2018-04-30 Raymond Nicholson <rain1@airmail.cc>
* manual/startup.texi (Aborting a Program): Remove inappropriate joke.
This complies with the decision of the project leader and primary and
ultimate maintainer, who partially delegated maintainership to myself
and others under certain constraints.
This is also in line with the community-agreed procedures.
It is obvious that we didn't have consensus on a decision to install
that patch, since both sides are still arguing over it.
As for the decision to reverse the deletion, if we even need one to
counter a move that did not have consensus, although nobody else offered
to install the reversal and restore the status prior to the fait
accompli, and some explicitly refused to do so themselves, nobody
objected when I offered to do so. Therefore, by the same reasoning that
led to the mistaken installation of the patch, and after a much longer
wait for objections, I understand there is consensus on my reverting it.
Since tile support has been removed from the Linux kernel for 4.17,
this patch removes the (unmaintained) port to tilegx from glibc (the
tilepro support having been previously removed). This reflects the
general principle that a glibc port needs upstream support for the
architecture in all the components it build-depends on (so binutils,
GCC and the Linux kernel, for the normal case of a port supporting the
Linux kernel but no other OS), in order to be maintainable.
Apart from removal of sysdeps/tile and sysdeps/unix/sysv/linux/tile,
there are updates to various comments referencing tile for which
removal of those references seemed appropriate. The configuration is
removed from README and from build-many-glibcs.py. contrib.texi keeps
mention of removed contributions, but I updated Chris Metcalf's entry
to reflect that he also contributed the non-removed support for the
generic Linux kernel syscall interface.
__ASSUME_FADVISE64_64_NO_ALIGN support is removed, as it was only used
by tile.
* sysdeps/tile: Remove.
* sysdeps/unix/sysv/linux/tile: Likewise.
* README (tilegx-*-linux-gnu): Remove from list of supported
configurations.
* manual/contrib.texi (Contributors): Mention Chris Metcalf's
contribution of support for generic Linux kernel syscall
interface.
* scripts/build-many-glibcs.py (Context.add_all_configs): Remove
tilegx configurations.
(Config.install_linux_headers): Do not handle tile.
* sysdeps/unix/sysv/linux/aarch64/ldsodefs.h: Do not mention Tile
in comment.
* sysdeps/unix/sysv/linux/nios2/Makefile: Likewise.
* sysdeps/unix/sysv/linux/posix_fadvise.c: Likewise.
[__ASSUME_FADVISE64_64_NO_ALIGN] (__ALIGNMENT_ARG): Remove
conditional undefine and redefine.
* sysdeps/unix/sysv/linux/posix_fadvise64.c: Do not mention Tile
in comment.
[__ASSUME_FADVISE64_64_NO_ALIGN] (__ALIGNMENT_ARG): Remove
conditional undefine and redefine.
The example did not work because the null byte was not converted, and
mbrtowc was called with a zero-length input string. This results in a
(size_t) -2 return value, so the function always returns NULL.
The size computation for the heap allocation of the result was
incorrect because it did not deal with integer overflow.
Error checking was missing, and the allocated memory was not freed on
error paths. All error returns now set errno. (Note that there is an
assumption that free does not clobber errno.)
The slightly unportable comparision against (size_t) -2 to catch both
(size_t) -1 and (size_t) -2 return values is gone as well.
A null wide character needs to be stored in the result explicitly, to
terminate it.
The description in the manual is updated to deal with these finer
points. The (size_t) -2 behavior (consuming the input bytes) matches
what is specified in ISO C11.
* manual/errno.texi (EOWNERDEAD, ENOTRECOVERABLE): Remove errno
values from Linux-specific section now that it is in the GNU section.
* sysdeps/gnu/errlist.c: Regenerate.
* hurd/Makefile (routines): Add hurdlock.
* hurd/Versions (GLIBC_PRIVATE): Added new entry to export the above
interface.
(HURD_CTHREADS_0.3): Remove __libc_getspecific.
* hurd/hurdpid.c: Include <lowlevellock.h>
(_S_msg_proc_newids): Use lll_wait to synchronize.
* hurd/hurdsig.c: (reauth_proc): Use __mutex_lock and __mutex_unlock.
* hurd/setauth.c: Include <hurdlock.h>, use integer for synchronization.
* mach/Makefile (lock-headers): Remove machine-lock.h.
* mach/lock-intern.h: Include <lowlevellock.h> instead of
<machine-lock.h>.
(__spin_lock_t): New type.
(__SPIN_LOCK_INITIALIZER): New macro.
(__spin_lock, __spin_unlock, __spin_try_lock, __spin_lock_locked,
__mutex_init, __mutex_lock_solid, __mutex_unlock_solid, __mutex_lock,
__mutex_unlock, __mutex_trylock): Use lll to implement locks.
* mach/mutex-init.c: Include <lowlevellock.h> instead of <cthreads.h>.
(__mutex_init): Initialize with lll.
* manual/errno.texi (EOWNERDEAD, ENOTRECOVERABLE): New errno values.
* sysdeps/mach/Makefile: Add libmachuser as dependencies for libs
needing lll.
* sysdeps/mach/hurd/bits/errno.h: Regenerate.
* sysdeps/mach/hurd/cthreads.c (__libc_getspecific): Remove function.
* sysdeps/mach/hurd/bits/libc-lock.h: Remove file.
* sysdeps/mach/hurd/setpgid.c: Include <lowlevellock.h>.
(__setpgid): Use lll for synchronization.
* sysdeps/mach/hurd/setsid.c: Likewise with __setsid.
* sysdeps/mach/bits/libc-lock.h: Include <tls.h> and <lowlevellock.h>
instead of <cthreads.h>.
(_IO_lock_inexpensive): New macro
(__libc_lock_recursive_t, __rtld_lock_recursive_t): New structures.
(__libc_lock_self0): New declaration.
(__libc_lock_owner_self): New macro.
(__libc_key_t): Remove type.
(_LIBC_LOCK_INITIALIZER): New macro.
(__libc_lock_define_initialized, __libc_lock_init, __libc_lock_fini,
__libc_lock_fini_recursive, __rtld_lock_fini_recursive,
__libc_lock_lock, __libc_lock_trylock, __libc_lock_unlock,
__libc_lock_define_initialized_recursive,
__rtld_lock_define_initialized_recursive,
__libc_lock_init_recursive, __libc_lock_trylock_recursive,
__libc_lock_lock_recursive, __libc_lock_unlock_recursive,
__rtld_lock_initialize, __rtld_lock_trylock_recursive,
__rtld_lock_lock_recursive, __rtld_lock_unlock_recursive
__libc_once_define, __libc_mutex_unlock): Reimplement with lll.
(__libc_lock_define_recursive, __rtld_lock_define_recursive,
_LIBC_LOCK_RECURSIVE_INITIALIZER, _RTLD_LOCK_RECURSIVE_INITIALIZER):
New macros.
Include <libc-lockP.h> to reimplement libc_key* with pthread_key*.
* hurd/hurdlock.c: New file.
* hurd/hurdlock.h: New file.
* mach/lowlevellock.h: New file
The description of the interplay between feature test macros and
compiler options in the description of _DEFAULT_SOURCE is a little
confusing, and dated, so clarify the situation, and don't assume a
specific value for _DEFAULT_SOURCE.
Also, _DEFAULT_SOURCE is supposed to be defined if none of the C/POSIX
feature test macros are defined, but the condition was lacking a test
for _ISOC11_SOURCE, so that is also addressed.
[BZ #22862]
* include/features.h: Add _ISOC11_SOURCE to test for whether
to define _DEFAULT_SOURCE.
* manual/creature.texi (_DEFAULT_SOURCE): Improve
documentation.
The current description refers to ISO C99 not being widely adopted,
which it is believed to be now.
* manual/creature.texi (_ISOC99_SOURCE): Update the dated
description.
Several feature test macros are documented in features.h but absent in
the manual, and some documented macros accept undocumented values.
This commit updates the manual to mention all the accepted macros,
along with any values that hold special meaning.
* manual/creature.texi (_POSIX_C_SOURCE): Document special
values of 199606L, 200112L, and 200809L.
(_XOPEN_SOURCE): Document special values of 600 and 700.
(_ISOC11_SOURCE): Document macro.
(_ATFILE_SOURCE): Likewise.
(_FORTIFY_SOURCE): Likewise.
This is a minor rewording to clarify the behaviour of
get_current_dir_name. Additionally, the @vindex is moved above the
@deftypefun so that following links give a better result with regard
to context.
[BZ #6889]
* manual/filesys.texi (get_current_dir_name): Clarify
behaviour.
The opening parenthesis for function arguments in an @deftypefun need
to be separated from the function name. This isn't just a matter of
the GNU coding style---it causes the "(void" (in this case) to be
rendered as a part of the function name, causing a visual defect, and
also results in a warning to the following effect during `make pdf':
Warning: unbalanced parentheses in @def...)
* manual/platform.texi (__riscv_flush_icache): Fix @deftypefun
syntax.
There are some bug reports from people setting CFLAGS not including a
-O option and then being confused when the build fails. This patch
addresses this by documenting the proper use of CC and CFLAGS in more
detail - saying what options should go where and specifying the
requirement to compile with optimization.
The previous text incorrectly used @var markup with CC and CFLAGS.
The correct markup for environment variables is @env, but it's also
the case that passing such variables explicitly on the configure
command line is preferred to passing them in the environment, so this
patch changes the documentation to describe passing them on the
command line (and uses @code).
In many cases putting options in the wrong place may in fact work, but
I believe what I've specified is the correct rule for which options to
put where.
[BZ #20980]
[BZ #21234]
* manual/install.texi (Configuring and compiling): Describe
passing CC and CFLAGS on configure command line, not as
environment variables. Use @code markup on those variables.
Specify what options go in CC and what go in CFLAGS. Note the
requirement to compile with optimization.
* INSTALL: Regenerated.
Remove the slow paths from pow. Like several other double precision math
functions, pow is exactly rounded. This is not required from math functions
and causes major overheads as it requires multiple fallbacks using higher
precision arithmetic if a result is close to 0.5ULP. Ridiculous slowdowns
of up to 100000x have been reported when the highest precision path triggers.
All GLIBC math tests pass on AArch64 and x64 (with ULP of pow set to 1).
The worst case error is ~0.506ULP. A simple test over a few hundred million
values shows pow is 10% faster on average. This fixes BZ #13932.
[BZ #13932]
* sysdeps/ieee754/dbl-64/uexp.h (err_1): Remove.
* benchtests/pow-inputs: Update comment for slow path cases.
* manual/probes.texi (slowpow_p10): Delete removed probe.
(slowpow_p10): Likewise.
* math/Makefile: Remove halfulp.c and slowpow.c.
* sysdeps/aarch64/libm-test-ulps: Set ULP of pow to 1.
* sysdeps/generic/math_private.h (__exp1): Remove error argument.
(__halfulp): Remove.
(__slowpow): Remove.
* sysdeps/i386/fpu/halfulp.c: Delete file.
* sysdeps/i386/fpu/slowpow.c: Likewise.
* sysdeps/ia64/fpu/halfulp.c: Likewise.
* sysdeps/ia64/fpu/slowpow.c: Likewise.
* sysdeps/ieee754/dbl-64/e_exp.c (__exp1): Remove error argument,
improve comments and add error analysis.
* sysdeps/ieee754/dbl-64/e_pow.c (__ieee754_pow): Add error analysis.
(power1): Remove function:
(log1): Remove error argument, add error analysis.
(my_log2): Remove function.
* sysdeps/ieee754/dbl-64/halfulp.c: Delete file.
* sysdeps/ieee754/dbl-64/slowpow.c: Likewise.
* sysdeps/m68k/m680x0/fpu/halfulp.c: Likewise.
* sysdeps/m68k/m680x0/fpu/slowpow.c: Likewise.
* sysdeps/powerpc/power4/fpu/Makefile: Remove CPPFLAGS-slowpow.c.
* sysdeps/x86_64/fpu/libm-test-ulps: Set ULP of pow to 1.
* sysdeps/x86_64/fpu/multiarch/Makefile: Remove slowpow-fma.c,
slowpow-fma4.c, halfulp-fma.c, halfulp-fma4.c.
* sysdeps/x86_64/fpu/multiarch/e_pow-fma.c (__slowpow): Remove define.
* sysdeps/x86_64/fpu/multiarch/e_pow-fma4.c (__slowpow): Likewise.
* sysdeps/x86_64/fpu/multiarch/halfulp-fma.c: Delete file.
* sysdeps/x86_64/fpu/multiarch/halfulp-fma4.c: Likewise.
* sysdeps/x86_64/fpu/multiarch/slowpow-fma.c: Likewise.
* sysdeps/x86_64/fpu/multiarch/slowpow-fma4.c: Likewise.
This patch adds the narrowing add functions from TS 18661-1 to glibc's
libm: fadd, faddl, daddl, f32addf64, f32addf32x, f32xaddf64 for all
configurations; f32addf64x, f32addf128, f64addf64x, f64addf128,
f32xaddf64x, f32xaddf128, f64xaddf128 for configurations with
_Float64x and _Float128; __nldbl_daddl for ldbl-opt. As discussed for
the build infrastructure patch, tgmath.h support is deliberately
deferred, and FP_FAST_* macros are not applicable without optimized
function implementations.
Function implementations are added for all relevant pairs of formats
(including certain cases of a format and itself where more than one
type has that format). The main implementations use round-to-odd, or
a trivial computation in the case where both formats are the same or
where the wider format is IBM long double (in which case we don't
attempt to be correctly rounding). The sysdeps/ieee754/soft-fp
implementations use soft-fp, and are used automatically for
configurations without exceptions and rounding modes by virtue of
existing Implies files. As previously discussed, optimized versions
for particular architectures are possible, but not included.
i386 gets a special version of f32xaddf64 to avoid problems with
double rounding (similar to the existing fdim version), since this
function must round just once without an intermediate rounding to long
double. (No such special version is needed for any other function,
because the nontrivial functions use round-to-odd, which does the
intermediate computation with the rounding mode set to round-to-zero,
and double rounding is OK except in round-to-nearest mode, so is OK
for that intermediate round-to-zero computation.) mul and div will
need slightly different special versions for i386 (using round-to-odd
on long double instead of precision control) because of the
possibility of inexact intermediate results in the subnormal range for
double.
To reduce duplication among the different function implementations,
math-narrow.h gets macros CHECK_NARROW_ADD, NARROW_ADD_ROUND_TO_ODD
and NARROW_ADD_TRIVIAL.
In the trivial cases and for any architecture-specific optimized
implementations, the overhead of the errno setting might be
significant, but I think that's best handled through compiler built-in
functions rather than providing separate no-errno versions in glibc
(and likewise there are no __*_finite entry points for these function
provided, __*_finite effectively being no-errno versions at present in
most cases).
Tested for x86_64 and x86, with both GCC 6 and GCC 7. Tested for
mips64 (all three ABIs, both hard and soft float) and powerpc with GCC
7. Tested with build-many-glibcs.py with both GCC 6 and GCC 7.
* math/Makefile (libm-narrow-fns): Add add.
(libm-test-funcs-narrow): Likewise.
* math/Versions (GLIBC_2.28): Add narrowing add functions.
* math/bits/mathcalls-narrow.h (add): Use __MATHCALL_NARROW .
* math/gen-auto-libm-tests.c (test_functions): Add add.
* math/math-narrow.h (CHECK_NARROW_ADD): New macro.
(NARROW_ADD_ROUND_TO_ODD): Likewise.
(NARROW_ADD_TRIVIAL): Likewise.
* sysdeps/ieee754/float128/float128_private.h (__faddl): New
macro.
(__daddl): Likewise.
* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add fadd and
dadd.
(CFLAGS-nldbl-dadd.c): New variable.
(CFLAGS-nldbl-fadd.c): Likewise.
* sysdeps/ieee754/ldbl-opt/Versions (GLIBC_2.28): Add
__nldbl_daddl.
* sysdeps/ieee754/ldbl-opt/nldbl-compat.h (__nldbl_daddl): New
prototype.
* manual/arith.texi (Misc FP Arithmetic): Document fadd, faddl,
daddl, fMaddfN, fMaddfNx, fMxaddfN and fMxaddfNx.
* math/auto-libm-test-in: Add tests of add.
* math/auto-libm-test-out-narrow-add: New generated file.
* math/libm-test-narrow-add.inc: New file.
* sysdeps/i386/fpu/s_f32xaddf64.c: Likewise.
* sysdeps/ieee754/dbl-64/s_f32xaddf64.c: Likewise.
* sysdeps/ieee754/dbl-64/s_fadd.c: Likewise.
* sysdeps/ieee754/float128/s_f32addf128.c: Likewise.
* sysdeps/ieee754/float128/s_f64addf128.c: Likewise.
* sysdeps/ieee754/float128/s_f64xaddf128.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_daddl.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_f64xaddf128.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_faddl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_daddl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_faddl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_daddl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_faddl.c: Likewise.
* sysdeps/ieee754/ldbl-opt/nldbl-dadd.c: Likewise.
* sysdeps/ieee754/ldbl-opt/nldbl-fadd.c: Likewise.
* sysdeps/ieee754/soft-fp/s_daddl.c: Likewise.
* sysdeps/ieee754/soft-fp/s_fadd.c: Likewise.
* sysdeps/ieee754/soft-fp/s_faddl.c: Likewise.
* sysdeps/powerpc/fpu/libm-test-ulps: Update.
* sysdeps/mach/hurd/i386/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/nios2/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/riscv/rv64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
A number of cross-references to the GCC info manual cause Texinfo
warnings; e.g.:
./creature.texi:11: warning: @xref node name should not contain `.'
This is due to "gcc.info" being used in the INFO-FILE-NAME (fourth)
argument. Changing it to "gcc" removes these warnings. (Manually
confirmed equivalent behaviour for make info, html, and pdf.)
* manual/creature.texi: Convert references to gcc.info to gcc.
* manual/stdio.texi: Likewise.
* manual/string.texi: Likewise.
Remove the slow paths from log. Like several other double precision math
functions, log is exactly rounded. This is not required from math functions
and causes major overheads as it requires multiple fallbacks using higher
precision arithmetic if a result is close to 0.5ULP. Ridiculous slowdowns
of up to 100000x have been reported when the highest precision path triggers.
Interestingly removing the slow paths makes hardly any difference in practice:
the worst case error is still ~0.502ULP, and exp(log(x)) shows identical results
before/after on many millions of random cases. All GLIBC math tests pass on
AArch64 and x64 with no change in ULP error. A simple test over a few hundred
million values shows log is now 18% faster on average.
* manual/probes.texi (slowlog): Delete documentation of removed probe.
(slowlog_inexact): Likewise
* sysdeps/ieee754/dbl-64/e_log.c (__ieee754_log): Remove slow paths.
* sysdeps/ieee754/dbl-64/ulog.h: Remove unused declarations.
This function is used by GCC to enforce ordering between data writes and
instruction fetches, and while we'd prefer that users rely on the GCC
intrinsic when possible this is user visible in case that's not
possible.
2018-01-29 Palmer Dabbelt <palmer@sifive.com>
* manual/platform.texi: Add RISC-V documenation for
__riscv_flush_icache.
During the upstreaming process it was suggested that I add a handful of
small documentation entries about the RISC-V port, which I've collected
here.
2018-01-29 Palmer Dabbelt <palmer@sifive.com>
* manual/math.texi: RISC-V supports _Float128 and _Float64x.
"%OB" is considered a conversion specifier ("B" is the format
specifier), and the list of format specifiers for months in the
description of the optional "O" modifier was incomplete. A
cross-reference from the ALTMON_* constants to the strftime section
is also provided. Lastly, some grammatical fixes (commas) are made
and paragraphs refactored (rewrapped).
* manual/locale.texi (ALTMON_1, ALTMON_2, ALTMON_3, ALTMON_4,
ALTMON_5, ALTMON_6, ALTMON_7, ALTMON_8, ALTMON_9, ALTMON_10,
ALTMON_11, ALTMON_12): Improve documentation.
* manual/time.texi (strftime): Likewise.
[BZ #10871]
* manual/locale.texi: Document ALTMON_1..12 constants for
nl_langinfo. Specify when to use ALTMON instead of MON.
* manual/time.texi (strftime, strptime): Document GNU extension
permitting O modifier with %B and %b. Specify when to use
%OB instead of %B.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This patch updates various files from their upstream sources. This
brings in copyright date updates for some of those files.
Tested for x86_64.
* manual/texinfo.tex: Update to version 2017-12-26.21 with
trailing whitespace removed.
* scripts/config.guess: Update to version 2018-01-01.
* scripts/config.sub: Update to version 2018-01-01.
* scripts/move-if-change: Update from gnulib.
The current glibc manual is ambiguous about the errno value on success
and suggests that it is left unchanged. Some functions might and
sometimes do change the errno value, however they never set it to 0.
This patch from Zack Weinberg clarifies this section of the manual.
Changelog:
[BZ #22615]
* manual/errno.texi (Checking for Errors): Explicitly say that errno
might be set on success.
That way it matches the standard and the behaviour of the finite
function.
Changelog:
[BZ #22596]
* manual/arith.texi (finite): Fix the description of the return
value.
This patch updates various miscellaneous files from their upstream
sources.
Tested for x86_64, including "make pdf".
* manual/texinfo.tex: Update to version 2017-12-18.20 with
trailing whitespace removed.
* scripts/config.guess: Update to version 2017-12-17.
* scripts/config.sub: Update to version 2017-11-23.
* scripts/install-sh: Update to version 2017-09-23.17.
* scripts/move-if-change: Update to version 2017-09-13 06:45.
To build static PIE, all .o files are compiled with -fPIE. Since
--enable-static-pie is designed to provide additional security hardening
benefits, it also implies that glibc programs and tests are created as
dynamic position independent executables (PIE) by default for better
security hardening.
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
* manual/install.texi: Document that --enable-static-pie
implies PIE.
* INSTALL: Regenerated.
These changes will be active for all platforms that don't provide
their own exp() routines. They will also be active for ieee754
versions of ccos, ccosh, cosh, csin, csinh, sinh, exp10, gamma, and
erf.
Typical performance gains is typically around 5x when measured on
Sparc s7 for common values between exp(1) and exp(40).
Using the glibc perf tests on sparc,
sparc (nsec) x86 (nsec)
old new old new
max 17629 395 5173 144
min 399 54 15 13
mean 5317 200 1349 23
The extreme max times for the old (ieee754) exp are due to the
multiprecision computation in the old algorithm when the true value is
very near 0.5 ulp away from an value representable in double
precision. The new algorithm does not take special measures for those
cases. The current glibc exp perf tests overrepresent those values.
Informal testing suggests approximately one in 200 cases might
invoke the high cost computation. The performance advantage of the new
algorithm for other values is still large but not as large as indicated
by the chart above.
Glibc correctness tests for exp() and expf() were run. Within the
test suite 3 input values were found to cause 1 bit differences (ulp)
when "FE_TONEAREST" rounding mode is set. No differences in exp() were
seen for the tested values for the other rounding modes.
Typical example:
exp(-0x1.760cd2p+0) (-1.46113312244415283203125)
new code: 2.31973271630014299393707e-01 0x1.db14cd799387ap-3
old code: 2.31973271630014271638132e-01 0x1.db14cd7993879p-3
exp = 2.31973271630014285508337 (high precision)
Old delta: off by 0.49 ulp
New delta: off by 0.51 ulp
In addition, because ieee754_exp() is used by other routines, cexp()
showed test results with very small imaginary input values where the
imaginary portion of the result was off by 3 ulp when in upward
rounding mode, but not in the other rounding modes. For x86, tgamma
showed a few values where the ulp increased to 6 (max ulp for tgamma
is 5). Sparc tgamma did not show these failures. I presume the tgamma
differences are due to compiler optimization differences within the
gamma function.The gamma function is known to be difficult to compute
accurately.
* sysdeps/ieee754/dbl-64/e_exp.c: Include <math-svid-compat.h> and
<errno.h>. Include "eexp.tbl".
(half): New constant.
(one): Likewise.
(__ieee754_exp): Rewrite.
(__slowexp): Remove prototype.
* sysdeps/ieee754/dbl-64/eexp.tbl: New file.
* sysdeps/ieee754/dbl-64/slowexp.c: Remove file.
* sysdeps/i386/fpu/slowexp.c: Likewise.
* sysdeps/ia64/fpu/slowexp.c: Likewise.
* sysdeps/m68k/m680x0/fpu/slowexp.c: Likewise.
* sysdeps/x86_64/fpu/multiarch/slowexp-avx.c: Likewise.
* sysdeps/x86_64/fpu/multiarch/slowexp-fma.c: Likewise.
* sysdeps/x86_64/fpu/multiarch/slowexp-fma4.c: Likewise.
* sysdeps/generic/math_private.h (__slowexp): Remove prototype.
* sysdeps/ieee754/dbl-64/e_pow.c: Remove mention of slowexp.c in
comment.
* sysdeps/powerpc/power4/fpu/Makefile [$(subdir) = math]
(CPPFLAGS-slowexp.c): Remove variable.
* sysdeps/x86_64/fpu/multiarch/Makefile (libm-sysdep_routines):
Remove slowexp-fma, slowexp-fma4 and slowexp-avx.
(CFLAGS-slowexp-fma.c): Remove variable.
(CFLAGS-slowexp-fma4.c): Likewise.
(CFLAGS-slowexp-avx.c): Likewise.
* sysdeps/x86_64/fpu/multiarch/e_exp-avx.c (__slowexp): Do not
define as macro.
* sysdeps/x86_64/fpu/multiarch/e_exp-fma.c (__slowexp): Likewise.
* sysdeps/x86_64/fpu/multiarch/e_exp-fma4.c (__slowexp): Likewise.
* math/Makefile (type-double-routines): Remove slowexp.
* manual/probes.texi (slowexp_p6): Remove.
(slowexp_p32): Likewise.
Static PIE extends address space layout randomization to static
executables. It provides additional security hardening benefits at
the cost of some memory and performance.
Dynamic linker, ld.so, is a standalone program which can be loaded at
any address. This patch adds a configure option, --enable-static-pie,
to embed the part of ld.so in static executable to create static position
independent executable (static PIE). A static PIE is similar to static
executable, but can be loaded at any address without help from a dynamic
linker. When --enable-static-pie is used to configure glibc, libc.a is
built as PIE and all static executables, including tests, are built as
static PIE. The resulting libc.a can be used together with GCC 8 or
above to build static PIE with the compiler option, -static-pie. But
GCC 8 isn't required to build glibc with --enable-static-pie. Only GCC
with PIE support is needed. When an older GCC is used to build glibc
with --enable-static-pie, proper input files are passed to linker to
create static executables as static PIE, together with "-z text" to
prevent dynamic relocations in read-only segments, which are not allowed
in static PIE.
The following changes are made for static PIE:
1. Add a new function, _dl_relocate_static_pie, to:
a. Get the run-time load address.
b. Read the dynamic section.
c. Perform dynamic relocations.
Dynamic linker also performs these steps. But static PIE doesn't load
any shared objects.
2. Call _dl_relocate_static_pie at entrance of LIBC_START_MAIN in
libc.a. crt1.o, which is used to create dynamic and non-PIE static
executables, is updated to include a dummy _dl_relocate_static_pie.
rcrt1.o is added to create static PIE, which will link in the real
_dl_relocate_static_pie. grcrt1.o is also added to create static PIE
with -pg. GCC 8 has been updated to support rcrt1.o and grcrt1.o for
static PIE.
Static PIE can work on all architectures which support PIE, provided:
1. Target must support accessing of local functions without dynamic
relocations, which is needed in start.S to call __libc_start_main with
function addresses of __libc_csu_init, __libc_csu_fini and main. All
functions in static PIE are local functions. If PIE start.S can't reach
main () defined in a shared object, the code sequence:
pass address of local_main to __libc_start_main
...
local_main:
tail call to main via PLT
can be used.
2. start.S is updated to check PIC instead SHARED for PIC code path and
avoid dynamic relocation, when PIC is defined and SHARED isn't defined,
to support static PIE.
3. All assembly codes are updated check PIC instead SHARED for PIC code
path to avoid dynamic relocations in read-only sections.
4. All assembly codes are updated check SHARED instead PIC for static
symbol name.
5. elf_machine_load_address in dl-machine.h are updated to support static
PIE.
6. __brk works without TLS nor dynamic relocations in read-only section
so that it can be used by __libc_setup_tls to initializes TLS in static
PIE.
NB: When glibc is built with GCC defaulted to PIE, libc.a is compiled
with -fPIE, regardless if --enable-static-pie is used to configure glibc.
When glibc is configured with --enable-static-pie, libc.a is compiled
with -fPIE, regardless whether GCC defaults to PIE or not. The same
libc.a can be used to build both static executable and static PIE.
There is no need for separate PIE copy of libc.a.
On x86-64, the normal static sln:
text data bss dec hex filename
625425 8284 5456 639165 9c0bd elf/sln
the static PIE sln:
text data bss dec hex filename
657626 20636 5392 683654 a6e86 elf/sln
The code size is increased by 5% and the binary size is increased by 7%.
Linker requirements to build glibc with --enable-static-pie:
1. Linker supports --no-dynamic-linker to remove PT_INTERP segment from
static PIE.
2. Linker can create working static PIE. The x86-64 linker needs the
fix for
https://sourceware.org/bugzilla/show_bug.cgi?id=21782
The i386 linker needs to be able to convert "movl main@GOT(%ebx), %eax"
to "leal main@GOTOFF(%ebx), %eax" if main is defined locally.
Binutils 2.29 or above are OK for i686 and x86-64. But linker status for
other targets need to be verified.
3. Linker should resolve undefined weak symbols to 0 in static PIE:
https://sourceware.org/bugzilla/show_bug.cgi?id=22269
4. Many ELF backend linkers incorrectly check bfd_link_pic for TLS
relocations, which should check bfd_link_executable instead:
https://sourceware.org/bugzilla/show_bug.cgi?id=22263
Tested on aarch64, i686 and x86-64.
Using GCC 7 and binutils master branch, build-many-glibcs.py with
--enable-static-pie with all patches for static PIE applied have the
following build successes:
PASS: glibcs-aarch64_be-linux-gnu build
PASS: glibcs-aarch64-linux-gnu build
PASS: glibcs-armeb-linux-gnueabi-be8 build
PASS: glibcs-armeb-linux-gnueabi build
PASS: glibcs-armeb-linux-gnueabihf-be8 build
PASS: glibcs-armeb-linux-gnueabihf build
PASS: glibcs-arm-linux-gnueabi build
PASS: glibcs-arm-linux-gnueabihf build
PASS: glibcs-arm-linux-gnueabihf-v7a build
PASS: glibcs-arm-linux-gnueabihf-v7a-disable-multi-arch build
PASS: glibcs-m68k-linux-gnu build
PASS: glibcs-microblazeel-linux-gnu build
PASS: glibcs-microblaze-linux-gnu build
PASS: glibcs-mips64el-linux-gnu-n32 build
PASS: glibcs-mips64el-linux-gnu-n32-nan2008 build
PASS: glibcs-mips64el-linux-gnu-n32-nan2008-soft build
PASS: glibcs-mips64el-linux-gnu-n32-soft build
PASS: glibcs-mips64el-linux-gnu-n64 build
PASS: glibcs-mips64el-linux-gnu-n64-nan2008 build
PASS: glibcs-mips64el-linux-gnu-n64-nan2008-soft build
PASS: glibcs-mips64el-linux-gnu-n64-soft build
PASS: glibcs-mips64-linux-gnu-n32 build
PASS: glibcs-mips64-linux-gnu-n32-nan2008 build
PASS: glibcs-mips64-linux-gnu-n32-nan2008-soft build
PASS: glibcs-mips64-linux-gnu-n32-soft build
PASS: glibcs-mips64-linux-gnu-n64 build
PASS: glibcs-mips64-linux-gnu-n64-nan2008 build
PASS: glibcs-mips64-linux-gnu-n64-nan2008-soft build
PASS: glibcs-mips64-linux-gnu-n64-soft build
PASS: glibcs-mipsel-linux-gnu build
PASS: glibcs-mipsel-linux-gnu-nan2008 build
PASS: glibcs-mipsel-linux-gnu-nan2008-soft build
PASS: glibcs-mipsel-linux-gnu-soft build
PASS: glibcs-mips-linux-gnu build
PASS: glibcs-mips-linux-gnu-nan2008 build
PASS: glibcs-mips-linux-gnu-nan2008-soft build
PASS: glibcs-mips-linux-gnu-soft build
PASS: glibcs-nios2-linux-gnu build
PASS: glibcs-powerpc64le-linux-gnu build
PASS: glibcs-powerpc64-linux-gnu build
PASS: glibcs-tilegxbe-linux-gnu-32 build
PASS: glibcs-tilegxbe-linux-gnu build
PASS: glibcs-tilegx-linux-gnu-32 build
PASS: glibcs-tilegx-linux-gnu build
PASS: glibcs-tilepro-linux-gnu build
and the following build failures:
FAIL: glibcs-alpha-linux-gnu build
elf/sln is failed to link due to:
assertion fail bfd/elf64-alpha.c:4125
This is caused by linker bug and/or non-PIC code in PIE libc.a.
FAIL: glibcs-hppa-linux-gnu build
elf/sln is failed to link due to:
collect2: fatal error: ld terminated with signal 11 [Segmentation fault]
https://sourceware.org/bugzilla/show_bug.cgi?id=22537
FAIL: glibcs-ia64-linux-gnu build
elf/sln is failed to link due to:
collect2: fatal error: ld terminated with signal 11 [Segmentation fault]
FAIL: glibcs-powerpc-linux-gnu build
FAIL: glibcs-powerpc-linux-gnu-soft build
FAIL: glibcs-powerpc-linux-gnuspe build
FAIL: glibcs-powerpc-linux-gnuspe-e500v1 build
elf/sln is failed to link due to:
ld: read-only segment has dynamic relocations.
This is caused by linker bug and/or non-PIC code in PIE libc.a. See:
https://sourceware.org/bugzilla/show_bug.cgi?id=22264
FAIL: glibcs-powerpc-linux-gnu-power4 build
elf/sln is failed to link due to:
findlocale.c:96:(.text+0x22c): @local call to ifunc memchr
This is caused by linker bug and/or non-PIC code in PIE libc.a.
FAIL: glibcs-s390-linux-gnu build
elf/sln is failed to link due to:
collect2: fatal error: ld terminated with signal 11 [Segmentation fault], core dumped
assertion fail bfd/elflink.c:14299
This is caused by linker bug and/or non-PIC code in PIE libc.a.
FAIL: glibcs-sh3eb-linux-gnu build
FAIL: glibcs-sh3-linux-gnu build
FAIL: glibcs-sh4eb-linux-gnu build
FAIL: glibcs-sh4eb-linux-gnu-soft build
FAIL: glibcs-sh4-linux-gnu build
FAIL: glibcs-sh4-linux-gnu-soft build
elf/sln is failed to link due to:
ld: read-only segment has dynamic relocations.
This is caused by linker bug and/or non-PIC code in PIE libc.a. See:
https://sourceware.org/bugzilla/show_bug.cgi?id=22263
Also TLS code sequence in SH assembly syscalls in glibc doesn't match TLS
code sequence expected by ld:
https://sourceware.org/bugzilla/show_bug.cgi?id=22270
FAIL: glibcs-sparc64-linux-gnu build
FAIL: glibcs-sparcv9-linux-gnu build
FAIL: glibcs-tilegxbe-linux-gnu build
FAIL: glibcs-tilegxbe-linux-gnu-32 build
FAIL: glibcs-tilegx-linux-gnu build
FAIL: glibcs-tilegx-linux-gnu-32 build
FAIL: glibcs-tilepro-linux-gnu build
elf/sln is failed to link due to:
ld: read-only segment has dynamic relocations.
This is caused by linker bug and/or non-PIC code in PIE libc.a. See:
https://sourceware.org/bugzilla/show_bug.cgi?id=22263
[BZ #19574]
* INSTALL: Regenerated.
* Makeconfig (real-static-start-installed-name): New.
(pic-default): Updated for --enable-static-pie.
(pie-default): New for --enable-static-pie.
(default-pie-ldflag): Likewise.
(+link-static-before-libc): Replace $(DEFAULT-LDFLAGS-$(@F))
with $(if $($(@F)-no-pie),$(no-pie-ldflag),$(default-pie-ldflag)).
Replace $(static-start-installed-name) with
$(real-static-start-installed-name).
(+prectorT): Updated for --enable-static-pie.
(+postctorT): Likewise.
(CFLAGS-.o): Add $(pie-default).
(CFLAGS-.op): Likewise.
* NEWS: Mention --enable-static-pie.
* config.h.in (ENABLE_STATIC_PIE): New.
* configure.ac (--enable-static-pie): New configure option.
(have-no-dynamic-linker): New LIBC_CONFIG_VAR.
(have-static-pie): Likewise.
Enable static PIE if linker supports --no-dynamic-linker.
(ENABLE_STATIC_PIE): New AC_DEFINE.
(enable-static-pie): New LIBC_CONFIG_VAR.
* configure: Regenerated.
* csu/Makefile (omit-deps): Add r$(start-installed-name) and
gr$(start-installed-name) for --enable-static-pie.
(extra-objs): Likewise.
(install-lib): Likewise.
(extra-objs): Add static-reloc.o and static-reloc.os
($(objpfx)$(start-installed-name)): Also depend on
$(objpfx)static-reloc.o.
($(objpfx)r$(start-installed-name)): New.
($(objpfx)g$(start-installed-name)): Also depend on
$(objpfx)static-reloc.os.
($(objpfx)gr$(start-installed-name)): New.
* csu/libc-start.c (LIBC_START_MAIN): Call _dl_relocate_static_pie
in libc.a.
* csu/libc-tls.c (__libc_setup_tls): Add main_map->l_addr to
initimage.
* csu/static-reloc.c: New file.
* elf/Makefile (routines): Add dl-reloc-static-pie.
(elide-routines.os): Likewise.
(DEFAULT-LDFLAGS-tst-tls1-static-non-pie): Removed.
(tst-tls1-static-non-pie-no-pie): New.
* elf/dl-reloc-static-pie.c: New file.
* elf/dl-support.c (_dl_get_dl_main_map): New function.
* elf/dynamic-link.h (ELF_DURING_STARTUP): Also check
STATIC_PIE_BOOTSTRAP.
* elf/get-dynamic-info.h (elf_get_dynamic_info): Likewise.
* gmon/Makefile (tests): Add tst-gmon-static-pie.
(tests-static): Likewise.
(DEFAULT-LDFLAGS-tst-gmon-static): Removed.
(tst-gmon-static-no-pie): New.
(CFLAGS-tst-gmon-static-pie.c): Likewise.
(CRT-tst-gmon-static-pie): Likewise.
(tst-gmon-static-pie-ENV): Likewise.
(tests-special): Likewise.
($(objpfx)tst-gmon-static-pie.out): Likewise.
(clean-tst-gmon-static-pie-data): Likewise.
($(objpfx)tst-gmon-static-pie-gprof.out): Likewise.
* gmon/tst-gmon-static-pie.c: New file.
* manual/install.texi: Document --enable-static-pie.
* sysdeps/generic/ldsodefs.h (_dl_relocate_static_pie): New.
(_dl_get_dl_main_map): Likewise.
* sysdeps/i386/configure.ac: Check if linker supports static PIE.
* sysdeps/x86_64/configure.ac: Likewise.
* sysdeps/i386/configure: Regenerated.
* sysdeps/x86_64/configure: Likewise.
* sysdeps/mips/Makefile (ASFLAGS-.o): Add $(pie-default).
(ASFLAGS-.op): Likewise.
There is a configure option --without-fp that specifies that nofpu
sysdeps directories should be used instead of fpu directories.
For most glibc configurations, this option is of no use: either there
is no valid nofpu variant of that configuration, or there are no fpu
or nofpu sysdeps directories for that processor and so the option does
nothing. For a few configurations, if you are using a soft-float
compiler this option is required, and failing to use it generally
results in compilation errors from inline asm using unavailable
floating-point instructions.
We're moving away from --with-cpu to configuring glibc based on how
the compiler generates code, and it is natural to do so for
--without-fp as well; in most cases the soft-float and hard-float ABIs
are incompatible so you have no hope of building a working glibc with
an inappropriately configured compiler or libgcc.
This patch eliminates --without-fp, replacing it entirely by automatic
configuration based on the compiler. Configurations for which this is
relevant (coldfire / mips / powerpc32 / sh) define a variable
with_fp_cond in their preconfigure fragments (under the same
conditions under which those fragments do anything); this is a
preprocessor conditional which the toplevel configure script then uses
in a test to determine which sysdeps directories to use.
The config.make with-fp variable remains. It's used only by powerpc
(sysdeps/powerpc/powerpc32/Makefile) to add -mhard-float to various
flags variables. For powerpc, -mcpu= options can imply use of
soft-float. That could be an issue if you want to build for
e.g. 476fp, but are using --with-cpu=476 because there isn't a 476fp
sysdeps directory. If in future we eliminate --with-cpu and replace
it entirely by testing the compiler, it would be natural at that point
to eliminate that code as well (as the user should then just use a
compiler defaulting to 476fp and the 476 sysdeps directory would be
used automatically).
Tested for x86_64, and tested with build-many-glibcs.py that installed
shared libraries are unchanged by this patch.
* configure.ac (--with-fp): Remove configure option.
(with_fp_cond): New variable.
(libc_cv_with_fp): New configure test. Use this variable instead
of with_fp.
* configure: Regenerated.
* config.make.in (with-fp): Use @libc_cv_with_fp@.
* manual/install.texi (Configuring and compiling): Remove
--without-fp.
* INSTALL: Regenerated.
* sysdeps/m68k/preconfigure (with_fp_cond): Define for ColdFire.
* sysdeps/mips/preconfigure (with_fp_cond): Define.
* sysdeps/powerpc/preconfigure (with_fp_cond): Define for 32-bit.
* sysdeps/sh/preconfigure (with_fp_cond): Define.
* scripts/build-many-glibcs.py (Context.add_all_configs): Do not
use --without-fp to configure glibc.
On POWER8, unaligned memory accesses to cached memory has little impact
on performance as opposed to its ancestors.
It is disabled by default and will only be available when the tunable
glibc.tune.cached_memopt is set to 1.
__memcpy_power8_cached __memcpy_power7
============================================================
max-size=4096: 33325.70 ( 12.65%) 38153.00
max-size=8192: 32878.20 ( 11.17%) 37012.30
max-size=16384: 33782.20 ( 11.61%) 38219.20
max-size=32768: 33296.20 ( 11.30%) 37538.30
max-size=65536: 33765.60 ( 10.53%) 37738.40
* manual/tunables.texi (Hardware Capability Tunables): Document
glibc.tune.cached_memopt.
* sysdeps/powerpc/cpu-features.c: New file.
* sysdeps/powerpc/cpu-features.h: New file.
* sysdeps/powerpc/dl-procinfo.c [!IS_IN(ldconfig)]: Add
_dl_powerpc_cpu_features.
* sysdeps/powerpc/dl-tunables.list: New file.
* sysdeps/powerpc/ldsodefs.h: Include cpu-features.h.
* sysdeps/powerpc/powerpc32/power4/multiarch/init-arch.h
(INIT_ARCH): Initialize use_aligned_memopt.
* sysdeps/powerpc/powerpc64/dl-machine.h [defined(SHARED &&
IS_IN(rtld))]: Restrict dl_platform_init availability and
initialize CPU features used by tunables.
* sysdeps/powerpc/powerpc64/multiarch/Makefile (sysdep_routines):
Add memcpy-power8-cached.
* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c: Add
__memcpy_power8_cached.
* sysdeps/powerpc/powerpc64/multiarch/memcpy.c: Likewise.
* sysdeps/powerpc/powerpc64/multiarch/memcpy-power8-cached.S:
New file.
Reviewed-by: Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
