[clang-tools-extra] r267011 - [clang-tidy] New checker to detect suspicious string constructor.
Etienne Bergeron via cfe-commits
cfe-commits at lists.llvm.org
Thu Apr 21 10:28:09 PDT 2016
Author: etienneb
Date: Thu Apr 21 12:28:08 2016
New Revision: 267011
URL: http://llvm.org/viewvc/llvm-project?rev=267011&view=rev
Log:
[clang-tidy] New checker to detect suspicious string constructor.
Summary:
Checker to validate string constructor parameters.
A common mistake is to swap parameter for the fill-constructor.
```
std::string str('x', 4);
std::string str('4', x);
```
Reviewers: alexfh
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D19146
Added:
clang-tools-extra/trunk/clang-tidy/misc/StringConstructorCheck.cpp
clang-tools-extra/trunk/clang-tidy/misc/StringConstructorCheck.h
clang-tools-extra/trunk/docs/clang-tidy/checks/misc-string-constructor.rst
clang-tools-extra/trunk/test/clang-tidy/misc-string-constructor.cpp
Modified:
clang-tools-extra/trunk/clang-tidy/misc/CMakeLists.txt
clang-tools-extra/trunk/clang-tidy/misc/MiscTidyModule.cpp
clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
Modified: clang-tools-extra/trunk/clang-tidy/misc/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/misc/CMakeLists.txt?rev=267011&r1=267010&r2=267011&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/misc/CMakeLists.txt (original)
+++ clang-tools-extra/trunk/clang-tidy/misc/CMakeLists.txt Thu Apr 21 12:28:08 2016
@@ -25,6 +25,7 @@ add_clang_library(clangTidyMiscModule
SizeofContainerCheck.cpp
SizeofExpressionCheck.cpp
StaticAssertCheck.cpp
+ StringConstructorCheck.cpp
StringIntegerAssignmentCheck.cpp
StringLiteralWithEmbeddedNulCheck.cpp
SuspiciousMissingCommaCheck.cpp
Modified: clang-tools-extra/trunk/clang-tidy/misc/MiscTidyModule.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/misc/MiscTidyModule.cpp?rev=267011&r1=267010&r2=267011&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/misc/MiscTidyModule.cpp (original)
+++ clang-tools-extra/trunk/clang-tidy/misc/MiscTidyModule.cpp Thu Apr 21 12:28:08 2016
@@ -33,6 +33,7 @@
#include "SizeofContainerCheck.h"
#include "SizeofExpressionCheck.h"
#include "StaticAssertCheck.h"
+#include "StringConstructorCheck.h"
#include "StringIntegerAssignmentCheck.h"
#include "StringLiteralWithEmbeddedNulCheck.h"
#include "SuspiciousMissingCommaCheck.h"
@@ -99,6 +100,8 @@ public:
"misc-sizeof-expression");
CheckFactories.registerCheck<StaticAssertCheck>(
"misc-static-assert");
+ CheckFactories.registerCheck<StringConstructorCheck>(
+ "misc-string-constructor");
CheckFactories.registerCheck<StringIntegerAssignmentCheck>(
"misc-string-integer-assignment");
CheckFactories.registerCheck<StringLiteralWithEmbeddedNulCheck>(
Added: clang-tools-extra/trunk/clang-tidy/misc/StringConstructorCheck.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/misc/StringConstructorCheck.cpp?rev=267011&view=auto
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/misc/StringConstructorCheck.cpp (added)
+++ clang-tools-extra/trunk/clang-tidy/misc/StringConstructorCheck.cpp Thu Apr 21 12:28:08 2016
@@ -0,0 +1,126 @@
+//===--- StringConstructorCheck.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 "StringConstructorCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+AST_MATCHER_P(IntegerLiteral, isBiggerThan, unsigned, N) {
+ return Node.getValue().getZExtValue() > N;
+}
+
+StringConstructorCheck::StringConstructorCheck(StringRef Name,
+ ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context),
+ WarnOnLargeLength(Options.get("WarnOnLargeLength", 1) != 0),
+ LargeLengthThreshold(Options.get("LargeLengthThreshold", 0x800000)) {}
+
+void StringConstructorCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
+ Options.store(Opts, "WarnOnLargeLength", WarnOnLargeLength);
+ Options.store(Opts, "LargeLengthThreshold", LargeLengthThreshold);
+}
+
+void StringConstructorCheck::registerMatchers(MatchFinder *Finder) {
+ if (!getLangOpts().CPlusPlus)
+ return;
+
+ const auto ZeroExpr = expr(ignoringParenImpCasts(integerLiteral(equals(0))));
+ const auto CharExpr = expr(ignoringParenImpCasts(characterLiteral()));
+ const auto NegativeExpr = expr(ignoringParenImpCasts(
+ unaryOperator(hasOperatorName("-"),
+ hasUnaryOperand(integerLiteral(unless(equals(0)))))));
+ const auto LargeLengthExpr = expr(ignoringParenImpCasts(
+ integerLiteral(isBiggerThan(LargeLengthThreshold))));
+ const auto CharPtrType = type(anyOf(pointerType(), arrayType()));
+
+ // Match a string-literal; even through a declaration with initializer.
+ const auto BoundStringLiteral = stringLiteral().bind("str");
+ const auto ConstStrLiteralDecl = varDecl(
+ isDefinition(), hasType(constantArrayType()), hasType(isConstQualified()),
+ hasInitializer(ignoringParenImpCasts(BoundStringLiteral)));
+ const auto ConstPtrStrLiteralDecl = varDecl(
+ isDefinition(),
+ hasType(pointerType(pointee(isAnyCharacter(), isConstQualified()))),
+ hasInitializer(ignoringParenImpCasts(BoundStringLiteral)));
+ auto ConstStrLiteral = expr(ignoringParenImpCasts(anyOf(
+ BoundStringLiteral, declRefExpr(hasDeclaration(anyOf(
+ ConstPtrStrLiteralDecl, ConstStrLiteralDecl))))));
+
+ // Check the fill constructor. Fills the string with n consecutive copies of
+ // character c. [i.e string(size_t n, char c);].
+ Finder->addMatcher(
+ cxxConstructExpr(
+ hasDeclaration(cxxMethodDecl(hasName("basic_string"))),
+ hasArgument(0, hasType(qualType(isInteger()))),
+ hasArgument(1, hasType(qualType(isInteger()))),
+ anyOf(
+ // Detect the expression: string('x', 40);
+ hasArgument(0, CharExpr.bind("swapped-parameter")),
+ // Detect the expression: string(0, ...);
+ hasArgument(0, ZeroExpr.bind("empty-string")),
+ // Detect the expression: string(-4, ...);
+ hasArgument(0, NegativeExpr.bind("negative-length")),
+ // Detect the expression: string(0x1234567, ...);
+ hasArgument(0, LargeLengthExpr.bind("large-length"))))
+ .bind("constructor"),
+ this);
+
+ // Check the literal string constructor with char pointer and length
+ // parameters. [i.e. string (const char* s, size_t n);]
+ Finder->addMatcher(
+ cxxConstructExpr(
+ hasDeclaration(cxxMethodDecl(hasName("basic_string"))),
+ hasArgument(0, hasType(CharPtrType)),
+ hasArgument(1, hasType(isInteger())),
+ anyOf(
+ // Detect the expression: string("...", 0);
+ hasArgument(1, ZeroExpr.bind("empty-string")),
+ // Detect the expression: string("...", -4);
+ hasArgument(1, NegativeExpr.bind("negative-length")),
+ // Detect the expression: string("lit", 0x1234567);
+ hasArgument(1, LargeLengthExpr.bind("large-length")),
+ // Detect the expression: string("lit", 5)
+ allOf(hasArgument(0, ConstStrLiteral.bind("literal-with-length")),
+ hasArgument(1, ignoringParenImpCasts(
+ integerLiteral().bind("int"))))))
+ .bind("constructor"),
+ this);
+}
+
+void StringConstructorCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *E = Result.Nodes.getNodeAs<Expr>("constructor");
+ SourceLocation Loc = E->getLocStart();
+
+ if (Result.Nodes.getNodeAs<Expr>("swapped-parameter")) {
+ diag(Loc, "constructor parameters are probably swapped");
+ } else if (Result.Nodes.getNodeAs<Expr>("empty-string")) {
+ diag(Loc, "constructor creating an empty string");
+ } else if (Result.Nodes.getNodeAs<Expr>("negative-length")) {
+ diag(Loc, "negative value used as length parameter");
+ } else if (Result.Nodes.getNodeAs<Expr>("large-length")) {
+ if (WarnOnLargeLength)
+ diag(Loc, "suspicious large length parameter");
+ } else if (Result.Nodes.getNodeAs<Expr>("literal-with-length")) {
+ const auto *Str = Result.Nodes.getNodeAs<StringLiteral>("str");
+ const auto *Lit = Result.Nodes.getNodeAs<IntegerLiteral>("int");
+ if (Lit->getValue().ugt(Str->getLength())) {
+ diag(Loc, "length is bigger then string literal size");
+ }
+ }
+}
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
Added: clang-tools-extra/trunk/clang-tidy/misc/StringConstructorCheck.h
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/misc/StringConstructorCheck.h?rev=267011&view=auto
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/misc/StringConstructorCheck.h (added)
+++ clang-tools-extra/trunk/clang-tidy/misc/StringConstructorCheck.h Thu Apr 21 12:28:08 2016
@@ -0,0 +1,39 @@
+//===--- StringConstructorCheck.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_STRING_CONSTRUCTOR_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_STRING_CONSTRUCTOR_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+/// Finds suspicious string constructor and check their parameters.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/misc-string-constructor.html
+class StringConstructorCheck : public ClangTidyCheck {
+public:
+ StringConstructorCheck(StringRef Name, ClangTidyContext *Context);
+ void storeOptions(ClangTidyOptions::OptionMap &Opts);
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+ const bool WarnOnLargeLength;
+ const unsigned int LargeLengthThreshold;
+};
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_STRING_CONSTRUCTOR_H
Modified: clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst?rev=267011&r1=267010&r2=267011&view=diff
==============================================================================
--- clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst (original)
+++ clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst Thu Apr 21 12:28:08 2016
@@ -69,6 +69,7 @@ Clang-Tidy Checks
misc-sizeof-container
misc-sizeof-expression
misc-static-assert
+ misc-string-constructor
misc-string-integer-assignment
misc-string-literal-with-embedded-nul
misc-suspicious-missing-comma
Added: clang-tools-extra/trunk/docs/clang-tidy/checks/misc-string-constructor.rst
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/clang-tidy/checks/misc-string-constructor.rst?rev=267011&view=auto
==============================================================================
--- clang-tools-extra/trunk/docs/clang-tidy/checks/misc-string-constructor.rst (added)
+++ clang-tools-extra/trunk/docs/clang-tidy/checks/misc-string-constructor.rst Thu Apr 21 12:28:08 2016
@@ -0,0 +1,36 @@
+.. title:: clang-tidy - misc-string-constructor
+
+misc-string-constructor
+=======================
+
+Finds string constructors that are suspicious and probably errors.
+
+
+A common mistake is to swap parameters to the 'fill' string-constructor.
+
+Examples:
+
+.. code:: c++
+
+ std::string('x', 50) str; // should be std::string(50, 'x')
+
+
+Calling the string-literal constructor with a length bigger than the literal is
+suspicious and adds extra random characters to the string.
+
+Examples:
+
+.. code:: c++
+
+ std::string("test", 200); // Will include random characters after "test".
+
+
+Creating an empty string from constructors with parameters is considered
+suspicious. The programmer should use the empty constructor instead.
+
+Examples:
+
+.. code:: c++
+
+ std::string("test", 0); // Creation of an empty string.
+
Added: clang-tools-extra/trunk/test/clang-tidy/misc-string-constructor.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/test/clang-tidy/misc-string-constructor.cpp?rev=267011&view=auto
==============================================================================
--- clang-tools-extra/trunk/test/clang-tidy/misc-string-constructor.cpp (added)
+++ clang-tools-extra/trunk/test/clang-tidy/misc-string-constructor.cpp Thu Apr 21 12:28:08 2016
@@ -0,0 +1,54 @@
+// RUN: %check_clang_tidy %s misc-string-constructor %t
+
+namespace std {
+template <typename T>
+class allocator {};
+template <typename T>
+class char_traits {};
+template <typename C, typename T = std::char_traits<C>, typename A = std::allocator<C> >
+struct basic_string {
+ basic_string();
+ basic_string(const C*, unsigned int size);
+ basic_string(unsigned int size, C c);
+};
+typedef basic_string<char> string;
+typedef basic_string<wchar_t> wstring;
+}
+
+const char* kText = "";
+const char kText2[] = "";
+extern const char kText3[];
+
+void Test() {
+ std::string str('x', 4);
+ // CHECK-MESSAGES: [[@LINE-1]]:15: warning: constructor parameters are probably swapped [misc-string-constructor]
+ std::wstring wstr(L'x', 4);
+ // CHECK-MESSAGES: [[@LINE-1]]:16: warning: constructor parameters are probably swapped
+ std::string s0(0, 'x');
+ // CHECK-MESSAGES: [[@LINE-1]]:15: warning: constructor creating an empty string
+ std::string s1(-4, 'x');
+ // CHECK-MESSAGES: [[@LINE-1]]:15: warning: negative value used as length parameter
+ std::string s2(0x1000000, 'x');
+ // CHECK-MESSAGES: [[@LINE-1]]:15: warning: suspicious large length parameter
+
+ std::string q0("test", 0);
+ // CHECK-MESSAGES: [[@LINE-1]]:15: warning: constructor creating an empty string
+ std::string q1(kText, -4);
+ // CHECK-MESSAGES: [[@LINE-1]]:15: warning: negative value used as length parameter
+ std::string q2("test", 200);
+ // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger then string literal size
+ std::string q3(kText, 200);
+ // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger then string literal size
+ std::string q4(kText2, 200);
+ // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger then string literal size
+ std::string q5(kText3, 0x1000000);
+ // CHECK-MESSAGES: [[@LINE-1]]:15: warning: suspicious large length parameter
+}
+
+void Valid() {
+ std::string empty();
+ std::string str(4, 'x');
+ std::wstring wstr(4, L'x');
+ std::string s1("test", 4);
+ std::string s2("test", 3);
+}
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