https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81598
Julien Blanc <julien.blanc at sprinte dot eu> changed:
What |Removed |Added
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CC| |julien.blanc at sprinte dot eu
--- Comment #9 from Julien Blanc <julien.blanc at sprinte dot eu> ---
I recently ran into this while trying to use -fsanitize=enum for the codebase.
The situation is worse for C++ enum class : since you can only assign them with
static_cast, no load check can be done (clang also fails to detect such cases).
Here’s a sample code that should trigger but does not :
#include <iostream>
enum class Foo
{
foo1 = 0,
foo2 = 1
};
std::ostream& operator<<(std::ostream& o, Foo foo)
{
switch(foo)
{
case Foo::foo1:
return o << "foo1";
case Foo::foo2:
return o << "foo2";
}
return o << "unknown";
}
int main()
{
Foo foo = static_cast<Foo>(3);
std::cout << foo << std::endl;
return 0;
}
$ g++ -fsanitize=enum -fsanitize=undefined -fno-sanitize-recover enum.cpp
$ ./a.out
unknown
$
Note that clang++ is no better :
$ clang++-7 -fsanitize=enum -fsanitize=undefined -fno-sanitize-recover=all
enum.cpp
$ ./a.out
unknown
$
But i’d expect both checkers to detect such misuse. While it could be valid
code, there’s a high chance that its a bug. Ideally an attribute could be used
if it is expected behaviour.
