From 4aaa844b8b749d9fe55727dc47224d972c60ea40 Mon Sep 17 00:00:00 2001
From: Luke Gorrie <luke@snabb.co>
Date: Fri, 28 Jul 2017 10:01:18 +0000
Subject: [PATCH 1/2] lj_jit.h: Save 'parent' and 'exitno' fields in GCtrace

For debugging purposes it is very useful to be able to refer to the
origin of a trace (parent/exit) and so this change stores that
information persistently in GCtrace instead of only ephemerally in
jit_State.

These fields are now duplicated in jit_State (valid while recording)
and GCtrace (valid after recording.) This duplication could be avoided
by putting them only in GCtrace and accessing them via J->cur but this
would be a more noisy change since the existing fields are accessed
from many places including DynASM macros.
---
 src/lj_jit.h   | 2 ++
 src/lj_trace.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/src/lj_jit.h b/src/lj_jit.h
index b3408e9bb2..8a522973bb 100644
--- a/src/lj_jit.h
+++ b/src/lj_jit.h
@@ -199,6 +199,8 @@ typedef struct GCtrace {
   TraceNo1 root;	/* Root trace of side trace (or 0 for root traces). */
   TraceNo1 nextroot;	/* Next root trace for same prototype. */
   TraceNo1 nextside;	/* Next side trace of same root trace. */
+  TraceNo1 parent;      /* Parent of this trace (or 0 for root traces). */
+  ExitNo exitno;        /* Exit number in parent (valid for side-traces only). */
   uint8_t sinktags;	/* Trace has SINK tags. */
   uint8_t unused1;
 } GCtrace;
diff --git a/src/lj_trace.c b/src/lj_trace.c
index 0b674ec276..99c49fa0a9 100644
--- a/src/lj_trace.c
+++ b/src/lj_trace.c
@@ -109,6 +109,8 @@ static void trace_save(jit_State *J, GCtrace *T)
   size_t szins = (J->cur.nins-J->cur.nk)*sizeof(IRIns);
   char *p = (char *)T + sztr;
   memcpy(T, &J->cur, sizeof(GCtrace));
+  T->parent = J->parent;
+  T->exitno = J->exitno;
   setgcrefr(T->nextgc, J2G(J)->gc.root);
   setgcrefp(J2G(J)->gc.root, T);
   newwhite(J2G(J), T);

From fcf7053ddd8da467b90038f499cc8eb21e75c672 Mon Sep 17 00:00:00 2001
From: Luke Gorrie <luke@snabb.co>
Date: Fri, 28 Jul 2017 10:23:51 +0000
Subject: [PATCH 2/2] check-generated-code.nix: Add more verbosity

Just to be clear about what is actually being checked.
---
 check-generated-code.nix | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/check-generated-code.nix b/check-generated-code.nix
index 46efe67f84..78ff51b2f8 100644
--- a/check-generated-code.nix
+++ b/check-generated-code.nix
@@ -11,8 +11,10 @@ overrideDerivation raptorjit (as:
   {
     checkPhase = ''
       for f in ${generatedFiles}; do
+        echo "checking $f.."
         diff -u src/reusevm/$f src/$f
       done
+      echo "all files ok"
     '';
     doCheck = true;
   })