APS5_SAMPLE_WORKER=<file> now also writes <file stem>.collapsed.txt: one
"frame;...;frame count" line per distinct stack of queue worker 0, root
first, frames as module+0xRVA, which speedscope.app and flamegraph.pl
open. Walks go up to 64 frames, and nothing allocates while the worker is
suspended.
The libraries are built with -fno-asynchronous-unwind-tables, so most of
their functions have no .pdata entry, only a DWARF record in .ehfram, and a
walk ended at the first such frame. The worker's walk now steps those
frames through their record, with the CIE/FDE decoding and the call frame
instructions of libc's unwinder, which move from Unwind.cpp into its
header unchanged. A module is indexed after the worker resumes, the first
time a walk meets it, and every register the step restores is read inside
the worker's stack. The process sampler (APS5_SAMPLE_THREADS) keeps its 12
frames through .pdata.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
qsort was a heapsort. It sorted correctly, but elements that compare
equal ended in a different order from FreeBSD's Bentley-McIlroy qsort,
in 18947 of 20000 random arrays with repeated keys, and below 7
elements, where FreeBSD's insertion sort keeps equal elements in
place, a heapsort does not. qsort now follows FreeBSD 11 qsort.c,
including its comparator call sequence.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VZWLdTjf1S57iLgn2rcaFb
The Windows unwinder stopped at the first frame of a module without the
project's .ehmeta or .ehfram tables, so an exception could not cross
libstdc++-6.dll and libwinpthread-1.dll (std::call_once through
pthread_once) or system DLLs. For such a frame it now looks up the
function's PE unwind data with RtlLookupFunctionEntry and takes the
caller's registers, including the nonvolatile rsi, rdi and xmm6-xmm15,
from RtlVirtualUnwind. A frame whose unwind data has an exception or
termination handler still stops the walk, since those handlers are not
run.
windows_exceptions gets back the std::call_once case of #1423.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Kart PS5 (PPSA99611, Phi1ow/mkwii-ps5 v1.0.0-rc1) stops on it right
after __divti3. The related open PR #4037 reports: "with this change it
passes `__divti3` and stops at `ELSr5qm4K1M` (`__umodti3`)".
PS5CEMU-HAR (PPSA99360) imports it too: tools/import_audit.py lists
ELSr5qm4K1M __umodti3 as absent from libSceLibcInternal.prx (registry
index 359), so the predicted stop is
"FAIL: unresolved ELF import ELSr5qm4K1M from libSceLibcInternal.prx".
libSceLibcInternal imports fall back to libc.prx, so the export lives in
libc beside __udivti3. compute_nid and aerolib (zecoxao/sce_symbols
2883963a) both give ELSr5qm4K1M = __umodti3.
__umodti3 is compiler-rt's lib/builtins/umodti3.c (llvm-project
0ee439b705e82a4fe20e266bc8fea96d0e60e1ec): the remainder that
__udivmodti4 leaves. The restoring division of SonyUdivti3 already
computes it, so the loop moves to SonyUdivmod128 and both helpers use
it. A zero divisor reaches a 64-bit divide in __udivmodti4 and traps on
x86-64; this throws instead, as __udivti3 does, and names the dividend.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
RetroArch 1.0.0-beta.1 (PPSA99169) stops on main 0f863c10 at
FAIL: unresolved ELF import Nx-F5v0-qU8 from libSceLibcInternal.prx
Nx-F5v0-qU8 is asinl (tools/nid_names.py, aerolib).
The implementation follows the asinl of the libc.prx bundled with
PPSA28319, read from its disassembly: FreeBSD msun's e_asinl.c with
the ld80 invtrig.c coefficients (9f043204), which the binary holds as
the same 80-bit constants, computed in the x87 long double the guest
uses. +-1 returns +-pi/2 rounded to 64 bits and +-0 keeps its sign.
For |x| > 1, the infinities and NaN, Sony's error helper raises
FE_INVALID and sets errno to EDOM before returning (x - x) / (x - x),
so a NaN argument sets EDOM too.
20 million random arguments in (-1, 1) plus the branch edges give the
same bits as that code from the title's libc.prx run on a Windows
host. guest_math pins a set of those bits and checks the domain
errors' errno and FE_INVALID, and that errno is untouched otherwise.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Ruffle Flash 1.2.0 (PPSA68091) stops on main 0f863c10 at
FAIL: unresolved ELF import 1t1-JoZ0sZQ from libSceLibcInternal.prx
1t1-JoZ0sZQ is sinhf (tools/nid_names.py, aerolib). RetroArch
1.0.0-beta.1 (PPSA99169) imports it as well.
The implementation follows the sinhf of the libc.prx bundled with
PPSA28319, read from its disassembly: FreeBSD msun's e_sinhf.c as of
5aa554c7 (before __ldexp_expf, so expf(|x| / 2) is squared between
logf(FLT_MAX) and the overflow threshold), calling msun stable/9
expm1f and expf (59bc2f09), whose paths for the arguments sinhf passes
are inlined. Past the threshold Sony's error helper sets errno to
ERANGE before returning x * 1e37; NaN and the infinities return x + x
and leave errno alone.
Running that code from the title's libc.prx on a Windows host gives
the same bits as this implementation for every finite argument up to
the threshold, both signs (2,238,032,378 inputs). guest_math pins a
set of those bits, the overflow errno and FE_OVERFLOW, and checks that
errno is untouched otherwise.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
On Linux sscanf, vsscanf, fscanf and sscanf_s hand their conversions to
glibc. Since glibc 2.38, code built as GNU C++ calls the C23 entry
points (__isoc23_vsscanf, __isoc23_vfscanf, __isoc23_sscanf), whose %i
reads a 0b/0B binary prefix. On main,
sscanf("0b101 x", "%i%n%7s", &value, &end, rest) stores value 5 and
end 5 and leaves "x" for the %s; " -0B11" gives -3. TechnicalDebt
records this.
FreeBSD's %i knows only the 0 and 0x prefixes. FreeBSD 11.4
lib/libc/stdio/vfscanf.c, parseint, lines 345-353 and 371-380:
case '0':
if (base == 0) {
base = 8;
flags |= PFXOK;
}
...
/* letters ok iff hex */
case 'A': case 'B': case 'C':
case 'D': case 'E': case 'F':
case 'a': case 'b': case 'c':
case 'd': case 'e': case 'f':
/* no need to fix base here */
if (base <= 10)
break; /* not legal here */
so "0b101" stores 0, consumes the "0" and leaves "b101", as C17 does
and as the strtol family here already does.
With glibc the scanf family now calls __isoc99_vsscanf and
__isoc99_vfscanf, the entry points GNU C++ used before glibc 2.38
(exported since 2.7), which read %i without the binary prefix. Other
hosts keep std::vsscanf and std::vfscanf. The TechnicalDebt entry is
removed.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
fflush() passed every stream to glibc's fflush(). For a stream that is
reading, glibc seeks the descriptor back and drops the read buffer, and
with a pushed-back character it gets the position wrong: after fgetc()
returned 'a' from "abcdef\n" and ungetc('Z'), fflush() returned 0 and
the next fread() returned "bcdef\n\n". The pushed-back 'Z' was lost and
the last byte came back twice.
FreeBSD's fflush() writes out only a stream that is writing and leaves
every other stream as it is, lib/libc/stdio/fflush.c:
if ((fp->_flags & (__SWR | __SRW)) == 0)
retval = 0;
else
retval = __sflush(fp);
and __sflush():
t = fp->_flags;
if ((t & __SWR) == 0)
return (0);
fflush() on Linux now returns 0 without calling the host for a stream
whose last operation was not a write (__fwriting() is 0). fflush(NULL)
and streams that are writing are unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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