gdb 8.2 can't recognized executable file on macOS Mojave 10.14

Question

I get gdb by brew install gdb.

The source file content is:

#include 
int main(){
    int a = 10;
    for(int i = 0; i<          


        

Answer 1

The problem is that clang-1000.11.45.2 distributed with Apple LLVM version 10.0.0 add a new load command to o-mach executables named LC_BUILD_VERSION.

$ otool -l test.o
...
Load command 1
       cmd LC_BUILD_VERSION
   cmdsize 24
  platform macos
       sdk n/a
     minos 10.14
    ntools 0
...

From the apple source:

/*
 * The build_version_command contains the min OS version on which this
 * binary was built to run for its platform.  The list of known platforms and
 * tool values following it.
 */

So currently bfd (program used by gdb to manipulate executables) is not able to interpret this command, and returns the error.

The temporary solution I found is directly edit bfd sources provide with gdb. I've only test with gdb-8.0.1.

First, download gdb-8.0.1 sources from mirrors. Then add to gdb-8.0.1/bfd/mach-o.c the following code at line 4649 :

case BFD_MACH_O_LC_BUILD_VERSION:
break;

And finally add int gdb-8.0.1/include/mach-o/loader.h :

  BFD_MACH_O_LC_BUILD_VERSION = 0x32

at line 189 (don't forget to add a , at the end of the line 188 after BFD_MACH_O_LC_VERSION_MIN_WATCHOS = 0x30).

After these instructions you can follow a classic gdb compilation as indicate inside the README :

run the ``configure'' script here, e.g.:

    ./configure 
    make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
    make install

Don't forget to sign gdb as explain here. If you still get the (os/kern) failure (0x5) error, just run sudo gdb.

This is a temporary solution waiting for the GNU team fix the problem directly on the repo.

EDIT

Binutils-gdb has been updated, these changes are now implemented in commit fc7b364.

Hope It will be helpfull.