danielmarjamaki updated this revision to Diff 96526.
danielmarjamaki added a comment.
Fixed review comments. Made code examples and documentation more motivational.
Repository:
rL LLVM
https://reviews.llvm.org/D32346
Files:
clang-tidy/readability/CMakeLists.txt
clang-tidy/readability/ReadabilityTidyModule.cpp
clang-tidy/readability/StrlenArgumentCheck.cpp
clang-tidy/readability/StrlenArgumentCheck.h
docs/ReleaseNotes.rst
docs/clang-tidy/checks/list.rst
docs/clang-tidy/checks/readability-strlen-argument.rst
test/clang-tidy/readability-strlen-argument.cpp
Index: test/clang-tidy/readability-strlen-argument.cpp
===================================================================
--- test/clang-tidy/readability-strlen-argument.cpp
+++ test/clang-tidy/readability-strlen-argument.cpp
@@ -0,0 +1,31 @@
+// RUN: %check_clang_tidy %s readability-strlen-argument %t
+
+namespace std {
+typedef __typeof(sizeof(int)) size_t;
+size_t strlen(const char *s);
+}; // namespace std
+using namespace std;
+
+void warn1(const char *Str) {
+ char *P;
+
+ // CHECK-MESSAGES: :[[@LINE+1]]:27: warning: strlen() argument has pointer addition, it is recommended to subtract the result instead. [readability-strlen-argument]
+ P = new char[strlen(Str + 1)];
+ // CHECK-FIXES: {{^}} P = new char[(strlen(Str) - 1)];{{$}}
+ delete[] P;
+
+ // CHECK-MESSAGES: :[[@LINE+1]]:30: warning: strlen() argument has pointer addition, it is recommended to subtract the result instead. [readability-strlen-argument]
+ P = new char[std::strlen(1 + Str)];
+ delete[] P;
+}
+
+struct S {
+ char *P;
+};
+void warn2(const struct S &Par) {
+ char *P;
+ // CHECK-MESSAGES: :[[@LINE+1]]:34: warning: strlen() argument has pointer addition, it is recommended to subtract the result instead. [readability-strlen-argument]
+ P = new char[std::strlen(Par.P + 1)];
+ // CHECK-FIXES: {{^}} P = new char[(std::strlen(Par.P) - 1)];{{$}}
+ delete[] P;
+}
Index: docs/clang-tidy/checks/readability-strlen-argument.rst
===================================================================
--- docs/clang-tidy/checks/readability-strlen-argument.rst
+++ docs/clang-tidy/checks/readability-strlen-argument.rst
@@ -0,0 +1,22 @@
+.. title:: clang-tidy - readability-strlen-argument
+
+readability-strlen-argument
+===========================
+
+This check will detect addition in `strlen()` argument.
+
+In the example code below the developer probably wanted to make room for an extra char in the allocation but misplaced the addition.
+
+.. code-block:: c++
+
+ char *p = new char[strlen(s + 1)];
+ strcpy(p, s);
+
+With -fix that becomes:
+
+.. code-block:: c++
+
+ char *p = new char[(strlen(s) - 1)]
+ strcpy(p, s);
+
+For readability it is considered better to subtract the result outside the `strlen()`.
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -169,4 +169,5 @@
readability-redundant-string-init
readability-simplify-boolean-expr
readability-static-definition-in-anonymous-namespace
+ readability-strlen-argument
readability-uniqueptr-delete-release
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -76,6 +76,12 @@
Finds functions that have more then `ParameterThreshold` parameters and emits a warning.
+- New `readability-strlen-argument
+ <http://clang.llvm.org/extra/clang-tidy/checks/readability-strlen-argument.html>`_ check
+
+ Finds misleading `strlen()` argument. If addition is used in the argument then the effect is that
+ the strlen() result is subtracted.
+
- New `hicpp` module
Adds checks that implement the `High Integrity C++ Coding Standard <http://www.codingstandard.com/section/index/>`_ and other safety
Index: clang-tidy/readability/StrlenArgumentCheck.h
===================================================================
--- clang-tidy/readability/StrlenArgumentCheck.h
+++ clang-tidy/readability/StrlenArgumentCheck.h
@@ -0,0 +1,35 @@
+//===--- StrlenArgumentCheck.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_STRLEN_ARGUMENT_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_STRLEN_ARGUMENT_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+/// Detect pointer addition in strlen() argument.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/readability-strlen-argument.html
+class StrlenArgumentCheck : public ClangTidyCheck {
+public:
+ StrlenArgumentCheck(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_STRLEN_ARGUMENT_H
Index: clang-tidy/readability/StrlenArgumentCheck.cpp
===================================================================
--- clang-tidy/readability/StrlenArgumentCheck.cpp
+++ clang-tidy/readability/StrlenArgumentCheck.cpp
@@ -0,0 +1,49 @@
+//===--- StrlenArgumentCheck.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 "StrlenArgumentCheck.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 StrlenArgumentCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(
+ callExpr(anyOf(callee(functionDecl(hasName("::strlen"))),
+ callee(functionDecl(hasName("std::strlen")))),
+ hasAnyArgument(ignoringParenImpCasts(
+ binaryOperator(hasOperatorName("+")).bind("B"))))
+ .bind("CE"),
+ this);
+}
+
+void StrlenArgumentCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *B = Result.Nodes.getNodeAs<BinaryOperator>("B");
+ const auto *CE = Result.Nodes.getNodeAs<CallExpr>("CE");
+ auto D =
+ diag(B->getExprLoc(), "strlen() argument has pointer addition, it is "
+ "recommended to subtract the result instead.");
+ if (!B->getRHS()->getType()->isAnyPointerType()) {
+ SourceLocation LHSEndLoc = Lexer::getLocForEndOfToken(
+ B->getLHS()->getLocEnd(), 0, *Result.SourceManager, getLangOpts());
+ D << FixItHint::CreateInsertion(LHSEndLoc, ")")
+ << FixItHint::CreateInsertion(CE->getLocStart(), "(")
+ << FixItHint::CreateReplacement(
+ SourceRange(B->getExprLoc(), B->getExprLoc()), "-");
+ }
+}
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/readability/ReadabilityTidyModule.cpp
===================================================================
--- clang-tidy/readability/ReadabilityTidyModule.cpp
+++ clang-tidy/readability/ReadabilityTidyModule.cpp
@@ -33,6 +33,7 @@
#include "RedundantStringInitCheck.h"
#include "SimplifyBooleanExprCheck.h"
#include "StaticDefinitionInAnonymousNamespaceCheck.h"
+#include "StrlenArgumentCheck.h"
#include "UniqueptrDeleteReleaseCheck.h"
namespace clang {
@@ -72,6 +73,8 @@
"readability-redundant-member-init");
CheckFactories.registerCheck<StaticDefinitionInAnonymousNamespaceCheck>(
"readability-static-definition-in-anonymous-namespace");
+ CheckFactories.registerCheck<StrlenArgumentCheck>(
+ "readability-strlen-argument");
CheckFactories.registerCheck<readability::NamedParameterCheck>(
"readability-named-parameter");
CheckFactories.registerCheck<NonConstParameterCheck>(
Index: clang-tidy/readability/CMakeLists.txt
===================================================================
--- clang-tidy/readability/CMakeLists.txt
+++ clang-tidy/readability/CMakeLists.txt
@@ -26,6 +26,7 @@
RedundantStringInitCheck.cpp
SimplifyBooleanExprCheck.cpp
StaticDefinitionInAnonymousNamespaceCheck.cpp
+ StrlenArgumentCheck.cpp
UniqueptrDeleteReleaseCheck.cpp
LINK_LIBS
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