[libc][POSIX][poll.h] implement poll (#125118)

Simple syscall.

Fixes: #124647

Author: nickdesaulniers

libc/config/linux/aarch64/entrypoints.txt

@@ -32,6 +32,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.fcntl.open
     libc.src.fcntl.openat
 
+    # poll.h entrypoints
+    libc.src.poll.poll
+
     # sched.h entrypoints
     libc.src.sched.sched_get_priority_max
     libc.src.sched.sched_get_priority_min

libc/config/linux/aarch64/headers.txt

@@ -8,30 +8,31 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.features
     libc.include.fenv
     libc.include.float
-    libc.include.stdint
     libc.include.inttypes
     libc.include.limits
     libc.include.link
     libc.include.malloc
     libc.include.math
+    libc.include.poll
     libc.include.pthread
+    libc.include.search
     libc.include.signal
-    libc.include.stdckdint
     libc.include.stdbit
+    libc.include.stdckdint
+    libc.include.stdint
     libc.include.stdio
     libc.include.stdlib
     libc.include.string
     libc.include.strings
-    libc.include.search
     libc.include.sys_mman
     libc.include.sys_socket
     libc.include.sys_syscall
     libc.include.sys_time
     libc.include.threads
     libc.include.time
+    libc.include.uchar
     libc.include.unistd
     libc.include.wchar
-    libc.include.uchar
 
     libc.include.sys_ioctl
     # Disabled due to epoll_wait syscalls not being available on this platform.

libc/config/linux/arm/entrypoints.txt

@@ -20,6 +20,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     # errno.h entrypoints
     libc.src.errno.errno
 
+    # poll.h entrypoints
+    libc.src.poll.poll
+
     # string.h entrypoints
     libc.src.string.memccpy
     libc.src.string.memchr

libc/config/linux/riscv/entrypoints.txt

@@ -32,6 +32,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.fcntl.open
     libc.src.fcntl.openat
 
+    # poll.h entrypoints
+    libc.src.poll.poll
+
     # sched.h entrypoints
     libc.src.sched.sched_get_priority_max
     libc.src.sched.sched_get_priority_min

libc/config/linux/x86_64/entrypoints.txt

@@ -32,6 +32,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.fcntl.open
     libc.src.fcntl.openat
 
+    # poll.h entrypoints
+    libc.src.poll.poll
+
     # sched.h entrypoints
     libc.src.sched.sched_get_priority_max
     libc.src.sched.sched_get_priority_min

libc/config/linux/x86_64/headers.txt

@@ -1,4 +1,5 @@
 set(TARGET_PUBLIC_HEADERS
+    libc.include.arpa_inet
     libc.include.assert
     libc.include.complex
     libc.include.ctype
@@ -10,35 +11,27 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.features
     libc.include.fenv
     libc.include.float
-    libc.include.stdint
     libc.include.inttypes
     libc.include.limits
     libc.include.link
+    libc.include.locale
     libc.include.malloc
     libc.include.math
+    libc.include.poll
     libc.include.pthread
     libc.include.sched
+    libc.include.search
+    libc.include.setjmp
     libc.include.signal
     libc.include.spawn
-    libc.include.setjmp
-    libc.include.stdckdint
     libc.include.stdbit
+    libc.include.stdckdint
     libc.include.stdfix
+    libc.include.stdint
     libc.include.stdio
     libc.include.stdlib
     libc.include.string
     libc.include.strings
-    libc.include.search
-    libc.include.termios
-    libc.include.threads
-    libc.include.time
-    libc.include.unistd
-    libc.include.wchar
-    libc.include.uchar
-    libc.include.locale
-
-    libc.include.arpa_inet
-
     libc.include.sys_auxv
     libc.include.sys_epoll
     libc.include.sys_ioctl
@@ -56,4 +49,10 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.sys_types
     libc.include.sys_utsname
     libc.include.sys_wait
+    libc.include.termios
+    libc.include.threads
+    libc.include.time
+    libc.include.uchar
+    libc.include.unistd
+    libc.include.wchar
 )

libc/hdr/types/CMakeLists.txt

@@ -342,3 +342,19 @@ add_proxy_header_library(
     libc.include.llvm-libc-types.struct_iovec
     libc.include.sys_uio
 )
+
+add_proxy_header_library(
+  nfds_t
+  HDRS
+    nfds_t.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.nfds_t
+)
+
+add_proxy_header_library(
+  struct_pollfd
+  HDRS
+    struct_pollfd.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.struct_pollfd
+)

libc/hdr/types/nfds_t.h

@@ -0,0 +1,23 @@
+//===-- Definition of nfds_t ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_HDR_TYPES_NFDS_T_H
+#define LLVM_LIBC_HDR_TYPES_NFDS_T_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/nfds_t.h"
+
+#else // overlay mode
+
+#include <poll.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_NFDS_T_H

libc/hdr/types/struct_pollfd.h

@@ -0,0 +1,23 @@
+//===-- Definition of struct pollfd ---------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_HDR_TYPES_STRUCT_POLLFD_H
+#define LLVM_LIBC_HDR_TYPES_STRUCT_POLLFD_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/struct_pollfd.h"
+
+#else // overlay mode
+
+#include <poll.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_STRUCT_POLLFD_H

libc/include/CMakeLists.txt

@@ -704,6 +704,16 @@ add_header_macro(
     .llvm-libc-types.struct_lconv
 )
 
+add_header_macro(
+  poll
+  ../libc/include/poll.yaml
+  poll.h
+  DEPENDS
+    .llvm-libc-types.struct_pollfd
+    .llvm-libc-types.nfds_t
+    .llvm-libc-macros.poll-macros
+  )
+
 if(NOT LLVM_LIBC_FULL_BUILD)
   # We don't install headers in non-fullbuild mode.
   return()