compile.c (iseq_compile_each0): remove irrelevant tracecoverage

This change removes tracecoverage instructions on a line that has any
NODE but is non-significant, such as, just one literal.

This fixes the following failure that occurs only when coverage is
enabled:

  1) Failure:
TestISeq#test_to_a_lines [.../ruby/test/ruby/test_iseq.rb:56]:
<[3, 4, 7, 9]> expected but was
<[3, 4, 5, 6, 7, 8, 9]>.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61711 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 12 insertions, 0 deletions

diff --git a/compile.c b/compile.c
index 3d94cf1bad..6d9d0f4180 100644
--- a/compile.c
+++ b/compile.c
@@ -7169,6 +7169,18 @@ iseq_compile_each0(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *node, in
 	return COMPILE_NG;
     }
 
+    /* remove tracecoverage instruction if there is no relevant instruction */
+    if (IS_TRACE(ret->last) && ((TRACE*) ret->last)->event == RUBY_EVENT_LINE) {
+	LINK_ELEMENT *insn = ret->last->prev;
+	if (IS_INSN(insn) &&
+	    IS_INSN_ID(insn, tracecoverage) &&
+	    FIX2LONG(OPERAND_AT(insn, 0)) == RUBY_EVENT_COVERAGE_LINE
+	) {
+	    ELEM_REMOVE(insn); /* remove tracecovearge */
+	    RARRAY_ASET(ISEQ_LINE_COVERAGE(iseq), line - 1, Qnil);
+	}
+    }
+
     debug_node_end();
     return COMPILE_OK;
 }