From 9a76e77981bc96aab3f6fc36f654661d38b8c04e Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Fri, 24 Mar 2023 18:49:21 -0500
Subject: [PATCH] Update for undefined behavior sanitizer.

---
 src/core/parse.c    | 8 +++++---
 src/core/pp.c       | 2 +-
 src/core/specials.c | 5 +++--
 src/core/util.c     | 1 +
 4 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/core/parse.c b/src/core/parse.c
index 4d98490f..8358a996 100644
--- a/src/core/parse.c
+++ b/src/core/parse.c
@@ -1194,7 +1194,8 @@ static Janet parser_state_delimiters(const JanetParser *_p) {
             }
         }
     }
-    str = janet_string(p->buf + oldcount, (int32_t)(p->bufcount - oldcount));
+    /* avoid ptr arithmetic on NULL */
+    str = janet_string(oldcount ? p->buf + oldcount : p->buf, (int32_t)(p->bufcount - oldcount));
     p->bufcount = oldcount;
     return janet_wrap_string(str);
 }
@@ -1205,10 +1206,11 @@ static Janet parser_state_frames(const JanetParser *p) {
     states->count = count;
     uint8_t *buf = p->buf;
     /* Iterate arg stack backwards */
-    Janet *args = p->args + p->argcount;
+    Janet *args = p->argcount ? p->args + p->argcount : p->args; /* avoid ptr arithmetic on NULL */
     for (int32_t i = count - 1; i >= 0; --i) {
         JanetParseState *s = p->states + i;
-        if (s->flags & PFLAG_CONTAINER) {
+        /* avoid ptr arithmetic on args if NULL */
+        if ((s->flags & PFLAG_CONTAINER) && s->argn) {
             args -= s->argn;
         }
         states->data[i] = janet_wrap_parse_state(s, args, buf, (uint32_t) p->bufcount);
diff --git a/src/core/pp.c b/src/core/pp.c
index 1e424096..cd545ad1 100644
--- a/src/core/pp.c
+++ b/src/core/pp.c
@@ -637,7 +637,7 @@ static void janet_pretty_one(struct pretty *S, Janet x, int is_dict_value) {
                     }
                 }
 
-                janet_sorted_keys(kvs, cap, S->keysort_buffer + ks_start);
+                janet_sorted_keys(kvs, cap, S->keysort_buffer == NULL ? NULL : S->keysort_buffer + ks_start);
                 S->keysort_start += len;
                 if (!(S->flags & JANET_PRETTY_NOTRUNC) && (len > JANET_PRETTY_DICT_LIMIT)) {
                     len = JANET_PRETTY_DICT_LIMIT;
diff --git a/src/core/specials.c b/src/core/specials.c
index b8772218..a69d9627 100644
--- a/src/core/specials.c
+++ b/src/core/specials.c
@@ -203,8 +203,9 @@ static int destructure(JanetCompiler *c,
                     janetc_emit(c, JOP_JUMP);
                     int32_t label_loop_exit = janet_v_count(c->buffer);
 
-                    c->buffer[label_loop_cond_jump] |= (label_loop_exit - label_loop_cond_jump) << 16;
-                    c->buffer[label_loop_loop] |= (label_loop_start - label_loop_loop) << 8;
+                    /* avoid shifting negative numbers */
+                    c->buffer[label_loop_cond_jump] |= (uint32_t)(label_loop_exit - label_loop_cond_jump) << 16;
+                    c->buffer[label_loop_loop] |= (uint32_t)(label_loop_start - label_loop_loop) << 8;
 
                     janetc_freeslot(c, argi);
                     janetc_freeslot(c, arg);
diff --git a/src/core/util.c b/src/core/util.c
index 4fb4c4ca..4d24dca7 100644
--- a/src/core/util.c
+++ b/src/core/util.c
@@ -118,6 +118,7 @@ const char *const janet_status_names[16] = {
 #ifndef JANET_PRF
 
 int32_t janet_string_calchash(const uint8_t *str, int32_t len) {
+    if (NULL == str) return 5381;
     const uint8_t *end = str + len;
     uint32_t hash = 5381;
     while (str < end)