def precolor(node):
if classGuard(node, Assign, Phi):
sym = extractSymbol(node)
if not sym.has_key('precolor'):
sym['precolor'] = None
elif isinstance(node, Div) and isinstance(node.left, Symbol):
node.left['precolor'] = eax
elif isinstance(node, Function):
# This clause pre-colors function arguments with their position on
# the stack relative to the %ebp register. The first argument
# starts 8 bytes above the base pointer. Each successive argument is
# 4 bytes above that.
offset = 8
for sym in node.argSymbols:
sym['precolor'] = Mem(offset, 'up', True)
#Advance to the next argument offset.
offset += 4
elif isinstance(node, Return):
# Values are returned from functions in the %eax register.
node['precolor'] = eax
for child in node:
precolor(child)
def eliminateDeadStores(node, klass=0):
newChildren = []
if isinstance(node, Class):
klass += 1
for child in node:
newChildren.append(eliminateDeadStores(child, klass))
node.setChildren(flatten(newChildren))
if isinstance(node, Assign):
sym = extractSymbol(node.var)
if sym['reads'] == 0 and klass == 0:
if classGuard(node.exp, Class, FunctionCall):
return node
else:
return None
else:
return node
elif isinstance(node, Phi) and node.target['reads'] == 0:
return None
else:
return node
def precolor(node):
if classGuard(node, Assign, Phi):
sym = extractSymbol(node)
if not sym.has_key('precolor'):
sym['precolor'] = None
elif isinstance(node, Div) and isinstance(node.left, Symbol):
node.left['precolor'] = eax
elif isinstance(node, Function):
# This clause pre-colors function arguments with their position on
# the stack relative to the %ebp register. The first argument
# starts 8 bytes above the base pointer. Each successive argument is
# 4 bytes above that.
offset = 8
for sym in node.argSymbols:
sym['precolor'] = Mem(offset, 'up', True)
#Advance to the next argument offset.
offset += 4
elif isinstance(node, Return):
# Values are returned from functions in the %eax register.
node['precolor'] = eax
for child in node:
precolor(child)
def reads(node):
if classGuard(node, Assign, Phi):
sym = extractSymbol(node)
if not sym.has_key('reads'):
sym['reads'] = 0
elif isinstance(node, Function):
for sym in node.argSymbols:
sym['reads'] = 0
elif isinstance(node, Symbol):
# This is kind of ugly, but because of Python's scoping rules we can
# read from a variable before it is 'in scope.'
if node.has_key('reads'):
node['reads'] += 1
else:
node['reads'] = 1
elif isinstance(node, Subscript) and isinstance(node.symbol, Symbol):
# This little hack is here to take care of cases where subscripts are
# applied to literal values. After the flatten transformation this
# branch will be taken whenever we see a subscript.
node.symbol['reads'] += 1
for child in node:
reads(child)
def eliminateDeadStores(node, klass = 0): newChildren = [] if isinstance(node, Class): klass += 1 for child in node: newChildren.append(eliminateDeadStores(child, klass)) node.setChildren(flatten(newChildren)) if isinstance(node, Assign): sym = extractSymbol(node.var) if sym['reads'] == 0 and klass == 0: if classGuard(node.exp, Class, FunctionCall): return node else: return None else: return node elif isinstance(node, Phi) and node.target['reads'] == 0: return None else: return node
def spans(node, count=0, alive=None):
inc = 1
if isinstance(node, Module):
alive = {}
# Count the spans over our children.
for child in node:
subInc = spans(child, count, alive)
inc += subInc
count += subInc
if classGuard(node, Assign, Phi):
# Due to SSA form we know this variable isn't already alive.
sym = extractSymbol(node)
sym['spans-funcall'] = False
if sym in node['post-alive']:
alive[sym] = count
else:
sym['span-start'] = sym['span-end'] = count
sym['span-length'] = 0
elif isinstance(node, Function):
for sym in node.argSymbols:
sym['spans-funcall'] = False
if sym in node['post-alive']:
alive[sym] = count
else:
sym['span-start'] = sym['span-end'] = count
sym['span-length'] = 0
elif isinstance(node, FunctionCall):
#Mark functions that span this function call.
for sym in node['pre-alive']:
if sym in node['post-alive']:
sym['spans-funcall'] = True
# This is here so we don't change the alive list while we are iterating
# through it.
deletes = []
# Symbols don't have any pre/post-alive information due to their Singleton
# nature.
if not classGuard(node, Name, String, Symbol):
for sym in alive:
if isinstance(node, Function) or sym not in node['post-alive']:
sym['span-start'] = alive[sym]
sym['span-end'] = count - 1
sym['span-length'] = sym['span-end'] - sym['span-start']
deletes.append(sym)
for sym in deletes:
del alive[sym]
return inc
def spans(node, count = 0, alive = None):
inc = 1
if isinstance(node, Module):
alive = {}
# Count the spans over our children.
for child in node:
subInc = spans(child, count, alive)
inc += subInc
count += subInc
if classGuard(node, Assign, Phi):
# Due to SSA form we know this variable isn't already alive.
sym = extractSymbol(node)
sym['spans-funcall'] = False
if sym in node['post-alive']:
alive[sym] = count
else:
sym['span-start'] = sym['span-end'] = count
sym['span-length'] = 0
elif isinstance(node, Function):
for sym in node.argSymbols:
sym['spans-funcall'] = False
if sym in node['post-alive']:
alive[sym] = count
else:
sym['span-start'] = sym['span-end'] = count
sym['span-length'] = 0
elif isinstance(node, FunctionCall):
#Mark functions that span this function call.
for sym in node['pre-alive']:
if sym in node['post-alive']:
sym['spans-funcall'] = True
# This is here so we don't change the alive list while we are iterating
# through it.
deletes = []
# Symbols don't have any pre/post-alive information due to their Singleton
# nature.
if not classGuard(node, Name, String, Symbol):
for sym in alive:
if isinstance(node, Function) or sym not in node['post-alive']:
sym['span-start'] = alive[sym]
sym['span-end' ] = count - 1
sym['span-length'] = sym['span-end'] - sym['span-start']
deletes.append(sym)
for sym in deletes:
del alive[sym]
return inc
def liveness(node, alive=[]):
if isinstance(node, Module):
alive = []
if not classGuard(node, Name, String, Symbol):
node['pre-alive'] = set(alive)
if isinstance(node, Function):
for sym in node.argSymbols:
#Functions might have arguments that are never read.
if sym['reads'] > 0:
sym['tmp'] = sym['reads']
alive.append(sym)
for child in node:
liveness(child, alive)
if classGuard(node, Assign, Phi):
sym = extractSymbol(node)
if not sym.has_key('tmp'):
sym['tmp'] = sym['reads']
alive.append(sym)
elif isinstance(node, Symbol) or (isinstance(node, Subscript)
and isinstance(node.symbol, Symbol)):
sym = extractSymbol(node)
if sym.has_key('tmp'):
sym['tmp'] -= 1
if sym['tmp'] == 0:
alive.remove(sym)
else:
sym['tmp'] = sym['reads']
alive.append(sym)
if not classGuard(node, Name, String, Symbol):
node['post-alive'] = set(alive)
def weight(node, depth = 0.0): if isinstance(node, Assign): sym = extractSymbol(node) sym['weight'] = 1.0 + (10.0 ** depth) sym['tmp'] = sym['reads'] elif isinstance(node, Symbol): node['weight'] += 1.0 + (10.0 ** depth) node['tmp'] -= 1 if node['tmp'] == 0: node['weight'] = node['weight'] / float(node['span-length']) for child in node: if isinstance(node, BasicBlock): weight(child, depth + 1.0) else: weight(child, depth)
def related(node):
if isinstance(node, Assign):
sym0 = extractSymbol(node.var)
sym0['related'] = set()
if not sym0.has_key('phi-related'):
sym0['phi-related'] = set()
if isinstance(node.exp, Symbol):
sym1 = node.exp
if not sym1 in node['post-alive']:
sym0['related'].add(sym1)
elif isinstance(node.exp, BinOp):
if isinstance(node.exp.left, Symbol):
# Mark the left symbol as related to the target symbol.
sym1 = node.exp.left
if sym1 not in node['post-alive']:
sym0['related'].add(sym1)
if classGuard(node.exp, Add, Mul) and isinstance(node.exp.right, Symbol):
# Mark the right symbol as related to the target symbol if
# this is an Add or Mul node.
sym1 = node.exp.right
if sym1 not in node['post-alive']:
sym0['related'].add(sym1)
elif isinstance(node.exp, UnaryOp) and isinstance(node.exp.operand, Symbol):
sym1 = node.exp.operand
if not sym1 in node['post-alive']:
sym0['related'].add(sym1)
elif isinstance(node, Function):
for sym in node.argSymbols:
sym['related'] = set()
sym['phi-related'] = set()
elif isinstance(node, Phi):
fullSet = set()
syms = set([node.target] + node.srcs)
while len(syms) > 0:
sym = syms.pop()
if sym.has_key('phi-related'):
syms |= sym['phi-related'] - fullSet
fullSet.add(sym)
for sym in fullSet:
if sym.has_key('phi-related'):
sym['phi-related'] |= fullSet
else:
sym['phi-related'] = fullSet
for child in node:
related(child)