#define NULL ((void *)0)
typedef unsigned long size_t; // Customize by platform.
typedef long intptr_t;
typedef unsigned long uintptr_t;
typedef long scalar_t__; // Either arithmetic or pointer type.
/* By default, we understand bool (as a convenience). */
typedef int bool;
#define false 0
#define true 1

/* Forward declarations */
typedef struct TYPE_2__ TYPE_1__;

/* Type definitions */
struct TYPE_2__ {
  int /*<<< orphan*/ s_addr;
};
struct sockaddr_in {
  int /*<<< orphan*/ sin_port;
  TYPE_1__ sin_addr;
  int /*<<< orphan*/ sin_family;
};
struct sockaddr {
  int dummy;
};
typedef int /*<<< orphan*/ serveraddr;

/* Variables and functions */
int /*<<< orphan*/ AF_INET;
int /*<<< orphan*/ INADDR_ANY;
int /*<<< orphan*/ SOCK_STREAM;
int /*<<< orphan*/ SOL_SOCKET;
int /*<<< orphan*/ SO_REUSEADDR;
int /*<<< orphan*/ bind(int, struct sockaddr *, int);
int /*<<< orphan*/ htonl(int /*<<< orphan*/);
int /*<<< orphan*/ htons(unsigned short);
int /*<<< orphan*/ listen(int, int);
int /*<<< orphan*/ memset(char *, int /*<<< orphan*/, int);
int /*<<< orphan*/ setsockopt(int, int /*<<< orphan*/, int /*<<< orphan*/,
                              void const *, int);
int socket(int /*<<< orphan*/, int /*<<< orphan*/, int /*<<< orphan*/);
int open_listenfd(int port) {
  int listenfd, option_value = 1;
  struct sockaddr_in serveraddr;
  listenfd = socket(AF_INET, SOCK_STREAM, 0);
  setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, (const void *)&option_value,
             sizeof(int));
  memset((char *)&serveraddr, 0, sizeof(serveraddr));
  serveraddr.sin_family = AF_INET;
  serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
  serveraddr.sin_port = htons((unsigned short)port);
  bind(listenfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr));
  listen(listenfd, 1024);
  return listenfd;
}


x86 assembly (clang, -O0):
<open_listenfd>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %edi,-0x4(%rbp)
movl   $0x1,-0xc(%rbp)
mov    0x2e57(%rip),%rax
mov    (%rax),%edi
mov    0x2e36(%rip),%rax
mov    (%rax),%esi
xor    %edx,%edx
call   1090 <socket@plt>
mov    %eax,-0x8(%rbp)
mov    -0x8(%rbp),%edi
mov    0x2e40(%rip),%rax
mov    (%rax),%esi
mov    0x2e0f(%rip),%rax
mov    (%rax),%edx
lea    -0xc(%rbp),%rcx
mov    $0x4,%r8d
call   1030 <setsockopt@plt>
lea    -0x18(%rbp),%rdi
xor    %esi,%esi
mov    $0xc,%edx
call   1060 <memset@plt>
mov    0x2e07(%rip),%rax
mov    (%rax),%eax
mov    %eax,-0x10(%rbp)
mov    0x2df3(%rip),%rax
mov    (%rax),%edi
call   1050 <htonl@plt>
mov    %eax,-0x14(%rbp)
mov    -0x4(%rbp),%eax
movzwl %ax,%edi
call   1040 <htons@plt>
mov    %eax,-0x18(%rbp)
mov    -0x8(%rbp),%edi
lea    -0x18(%rbp),%rsi
mov    $0xc,%edx
call   1080 <bind@plt>
mov    -0x8(%rbp),%edi
mov    $0x400,%esi
call   1070 <listen@plt>
mov    -0x8(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<open_listenfd>:
push   %rbp
push   %r15
push   %r14
push   %rbx
sub    $0x18,%rsp
mov    %edi,%r14d
movl   $0x1,0x4(%rsp)
mov    0x2e54(%rip),%r15
mov    (%r15),%edi
mov    0x2e32(%rip),%rax
mov    (%rax),%esi
xor    %edx,%edx
call   1090 <socket@plt>
mov    %eax,%ebx
mov    0x2e40(%rip),%rax
mov    (%rax),%esi
mov    0x2e0f(%rip),%rax
mov    (%rax),%edx
lea    0x4(%rsp),%rcx
mov    %ebx,%edi
mov    $0x4,%r8d
call   1030 <setsockopt@plt>
lea    0x8(%rsp),%rbp
mov    %rbp,%rdi
xor    %esi,%esi
mov    $0xc,%edx
call   1060 <memset@plt>
mov    (%r15),%eax
mov    %eax,0x10(%rsp)
mov    0x2df1(%rip),%rax
mov    (%rax),%edi
call   1050 <htonl@plt>
mov    %eax,0xc(%rsp)
movzwl %r14w,%edi
call   1040 <htons@plt>
mov    %eax,0x8(%rsp)
mov    %ebx,%edi
mov    %rbp,%rsi
mov    $0xc,%edx
call   1080 <bind@plt>
mov    %ebx,%edi
mov    $0x400,%esi
call   1070 <listen@plt>
mov    %ebx,%eax
add    $0x18,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
%struct.sockaddr_in = type { i32, %struct.TYPE_2__, i32 }
%struct.TYPE_2__ = type { i32 }
%struct.sockaddr = type { i32 }
@AF_INET = global i32 0
@SOCK_STREAM = global i32 0
@SOL_SOCKET = global i32 0
@SO_REUSEADDR = global i32 0
@INADDR_ANY = global i32 0
define i32 @open_listenfd(i32 %0) {
%2 = alloca i32
%3 = alloca i32
%4 = alloca i32
%5 = alloca %struct.sockaddr_in
store i32 %0, i32* %2
store i32 1, i32* %4
%6 = load i32, i32* @AF_INET
%7 = load i32, i32* @SOCK_STREAM
%8 = call i32 @socket(i32 %6, i32 %7, i32 0)
store i32 %8, i32* %3
%9 = load i32, i32* %3
%10 = load i32, i32* @SOL_SOCKET
%11 = load i32, i32* @SO_REUSEADDR
%12 = bitcast i32* %4 to i8*
%13 = call i32 @setsockopt(i32 %9, i32 %10, i32 %11, i8* %12, i32 4)
%14 = bitcast %struct.sockaddr_in* %5 to i8*
%15 = call i32 @memset(i8* %14, i32 0, i32 12)
%16 = load i32, i32* @AF_INET
%17 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %5, i32 0, i32 2
store i32 %16, i32* %17
%18 = load i32, i32* @INADDR_ANY
%19 = call i32 @htonl(i32 %18)
%20 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %5, i32 0, i32 1
%21 = getelementptr inbounds %struct.TYPE_2__, %struct.TYPE_2__* %20, i32 0, i32 0
store i32 %19, i32* %21
%22 = load i32, i32* %2
%23 = trunc i32 %22 to i16
%24 = call i32 @htons(i16 zeroext %23)
%25 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %5, i32 0, i32 0
store i32 %24, i32* %25
%26 = load i32, i32* %3
%27 = bitcast %struct.sockaddr_in* %5 to %struct.sockaddr*
%28 = call i32 @bind(i32 %26, %struct.sockaddr* %27, i32 12)
%29 = load i32, i32* %3
%30 = call i32 @listen(i32 %29, i32 1024)
%31 = load i32, i32* %3
ret i32 %31
}

LLVM IR (-O2):
%struct.sockaddr_in = type { i32, %struct.TYPE_2__, i32 }
%struct.TYPE_2__ = type { i32 }
%struct.sockaddr = type { i32 }
@AF_INET = global i32 0
@SOCK_STREAM = global i32 0
@SOL_SOCKET = global i32 0
@SO_REUSEADDR = global i32 0
@INADDR_ANY = global i32 0
define i32 @open_listenfd(i32 %0) {
%2 = alloca i32
%3 = alloca %struct.sockaddr_in
%4 = bitcast i32* %2 to i8*
store i32 1, i32* %2
%5 = bitcast %struct.sockaddr_in* %3 to i8*
%6 = load i32, i32* @AF_INET
%7 = load i32, i32* @SOCK_STREAM
%8 = tail call i32 @socket(i32 %6, i32 %7, i32 0)
%9 = load i32, i32* @SOL_SOCKET
%10 = load i32, i32* @SO_REUSEADDR
%11 = call i32 @setsockopt(i32 %8, i32 %9, i32 %10, i8* %4, i32 4)
%12 = call i32 @memset(i8* %5, i32 0, i32 12)
%13 = load i32, i32* @AF_INET
%14 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %3, i64 0, i32 2
store i32 %13, i32* %14
%15 = load i32, i32* @INADDR_ANY
%16 = call i32 @htonl(i32 %15)
%17 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %3, i64 0, i32 1, i32 0
store i32 %16, i32* %17
%18 = trunc i32 %0 to i16
%19 = call i32 @htons(i16 zeroext %18)
%20 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %3, i64 0, i32 0
store i32 %19, i32* %20
%21 = bitcast %struct.sockaddr_in* %3 to %struct.sockaddr*
%22 = call i32 @bind(i32 %8, %struct.sockaddr* %21, i32 12)
%23 = call i32 @listen(i32 %8, i32 1024)
ret i32 %8
}