falho created this revision.
falho added reviewers: xazax.hun, o.gyorgy, alexfh, aaron.ballman, etienneb,
hokein, Prazek.
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This checker warns for the misuse of comparison operators
- char* is compared to a string literal
- inequality operator usage for NULL
Repository:
rL LLVM
https://reviews.llvm.org/D23427
Files:
clang-tidy/misc/CMakeLists.txt
clang-tidy/misc/ComparisonMisuseCheck.cpp
clang-tidy/misc/ComparisonMisuseCheck.h
clang-tidy/misc/MiscTidyModule.cpp
docs/clang-tidy/checks/list.rst
docs/clang-tidy/checks/misc-comparison-misuse.rst
test/clang-tidy/misc-comparison-misuse.cpp
Index: test/clang-tidy/misc-comparison-misuse.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/misc-comparison-misuse.cpp
@@ -0,0 +1,20 @@
+// RUN: %check_clang_tidy %s misc-comparison-misuse %t
+
+#define NULL __null
+
+bool test_pointer_to_literal(const char *my){
+ bool b = (my=="mystring");
+ // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: char* is compared to a string literal [misc-comparison-misuse]
+ return "mystring"==my;
+ // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: char* is compared to a string literal [misc-comparison-misuse]
+}
+
+void test_null_to_pointer(int *p){
+ if (NULL>=p);
+ // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: comparison to nullptr [misc-comparison-misuse]
+
+ if (NULL==p);
+
+ if (NULL!=p);
+}
+
Index: docs/clang-tidy/checks/misc-comparison-misuse.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/misc-comparison-misuse.rst
@@ -0,0 +1,25 @@
+.. title:: clang-tidy - misc-comparison-misuse
+
+misc-comparison-misuse
+======================
+
+This checker reports errors related to the misuse of the comparison operator.
+It should warn for the following cases:
+
+Case 1:
+ ``char*`` is compared to a string literal.
+
+.. code-block::
+ bool isMyString(const char * my){
+ return "mystring"==my;//error. comparing pointer to string literal
+ }
+
+
+Case 2:
+ Inequality operator usage for ``NULL``.
+
+.. code-block:: c++
+ void(int * p){
+ if (NULL>=p)//error, use only NULL==p, NULL!=p
+ }
+
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -55,6 +55,7 @@
misc-argument-comment
misc-assert-side-effect
misc-bool-pointer-implicit-conversion
+ misc-comparison-misuse
misc-dangling-handle
misc-definitions-in-headers
misc-fold-init-type
Index: clang-tidy/misc/MiscTidyModule.cpp
===================================================================
--- clang-tidy/misc/MiscTidyModule.cpp
+++ clang-tidy/misc/MiscTidyModule.cpp
@@ -15,6 +15,7 @@
#include "MisplacedConstCheck.h"
#include "UnconventionalAssignOperatorCheck.h"
#include "BoolPointerImplicitConversionCheck.h"
+#include "ComparisonMisuseCheck.h"
#include "DanglingHandleCheck.h"
#include "DefinitionsInHeadersCheck.h"
#include "FoldInitTypeCheck.h"
@@ -68,6 +69,8 @@
"misc-unconventional-assign-operator");
CheckFactories.registerCheck<BoolPointerImplicitConversionCheck>(
"misc-bool-pointer-implicit-conversion");
+ CheckFactories.registerCheck<ComparisonMisuseCheck>(
+ "misc-comparison-misuse");
CheckFactories.registerCheck<DanglingHandleCheck>(
"misc-dangling-handle");
CheckFactories.registerCheck<DefinitionsInHeadersCheck>(
Index: clang-tidy/misc/ComparisonMisuseCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/misc/ComparisonMisuseCheck.h
@@ -0,0 +1,39 @@
+//===--- ComparisonMisuseCheck.h - clang-tidy--------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_COMPARISON_MISUSE_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_COMPARISON_MISUSE_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+/// This checker reports errors related to the misuse of the comparison operator.
+/// It should warn for the following cases:
+/// - strcmp,strncmp,memcmp misuse.
+/// - char* is compared to a string literal
+/// - inequality operator usage for NULL
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/misc-comparison-misuse.html
+class ComparisonMisuseCheck : public ClangTidyCheck {
+public:
+ ComparisonMisuseCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_COMPARISON_MISUSE_H
Index: clang-tidy/misc/ComparisonMisuseCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/misc/ComparisonMisuseCheck.cpp
@@ -0,0 +1,52 @@
+//===--- ComparisonMisuseCheck.cpp - clang-tidy----------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ComparisonMisuseCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+void ComparisonMisuseCheck::registerMatchers(MatchFinder *Finder) {
+
+ Finder->addMatcher(
+ binaryOperator(hasEitherOperand(ignoringImpCasts(stringLiteral())),
+ hasEitherOperand(hasType(pointsTo(isAnyCharacter()))))
+ .bind("charToLiteral"),
+ this);
+
+ Finder->addMatcher(
+ binaryOperator(
+ unless(anyOf(hasOperatorName("=="), hasOperatorName("!="))),
+ hasEitherOperand(ignoringImpCasts(gnuNullExpr())))
+ .bind("compareToNull"),
+ this);
+}
+
+void ComparisonMisuseCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *CharToLiteral =
+ Result.Nodes.getNodeAs<BinaryOperator>("charToLiteral");
+ if (CharToLiteral)
+ diag(CharToLiteral->getOperatorLoc(),
+ "char* is compared to a string literal");
+
+ const auto *CompareToNull =
+ Result.Nodes.getNodeAs<BinaryOperator>("compareToNull");
+ if (CompareToNull)
+ diag(CompareToNull->getOperatorLoc(), "comparison to nullptr");
+}
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
+
Index: clang-tidy/misc/CMakeLists.txt
===================================================================
--- clang-tidy/misc/CMakeLists.txt
+++ clang-tidy/misc/CMakeLists.txt
@@ -5,6 +5,7 @@
AssertSideEffectCheck.cpp
MisplacedConstCheck.cpp
UnconventionalAssignOperatorCheck.cpp
+ ComparisonMisuseCheck.cpp
BoolPointerImplicitConversionCheck.cpp
DanglingHandleCheck.cpp
DefinitionsInHeadersCheck.cpp
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