clang-tools 10.0.0

SignedBitwiseCheck.cpp
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1 //===--- SignedBitwiseCheck.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 "SignedBitwiseCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12
13 using namespace clang::ast_matchers;
14 using namespace clang::ast_matchers::internal;
15
16 namespace clang {
17 namespace tidy {
18 namespace hicpp {
19
20 SignedBitwiseCheck::SignedBitwiseCheck(StringRef Name,
21 ClangTidyContext *Context)
22 : ClangTidyCheck(Name, Context),
23 IgnorePositiveIntegerLiterals(
24 Options.get("IgnorePositiveIntegerLiterals", false)) {}
25
26 void SignedBitwiseCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
27 Options.store(Opts, "IgnorePositiveIntegerLiterals",
28 IgnorePositiveIntegerLiterals);
29 }
30
31 void SignedBitwiseCheck::registerMatchers(MatchFinder *Finder) {
32 const auto SignedIntegerOperand =
33 (IgnorePositiveIntegerLiterals
34 ? expr(ignoringImpCasts(hasType(isSignedInteger())),
35 unless(integerLiteral()))
36 : expr(ignoringImpCasts(hasType(isSignedInteger()))))
37 .bind("signed-operand");
38
39 // The standard [bitmask.types] allows some integral types to be implemented
40 // as signed types. Exclude these types from diagnosing for bitwise or(|) and
41 // bitwise and(&). Shifting and complementing such values is still not
42 // allowed.
43 const auto BitmaskType = namedDecl(
44 hasAnyName("::std::locale::category", "::std::ctype_base::mask",
45 "::std::ios_base::fmtflags", "::std::ios_base::iostate",
46 "::std::ios_base::openmode"));
47 const auto IsStdBitmask = ignoringImpCasts(declRefExpr(hasType(BitmaskType)));
48
49 // Match binary bitwise operations on signed integer arguments.
50 Finder->addMatcher(
51 binaryOperator(anyOf(hasOperatorName("^"), hasOperatorName("|"),
52 hasOperatorName("&"), hasOperatorName("^="),
53 hasOperatorName("|="), hasOperatorName("&=")),
54
55 unless(allOf(hasLHS(IsStdBitmask), hasRHS(IsStdBitmask))),
56
57 hasEitherOperand(SignedIntegerOperand),
58 hasLHS(hasType(isInteger())), hasRHS(hasType(isInteger())))
59 .bind("binary-no-sign-interference"),
60 this);
61
62 // Shifting and complement is not allowed for any signed integer type because
63 // the sign bit may corrupt the result.
64 Finder->addMatcher(
65 binaryOperator(anyOf(hasOperatorName("<<"), hasOperatorName(">>"),
66 hasOperatorName("<<="), hasOperatorName(">>=")),
67 hasEitherOperand(SignedIntegerOperand),
68 hasLHS(hasType(isInteger())), hasRHS(hasType(isInteger())))
69 .bind("binary-sign-interference"),
70 this);
71
72 // Match unary operations on signed integer types.
73 Finder->addMatcher(
74 unaryOperator(hasOperatorName("~"), hasUnaryOperand(SignedIntegerOperand))
75 .bind("unary-signed"),
76 this);
77 }
78
79 void SignedBitwiseCheck::check(const MatchFinder::MatchResult &Result) {
80 const ast_matchers::BoundNodes &N = Result.Nodes;
81 const auto *SignedOperand = N.getNodeAs<Expr>("signed-operand");
82 assert(SignedOperand &&
83 "No signed operand found in problematic bitwise operations");
84
85 bool IsUnary = false;
86 SourceLocation Location;
87
88 if (const auto *UnaryOp = N.getNodeAs<UnaryOperator>("unary-signed")) {
89 IsUnary = true;
90 Location = UnaryOp->getBeginLoc();
91 } else {
92 if (const auto *BinaryOp =
93 N.getNodeAs<BinaryOperator>("binary-no-sign-interference"))
94 Location = BinaryOp->getBeginLoc();
95 else if (const auto *BinaryOp =
96 N.getNodeAs<BinaryOperator>("binary-sign-interference"))
97 Location = BinaryOp->getBeginLoc();
98 else
99 llvm_unreachable("unexpected matcher result");
100 }
101 diag(Location, "use of a signed integer operand with a "
102 "%select{binary|unary}0 bitwise operator")
103 << IsUnary << SignedOperand->getSourceRange();
104 }
105
106 } // namespace hicpp
107 } // namespace tidy
108 } // namespace clang
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidyCheck.h:47
clang::tidy::ClangTidyCheck::Options
OptionsView Options
Definition: ClangTidyCheck.h:184
SignedBitwiseCheck.h
clang::tidy::ClangTidyCheck::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: ClangTidyCheck.cpp:58
Name
static constexpr llvm::StringLiteral Name
Definition: UppercaseLiteralSuffixCheck.cpp:27
clang::tidy::ClangTidyOptions::OptionMap
std::map< std::string, std::string > OptionMap
Definition: ClangTidyOptions.h:97
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
internal
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:77
clang::tidy::hicpp::SignedBitwiseCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Definition: SignedBitwiseCheck.cpp:31
clang::tidy::hicpp::SignedBitwiseCheck::storeOptions
void storeOptions(ClangTidyOptions::OptionMap &Options) override
Should store all options supported by this check with their current values or default values for opti...
Definition: SignedBitwiseCheck.cpp:26
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: ClangTidyCheck.cpp:21
clang::tidy::hicpp::SignedBitwiseCheck::check
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Definition: SignedBitwiseCheck.cpp:79
Location
Definition: Modularize.cpp:383