Squashed commit of the following:

commit 2d7d545c4c4bfce7fdcbcbe9baaeb437915742f0
Merge: 625a1249 b178914b
Author: Yukihiro "Matz" Matsumoto <[email protected]>
Date:   Fri Jun 5 14:35:13 2020 +0900

    Merge branch 'fix-mrb_open-with-nomem' of https://github.com/dearblue/mruby into dearblue-fix-mrb_open-with-nomem

commit b178914b111dda79a8f36ec4eb3e9d37b76f982e
Author: dearblue <[email protected]>
Date:   Sat Jan 19 22:22:44 2019 +0900

    Fix invalid pointer free inside other heap's block

     1. `e = mrb_obj_alloc(...)`
     2. `e->stack = mrb->c->stack` (`mrb->c->stack` is anywhere in the range `stbase...stend`)
     3. And raised exception by `mrb_malloc()`!
     4. `mrb_free(e->stack)` by GC part (wrong free)

commit 52e3d5d8585daf86af3ed12db5ab0efefbc9b956
Author: dearblue <[email protected]>
Date:   Sat Jan 19 21:55:36 2019 +0900

    Fix memory leak for temporary symbols when out of memory

commit 4c5499b88e47cc6012ad7d7379cb6bc74c6a0b60
Author: dearblue <[email protected]>
Date:   Sun Jan 20 11:42:07 2019 +0900

    Fix uninitialized pointer dereference for debug section

commit 8e993167dec62a9709d6faacd517729ddcedf4f9
Author: dearblue <[email protected]>
Date:   Sun Jan 20 11:41:09 2019 +0900

    Fix memory leak for temporary filenames when out of memory

commit 8b422577e6eae68a28121b88421d937e8707b487
Author: dearblue <[email protected]>
Date:   Sun Jan 20 10:57:51 2019 +0900

    Fix memory leak for irep when out of memory

commit 6b35ebf49a0aa3edb6bbda770ed58681e9c2e6af
Author: dearblue <[email protected]>
Date:   Sun Jan 20 10:55:50 2019 +0900

    Fix uninitialized pointer dereference when do not finished initializing irep

commit 2531f2631e67e0462749618e2344c733a29238f0
Author: dearblue <[email protected]>
Date:   Sun Jan 20 10:48:15 2019 +0900

    Fix NULL pointer dereference when do not finished initializing irep

commit e2d6896ebad13694800af49c2625e106b8440ddf
Author: dearblue <[email protected]>
Date:   Sat Jan 19 12:54:19 2019 +0900

    Fix memory leak for irep when out of memory by `mrb_proc_new()`

commit b6214ff8a0a1c73bc9554e39053878ac50bb683f
Author: dearblue <[email protected]>
Date:   Sat Jan 19 12:53:07 2019 +0900

    Fix memory leak for `khash_t` in `kh_init_size()` when out of memory by `kh_alloc()`

commit 19162dd6c11f0093d0011e7cab83b8f9e84c2c07
Author: dearblue <[email protected]>
Date:   Sun Jan 20 02:15:07 2019 +0900

    Fix memory leak for symbol string when out of memory in `kh_put()`

commit 15e67297ff54bc14ef359d6d1e745d760a4a255a
Author: dearblue <[email protected]>
Date:   Sun Jan 20 02:12:24 2019 +0900

    Fix keep wrong symbol index when out of memory

commit 3f8e2b375244f5441e8d62efa13c6e6a9afecb14
Author: dearblue <[email protected]>
Date:   Sun Jan 20 02:08:13 2019 +0900

    Fix keep wrong symbol capacity when out of memory

commit a3cfe755ab3e758046c3f4e30938ac8d567ed046
Author: dearblue <[email protected]>
Date:   Sat Jan 19 10:11:37 2019 +0900

    Fix NULL pointer dereference `mrb->c` by `mark_context()`

commit d9c7b6be6eb54630b64eea5c35be241e551676e5
Author: dearblue <[email protected]>
Date:   Sun Jan 20 15:25:09 2019 +0900

    Fix protect exception for print error message

commit 100642750e4d549f2e8050f8d6cabdf8825d4495
Author: dearblue <[email protected]>
Date:   Sun Jan 20 11:59:02 2019 +0900

    Protect exception for mruby core initialization

commit 7a0418304ec70764fa215bef3599f5f735222075
Author: dearblue <[email protected]>
Date:   Fri Jan 18 20:38:27 2019 +0900

    Fix memory leak for string object when out of memory

    The `mrb_str_pool()` function has a path to call `malloc()` twice.

    If occurs `NoMemoryError` exception in second `malloc()`,
    first `malloc()` pointer is not freed.

commit fef1c152ce4e52b9e4a34dc23aca5b02907ac639
Author: dearblue <[email protected]>
Date:   Sat Jan 19 13:05:09 2019 +0900

    Fix stack overflow when out of memory

    As a result of this change, no backtrace information is set
    for NoMemoryError (`mrb->nomem_err`).

    Detailes:

    When generating a backtrace, called `mrb_intern_lit()`,
    `mrb_str_new_cstr()` and `mrb_obj_iv_set()` function with
    `exc_debug_info()` function in `src/error.c`.

    If a `NoMemoryError` exception occurs at this time,
    the `exc_debug_info()` function will be called again,
    and in the same way `NoMemoryError` exception raised will result
    in an infinite loop to occurs stack overflow (and SIGSEGV).

commit da7d7f881bbbad9988a3a2b7bad8f2b72ff06bc6
Author: dearblue <[email protected]>
Date:   Sun Jan 20 12:00:38 2019 +0900

    Fix NULL pointer dereference `mrb->nomem_err` when not initialized

    Add internal functions (not `static`):

      * `mrb_raise_nomemory()`
      * `mrb_core_init_abort()`

1 files changed, 23 insertions, 5 deletions

diff --git a/include/mruby/khash.h b/include/mruby/khash.h
index c00357061..9f3f1a2cc 100644
--- a/include/mruby/khash.h
+++ b/include/mruby/khash.h
@@ -73,6 +73,7 @@ static const uint8_t __m_either[] = {0x03, 0x0c, 0x30, 0xc0};
   void kh_clear_##name(mrb_state *mrb, kh_##name##_t *h);               \
   khint_t kh_get_##name(mrb_state *mrb, kh_##name##_t *h, khkey_t key);           \
   khint_t kh_put_##name(mrb_state *mrb, kh_##name##_t *h, khkey_t key, int *ret); \
+  void kh_put_prepare_##name(mrb_state *mrb, kh_##name##_t *h);                   \
   void kh_resize_##name(mrb_state *mrb, kh_##name##_t *h, khint_t new_n_buckets); \
   void kh_del_##name(mrb_state *mrb, kh_##name##_t *h, khint_t x);                \
   kh_##name##_t *kh_copy_##name(mrb_state *mrb, kh_##name##_t *h);
@@ -95,16 +96,25 @@ kh_fill_flags(uint8_t *p, uint8_t c, size_t len)
    __hash_equal: hash comparation function
 */
 #define KHASH_DEFINE(name, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
-  void kh_alloc_##name(mrb_state *mrb, kh_##name##_t *h)                \
+  mrb_noreturn void mrb_raise_nomemory(mrb_state *mrb);                 \
+  int kh_alloc_simple_##name(mrb_state *mrb, kh_##name##_t *h)          \
   {                                                                     \
     khint_t sz = h->n_buckets;                                          \
     size_t len = sizeof(khkey_t) + (kh_is_map ? sizeof(khval_t) : 0);   \
-    uint8_t *p = (uint8_t*)mrb_malloc(mrb, sizeof(uint8_t)*sz/4+len*sz); \
+    uint8_t *p = (uint8_t*)mrb_malloc_simple(mrb, sizeof(uint8_t)*sz/4+len*sz); \
+    if (!p) { return 1; }                                               \
     h->size = h->n_occupied = 0;                                        \
     h->keys = (khkey_t *)p;                                             \
     h->vals = kh_is_map ? (khval_t *)(p+sizeof(khkey_t)*sz) : NULL;     \
     h->ed_flags = p+len*sz;                                             \
     kh_fill_flags(h->ed_flags, 0xaa, sz/4);                             \
+    return 0;                                                           \
+  }                                                                     \
+  void kh_alloc_##name(mrb_state *mrb, kh_##name##_t *h)                \
+  {                                                                     \
+    if (kh_alloc_simple_##name(mrb, h)) {                               \
+      mrb_raise_nomemory(mrb);                                          \
+    }                                                                   \
   }                                                                     \
   kh_##name##_t *kh_init_##name##_size(mrb_state *mrb, khint_t size) {  \
     kh_##name##_t *h = (kh_##name##_t*)mrb_calloc(mrb, 1, sizeof(kh_##name##_t)); \
@@ -112,7 +122,10 @@ kh_fill_flags(uint8_t *p, uint8_t c, size_t len)
       size = KHASH_MIN_SIZE;                                            \
     khash_power2(size);                                                 \
     h->n_buckets = size;                                                \
-    kh_alloc_##name(mrb, h);                                            \
+    if (kh_alloc_simple_##name(mrb, h)) {                               \
+      mrb_free(mrb, h);                                                 \
+      mrb_raise_nomemory(mrb);                                          \
+    }                                                                   \
     return h;                                                           \
   }                                                                     \
   kh_##name##_t *kh_init_##name(mrb_state *mrb) {                       \
@@ -171,12 +184,16 @@ kh_fill_flags(uint8_t *p, uint8_t c, size_t len)
       mrb_free(mrb, old_keys);                                          \
     }                                                                   \
   }                                                                     \
-  khint_t kh_put_##name(mrb_state *mrb, kh_##name##_t *h, khkey_t key, int *ret) \
+  void kh_put_prepare_##name(mrb_state *mrb, kh_##name##_t *h)          \
   {                                                                     \
-    khint_t k, del_k, step = 0;                                         \
     if (h->n_occupied >= khash_upper_bound(h)) {                        \
       kh_resize_##name(mrb, h, h->n_buckets*2);                         \
     }                                                                   \
+  }                                                                     \
+  khint_t kh_put_##name(mrb_state *mrb, kh_##name##_t *h, khkey_t key, int *ret) \
+  {                                                                     \
+    khint_t k, del_k, step = 0;                                         \
+    kh_put_prepare_##name(mrb, h);                                      \
     k = __hash_func(mrb,key) & khash_mask(h);                           \
     del_k = kh_end(h);                                                  \
     while (!__ac_isempty(h->ed_flags, k)) {                             \
@@ -239,6 +256,7 @@ kh_fill_flags(uint8_t *p, uint8_t c, size_t len)
 #define kh_destroy(name, mrb, h) kh_destroy_##name(mrb, h)
 #define kh_clear(name, mrb, h) kh_clear_##name(mrb, h)
 #define kh_resize(name, mrb, h, s) kh_resize_##name(mrb, h, s)
+#define kh_put_prepare(name, mrb, h) kh_put_prepare_##name(mrb, h)
 #define kh_put(name, mrb, h, k) kh_put_##name(mrb, h, k, NULL)
 #define kh_put2(name, mrb, h, k, r) kh_put_##name(mrb, h, k, r)
 #define kh_get(name, mrb, h, k) kh_get_##name(mrb, h, k)