[dpdk-dev] [PATCH v2 01/10] build: add an option to enable LTO build

[Andrzej Ostruszka]

On 9/23/19 6:13 PM, Bruce Richardson wrote:
[...]
> However, testing on my system with the meson build, I'm getting lots of
> link errors [See below]. Any suggestions?
> 
> /Bruce
> 
> /usr/bin/ld: /tmp/dpdk-testpmd.hncbtE.ltrans93.ltrans.o: in function `ena_stop':
> <artificial>:(.text+0x9ed6): undefined reference to `rte_timer_stop'
[...]

What is 'default_library'?  It should be 'shared' as mentioned in the
docs.  The problem is that RTE_BUILD_SHARED_LIB is statically defined in
rte_config.h used by meson build.  This results in broken static
libraries (those that are using versioned symbols - like
timer/lpm/distributor) - since the MAP_STATIC_SYMBOL macro defining the
default alias is empty.  With LTO compiler (or rather linker) is quite
aggressive in removing stuff that it thinks is not needed.

Regards
Andrzej

PS. IMHO this SHARED_LIB define should be removed from the rte_config.h
and meson.build should be updated to detect 'default_library' and add it
as needed.  Don't know exactly how meson behaves if 'default_library' is
'both' - the docs say that it reuses objects from static build, so we
might have to work around it for LTO & 'both'.