On Tue, May 24, 2016 at 09:20:27AM +0000, He Kuang wrote:
Use thread specific unwind ops to unwind cross-platform callchains.hi,
Currently, unwind methods is suitable for local unwind, this patch
changes the fixed methods to thread/map related. Each time a map is
inserted, we find the target arch and see if this platform can be
remote unwind. We test for x86 platform and only show proper
messages. The real unwind methods are not implemented, will be
introduced in next patch.
CONFIG_LIBUNWIND/NO_LIBUNWIND are changed to
CONFIG_LOCAL_LIBUNWIND/NO_LOCAL_LIBUNWIND for retaining local unwind
features. CONFIG_LIBUNWIND stands for either local or remote or both
unwind are supported and NO_LIBUNWIND means neither local nor remote
libunwind are supported.
I think this is too complex and error prone, I'd rather see it split
to several pieces. Basically every logicaly single piece should be
in separate patch for better readablebility and review.
I might be missing some but I'd mainly sepatate following:
- introducing struct unwind_libunwind_ops for local unwind
- moving unwind__prepare_access from thread_new into thread__insert_map
- keep unwind__prepare_access name instead of unwind__get_arch
and keep the return value, we need to bail out in case of error
- I wouldn't use null ops.. just check for for ops == NULL in wrapper function
- I understand we need to compile 3 objects from unwind-libunwind.c,
how about we create 3 files like:
which would setup all necessary defines and include unwind-libunwind.c like:
/* comments explaining every define ;-) */
#define LOCAL... REMOTE..
this way we will keep all the special setup for given unwind object
in one place and you can also use simple rule in the Build file like
without defining special rule:
libperf-$(CONFIG_LIBUNWIND_X86) += unwind-libunwind_x86_32.o
libperf-$(CONFIG_LIBUNWIND_AARCH64) += unwind-libunwind_arm64.o
the same way for the arch object:
Not sure I thought everything through, but I think this way
we'll keep it more maintainable and readable..
let me know what you think