tail call with fake msgSend in Objective C

main.m

#import <Foundation/Foundation.h>
#import <objc/message.h>

extern id fake_msgSend(id, SEL, int) __attribute__((noinline));

@interface Foo : NSObject

- (id)foo:(int)n;

@end

@implementation Foo

-(id) foo:(int)n {
    if (n == 0) return @"";
    else return fake_msgSend(self, _cmd, n - 1); // tail-call optimization here
}

@end

id fake_msgSend(id f, SEL sel, int n) {
	return objc_msgSend(f, sel, n); // tail-call optimization here
}

int main(int argv, char ** argc) {
    id f = [Foo new];
    [f foo:5];
    return 0;
}

main.s

"-[Foo foo:]":                          ## @"\01-[Foo foo:]"
	.cfi_startproc
## BB#0:
	pushq	%rbp
Ltmp2:
	.cfi_def_cfa_offset 16
Ltmp3:
	.cfi_offset %rbp, -16
	movq	%rsp, %rbp
Ltmp4:
	.cfi_def_cfa_register %rbp
	testl	%edx, %edx
	jne	LBB0_2
## BB#1:
	leaq	L__unnamed_cfstring_(%rip), %rax
	popq	%rbp
	ret
LBB0_2:
	decl	%edx
	popq	%rbp
	jmp	_fake_msgSend           ## TAILCALL
	.cfi_endproc

	.globl	_fake_msgSend
	.align	4, 0x90
_fake_msgSend:                          ## @fake_msgSend
	.cfi_startproc
## BB#0:
	pushq	%rbp
Ltmp7:
	.cfi_def_cfa_offset 16
Ltmp8:
	.cfi_offset %rbp, -16
	movq	%rsp, %rbp
Ltmp9:
	.cfi_def_cfa_register %rbp
	xorb	%al, %al
	popq	%rbp
	jmp	_objc_msgSend           ## TAILCALL
	.cfi_endproc

	.globl	_main
	.align	4, 0x90
_main:                                  ## @main
	.cfi_startproc
## BB#0:
	pushq	%rbp
Ltmp12:
	.cfi_def_cfa_offset 16
Ltmp13:
	.cfi_offset %rbp, -16
	mov