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Compiler metaprogramming example

Here is an example of how one can use a compiler to generate large amounts of assembly code. It has been linked from metaprogramming because of the length of the example.

The following programme to count from 1 to 1000 is written in C++ :

/* hello.cpp */
  1. include

using std::cout; using std::endl;

main() {

       for(int i=1 ; i <= 1000 ; i++) {
               std::cout << i << std::endl;
       }
}

Using the GNU GCC C++ compiler g++ to generate intel x86 assembler as follows:

g++ hello.cpp -S

creates a new 221 line file hello.s as a result. The contents of this file is:

.file	"hello.cpp"
.local	_ZSt8__ioinit
.comm	_ZSt8__ioinit,1,1
.text
.align 2
.globl main
.type	main,@function
main:
.LFB1448:
pushl	%ebp
.LCFI0:
movl	%esp, %ebp
.LCFI1:
subl	$24, %esp
.LCFI2:
andl	$-16, %esp
movl	$0, %eax
subl	%eax, %esp
movl	$1, -4(%ebp)
.L2:
cmpl	$1000, -4(%ebp)
jle	.L5
jmp	.L3
.L5:
movl	-4(%ebp), %eax
movl	%eax, 4(%esp)
movl	$_ZSt4cout, (%esp)
call	_ZNSolsEi
movl	$_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_, 4(%esp)
movl	%eax, (%esp)
call	_ZNSolsEPFRSoS_E
leal	-4(%ebp), %eax
incl	(%eax)
jmp	.L2
.L3:
movl	$0, %eax
leave
ret
.LFE1448:
.Lfe1:
.size	main,.Lfe1-main
.align 2
.type	_Z41__static_initialization_and_destruction_0ii,@function
_Z41__static_initialization_and_destruction_0ii:
.LFB1460:
pushl	%ebp
.LCFI3:
movl	%esp, %ebp
.LCFI4:
subl	$24, %esp
.LCFI5:
cmpl	$65535, 12(%ebp)
jne	.L6
cmpl	$1, 8(%ebp)
jne	.L6
movl	$_ZSt8__ioinit, (%esp)
call	_ZNSt8ios_base4InitC1Ev
movl	$__dso_handle, 8(%esp)
movl	$0, 4(%esp)
movl	$__tcf_0, (%esp)
call	__cxa_atexit
.L6:
leave
ret
.LFE1460:
.Lfe2:
.size	_Z41__static_initialization_and_destruction_0ii,.Lfe2-_Z41__static_initialization_and_destruction_0ii
.align 2
.type	__tcf_0,@function
__tcf_0:
.LFB1461:
pushl	%ebp
.LCFI6:
movl	%esp, %ebp
.LCFI7:
subl	$8, %esp
.LCFI8:
movl	$_ZSt8__ioinit, (%esp)
call	_ZNSt8ios_base4InitD1Ev
leave
ret
.LFE1461:
.Lfe3:
.size	__tcf_0,.Lfe3-__tcf_0
.align 2
.type	_GLOBAL__I_main,@function
_GLOBAL__I_main:
.LFB1463:
pushl	%ebp
.LCFI9:
movl	%esp, %ebp
.LCFI10:
subl	$8, %esp
.LCFI11:
movl	$65535, 4(%esp)
movl	$1, (%esp)
call	_Z41__static_initialization_and_destruction_0ii
leave
ret
.LFE1463:
.Lfe4:
.size	_GLOBAL__I_main,.Lfe4-_GLOBAL__I_main
.section	.ctors,"aw",@progbits
.align 4
.long	_GLOBAL__I_main
.weak	pthread_mutex_unlock
.weak	pthread_mutex_trylock
.weak	pthread_mutex_lock
.weak	pthread_create
.weak	pthread_setspecific
.weak	pthread_getspecific
.weak	pthread_key_delete
.weak	pthread_key_create
.weak	pthread_once
.section	.eh_frame,"a",@progbits
.Lframe1:
.long	.LECIE1-.LSCIE1
.LSCIE1:
.long	0x0
.byte	0x1
.string	"zP"
.uleb128 0x1
.sleb128 -4
.byte	0x8
.uleb128 0x5
.byte	0x0
.long	__gxx_personality_v0
.byte	0xc
.uleb128 0x4
.uleb128 0x4
.byte	0x88
.uleb128 0x1
.align 4
.LECIE1:
.LSFDE1:
.long	.LEFDE1-.LASFDE1
.LASFDE1:
.long	.LASFDE1-.Lframe1
.long	.LFB1448
.long	.LFE1448-.LFB1448
.uleb128 0x0
.byte	0x4
.long	.LCFI0-.LFB1448
.byte	0xe
.uleb128 0x8
.byte	0x85
.uleb128 0x2
.byte	0x4
.long	.LCFI1-.LCFI0
.byte	0xd
.uleb128 0x5
.align 4
.LEFDE1:
.LSFDE3:
.long	.LEFDE3-.LASFDE3
.LASFDE3:
.long	.LASFDE3-.Lframe1
.long	.LFB1460
.long	.LFE1460-.LFB1460
.uleb128 0x0
.byte	0x4
.long	.LCFI3-.LFB1460
.byte	0xe
.uleb128 0x8
.byte	0x85
.uleb128 0x2
.byte	0x4
.long	.LCFI4-.LCFI3
.byte	0xd
.uleb128 0x5
.align 4
.LEFDE3:
.LSFDE5:
.long	.LEFDE5-.LASFDE5
.LASFDE5:
.long	.LASFDE5-.Lframe1
.long	.LFB1461
.long	.LFE1461-.LFB1461
.uleb128 0x0
.byte	0x4
.long	.LCFI6-.LFB1461
.byte	0xe
.uleb128 0x8
.byte	0x85
.uleb128 0x2
.byte	0x4
.long	.LCFI7-.LCFI6
.byte	0xd
.uleb128 0x5
.align 4
.LEFDE5:
.LSFDE7:
.long	.LEFDE7-.LASFDE7
.LASFDE7:
.long	.LASFDE7-.Lframe1
.long	.LFB1463
.long	.LFE1463-.LFB1463
.uleb128 0x0
.byte	0x4
.long	.LCFI9-.LFB1463
.byte	0xe
.uleb128 0x8
.byte	0x85
.uleb128 0x2
.byte	0x4
.long	.LCFI10-.LCFI9
.byte	0xd
.uleb128 0x5
.align 4
.LEFDE7:
.ident	"GCC: (GNU) 3.2.3 20030422 (Gentoo Linux 1.4 3.2.3-r2, propolice)"