gistfile1.txt

$ lldb ./result/bin/hello
(lldb) target create "./result/bin/hello"
Current executable set to './result/bin/hello' (x86_64).
(lldb) run
Process 27935 launched: '/src/nixpkgs/result/bin/hello' (x86_64)
warning: (x86_64) /src/nixpkgs/result/bin/hello(0x0000000100000000) address 0x0000000100000000 maps to more than one section: hello.__TEXT and hello.__TEXT
warning: (x86_64) /src/nixpkgs/result/bin/hello(0x0000000100000000) address 0x0000000100001000 maps to more than one section: hello.__DATA and hello.__DATA
Process 27935 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x42)
    frame #0: 0x0000000100000f64 hello`main + 4
hello`main:
->  0x100000f64 <+4>:  movl   $0x1, 0x42
    0x100000f6f <+15>: leaq   0x2c(%rip), %rdi          ; "Hello, %s\n"
    0x100000f76 <+22>: xorl   %eax, %eax
    0x100000f78 <+24>: callq  0x100000f82               ; symbol stub for: printf
Target 0: (hello) stopped.

gistfile2.txt

$ lldb ./result/bin/hello
(lldb) target create "./result/bin/hello"
Current executable set to './result/bin/hello' (x86_64).
(lldb) add-dsym ./result-debug/lib/debug/hello.dSYM
symbol file '/src/nixpkgs/result-debug/lib/debug/hello.dSYM/Contents/Resources/DWARF/hello' has been added to '/src/nixpkgs/result/bin/hello'
(lldb) run
Process 27955 launched: '/src/nixpkgs/result/bin/hello' (x86_64)
warning: (x86_64) /src/nixpkgs/result/bin/hello address 0x0000000100000000 maps to more than one section: hello.__TEXT and hello.__TEXT
warning: (x86_64) /src/nixpkgs/result/bin/hello address 0x0000000100001000 maps to more than one section: hello.__DATA and hello.__DATA
hello was compiled with optimization - stepping may behave oddly; variables may not be available.
Process 27955 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x42)
    frame #0: 0x0000000100000f64 hello`main [inlined] there_is_no_spoon at bmrwi0065zqf48kn4qjcfpafa3d1kxir-hello.c:5:10 [opt]
   2
   3    void there_is_no_spoon() {
   4        int* ptr = 0x42;
-> 5        *ptr = 1;
   6    }
   7
   8    int main(int argc, char* argv[]) {
Target 0: (hello) stopped.

hello.nix

with import <nixpkgs> {};

stdenv.mkDerivation {
  name = "hello-0.0.0";
  src = ./hello.c;
  outputs = [ "out" "debug" ];

  unpackPhase = ":";

  buildPhase = ''
    $CC -g -o hello $src
  '';

  installPhase = ''
    mkdir -p $out/bin $debug/lib/debug
    cp hello $out/bin
    cp -r hello.dSYM $debug/lib/debug
  '';
}