Various Language Architecture Questions

[frankgerlach@gmail.com]

Hello,
I am contemplating to create a new language, which is supposed to be as
fast as C++, but as safe as Java.
Maybe Ada is already fulfilling these requirements, so I have a few
questions:
Is is possible to safely allocate objects on the stack and then pass a
pointer to these objects to a procedure ?
(The stack is very fast, but I cannot tolerate invalid references from
the heap or from "older" stack regions)
Are the common Ada runtimes performing range checks on Arrays,
including "casted" pointers ?
(Typecasting is necessary for high-performance access, but I want to be
safely in bounds of the array all the time)
Also, it should be forbidden (by compiler or runtime) to cast a type
that contains a pointer to a different type. Does Ada support this ? (I
must secure pointers in order to have only valid pointers in the
system. Invalid pointers introduce random errors or security problems
for a sandbox execution model)