ext/coverage/: add the oneshot mode

This patch introduces "oneshot_lines" mode for `Coverage.start`, which
checks "whether each line was executed at least once or not", instead of
"how many times each line was executed".  A hook for each line is fired
at most once, and after it is fired, the hook flag was removed; it runs
with zero overhead.

See [Feature #15022] in detail.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65195 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 1 deletions

diff --git a/compile.c b/compile.c
index 272b9ddacc..6e6825db3a 100644
--- a/compile.c
+++ b/compile.c
@@ -2013,7 +2013,9 @@ iseq_set_sequence(rb_iseq_t *iseq, LINK_ANCHOR *const anchor)
 		sp = calc_sp_depth(sp, iobj);
 		code_index += insn_data_length(iobj);
 		insn_num++;
-		if (ISEQ_COVERAGE(iseq) && ISEQ_LINE_COVERAGE(iseq) && (events & RUBY_EVENT_COVERAGE_LINE)) {
+                if (ISEQ_COVERAGE(iseq) && ISEQ_LINE_COVERAGE(iseq) &&
+                    (events & RUBY_EVENT_COVERAGE_LINE) &&
+                    !(rb_get_coverage_mode() & COVERAGE_TARGET_ONESHOT_LINES)) {
 		    int line = iobj->insn_info.line_no;
 		    RARRAY_ASET(ISEQ_LINE_COVERAGE(iseq), line - 1, INT2FIX(0));
 		}