#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 */

/* Type definitions */
typedef int /*<<< orphan*/ yes;
struct sockaddr_in {
  int /*<<< orphan*/ sin_family;
  int /*<<< orphan*/ sin_port;
};
struct sockaddr {
  int dummy;
};
typedef int /*<<< orphan*/ addr;

/* Variables and functions */
int /*<<< orphan*/ AF_INET;
int /*<<< orphan*/ SOCK_STREAM;
int /*<<< orphan*/ SOL_SOCKET;
int /*<<< orphan*/ SO_REUSEADDR;
int bind(int, struct sockaddr *, int);
int /*<<< orphan*/ close(int);
int /*<<< orphan*/ htons(int);
int /*<<< orphan*/ listen(int, int);
int /*<<< orphan*/ memset(struct sockaddr_in *, int /*<<< orphan*/, int);
int /*<<< orphan*/ perror(char *);
int /*<<< orphan*/ printf(char *, int);
int setsockopt(int, int /*<<< orphan*/, int /*<<< orphan*/, int *, int);
int socket(int /*<<< orphan*/, int /*<<< orphan*/, int /*<<< orphan*/);
int listen_socket(int listen_port) {
  struct sockaddr_in addr;
  int lfd;
  int yes;
  lfd = socket(AF_INET, SOCK_STREAM, 0);
  if (lfd == -1) {
    perror("socket");
    return -1;
  }
  yes = 1;
  if (setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) == -1) {
    perror("setsockopt");
    close(lfd);
    return -1;
  }
  memset(&addr, 0, sizeof(addr));
  addr.sin_port = htons(listen_port);
  addr.sin_family = AF_INET;
  if (bind(lfd, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
    perror("bind");
    close(lfd);
    return -1;
  }
  printf("accepting connections on port %d\n", listen_port);
  listen(lfd, 10);
  return lfd;
}


x86 assembly (clang, -O0):
<listen_socket>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %edi,-0x8(%rbp)
mov    0x2e3e(%rip),%rax
mov    (%rax),%edi
mov    0x2e25(%rip),%rax
mov    (%rax),%esi
xor    %edx,%edx
call   10b0 <socket@plt>
mov    %eax,-0x14(%rbp)
cmpl   $0xffffffff,-0x14(%rbp)
jne    11d9 <listen_socket+0x49>
lea    0xe38(%rip),%rdi
call   10a0 <perror@plt>
movl   $0xffffffff,-0x4(%rbp)
jmp    12b0 <listen_socket+0x120>
movl   $0x1,-0x18(%rbp)
mov    -0x14(%rbp),%edi
mov    0x2dfe(%rip),%rax
mov    (%rax),%esi
mov    0x2dd5(%rip),%rax
mov    (%rax),%edx
lea    -0x18(%rbp),%rcx
mov    $0x4,%r8d
call   1030 <setsockopt@plt>
cmp    $0xffffffff,%eax
jne    122d <listen_socket+0x9d>
lea    0xdf3(%rip),%rdi
call   10a0 <perror@plt>
mov    -0x14(%rbp),%edi
call   1070 <close@plt>
movl   $0xffffffff,-0x4(%rbp)
jmp    12b0 <listen_socket+0x120>
lea    -0x10(%rbp),%rdi
xor    %esi,%esi
mov    $0x8,%edx
call   1060 <memset@plt>
mov    -0x8(%rbp),%edi
call   1040 <htons@plt>
mov    %eax,-0xc(%rbp)
mov    0x2d91(%rip),%rax
mov    (%rax),%eax
mov    %eax,-0x10(%rbp)
mov    -0x14(%rbp),%edi
lea    -0x10(%rbp),%rsi
mov    $0x8,%edx
call   1090 <bind@plt>
cmp    $0xffffffff,%eax
jne    128e <listen_socket+0xfe>
lea    0xd9d(%rip),%rdi
call   10a0 <perror@plt>
mov    -0x14(%rbp),%edi
call   1070 <close@plt>
movl   $0xffffffff,-0x4(%rbp)
jmp    12b0 <listen_socket+0x120>
mov    -0x8(%rbp),%esi
lea    0xd7f(%rip),%rdi
call   1050 <printf@plt>
mov    -0x14(%rbp),%edi
mov    $0xa,%esi
call   1080 <listen@plt>
mov    -0x14(%rbp),%eax
mov    %eax,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<listen_socket>:
push   %rbp
push   %r15
push   %r14
push   %rbx
sub    $0x18,%rsp
mov    %edi,%r14d
mov    0x2e3c(%rip),%r15
mov    (%r15),%edi
mov    0x2e22(%rip),%rax
mov    (%rax),%esi
xor    %edx,%edx
call   10b0 <socket@plt>
cmp    $0xffffffff,%eax
je     1256 <listen_socket+0xc6>
mov    %eax,%ebx
movl   $0x1,0xc(%rsp)
mov    0x2e17(%rip),%rax
mov    (%rax),%esi
mov    0x2dee(%rip),%rax
mov    (%rax),%edx
lea    0xc(%rsp),%rcx
mov    %ebx,%edi
mov    $0x4,%r8d
call   1030 <setsockopt@plt>
cmp    $0xffffffff,%eax
je     1269 <listen_socket+0xd9>
lea    0x10(%rsp),%rbp
mov    %rbp,%rdi
xor    %esi,%esi
mov    $0x8,%edx
call   1060 <memset@plt>
mov    %r14d,%edi
call   1040 <htons@plt>
mov    %eax,0x14(%rsp)
mov    (%r15),%eax
mov    %eax,0x10(%rsp)
mov    %ebx,%edi
mov    %rbp,%rsi
mov    $0x8,%edx
call   1090 <bind@plt>
cmp    $0xffffffff,%eax
je     1272 <listen_socket+0xe2>
lea    0xde2(%rip),%rdi
mov    %r14d,%esi
call   1050 <printf@plt>
mov    %ebx,%edi
mov    $0xa,%esi
call   1080 <listen@plt>
mov    %ebx,%eax
add    $0x18,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret
lea    0xda3(%rip),%rdi
call   10a0 <perror@plt>
mov    $0xffffffff,%ebx
jmp    1249 <listen_socket+0xb9>
lea    0xd97(%rip),%rdi
jmp    1279 <listen_socket+0xe9>
lea    0xd99(%rip),%rdi
call   10a0 <perror@plt>
mov    %ebx,%edi
call   1070 <close@plt>
mov    $0xffffffff,%ebx
jmp    1249 <listen_socket+0xb9>

LLVM IR (-O0):
%struct.sockaddr_in = type { i32, i32 }
%struct.sockaddr = type { i32 }
@AF_INET = global i32 0
@SOCK_STREAM = global i32 0
@.str = [7 x i8] c"socket\00"
@SOL_SOCKET = global i32 0
@SO_REUSEADDR = global i32 0
@.str.1 = [11 x i8] c"setsockopt\00"
@.str.2 = [5 x i8] c"bind\00"
@.str.3 = [34 x i8] c"accepting connections on port %d\0A\00"
define i32 @listen_socket(i32 %0) {
%2 = alloca i32
%3 = alloca i32
%4 = alloca %struct.sockaddr_in
%5 = alloca i32
%6 = alloca i32
store i32 %0, i32* %3
%7 = load i32, i32* @AF_INET
%8 = load i32, i32* @SOCK_STREAM
%9 = call i32 @socket(i32 %7, i32 %8, i32 0)
store i32 %9, i32* %5
%10 = load i32, i32* %5
%11 = icmp eq i32 %10, -1
br i1 %11, label %12, label %14
12: ; preds = %1
%13 = call i32 @perror(i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str, i64 0, i64 0))
store i32 -1, i32* %2
br label %45
14: ; preds = %1
store i32 1, i32* %6
%15 = load i32, i32* %5
%16 = load i32, i32* @SOL_SOCKET
%17 = load i32, i32* @SO_REUSEADDR
%18 = call i32 @setsockopt(i32 %15, i32 %16, i32 %17, i32* %6, i32 4)
%19 = icmp eq i32 %18, -1
br i1 %19, label %20, label %24
20: ; preds = %14
%21 = call i32 @perror(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.1, i64 0, i64 0))
%22 = load i32, i32* %5
%23 = call i32 @close(i32 %22)
store i32 -1, i32* %2
br label %45
24: ; preds = %14
%25 = call i32 @memset(%struct.sockaddr_in* %4, i32 0, i32 8)
%26 = load i32, i32* %3
%27 = call i32 @htons(i32 %26)
%28 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %4, i32 0, i32 1
store i32 %27, i32* %28
%29 = load i32, i32* @AF_INET
%30 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %4, i32 0, i32 0
store i32 %29, i32* %30
%31 = load i32, i32* %5
%32 = bitcast %struct.sockaddr_in* %4 to %struct.sockaddr*
%33 = call i32 @bind(i32 %31, %struct.sockaddr* %32, i32 8)
%34 = icmp eq i32 %33, -1
br i1 %34, label %35, label %39
35: ; preds = %24
%36 = call i32 @perror(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.2, i64 0, i64 0))
%37 = load i32, i32* %5
%38 = call i32 @close(i32 %37)
store i32 -1, i32* %2
br label %45
39: ; preds = %24
%40 = load i32, i32* %3
%41 = call i32 @printf(i8* getelementptr inbounds ([34 x i8], [34 x i8]* @.str.3, i64 0, i64 0), i32 %40)
%42 = load i32, i32* %5
%43 = call i32 @listen(i32 %42, i32 10)
%44 = load i32, i32* %5
store i32 %44, i32* %2
br label %45
45: ; preds = %39, %35, %20, %12
%46 = load i32, i32* %2
ret i32 %46
}

LLVM IR (-O2):
%struct.sockaddr_in = type { i32, i32 }
%struct.sockaddr = type { i32 }
@AF_INET = global i32 0
@SOCK_STREAM = global i32 0
@.str = [7 x i8] c"socket\00"
@SOL_SOCKET = global i32 0
@SO_REUSEADDR = global i32 0
@.str.1 = [11 x i8] c"setsockopt\00"
@.str.2 = [5 x i8] c"bind\00"
@.str.3 = [34 x i8] c"accepting connections on port %d\0A\00"
define i32 @listen_socket(i32 %0) {
%2 = alloca %struct.sockaddr_in
%3 = alloca i32
%4 = bitcast %struct.sockaddr_in* %2 to i8*
%5 = bitcast i32* %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 = icmp eq i32 %8, -1
br i1 %9, label %10, label %12
10: ; preds = %1
%11 = tail call i32 @perror(i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str, i64 0, i64 0))
br label %35
12: ; preds = %1
store i32 1, i32* %3
%13 = load i32, i32* @SOL_SOCKET
%14 = load i32, i32* @SO_REUSEADDR
%15 = call i32 @setsockopt(i32 %8, i32 %13, i32 %14, i32* %3, i32 4)
%16 = icmp eq i32 %15, -1
br i1 %16, label %17, label %20
17: ; preds = %12
%18 = call i32 @perror(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.1, i64 0, i64 0))
%19 = call i32 @close(i32 %8)
br label %35
20: ; preds = %12
%21 = call i32 @memset(%struct.sockaddr_in* %2, i32 0, i32 8)
%22 = call i32 @htons(i32 %0)
%23 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %2, i64 0, i32 1
store i32 %22, i32* %23
%24 = load i32, i32* @AF_INET
%25 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %2, i64 0, i32 0
store i32 %24, i32* %25
%26 = bitcast %struct.sockaddr_in* %2 to %struct.sockaddr*
%27 = call i32 @bind(i32 %8, %struct.sockaddr* %26, i32 8)
%28 = icmp eq i32 %27, -1
br i1 %28, label %29, label %32
29: ; preds = %20
%30 = call i32 @perror(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.2, i64 0, i64 0))
%31 = call i32 @close(i32 %8)
br label %35
32: ; preds = %20
%33 = call i32 @printf(i8* getelementptr inbounds ([34 x i8], [34 x i8]* @.str.3, i64 0, i64 0), i32 %0)
%34 = call i32 @listen(i32 %8, i32 10)
br label %35
35: ; preds = %32, %29, %17, %10
%36 = phi i32 [ -1, %10 ], [ -1, %17 ], [ -1, %29 ], [ %8, %32 ]
ret i32 %36
}