[U-Boot] [PATCH v4] Switch from archive libraries to partial linking

[Sebastien Carlier <sebastien.carlier@gmail.com>]

On 2010-11-15 11:54:07, Wolfgang Denk wrote:
> 
> I notice that the patch affects the size of the resulting U-Boot
> images.
> 
> For example:
> 
> Configuring for MiniFAP - Board: TQM5200, Options: MINIFAP
>    text    data     bss     dec     hex filename
>  358144   35208  303248  696600   aa118 ./u-boot	before
>  361340   35824  303332  700496   ab050 ./u-boot	after
> -------------------------------
> 		Delta:   +3896 Bytes
> 
> For other boards it's only a few hundred bytes, but why do we see
> such big increase here?

In this case, these libraries contribute 3260 bytes in unused
definitions:

- fs/fat/libfat.a: (1712 bytes)
	file.o:
	00000000 00000004 d current_filesystem
	00000004 00000200 D file_cwd
	00000000 00000018 d filesystems
	00000250 00000244 T file_cd
	000001d0 00000080 T file_detectfs
	00000000 00000048 T file_getfsname
	0000011c 000000b4 T file_ls
	00000048 000000d4 T file_read

- lib/libfdt/libfdt.a (1440 bytes)
	fdt_sw.o:
	00000000 0000006c T fdt_add_reservemap_entry
	0000028c 000000dc T fdt_begin_node
	00000504 0000009c T fdt_create
	000000b4 00000078 T fdt_end_node
	0000012c 00000160 T fdt_finish
	0000006c 00000048 T fdt_finish_reservemap
	00000368 0000019c T fdt_property

- drivers/pci/libpci.a: (108 bytes)
	pci_indirect.o:
	000001dc 0000006c T pci_setup_indirect

In each case, a whole object file contains exactly the unused
definitions, and could be excluded in the respective Makefile.

Re. my previous comment -- in other places objects get large when header
files define a lot of static inline functions, but these ('t' type)
definitions get squashed together during linking and do not add up.  If
however a large static inline function is defined but never used, it
will increase final binary size.

-- 
Sebastien