clang-tools  9.0.0
ProBoundsConstantArrayIndexCheck.cpp
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1 //===--- ProBoundsConstantArrayIndexCheck.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 
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Frontend/CompilerInstance.h"
13 #include "clang/Lex/Preprocessor.h"
14 
15 using namespace clang::ast_matchers;
16 
17 namespace clang {
18 namespace tidy {
19 namespace cppcoreguidelines {
20 
21 ProBoundsConstantArrayIndexCheck::ProBoundsConstantArrayIndexCheck(
22  StringRef Name, ClangTidyContext *Context)
23  : ClangTidyCheck(Name, Context), GslHeader(Options.get("GslHeader", "")),
24  IncludeStyle(utils::IncludeSorter::parseIncludeStyle(
25  Options.getLocalOrGlobal("IncludeStyle", "llvm"))) {}
26 
29  Options.store(Opts, "GslHeader", GslHeader);
30  Options.store(Opts, "IncludeStyle", IncludeStyle);
31 }
32 
34  const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
35  if (!getLangOpts().CPlusPlus)
36  return;
37 
38  Inserter = llvm::make_unique<utils::IncludeInserter>(SM, getLangOpts(),
39  IncludeStyle);
40  PP->addPPCallbacks(Inserter->CreatePPCallbacks());
41 }
42 
44  if (!getLangOpts().CPlusPlus)
45  return;
46 
47  // Note: if a struct contains an array member, the compiler-generated
48  // constructor has an arraySubscriptExpr.
49  Finder->addMatcher(
50  arraySubscriptExpr(
51  hasBase(ignoringImpCasts(hasType(constantArrayType().bind("type")))),
52  hasIndex(expr().bind("index")), unless(hasAncestor(isImplicit())))
53  .bind("expr"),
54  this);
55 
56  Finder->addMatcher(
57  cxxOperatorCallExpr(
58  hasOverloadedOperatorName("[]"),
59  hasArgument(
60  0, hasType(cxxRecordDecl(hasName("::std::array")).bind("type"))),
61  hasArgument(1, expr().bind("index")))
62  .bind("expr"),
63  this);
64 }
65 
67  const MatchFinder::MatchResult &Result) {
68  const auto *Matched = Result.Nodes.getNodeAs<Expr>("expr");
69  const auto *IndexExpr = Result.Nodes.getNodeAs<Expr>("index");
70 
71  if (IndexExpr->isValueDependent())
72  return; // We check in the specialization.
73 
74  llvm::APSInt Index;
75  if (!IndexExpr->isIntegerConstantExpr(Index, *Result.Context, nullptr,
76  /*isEvaluated=*/true)) {
77  SourceRange BaseRange;
78  if (const auto *ArraySubscriptE = dyn_cast<ArraySubscriptExpr>(Matched))
79  BaseRange = ArraySubscriptE->getBase()->getSourceRange();
80  else
81  BaseRange =
82  dyn_cast<CXXOperatorCallExpr>(Matched)->getArg(0)->getSourceRange();
83  SourceRange IndexRange = IndexExpr->getSourceRange();
84 
85  auto Diag = diag(Matched->getExprLoc(),
86  "do not use array subscript when the index is "
87  "not an integer constant expression; use gsl::at() "
88  "instead");
89  if (!GslHeader.empty()) {
90  Diag << FixItHint::CreateInsertion(BaseRange.getBegin(), "gsl::at(")
91  << FixItHint::CreateReplacement(
92  SourceRange(BaseRange.getEnd().getLocWithOffset(1),
93  IndexRange.getBegin().getLocWithOffset(-1)),
94  ", ")
95  << FixItHint::CreateReplacement(Matched->getEndLoc(), ")");
96 
97  Optional<FixItHint> Insertion = Inserter->CreateIncludeInsertion(
98  Result.SourceManager->getMainFileID(), GslHeader,
99  /*IsAngled=*/false);
100  if (Insertion)
101  Diag << Insertion.getValue();
102  }
103  return;
104  }
105 
106  const auto *StdArrayDecl =
107  Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("type");
108 
109  // For static arrays, this is handled in clang-diagnostic-array-bounds.
110  if (!StdArrayDecl)
111  return;
112 
113  if (Index.isSigned() && Index.isNegative()) {
114  diag(Matched->getExprLoc(), "std::array<> index %0 is negative")
115  << Index.toString(10);
116  return;
117  }
118 
119  const TemplateArgumentList &TemplateArgs = StdArrayDecl->getTemplateArgs();
120  if (TemplateArgs.size() < 2)
121  return;
122  // First template arg of std::array is the type, second arg is the size.
123  const auto &SizeArg = TemplateArgs[1];
124  if (SizeArg.getKind() != TemplateArgument::Integral)
125  return;
126  llvm::APInt ArraySize = SizeArg.getAsIntegral();
127 
128  // Get uint64_t values, because different bitwidths would lead to an assertion
129  // in APInt::uge.
130  if (Index.getZExtValue() >= ArraySize.getZExtValue()) {
131  diag(Matched->getExprLoc(),
132  "std::array<> index %0 is past the end of the array "
133  "(which contains %1 elements)")
134  << Index.toString(10) << ArraySize.toString(10, false);
135  }
136 }
137 
138 } // namespace cppcoreguidelines
139 } // namespace tidy
140 } // 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 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.
const LangOptions & getLangOpts() const
Returns the language options from the context.
void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) override
Override this to register PPCallbacks in the preprocessor.
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.
static constexpr llvm::StringLiteral Name
std::map< std::string, std::string > OptionMap
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
Definition: Rename.cpp:36
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.
const SymbolIndex * Index
Definition: Dexp.cpp:84