals", CommentStringLiterals);
48  Options.store(Opts, "CommentUserDefinedLiterals", CommentUserDefinedLiterals);
49  Options.store(Opts, "CommentCharacterLiterals", CommentCharacterLiterals);
50  Options.store(Opts, "CommentNullPtrs", CommentNullPtrs);
51 }
52 
53 void ArgumentCommentCheck::registerMatchers(MatchFinder *Finder) {
54  Finder->addMatcher(
55  callExpr(unless(cxxOperatorCallExpr()),
56  // NewCallback's arguments relate to the pointed function,
57  // don't check them against NewCallback's parameter names.
58  // FIXME: Make this configurable.
59  unless(hasDeclaration(functionDecl(
60  hasAnyName("NewCallback", "NewPermanentCallback")))))
61  .bind("expr"),
62  this);
63  Finder->addMatcher(cxxConstructExpr().bind("expr"), this);
64 }
65 
66 static std::vector<std::pair<SourceLocation, StringRef>>
67 getCommentsInRange(ASTContext *Ctx, CharSourceRange Range) {
68  std::vector<std::pair<SourceLocation, StringRef>> Comments;
69  auto &SM = Ctx->getSourceManager();
70  std::pair<FileID, unsigned> BeginLoc = SM.getDecomposedLoc(Range.getBegin()),
71  EndLoc = SM.getDecomposedLoc(Range.getEnd());
72 
73  if (BeginLoc.first != EndLoc.first)
74  return Comments;
75 
76  bool Invalid = false;
77  StringRef Buffer = SM.getBufferData(BeginLoc.first, &Invalid);
78  if (Invalid)
79  return Comments;
80 
81  const char *StrData = Buffer.data() + BeginLoc.second;
82 
83  Lexer TheLexer(SM.getLocForStartOfFile(BeginLoc.first), Ctx->getLangOpts(),
84  Buffer.begin(), StrData, Buffer.end());
85  TheLexer.SetCommentRetentionState(true);
86 
87  while (true) {
88  Token Tok;
89  if (TheLexer.LexFromRawLexer(Tok))
90  break;
91  if (Tok.getLocation() == Range.getEnd() || Tok.is(tok::eof))
92  break;
93 
94  if (Tok.is(tok::comment)) {
95  std::pair<FileID, unsigned> CommentLoc =
96  SM.getDecomposedLoc(Tok.getLocation());
97  assert(CommentLoc.first == BeginLoc.first);
98  Comments.emplace_back(
99  Tok.getLocation(),
100  StringRef(Buffer.begin() + CommentLoc.second, Tok.getLength()));
101  } else {
102  // Clear comments found before the different token, e.g. comma.
103  Comments.clear();
104  }
105  }
106 
107  return Comments;
108 }
109 
110 static std::vector<std::pair<SourceLocation, StringRef>>
111 getCommentsBeforeLoc(ASTContext *Ctx, SourceLocation Loc) {
112  std::vector<std::pair<SourceLocation, StringRef>> Comments;
113  while (Loc.isValid()) {
114  clang::Token Tok = utils::lexer::getPreviousToken(
115  Loc, Ctx->getSourceManager(), Ctx->getLangOpts(),
116  /*SkipComments=*/false);
117  if (Tok.isNot(tok::comment))
118  break;
119  Loc = Tok.getLocation();
120  Comments.emplace_back(
121  Loc,
122  Lexer::getSourceText(CharSourceRange::getCharRange(
123  Loc, Loc.getLocWithOffset(Tok.getLength())),
124  Ctx->getSourceManager(), Ctx->getLangOpts()));
125  }
126  return Comments;
127 }
128 
129 static bool isLikelyTypo(llvm::ArrayRef<ParmVarDecl *> Params,
130  StringRef ArgName, unsigned ArgIndex) {
131  std::string ArgNameLowerStr = ArgName.lower();
132  StringRef ArgNameLower = ArgNameLowerStr;
133  // The threshold is arbitrary.
134  unsigned UpperBound = (ArgName.size() + 2) / 3 + 1;
135  unsigned ThisED = ArgNameLower.edit_distance(
136  Params[ArgIndex]->getIdentifier()->getName().lower(),
137  /*AllowReplacements=*/true, UpperBound);
138  if (ThisED >= UpperBound)
139  return false;
140 
141  for (unsigned I = 0, E = Params.size(); I != E; ++I) {
142  if (I == ArgIndex)
143  continue;
144  IdentifierInfo *II = Params[I]->getIdentifier();
145  if (!II)
146  continue;
147 
148  const unsigned Threshold = 2;
149  // Other parameters must be an edit distance at least Threshold more away
150  // from this parameter. This gives us greater confidence that this is a
151  // typo of this parameter and not one with a similar name.
152  unsigned OtherED = ArgNameLower.edit_distance(II->getName().lower(),
153  /*AllowReplacements=*/true,
154  ThisED + Threshold);
155  if (OtherED < ThisED + Threshold)
156  return false;
157  }
158 
159  return true;
160 }
161 
162 static bool sameName(StringRef InComment, StringRef InDecl, bool StrictMode) {
163  if (StrictMode)
164  return InComment == InDecl;
165  InComment = InComment.trim('_');
166  InDecl = InDecl.trim('_');
167  // FIXME: compare_lower only works for ASCII.
168  return InComment.compare_lower(InDecl) == 0;
169 }
170 
171 static bool looksLikeExpectMethod(const CXXMethodDecl *Expect) {
172  return Expect != nullptr && Expect->getLocation().isMacroID() &&
173  Expect->getNameInfo().getName().isIdentifier() &&
174  Expect->getName().startswith("gmock_");
175 }
176 static bool areMockAndExpectMethods(const CXXMethodDecl *Mock,
177  const CXXMethodDecl *Expect) {
178  assert(looksLikeExpectMethod(Expect));
179  return Mock != nullptr && Mock->getNextDeclInContext() == Expect &&
180  Mock->getNumParams() == Expect->getNumParams() &&
181  Mock->getLocation().isMacroID() &&
182  Mock->getNameInfo().getName().isIdentifier() &&
183  Mock->getName() == Expect->getName().substr(strlen("gmock_"));
184 }
185 
186 // This uses implementation details of MOCK_METHODx_ macros: for each mocked
187 // method M it defines M() with appropriate signature and a method used to set
188 // up expectations - gmock_M() - with each argument's type changed the
189 // corresponding matcher. This function returns M when given either M or
190 // gmock_M.
191 static const CXXMethodDecl *findMockedMethod(const CXXMethodDecl *Method) {
192  if (looksLikeExpectMethod(Method)) {
193  const DeclContext *Ctx = Method->getDeclContext();
194  if (Ctx == nullptr || !Ctx->isRecord())
195  return nullptr;
196  for (const auto *D : Ctx->decls()) {
197  if (D->getNextDeclInContext() == Method) {
198  const auto *Previous = dyn_cast<CXXMethodDecl>(D);
199  return areMockAndExpectMethods(Previous, Method) ? Previous : nullptr;
200  }
201  }
202  return nullptr;
203  }
204  if (const auto *Next =
205  dyn_cast_or_null<CXXMethodDecl>(Method->getNextDeclInContext())) {
206  if (looksLikeExpectMethod(Next) && areMockAndExpectMethods(Method, Next))
207  return Method;
208  }
209  return nullptr;
210 }
211 
212 // For gmock expectation builder method (the target of the call generated by
213 // `EXPECT_CALL(obj, Method(...))`) tries to find the real method being mocked
214 // (returns nullptr, if the mock method doesn't override anything). For other
215 // functions returns the function itself.
216 static const FunctionDecl *resolveMocks(const FunctionDecl *Func) {
217  if (const auto *Method = dyn_cast<CXXMethodDecl>(Func)) {
218  if (const auto *MockedMethod = findMockedMethod(Method)) {
219  // If mocked method overrides the real one, we can use its parameter
220  // names, otherwise we're out of luck.
221  if (MockedMethod->size_overridden_methods() > 0) {
222  return *MockedMethod->begin_overridden_methods();
223  }
224  return nullptr;
225  }
226  }
227  return Func;
228 }
229 
230 // Given the argument type and the options determine if we should
231 // be adding an argument comment.
232 bool ArgumentCommentCheck::shouldAddComment(const Expr *Arg) const {
233  if (Arg->getExprLoc().isMacroID())
234  return false;
235  Arg = Arg->IgnoreImpCasts();
236  return (CommentBoolLiterals && isa<CXXBoolLiteralExpr>(Arg)) ||
237  (CommentIntegerLiterals && isa<IntegerLiteral>(Arg)) ||
238  (CommentFloatLiterals && isa<FloatingLiteral>(Arg)) ||
239  (CommentUserDefinedLiterals && isa<UserDefinedLiteral>(Arg)) ||
240  (CommentCharacterLiterals && isa<CharacterLiteral>(Arg)) ||
241  (CommentStringLiterals && isa<StringLiteral>(Arg)) ||
242  (CommentNullPtrs && isa<CXXNullPtrLiteralExpr>(Arg));
243 }
244 
245 void ArgumentCommentCheck::checkCallArgs(ASTContext *Ctx,
246  const FunctionDecl *OriginalCallee,
247  SourceLocation ArgBeginLoc,
248  llvm::ArrayRef<const Expr *> Args) {
249  const FunctionDecl *Callee = resolveMocks(OriginalCallee);
250  if (!Callee)
251  return;
252 
253  Callee = Callee->getFirstDecl();
254  unsigned NumArgs = std::min<unsigned>(Args.size(), Callee->getNumParams());
255  if (NumArgs == 0)
256  return;
257 
258  auto MakeFileCharRange = [Ctx](SourceLocation Begin, SourceLocation End) {
259  return Lexer::makeFileCharRange(CharSourceRange::getCharRange(Begin, End),
260  Ctx->getSourceManager(),
261  Ctx->getLangOpts());
262  };
263 
264  for (unsigned I = 0; I < NumArgs; ++I) {
265  const ParmVarDecl *PVD = Callee->getParamDecl(I);
266  IdentifierInfo *II = PVD->getIdentifier();
267  if (!II)
268  continue;
269  if (auto Template = Callee->getTemplateInstantiationPattern()) {
270  // Don't warn on arguments for parameters instantiated from template
271  // parameter packs. If we find more arguments than the template
272  // definition has, it also means that they correspond to a parameter
273  // pack.
274  if (Template->getNumParams() <= I ||
275  Template->getParamDecl(I)->isParameterPack()) {
276  continue;
277  }
278  }
279 
280  CharSourceRange BeforeArgument =
281  MakeFileCharRange(ArgBeginLoc, Args[I]->getBeginLoc());
282  ArgBeginLoc = Args[I]->getEndLoc();
283 
284  std::vector<std::pair<SourceLocation, StringRef>> Comments;
285  if (BeforeArgument.isValid()) {
286  Comments = getCommentsInRange(Ctx, BeforeArgument);
287  } else {
288  // Fall back to parsing back from the start of the argument.
289  CharSourceRange ArgsRange = MakeFileCharRange(
290  Args[I]->getBeginLoc(), Args[NumArgs - 1]->getEndLoc());
291  Comments = getCommentsBeforeLoc(Ctx, ArgsRange.getBegin());
292  }
293 
294  for (auto Comment : Comments) {
295  llvm::SmallVector<StringRef, 2> Matches;
296  if (IdentRE.match(Comment.second, &Matches) &&
297  !sameName(Matches[2], II->getName(), StrictMode)) {
298  {
299  DiagnosticBuilder Diag =
300  diag(Comment.first, "argument name '%0' in comment does not "
301  "match parameter name %1")
302  << Matches[2] << II;
303  if (isLikelyTypo(Callee->parameters(), Matches[2], I)) {
304  Diag << FixItHint::CreateReplacement(
305  Comment.first, (Matches[1] + II->getName() + Matches[3]).str());
306  }
307  }
308  diag(PVD->getLocation(), "%0 declared here", DiagnosticIDs::Note) << II;
309  if (OriginalCallee != Callee) {
310  diag(OriginalCallee->getLocation(),
311  "actual callee (%0) is declared here", DiagnosticIDs::Note)
312  << OriginalCallee;
313  }
314  }
315  }
316 
317  // If the argument comments are missing for literals add them.
318  if (Comments.empty() && shouldAddComment(Args[I])) {
319  std::string ArgComment =
320  (llvm::Twine("/*") + II->getName() + "=*/").str();
321  DiagnosticBuilder Diag =
322  diag(Args[I]->getBeginLoc(),
323  "argument comment missing for literal argument %0")
324  << II
325  << FixItHint::CreateInsertion(Args[I]->getBeginLoc(), ArgComment);
326  }
327  }
328 } // namespace bugprone
329 
330 void ArgumentCommentCheck::check(const MatchFinder::MatchResult &Result) {
331  const auto *E = Result.Nodes.getNodeAs<Expr>("expr");
332  if (const auto *Call = dyn_cast<CallExpr>(E)) {
333  const FunctionDecl *Callee = Call->getDirectCallee();
334  if (!Callee)
335  return;
336 
337  checkCallArgs(Result.Context, Callee, Call->getCallee()->getEndLoc(),
338  llvm::makeArrayRef(Call->getArgs(), Call->getNumArgs()));
339  } else {
340  const auto *Construct = cast<CXXConstructExpr>(E);
341  if (Construct->getNumArgs() == 1 &&
342  Construct->getArg(0)->getSourceRange() == Construct->getSourceRange()) {
343  // Ignore implicit construction.
344  return;
345  }
346  checkCallArgs(
347  Result.Context, Construct->getConstructor(),
348  Construct->getParenOrBraceRange().getBegin(),
349  llvm::makeArrayRef(Construct->getArgs(), Construct->getNumArgs()));
350  }
351 }
352 
353 } // namespace bugprone
354 } // namespace tidy
355 } // namespace clang
SourceLocation Loc
&#39;#&#39; location in the include directive
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
static bool looksLikeExpectMethod(const CXXMethodDecl *Expect)
static const FunctionDecl * resolveMocks(const FunctionDecl *Func)
Token getPreviousToken(SourceLocation Location, const SourceManager &SM, const LangOptions &LangOpts, bool SkipComments)
Returns previous token or tok::unknown if not found.
Definition: LexerUtils.cpp:16
static std::vector< std::pair< SourceLocation, StringRef > > getCommentsBeforeLoc(ASTContext *Ctx, SourceLocation Loc)
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Base class for all clang-tidy checks.
static bool areMockAndExpectMethods(const CXXMethodDecl *Mock, const CXXMethodDecl *Expect)
static bool isLikelyTypo(llvm::ArrayRef< ParmVarDecl *> Params, StringRef ArgName, unsigned ArgIndex)
static std::vector< std::pair< SourceLocation, StringRef > > getCommentsInRange(ASTContext *Ctx, CharSourceRange Range)
Context Ctx
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.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
static constexpr llvm::StringLiteral Name
std::map< std::string, std::string > OptionMap
const Decl * D
Definition: XRefs.cpp:868
static char lower(char C)
Definition: FuzzyMatch.cpp:68
static bool sameName(StringRef InComment, StringRef InDecl, bool StrictMode)
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
static const CXXMethodDecl * findMockedMethod(const CXXMethodDecl *Method)
CharSourceRange Range
SourceRange for the file name.
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
Definition: Rename.cpp:36
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.