Possible double free of RenderableManager::Builder. Detected under wasm

[ncoder]

Describe the bug
Possible double-free situation in RenderableManager::Builder.
A bit early to tell, but the combination of using default copy constructors with a constructor/destructor that does a new/delete is usually a problem.

See RenderableManager.cpp

using BuilderType = RenderableManager;
BuilderType::Builder::Builder(size_t count) noexcept
        : BuilderBase<RenderableManager::BuilderDetails>(count) {
    mImpl->mEntries = new Entry[count];
}
BuilderType::Builder::~Builder() noexcept {
    delete [] mImpl->mEntries;
}
BuilderType::Builder::Builder(BuilderType::Builder&& rhs) noexcept = default;
BuilderType::Builder& BuilderType::Builder::operator=(BuilderType::Builder&& rhs) noexcept = default;

To Reproduce
Latest master (e9430dd)

Running triangle.html, if fails to run in debug.
With extra flags turned on, we get more data:

Adding these options to web/filament-js/CMakeLists.txt
set(LOPTS "${LOPTS} -s ASSERTIONS=1")
set(LOPTS "${LOPTS} -s SAFE_HEAP=1")
set(LOPTS "${LOPTS} -s DEMANGLE_SUPPORT=1")

Running out/cmake-webgl-debug/web/samples/triangle.html:

filament.js:1820 wasm streaming compile failed: abort("segmentation fault") at Error
at jsStackTrace (http://localhost:8080/filament.js:1146:13)
at stackTrace (http://localhost:8080/filament.js:1163:12)
at abort (http://localhost:8080/filament.js:13147:44)
at segfault (http://localhost:8080/filament.js:481:3)
at SAFE_HEAP_LOAD_i32_4_U_4 (wasm-function[8735]:29)
at __ZN8filament17RenderableManager7BuilderD2Ev [filament::RenderableManager::Builder::~Builder()] (wasm-function[3357]:47)
at _ZN10emscripten8internal7InvokerIN8filament17RenderableManager7BuilderEJiEE6invokeEPFS4_iEi [emscripten::internal::Invoker<filament::RenderableManager::Builder, int>::invoke(filament::RenderableManager::Builder (*)(int), int)] (wasm-function[1060]:80)
at dynCall_iii (wasm-function[8591]:16)
at dynCall_iii_396 (eval at makeDynCaller (http://localhost:8080/filament.js:6300:19), :4:12)
at Function.RenderableManager$Builder [as Builder] (eval at new (http://localhost:8080/filament.js:6496:27), :8:10)

Expected behavior
example should run.

Desktop (please complete the following information):
This is build and run on Mac + Chrome.
WebGL backend.

[romainguy]

@pixelflinger

[pixelflinger]

Yeah, that looks like a bug, when the && ctor is used. Good catch, thanks!

[prideout]

Thanks for looking at this Mathias.