gdb无法在Mac OS X中调试“ Hello World”

Question

I have the following smal C++ program

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    puts("!!!Hello World!!!");
    return EXIT_SUCCESS;
}

I compile in Mac OS X Leopard last release using:

g++ -g hello.cpp -o hello.exe

being g++:

host:bin macbook$ g++ --ver
Using built-in specs.
Target: i686-apple-darwin9
Configured with: /var/tmp/gcc/gcc-5493~1/src/configure --disable-checking -enable-werror --prefix=/usr --mandir=/share/man --enable-languages=c,objc,c++,obj-c++ --program-transform-name=/^[cg][^.-]*$/s/$/-4.0/ --with-gxx-include-dir=/include/c++/4.0.0 --with-slibdir=/usr/lib --build=i686-apple-darwin9 --with-arch=apple --with-tune=generic --host=i686-apple-darwin9 --target=i686-apple-darwin9
Thread model: posix
gcc version 4.0.1 (Apple Inc. build 5493)

then I try to debug this program using fsf-gdb 7.1:

fsf-gdb hello.exe

put a breakpoint in main:

(gdb) b main
Breakpoint 1 at 0x1f8f: file hello.cpp, line 5.

run the program:

(gdb) r
Starting program: /Users/horacio/work/software/gdb/gdb-7.2-inst/bin/hello.exe 

Breakpoint 1, main () at hello.cpp:5
5       puts("!!!Hello World!!!");

and try to step, and this happens:

(gdb) n
0x00003045 in ?? ()

This is the output if I do the same under Ubuntu Linux:

(gdb) n
!!!Hello World!!!
6       return EXIT_SUCCESS;

where gdb=7.1 and g++=4.3.4

What is the problem ???? I honestly do not understand why this does not work in mac os x.

Maybe the problem is the gdb version used in mac or the gcc version in mac. Which other alternatives exist for gdb in mac?

Thanks in advance

PS: Apple Leopard's gdb does not produce this error. But I want to use Eclipse CDT, and it can not work with Apple's gdb, that is why I am trying to use a non-Apple gdb version.

Answer 1

This works fine if you use the gdb bundled with Mac. Apple's gcc includes some small Apple-specific extensions, so would not be surprised that it is not 100% compatible with some other version of gdb. You may also have built your custom gdb incorrectly.

You mention that your g++ is 4.3.4, but the one you show above is 4.0.1.

Answer 2

Propably not releted to the actual issue but do remember that when you compile for debugging purposes, disable compiler optimizations with -O0 flag. If you don't pass that for gcc when compiling, you will get "funky" results when you are doing step execution with gdb.

Answer 3

My first thought was that your fsf-gdb doesn't understand Mach-0 binaries.

A quick look at Google came back with: http://reverse.put.as/2009/01/14/how-to-compile-gdb-and-other-apple-open-source-packages-in-mac-os-x/ which reveals that building gdb is not quite as trivial as one might think.