This fixes issue 8996 by improving the alias checking by using lifetime analysis. It also extends the lifetime checker to handle constructors and initializer lists for containers and arrays.
This uses the lifetime analysis to check when comparing pointer that point to different objects:
```cpp
int main(void)
{
int foo[10];
int bar[10];
int diff;
if(foo > bar) // Undefined Behavior
{
diff = 1;
}
return 0;
}
```
This will now warn for cases like this:
```cpp
auto& f() {
std::vector<int> x;
return x[0];
}
```
It also improves the handling of address of operator, so it can now warn across some function calls, like this:
```cpp
int& f(int& a) {
return a;
}
int* hello() {
int x = 0;
return &f(x);
}
```
This will use the lifetime checker for dangling references. It will find these cases for indirectly assigned reference:
```cpp
int &foo()
{
int s = 0;
int& x = s;
return x;
}
```
This will also fix issue 510 as well:
```cpp
int &f( int k )
{
static int &r = k;
return r;
}
```
This fixes valueflow to have a value for `||` operator here:
```cpp
bool f()
{
bool a = (4 == 3); // <-- 0
bool b = (3 == 3); // <-- 1
return a || b; // <-- 1
}
```
When comparing if the shift is large enough to make the result zero, use
an unsigned long long to make sure the result fits. Also, a check that
avoids setting the value if the shift is equal to or larger than the
number of bits in the operand (this is undefined behaviour). Finally,
add a check to make sure the calculated value is not too large to store.
Add test cases to cover this.
This was detected by an MSVC warning.
valueflow.cpp(1350): warning C4334: '<<' : result of 32-bit shift implicitly
converted to 64 bits (was 64-bit shift intended?)
* valueflow: remove unused variable known
since e4677ae640 will trigger :
lib/valueflow.cpp:506:20: warning: unused variable 'known' [-Wunused-variable]
const bool known = (parent->astOperand1()->hasKnownValue() ||
* templatesimplifier: cleanup
since 48c960f56c showing:
lib/templatesimplifier.h:279:16: warning: private field 'mTokenizer' is not used
[-Wunused-private-field]
Tokenizer *mTokenizer;
This fixes issue in:
```cpp
void f()
{
char stack[512];
RGNDATA *data;
if (data_size > sizeof (stack))
data = malloc (data_size);
else
data = (RGNDATA *)stack;
if ((char *)data != stack)
free (data); // <- data is not stack
}
```
It seems the `ProgramMemory` can't handle two known values(such as int and tok) together. So instead `ValueFlowAfterAssign` runs `ValueFlowForward` with tok values and then runs it with the other values.
This makes arrays non-null in valueflow, so it can catch comparisons against null that is always true:
```cpp
void f(void) {
int buf[42];
if( buf != 0) {;} // << always true
}
```
So this unifies the `valueFlowAfterCondition` so it re-uses more code between checking for integers and container sizes. This should make valueFlowContainer more robust.
It also extends valueflow to support container comparisons such as `if (v.size() < 3)` or `if (v.size() > 3)` using the same mechanism that is used for integers.
This fixes several FPs in the lifetime checker. It also fixes issue [8846](https://trac.cppcheck.net/ticket/8846):
```cpp
int * f(int a[])
{
return a;
}
```
* Use lifetime analysis for pointers as well
* Fix issue 1143: Pointer to local array
* Update message when using pointers
* Avoid infinite loop in tracing lifetimes
* Inital valueflow lifetime checker
* Forward values
* Add initial tests
* Fix deplicate messages
* Fix traversing nested lambdas
* Turn test case into a todo
* Skip if returning a container
* Fix FP when using references
* Add missing header
* Fix FP from broken scopes
* Fix FP with static variable
* Add test for more FPs
* Parse lambda functions
* Check for capture by value
* Add tests for using a container and lambda together
* Fix cppcheck errors
* Add test for nextAfterAstRightmostLeaf
* Add valueflow tests
* Update error message
* Check for correct lambda token
* Improve error path reporting
* Fix hang when parsing arrays that look almlost like lambdas
* Add valueflow for terminating conditions
* Add valueflow test
* Dont check for same expressions for now to avoid double diagnostics
* Check nesting
* Add more tests
* Ensure conditions happen in order
* Check for null
* Add error path
* Support same expression check as well
* Use early continue
* Skip checking the same token
* Avoid double condtion diagnosis
* Fix FP when in switch statements
* Fix FP when time function
* Skip conditional escapes
* Use simpleMatch
* Fix naming
* Fix typo
Paul Fultz II
Daniel Marjamäki
rikardfalkeborn
practicalswift
Carlo Marcelo Arenas Belón
Igor
orbitcowboy