f57f90dfd1
This checker checks copy and move assignment operators whether they are protected against self-assignment. Since C++ core guidelines discourages explicit checking for `&rhs==this` in general we take a different approach: in top-frame analysis we branch the exploded graph for two cases, where &rhs==this and &rhs!=this and let existing checkers (e.g. unix.Malloc) do the rest of the work. It is important that we check all copy and move assignment operator in top frame even if we checked them already since self-assignments may happen undetected even in the same translation unit (e.g. using random indices for an array what may or may not be the same). This reapplies r275820 after fixing a string-lifetime issue discovered by the bots. A patch by Ádám Balogh! Differential Revision: https://reviews.llvm.org/D19311 llvm-svn: 276365
90 lines
3.2 KiB
C++
90 lines
3.2 KiB
C++
// RUN: %clang_cc1 -std=c++11 -analyze -analyzer-checker=core,cplusplus,unix.Malloc,debug.ExprInspection %s -verify -analyzer-output=text
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extern "C" char *strdup(const char* s);
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extern "C" void free(void* ptr);
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namespace std {
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template<class T> struct remove_reference { typedef T type; };
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template<class T> struct remove_reference<T&> { typedef T type; };
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template<class T> struct remove_reference<T&&> { typedef T type; };
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template<class T> typename remove_reference<T>::type&& move(T&& t);
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}
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void clang_analyzer_eval(int);
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class StringUsed {
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public:
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StringUsed(const char *s = "") : str(strdup(s)) {}
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StringUsed(const StringUsed &rhs) : str(strdup(rhs.str)) {}
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~StringUsed();
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StringUsed& operator=(const StringUsed &rhs);
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StringUsed& operator=(StringUsed &&rhs);
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operator const char*() const;
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private:
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char *str;
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};
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StringUsed::~StringUsed() {
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free(str);
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}
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StringUsed& StringUsed::operator=(const StringUsed &rhs) { // expected-note{{Assuming rhs == *this}} expected-note{{Assuming rhs == *this}} expected-note{{Assuming rhs != *this}}
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clang_analyzer_eval(*this == rhs); // expected-warning{{TRUE}} expected-warning{{UNKNOWN}} expected-note{{TRUE}} expected-note{{UNKNOWN}}
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free(str); // expected-note{{Memory is released}}
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str = strdup(rhs.str); // expected-warning{{Use of memory after it is freed}} expected-note{{Use of memory after it is freed}}
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return *this;
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}
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StringUsed& StringUsed::operator=(StringUsed &&rhs) { // expected-note{{Assuming rhs == *this}} expected-note{{Assuming rhs != *this}}
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clang_analyzer_eval(*this == rhs); // expected-warning{{TRUE}} expected-warning{{UNKNOWN}} expected-note{{TRUE}} expected-note{{UNKNOWN}}
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str = rhs.str;
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rhs.str = nullptr; // FIXME: An improved leak checker should warn here
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return *this;
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}
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StringUsed::operator const char*() const {
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return str;
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}
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class StringUnused {
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public:
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StringUnused(const char *s = "") : str(strdup(s)) {}
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StringUnused(const StringUnused &rhs) : str(strdup(rhs.str)) {}
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~StringUnused();
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StringUnused& operator=(const StringUnused &rhs);
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StringUnused& operator=(StringUnused &&rhs);
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operator const char*() const;
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private:
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char *str;
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};
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StringUnused::~StringUnused() {
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free(str);
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}
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StringUnused& StringUnused::operator=(const StringUnused &rhs) { // expected-note{{Assuming rhs == *this}} expected-note{{Assuming rhs == *this}} expected-note{{Assuming rhs != *this}}
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clang_analyzer_eval(*this == rhs); // expected-warning{{TRUE}} expected-warning{{UNKNOWN}} expected-note{{TRUE}} expected-note{{UNKNOWN}}
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free(str); // expected-note{{Memory is released}}
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str = strdup(rhs.str); // expected-warning{{Use of memory after it is freed}} expected-note{{Use of memory after it is freed}}
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return *this;
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}
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StringUnused& StringUnused::operator=(StringUnused &&rhs) { // expected-note{{Assuming rhs == *this}} expected-note{{Assuming rhs != *this}}
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clang_analyzer_eval(*this == rhs); // expected-warning{{TRUE}} expected-warning{{UNKNOWN}} expected-note{{TRUE}} expected-note{{UNKNOWN}}
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str = rhs.str;
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rhs.str = nullptr; // FIXME: An improved leak checker should warn here
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return *this;
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}
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StringUnused::operator const char*() const {
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return str;
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}
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int main() {
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StringUsed s1 ("test"), s2;
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s2 = s1;
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s2 = std::move(s1);
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return 0;
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}
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