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libctf, elfcpp, gold: do not assume that <byteswap.h> contains bswap_*

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At least one C library (uclibc-ng) defines some of these only when
the compiler is GCC.  We might as well test for all three cases and
handle any of them being missing.

Very similar code exists in libctf and split between elfcpp and gold:
fix both.

(Also sync up elfcpp with a change made to libctf swap.h a few months
ago: since there is no out-of-line definition of the bswap replacements,
they should be declared static inline, not just inline, to prevent the
linker generating out-of-line references to them.)

	PR libctf/25120
libctf/
	* configure.ac: Check for bswap_16, bswap_32, and bswap_64 decls.
	* swap.h (bswap_16): Do not assume that presence of <byteswap.h>
	means this is declared.
	(bswap_32): Likewise.
	(bswap_64): Likewise.
	(bswap_identity_64): Remove, unused.
	* configure: Regenerated.
	* config.h.in: Likewise.
gold/
	* configure.ac: Check for bswap_16, bswap_32, and bswap_64 decls.
	* configure: Regenerated.
	* config.h.in: Likewise.
elfcpp/
	* elfcpp_swap.h (bswap_16): Do not assume that presence of
	<byteswap.h> means this is declared.  Make static inline, matching
	recent change to libctf, since there is no non-inline definition
	of these functions.
	(bswap_32): Likewise.
	(bswap_64): Likewise.
This commit is contained in:
Nick Alcock 2019-12-13 15:19:17 +00:00
parent 866706584c
commit e755667f94
11 changed files with 190 additions and 59 deletions
Download patch file Download diff file Expand all files Collapse all files

16
elfcpp/elfcpp_swap.h
View file

@ -46,15 +46,19 @@
#ifdef HAVE_BYTESWAP_H
#include <byteswap.h>
#else
#endif // defined(HAVE_BYTESWAP_H)
// Provide our own versions of the byteswap functions.
inline uint16_t
#if !HAVE_DECL_BSWAP_16
static inline uint16_t
bswap_16(uint16_t v)
{
return ((v >> 8) & 0xff) | ((v & 0xff) << 8);
}
#endif // !HAVE_DECL_BSWAP16
inline uint32_t
#if !HAVE_DECL_BSWAP_32
static inline uint32_t
bswap_32(uint32_t v)
{
return ( ((v & 0xff000000) >> 24)
@ -62,8 +66,10 @@ bswap_32(uint32_t v)
| ((v & 0x0000ff00) << 8)
| ((v & 0x000000ff) << 24));
}
#endif // !HAVE_DECL_BSWAP32
inline uint64_t
#if !HAVE_DECL_BSWAP_64
static inline uint64_t
bswap_64(uint64_t v)
{
return ( ((v & 0xff00000000000000ULL) >> 56)
@ -75,7 +81,7 @@ bswap_64(uint64_t v)
| ((v & 0x000000000000ff00ULL) << 40)
| ((v & 0x00000000000000ffULL) << 56));
}
#endif // !defined(HAVE_BYTESWAP_H)
#endif // !HAVE_DECL_BSWAP64
// gcc 4.3 and later provides __builtin_bswap32 and __builtin_bswap64.