-ffreestanding memcpy for copy-ctors

gistfile1.txt

$ cat copy_ctor.cpp 
struct Foo {
  char big[10240];
};

Foo fooCopy(const Foo * const in) {
  return Foo(*in);
}

$ ./clang++ -target arm-none-eabi copy_ctor.cpp -c
$ ./arm-none-eabi-objdump -d copy_ctor.o

copy_ctor.o:     file format elf32-littlearm


Disassembly of section .text:

00000000 <_Z7fooCopyPK3Foo>:
   0:	e92d4800 	push	{fp, lr}
   4:	e1a0b00d 	mov	fp, sp
   8:	e24dd010 	sub	sp, sp, #16
   c:	e1a02001 	mov	r2, r1
  10:	e1a03000 	mov	r3, r0
  14:	e50b1004 	str	r1, [fp, #-4]
  18:	e3a0cb0a 	mov	ip, #10240	; 0x2800
  1c:	e58d2008 	str	r2, [sp, #8]
  20:	e1a0200c 	mov	r2, ip
  24:	e58d3004 	str	r3, [sp, #4]
  28:	ebfffffe 	bl	0 <__aeabi_memcpy>
  2c:	e1a0d00b 	mov	sp, fp
  30:	e8bd4800 	pop	{fp, lr}
  34:	e12fff1e 	bx	lr
$ ./clang++ -target arm-none-eabi copy_ctor.cpp -c -ffreestanding
$ ./arm-none-eabi-objdump -d copy_ctor.o

copy_ctor.o:     file format elf32-littlearm


Disassembly of section .text:

00000000 <_Z7fooCopyPK3Foo>:
   0:	e92d4800 	push	{fp, lr}
   4:	e1a0b00d 	mov	fp, sp
   8:	e24dd010 	sub	sp, sp, #16
   c:	e1a02001 	mov	r2, r1
  10:	e1a03000 	mov	r3, r0
  14:	e50b1004 	str	r1, [fp, #-4]
  18:	e3a0cb0a 	mov	ip, #10240	; 0x2800
  1c:	e58d2008 	str	r2, [sp, #8]
  20:	e1a0200c 	mov	r2, ip
  24:	e58d3004 	str	r3, [sp, #4]
  28:	ebfffffe 	bl	0 <__aeabi_memcpy>
  2c:	e1a0d00b 	mov	sp, fp
  30:	e8bd4800 	pop	{fp, lr}
  34:	e12fff1e 	bx	lr