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, 23 insertions, 1 deletions

diff --git a/iseq.c b/iseq.c
index 343fc9e5b8..243afc2534 100644
--- a/iseq.c
+++ b/iseq.c
@@ -656,7 +656,8 @@ rb_iseq_new_top(const rb_ast_body_t *ast, VALUE name, VALUE path, VALUE realpath
     VALUE coverages = rb_get_coverages();
     if (RTEST(coverages)) {
         if (ast->line_count >= 0) {
-            VALUE coverage = rb_default_coverage(ast->line_count);
+            int len = (rb_get_coverage_mode() & COVERAGE_TARGET_ONESHOT_LINES) ? 0 : ast->line_count;
+            VALUE coverage = rb_default_coverage(len);
             rb_hash_aset(coverages, path, coverage);
         }
     }
@@ -1655,6 +1656,19 @@ rb_iseq_event_flags(const rb_iseq_t *iseq, size_t pos)
     }
 }
 
+void
+rb_iseq_clear_event_flags(const rb_iseq_t *iseq, size_t pos, rb_event_flag_t reset)
+{
+    struct iseq_insn_info_entry *entry = (struct iseq_insn_info_entry *)get_insn_info(iseq, pos);
+    if (entry) {
+	entry->events &= ~reset;
+        if (!(entry->events & iseq->aux.trace_events)) {
+            void rb_iseq_trace_flag_cleared(const rb_iseq_t *iseq, int pos);
+            rb_iseq_trace_flag_cleared(iseq, pos);
+        }
+    }
+}
+
 static VALUE
 local_var_name(const rb_iseq_t *diseq, VALUE level, VALUE op)
 {
@@ -2935,6 +2949,14 @@ encoded_iseq_trace_instrument(VALUE *iseq_encoded_insn, rb_event_flag_t turnon)
 }
 
 void
+rb_iseq_trace_flag_cleared(const rb_iseq_t *iseq, int pos)
+{
+    const struct rb_iseq_constant_body *const body = iseq->body;
+    VALUE *iseq_encoded = (VALUE *)body->iseq_encoded;
+    encoded_iseq_trace_instrument(&iseq_encoded[pos], 0);
+}
+
+void
 rb_iseq_trace_set(const rb_iseq_t *iseq, rb_event_flag_t turnon_events)
 {
     VM_ASSERT((turnon_events & ~ISEQ_TRACE_EVENTS) == 0);