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

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

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@ -1,3 +1,15 @@
2020-06-26 Nick Alcock <nick.alcock@oracle.com>
PR libctf/25120
* 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.
2020-06-26 Nick Alcock <nick.alcock@oracle.com>
PR libctf/25120

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@ -13,6 +13,18 @@
don't. */
#undef HAVE_DECL_ASPRINTF
/* Define to 1 if you have the declaration of `bswap_16', and to 0 if you
don't. */
#undef HAVE_DECL_BSWAP_16
/* Define to 1 if you have the declaration of `bswap_32', and to 0 if you
don't. */
#undef HAVE_DECL_BSWAP_32
/* Define to 1 if you have the declaration of `bswap_64', and to 0 if you
don't. */
#undef HAVE_DECL_BSWAP_64
/* Define to 1 if you have the <dlfcn.h> header file. */
#undef HAVE_DLFCN_H

34
libctf/configure vendored
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@ -13028,6 +13028,40 @@ cat >>confdefs.h <<_ACEOF
#define HAVE_DECL_ASPRINTF $ac_have_decl
_ACEOF
ac_fn_c_check_decl "$LINENO" "bswap_16" "ac_cv_have_decl_bswap_16" "#include <byteswap.h>
"
if test "x$ac_cv_have_decl_bswap_16" = xyes; then :
ac_have_decl=1
else
ac_have_decl=0
fi
cat >>confdefs.h <<_ACEOF
#define HAVE_DECL_BSWAP_16 $ac_have_decl
_ACEOF
ac_fn_c_check_decl "$LINENO" "bswap_32" "ac_cv_have_decl_bswap_32" "#include <byteswap.h>
"
if test "x$ac_cv_have_decl_bswap_32" = xyes; then :
ac_have_decl=1
else
ac_have_decl=0
fi
cat >>confdefs.h <<_ACEOF
#define HAVE_DECL_BSWAP_32 $ac_have_decl
_ACEOF
ac_fn_c_check_decl "$LINENO" "bswap_64" "ac_cv_have_decl_bswap_64" "#include <byteswap.h>
"
if test "x$ac_cv_have_decl_bswap_64" = xyes; then :
ac_have_decl=1
else
ac_have_decl=0
fi
cat >>confdefs.h <<_ACEOF
#define HAVE_DECL_BSWAP_64 $ac_have_decl
_ACEOF

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@ -100,6 +100,8 @@ AC_CHECK_HEADERS(byteswap.h endian.h)
AC_CHECK_FUNCS(pread)
AC_CHECK_DECLS([asprintf])
dnl Check for bswap_{16,32,64}
AC_CHECK_DECLS([bswap_16, bswap_32, bswap_64], [], [], [[#include <byteswap.h>]])
dnl Check for qsort_r. (Taken from gnulib.)
AC_CHECK_FUNCS_ONCE([qsort_r])

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@ -25,15 +25,19 @@
#ifdef HAVE_BYTESWAP_H
#include <byteswap.h>
#else
#endif /* defined(HAVE_BYTESWAP_H) */
/* Provide our own versions of the byteswap functions. */
#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 */
#if !HAVE_DECL_BSWAP_32
static inline uint32_t
bswap_32 (uint32_t v)
{
@ -42,13 +46,9 @@ bswap_32 (uint32_t v)
| ((v & 0x0000ff00) << 8)
| ((v & 0x000000ff) << 24));
}
#endif /* !HAVE_DECL_BSWAP32 */
static inline uint64_t
bswap_identity_64 (uint64_t v)
{
return v;
}
#if !HAVE_DECL_BSWAP_64
static inline uint64_t
bswap_64 (uint64_t v)
{
@ -61,6 +61,6 @@ bswap_64 (uint64_t v)
| ((v & 0x000000000000ff00ULL) << 40)
| ((v & 0x00000000000000ffULL) << 56));
}
#endif /* !defined(HAVE_BYTESWAP_H) */
#endif /* !HAVE_DECL_BSWAP64 */
#endif /* !defined(_CTF_SWAP_H) */