Pin and inline cme in JIT-ed method calls

```
$ benchmark-driver benchmark.yml -v --rbenv 'before --jit;after --jit' --repeat-count=12 --output=all
before --jit: ruby 2.8.0dev (2020-03-11T07:43:12Z master e89ebdcb87) +JIT [x86_64-linux]
after --jit: ruby 2.8.0dev (2020-03-11T07:54:18Z master 143776a0da) +JIT [x86_64-linux]
Calculating -------------------------------------
                                 before --jit           after --jit
Optcarrot Lan_Master.nes    73.86976729561439     77.20184819316513 fps
                            74.46997176460742     78.43493030231805
                            77.59686308754307     78.55714131655935
                            78.53693921126656     79.08984255596820
                            80.10158944910573     79.17751731838183
                            80.12254974411167     79.60853122429181
                            80.28678655204945     79.74674066871896
                            80.38690681095379     79.90624544440300
                            80.79223498756919     80.57881084206193
                            80.82857188422419     80.70677614429169
                            81.06447745878245     81.03868541295149
                            81.21620802278490     82.16354660940607
```

1 files changed, 2 insertions, 1 deletions

diff --git a/iseq.c b/iseq.c
index b6d463526d..d32a0929c6 100644
--- a/iseq.c
+++ b/iseq.c
@@ -364,8 +364,9 @@ rb_iseq_mark(const rb_iseq_t *iseq)
             for (unsigned int i=0; i<body->ci_size; i++) {
                 const struct rb_callcache *cc = cc_entries[i];
                 if (cc != NULL) {
-                    // Pin cc against GC.compact as the the address may be written in JIT-ed code.
+                    // Pin `cc` and `cc->cme` against GC.compact as their addresses may be written in JIT-ed code.
                     rb_gc_mark((VALUE)cc);
+                    rb_gc_mark((VALUE)vm_cc_cme(cc));
                 }
             }
         }