[libc] Migrate to using LIBC_NAMESPACE_DECL for namespace declaration (#98597)

This is a part of #97655.

Revert "[libc] Migrate to using LIBC_NAMESPACE_DECL for namespace declaration" (#98593)

Reverts llvm/llvm-project#98075

bots are broken

[libc] Migrate to using LIBC_NAMESPACE_DECL for namespace declaration (#98075)

This is a part of #97655.

[libc] Codify header inclusion policy (#87017)


When supporting "overlay" vs "fullbuild" modes, "what ABI are you
using?" becomes a fundamental question to have concrete answers for.
Overlay mode MU

[libc] Codify header inclusion policy (#87017)


When supporting "overlay" vs "fullbuild" modes, "what ABI are you
using?" becomes a fundamental question to have concrete answers for.
Overlay mode MUST match the ABI of the system being overlayed onto;
fullbuild more flexible (the only system ABI relevant is the OS kernel).

When implementing llvm-libc we generally prefer the include-what-you use
style of avoiding transitive dependencies (since that makes refactoring
headers more painful, and slows down build times). So what header do you
include for any given type or function declaration? For any given
userspace program, the answer is straightforward. But for llvm-libc
which is trying to support multiple ABIs (at least one per
configuration), the answer is perhaps less clear.

This proposal seeks to add one layer of indirection relative to what's
being done today.

It then converts users of sigset_t and struct epoll_event and the epoll
implemenations over to this convention as an example.

show more ...

[libc] Mass replace enclosing namespace (#67032)

This is step 4 of
https://discourse.llvm.org/t/rfc-customizable-namespace-to-allow-testing-the-libc-when-the-system-libc-is-also-llvms-libc/73079

[libc][cleanup] Fix most conversion warnings

This patch is large, but is almost entirely just adding casts to calls
to syscall_impl. Much of the work was done programatically, with human
checking wh

[libc][cleanup] Fix most conversion warnings

This patch is large, but is almost entirely just adding casts to calls
to syscall_impl. Much of the work was done programatically, with human
checking when the syntax or types got confusing.

Reviewed By: mcgrathr

Differential Revision: https://reviews.llvm.org/D156950

show more ...

[libc] Add support to compile some syscalls on 32 bit platform

This patch adds a bunch of ifdefs to handle the 32 bit versions of
some syscalls, which often only append a 64 to the name of the sysca

[libc] Add support to compile some syscalls on 32 bit platform

This patch adds a bunch of ifdefs to handle the 32 bit versions of
some syscalls, which often only append a 64 to the name of the syscall
(with exception of SYS_lseek -> SYS_llseek and SYS_futex ->
SYS_futex_time64)

This patch also tries to handle cases where wait4 is not available
(as in riscv32): to implement wait, wait4 and waitpid when wait4 is
not available, we check for alternative wait calls and ultimately rely
on waitid to implement them all.

In riscv32, only waitid is available, so we need it to support this
platform.

Reviewed By: michaelrj

Differential Revision: https://reviews.llvm.org/D148371

show more ...

[libc][NFC] Switch use of errno in src/unistd and src/sys to libc_errno.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D145096

[libc] Add select.h and the implementation of the select function for Linux.

Reviewed By: michaelrj

Differential Revision: https://reviews.llvm.org/D136375