From 955ea13ee59cf0960012e38d53409a9319cd920a Mon Sep 17 00:00:00 2001
From: Gareth Rees <gdr@ravenbrook.com>
Date: Mon, 18 Jun 2018 15:41:29 +0100
Subject: [PATCH] Lo asserts on fixes to unallocated objects.

New MMQA test case conerr/62.c checks this.

Copied from Perforce
 Change: 193909
---
 mps/code/poollo.c          |  7 ++++
 mps/test/conerr/60.c       |  2 +-
 mps/test/conerr/61.c       |  2 +-
 mps/test/conerr/62.c       | 75 ++++++++++++++++++++++++++++++++++++++
 mps/test/testsets/conerr   |  2 +
 mps/test/testsets/coolonly |  2 +
 6 files changed, 88 insertions(+), 2 deletions(-)
 create mode 100644 mps/test/conerr/62.c

diff --git a/mps/code/poollo.c b/mps/code/poollo.c
index 4a1ebea034a..8e17b7c0948 100644
--- a/mps/code/poollo.c
+++ b/mps/code/poollo.c
@@ -724,6 +724,13 @@ static Res LOFix(Pool pool, ScanState ss, Seg seg, Ref *refIO)
   }
 
   i = AddrOffset(SegBase(seg), base) >> lo->alignShift;
+
+  /* Not a real reference if unallocated. */
+  if (!BTGet(loseg->alloc, i)) {
+    AVER_CRITICAL(ss->rank == RankAMBIG);
+    return ResOK;
+  }
+
   if(!BTGet(loseg->mark, i)) {
     ss->wasMarked = FALSE;  /* <design/fix/#protocol.was-marked> */
     if(ss->rank == RankWEAK) {
diff --git a/mps/test/conerr/60.c b/mps/test/conerr/60.c
index d8b62bcd249..de43e0953f6 100644
--- a/mps/test/conerr/60.c
+++ b/mps/test/conerr/60.c
@@ -45,9 +45,9 @@ static void test(void)
 
  /* p is in the LO pool */
  p = allocone(ap_lo, 0, NULL, NULL, sizeof(mycell));
- unaligned = (void *)((char*)p + 1);
 
  /* q is in the AMS pool with unaligned exact reference to p */
+ unaligned = (void *)((char*)p + 1);
  q = allocone(ap_ams, 1, p, unaligned, sizeof(mycell));
 
  mps_arena_start_collect(arena);
diff --git a/mps/test/conerr/61.c b/mps/test/conerr/61.c
index 557375a8637..f17ee06f778 100644
--- a/mps/test/conerr/61.c
+++ b/mps/test/conerr/61.c
@@ -39,9 +39,9 @@ static void test(void)
 
  /* p is in the AWL pool */
  p = allocone(ap, 0, NULL, NULL, sizeof(mycell));
- unaligned = (void *)((char*)p + 1);
 
  /* q is in the AWL pool with unaligned exact reference to p */
+ unaligned = (void *)((char*)p + 1);
  q = allocone(ap, 1, p, unaligned, sizeof(mycell));
 
  mps_arena_start_collect(arena);
diff --git a/mps/test/conerr/62.c b/mps/test/conerr/62.c
new file mode 100644
index 00000000000..55e86998ad6
--- /dev/null
+++ b/mps/test/conerr/62.c
@@ -0,0 +1,75 @@
+/* 
+TEST_HEADER
+ id = $Id$
+ summary = LO pool asserts on exact reference to unallocated object
+ language = c
+ link = myfmt.o testlib.o
+OUTPUT_SPEC
+ assert = true
+ assertfile P= poollo.c
+ assertcond = ss->rank == RankAMBIG
+END_HEADER
+*/
+
+#include "testlib.h"
+#include "mpscams.h"
+#include "mpsclo.h"
+#include "myfmt.h"
+
+static void test(void)
+{
+ void *marker = &marker;
+ mps_arena_t arena;
+ mps_pool_t pool_ams, pool_lo;
+ mps_thr_t thread;
+ mps_root_t root;
+ mps_fmt_t format;
+ mps_ap_t ap_ams, ap_lo;
+ mps_addr_t p, q, unallocated;
+
+ cdie(mps_arena_create_k(&arena, mps_arena_class_vm(), mps_args_none), "create arena");
+ mps_arena_park(arena);
+ cdie(mps_thread_reg(&thread, arena), "register thread");
+ cdie(mps_root_create_thread(&root, arena, thread, marker), "create root");
+ cdie(mps_fmt_create_A(&format, arena, &fmtA), "create format");
+ MPS_ARGS_BEGIN(args) {
+   MPS_ARGS_ADD(args, MPS_KEY_FORMAT, format);
+   cdie(mps_pool_create_k(&pool_ams, arena, mps_class_ams(), args), "ams pool");
+ } MPS_ARGS_END(args);
+ MPS_ARGS_BEGIN(args) {
+   MPS_ARGS_ADD(args, MPS_KEY_FORMAT, format);
+   cdie(mps_pool_create_k(&pool_lo, arena, mps_class_lo(), args), "lo pool");
+ } MPS_ARGS_END(args);
+ cdie(mps_ap_create(&ap_ams, pool_ams, mps_rank_exact()), "ams ap");
+ cdie(mps_ap_create_k(&ap_lo, pool_lo, mps_args_none), "lo ap");
+
+ /* p is in the LO pool */
+ p = allocone(ap_lo, 0, NULL, NULL, sizeof(mycell));
+
+ /* Destroy the LO allocation point so that p's segment gets unbuffered. */
+ mps_ap_destroy(ap_lo);
+
+ /* q is in the AMS pool with exact reference to p and unallocated object */
+ unallocated = (void *)((char*)p + sizeof(mycell));
+ q = allocone(ap_ams, 1, p, unallocated, sizeof(mycell));
+
+ mps_arena_start_collect(arena);
+ mps_arena_park(arena);
+
+ /* Keep q (and thus p) alive during the collection. */
+ report("q", "%p", q);
+
+ mps_ap_destroy(ap_ams);
+ mps_pool_destroy(pool_lo);
+ mps_pool_destroy(pool_ams);
+ mps_fmt_destroy(format);
+ mps_root_destroy(root);
+ mps_thread_dereg(thread);
+ mps_arena_destroy(arena);
+}
+
+int main(void)
+{
+ easy_tramp(test);
+ return 0;
+}
diff --git a/mps/test/testsets/conerr b/mps/test/testsets/conerr
index 98d2e53520c..5d3a0af8171 100644
--- a/mps/test/testsets/conerr
+++ b/mps/test/testsets/conerr
@@ -68,3 +68,5 @@ conerr/56.c
 % conerr/58.c -- see <code/ld.c#.stale.no-arena-check>
 conerr/59.c
 % conerr/60.c -- assertion is on the critical path
+% conerr/61.c -- assertion is on the critical path
+% conerr/62.c -- assertion is on the critical path
diff --git a/mps/test/testsets/coolonly b/mps/test/testsets/coolonly
index 636ec8ee288..10fe30a6310 100644
--- a/mps/test/testsets/coolonly
+++ b/mps/test/testsets/coolonly
@@ -46,4 +46,6 @@ conerr/22.c
 conerr/23.c
 conerr/27.c
 conerr/60.c
+conerr/61.c
+conerr/62.c
 function/72.c