From 9e3010f9162397c4f62f83fc5644d0f66d1ed751 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Filip=20Str=C3=B6mb=C3=A4ck?= <fstromback@gmail.com>
Date: Thu, 24 Apr 2025 21:28:49 +0200
Subject: [PATCH] Added test for GitHub issue #306

Note that it does not currently compile on recent GCC versions due to issue #302.
---
 test/function/238.c | 142 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 test/function/238.c

diff --git a/test/function/238.c b/test/function/238.c
new file mode 100644
index 0000000000..e034799786
--- /dev/null
+++ b/test/function/238.c
@@ -0,0 +1,142 @@
+/*
+TEST_HEADER
+ id = $Id$
+ summary = regression test for GitHub issue #306
+ language = c
+ link = testlib.o newfmt.o
+ parameters =
+END_HEADER
+*/
+
+#include "testlib.h"
+
+#if MPS_WORD_WIDTH > 32
+
+#include "mpsavm.h"
+#include "mpscamc.h"
+#include "newfmt.h"
+
+#include <stdio.h>
+
+/* On UNIX systems, the protection ProtSet in code/protix.c contained
+ * an assert that AddrOffset(base, limit) <= INT_MAX (also with the
+ * comment "should be redundant". An allocation larger than INT_MAX
+ * therefore triggers the assert, even though the MPS happily allows
+ * the allocation otherwise.
+ *
+ * Note that this is only a problem on platforms where sizeof(int) <
+ * sizeof(size_t). If sizeof(int) == sizeof(size_t) then everything
+ * works as expected.
+ *
+ * To trigger the assertion, it is usually enough to just ask the MPS
+ * to do a garbage collection cycle.
+ *
+ * As such, this test simply allocates a large block of memory and
+ * forces the MPS to do a collection. The test is enabled for other
+ * 64-bit platforms to detect other potential problems there as well.
+ */
+
+/* Number of allocations to do to encourage a collection. */
+#define NUM_ALLOCS 1000
+
+/* Number of times to allocate objects with a mps_arena_step in
+ * between. */
+#define NUM_STEPS 2
+
+/* Allocate an object that is >= 2 GiB. In a separate function to avoid
+ * accidentally pinning the pointer to the large object just in case. */
+static void create_large(mps_ap_t ap, mycell *store)
+{
+  mycell *created;
+  /* Allocate an object with a size that overflows a signed 32-bit integer. */
+  size_t target_bytes = 0x80000000;
+  /* This is not exact, which is why there is a slight margin. */
+  size_t elements = (target_bytes / sizeof(struct refitem)) + 1;
+  /* Make sure the number of elements fits in the int in newfmt. */
+  asserts(elements < INT_MAX, "INT_MAX is too small");
+
+  created = allocone(ap, (int)elements);
+
+  /* Add some pointers to make the MPS try to protect the object. */
+  setref(created, 0, created);
+  setref(created, 1, store);
+
+  /* Store it in 'store' so that it is kept alive. */
+  setref(store, 0, created);
+}
+
+
+static void test(void *stack_pointer)
+{
+  mps_arena_t arena;
+  mps_fmt_t format;
+  mps_pool_t pool;
+  mps_thr_t thread;
+  mps_root_t root;
+  mps_chain_t chain;
+  mps_ap_t ap;
+
+  mycell *object;
+
+  int i, j;
+
+  mps_gen_param_s gen_params[2] = {
+    { 512, 0.9 },
+    { 10 * 1024, 0.5 }
+  };
+
+  die(mps_arena_create_k(&arena, mps_arena_class_vm(), mps_args_none), "mps_arena_create_k");
+  die(mps_fmt_create_A(&format, arena, &fmtA), "create format");
+  die(mps_chain_create(&chain, arena, 2, gen_params), "mps_chain_create");
+  die(mps_thread_reg(&thread, arena), "mps_thread_reg");
+  die(mps_root_create_thread(&root, arena, thread, stack_pointer), "mps_root_create_thread");
+  MPS_ARGS_BEGIN(args) {
+     MPS_ARGS_ADD(args, MPS_KEY_FORMAT, format);
+     MPS_ARGS_ADD(args, MPS_KEY_CHAIN, chain);
+     die(mps_pool_create_k(&pool, arena, mps_class_amc(), args), "mps_pool_create_k");
+  } MPS_ARGS_END(args);
+
+  die(mps_ap_create_k(&ap, pool, mps_args_none), "mps_ap_create_k");
+
+  /* Allocate an object that we store the big object inside. To make
+   * it less likely that pinning it affects how the MPS behaves. */
+  object = allocone(ap, 1);
+  create_large(ap, object);
+
+  /* Allocate some other objects and ask for a small amount of
+   * collection work. This to encourage the MPS to raise a barrier on
+   * the large allocation. */
+  for (i = 0; i < NUM_STEPS; i++) {
+    for (j = 0; j < NUM_ALLOCS; j++)
+      allocone(ap, 100);
+
+    /* Ask the MPS to do a small amount of GC work. */
+    mps_arena_step(arena, 0.0001, 10000);
+  }
+
+  /* Tear down MPS data structures. */
+  mps_arena_park(arena);
+  mps_ap_destroy(ap);
+  mps_root_destroy(root);
+  mps_thread_dereg(thread);
+  mps_pool_destroy(pool);
+  mps_chain_destroy(chain);
+  mps_fmt_destroy(format);
+  mps_arena_destroy(arena);
+}
+
+#else
+
+static void test(void *stack_pointer)
+{
+  /* nothing to do on 32-bit systems */
+}
+
+#endif
+
+int main(void)
+{
+  run_test(test);
+  pass();
+  return 0;
+}