#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 backtrace(void **, int);
char **backtrace_symbols(void **, int);
int /*<<< orphan*/ free(char **);
int /*<<< orphan*/ printf(char *, ...);
void foo() {
  int j, nptrs;
  void *buffer[100];
  char **strings;
  nptrs = backtrace(buffer, 100);
  printf("backtrace() return %d addresses \n", nptrs);
  strings = backtrace_symbols(buffer, nptrs);
  if (strings) {
    for (j = 0; j < nptrs; j++) {
      printf("%s \n", strings[j]);
    }
    free(strings);
  }
  printf("hello world\n");
  return;
}


x86 assembly (clang, -O0):
<foo>:
push   %rbp
mov    %rsp,%rbp
sub    $0x340,%rsp
lea    -0x330(%rbp),%rdi
mov    $0x64,%esi
call   1050 <backtrace@plt>
mov    %eax,-0x8(%rbp)
mov    -0x8(%rbp),%esi
lea    0xe97(%rip),%rdi
mov    $0x0,%al
call   1060 <printf@plt>
lea    -0x330(%rbp),%rdi
mov    -0x8(%rbp),%esi
call   1040 <backtrace_symbols@plt>
mov    %rax,-0x338(%rbp)
cmpq   $0x0,-0x338(%rbp)
je     11de <foo+0x9e>
movl   $0x0,-0x4(%rbp)
mov    -0x4(%rbp),%eax
cmp    -0x8(%rbp),%eax
jge    11d2 <foo+0x92>
mov    -0x338(%rbp),%rax
movslq -0x4(%rbp),%rcx
mov    (%rax,%rcx,8),%rsi
lea    0xe65(%rip),%rdi
mov    $0x0,%al
call   1060 <printf@plt>
mov    -0x4(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x4(%rbp)
jmp    119b <foo+0x5b>
mov    -0x338(%rbp),%rdi
call   1030 <free@plt>
lea    0xe42(%rip),%rdi
mov    $0x0,%al
call   1060 <printf@plt>
add    $0x340,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<foo>:
push   %rbp
push   %r15
push   %r14
push   %rbx
sub    $0x328,%rsp
mov    %rsp,%rbx
mov    %rbx,%rdi
mov    $0x64,%esi
call   1060 <backtrace@plt>
mov    %eax,%ebp
lea    0xe8a(%rip),%rdi
mov    %eax,%esi
xor    %eax,%eax
call   1070 <printf@plt>
mov    %rbx,%rdi
mov    %ebp,%esi
call   1050 <backtrace_symbols@plt>
test   %rax,%rax
je     11bf <foo+0x6f>
mov    %rax,%r15
test   %ebp,%ebp
jle    11b7 <foo+0x67>
mov    %ebp,%ebp
lea    0xe84(%rip),%r14
xor    %ebx,%ebx
mov    (%r15,%rbx,8),%rsi
mov    %r14,%rdi
xor    %eax,%eax
call   1070 <printf@plt>
add    $0x1,%rbx
cmp    %rbx,%rbp
jne    11a0 <foo+0x50>
mov    %r15,%rdi
call   1030 <free@plt>
lea    0xe61(%rip),%rdi
call   1040 <puts@plt>
add    $0x328,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
@.str = [34 x i8] c"backtrace() return %d addresses \0A\00"
@.str.1 = [5 x i8] c"%s \0A\00"
@.str.2 = [13 x i8] c"hello world\0A\00"
define void @foo() {
%1 = alloca i32
%2 = alloca i32
%3 = alloca [100 x i8*]
%4 = alloca i8**
%5 = getelementptr inbounds [100 x i8*], [100 x i8*]* %3, i64 0, i64 0
%6 = call i32 @backtrace(i8** %5, i32 100)
store i32 %6, i32* %2
%7 = load i32, i32* %2
%8 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([34 x i8], [34 x i8]* @.str, i64 0, i64 0), i32 %7)
%9 = getelementptr inbounds [100 x i8*], [100 x i8*]* %3, i64 0, i64 0
%10 = load i32, i32* %2
%11 = call i8** @backtrace_symbols(i8** %9, i32 %10)
store i8** %11, i8*** %4
%12 = load i8**, i8*** %4
%13 = icmp ne i8** %12, null
br i1 %13, label %14, label %32
14: ; preds = %0
store i32 0, i32* %1
br label %15
15: ; preds = %26, %14
%16 = load i32, i32* %1
%17 = load i32, i32* %2
%18 = icmp slt i32 %16, %17
br i1 %18, label %19, label %29
19: ; preds = %15
%20 = load i8**, i8*** %4
%21 = load i32, i32* %1
%22 = sext i32 %21 to i64
%23 = getelementptr inbounds i8*, i8** %20, i64 %22
%24 = load i8*, i8** %23
%25 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i8* %24)
br label %26
26: ; preds = %19
%27 = load i32, i32* %1
%28 = add nsw i32 %27, 1
store i32 %28, i32* %1
br label %15
29: ; preds = %15
%30 = load i8**, i8*** %4
%31 = call i32 @free(i8** %30)
br label %32
32: ; preds = %29, %0
%33 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str.2, i64 0, i64 0))
ret void
}

LLVM IR (-O2):
@.str = [34 x i8] c"backtrace() return %d addresses \0A\00"
@.str.1 = [5 x i8] c"%s \0A\00"
@str = [12 x i8] c"hello world\00"
define void @foo() {
%1 = alloca [100 x i8*]
%2 = bitcast [100 x i8*]* %1 to i8*
%3 = getelementptr inbounds [100 x i8*], [100 x i8*]* %1, i64 0, i64 0
%4 = call i32 @backtrace(i8** %3, i32 100)
%5 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([34 x i8], [34 x i8]* @.str, i64 0, i64 0), i32 %4)
%6 = call i8** @backtrace_symbols(i8** %3, i32 %4)
%7 = icmp eq i8** %6, null
br i1 %7, label %21, label %8
8: ; preds = %0
%9 = icmp sgt i32 %4, 0
br i1 %9, label %10, label %19
10: ; preds = %8
%11 = zext i32 %4 to i64
br label %12
12: ; preds = %10, %12
%13 = phi i64 [ 0, %10 ], [ %17, %12 ]
%14 = getelementptr inbounds i8*, i8** %6, i64 %13
%15 = load i8*, i8** %14
%16 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i8* %15)
%17 = add nuw nsw i64 %13, 1
%18 = icmp eq i64 %17, %11
br i1 %18, label %19, label %12
19: ; preds = %12, %8
%20 = call i32 @free(i8** %6)
br label %21
21: ; preds = %19, %0
%22 = call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([12 x i8], [12 x i8]* @str, i64 0, i64 0))
ret void
}