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244f5c4795
It was observed that getty crashes on RISC-V 64-bit target, with the
busybox binary compiled by clang/LLVM 17 with -O2. Not only getty,
but also some other applets like syslogd/vi are broken too.
Commit 5156b245 ("Make const ptr assign as function call in clang")
introduced XZALLOC_CONST_PTR() to defeat the compiler optimization,
however it only fixed a small number of broken places when compiling
busybox with clang/LLVM. A large number of places remain broken.
This commit treats ASSIGN_CONST_PTR() the same way as XZALLOC_CONST_PTR().
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
35 lines
846 B
C
35 lines
846 B
C
/* vi: set sw=4 ts=4: */
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/*
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* Trick to assign a const ptr with barrier for clang
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*
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* Copyright (C) 2021 by YU Jincheng <shana@zju.edu.cn>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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#include "libbb.h"
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#if defined(__clang_major__) && __clang_major__ >= 9
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/* Clang/llvm drops assignment to "constant" storage. Silently.
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* Needs serious convincing to not eliminate the store.
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*/
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static ALWAYS_INLINE void* not_const_pp(const void *p)
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{
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void *pp;
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asm volatile (
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"# forget that p points to const"
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: /*outputs*/ "=r" (pp)
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: /*inputs*/ "0" (p)
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);
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return pp;
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}
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void FAST_FUNC ASSIGN_CONST_PTR(const void *pptr, void *v)
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{
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*(void**)not_const_pp(pptr) = v;
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barrier();
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}
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void FAST_FUNC XZALLOC_CONST_PTR(const void *pptr, size_t size)
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{
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*(void**)not_const_pp(pptr) = xzalloc(size);
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barrier();
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}
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#endif
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