mirror of
https://github.com/irmen/prog8.git
synced 2024-08-15 03:29:16 +00:00
381 lines
21 KiB
Python
381 lines
21 KiB
Python
"""
|
|
Programming Language for 6502/6510 microprocessors, codename 'Sick'
|
|
This is the optimizer that applies various optimizations to the parse tree,
|
|
eliminates statements that have no effect, optimizes calculations etc.
|
|
|
|
Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
|
|
"""
|
|
|
|
from typing import List, no_type_check, Union
|
|
from .datatypes import DataType
|
|
from .plyparse import *
|
|
from .plylex import print_warning, print_bold
|
|
from .constantfold import ConstantFold
|
|
|
|
|
|
class Optimizer:
|
|
def __init__(self, mod: Module) -> None:
|
|
self.num_warnings = 0
|
|
self.module = mod
|
|
self.optimizations_performed = False
|
|
self.constant_folder = ConstantFold(self.module)
|
|
|
|
def optimize(self) -> None:
|
|
self.num_warnings = 0
|
|
self.optimizations_performed = True
|
|
# keep optimizing as long as there were changes made
|
|
while self.optimizations_performed:
|
|
self.optimizations_performed = False
|
|
self._optimize()
|
|
# remaining optimizations that have to be done just once:
|
|
self.remove_unused_subroutines()
|
|
self.remove_empty_blocks()
|
|
|
|
def _optimize(self) -> None:
|
|
self.constant_folder.fold_constants(True) # perform constant folding and simple expression optimization
|
|
# @todo expression optimization: reduce expression nesting / flattening of parenthesis
|
|
# @todo expression optimization: simplify logical expression when a term makes it always true or false
|
|
# @todo expression optimization: optimize some simple multiplications into shifts (A*=8 -> A<<3)
|
|
self.create_aug_assignments()
|
|
self.optimize_assignments()
|
|
self.remove_superfluous_assignments()
|
|
self.combine_assignments_into_multi()
|
|
self.optimize_multiassigns()
|
|
# @todo optimize addition with self into shift 1 (A+=A -> A<<=1)
|
|
self.optimize_goto_compare_with_zero()
|
|
self.join_incrdecrs()
|
|
# @todo remove gotos with conditions that are always false
|
|
# @todo remove loops with conditions that are always empty/false
|
|
# @todo analyse for unreachable code and remove that (f.i. code after goto or return that has no label so can never be jumped to)
|
|
|
|
def join_incrdecrs(self) -> None:
|
|
for scope in self.module.all_nodes(Scope):
|
|
incrdecrs = [] # type: List[IncrDecr]
|
|
target = None
|
|
for node in list(scope.nodes):
|
|
if isinstance(node, IncrDecr):
|
|
if target is None:
|
|
target = node.target
|
|
incrdecrs.append(node)
|
|
continue
|
|
if self._same_target(target, node.target):
|
|
incrdecrs.append(node)
|
|
continue
|
|
if len(incrdecrs) > 1:
|
|
# optimize...
|
|
replaced = False
|
|
total = 0
|
|
for i in incrdecrs:
|
|
if i.operator == "++":
|
|
total += i.howmuch
|
|
else:
|
|
total -= i.howmuch
|
|
if total == 0:
|
|
replaced = True
|
|
for x in incrdecrs:
|
|
scope.remove_node(x)
|
|
else:
|
|
is_float = False
|
|
if isinstance(target, SymbolName):
|
|
symdef = target.my_scope().lookup(target.name)
|
|
if isinstance(symdef, VarDef) and symdef.datatype == DataType.FLOAT:
|
|
is_float = True
|
|
elif isinstance(target, Dereference):
|
|
is_float = target.datatype == DataType.FLOAT
|
|
if is_float:
|
|
replaced = True
|
|
for x in incrdecrs[1:]:
|
|
scope.remove_node(x)
|
|
incrdecr = self._make_incrdecr(incrdecrs[0], target, abs(total), "++" if total >= 0 else "--")
|
|
scope.replace_node(incrdecrs[0], incrdecr)
|
|
elif 0 < total <= 255:
|
|
replaced = True
|
|
for x in incrdecrs[1:]:
|
|
scope.remove_node(x)
|
|
incrdecr = self._make_incrdecr(incrdecrs[0], target, total, "++")
|
|
scope.replace_node(incrdecrs[0], incrdecr)
|
|
elif -255 <= total < 0:
|
|
replaced = True
|
|
total = -total
|
|
for x in incrdecrs[1:]:
|
|
scope.remove_node(x)
|
|
incrdecr = self._make_incrdecr(incrdecrs[0], target, total, "--")
|
|
scope.replace_node(incrdecrs[0], incrdecr)
|
|
if replaced:
|
|
self.optimizations_performed = True
|
|
self.num_warnings += 1
|
|
print_warning("{}: merged a sequence of incr/decrs or augmented assignments".format(incrdecrs[0].sourceref))
|
|
incrdecrs.clear()
|
|
target = None
|
|
if isinstance(node, IncrDecr):
|
|
incrdecrs.append(node)
|
|
target = node.target
|
|
|
|
def _same_target(self, node1: Union[TargetRegisters, Register, SymbolName, Dereference],
|
|
node2: Union[TargetRegisters, Register, SymbolName, Dereference]) -> bool:
|
|
if isinstance(node1, Register) and isinstance(node2, Register) and node1.name == node2.name:
|
|
return True
|
|
if isinstance(node1, SymbolName) and isinstance(node2, SymbolName) and node1.name == node2.name:
|
|
return True
|
|
if isinstance(node1, Dereference) and isinstance(node2, Dereference) and node1.operand == node2.operand:
|
|
return True
|
|
return False
|
|
|
|
@no_type_check
|
|
def create_aug_assignments(self) -> None:
|
|
# create augmented assignments from regular assignment that only refers to the lvalue
|
|
# A=A+10, A=10+A -> A+=10, A=A*4, A=4*A -> A*=4, etc
|
|
for assignment in self.module.all_nodes(Assignment):
|
|
if len(assignment.left.nodes) > 1:
|
|
continue
|
|
if not isinstance(assignment.right, ExpressionWithOperator) or assignment.right.unary:
|
|
continue
|
|
expr = assignment.right
|
|
if expr.operator in ('-', '/', '//', '**', '<<', '>>', '&'): # non-associative operators
|
|
if isinstance(expr.right, (LiteralValue, SymbolName)) and self._same_target(assignment.left.nodes[0], expr.left):
|
|
num_val = expr.right.const_value()
|
|
operator = expr.operator + '='
|
|
aug_assign = self._make_aug_assign(assignment, assignment.left.nodes[0], num_val, operator)
|
|
assignment.my_scope().replace_node(assignment, aug_assign)
|
|
self.optimizations_performed = True
|
|
continue
|
|
if expr.operator not in ('+', '*', '|', '^'): # associative operators
|
|
continue
|
|
if isinstance(expr.right, (LiteralValue, SymbolName)) and self._same_target(assignment.left.nodes[0], expr.left):
|
|
num_val = expr.right.const_value()
|
|
operator = expr.operator + '='
|
|
aug_assign = self._make_aug_assign(assignment, assignment.left.nodes[0], num_val, operator)
|
|
assignment.my_scope().replace_node(assignment, aug_assign)
|
|
self.optimizations_performed = True
|
|
elif isinstance(expr.left, (LiteralValue, SymbolName)) and self._same_target(assignment.left.nodes[0], expr.right):
|
|
num_val = expr.left.const_value()
|
|
operator = expr.operator + '='
|
|
aug_assign = self._make_aug_assign(assignment, assignment.left.nodes[0], num_val, operator)
|
|
assignment.my_scope().replace_node(assignment, aug_assign)
|
|
self.optimizations_performed = True
|
|
|
|
def remove_superfluous_assignments(self) -> None:
|
|
# remove consecutive assignment statements to the same target, only keep the last value (only if its a constant!)
|
|
# this is NOT done for memory mapped variables because these often represent a volatile register of some sort!
|
|
for scope in self.module.all_nodes(Scope):
|
|
prev_node = None # type: AstNode
|
|
for node in list(scope.nodes):
|
|
if isinstance(node, Assignment) and isinstance(prev_node, Assignment):
|
|
if isinstance(node.right, (LiteralValue, Register)) and node.left.same_targets(prev_node.left):
|
|
if not node.left.has_memvalue():
|
|
scope.remove_node(prev_node)
|
|
self.optimizations_performed = True
|
|
self.num_warnings += 1
|
|
print_warning("{}: removed superfluous assignment".format(prev_node.sourceref))
|
|
prev_node = node
|
|
|
|
@no_type_check
|
|
def optimize_assignments(self) -> None:
|
|
# remove assignment statements that do nothing (A=A)
|
|
# remove augmented assignments that have no effect (x+=0, x-=0, x/=1, x//=1, x*=1)
|
|
# convert augmented assignments to simple incr/decr if possible (A+=10 => A++ by 10)
|
|
# simplify some calculations (x*=0, x**=0) to simple constant value assignment
|
|
# @todo remove or simplify logical aug assigns like A |= 0, A |= true, A |= false (or perhaps turn them into byte values first?)
|
|
for assignment in self.module.all_nodes():
|
|
if isinstance(assignment, Assignment):
|
|
if all(lv == assignment.right for lv in assignment.left.nodes):
|
|
assignment.my_scope().remove_node(assignment)
|
|
self.optimizations_performed = True
|
|
self.num_warnings += 1
|
|
print_warning("{}: removed statement that has no effect".format(assignment.sourceref))
|
|
elif isinstance(assignment, AugAssignment):
|
|
if isinstance(assignment.right, LiteralValue) and isinstance(assignment.right.value, (int, float)):
|
|
if assignment.right.value == 0:
|
|
if assignment.operator in ("+=", "-=", "|=", "<<=", ">>=", "^="):
|
|
self.num_warnings += 1
|
|
print_warning("{}: removed statement that has no effect".format(assignment.sourceref))
|
|
assignment.my_scope().remove_node(assignment)
|
|
self.optimizations_performed = True
|
|
elif assignment.operator == "*=":
|
|
self.num_warnings += 1
|
|
print_warning("{}: statement replaced by = 0".format(assignment.sourceref))
|
|
new_assignment = self._make_new_assignment(assignment, 0)
|
|
assignment.my_scope().replace_node(assignment, new_assignment)
|
|
self.optimizations_performed = True
|
|
elif assignment.operator == "**=":
|
|
self.num_warnings += 1
|
|
print_warning("{}: statement replaced by = 1".format(assignment.sourceref))
|
|
new_assignment = self._make_new_assignment(assignment, 1)
|
|
assignment.my_scope().replace_node(assignment, new_assignment)
|
|
self.optimizations_performed = True
|
|
if assignment.right.value >= 8 and assignment.operator in ("<<=", ">>="):
|
|
print("{}: shifting result is always zero".format(assignment.sourceref))
|
|
new_stmt = Assignment(sourceref=assignment.sourceref)
|
|
new_stmt.nodes.append(AssignmentTargets(nodes=[assignment.left], sourceref=assignment.sourceref))
|
|
new_stmt.nodes.append(LiteralValue(value=0, sourceref=assignment.sourceref))
|
|
assignment.my_scope().replace_node(assignment, new_stmt)
|
|
self.optimizations_performed = True
|
|
if assignment.operator in ("+=", "-=") and 0 < assignment.right.value < 256:
|
|
howmuch = assignment.right
|
|
if howmuch.value not in (0, 1):
|
|
_, howmuch = coerce_constant_value(datatype_of(assignment.left, assignment.my_scope()),
|
|
howmuch, assignment.sourceref)
|
|
new_stmt = IncrDecr(operator="++" if assignment.operator == "+=" else "--",
|
|
howmuch=howmuch.value, sourceref=assignment.sourceref)
|
|
new_stmt.target = assignment.left
|
|
new_stmt.target.parent = new_stmt
|
|
assignment.my_scope().replace_node(assignment, new_stmt)
|
|
self.optimizations_performed = True
|
|
if assignment.right.value == 1 and assignment.operator in ("/=", "//=", "*="):
|
|
self.num_warnings += 1
|
|
print_warning("{}: removed statement that has no effect".format(assignment.sourceref))
|
|
assignment.my_scope().remove_node(assignment)
|
|
self.optimizations_performed = True
|
|
|
|
@no_type_check
|
|
def _make_new_assignment(self, old_aug_assignment: AugAssignment, constantvalue: int) -> Assignment:
|
|
new_assignment = Assignment(sourceref=old_aug_assignment.sourceref)
|
|
new_assignment.parent = old_aug_assignment.parent
|
|
left = AssignmentTargets(nodes=[old_aug_assignment.left], sourceref=old_aug_assignment.sourceref)
|
|
left.parent = new_assignment
|
|
new_assignment.nodes.append(left)
|
|
value = LiteralValue(value=constantvalue, sourceref=old_aug_assignment.sourceref)
|
|
value.parent = new_assignment
|
|
new_assignment.nodes.append(value)
|
|
return new_assignment
|
|
|
|
@no_type_check
|
|
def _make_aug_assign(self, old_assign: Assignment, target: Union[TargetRegisters, Register, SymbolName, Dereference],
|
|
value: Union[int, float], operator: str) -> AugAssignment:
|
|
assert isinstance(target, (TargetRegisters, Register, SymbolName, Dereference))
|
|
a = AugAssignment(operator=operator, sourceref=old_assign.sourceref)
|
|
a.nodes.append(target)
|
|
target.parent = a
|
|
lv = LiteralValue(value=value, sourceref=old_assign.sourceref)
|
|
a.nodes.append(lv)
|
|
lv.parent = a
|
|
a.parent = old_assign.parent
|
|
return a
|
|
|
|
@no_type_check
|
|
def _make_incrdecr(self, old_stmt: AstNode, target: Union[TargetRegisters, Register, SymbolName, Dereference],
|
|
howmuch: Union[int, float], operator: str) -> IncrDecr:
|
|
assert isinstance(target, (TargetRegisters, Register, SymbolName, Dereference))
|
|
a = IncrDecr(operator=operator, howmuch=howmuch, sourceref=old_stmt.sourceref)
|
|
a.nodes.append(target)
|
|
target.parent = a
|
|
a.parent = old_stmt.parent
|
|
return a
|
|
|
|
def combine_assignments_into_multi(self) -> None:
|
|
# fold multiple consecutive assignments with the same rvalue into one multi-assignment
|
|
for scope in self.module.all_nodes(Scope):
|
|
rvalue = None
|
|
assignments = [] # type: List[Assignment]
|
|
for stmt in list(scope.nodes):
|
|
if isinstance(stmt, Assignment):
|
|
if assignments:
|
|
if stmt.right == rvalue:
|
|
assignments.append(stmt)
|
|
continue
|
|
elif len(assignments) > 1:
|
|
# replace the first assignment by a multi-assign with all the others
|
|
for assignment in assignments[1:]:
|
|
print("{}: joined with previous assignment".format(assignment.sourceref))
|
|
assignments[0].left.nodes.extend(assignment.left.nodes)
|
|
scope.remove_node(assignment)
|
|
self.optimizations_performed = True
|
|
rvalue = None
|
|
assignments.clear()
|
|
else:
|
|
rvalue = stmt.right
|
|
assignments.append(stmt)
|
|
else:
|
|
rvalue = None
|
|
assignments.clear()
|
|
|
|
@no_type_check
|
|
def optimize_multiassigns(self) -> None:
|
|
# optimize multi-assign statements (remove duplicate targets, optimize order)
|
|
for assignment in self.module.all_nodes(Assignment):
|
|
if len(assignment.left.nodes) > 1:
|
|
# remove duplicates
|
|
lvalues = set(assignment.left.nodes)
|
|
if len(lvalues) != len(assignment.left.nodes):
|
|
print("{}: removed duplicate assignment targets".format(assignment.sourceref))
|
|
# @todo change order: first registers, then zp addresses, then non-zp addresses, then the rest (if any)
|
|
assignment.left.nodes = list(lvalues)
|
|
self.optimizations_performed = True
|
|
|
|
@no_type_check
|
|
def remove_unused_subroutines(self) -> None:
|
|
# some symbols are used by the emitted assembly code from the code generator,
|
|
# and should never be removed or the assembler will fail
|
|
never_remove = {"c64.FREADUY", "c64.FTOMEMXY", "c64.FADD", "c64.FSUB",
|
|
"c64flt.GIVUAYF", "c64flt.copy_mflt", "c64flt.float_add_one", "c64flt.float_sub_one",
|
|
"c64flt.float_add_SW1_to_XY", "c64flt.float_sub_SW1_from_XY"}
|
|
num_discarded = 0
|
|
for sub in self.module.all_nodes(Subroutine):
|
|
usages = self.module.subroutine_usage[(sub.parent.name, sub.name)]
|
|
if not usages and sub.parent.name + '.' + sub.name not in never_remove:
|
|
sub.parent.remove_node(sub)
|
|
num_discarded += 1
|
|
# if num_discarded:
|
|
# print("discarded {:d} unused subroutines".format(num_discarded))
|
|
|
|
@no_type_check
|
|
def optimize_goto_compare_with_zero(self) -> None:
|
|
# a conditional goto that compares a value with zero will be simplified
|
|
# the comparison operator and rvalue (0) will be removed and the if-status changed accordingly
|
|
for goto in self.module.all_nodes(Goto):
|
|
if isinstance(goto.condition, Expression):
|
|
pass # @todo optimize goto conditionals
|
|
# if cond and isinstance(cond.rvalue, (int, float)) and cond.rvalue.value == 0:
|
|
# simplified = False
|
|
# if cond.ifstatus in ("true", "ne"):
|
|
# if cond.comparison_op == "==":
|
|
# # if_true something == 0 -> if_not something
|
|
# cond.ifstatus = "not"
|
|
# cond.comparison_op, cond.rvalue = "", None
|
|
# simplified = True
|
|
# elif cond.comparison_op == "!=":
|
|
# # if_true something != 0 -> if_true something
|
|
# cond.comparison_op, cond.rvalue = "", None
|
|
# simplified = True
|
|
# elif cond.ifstatus in ("not", "eq"):
|
|
# if cond.comparison_op == "==":
|
|
# # if_not something == 0 -> if_true something
|
|
# cond.ifstatus = "true"
|
|
# cond.comparison_op, cond.rvalue = "", None
|
|
# simplified = True
|
|
# elif cond.comparison_op == "!=":
|
|
# # if_not something != 0 -> if_not something
|
|
# cond.comparison_op, cond.rvalue = "", None
|
|
# simplified = True
|
|
# if simplified:
|
|
# print("{}: simplified comparison with zero".format(stmt.sourceref))
|
|
|
|
def remove_empty_blocks(self) -> None:
|
|
# remove blocks without name and without address, or that are empty
|
|
for node in self.module.all_nodes():
|
|
if isinstance(node, (Subroutine, Block)):
|
|
if not node.scope:
|
|
continue
|
|
if all(isinstance(n, Directive) for n in node.scope.nodes):
|
|
empty = True
|
|
for n in node.scope.nodes:
|
|
empty = empty and n.name not in {"asmbinary", "asminclude"}
|
|
if empty:
|
|
self.num_warnings += 1
|
|
print_warning("ignoring empty block or subroutine", node.sourceref)
|
|
assert isinstance(node.parent, (Block, Module))
|
|
node.my_scope().nodes.remove(node)
|
|
if isinstance(node, Block):
|
|
if not node.name and node.address is None:
|
|
self.num_warnings += 1
|
|
print_warning("ignoring block without name and address", node.sourceref)
|
|
assert isinstance(node.parent, Module)
|
|
node.my_scope().nodes.remove(node)
|
|
|
|
|
|
def optimize(mod: Module) -> None:
|
|
opt = Optimizer(mod)
|
|
opt.optimize()
|
|
if opt.num_warnings:
|
|
print_bold("There are {:d} optimization warnings.".format(opt.num_warnings))
|