New checker called bugprone-not-null-terminated-result. This checker finds
function calls where it is possible to cause a not null-terminated result.
Usually the proper length of a string is strlen(src) + 1 or equal length
of this expression, because the null terminator needs an extra space.
Without the null terminator it can result in undefined behaviour when the
string is read.
The following and their respective wchar_t based functions are checked:
memcpy, memcpy_s, memchr, memmove, memmove_s, strerror_s,
strncmp, strxfrm
The following is a real-world example where the programmer forgot to
increase the passed third argument, which is size_t length.
That is why the length of the allocated memory is not enough to hold the
null terminator.
static char *stringCpy(const std::string &str) {
char *result = reinterpret_cast<char *>(malloc(str.size()));
memcpy(result, str.data(), str.size());
return result;
}In addition to issuing warnings, fix-it rewrites all the necessary code.
It also tries to adjust the capacity of the destination array:
static char *stringCpy(const std::string &str) {
char *result = reinterpret_cast<char *>(malloc(str.size() + 1));
strcpy(result, str.data());
return result;
}Note: It cannot guarantee to rewrite every of the path-sensitive memory
allocations.
Binding names are copied/read a lot (for memoization purposes, see BoundNodesMap) during matching. It makes sense to make them shorter. Ideally they should fit into the inline std::string buffer (15 characters in libc++ on x86-64, https://gcc.godbolt.org/z/oNBghM).