Reworking if statement

Using 2 phase approach
Flattening tbd
This commit is contained in:
Torsten Ruger 2017-09-04 21:00:08 +03:00
parent db1549e0ee
commit dab4e74659
5 changed files with 47 additions and 26 deletions

9
lib/mom/check.rb Normal file
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@ -0,0 +1,9 @@
module Mom
# A base class for conditions in MOM
# Just a marker, no real functionality for now
class Check < Instruction
end
end

14
lib/mom/if_statement.rb Normal file
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@ -0,0 +1,14 @@
module Mom
class IfStatement < Instruction
attr_reader :condition , :if_true , :if_false
attr_accessor :hoisted
def initialize( cond , if_true , if_false = nil)
@condition = cond
@if_true = if_true
@if_false = if_false
end
end
end

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@ -2,10 +2,17 @@ module Mom
# Base class for MOM instructions # Base class for MOM instructions
class Instruction class Instruction
attr :next_instruction
# flattening will change the structure from a tree to a linked list (and use
# next_instruction to do so)
def flatten
raise "not implemented"
end
end end
# basically a label # A label with a name
class Noop class Label
attr_reader :name attr_reader :name
def initialize(name) def initialize(name)
@name = name @name = name
@ -16,6 +23,7 @@ module Mom
end end
require_relative "simple_call" require_relative "simple_call"
require_relative "if_statement"
require_relative "truth_check" require_relative "truth_check"
require_relative "jump" require_relative "jump"
require_relative "slot_load" require_relative "slot_load"

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@ -1,3 +1,5 @@
require_relative "check"
module Mom module Mom
# The funny thing about the ruby truth is that is is anything but false or nil # The funny thing about the ruby truth is that is is anything but false or nil
@ -5,17 +7,11 @@ module Mom
# To implement the normal ruby logic, we check for false or nil and jump # To implement the normal ruby logic, we check for false or nil and jump
# to the false branch. true_block follows implicitly # to the false branch. true_block follows implicitly
# #
# The class only carries the blocks for analysis, and does class TruthCheck < Check
# - NOT imply any order attr_reader :condition
# - will not "handle" the blocks in subsequent processing.
#
class TruthCheck < Instruction
attr_reader :condition , :true_block , :false_block , :merge_block
def initialize(condition , true_block , false_block , merge_block) def initialize(condition)
@condition , @true_block , @false_block , @merge_block = condition , true_block , false_block , merge_block @condition = condition
end end
end end
end end

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@ -10,19 +10,19 @@ module Vool
end end
def to_mom( method ) def to_mom( method )
merge = Mom::Noop.new(:merge) if_true = @if_true.to_mom( method )
if_true = add_jump(@if_true.to_mom( method ) , merge) if_false = @if_false.to_mom( method )
if_false = add_jump(@if_false.to_mom( method ) , merge) condition , hoisted = hoist_condition( method )
cond = hoist_condition( method ) check = Mom::IfStatement.new( Mom::TruthCheck.new(condition) , if_true , if_false )
check = Mom::TruthCheck.new( cond.pop , if_true , if_false , merge) check.hoisted = hoisted.to_mom(method) if hoisted
[ *cond , check , if_true , if_false , merge ] check
end end
def hoist_condition( method ) def hoist_condition( method )
return [@condition] if @condition.is_a?(Vool::Named) return [@condition] if @condition.is_a?(Vool::Named)
local = method.create_tmp local = method.create_tmp
assign = LocalAssignment.new( local , @condition).to_mom(method) assign = LocalAssignment.new( local , @condition)
[assign , Vool::LocalVariable.new(local)] [Vool::LocalVariable.new(local) , assign]
end end
def collect(arr) def collect(arr)
@ -44,11 +44,5 @@ module Vool
@if_true != nil @if_true != nil
end end
private
def add_jump( block , merge)
block = [block] unless block.is_a?(Array)
block << Mom::Jump.new(merge)
block
end
end end
end end