trace: Use -mcount-record for dynamic ftrace
authorAndi Kleen <ak@linux.intel.com>
Mon, 27 Nov 2017 21:34:13 +0000 (13:34 -0800)
committerSteven Rostedt (VMware) <rostedt@goodmis.org>
Mon, 28 May 2018 16:49:51 +0000 (12:49 -0400)
commit96f60dfa5819a065bfdd2f2ba0df7d9cbce7f4dd
tree98102816257e20f2be705a016b7049d16b159636
parent2824f5033248600673e3e126a4d135363cbfd9ac
trace: Use -mcount-record for dynamic ftrace

gcc 5 supports a new -mcount-record option to generate ftrace
tables directly. This avoids the need to run record_mcount
manually.

Use this option when available.

So far doesn't use -mcount-nop, which also exists now.

This is needed to make ftrace work with LTO because the
normal record-mcount script doesn't run over the link
time output.

It should also improve build times slightly in the general
case.
Link: http://lkml.kernel.org/r/20171127213423.27218-12-andi@firstfloor.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
scripts/Makefile.build