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 reworks constStatement to find more issues. It catches issue [8827](https://trac.cppcheck.net/ticket/8827):
```cpp
extern void foo(int,const char*,int);
void f(int value)
{
foo(42,"test",42),(value&42);
}
```
It also catches from issue [8451](https://trac.cppcheck.net/ticket/8451):
```cpp
void f1(int x) {
1;
(1);
(char)1;
((char)1);
!x;
(!x);
~x;
}
```
And also:
```cpp
void f(int x) {
x;
}
```
The other examples are not caught due to incomplete AST.
The unsigned less than zero checker looked for patterns like "<= 0".
Switching to use valueflow improves the checker in a few aspects.
First, it removes false positives where instead of 0, the code is using
0L, 0U, etc. Instead of having to hard code the different variants of 0,
valueflow handles this automatically. This fixes FPs on the form
uint32_t value = 0xFUL;
void f() {
if (value < 0u)
{
value = 0u;
}
}
where 0u was previously not recognized by the checker. This fixes#8836.
Morover, it makes it possible to handle templates properly. In commit
fa076598ade8a751ad85d5375bc976439e32c117, all warnings inside templates
were made inconclusive, since the checker had no idea if "0" came from
a template parameter or not.
This makes it possible to not warn for the following case which was
reported as a FP in #3233
template<int n> void foo(unsigned int x) {
if (x <= n);
}
foo<0>();
but give a warning for the following case
template<int n> void foo(unsigned int x) {
if (x <= 0);
}
Previously, both these cases gave inconclusive warnings.
Finally, it makes it possible to give warnings for the following code:
void f(unsigned x) {
int y = 0;
if (x <= y) {}
}
Also, previously, the checker for unsigned variables larger than 0, the
checker used the string of the astoperand. This meant that for code like
the following:
void f(unsigned x, unsigned y) {
if (x -y >= 0) {}
}
cppcheck would output
[unsigned-expression-positive.c] (style) Unsigned variable '-' can't be negative so it is unnecessary to test it.
using expressionString() instead gives a better error message
[unsigned-expression-positive.c] (style) Unsigned expression 'x-z' can't be negative so it is unnecessary to test it.
Add a check for function arguments that can be constant:
```cpp
extern void bar(int);
void f(int x) {
bar((x & 0x01) >> 7); // function 'bar' is always called with a '0'-argument
}
```
* Follow variables when comparing same expression
* Remove assert include
* Dont follow function arguments
* Improve the checking to check more cases
* Add more tests
* Check if the variable is used inside a loop
* Follow both variables
* Only skip loops when variable is modified in scope
* Fix FP when followed variable is modified
* Dont follow arrays
* Skip pointer indirection
* Make recursive
* Improve checking more variables
* Fix test with sizeof
* Skip following operators
* Fix test when using sizeof
* Dont check every step
* Use early returns
* Update test to use a loop instead of conditional
* Add static
* Check variables are global
* Check local variables in another scope
* Fix issue with const pointers
* Distinguish between pointer indirection and multiply
* Use simple match
* Prevent crash with uniform initialization
* Use unary op and ast to detect pointer indirection
* Expand error message when expression do not match exactly
* Add errorpath to issameexpression
* Revert "Clarify warning message for 'Same expression on both sides of operator'"
This reverts commit 0e491b41a8686a2b767ed1a116e6e3b6ff66f534.
* Check if the tokens are the same
* Report the operator and not the expressions
* Check for duplicate assignments
* Improve checking of expression
* Add more tests
* Use simple match
* Improve robustness of check
* check for null
* Reduce side effects by checking for side effects
* Improve verbose message
* Reword the error message
