This was detected by valgrind. I think GCC still does the right
thing, but the C++ spec allows the compiler to do something
stupid... like crash or only delete the first entry in the array.
Create separate subclasses of ir_dereference for variable, array, and
record dereferences. As a side effect, array and record dereferences
no longer point to ir_variable objects directly. Instead they each
point to an ir_dereference_variable object.
This is the first of several steps in the refactoring process. The
intention is that ir_dereference will eventually become an abstract
base class.
This caused a nasty bug where the function inliner would create new
variables for each of the formal parameters, but the body would still
reference the old copies.
This was highly visible since the dead code eliminator (rightly) removed
the new declarations, leading to printed IR that referenced non-existent
variable names.
Now, ir_function is emitted as part of the IR instructions, rather than
simply existing in the symbol table. Individual ir_function_signatures
are not emitted themselves, but only as part of ir_function.
