ff8076d75a
zeroptr is a linker object pointing at 0 that can be used to thwart GCC's (and other compilers') "dereferencing NULL is undefined" optimization strategy when it gets in the way. Change-Id: I6aa6f28283281ebae73d6349811e290bf1b99483 Signed-off-by: Patrick Georgi <patrick@georgi-clan.de> Reviewed-on: https://review.coreboot.org/12294 Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com> Tested-by: build bot (Jenkins) Reviewed-by: Martin Roth <martinroth@google.com>
45 lines
1 KiB
C
45 lines
1 KiB
C
#ifndef STDDEF_H
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#define STDDEF_H
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#include <commonlib/helpers.h>
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typedef long ptrdiff_t;
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#ifndef __SIZE_TYPE__
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#define __SIZE_TYPE__ unsigned long
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#endif
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typedef __SIZE_TYPE__ size_t;
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/* There is a GCC macro for a size_t type, but not
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* for a ssize_t type. Below construct tricks GCC
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* into making __SIZE_TYPE__ signed.
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*/
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#define unsigned signed
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typedef __SIZE_TYPE__ ssize_t;
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#undef unsigned
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typedef int wchar_t;
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typedef unsigned int wint_t;
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#define NULL ((void *)0)
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#ifdef __PRE_RAM__
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#define ROMSTAGE_CONST const
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#else
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#define ROMSTAGE_CONST
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#endif
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/* Work around non-writable data segment in execute-in-place romstage on x86. */
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#if defined(__PRE_RAM__) && CONFIG_ARCH_X86
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#define MAYBE_STATIC
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#else
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#define MAYBE_STATIC static
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#endif
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#ifndef __ROMCC__
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/* Provide a pointer to address 0 that thwarts any "accessing this is
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* undefined behaviour and do whatever" trickery in compilers.
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* Use when you _really_ need to read32(zeroptr) (ie. read address 0).
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*/
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extern void *zeroptr;
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#endif
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#endif /* STDDEF_H */
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