* Tokenize: Set varId for variables in enum
Set varIds in enum values. It was previously disabled in 5119ae84b8
to avoid issues with enums named the same as global variables. Take care
to only set varids to variables used to set the value of an enumerator,
not the enumerator itself. This is somewhat complicated by the fact that
at the time this happens, astOperand1(), astOperand2(), astParent() etc
are not set. The current implementation is not perfect, for example in
the code below, y will not have a varid set, but x and z will. This is
deemed sufficient for now.
int x, y, z;
enum E { a = f(x, y, z); };
* Fix#9647: Value of enums with variables as init values
C++ allows enum values to be set using constexprs, which cppcheck did
not handle before. To solve this, add a new pass to valueflow to update
enum values after global consts have been processed. In order to do so,
I moved all settings of enum values to valueflow. After setting the enum
values, we need another call to valueFlowNumber() to actually set users
of the enums.
There is still room for improvements, since each pass of
valueFlowGlobalConstVar() and valueFlowEnumValue() only sets variables
that are possible to set directly, and not if setting the value of a
variable allows us to set the value of another. For example
constexpr int a = 5;
constexpr int b = a + 5;
enum E { X = a };
constexpr E e = X;
Here both b and e will not have their values set, even though cppcheck
should be possible to figure out their values. That's for another PR
though.
This was tested by running test-my-pr.py with 500 packages. The only
difference was one error message in fairy-stockfish_11.1, where cppcheck
now printed the correct size of an array instead of 2147483648 which I
assume is some kind of default value. In that package, using a constexpr
when setting enum values is common, but as mentioned, there was no
change in the number of warnings.
The value of something in the middle of a condition with mixed || and &&
gives no information on which branch will be taken.
For instance with:
```
int f(int a, int b, bool x) {\n"
if (a == 1 && (!(b == 2 && x))) {
} else {
if (x) {
}
}
return 0;
}
```
We can enter the if part whether x is true or false, and similarly,
enter the else part whether x is true or false. Same thing with the
value of b.
This fixes the following false positive with above code:
```
:4:13: style: Condition 'x' is always true [knownConditionTrueFalse]
if (x) {
^
:2:33: note: Assuming that condition 'x' is not redundant
if (a == 6 && (!(b == 21 && x))) {
^
```
This fixes issues (at least false positives) in code using them.
For instance:
```
unsigned compute(unsigned long long a) {
unsigned num = 0;
while (a > 0xFFFFFFFF) {
a >>= 32;
num += 32;
}
if (a > 0xFFFF) {
a >>= 16;
num += 16;
}
if (a > 0xFF) {
num += 8;
}
return num;
}
```
would give false positive:
```
cppcheck --enable=style sl3.cpp
Checking sl3.cpp ...
sl3.cpp:11:11: style: Condition 'a>0xFF' is always false [knownConditionTrueFalse]
if (a > 0xFF) {
^
sl3.cpp:3:14: note: Assuming that condition 'a>0xFFFFFFFF' is not redundant
while (a > 0xFFFFFFFF) {
^
sl3.cpp:11:11: note: Condition 'a>0xFF' is always false
if (a > 0xFF) {
^
```
In some cases, the condition of the ternary operator is assigned a known
value after the two possible results, and in such cases, we would not
take the opportunity to assign a value to the ternary operator (and to
the other parents in the ast).
This patch adds this capability.
- Remove errorPath of a value on assignment (this fixes enormous memory consumption for code with many subsequent assignments)
- De-virtualized a simple get function that was virtual for no reason
- Cloned function isAliasOf() for single values to avoid instantiating unnecessary std::list objects (
- Replaced a couple of trivial Token::Match/simpleMatch expressions by direct comparison
- Treat enumerators as literal values
Comparing before and after (Ir per call) when scanning the Cppcheck source:
SingleValueFlowForwardAnalyzer.isAlias()
1246 -> 1101
MultiValueFlowForwardAnalyzer.isAlias()
4202 -> 1617
Ensure bifurcate() does not recurse endlessly where a variable is
initialized recursively, or a variable is initialized as x(0) or x{0}
followed by a recursive assignment (for example int x(0); x = x / 1;).
The first case is solved by bailing out if there initialization is done
using x(0) or x{0}, the second by adding a missing depth argument to a
recursive call.
* Set bounds when combining values
* Adust bounds when they are negated
* Try to infer conditional values
* Switch false and true
* Fix checking of conditions
* Fix compare
* Fix remaining tests
* Fix overflows
* Add indirect to library cfg files
* Check indirect for non null arguments
* Reenable subfunction analysis
* Use indirect 1 when using not-null
* Parse correct string name
* Update documentation
* Make attribute optional
* Fix issue 9404: False positive: Either the condition 'if(x)' is redundant or there is possible null pointer dereference: a->x
* Use simpleMatch
* Add a test case for the FP
* Check if expression is changed
* Check for no return scope
* Use simpleMatch
* Traverse conditions for container size
* Move program memory to seperate file
* Revert "Traverse conditions for container size"
This reverts commit 914783769f.
* Move pathanalysis to seperate files
* 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.
This will diagnose more issues such as:
```cpp
void f(std::vector<int> &v) {
auto v0 = v.begin();
v.push_back(123);
std::cout << *v0 << std::endl;
}
```
This switches to use lifetime analysis to check for assigning to non-local variables:
```cpp
class test
{
public:
void f()
{
int x;
this->ptr = &x;
}
protected:
int *ptr;
};
```
* Allow to configure realloc like functions
* memleakonrealloc: Bring back tests.
The old memleak checker was removed, and the tests for it was removed in
commit 9765a2dfab. This also removed the
tests for memleakOnRealloc. Bring back those tests, somewhat modified
since the checker no longer checks for memory leaks.
* Add realloc to mem leak check
* Add tests of realloc buffer size
* Configure realloc functions
* Add test of freopen
* Allow to configure which element is realloc argument
* Fix wrong close in test
cppcheck now warns for this
* Update manual
* Update docs
* Rename alloc/dalloc/realloc functions
Naming the member function realloc caused problems on appveyor. Rename
the alloc and dealloc functions as well for consistency.
* Change comparisson order
* Remove variable and use function call directly
* Create temporary variable to simplify
* Throw mismatchError on mismatching allocation/reallocation
* Refactor to separate function
* Fix potential nullptr dereference
As pointed out by cppcheck.
* 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
Building with enhanced clang warnings indicated a large number of
instances with the warning:
`warning: zero as null pointer constant`
Recommended practice in C++11 is to use `nullptr` as value for
a NULL or empty pointer value. All instances where this warning
was encountered were corrected in this commit.
Where warning was encountered in dependency code (i.e. external library)
no chnages were made. Patching will be offered upstream.
strdup() allocates the string length plus one for a terminating null
character. Add one to compensate for this.
Fixes false positive buffer out of bounds on code like this:
void f() {
const char *a = "abcd";
char * b = strdup(a);
printf("%c", b[4]); // prints the terminating null character
free(b);
}
Also, add a testcase for valueFlowDynamicBufferSize() and add tests for
strdup(), malloc() and calloc().
* Add non const version of some methods of Token
The aim is to reduce the (ab)use of const_cast.
* Cleanup some more const_cast in valueflow
* Remove useless const_cast
* Remove some const_cast from templatesimplifier
* Remove some const_cast from valueflow
With the following code
int f(int x, int y) {
if (!!(x != 0)) {
return y/x;
}
cppcheck would wrongly warn that there might be a division by zero in
"return y/x;".
* build: remove -Wabi and add -Wundef
gcc >= 8 throws a warning about -Wabi (without a specific ABI version)
being ignored, while -Wundef seems more useful (as shown by the change
in config.h, which was probably an unfortunate typo)
travis.yaml should probably be updated soon, but was left out from this
change as the current images don't yet need it
* lib: unused function in valueflow
refactored out since 8c03be3212
lib/valueflow.cpp:3124:21: warning: unused function 'endTemplateArgument' [-Wunused-function]
* readme: include picojson
* make: also clean exe
This will warn for cases where searching in an associative container happens before insertion, like this:
```cpp
void f1(std::set<unsigned>& s, unsigned x) {
if (s.find(x) == s.end()) {
s.insert(x);
}
}
void f2(std::map<unsigned, unsigned>& m, unsigned x) {
if (m.find(x) == m.end()) {
m.emplace(x, 1);
} else {
m[x] = 1;
}
}
```
In the case of the map it could be written as `m[x] = 1` as it will create the key if it doesnt exist, so the extra search is not necessary.
I have this marked as `performance` as it is mostly concerning performance, but there could be a copy-paste error possibly, although I dont think thats common.
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;
}
```
IOBYTE
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