Bug Summary

File:clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
Warning:line 74, column 11
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name ProBoundsConstantArrayIndexCheck.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/build-llvm/tools/clang/stage2-bins -resource-dir /usr/lib/llvm-15/lib/clang/15.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I tools/clang/tools/extra/clang-tidy/cppcoreguidelines -I /build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/clang-tools-extra/clang-tidy/cppcoreguidelines -I tools/clang/tools/extra/clang-tidy -I /build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/clang/include -I tools/clang/include -I include -I /build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/llvm/include -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-15/lib/clang/15.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fmacro-prefix-map=/build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/= -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/= -O3 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/build-llvm/tools/clang/stage2-bins -fdebug-prefix-map=/build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fdebug-prefix-map=/build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2022-02-12-012820-35430-1 -x c++ /build/llvm-toolchain-snapshot-15~++20220211101351+43a1756a5d53/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
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
9#include "ProBoundsConstantArrayIndexCheck.h"
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
15using namespace clang::ast_matchers;
16
17namespace clang {
18namespace tidy {
19namespace cppcoreguidelines {
20
21ProBoundsConstantArrayIndexCheck::ProBoundsConstantArrayIndexCheck(
22 StringRef Name, ClangTidyContext *Context)
23 : ClangTidyCheck(Name, Context), GslHeader(Options.get("GslHeader", "")),
24 Inserter(Options.getLocalOrGlobal("IncludeStyle",
25 utils::IncludeSorter::IS_LLVM)) {}
26
27void ProBoundsConstantArrayIndexCheck::storeOptions(
28 ClangTidyOptions::OptionMap &Opts) {
29 Options.store(Opts, "GslHeader", GslHeader);
30 Options.store(Opts, "IncludeStyle", Inserter.getStyle());
31}
32
33void ProBoundsConstantArrayIndexCheck::registerPPCallbacks(
34 const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
35 Inserter.registerPreprocessor(PP);
36}
37
38void ProBoundsConstantArrayIndexCheck::registerMatchers(MatchFinder *Finder) {
39 // Note: if a struct contains an array member, the compiler-generated
40 // constructor has an arraySubscriptExpr.
41 Finder->addMatcher(arraySubscriptExpr(hasBase(ignoringImpCasts(hasType(
42 constantArrayType().bind("type")))),
43 hasIndex(expr().bind("index")),
44 unless(hasAncestor(decl(isImplicit()))))
45 .bind("expr"),
46 this);
47
48 Finder->addMatcher(
49 cxxOperatorCallExpr(
50 hasOverloadedOperatorName("[]"),
51 hasArgument(
52 0, hasType(cxxRecordDecl(hasName("::std::array")).bind("type"))),
53 hasArgument(1, expr().bind("index")))
54 .bind("expr"),
55 this);
56}
57
58void ProBoundsConstantArrayIndexCheck::check(
59 const MatchFinder::MatchResult &Result) {
60 const auto *Matched = Result.Nodes.getNodeAs<Expr>("expr");
61 const auto *IndexExpr = Result.Nodes.getNodeAs<Expr>("index");
62
63 if (IndexExpr->isValueDependent())
1
Assuming the condition is false
→
2
←
Taking false branch
→
64 return; // We check in the specialization.
65
66 Optional<llvm::APSInt> Index =
67 IndexExpr->getIntegerConstantExpr(*Result.Context);
68 if (!Index) {
3
←
Assuming the condition is true
→
4
←
Taking true branch
→
69 SourceRange BaseRange;
70 if (const auto *ArraySubscriptE
5.1
'ArraySubscriptE' is null
 = dyn_cast<ArraySubscriptExpr>(Matched))
5
←
Assuming 'Matched' is not a 'ArraySubscriptExpr'
→
6
←
Taking false branch
→
71 BaseRange = ArraySubscriptE->getBase()->getSourceRange();
72 else
73 BaseRange =
74 dyn_cast<CXXOperatorCallExpr>(Matched)->getArg(0)->getSourceRange();
7
←
Assuming 'Matched' is not a 'CXXOperatorCallExpr'
→
8
←
Called C++ object pointer is null
75 SourceRange IndexRange = IndexExpr->getSourceRange();
76
77 auto Diag = diag(Matched->getExprLoc(),
78 "do not use array subscript when the index is "
79 "not an integer constant expression");
80 if (!GslHeader.empty()) {
81 Diag << FixItHint::CreateInsertion(BaseRange.getBegin(), "gsl::at(")
82 << FixItHint::CreateReplacement(
83 SourceRange(BaseRange.getEnd().getLocWithOffset(1),
84 IndexRange.getBegin().getLocWithOffset(-1)),
85 ", ")
86 << FixItHint::CreateReplacement(Matched->getEndLoc(), ")")
87 << Inserter.createMainFileIncludeInsertion(GslHeader);
88 }
89 return;
90 }
91
92 const auto *StdArrayDecl =
93 Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("type");
94
95 // For static arrays, this is handled in clang-diagnostic-array-bounds.
96 if (!StdArrayDecl)
97 return;
98
99 if (Index->isSigned() && Index->isNegative()) {
100 diag(Matched->getExprLoc(), "std::array<> index %0 is negative")
101 << toString(*Index, 10);
102 return;
103 }
104
105 const TemplateArgumentList &TemplateArgs = StdArrayDecl->getTemplateArgs();
106 if (TemplateArgs.size() < 2)
107 return;
108 // First template arg of std::array is the type, second arg is the size.
109 const auto &SizeArg = TemplateArgs[1];
110 if (SizeArg.getKind() != TemplateArgument::Integral)
111 return;
112 llvm::APInt ArraySize = SizeArg.getAsIntegral();
113
114 // Get uint64_t values, because different bitwidths would lead to an assertion
115 // in APInt::uge.
116 if (Index->getZExtValue() >= ArraySize.getZExtValue()) {
117 diag(Matched->getExprLoc(),
118 "std::array<> index %0 is past the end of the array "
119 "(which contains %1 elements)")
120 << toString(*Index, 10) << toString(ArraySize, 10, false);
121 }
122}
123
124} // namespace cppcoreguidelines
125} // namespace tidy
126} // namespace clang