Fix use-after-free

[orgads]

Fixes #443

[orgads]

Actually this doesn't fix the crash.

[orgads]

Trace:

pass

Thread 1 "node" received signal SIGSEGV, Segmentation fault.
0x00007efc6846ec24 in ivm::Executor::GetCurrentEnvironment () at ../src/isolate/executor.h:168
168                     static thread_local Executor* current_executor;
(gdb) bt
#0  0x00007efc6846ec24 in ivm::Executor::GetCurrentEnvironment () at ../src/isolate/executor.h:168
#1  ivm::IsolateEnvironment::GetCurrent () at ../src/isolate/environment.h:201
#2  ivm::(anonymous namespace)::ExternalStringOneByte::~ExternalStringOneByte (this=0x7efc683d16c0, __in_chrg=<optimized out>)
    at ../src/external_copy/string.cc:49
#3  ivm::(anonymous namespace)::ExternalStringOneByte::~ExternalStringOneByte (this=0x7efc683d16c0, __in_chrg=<optimized out>)
    at ../src/external_copy/string.cc:52
#4  0x000055d785b8e912 in v8::internal::Heap::ExternalStringTable::TearDown() ()
#5  0x000055d785b8e944 in v8::internal::Heap::TearDownWithSharedHeap() ()
#6  0x000055d785b02553 in v8::internal::Isolate::Deinit() ()
#7  0x000055d785b04fb9 in v8::internal::Isolate::Delete(v8::internal::Isolate*) ()
#8  0x000055d78577af3c in node::NodeMainInstance::~NodeMainInstance() ()
#9  0x000055d7856df9be in node::Start(int, char**) ()
#10 0x00007efc6b2696d1 in libc_start_main_stage2 (main=0x55d78562ac80 <main>, argc=2, argv=0x7ffc898ef5a8) at src/env/__libc_start_main.c:95
#11 0x000055d7856326b1 in _start ()

[orgads]

It's use-after-free. I'll open an issue.

[laverdet]

The bugs are starting to pile up. I think it'll stay that way until I can find a month or so rethink some architecture given how nodejs and v8 have evolved over the past several years.

[orgads]

I didn't give up yet, I'm trying to fix it. I just prefer that it's tracked.

[orgads]

Fixed, please merge.

[laverdet]

Thanks for tracking down the issue. I took a closer look and went with a slightly different approach after understanding the issue further f6cc843