https://bugs.llvm.org/show_bug.cgi?id=50322
Bug ID: 50322
Summary: inlines with names matching __builtin_* have entire
function body removed when calling builtin
Product: clang
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: enhancement
Priority: P
Component: -New Bugs
Assignee: unassignedclangb...@nondot.org
Reporter: keesc...@chromium.org
CC: htmldevelo...@gmail.com, llvm-bugs@lists.llvm.org,
neeil...@live.com, richard-l...@metafoo.co.uk
https://godbolt.org/z/fs9q55daM
typedef unsigned long size_t;
void fortify_panic(void) __attribute__((noreturn));
#ifndef USE_BUILTIN
extern void *memcpy_implementation(void *p, const void *q, size_t size);
#define __underlying_memcpy memcpy_implementation
#else
#define __underlying_memcpy __builtin_memcpy
#endif
// inlines with names matching a __builtin_* have their entire
// contents ignored when the matching __builtin is called anywhere
// in the function, regardless to conditionals or outcomes.
// If this isn't named "memcpy" or it doesn't ultimately call
// "__builtin_memcpy" it will work correctly.
inline void *memcpy(void *p, const void *q, size_t size)
{
size_t p_size = __builtin_object_size(p, 0);
if (p_size < size)
fortify_panic();
if (size > 4)
__underlying_memcpy(p, q, size);
return 0;
}
static char buf[8];
void *maybe_overflow(char *src, size_t size)
{
return memcpy(buf, src, size);
}
void *always_overflow(char *src)
{
return memcpy(buf, src, 16);
}
With -DUSE_BUILTIN all of the memcpy logic vanishes.
--
You are receiving this mail because:
You are on the CC list for the bug._______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
