cosmopolitan/libc
Justine Tunney 957c61cbbf
Release Cosmopolitan v3.3
This change upgrades to GCC 12.3 and GNU binutils 2.42. The GNU linker
appears to have changed things so that only a single de-duplicated str
table is present in the binary, and it gets placed wherever the linker
wants, regardless of what the linker script says. To cope with that we
need to stop using .ident to embed licenses. As such, this change does
significant work to revamp how third party licenses are defined in the
codebase, using `.section .notice,"aR",@progbits`.

This new GCC 12.3 toolchain has support for GNU indirect functions. It
lets us support __target_clones__ for the first time. This is used for
optimizing the performance of libc string functions such as strlen and
friends so far on x86, by ensuring AVX systems favor a second codepath
that uses VEX encoding. It shaves some latency off certain operations.
It's a useful feature to have for scientific computing for the reasons
explained by the test/libcxx/openmp_test.cc example which compiles for
fifteen different microarchitectures. Thanks to the upgrades, it's now
also possible to use newer instruction sets, such as AVX512FP16, VNNI.

Cosmo now uses the %gs register on x86 by default for TLS. Doing it is
helpful for any program that links `cosmo_dlopen()`. Such programs had
to recompile their binaries at startup to change the TLS instructions.
That's not great, since it means every page in the executable needs to
be faulted. The work of rewriting TLS-related x86 opcodes, is moved to
fixupobj.com instead. This is great news for MacOS x86 users, since we
previously needed to morph the binary every time for that platform but
now that's no longer necessary. The only platforms where we need fixup
of TLS x86 opcodes at runtime are now Windows, OpenBSD, and NetBSD. On
Windows we morph TLS to point deeper into the TIB, based on a TlsAlloc
assignment, and on OpenBSD/NetBSD we morph %gs back into %fs since the
kernels do not allow us to specify a value for the %gs register.

OpenBSD users are now required to use APE Loader to run Cosmo binaries
and assimilation is no longer possible. OpenBSD kernel needs to change
to allow programs to specify a value for the %gs register, or it needs
to stop marking executable pages loaded by the kernel as mimmutable().

This release fixes __constructor__, .ctor, .init_array, and lastly the
.preinit_array so they behave the exact same way as glibc.

We no longer use hex constants to define math.h symbols like M_PI.
2024-02-20 13:27:59 -08:00
..
calls Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
crt Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
dlopen Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
elf more modeline errata (#1019) 2023-12-16 23:07:10 -05:00
fmt Add dontthrow attribute to most libc functions 2024-01-09 01:26:03 -08:00
integral Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
intrin Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
irq more modeline errata (#1019) 2023-12-16 23:07:10 -05:00
isystem Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
log Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
mem Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
nexgen32e Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
nt Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
proc Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
runtime Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
sock Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
stdio Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
str Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
sysv Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
testlib Make improvements 2024-02-12 10:23:00 -08:00
thread Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
time Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
tinymath Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
vga more modeline errata (#1019) 2023-12-16 23:07:10 -05:00
x Make improvements 2024-02-12 10:23:00 -08:00
ar.h Reduce header complexity 2023-11-28 14:39:42 -08:00
assert.h Add dontthrow attribute to most libc functions 2024-01-09 01:26:03 -08:00
atomic.h Optimize memory layout 2022-09-12 04:26:52 -07:00
BUILD.mk Fine tune OpenMP some more 2024-01-30 06:30:24 -08:00
complex.h libc headers: make <complex.h> work, add struct ipv6_mreq (#1100) 2024-02-05 17:22:56 -05:00
cosmo.h Make improvements 2024-02-12 10:23:00 -08:00
cxxabi.h libc: Fix __cxa_thread_atexit prototype (#1088) 2024-01-22 10:23:28 -08:00
dce.h Make improvements 2024-01-29 16:31:58 -08:00
dos.internal.h Introduce #include <cosmo.h> to toolchain users 2023-06-09 18:03:05 -07:00
empty.s Do some basic build tuning 2023-05-10 04:20:46 -07:00
errno.h Reduce header complexity 2023-11-28 14:39:42 -08:00
imag.internal.h Remove evil constants from cosmopolitan.h 2022-12-17 00:42:45 -08:00
inttypes.h Fix issues for latest GCC toolchain 2023-10-11 14:54:42 -07:00
iso646.internal.h Add more missing C / C++ headers 2022-09-04 04:53:52 -07:00
limits.h Make improvements 2023-10-08 08:59:53 -07:00
literal.h Get GNU MPFR and MPC tests to pass 2023-08-21 15:05:10 -07:00
mach.internal.h Reduce header complexity 2023-11-28 14:39:42 -08:00
macho.internal.h Fiddle around with Mach-O 2023-05-20 04:13:49 -07:00
macros.internal.h Make improvements 2024-02-12 10:23:00 -08:00
math.h Release Cosmopolitan v3.3 2024-02-20 13:27:59 -08:00
paths.h Embed cocmd.com interpreter for system() / open() 2022-10-02 15:29:57 -07:00
README.md
serialize.h Reduce header complexity 2023-11-28 14:39:42 -08:00
stdalign.internal.h Add more missing C / C++ headers 2022-09-04 04:53:52 -07:00
stdbool.h Make improvements 2024-02-12 10:23:00 -08:00
stdckdint.h Reduce header complexity 2023-11-28 14:39:42 -08:00
stdlib.h Add dontthrow attribute to most libc functions 2024-01-09 01:26:03 -08:00
temp.h Add dontthrow attribute to most libc functions 2024-01-09 01:26:03 -08:00
testlib-test.txt Fix some zipos directory related bugs 2023-09-19 02:30:42 -07:00
type2str.h Improve new C23 checked arithmetic feature 2023-06-16 15:32:18 -07:00
zip.internal.h Add dontthrow attribute to most libc functions 2024-01-09 01:26:03 -08:00

Cosmopolitan Standard Library

This directory defines static archives defining functions, like printf(), mmap(), win32, etc. Please note that the Cosmopolitan build configuration doesn't link any C/C++ library dependencies by default, so you still have the flexibility to choose the one provided by your system. If you'd prefer Cosmopolitan, just add $(LIBC) and $(CRT) to your linker arguments.

Your library is compromised of many bite-sized static archives. We use the checkdeps tool to guarantee that the contents of the archives are organized in a logical way that's easy to use with or without our makefile infrastructure, since there's no cyclic dependencies.

The Cosmopolitan Library exports only the most stable canonical system calls for all supported operating systems, regardless of which platform is used for compilation. We polyfill many of the APIs, e.g. read(), write() so they work consistently everywhere while other apis, e.g. CreateWindowEx(), might only work on one platform, in which case they become no-op functions on others.

Cosmopolitan polyfill wrappers will usually use the dollar sign naming convention, so they may be bypassed when necessary. This same convention is used when multiple implementations of string library and other performance-critical function are provided to allow Cosmopolitan to go fast on both old and newer computers.

We take an approach to configuration that relies heavily on the compiler's dead code elimination pass (libc/dce.h). Most of the code is written so that, for example, folks not wanting support for OpenBSD can flip a bit in SUPPORT_VECTOR and that code will be omitted from the build. The same is true for builds that are tuned using -march=native which effectively asks the library to not include runtime support hooks for x86 processors older than what you use.

Please note that, unlike Cygwin or MinGW, Cosmopolitan does not achieve broad support by bolting on a POSIX emulation layer. We do nothing more than (in most cases) stateless API translations that get you 90% of the way there in a fast lightweight manner. We therefore can't address some of the subtle differences, such as the nuances of absolute paths on Windows. Our approach could be compared to something more along the lines of, "the Russians just used a pencil to write in space", versus spending millions researching a pen like NASA.