No, modulo the aligned allocation overloads, but applications are allowed to override the default standard library operator new with their own, even on platforms that don't have an equivalent to ELF symbol interposition.
That doesn't really explain where the dependency on the C++ runtime come from tho, as far as I know the dependency chain is std::allocator -> operator new -> malloc, but from the post the replacement only strips out the `operator new`.
Notably I thought the issue would be the throwing of `std::bad_alloc`, but the new version still implements std::allocator, and throws bad_alloc.
And so I assume the issue is that the global `operator new` is concrete (it just takes the size of the allocation), thus you need to link to the C++ runtime just to get that function? In which case you might be able to get the same gains by redefining the global `operator new` and `operator delete`, without touching the allocator.
Alternatively, you might be able to statically link the C++ runtime and have DCE take care of the rest.
> Notably I thought the issue would be the throwing of `std::bad_alloc`, but the new version still implements std::allocator, and throws bad_alloc.
The new version uses `FMT_THROW` macro instead of a bare throw. The article says "One obvious problem is exceptions and those can be disabled via FMT_THROW, e.g. by defining it to abort". If you check the `g++` invocation, that's exactly what the author does.
Yes they could have just defined their own global operator new/delete to have a micro-runtime. Same as you'd do if you were doing a kernel in C++. Super easy, barely an inconvenience
Notably I thought the issue would be the throwing of `std::bad_alloc`, but the new version still implements std::allocator, and throws bad_alloc.
And so I assume the issue is that the global `operator new` is concrete (it just takes the size of the allocation), thus you need to link to the C++ runtime just to get that function? In which case you might be able to get the same gains by redefining the global `operator new` and `operator delete`, without touching the allocator.
Alternatively, you might be able to statically link the C++ runtime and have DCE take care of the rest.