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
* template simplifier: add 2 new template parameter simplifications
int{} -> 0
decltype(int{}) -> int
This fixes reduced test cases like #9153. I'm not sure they will help
real world code that much.
It was necessary to increase the pass count to 4 to get #9153 completly
simplified.
* relax decltype(type{}) simplification to any type
Refactored simplifyTemplateAliases to iterate over template type aliases
rather than instantiations. This fixed template type aliases that were
not templates.
Don't instantiate templates in template type aliases. They will get
instantiated once the type alias is instantiated. This required
increasing the template simplifier pass count to 3 so one of the
existing tests continued to work.
Specialized member classes declared outsize the class were not
recognized. This caused the the member class to be instantiated rather
than the specialized class. We already had a test for this but it was
wrong so it went unnoticed.
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;".
* template simplifier: fix instantiation of variadic template with no arguments
* fix white space change
* add support for <class...>
* add variadic template flag
* Fix issue 8890: AST broken calling member function from templated base class
* Format
* Check for double bracket
* Add test to createLinks2
* Remove extra test
* Reduce test case for links
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.
A common pattern is to have a function like similar to this:
bool isFlagSet(uint32_t f) {
return f & 0x4;
}
Warning that the function returns a non-boolean in this case is too
noisy, it would be better suited for a Misra check, so remove the
warnings in the most obvious cases.
Change the astStringVerbose() recursion to extend a string instead of
returning one. This has the benefit that for tokens where the recursion
runs deep (typically large arrays), the time savings can be substantial
(see comments on benchmarks further down).
The reason is that previously, for each token, the astString of its
operands was constructed, and then appended to this tokens astString.
This led to a lot of unnecessary string copying (and with that
allocations). Instead, by passing the string by reference, the number
of temporary strings is greatly reduced.
Another way of seeing it is that previously, the string was constructed
from end to beginning, but now it is constructed from the beginning to
end. There was no notable speedup by preallocating the entire string
using string::reserve() (at least not on Linux).
To benchmark, the changes and master were tested on Linux using the
commands:
make
time cppcheck --debug --verbose $file >/dev/null
i.e., the cppcheck binary was compiled with the settings in the
Makefile. Printing the output to screen or file will of course take
longer time.
In Trac ticket #8355 which triggered this change, an example file from the
Wine repository was attached. Running the above cppcheck on master took
24 minutes and with the changes in this commmit, took 22 seconds.
Another test made was on lib/tokenlist.cpp in the cppcheck repo, which is
more "normal" file. On that file there was no measurable time difference.
A synthetic benchmark was generated to illustrate the effects on dumping
the ast for arrays of different sizes. The generate code looked as
follows:
const int array[] = {...};
with different number of elements. The results are as follows (times are
in seconds):
N master optimized
10 0.1 0.1
100 0.1 0.1
1000 2.8 0.7
2000 19 1.8
3000 53 3.8
5000 350 10
10000 3215 38
As we can see, for small arrays, there is no time difference, but for
large arrays the time savings are substantial.
Rikard Falkeborn
Daniel Marjamäki
Ken-Patrick
Paul Fultz II
IOBYTE
orbitcowboy
Sebastian