Clang UBSAN 报告类型 'std::_Ios_Fmtflags' 的无效值
Clang++ UBSAN reports invalid value fro type 'std::_Ios_Fmtflags'
以下代码用clang UBSAN编译会崩溃
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <sstream>
template<class T>
inline std::string floatToString(T i){
printf("in floatToString\n");
std::stringstream ss;
ss.precision(6);
ss << std::noshowpoint << i;
printf("exit floatToString\n");
return ss.str();
}
int main() {
std::cout << floatToString(1.0) << "\n";
return 0;
}
使用 Clang 3.6 编译:
$> clang++-3.6 -fsanitize=undefined -fno-sanitize=float-divide-by-zero,vptr,function -fno-sanitize-recover -o test test.cpp
然后程序崩溃了:
$> ./test
in floatToString
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/ios_base.h:96:24: runtime error: load of value 4294966271, which is not a valid value for type 'std::_Ios_Fmtflags'
有人可以帮助解释为什么当我打开 clang UBSAN 时会出现这个问题吗?
根据 http://lists.cs.uiuc.edu/pipermail/cfe-dev/2013-January/027401.html,这是 libstdc++ 中的错误。
仍然存在于 libstdc++ 5.1 中。
libc++ 按预期工作:
$ clang++ -stdlib=libc++ -fsanitize=undefined -fno-sanitize=float-divide-by-zero,vptr,function -fno-sanitize-recover -o test test.cpp -lc++abi
$ ./test
in floatToString
exit floatToString
1
以下代码用clang UBSAN编译会崩溃
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <sstream>
template<class T>
inline std::string floatToString(T i){
printf("in floatToString\n");
std::stringstream ss;
ss.precision(6);
ss << std::noshowpoint << i;
printf("exit floatToString\n");
return ss.str();
}
int main() {
std::cout << floatToString(1.0) << "\n";
return 0;
}
使用 Clang 3.6 编译:
$> clang++-3.6 -fsanitize=undefined -fno-sanitize=float-divide-by-zero,vptr,function -fno-sanitize-recover -o test test.cpp
然后程序崩溃了:
$> ./test in floatToString /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/ios_base.h:96:24: runtime error: load of value 4294966271, which is not a valid value for type 'std::_Ios_Fmtflags'
有人可以帮助解释为什么当我打开 clang UBSAN 时会出现这个问题吗?
根据 http://lists.cs.uiuc.edu/pipermail/cfe-dev/2013-January/027401.html,这是 libstdc++ 中的错误。
仍然存在于 libstdc++ 5.1 中。
libc++ 按预期工作:
$ clang++ -stdlib=libc++ -fsanitize=undefined -fno-sanitize=float-divide-by-zero,vptr,function -fno-sanitize-recover -o test test.cpp -lc++abi
$ ./test
in floatToString
exit floatToString
1