#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 */

/* Variables and functions */
int /*<<< orphan*/ execv(char *, char **);
int /*<<< orphan*/ perror(char *);
int /*<<< orphan*/ printf(char *);
int main(int argc, char **argv) {
  printf("Hello world!\n");
  char *args[] = {"ls", "-l", NULL};
  execv("/bin/ls", args);
  perror("execv");
  printf("Goodbye world!\n");
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
movl   $0x0,-0x4(%rbp)
mov    %edi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
lea    0xeb3(%rip),%rdi
call   1030 <printf@plt>
mov    0x2ca7(%rip),%rax
mov    %rax,-0x30(%rbp)
mov    0x2ca4(%rip),%rax
mov    %rax,-0x28(%rbp)
mov    0x2ca1(%rip),%rax
mov    %rax,-0x20(%rbp)
lea    -0x30(%rbp),%rsi
lea    0xe93(%rip),%rdi
call   1050 <execv@plt>
lea    0xe8f(%rip),%rdi
call   1040 <perror@plt>
lea    0xe89(%rip),%rdi
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
sub    $0x18,%rsp
lea    0xed6(%rip),%rdi
call   1030 <puts@plt>
mov    0x2cc9(%rip),%rax
mov    %rax,0x10(%rsp)
movaps 0x2cad(%rip),%xmm0
movaps %xmm0,(%rsp)
lea    0xea5(%rip),%rdi
mov    %rsp,%rsi
call   1050 <execv@plt>
lea    0xe9e(%rip),%rdi
call   1040 <perror@plt>
lea    0xea5(%rip),%rdi
call   1030 <puts@plt>
xor    %eax,%eax
add    $0x18,%rsp
ret

LLVM IR (-O0):
@.str = [14 x i8] c"Hello world!\0A\00"
@.str.1 = [3 x i8] c"ls\00"
@.str.2 = [3 x i8] c"-l\00"
@__const.main.args = [3 x i8*] [i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i32 0, i32 0), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i32 0, i32 0), i8* null]
@.str.3 = [8 x i8] c"/bin/ls\00"
@.str.4 = [6 x i8] c"execv\00"
@.str.5 = [16 x i8] c"Goodbye world!\0A\00"
define i32 @main(i32 %0, i8** %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i8**
%6 = alloca [3 x i8*]
store i32 0, i32* %3
store i32 %0, i32* %4
store i8** %1, i8*** %5
%7 = call i32 @printf(i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str, i64 0, i64 0))
%8 = bitcast [3 x i8*]* %6 to i8*
%9 = getelementptr inbounds [3 x i8*], [3 x i8*]* %6, i64 0, i64 0
%10 = call i32 @execv(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0), i8** %9)
%11 = call i32 @perror(i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str.4, i64 0, i64 0))
%12 = call i32 @printf(i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str.5, i64 0, i64 0))
ret i32 0
}

LLVM IR (-O2):
@.str.1 = [3 x i8] c"ls\00"
@.str.2 = [3 x i8] c"-l\00"
@__const.main.args = [3 x i8*] [i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i32 0, i32 0), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i32 0, i32 0), i8* null]
@.str.3 = [8 x i8] c"/bin/ls\00"
@.str.4 = [6 x i8] c"execv\00"
@str = [13 x i8] c"Hello world!\00"
@str.6 = [15 x i8] c"Goodbye world!\00"
define i32 @main(i32 %0, i8** nocapture readnone %1) {
%3 = alloca [3 x i8*]
%4 = tail call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([13 x i8], [13 x i8]* @str, i64 0, i64 0))
%5 = bitcast [3 x i8*]* %3 to i8*
%6 = getelementptr inbounds [3 x i8*], [3 x i8*]* %3, i64 0, i64 0
%7 = call i32 @execv(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0), i8** %6)
%8 = call i32 @perror(i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str.4, i64 0, i64 0))
%9 = call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @str.6, i64 0, i64 0))
ret i32 0
}