clang-tools 6.0.0

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
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 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
28 void ProBoundsConstantArrayIndexCheck::storeOptions(
29 ClangTidyOptions::OptionMap &Opts) {
30 Options.store(Opts, "GslHeader", GslHeader);
31 Options.store(Opts, "IncludeStyle", IncludeStyle);
32 }
33
34 void ProBoundsConstantArrayIndexCheck::registerPPCallbacks(
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
44 void ProBoundsConstantArrayIndexCheck::registerMatchers(MatchFinder *Finder) {
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
67 void ProBoundsConstantArrayIndexCheck::check(
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->getLocEnd(), ")");
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
clang::ast_matchers
Definition: ClangTidyDiagnosticConsumer.h:27
clang::tidy::cppcoreguidelines::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:28
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:449
ProBoundsConstantArrayIndexCheck.h
Name
StringHandle Name
Definition: PreprocessorTracker.cpp:525
clang::tidy::ClangTidyCheck::getLangOpts
LangOptions getLangOpts() const
Returns the language options from the context.
Definition: ClangTidy.h:187
clang::tidy::cppcoreguidelines::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:67
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidy.h:127
clang::tidy::ClangTidyCheck::Options
OptionsView Options
Definition: ClangTidy.h:183
clang::tidy::ClangTidyOptions::OptionMap
std::map< std::string, std::string > OptionMap
Definition: ClangTidyOptions.h:99
clang::tidy::cppcoreguidelines::ProBoundsConstantArrayIndexCheck::registerPPCallbacks
void registerPPCallbacks(CompilerInstance &Compiler) override
Override this to register PPCallbacks with Compiler.
Definition: ProBoundsConstantArrayIndexCheck.cpp:34
clang
Definition: AndroidTidyModule.cpp:28
clang::tidy::utils::IncludeInserter
Produces fixes to insert specified includes to source files, if not yet present.
Definition: IncludeInserter.h:55
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:104
clang::tidy::cppcoreguidelines::ProBoundsConstantArrayIndexCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Definition: ProBoundsConstantArrayIndexCheck.cpp:44
clang::tidy::ClangTidyCheck::diag
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.
Definition: ClangTidy.cpp:416