https://bugs.llvm.org/show_bug.cgi?id=49174
Bug ID: 49174
Summary: c/c++ invalid -fsanitize=undefined crash with
"offsetof" like code
Product: clang
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: enhancement
Priority: P
Component: C
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected], [email protected],
[email protected], [email protected],
[email protected]
```
typedef struct type {
int member;
} type_t;
int main()
{
(char *)&((type_t *)(0))->member;
}
```
This crashes with:
```
temp.c:7:31: runtime error: member access within null pointer of type 'type_t'
(aka 'struct type')
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior temp.c:7:31 in
```
https://gcc.godbolt.org/z/dbWc6h
Note that the crash still occurs when using `((size_t)((char *)&((type_t
*)0)->member - (char *)0))`. See https://en.wikipedia.org/wiki/Offsetof for an
explanation of what is going on here.
The crash doesn't occur with `__builtin_offsetof`, so that is a viable work
around.
--
You are receiving this mail because:
You are on the CC list for the bug._______________________________________________
llvm-bugs mailing list
[email protected]
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
