YJIT: Fix unexpected truncation when outputing VALUE

Previously, YJIT incorrectly discarded the upper 32 bits of the object
pointer when writing out VALUEs to setup default keyword arguments.

In addition to incorrectly truncating, the output pointers were not
properly tracked for handling GC compaction moving the referenced
objects.

YJIT previously attempted to encode a mov instruction with a memory
destination and a 64 bit immediate when there is no such encoding
possible in the ISA. Add an assert to mitigate not being able to
catch this at build time.

1 files changed, 15 insertions, 0 deletions

diff --git a/bootstraptest/test_yjit.rb b/bootstraptest/test_yjit.rb
index 2ac37df0a2..0b2b78ca4a 100644
--- a/bootstraptest/test_yjit.rb
+++ b/bootstraptest/test_yjit.rb
@@ -1,3 +1,18 @@
+assert_equal '18374962167983112447', %q{
+  # regression test for incorrectly discarding 32 bits of a pointer when it
+  # comes to default values.
+  def large_literal_default(n: 0xff00_fabcafe0_00ff)
+    n
+  end
+
+  def call_graph_root
+    large_literal_default
+  end
+
+  call_graph_root
+  call_graph_root
+}
+
 assert_normal_exit %q{
   # regression test for a leak caught by an asert on --yjit-call-threshold=2
   Foo = 1