smart_ptr

#include <iostream>
#include <string>

// this can take a long time
void doOneThing() {
  // ...
}

// this can take a long time too
void doAnotherThing () {
  //...
}

int main(int argc, char** argv) {

  string mycool_str = "im a cool str\n"; // stl uses a smart pointers?

  doOneThing();

  doAnotherThing();

  return 0;

} // here the mycool_str will be deleted??


// compiled with g++
// decompiled with Radare2

/*
[0x000010b0]> pdf @ main
┌ 129: int main (int argc, char **argv, char **envp);
│           ; var char **var_60h @ rbp-0x60
│           ; var int64_t var_54h @ rbp-0x54
│           ; var int64_t var_41h @ rbp-0x41
│           ; var int64_t var_40h @ rbp-0x40
│           ; var int64_t var_18h @ rbp-0x18
│           ; arg int argc @ rdi
│           ; arg char **argv @ rsi
│           ; DATA XREF from entry0 @ 0x10d1
│           0x000011b7      55             push rbp
│           0x000011b8      4889e5         mov rbp, rsp
│           0x000011bb      53             push rbx
│           0x000011bc      4883ec58       sub rsp, 0x58
│           0x000011c0      897dac         mov dword [var_54h], edi    ; argc
│           0x000011c3      488975a0       mov qword [var_60h], rsi    ; argv
│           0x000011c7      64488b042528.  mov rax, qword fs:[0x28]
│           0x000011d0      488945e8       mov qword [var_18h], rax
│           0x000011d4      31c0           xor eax, eax
│           0x000011d6      488d45bf       lea rax, [var_41h]
│           0x000011da      4889c7         mov rdi, rax
│           0x000011dd      e8befeffff     call sym std::allocator<char>::allocator() ; sym.std::allocator_char_::allocator
│           0x000011e2      488d55bf       lea rdx, [var_41h]
│           0x000011e6      488d45c0       lea rax, [var_40h]
│           0x000011ea      488d35140e00.  lea rsi, str.im_a_cool_str  ; 0x2005 ; "im a cool str\n"
│           0x000011f1      4889c7         mov rdi, rax
│           0x000011f4      e877feffff     call sym std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&) ; sym.std::__cxx11::basic_string_char__std::char_traits_char___std::allocator_char___::basic_string_char_const___std::allocator_char__const
│           0x000011f9      488d45bf       lea rax, [var_41h]
│           0x000011fd      4889c7         mov rdi, rax
│           0x00001200      e84bfeffff     call sym std::allocator<char>::~allocator() ; sym.std::allocator_char_::_allocator
│           0x00001205      e89fffffff     call sym doOneThing()       ; sym.doOneThing
│           0x0000120a      e8a1ffffff     call sym doAnotherThing()   ; sym.doAnotherThing
│           0x0000120f      bb00000000     mov ebx, 0
│           0x00001214      488d45c0       lea rax, [var_40h]
│           0x00001218      4889c7         mov rdi, rax
│           0x0000121b      e810feffff     call sym std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string() ; sym.std::__cxx11::basic_string_char__std::char_traits_char___std::allocator_char___::_basic_string
│           0x00001220      89d8           mov eax, ebx
│           0x00001222      488b4de8       mov rcx, qword [var_18h]
│           0x00001226      6448330c2528.  xor rcx, qword fs:[0x28]
│       ┌─< 0x0000122f      7421           je 0x1252
└      ┌──< 0x00001231      eb1a           jmp loc.0000124d
*/

#include <iostream>
#include <string>

void doOneThing() {
  // ...
}

void doAnotherThing () {
  //...
}

int main(int argc, char** argv) {

  string* mycool_str = new std::string("im a cool str\n"); // needs manual delete, write?

  delete mycool_str; // delete the mycool_str

  doOneThing();

  doAnotherThing();

  return 0;

}

// compiled with g++
// decompiled with Radare2

/*
[0x000010d0]> pdf @ main
┌ 172: int main (int argc, char **argv, char **envp);
│           ; var char **var_40h @ rbp-0x40
│           ; var int64_t var_34h @ rbp-0x34
│           ; var int64_t var_21h @ rbp-0x21
│           ; var int64_t var_20h @ rbp-0x20
│           ; var int64_t canary @ rbp-0x18
│           ; arg int argc @ rdi
│           ; arg char **argv @ rsi
│           ; DATA XREF from entry0 @ 0x10f1
│           0x000011d7      55             push rbp
│           0x000011d8      4889e5         mov rbp, rsp
│           0x000011db      4154           push r12
│           0x000011dd      53             push rbx
│           0x000011de      4883ec30       sub rsp, 0x30
│           0x000011e2      897dcc         mov dword [var_34h], edi    ; argc
│           0x000011e5      488975c0       mov qword [var_40h], rsi    ; argv
│           0x000011e9      64488b042528.  mov rax, qword fs:[0x28]
│           0x000011f2      488945e8       mov qword [canary], rax
│           0x000011f6      31c0           xor eax, eax
│           0x000011f8      488d45df       lea rax, [var_21h]
│           0x000011fc      4889c7         mov rdi, rax
│           0x000011ff      e8bcfeffff     call sym std::allocator<char>::allocator() ; sym.std::allocator_char_::allocator
│           0x00001204      4c8d65df       lea r12, [var_21h]
│           0x00001208      bf20000000     mov edi, 0x20               ; "@"
│           0x0000120d      e83efeffff     call sym operator new(unsigned long) ; sym.operator_new_unsigned_long
│           0x00001212      4889c3         mov rbx, rax
│           0x00001215      4c89e2         mov rdx, r12
│           0x00001218      488d35e60d00.  lea rsi, str.im_a_cool_str  ; 0x2005 ; "im a cool str\n"
│           0x0000121f      4889df         mov rdi, rbx
│           0x00001222      e869feffff     call sym std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&) ; sym.std::__cxx11::basic_string_char__std::char_traits_char___std::allocator_char___::basic_string_char_const___std::allocator_char__const
│           0x00001227      48895de0       mov qword [var_20h], rbx
│           0x0000122b      488d45df       lea rax, [var_21h]
│           0x0000122f      4889c7         mov rdi, rax
│           0x00001232      e839feffff     call sym std::allocator<char>::~allocator() ; sym.std::allocator_char_::_allocator
│           0x00001237      488b5de0       mov rbx, qword [var_20h]
│           0x0000123b      4885db         test rbx, rbx
│       ┌─< 0x0000123e      7415           je 0x1255
│       │   0x00001240      4889df         mov rdi, rbx
│       │   0x00001243      e8e8fdffff     call sym std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string() ; sym.std::__cxx11::basic_string_char__std::char_traits_char___std::allocator_char___::_basic_string
│       │   0x00001248      be20000000     mov esi, 0x20               ; "@"
│       │   0x0000124d      4889df         mov rdi, rbx
│       │   0x00001250      e80bfeffff     call sym operator delete(void*, unsigned long) ; sym.operator_delete_void___unsigned_long
│       │   ; CODE XREF from main @ 0x123e
│       └─> 0x00001255      e86fffffff     call sym doOneThing()       ; sym.doOneThing
│           0x0000125a      e871ffffff     call sym doAnotherThing()   ; sym.doAnotherThing
│           0x0000125f      b800000000     mov eax, 0
│           0x00001264      488b4de8       mov rcx, qword [canary]
│           0x00001268      6448330c2528.  xor rcx, qword fs:[0x28]
│       ┌─< 0x00001271      7436           je 0x12a9
│      ┌──< 0x00001273      eb2f           jmp 0x12a4
..
│      ││   ; CODE XREF from main @ 0x1273
│      └──> 0x000012a4      e8d7fdffff     call sym.imp.__stack_chk_fail ; void __stack_chk_fail(void)
│       │   ; CODE XREF from main @ 0x1271
│       └─> 0x000012a9      4883c430       add rsp, 0x30
│           0x000012ad      5b             pop rbx
│           0x000012ae      415c           pop r12
│           0x000012b0      5d             pop rbp
└           0x000012b1      c3             ret
[0x000010d0]>
*/