(b) don't override the delete operator (on top of the regular conditions for
stack allocation that also apply to arrays, structs, etc.).
The "no destructor" clause is not strictly necessary, but calling them at the
right time would be tricky to say the least; it would involve, among other
things, "manually" inserting a try-finally block around anything that might
throw exceptions not caught in the current function.
Note: objects with custom new operators are automatically ignored because they
don't use the regular allocation runtime call, so there's no need to pay special
attention to them.
to generate asm for code with metadata globals.
This new pass is used as a workaround: it strips metadata from the module before
it reaches the code generator.
Obviously, this is disabled if LLVM doesn't support metadata.
This one promotes GC allocations to stack memory when it can determine it's safe
to do so.
Not all GC calls are recognized yet (in fact only one *is* recognized for now).
Needs metadata, so disabled for LLVM versions that don't support it.
It uses the machinery of the standard -simplify-libcalls pass, but optimizes
calls to the D runtime instead of calls to C libraries.
At the moment, these optimizations are implemented by this pass:
- Avoid the runtime call for `arr.length = newlen` if it can determine that
the new length isn't longer than the old one.
- Ditto for `cast(T[]) arr` if it will clearly always succeed.
(e.g. if the length of the original array is zero, or if the old element
size is a multiple of the new element size)
