From f0954e3fac03c35a91e544c2ffddc12b82d7f8a0 Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Thu, 10 Apr 2014 14:38:25 +0100
Subject: [PATCH] py: Add emergency exception object for when heap allocation
fails.
---
py/malloc.c | 14 ++++++++++++
py/misc.h | 1 +
py/objexcept.c | 59 +++++++++++++++++++++++++++++++++-----------------
3 files changed, 54 insertions(+), 20 deletions(-)
diff --git a/py/malloc.c b/py/malloc.c
index 45e939b6c..1d18a9a64 100644
--- a/py/malloc.c
+++ b/py/malloc.c
@@ -53,6 +53,20 @@ void *m_malloc(int num_bytes) {
return ptr;
}
+void *m_malloc_maybe(int num_bytes) {
+ void *ptr = malloc(num_bytes);
+ if (ptr == NULL) {
+ return NULL;
+ }
+#if MICROPY_MEM_STATS
+ total_bytes_allocated += num_bytes;
+ current_bytes_allocated += num_bytes;
+ UPDATE_PEAK();
+#endif
+ DEBUG_printf("malloc %d : %p\n", num_bytes, ptr);
+ return ptr;
+}
+
#if MICROPY_ENABLE_FINALISER
void *m_malloc_with_finaliser(int num_bytes) {
if (num_bytes == 0) {
diff --git a/py/misc.h b/py/misc.h
index 4112a6f0d..3f538b98e 100644
--- a/py/misc.h
+++ b/py/misc.h
@@ -38,6 +38,7 @@ typedef unsigned int uint;
#define m_del_var(obj_type, var_type, var_num, ptr) (m_free(ptr, sizeof(obj_type) + sizeof(var_type) * (var_num)))
void *m_malloc(int num_bytes);
+void *m_malloc_maybe(int num_bytes);
void *m_malloc_with_finaliser(int num_bytes);
void *m_malloc0(int num_bytes);
void *m_realloc(void *ptr, int old_num_bytes, int new_num_bytes);
diff --git a/py/objexcept.c b/py/objexcept.c
index 51e7a2615..1ef3e31dc 100644
--- a/py/objexcept.c
+++ b/py/objexcept.c
@@ -20,6 +20,9 @@ typedef struct _mp_obj_exception_t {
// Instance of MemoryError exception - needed by mp_malloc_fail
const mp_obj_exception_t mp_const_MemoryError_obj = {{&mp_type_MemoryError}, MP_OBJ_NULL, {{&mp_type_tuple}, 0}};
+// Local non-heap memory for allocating an exception when we run out of RAM
+STATIC mp_obj_exception_t mp_emergency_exception_obj;
+
// Instance of GeneratorExit exception - needed by generator.close()
// This would belong to objgenerator.c, but to keep mp_obj_exception_t
// definition module-private so far, have it here.
@@ -51,7 +54,13 @@ STATIC mp_obj_t mp_obj_exception_make_new(mp_obj_t type_in, uint n_args, uint n_
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError, "%s does not take keyword arguments", mp_obj_get_type_str(type_in)));
}
- mp_obj_exception_t *o = m_new_obj_var(mp_obj_exception_t, mp_obj_t, n_args);
+ mp_obj_exception_t *o = m_malloc_maybe(sizeof(mp_obj_exception_t) + n_args * sizeof(mp_obj_t));
+ if (o == NULL) {
+ // Couldn't allocate heap memory; use local data instead.
+ o = &mp_emergency_exception_obj;
+ // We can't store any args.
+ n_args = 0;
+ }
o->base.type = type;
o->traceback = MP_OBJ_NULL;
o->args.base.type = &mp_type_tuple;
@@ -196,25 +205,35 @@ mp_obj_t mp_obj_new_exception_msg_varg(const mp_obj_type_t *exc_type, const char
assert(exc_type->make_new == mp_obj_exception_make_new);
// make exception object
- mp_obj_exception_t *o = m_new_obj_var(mp_obj_exception_t, mp_obj_t, 1);
- o->base.type = exc_type;
- o->traceback = MP_OBJ_NULL;
- o->args.base.type = &mp_type_tuple;
- o->args.len = 1;
-
- if (fmt == NULL) {
- // no message
- assert(0);
+ mp_obj_exception_t *o = m_malloc_maybe(sizeof(mp_obj_exception_t) + 1 * sizeof(mp_obj_t));
+ if (o == NULL) {
+ // Couldn't allocate heap memory; use local data instead.
+ // Unfortunately, we won't be able to format the string...
+ o = &mp_emergency_exception_obj;
+ o->base.type = exc_type;
+ o->traceback = MP_OBJ_NULL;
+ o->args.base.type = &mp_type_tuple;
+ o->args.len = 0;
} else {
- // render exception message and store as .args[0]
- // TODO: optimize bufferbloat
- vstr_t *vstr = vstr_new();
- va_list ap;
- va_start(ap, fmt);
- vstr_vprintf(vstr, fmt, ap);
- va_end(ap);
- o->args.items[0] = mp_obj_new_str((byte*)vstr->buf, vstr->len, false);
- vstr_free(vstr);
+ o->base.type = exc_type;
+ o->traceback = MP_OBJ_NULL;
+ o->args.base.type = &mp_type_tuple;
+ o->args.len = 1;
+
+ if (fmt == NULL) {
+ // no message
+ assert(0);
+ } else {
+ // render exception message and store as .args[0]
+ // TODO: optimize bufferbloat
+ vstr_t *vstr = vstr_new();
+ va_list ap;
+ va_start(ap, fmt);
+ vstr_vprintf(vstr, fmt, ap);
+ va_end(ap);
+ o->args.items[0] = mp_obj_new_str((byte*)vstr->buf, vstr->len, false);
+ vstr_free(vstr);
+ }
}
return o;
@@ -259,7 +278,7 @@ void mp_obj_exception_clear_traceback(mp_obj_t self_in) {
void mp_obj_exception_add_traceback(mp_obj_t self_in, qstr file, machine_uint_t line, qstr block) {
// make sure self_in is an exception instance
// TODO add traceback information to user-defined exceptions (need proper builtin subclassing for that)
- if (mp_obj_get_type(self_in)->make_new == mp_obj_exception_make_new) {
+ if (mp_obj_get_type(self_in)->make_new == mp_obj_exception_make_new && self_in != &mp_emergency_exception_obj) {
mp_obj_exception_t *self = self_in;
// for traceback, we are just using the list object for convenience, it's not really a list of Python objects
--
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