Typically with
```
int F(int *f);
void F2(int *a, int *b) {
int c = *a;
F(a); // modifies *a
if (b && c != *a) {}
}
```
we would get the following FP:
```
[test.cpp:3] -> [test.cpp:5]: (style) The comparison 'c != *a' is always false because 'c' and '*a' represent the same value.\n
```
I guess it boils down to isSameExpression only checking that the
expression is the same (in the above case, "*a" and "*a" are indeed the
same), but there's not real check on the values.
So the patch here is a bit hackish, and we still have false negatives in
cases with dereferenced pointers.
* Refactor isNullOperand out of FwdAnalysis
* Improve isNullOperand
* Fix redundantAssignment FP with unsigned zero
* isNullValue check number
* Enhance isNullOperand to handle c++ casts
Also handle cast of NULL.
* Add cases for 9356
* 9356: Prevent false positive when passing non-const reference to member constructor
This workarounds false positives 'Parameter can be declared with const [constParameter]'
when said parameter is used in constructor call. It assume the
constructor call might change the parameter (without any checks.
The drawback is that we have false negative, in cases where we could
check the constructor actually takes a const reference, or a copied by
value parameter.
* Add todo comment in isVariableMutableInInitializer
* cppcheck.cpp: Check for JSON error when parsing addon .json files
This fixes that errors in JSON files given via `--addon=*.json` are
silently ignored and maybe only a part of the JSON file is used.
Now the error message which picojson can return is checked and a
corresponding error message is returned again by getAddonInfo().
* naming.json: Fix missing comma
* CLI: Fix naming violations detected by addon naming.py via naming.json
* Addon naming: Add argument for validating names of constants
* LIB: Rename functions/variables so they are valid, loosen naming rules
* GUI: Fix naming violations
Previously, cppcheck discarded the `extern "C"` specifier. This patch modifies cppcheck to parse each as a Scope in the symbol database, then uses that scope to avoid false positives when making recommendations about changing a function argument to be a reference (since variable references is a C++ feature, unavailable in C, and thus unavailable in `extern "C"`).
* make ellipsis ... a single token
Using cppcheck -E to preprocess code with ellipsis produces output that
can't be compiled because ... is split into 3 tokens.
* try to fix addon
* Update symbol database such that the override keyword implies that the function is also virtual
* Add test case for implicit override
* change isVirtual to hasVirtualSpecifier
* fix method documentation for getVirtualFunctionCalls and getFirstVirtualFunctionCallStack
* Fix isImplicitlyVirtual to consider the override keyword and document logic
* Fix getFirstVirtualFunctionCallStack and getVirtualFunctionCalls to use isImplicitlyVirtual instead of isVirtual so new test case passes
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
fa076598ad, 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
}
```
The while part of a do-while loop looks almost like a function call, so
extend the check for function calls to ignore while-statements.
Note that there was only an FP when checking c-code, since the check is
disabled for c++-code. Therefore, make sure the test cases are run on a
c-file.
* 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 0e491b41a8.
* Check if the tokens are the same
* Report the operator and not the expressions
Paul Fultz II
Daniel Marjamäki
Oliver Stöneberg
shaneasd
Kamil Dudka
Ken-Patrick Lehrmann
miltolstoy
Rikard Falkeborn
Dmitry-Me
Sebastian
Steve Mokris
warmsocks
IOBYTE
Carlo Marcelo Arenas Belon
lordylike