The hist__account_cycles() can account cycles per basic block. The basic
block information is saved in cycles_hist structure.

This patch processes each symbol, get basic blocks from cycles_hist and
add the basic block entries to a new hists (in 'struct block_hist').
Using a hists is because we need to compare, sort and print the basic
blocks later.

 v6:
 ---
 Since 'ops' argument is removed from hists__add_entry_block,
 update the code accordingly. No functional change.

 v5:
 ---
 Since now we still carry block_info in 'struct hist_entry'
 we don't need to use our own new/free ops for hist entries.
 And the block_info is released in hist_entry__delete.

 v3:
 ---
 1. In v2, we put block stuffs in 'struct hist_entry', but
 it's not a good design. In v3, we create a new
 'struct block_hist' and cast the 'struct hist_entry' to
 'struct block_hist' in some places, which can avoid adding
 new stuffs in 'struct hist_entry'.

 2. abs() -> labs(), in block_cycles_diff_cmp().

 v2:
 ---
 v1 adds the basic block entries to per data-file hists
 but v2 adds the basic block entries to per symbol hists.
 That is to keep current perf-diff format. Will show the
 result in next patches.
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1561713784-30533-5-git-send-email-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>