Some implementations in sysdeps/powerpc/powerpc64/power8/*.S still had
pre power8 compatible binutils hardcoded macros and were not using
.machine power8.
This patch should not have semantic changes, in fact it should have the
same exact code generated.
Tested that generated stripped shared objects are identical when
using "strip --remove-section=.note.gnu.build-id".
Checked on:
- powerpc64le, power9, build-many-glibcs.py, gcc 6.4.1 20180104, binutils 2.26.2.20160726
- powerpc64le, power8, debian 9, gcc 6.3.0 20170516, binutils 2.28
- powerpc64le, power9, ubuntu 19.04, gcc 8.3.0, binutils 2.32
- powerpc64le, power9, opensuse tumbleweed, gcc 9.1.1 20190527, binutils 2.32
- powerpc64, power9, debian 10, gcc 8.3.0, binutils 2.31.1
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Gabriel F. T. Gomes <gabrielftg@linux.ibm.com>
cfi info for stack adjust needs to be on the insn doing the adjust.
cfi describing register saves can be anywhere after the save insn but
before the reg is altered. Fewer locations with cfi result in smaller
cfi programs and possibly slightly faster exception handling. Thus
the LR cfi_offset move.
The idea behind ajusting sp after restoring regs is to break a
register dependency chain, in this case not be using r1 immediately
after it is modified.
The missing LR cfi_restore meant that code after the blr,
unaligned_lt_16 and other labels, would have cfi that said LR was at
cfa+16, but that code is reached without LR being saved.
* sysdeps/powerpc/powerpc64/power8/strncpy.S: Move LR cfi.
Adjust stack after restoring regs. Add missing LR cfi_restore.
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
Makes __stpncpy_power8 call __memset_power8 directly rather than via an
IFUNC. Fixes a missing _mcount, and removes some redundant NOPS. The
*_is_local defines are also used in a followup patch.
* sysdeps/powerpc/powerpc64/multiarch/strncpy-power7.S: Define
MEMSET_is_local.
* sysdeps/powerpc/powerpc64/multiarch/strncpy-power8.S: Likewise.
* sysdeps/powerpc/powerpc64/multiarch/stpncpy-power7.S: Likewise.
* sysdeps/powerpc/powerpc64/multiarch/stpncpy-power8.S: Likewise.
Define MEMSET.
* sysdeps/powerpc/powerpc64/multiarch/strstr-power7.S: Define
STRLEN_is_local, STRNLEN_is_local, and STRCHR_is_local.
* sysdeps/powerpc/powerpc64/power7/strstr.S: Likewise. Don't add
nop after local calls.
* sysdeps/powerpc/powerpc64/power7/strncpy.S: Define MEMSET_is_local.
Don't add nop after local call.
* sysdeps/powerpc/powerpc64/power8/strncpy.S: Likewise. Add missing
CALL_MCOUNT.
Clean up the IFUNC implementations for powerpc in order to remove
unneeded macro definitions.
Tested on ppc64le with and without --disable-multi-arch flag.
* sysdeps/powerpc/powerpc64/multiarch/stpcpy-power8.S: Define the
implementation-specific function name and remove unneeded macros
definition.
* sysdeps/powerpc/powerpc64/multiarch/stpncpy-power7.S: Likewise.
* sysdeps/powerpc/powerpc64/multiarch/stpncpy-power8.S: Likewise.
* sysdeps/powerpc/powerpc64/multiarch/strcpy-power8.S: Likewise.
* sysdeps/powerpc/powerpc64/multiarch/strncpy-power7.S: Likewise.
* sysdeps/powerpc/powerpc64/multiarch/strncpy-power8.S: Likewise.
* sysdeps/powerpc/powerpc64/power7/strncpy.S: Set a default
function name if not defined.
* sysdeps/powerpc/powerpc64/power8/strcpy.S: Likewise.
* sysdeps/powerpc/powerpc64/power8/strncpy.S: Likewise.
The file sysdeps/powerpc/sysdeps.h defines aliases for condition register
operands. E.g.: 'cr7' means condition register 7. On the one hand, this
increases readability, as it makes it easier for readers to know whether the
operand is a condition register, a general purpose register or an immediate.
On the other hand, this permits that condition registers be written as if they
were general purpose, and vice-versa, thus reducing the readability of the
code.
This commit removes some of these unintentional misuses.
The changes have no effect on the final code. Checked with objdump.
Call __memset_power8 to pad, with zeros, the remaining bytes in the
dest string on __strncpy_power8 and __stpncpy_power8. This improves
performance when n is larger than the input string, giving ~30% gain for
larger strings without impacting much shorter strings.
The file sysdeps/powerpc/sysdeps.h defines aliases for register operands,
which add the letter 'r' as a prefix to a register name. E.g.: register 20
can be written as 'r20', instead of '20'. On the one hand, this increases
readability, as it makes it easier for readers to know whether the operand is a
register or an immediate. On the other hand, this permits that immediate
operands be written as if they were registers, and vice-versa, thus reducing
the readability of the code.
This commit removes some of these unintentional misuses.
This commit also increases readability of the code by adding the prefix 'cr' to
some uses of the control register.
Both changes have no effect on the final code. Checked with objdump.
* sysdeps/powerpc/powerpc64/power8/strncpy.S: Remove or add register
prefix from operands.
This patch adds an optimized POWER8 st{r,p}ncpy using unaligned accesses.
It shows 10%-80% improvement over the optimized POWER7 one that uses
only aligned accesses, specially on unaligned inputs.
The algorithm first read and check 16 bytes (if inputs do not cross a 4K
page size). The it realign source to 16-bytes and issue a 16 bytes read
and compare loop to speedup null byte checks for large strings. Also,
different from POWER7 optimization, the null pad is done inline in the
implementation using possible unaligned accesses, instead of realying on
a memset call. Special case is added for page cross reads.
