[libc][POSIX][poll.h] implement poll

Simple syscall.

Fixes: #124647

Author: nickdesaulniers

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/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()

libc/include/llvm-libc-macros/CMakeLists.txt

@@ -321,3 +321,9 @@ add_macro_header(
   HDR
     pthread-macros.h
 )
+
+add_macro_header(
+  poll-macros
+  HDR
+    poll-macros.h
+)

libc/include/llvm-libc-macros/linux/CMakeLists.txt

@@ -10,6 +10,12 @@ add_header(
     fcntl-macros.h
 )
 
+add_header(
+  poll-macros
+  HDR
+    poll-macros.h
+)
+
 add_header(
   sched_macros
   HDR

libc/include/llvm-libc-macros/linux/poll-macros.h

@@ -0,0 +1,65 @@
+//===-- Macros defined in poll.h header file ------------------------------===//
+//
+// 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_MACROS_LINUX_POLL_MACROS_H
+#define LLVM_LIBC_MACROS_LINUX_POLL_MACROS_H
+
+// From asm-generic/poll.h, redefined here to avoid redeclaring struct pollfd.
+#ifndef POLLIN
+#define POLLIN          0x0001
+#endif
+
+#ifndef POLLPRI
+#define POLLPRI         0x0002
+#endif
+
+#ifndef POLLOUT
+#define POLLOUT         0x0004
+#endif
+
+#ifndef POLLERR
+#define POLLERR         0x0008
+#endif
+
+#ifndef POLLHUP
+#define POLLHUP         0x0010
+#endif
+
+#ifndef POLLNVAL
+#define POLLNVAL        0x0020
+#endif
+
+#ifndef POLLRDNORM
+#define POLLRDNORM      0x0040
+#endif
+
+#ifndef POLLRDBAND
+#define POLLRDBAND      0x0080
+#endif
+
+#ifndef POLLWRNORM
+#define POLLWRNORM      0x0100
+#endif
+
+#ifndef POLLWRBAND
+#define POLLWRBAND      0x0200
+#endif
+
+#ifndef POLLMSG
+#define POLLMSG         0x0400
+#endif
+
+#ifndef POLLREMOVE
+#define POLLREMOVE      0x1000
+#endif
+
+#ifndef POLLRDHUP
+#define POLLRDHUP       0x2000
+#endif
+
+#endif // LLVM_LIBC_MACROS_LINUX_POLL_MACROS_H

libc/include/llvm-libc-macros/poll-macros.h

@@ -0,0 +1,16 @@
+//===-- Macros defined in poll.h header file ------------------------------===//
+//
+// 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_MACROS_POLL_MACROS_H
+#define LLVM_LIBC_MACROS_POLL_MACROS_H
+
+#ifdef __linux__
+#include "linux/poll-macros.h"
+#endif
+
+#endif // LLVM_LIBC_MACROS_POLL_MACROS_H

libc/include/llvm-libc-types/CMakeLists.txt

@@ -44,6 +44,7 @@ add_header(jmp_buf HDR jmp_buf.h)
 add_header(mbstate_t HDR mbstate_t.h)
 add_header(mode_t HDR mode_t.h)
 add_header(mtx_t HDR mtx_t.h DEPENDS .__futex_word .__mutex_type)
+add_header(nfds_t HDR nfds_t.h)
 add_header(nlink_t HDR nlink_t.h)
 add_header(off_t HDR off_t.h)
 add_header(once_flag HDR once_flag.h DEPENDS .__futex_word)
@@ -67,14 +68,15 @@ else()
 endif()
 add_header(stack_t HDR stack_t.h DEPENDS .size_t)
 add_header(suseconds_t HDR suseconds_t.h)
+add_header(struct_dirent HDR struct_dirent.h DEPENDS .ino_t .off_t)
+add_header(struct_f_owner_ex HDR struct_f_owner_ex.h DEPENDS .pid_t)
 add_header(struct_flock HDR struct_flock.h DEPENDS .off_t .pid_t)
 add_header(struct_flock64 HDR struct_flock64.h DEPENDS .off64_t .pid_t)
-add_header(struct_f_owner_ex HDR struct_f_owner_ex.h DEPENDS .pid_t)
-add_header(struct_timeval HDR struct_timeval.h DEPENDS .suseconds_t .time_t)
+add_header(struct_pollfd HDR struct_pollfd.h)
 add_header(struct_rlimit HDR struct_rlimit.h DEPENDS .rlim_t)
-add_header(struct_rusage HDR struct_rusage.h DEPENDS .struct_timeval)
-add_header(struct_dirent HDR struct_dirent.h DEPENDS .ino_t .off_t)
 add_header(struct_sched_param HDR struct_sched_param.h)
+add_header(struct_timeval HDR struct_timeval.h DEPENDS .suseconds_t .time_t)
+add_header(struct_rusage HDR struct_rusage.h DEPENDS .struct_timeval)
 add_header(union_sigval HDR union_sigval.h)
 add_header(siginfo_t HDR siginfo_t.h DEPENDS .union_sigval .pid_t .uid_t .clock_t)
 add_header(sig_atomic_t HDR sig_atomic_t.h)