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/* vi: set sw=4 ts=4: */
/*
* Trick to assign a const ptr with barrier for clang
*
* Copyright (C) 2021 by YU Jincheng <shana@zju.edu.cn>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
#if defined(__clang_major__) && __clang_major__ >= 9
/* Clang/llvm drops assignment to "constant" storage. Silently.
* Needs serious convincing to not eliminate the store.
*/
static ALWAYS_INLINE void* not_const_pp(const void *p)
{
void *pp;
asm volatile (
"# forget that p points to const"
: /*outputs*/ "=r" (pp)
: /*inputs*/ "0" (p)
);
return pp;
}
void FAST_FUNC ASSIGN_CONST_PTR(const void *pptr, void *v)
{
*(void**)not_const_pp(pptr) = v;
barrier();
}
void FAST_FUNC XZALLOC_CONST_PTR(const void *pptr, size_t size)
{
*(void**)not_const_pp(pptr) = xzalloc(size);
barrier();
}
#endif
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