def regenerate_ir(self):
"""Regenerate Intermediate Representation by inserting phi instructions.
"""
Instruction.reset_counter()
new_ssa = []
nodes_phi_ed = {}
# Creates new instruction for every phi instruction and the old instruction.
# Also creates a new CFG for the old CFG
for instruction in self.ssa:
node = self.label_nodes[instruction.label]
# Generate phi instructions.
if node not in nodes_phi_ed:
for phi in node.phi_functions.values():
new_instruction = Instruction('phi', phi['LHS'], *phi['RHS'])
new_ssa.append(new_instruction)
nodes_phi_ed[node] = True
# Just regenerate the old instructions.
new_instruction = Instruction(
instruction.instruction, instruction.operand1, instruction.operand2)
new_ssa.append(new_instruction)
self.labels_ir_to_ssa[instruction.label] = new_instruction.label
# FIXME: This may be a possible source of error, since this instruction
# may be referring to the result of some 10 instructions before and
# "phi" functions may have been inserted in between. First checkpoint
# if bug appears.
# Post processing to adjust all the instructions whose operands are
# other instruction labels. We are doing a scan again because, we do
# not know how branch instructions behave in the previous processing,
# i.e. if "phi" instruction gets inserted anywhere in the future before
# we regenerate the instruction to which this branch statement targets.
for instruction in new_ssa:
operand1 = instruction.operand1
operand2 = instruction.operand2
if isinstance(instruction.operand1, int):
if operand1 in self.labels_ir_to_ssa:
operand1 = self.labels_ir_to_ssa[operand1]
if isinstance(instruction.operand2, int):
if operand2 in self.labels_ir_to_ssa:
operand2 = self.labels_ir_to_ssa[operand2]
instruction.update(operand1=operand1, operand2=operand2)
# Throw away old ssa copy, we don't want it anymore!
self.ssa = new_ssa
def __init__(self,node=None):
Instruction.__init__(self)
