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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
10 #include "ProBoundsConstantArrayIndexCheck.h"
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
21 ProBoundsConstantArrayIndexCheck::ProBoundsConstantArrayIndexCheck(
22 StringRef Name, ClangTidyContext *Context)
23 : ClangTidyCheck(Name, Context), GslHeader(Options.get("GslHeader", "")),
24 IncludeStyle(IncludeSorter::parseIncludeStyle(
25 Options.get("IncludeStyle", "llvm"))) {}
26
27 void ProBoundsConstantArrayIndexCheck::storeOptions(
28 ClangTidyOptions::OptionMap &Opts) {
29 Options.store(Opts, "GslHeader", GslHeader);
30 Options.store(Opts, "IncludeStyle", IncludeStyle);
31 }
32
33 void ProBoundsConstantArrayIndexCheck::registerPPCallbacks(
34 CompilerInstance &Compiler) {
35 if (!getLangOpts().CPlusPlus)
36 return;
37
38 Inserter.reset(new IncludeInserter(Compiler.getSourceManager(),
39 Compiler.getLangOpts(), IncludeStyle));
40 Compiler.getPreprocessor().addPPCallbacks(Inserter->CreatePPCallbacks());
41 }
42
43 void ProBoundsConstantArrayIndexCheck::registerMatchers(MatchFinder *Finder) {
44 if (!getLangOpts().CPlusPlus)
45 return;
46
47 Finder->addMatcher(arraySubscriptExpr(hasBase(ignoringImpCasts(hasType(
48 constantArrayType().bind("type")))),
49 hasIndex(expr().bind("index")))
50 .bind("expr"),
51 this);
52
53 Finder->addMatcher(
54 cxxOperatorCallExpr(
55 hasOverloadedOperatorName("[]"),
56 hasArgument(
57 0, hasType(cxxRecordDecl(hasName("::std::array")).bind("type"))),
58 hasArgument(1, expr().bind("index")))
59 .bind("expr"),
60 this);
61 }
62
63 void ProBoundsConstantArrayIndexCheck::check(
64 const MatchFinder::MatchResult &Result) {
65 const auto *Matched = Result.Nodes.getNodeAs<Expr>("expr");
66 const auto *IndexExpr = Result.Nodes.getNodeAs<Expr>("index");
67 llvm::APSInt Index;
68 if (!IndexExpr->isIntegerConstantExpr(Index, *Result.Context, nullptr,
69 /*isEvaluated=*/true)) {
70 SourceRange BaseRange;
71 if (const auto *ArraySubscriptE = dyn_cast<ArraySubscriptExpr>(Matched))
72 BaseRange = ArraySubscriptE->getBase()->getSourceRange();
73 else
74 BaseRange =
75 dyn_cast<CXXOperatorCallExpr>(Matched)->getArg(0)->getSourceRange();
76 SourceRange IndexRange = IndexExpr->getSourceRange();
77
78 auto Diag = diag(Matched->getExprLoc(),
79 "do not use array subscript when the index is "
80 "not an integer constant expression; use gsl::at() "
81 "instead");
82 if (!GslHeader.empty()) {
83 Diag << FixItHint::CreateInsertion(BaseRange.getBegin(), "gsl::at(")
84 << FixItHint::CreateReplacement(
85 SourceRange(BaseRange.getEnd().getLocWithOffset(1),
86 IndexRange.getBegin().getLocWithOffset(-1)),
87 ", ")
88 << FixItHint::CreateReplacement(Matched->getLocEnd(), ")");
89
90 Optional<FixItHint> Insertion = Inserter->CreateIncludeInsertion(
91 Result.SourceManager->getMainFileID(), GslHeader,
92 /*IsAngled=*/false);
93 if (Insertion)
94 Diag << Insertion.getValue();
95 }
96 return;
97 }
98
99 const auto *StdArrayDecl =
100 Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("type");
101
102 // For static arrays, this is handled in clang-diagnostic-array-bounds.
103 if (!StdArrayDecl)
104 return;
105
106 if (Index.isSigned() && Index.isNegative()) {
107 diag(Matched->getExprLoc(),
108 "std::array<> index %0 is negative")
109 << Index.toString(10);
110 return;
111 }
112
113 const TemplateArgumentList &TemplateArgs = StdArrayDecl->getTemplateArgs();
114 if (TemplateArgs.size() < 2)
115 return;
116 // First template arg of std::array is the type, second arg is the size.
117 const auto &SizeArg = TemplateArgs[1];
118 if (SizeArg.getKind() != TemplateArgument::Integral)
119 return;
120 llvm::APInt ArraySize = SizeArg.getAsIntegral();
121
122 // Get uint64_t values, because different bitwidths would lead to an assertion
123 // in APInt::uge.
124 if (Index.getZExtValue() >= ArraySize.getZExtValue()) {
125 diag(Matched->getExprLoc(), "std::array<> index %0 is past the end of the array "
126 "(which contains %1 elements)")
127 << Index.toString(10) << ArraySize.toString(10, false);
128 }
129 }
130
131 } // namespace tidy
132 } // namespace clang
ProBoundsConstantArrayIndexCheck.h
clang::tidy::ClangTidyCheck::getLangOpts
LangOptions getLangOpts() const
Returns the language options from the context.
Definition: ClangTidy.h:162
clang::tidy::ProBoundsConstantArrayIndexCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register ASTMatchers with Finder.
Definition: ProBoundsConstantArrayIndexCheck.cpp:43
clang::tidy::ProBoundsConstantArrayIndexCheck::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: ProBoundsConstantArrayIndexCheck.cpp:27
Name
StringHandle Name
Definition: PreprocessorTracker.cpp:525
Finder
std::unique_ptr< ast_matchers::MatchFinder > Finder
Definition: ClangTidy.cpp:188
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidy.h:102
clang::tidy::ClangTidyCheck::Options
OptionsView Options
Definition: ClangTidy.h:158
clang::tidy::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: ClangTidy.cpp:344
clang::tidy::ProBoundsConstantArrayIndexCheck::check
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Definition: ProBoundsConstantArrayIndexCheck.cpp:63
clang::tidy::ClangTidyOptions::OptionMap
std::map< std::string, std::string > OptionMap
Definition: ClangTidyOptions.h:82
clang::tidy::IncludeSorter
Definition: IncludeSorter.h:23
Context
ClangTidyContext & Context
Definition: ClangTidy.cpp:93
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:124
clang::tidy::IncludeInserter
Definition: IncludeInserter.h:47
clang::tidy::ProBoundsConstantArrayIndexCheck::registerPPCallbacks
void registerPPCallbacks(CompilerInstance &Compiler) override
Override this to register PPCallbacks with Compiler.
Definition: ProBoundsConstantArrayIndexCheck.cpp:33
clang::tidy::ClangTidyCheck::diag
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
Definition: ClangTidy.cpp:323
Result
const NamedDecl * Result
Definition: USRFinder.cpp:121