SilverGeri updated this revision to Diff 81458.
https://reviews.llvm.org/D21298
Files:
clang-tidy/readability/CMakeLists.txt
clang-tidy/readability/DeleteNullPointerCheck.cpp
clang-tidy/readability/DeleteNullPointerCheck.h
clang-tidy/readability/ReadabilityTidyModule.cpp
docs/clang-tidy/checks/list.rst
docs/clang-tidy/checks/readability-delete-null-pointer.rst
test/clang-tidy/readability-delete-null-pointer.cpp
Index: test/clang-tidy/readability-delete-null-pointer.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/readability-delete-null-pointer.cpp
@@ -0,0 +1,73 @@
+// RUN: %check_clang_tidy %s readability-delete-null-pointer %t
+
+#define NULL 0
+
+void f() {
+ int *p = 0;
+ // CHECK-FIXES: // comment that should not be deleted
+ if (p) {
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: 'if' statement is unnecessary; deleting null pointer has no effect [readability-delete-null-pointer]
+ // comment that should not be deleted
+ delete p;
+ }
+ // CHECK-FIXES-NOT: if (p) {
+ // CHECK-FIXES: delete p;
+
+
+ int *p2 = new int[3];
+ // CHECK-FIXES: // another comment to keep
+ if (p2)
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: 'if' statement is unnecessary;
+ // another comment to keep
+ delete[] p2;
+ // CHECK-FIXES-NOT: if (p2)
+ // CHECK-FIXES: delete[] p2;
+
+ int *p3 = 0;
+ if (NULL != p3) {
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: 'if' statement is unnecessary;
+ delete p3;
+ }
+ // CHECK-FIXES-NOT: if (NULL != p3) {
+ // CHECK-FIXES: delete p3;
+
+ int *p4 = nullptr;
+ if (p4 != nullptr) {
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: 'if' statement is unnecessary;
+ delete p4;
+ }
+ // CHECK-FIXES-NOT: if (p4 != nullptr) {
+ // CHECK-FIXES: delete p4;
+
+ char *c;
+ if (c != 0) {
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: 'if' statement is unnecessary;
+ delete c;
+ }
+ // CHECK-FIXES-NOT: if (c != 0) {
+ // CHECK-FIXES: delete c;
+
+ char *c2;
+ if (c2) {
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: 'if' statement is unnecessary;
+ // CHECK-FIXES: } else {
+ // CHECK-FIXES: c2 = c;
+ delete c2;
+ } else {
+ c2 = c;
+ }
+}
+
+void g() {
+ int *p5, *p6;
+ if (p5)
+ delete p6;
+
+ if (p5 && p6)
+ delete p5;
+
+ if (p6) {
+ int x = 5;
+ delete p6;
+ }
+}
Index: docs/clang-tidy/checks/readability-delete-null-pointer.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/readability-delete-null-pointer.rst
@@ -0,0 +1,12 @@
+.. title:: clang-tidy - readability-delete-null-pointer
+
+readability-delete-null-pointer
+===============================
+
+Checks the 'if' statements where a pointer's existence is checked and then deletes the pointer.
+The check is unnecessary as deleting a nullpointer has no effect.
+
+.. code:: c++
+ int *p;
+ if (p)
+ delete p;
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -127,6 +127,7 @@
readability-avoid-const-params-in-decls
readability-braces-around-statements
readability-container-size-empty
+ readability-delete-null-pointer
readability-deleted-default
readability-else-after-return
readability-function-size
Index: clang-tidy/readability/ReadabilityTidyModule.cpp
===================================================================
--- clang-tidy/readability/ReadabilityTidyModule.cpp
+++ clang-tidy/readability/ReadabilityTidyModule.cpp
@@ -13,6 +13,7 @@
#include "AvoidConstParamsInDecls.h"
#include "BracesAroundStatementsCheck.h"
#include "ContainerSizeEmptyCheck.h"
+#include "DeleteNullPointerCheck.h"
#include "DeletedDefaultCheck.h"
#include "ElseAfterReturnCheck.h"
#include "FunctionSizeCheck.h"
@@ -45,6 +46,8 @@
"readability-braces-around-statements");
CheckFactories.registerCheck<ContainerSizeEmptyCheck>(
"readability-container-size-empty");
+ CheckFactories.registerCheck<DeleteNullPointerCheck>(
+ "readability-delete-null-pointer");
CheckFactories.registerCheck<DeletedDefaultCheck>(
"readability-deleted-default");
CheckFactories.registerCheck<ElseAfterReturnCheck>(
Index: clang-tidy/readability/DeleteNullPointerCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/readability/DeleteNullPointerCheck.h
@@ -0,0 +1,35 @@
+//===--- DeleteNullPointerCheck.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_READABILITY_DELETE_NULL_POINTER_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_DELETE_NULL_POINTER_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+/// Check whether the 'if' statement is unnecessary before calling 'delete' on a pointer.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/readability-delete-null-pointer.html
+class DeleteNullPointerCheck : public ClangTidyCheck {
+public:
+ DeleteNullPointerCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_DELETE_NULL_POINTER_H
Index: clang-tidy/readability/DeleteNullPointerCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/readability/DeleteNullPointerCheck.cpp
@@ -0,0 +1,80 @@
+//===--- DeleteNullPointerCheck.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 "DeleteNullPointerCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+void DeleteNullPointerCheck::registerMatchers(MatchFinder *Finder) {
+ const auto DeleteExpr =
+ cxxDeleteExpr(has(castExpr(has(declRefExpr(
+ to(decl(equalsBoundNode("deletedPointer"))))))))
+ .bind("deleteExpr");
+
+ const auto PointerCondition = castExpr(hasCastKind(CK_PointerToBoolean));
+ const auto BinaryPointerCheckCondition = binaryOperator(
+ allOf(hasEitherOperand(castExpr(hasCastKind(CK_NullToPointer))),
+ hasEitherOperand(ignoringImpCasts(declRefExpr()))));
+
+ Finder->addMatcher(
+ ifStmt(allOf(hasCondition(
+ anyOf(PointerCondition, BinaryPointerCheckCondition)),
+ hasCondition(anyOf(
+ ignoringImpCasts(
+ declRefExpr(to(decl().bind("deletedPointer")))),
+ binaryOperator(hasEitherOperand(ignoringImpCasts(
+ declRefExpr(to(decl().bind("deletedPointer")))))))),
+ hasThen(anyOf(
+ DeleteExpr,
+ compoundStmt(allOf(has(DeleteExpr), statementCountIs(1)))
+ .bind("compound")))))
+ .bind("ifWithDelete"),
+ this);
+}
+
+void DeleteNullPointerCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *IfWithDelete = Result.Nodes.getNodeAs<IfStmt>("ifWithDelete");
+ const auto *Compound = Result.Nodes.getNodeAs<CompoundStmt>("compound");
+
+ auto Diag = diag(
+ IfWithDelete->getLocStart(),
+ "'if' statement is unnecessary; deleting null pointer has no effect");
+ if (IfWithDelete->getElse()) {
+ return;
+ }
+
+ Diag << FixItHint::CreateRemoval(CharSourceRange::getTokenRange(
+ IfWithDelete->getLocStart(),
+ Lexer::getLocForEndOfToken(IfWithDelete->getCond()->getLocEnd(), 0,
+ *Result.SourceManager,
+ Result.Context->getLangOpts())));
+ if (Compound) {
+ Diag << FixItHint::CreateRemoval(CharSourceRange::getTokenRange(
+ Compound->getLBracLoc(),
+ Lexer::getLocForEndOfToken(Compound->getLBracLoc(), 0,
+ *Result.SourceManager,
+ Result.Context->getLangOpts())));
+ Diag << FixItHint::CreateRemoval(CharSourceRange::getTokenRange(
+ Compound->getRBracLoc(),
+ Lexer::getLocForEndOfToken(Compound->getRBracLoc(), 0,
+ *Result.SourceManager,
+ Result.Context->getLangOpts())));
+ }
+}
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/readability/CMakeLists.txt
===================================================================
--- clang-tidy/readability/CMakeLists.txt
+++ clang-tidy/readability/CMakeLists.txt
@@ -4,6 +4,7 @@
AvoidConstParamsInDecls.cpp
BracesAroundStatementsCheck.cpp
ContainerSizeEmptyCheck.cpp
+ DeleteNullPointerCheck.cpp
DeletedDefaultCheck.cpp
ElseAfterReturnCheck.cpp
FunctionSizeCheck.cpp
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