[codegen] --gc:arc does not properly emit cstring, results in SIGSEGV #13321
Description
Code:
let a = "hello".cstring Default nim generates:
N_LIB_PRIVATE NIM_CONST NCSTRING a__xxx= "hello"; but with --gc:arc this results in:
static struct { NI cap; NIM_CHAR data[5+1]; } TM__xxx = { 5 | NIM_STRLIT_FLAG, "hello" }; N_LIB_PRIVATE NIM_CONST NCSTRING a__yyy = {5, (NimStrPayload*)&TM__xxx}; (mangling replaced by xxx and yyy for readability)
Using the cstring results in a SIGSEGV:
let a = "hello".cstring echo a nim c --gc:arc -r t2.nim ==168972== Memcheck, a memory error detector ==168972== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. ==168972== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info ==168972== Command: ./t2 ==168972== ==168972== Invalid read of size 1 ==168972== at 0x4839C62: strlen (vg_replace_strmem.c:461) ==168972== by 0x10A462: nimCStrLen (stdlib_system.nim.c:1089) ==168972== by 0x10D1A8: cstrToNimstr (stdlib_system.nim.c:2010) ==168972== by 0x112568: NimMainModule (@mt2.nim.c:153) ==168972== by 0x11243B: NimMainInner (@mt2.nim.c:119) ==168972== by 0x112468: NimMain (@mt2.nim.c:127) ==168972== by 0x1124A2: main (@mt2.nim.c:134) ==168972== Address 0x5 is not stack'd, malloc'd or (recently) free'd ==168972== Traceback (most recent call last)