clang-tools  8.0.0
ProBoundsConstantArrayIndexCheck.cpp
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1 //===--- ProBoundsConstantArrayIndexCheck.cpp - clang-tidy-----------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Frontend/CompilerInstance.h"
14 #include "clang/Lex/Preprocessor.h"
15 
16 using namespace clang::ast_matchers;
17 
18 namespace clang {
19 namespace tidy {
20 namespace cppcoreguidelines {
21 
22 ProBoundsConstantArrayIndexCheck::ProBoundsConstantArrayIndexCheck(
23  StringRef Name, ClangTidyContext *Context)
24  : ClangTidyCheck(Name, Context), GslHeader(Options.get("GslHeader", "")),
25  IncludeStyle(utils::IncludeSorter::parseIncludeStyle(
26  Options.getLocalOrGlobal("IncludeStyle", "llvm"))) {}
27 
30  Options.store(Opts, "GslHeader", GslHeader);
31  Options.store(Opts, "IncludeStyle", IncludeStyle);
32 }
33 
35  CompilerInstance &Compiler) {
36  if (!getLangOpts().CPlusPlus)
37  return;
38 
39  Inserter.reset(new utils::IncludeInserter(
40  Compiler.getSourceManager(), Compiler.getLangOpts(), IncludeStyle));
41  Compiler.getPreprocessor().addPPCallbacks(Inserter->CreatePPCallbacks());
42 }
43 
45  if (!getLangOpts().CPlusPlus)
46  return;
47 
48  // Note: if a struct contains an array member, the compiler-generated
49  // constructor has an arraySubscriptExpr.
50  Finder->addMatcher(
51  arraySubscriptExpr(
52  hasBase(ignoringImpCasts(hasType(constantArrayType().bind("type")))),
53  hasIndex(expr().bind("index")), unless(hasAncestor(isImplicit())))
54  .bind("expr"),
55  this);
56 
57  Finder->addMatcher(
58  cxxOperatorCallExpr(
59  hasOverloadedOperatorName("[]"),
60  hasArgument(
61  0, hasType(cxxRecordDecl(hasName("::std::array")).bind("type"))),
62  hasArgument(1, expr().bind("index")))
63  .bind("expr"),
64  this);
65 }
66 
68  const MatchFinder::MatchResult &Result) {
69  const auto *Matched = Result.Nodes.getNodeAs<Expr>("expr");
70  const auto *IndexExpr = Result.Nodes.getNodeAs<Expr>("index");
71 
72  if (IndexExpr->isValueDependent())
73  return; // We check in the specialization.
74 
75  llvm::APSInt Index;
76  if (!IndexExpr->isIntegerConstantExpr(Index, *Result.Context, nullptr,
77  /*isEvaluated=*/true)) {
78  SourceRange BaseRange;
79  if (const auto *ArraySubscriptE = dyn_cast<ArraySubscriptExpr>(Matched))
80  BaseRange = ArraySubscriptE->getBase()->getSourceRange();
81  else
82  BaseRange =
83  dyn_cast<CXXOperatorCallExpr>(Matched)->getArg(0)->getSourceRange();
84  SourceRange IndexRange = IndexExpr->getSourceRange();
85 
86  auto Diag = diag(Matched->getExprLoc(),
87  "do not use array subscript when the index is "
88  "not an integer constant expression; use gsl::at() "
89  "instead");
90  if (!GslHeader.empty()) {
91  Diag << FixItHint::CreateInsertion(BaseRange.getBegin(), "gsl::at(")
92  << FixItHint::CreateReplacement(
93  SourceRange(BaseRange.getEnd().getLocWithOffset(1),
94  IndexRange.getBegin().getLocWithOffset(-1)),
95  ", ")
96  << FixItHint::CreateReplacement(Matched->getEndLoc(), ")");
97 
98  Optional<FixItHint> Insertion = Inserter->CreateIncludeInsertion(
99  Result.SourceManager->getMainFileID(), GslHeader,
100  /*IsAngled=*/false);
101  if (Insertion)
102  Diag << Insertion.getValue();
103  }
104  return;
105  }
106 
107  const auto *StdArrayDecl =
108  Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("type");
109 
110  // For static arrays, this is handled in clang-diagnostic-array-bounds.
111  if (!StdArrayDecl)
112  return;
113 
114  if (Index.isSigned() && Index.isNegative()) {
115  diag(Matched->getExprLoc(), "std::array<> index %0 is negative")
116  << Index.toString(10);
117  return;
118  }
119 
120  const TemplateArgumentList &TemplateArgs = StdArrayDecl->getTemplateArgs();
121  if (TemplateArgs.size() < 2)
122  return;
123  // First template arg of std::array is the type, second arg is the size.
124  const auto &SizeArg = TemplateArgs[1];
125  if (SizeArg.getKind() != TemplateArgument::Integral)
126  return;
127  llvm::APInt ArraySize = SizeArg.getAsIntegral();
128 
129  // Get uint64_t values, because different bitwidths would lead to an assertion
130  // in APInt::uge.
131  if (Index.getZExtValue() >= ArraySize.getZExtValue()) {
132  diag(Matched->getExprLoc(),
133  "std::array<> index %0 is past the end of the array "
134  "(which contains %1 elements)")
135  << Index.toString(10) << ArraySize.toString(10, false);
136  }
137 }
138 
139 } // namespace cppcoreguidelines
140 } // namespace tidy
141 } // namespace clang
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
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: ClangTidy.cpp:473
LangOptions getLangOpts() const
Returns the language options from the context.
Definition: ClangTidy.h:187
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.
Definition: ClangTidy.h:127
static constexpr llvm::StringLiteral Name
std::map< std::string, std::string > OptionMap
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
void registerPPCallbacks(CompilerInstance &Compiler) override
Override this to register PPCallbacks with Compiler.
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Produces fixes to insert specified includes to source files, if not yet present.
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.
Definition: ClangTidy.cpp:438
const SymbolIndex * Index
Definition: Dexp.cpp:85