OSS-Fuzz: Add fuzzer targets compile process (#1767)

Signed-off-by: Arthur Chan <arthur.chan@adalogics.com>

test/fuzzers/fuzz_compile.c

@@ -0,0 +1,41 @@
+#include <stdint.h>
+#include <janet.h>
+
+/* Disable leak sanitizer */
+int __lsan_is_turned_off(void) {
+    return 1;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+
+    /* init Janet */
+    janet_init();
+
+    /* fuzz the compiler in src/core/compile.c: parse the untrusted source and
+       compile each produced form to bytecode */
+    JanetTable *env = janet_core_env(NULL);
+    JanetParser parser;
+    janet_parser_init(&parser);
+
+    JanetTryState tstate;
+    if (janet_try(&tstate) == JANET_SIGNAL_OK) {
+        for (size_t i = 0; i < size; i++) {
+            if (janet_parser_status(&parser) == JANET_PARSE_ERROR)
+                break;
+            janet_parser_consume(&parser, data[i]);
+            while (janet_parser_has_more(&parser)) {
+                Janet form = janet_parser_produce(&parser);
+                JanetCompileResult res = janet_compile(form, env, janet_cstring("fuzz"));
+                (void) res;
+            }
+        }
+    }
+    janet_restore(&tstate);
+
+    janet_parser_deinit(&parser);
+
+    /* cleanup Janet */
+    janet_deinit();
+
+    return 0;
+}