# Holds globals, and (for now at least), global constants.
# Note that Ruby-like "constants" aren't really - they are "assign-once"
# variables. As such, some of them can be treated as true constants
# (because their value is known at compile time), but some of them are
# not. For now, we'll treat all of them as global variables.
class GlobalScope
attr_accessor :globals
def initialize
@globals = Set.new
end
def get_arg a
return [:global,a] if @globals.member?(a)
return [:addr,a]
end
end
class FuncScope
def initialize func, next_scope = nil
@func = func
@next = next_scope
end
def rest?
@func ? @func.rest? : false
end
def get_arg a
a = a.to_sym
if @func
arg = @func.get_arg(a)
return arg if arg
end
return @next.get_arg(a) if @next
return [:addr,a]
end
end
class LocalVarScope
def initialize locals, next_scope
@next = next_scope
@locals = locals
end
def rest?
@next ? @next.rest? : false
end
def get_arg a
a = a.to_sym
return [:lvar,@locals[a] + (rest? ? 1 : 0)] if @locals.include?(a)
return @next.get_arg(a) if @next
return [:addr,a] # Shouldn't get here normally
end
end
VTableEntry = Struct.new(:name,:realname,:offset,:function)
# Need a global list of vtable offsets since
# we can't usually statically determine what class
# an object belongs to.
class VTableOffsets
def initialize
@vtable = {}
@vtable_max = 1 # Start at 1 since offset 0 is reserved for the vtable pointer for the Class object
# Then we insert the "new" method.
get_offset(:new)
end
def get_offset(name)
name = name.to_sym
if !@vtable[name]
@vtable[name] = @vtable_max
@vtable_max += 1
end
return @vtable[name]
end
def max
@vtable_max
end
end
class ClassScope
attr_reader :name,:vtable
def initialize next_scope,name,offsets
@next = next_scope
@name = name
@vtable = {}
@vtableoffsets = offsets
end
def rest?
false
end
def get_arg a
return @next.get_arg(a) if @next
return [:addr,a]
end
def klass_size
@vtableoffsets.max * Emitter::PTR_SIZE
end
def add_vtable_entry(name)
@vtable[name] ||= VTableEntry.new
v = @vtable[name]
v.name = name.to_s
v.offset = @vtableoffsets.get_offset(name) if !v.offset
return v
end
def set_vtable_entry(name,realname,f)
v = add_vtable_entry(name)
v.realname = realname
v.function = f
end
end
