From 33af0429ea875cd11d4ffbeff1c278d4cc10bb0e Mon Sep 17 00:00:00 2001
From: mame <mame@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 22 Aug 2018 05:24:50 +0000
Subject: thread.c (rb_reset_coverages): remove coverage counters from all
 ISeqs

When coverage measurement is enabled, the compiler makes each iseq have
a reference to the counter array of coverage.
Even after coverage measurement is disabled, the reference is kept.
And, if coverage measurement is restarted, a coverage hook will increase
the counter.  This is completely meaningless; it brings just overhead.

To remove this meaninglessness, this change removes all the reference
when coverage measuement is stopped.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64504 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 iseq.c   | 19 +++++++++++++++++++
 iseq.h   |  2 ++
 thread.c |  1 +
 3 files changed, 22 insertions(+)

diff --git a/iseq.c b/iseq.c
index bb53518168..68ca781d4c 100644
--- a/iseq.c
+++ b/iseq.c
@@ -966,6 +966,25 @@ rb_iseq_coverage(const rb_iseq_t *iseq)
     return ISEQ_COVERAGE(iseq);
 }
 
+static int
+remove_coverage_i(void *vstart, void *vend, size_t stride, void *data)
+{
+    VALUE v = (VALUE)vstart;
+    for (; v != (VALUE)vend; v += stride) {
+	if (rb_obj_is_iseq(v)) {
+            rb_iseq_t *iseq = (rb_iseq_t *)v;
+            ISEQ_COVERAGE_SET(iseq, Qnil);
+	}
+    }
+    return 0;
+}
+
+void
+rb_iseq_remove_coverage_all()
+{
+    rb_objspace_each_objects(remove_coverage_i, NULL);
+}
+
 /* define wrapper class methods (RubyVM::InstructionSequence) */
 
 static void
diff --git a/iseq.h b/iseq.h
index b8c10d8816..44ed3bdedf 100644
--- a/iseq.h
+++ b/iseq.h
@@ -178,6 +178,8 @@ VALUE rb_iseq_first_lineno(const rb_iseq_t *iseq);
 VALUE rb_iseq_method_name(const rb_iseq_t *iseq);
 void rb_iseq_code_location(const rb_iseq_t *iseq, int *first_lineno, int *first_column, int *last_lineno, int *last_column);
 
+void rb_iseq_remove_coverage_all();
+
 /* proc.c */
 const rb_iseq_t *rb_method_iseq(VALUE body);
 const rb_iseq_t *rb_proc_get_iseq(VALUE proc, int *is_proc);
diff --git a/thread.c b/thread.c
index 74a556ba38..b093a9a2e4 100644
--- a/thread.c
+++ b/thread.c
@@ -5404,6 +5404,7 @@ rb_reset_coverages(void)
 {
     VALUE coverages = rb_get_coverages();
     st_foreach(rb_hash_tbl_raw(coverages), reset_coverage_i, 0);
+    rb_iseq_remove_coverage_all();
     GET_VM()->coverages = Qfalse;
     rb_remove_event_hook((rb_event_hook_func_t) update_line_coverage);
     if (GET_VM()->coverage_mode & COVERAGE_TARGET_BRANCHES) {
-- 
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