* Set correct type and size of string and char literals
Use that string and char literal tokens store the prefix. This makes
it possible to distinghuish between different type of string literals
(i.e., utf8 encoded strings, utf16, wide strings, etc) which have
different type.
When the tokens holding the string and character values have the correct
type, it is possible to improve Token::getStrSize() to give the correct
result for all string types. Previously, it would return the number of
characters in the string, i.e., it would give the wrong size unless
the type of the string was char*.
Since strings now can have different size (in number of bytes) and
length (in number of elements), add a new helper function that returns
the number of characters. Checkers have been updated to use the correct
functions.
Having the size makes it possible to find more problems with prefixed
strings, and to reduce false positives, for example in the buffer
overflow checker.
Also, improve the stringLiteralWrite error message to also print the
prefix of the string (if there is one).
* Add comment and update string length
* Fix crashes in valueflow
http://cppcheck1.osuosl.org:8000/crash.html
For instance in http://cppcheck1.osuosl.org:8000/styx
```
==19651==ERROR: AddressSanitizer: SEGV on unknown address 0x00000000001c (pc 0x556f21abc3df bp 0x7ffc140d2720 sp 0x7ffc140d2710 T0)
==19651==The signal is caused by a READ memory access.
==19651==Hint: address points to the zero page.
#0 0x556f21abc3de in Variable::isGlobal() const ../lib/symboldatabase.h:342
#1 0x556f221f801a in valueFlowForwardVariable ../lib/valueflow.cpp:2471
#2 0x556f22208130 in valueFlowForward ../lib/valueflow.cpp:3204
#3 0x556f221e9e14 in valueFlowReverse ../lib/valueflow.cpp:1892
#4 0x556f221f1a43 in valueFlowBeforeCondition ../lib/valueflow.cpp:2200
#5 0x556f2223dbb5 in ValueFlow::setValues(TokenList*, SymbolDatabase*, ErrorLogger*, Settings const*) ../lib/valueflow.cpp:6521
#6 0x556f220e5991 in Tokenizer::simplifyTokens1(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) ../lib/tokenize.cpp:2342
#7 0x556f21d8d066 in CppCheck::checkFile(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::istream&) ../lib/cppcheck.cpp:508
#8 0x556f21d84cd3 in CppCheck::check(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) ../lib/cppcheck.cpp:192
#9 0x556f21a28796 in CppCheckExecutor::check_internal(CppCheck&, int, char const* const*) ../cli/cppcheckexecutor.cpp:884
#10 0x556f21a24be8 in CppCheckExecutor::check(int, char const* const*) ../cli/cppcheckexecutor.cpp:198
#11 0x556f22313063 in main ../cli/main.cpp:95
```
* Add test case for crash in valueflow
* Use lifetimes to check for returning reference to temporaries
* Check for dangling temporaries
* Check for unknown types for returining by reference
* Remove old returnTemporary check
* Format
* Check for deref op
* Ternary operator return an lvalue reference
* Warn when returning temporaries from member functions
* Improve handling of pointer to function
* Extend lifetimes of const references
* Add valueFlowForwardExpression function to forward values of an expression
* Use token for expression
* Fix name in bailout message
* Handle expressions
* Add more tests for more expressions
* Add more tests
* Solve the expression if possible
* Formatting
* Add impossible category
* Replace values
* Try to adjust known values
* Add ! for impossible values
* Add impossible with possible values
* Remove contradictions
* Add values when the branch is not dead
* Only copy possible values
* Dont bail on while loops
* Load std lib in valueflow
* Check for function calls
* Fix stl errors
* Fix incorrect impossible check
* Fix heap-after-use error
* Remove impossible values when they are lowered
* Show the bound and remove overlaps
* Infer conditions
* Dont push pointer values through dynamic_cast
* Add test for dynamic_cast issue
* Add shifttoomanybits test
* Add test for div by zero
* Add a test for issue 9315
* Dont make impossible value inconclusive
* Fix FP with shift operator
* Improve handleKnownValuesInLoop for impossible values
* Fix cppcheck warning
* Fix impossible values for ctu
* Bailout for streams
* Check equality conditions
* Fix overflows
* Add regression test for 9332
* Remove duplicate conditions
* Skip impossible values for invalid value
* Check for null
* Rename bound to range
* Formatting
This will now warn when doing something like this:
```cpp
template <class T, class K, class V>
const V& get_default(const T& t, const K& k, const V& v) {
auto it = t.find(k);
if (it == t.end()) return v;
return it->second;
}
const int& bar(const std::unordered_map<int, int>& m, int k) {
auto x = 0;
return get_default(m, k, x);
}
```
The lifetime warning is considered inconclusive in this case.
I also updated valueflow to no tinject inconclusive values unless `--inconclusive` flag is passed. This creates some false negatives because library functions are not configured to not modify their input parameters, and there are some checks that do not check if the value is inconclusive or not.
This fixes the issue by making `ProgramMemory` keep track of values based on the conditions.
It also removes the `deadpointer` check since it duplicates the `invalidLifetime` check.
* Try harder to track ref lifetimes
* Dont add lifetimes for references
* Use correct token
* Check for front and back as well
* Improve handling of addresses
* Formatting
* Fix FP
This fixes the FP in cases like this:
```cpp
void f() {
bool b;
bool * x = &b;
if (x != nullptr)
x = 1;
}
```
It tracks the indirection of the uninit value in valueflow.
