def make_byte_array_copier(destination, source, pos=None):
if not isinstance(source.typ, (ByteArrayType, NullType)):
raise TypeMismatchException(
"Can only set a byte array to another byte array", pos)
if isinstance(
source.typ,
ByteArrayType) and source.typ.maxlen > destination.typ.maxlen:
raise TypeMismatchException(
"Cannot cast from greater max-length %d to shorter max-length %d" %
(source.typ.maxlen, destination.typ.maxlen))
# Special case: memory to memory
if source.location == "memory" and destination.location == "memory":
gas_calculation = GAS_IDENTITY + GAS_IDENTITYWORD * (
ceil32(source.typ.maxlen) // 32)
o = LLLnode.from_list([
'with', '_source', source,
[
'with', '_sz', ['add', 32, ['mload', '_source']],
[
'assert',
[
'call', ['add', 18, ['div', '_sz', 10]], 4, 0,
'_source', '_sz', destination, '_sz'
]
]
]
],
typ=None,
add_gas_estimate=gas_calculation,
annotation='Memory copy')
return o
pos_node = LLLnode.from_list('_pos',
typ=source.typ,
location=source.location)
# Get the length
if isinstance(source.typ, NullType):
length = 1
elif source.location == "memory":
length = ['add', ['mload', '_pos'], 32]
elif source.location == "storage":
length = ['add', ['sload', '_pos'], 32]
pos_node = LLLnode.from_list(['sha3_32', pos_node],
typ=source.typ,
location=source.location)
else:
raise Exception("Unsupported location:" + source.location)
if destination.location == "storage":
destination = LLLnode.from_list(['sha3_32', destination],
typ=destination.typ,
location=destination.location)
# Maximum theoretical length
max_length = 32 if isinstance(source.typ,
NullType) else source.typ.maxlen + 32
return LLLnode.from_list([
'with', '_pos', 0 if isinstance(source.typ, NullType) else source,
make_byte_slice_copier(
destination, pos_node, length, max_length, pos=pos)
],
typ=None)
def __init__(self, value, args=None, typ=None, location=None, pos=None, annotation='', mutable=True, add_gas_estimate=0, valency=0):
if args is None:
args = []
self.value = value
self.args = args
self.typ = typ
assert isinstance(self.typ, NodeType) or self.typ is None, repr(self.typ)
self.location = location
self.pos = pos
self.annotation = annotation
self.mutable = mutable
self.add_gas_estimate = add_gas_estimate
self.as_hex = AS_HEX_DEFAULT
self.valency = valency
# Determine this node's valency (1 if it pushes a value on the stack,
# 0 otherwise) and checks to make sure the number and valencies of
# children are correct. Also, find an upper bound on gas consumption
# Numbers
if isinstance(self.value, int):
self.valency = 1
self.gas = 5
elif isinstance(self.value, str):
# Opcodes and pseudo-opcodes (e.g. clamp)
if self.value.upper() in comb_opcodes:
_, ins, outs, gas = comb_opcodes[self.value.upper()]
self.valency = outs
if len(self.args) != ins:
raise Exception("Number of arguments mismatched: %r %r" % (self.value, self.args))
# We add 2 per stack height at push time and take it back
# at pop time; this makes `break` easier to handle
self.gas = gas + 2 * (outs - ins)
for arg in self.args:
# if arg.valency == 0:
# raise Exception("Can't have a zerovalent argument to an opcode or a pseudo-opcode! %r: %r" % (arg.value, arg))
self.gas += arg.gas
# Dynamic gas cost: 8 gas for each byte of logging data
if self.value.upper()[0:3] == 'LOG' and isinstance(self.args[1].value, int):
self.gas += self.args[1].value * 8
# Dynamic gas cost: non-zero-valued call
if self.value.upper() == 'CALL' and self.args[2].value != 0:
self.gas += 34000
# Dynamic gas cost: filling sstore (ie. not clearing)
elif self.value.upper() == 'SSTORE' and self.args[1].value != 0:
self.gas += 15000
# Dynamic gas cost: calldatacopy
elif self.value.upper() in ('CALLDATACOPY', 'CODECOPY'):
size = 34000
if isinstance(self.args[2].value, int):
size = self.args[2].value
elif isinstance(self.args[2], LLLnode) and len(self.args[2].args) > 0:
size = self.args[2].args / [-1].value
self.gas += ceil32(size) // 32 * 3
# Gas limits in call
if self.value.upper() == 'CALL' and isinstance(self.args[0].value, int):
self.gas += self.args[0].value
# If statements
elif self.value == 'if':
if len(self.args) == 3:
self.gas = self.args[0].gas + max(self.args[1].gas, self.args[2].gas) + 3
if self.args[1].valency != self.args[2].valency:
raise Exception("Valency mismatch between then and else clause: %r %r" % (self.args[1], self.args[2]))
if len(self.args) == 2:
self.gas = self.args[0].gas + self.args[1].gas + 17
if self.args[1].valency:
raise Exception("2-clause if statement must have a zerovalent body: %r" % self.args[1])
if not self.args[0].valency:
raise Exception("Can't have a zerovalent argument as a test to an if statement! %r" % self.args[0])
if len(self.args) not in (2, 3):
raise Exception("If can only have 2 or 3 arguments")
self.valency = self.args[1].valency
# With statements: with <var> <initial> <statement>
elif self.value == 'with':
if len(self.args) != 3:
raise Exception("With statement must have 3 arguments")
if len(self.args[0].args) or not isinstance(self.args[0].value, str):
raise Exception("First argument to with statement must be a variable")
if not self.args[1].valency:
raise Exception("Second argument to with statement (initial value) cannot be zerovalent: %r" % self.args[1])
self.valency = self.args[2].valency
self.gas = sum([arg.gas for arg in self.args]) + 5
# Repeat statements: repeat <index_memloc> <startval> <rounds> <body>
elif self.value == 'repeat':
if len(self.args[2].args) or not isinstance(self.args[2].value, int) or self.args[2].value <= 0:
raise Exception("Number of times repeated must be a constant nonzero positive integer: %r" % self.args[2])
if not self.args[0].valency:
raise Exception("First argument to repeat (memory location) cannot be zerovalent: %r" % self.args[0])
if not self.args[1].valency:
raise Exception("Second argument to repeat (start value) cannot be zerovalent: %r" % self.args[1])
if self.args[3].valency:
raise Exception("Third argument to repeat (clause to be repeated) must be zerovalent: %r" % self.args[3])
self.valency = 0
if self.args[1].value == 'mload' or self.args[1].value == 'sload':
rounds = self.args[2].value
else:
rounds = abs(self.args[2].value - self.args[1].value)
self.gas = rounds * (self.args[3].gas + 50) + 30
# Seq statements: seq <statement> <statement> ...
elif self.value == 'seq':
self.valency = self.args[-1].valency if self.args else 0
self.gas = sum([arg.gas for arg in self.args]) + 30
# Multi statements: multi <expr> <expr> ...
elif self.value == 'multi':
for arg in self.args:
if not arg.valency:
raise Exception("Multi expects all children to not be zerovalent: %r" % arg)
self.valency = sum([arg.valency for arg in self.args])
self.gas = sum([arg.gas for arg in self.args])
# LLL brackets (don't bother gas counting)
elif self.value == 'lll':
self.valency = 1
self.gas = NullAttractor()
# Stack variables
else:
self.valency = 1
self.gas = 5
if self.value == 'seq_unchecked':
self.gas = sum([arg.gas for arg in self.args]) + 30
if self.value == 'if_unchecked':
self.gas = self.args[0].gas + self.args[1].gas + 17
elif self.value is None and isinstance(self.typ, NullType):
self.valency = 1
self.gas = 5
else:
raise Exception("Invalid value for LLL AST node: %r" % self.value)
assert isinstance(self.args, list)
self.gas += self.add_gas_estimate
def pack_logging_data(expected_data, args, context, pos):
# Checks to see if there's any data
if not args:
return ['seq'], 0, None, 0
holder = ['seq']
maxlen = len(args) * 32 # total size of all packed args (upper limit)
requires_dynamic_offset = any(
[isinstance(data.typ, ByteArrayType) for data in expected_data])
if requires_dynamic_offset:
zero_pad_i = context.new_placeholder(
BaseType('uint256')) # Iterator used to zero pad memory.
dynamic_offset_counter = context.new_placeholder(BaseType(32))
dynamic_placeholder = context.new_placeholder(BaseType(32))
else:
dynamic_offset_counter = None
zero_pad_i = None
# Populate static placeholders.
placeholder_map = {}
for i, (arg, data) in enumerate(zip(args, expected_data)):
typ = data.typ
placeholder = context.new_placeholder(BaseType(32))
placeholder_map[i] = placeholder
if not isinstance(typ, ByteArrayType):
holder, maxlen = pack_args_by_32(holder,
maxlen,
arg,
typ,
context,
placeholder,
zero_pad_i=zero_pad_i,
pos=pos)
# Dynamic position starts right after the static args.
if requires_dynamic_offset:
holder.append(
LLLnode.from_list(['mstore', dynamic_offset_counter, maxlen]))
# Calculate maximum dynamic offset placeholders, used for gas estimation.
for i, (arg, data) in enumerate(zip(args, expected_data)):
typ = data.typ
if isinstance(typ, ByteArrayType):
maxlen += 32 + ceil32(typ.maxlen)
if requires_dynamic_offset:
datamem_start = dynamic_placeholder + 32
else:
datamem_start = placeholder_map[0]
# Copy necessary data into allocated dynamic section.
for i, (arg, data) in enumerate(zip(args, expected_data)):
typ = data.typ
if isinstance(typ, ByteArrayType):
pack_args_by_32(holder=holder,
maxlen=maxlen,
arg=arg,
typ=typ,
context=context,
placeholder=placeholder_map[i],
datamem_start=datamem_start,
dynamic_offset_counter=dynamic_offset_counter,
zero_pad_i=zero_pad_i,
pos=pos)
return holder, maxlen, dynamic_offset_counter, datamem_start
def pack_args_by_32(holder,
maxlen,
arg,
typ,
context,
placeholder,
dynamic_offset_counter=None,
datamem_start=None,
zero_pad_i=None,
pos=None):
"""
Copy necessary variables to pre-allocated memory section.
:param holder: Complete holder for all args
:param maxlen: Total length in bytes of the full arg section (static + dynamic).
:param arg: Current arg to pack
:param context: Context of arg
:param placeholder: Static placeholder for static argument part.
:param dynamic_offset_counter: position counter stored in static args.
:param dynamic_placeholder: pointer to current position in memory to write dynamic values to.
:param datamem_start: position where the whole datemem section starts.
"""
if isinstance(typ, BaseType):
value = parse_expr(arg, context)
value = base_type_conversion(value, value.typ, typ, pos)
holder.append(
LLLnode.from_list(['mstore', placeholder, value],
typ=typ,
location='memory'))
elif isinstance(typ, ByteArrayType):
bytez = b''
source_expr = Expr(arg, context)
if isinstance(arg, ast.Str):
if len(arg.s) > typ.maxlen:
raise TypeMismatchException(
"Data input bytes are to big: %r %r" % (len(arg.s), typ),
pos)
for c in arg.s:
if ord(c) >= 256:
raise InvalidLiteralException(
"Cannot insert special character %r into byte array" %
c, pos)
bytez += bytes([ord(c)])
holder.append(source_expr.lll_node)
# Set static offset, in arg slot.
holder.append(
LLLnode.from_list(
['mstore', placeholder, ['mload', dynamic_offset_counter]]))
# Get the biginning to write the ByteArray to.
dest_placeholder = LLLnode.from_list(
['add', datamem_start, ['mload', dynamic_offset_counter]],
typ=typ,
location='memory',
annotation="pack_args_by_32:dest_placeholder")
copier = make_byte_array_copier(dest_placeholder,
source_expr.lll_node,
pos=pos)
holder.append(copier)
# Add zero padding.
new_maxlen = ceil32(source_expr.lll_node.typ.maxlen)
holder.append([
'with',
'_bytearray_loc',
dest_placeholder,
[
'seq',
[
'repeat',
zero_pad_i,
['mload', '_bytearray_loc'],
new_maxlen,
[
'seq',
[
'if', ['ge', ['mload', zero_pad_i], new_maxlen],
'break'
], # stay within allocated bounds
[
'mstore8',
[
'add', ['add', '_bytearray_loc', 32],
['mload', zero_pad_i]
], 0
]
]
]
]
])
# Increment offset counter.
increment_counter = LLLnode.from_list([
'mstore', dynamic_offset_counter,
[
'add',
[
'add', ['mload', dynamic_offset_counter],
['ceil32', ['mload', dest_placeholder]]
], 32
]
])
holder.append(increment_counter)
elif isinstance(typ, ListType):
maxlen += (typ.count - 1) * 32
typ = typ.subtype
def check_list_type_match(provided): # Check list types match.
if provided != typ:
raise TypeMismatchException(
"Log list type '%s' does not match provided, expected '%s'"
% (provided, typ))
# List from storage
if isinstance(arg, ast.Attribute) and arg.value.id == 'self':
stor_list = context.globals[arg.attr]
check_list_type_match(stor_list.typ.subtype)
size = stor_list.typ.count
for offset in range(0, size):
arg2 = LLLnode.from_list([
'sload',
['add', ['sha3_32', Expr(arg, context).lll_node], offset]
],
typ=typ)
p_holder = context.new_placeholder(
BaseType(32)) if offset > 0 else placeholder
holder, maxlen = pack_args_by_32(holder,
maxlen,
arg2,
typ,
context,
p_holder,
pos=pos)
# List from variable.
elif isinstance(arg, ast.Name):
size = context.vars[arg.id].size
pos = context.vars[arg.id].pos
check_list_type_match(context.vars[arg.id].typ.subtype)
for i in range(0, size):
offset = 32 * i
arg2 = LLLnode.from_list(pos + offset,
typ=typ,
location='memory')
p_holder = context.new_placeholder(
BaseType(32)) if i > 0 else placeholder
holder, maxlen = pack_args_by_32(holder,
maxlen,
arg2,
typ,
context,
p_holder,
pos=pos)
# is list literal.
else:
holder, maxlen = pack_args_by_32(holder,
maxlen,
arg.elts[0],
typ,
context,
placeholder,
pos=pos)
for j, arg2 in enumerate(arg.elts[1:]):
holder, maxlen = pack_args_by_32(holder,
maxlen,
arg2,
typ,
context,
context.new_placeholder(
BaseType(32)),
pos=pos)
return holder, maxlen
def call_self_private(stmt_expr, context, sig):
# ** Private Call **
# Steps:
# (x) push current local variables
# (x) push arguments
# (x) push jumpdest (callback ptr)
# (x) jump to label
# (x) pop return values
# (x) pop local variables
method_name, expr_args, sig = call_lookup_specs(stmt_expr, context)
pre_init = []
pop_local_vars = []
push_local_vars = []
pop_return_values = []
push_args = []
# Push local variables.
if context.vars:
var_slots = [(v.pos, v.size) for name, v in context.vars.items()]
var_slots.sort(key=lambda x: x[0])
mem_from, mem_to = var_slots[0][
0], var_slots[-1][0] + var_slots[-1][1] * 32
push_local_vars = [['mload', pos]
for pos in range(mem_from, mem_to, 32)]
pop_local_vars = [['mstore', pos, 'pass']
for pos in reversed(range(mem_from, mem_to, 32))]
# Push Arguments
if expr_args:
inargs, inargsize, arg_pos = pack_arguments(sig,
expr_args,
context,
return_placeholder=False,
pos=getpos(stmt_expr))
push_args += [
inargs
] # copy arguments first, to not mess up the push/pop sequencing.
static_arg_count = len(expr_args) * 32
static_pos = arg_pos + static_arg_count
total_arg_size = ceil32(inargsize - 4)
if len(expr_args) * 32 != total_arg_size: # requires dynamic section.
ident = 'push_args_%d_%d_%d' % (sig.method_id, stmt_expr.lineno,
stmt_expr.col_offset)
start_label = ident + '_start'
end_label = ident + '_end'
i_placeholder = context.new_placeholder(BaseType('uint256'))
push_args += [
['mstore', i_placeholder, arg_pos + total_arg_size],
['label', start_label],
[
'if', ['lt', ['mload', i_placeholder], static_pos],
['goto', end_label]
],
[
'if_unchecked',
['ne', ['mload', ['mload', i_placeholder]], 0],
['mload', ['mload', i_placeholder]]
],
[
'mstore', i_placeholder,
['sub', ['mload', i_placeholder], 32]
], # decrease i
['goto', start_label],
['label', end_label]
]
# push static section
push_args += [['mload', pos]
for pos in reversed(range(arg_pos, static_pos, 32))]
# Jump to function label.
jump_to_func = [
['add', ['pc'], 6], # set callback pointer.
['goto', 'priv_{}'.format(sig.method_id)],
['jumpdest'],
]
# Pop return values.
returner = [0]
if sig.output_type:
output_placeholder, returner, output_size = call_make_placeholder(
stmt_expr, context, sig)
if output_size > 0:
dynamic_offsets = []
if isinstance(sig.output_type, (BaseType, ListType)):
pop_return_values = [[
'mstore', ['add', output_placeholder, pos], 'pass'
] for pos in range(0, output_size, 32)]
elif isinstance(sig.output_type, ByteArrayType):
dynamic_offsets = [(0, sig.output_type)]
pop_return_values = [
['pop', 'pass'],
]
elif isinstance(sig.output_type, TupleType):
static_offset = 0
pop_return_values = []
for out_type in sig.output_type.members:
if isinstance(out_type, ByteArrayType):
pop_return_values.append([
'mstore',
['add', output_placeholder, static_offset], 'pass'
])
dynamic_offsets.append(([
'mload',
['add', output_placeholder, static_offset]
], out_type))
else:
pop_return_values.append([
'mstore',
['add', output_placeholder, static_offset], 'pass'
])
static_offset += 32
# append dynamic unpacker.
dyn_idx = 0
for in_memory_offset, out_type in dynamic_offsets:
ident = "%d_%d_arg_%d" % (stmt_expr.lineno,
stmt_expr.col_offset, dyn_idx)
dyn_idx += 1
start_label = 'dyn_unpack_start_' + ident
end_label = 'dyn_unpack_end_' + ident
i_placeholder = context.new_placeholder(
typ=BaseType('uint256'))
begin_pos = ['add', output_placeholder, in_memory_offset]
# loop until length.
o = LLLnode.from_list(
[
'seq_unchecked',
['mstore', begin_pos, 'pass'], # get len
['mstore', i_placeholder, 0],
['label', start_label],
[
'if',
[
'ge', ['mload', i_placeholder],
['ceil32', ['mload', begin_pos]]
], ['goto', end_label]
], # break
[
'mstore',
[
'add', ['add', begin_pos, 32],
['mload', i_placeholder]
], 'pass'
], # pop into correct memory slot.
[
'mstore', i_placeholder,
['add', 32, ['mload', i_placeholder]]
], # increment i
['goto', start_label],
['label', end_label]
],
typ=None,
annotation='dynamic unpacker',
pos=getpos(stmt_expr))
pop_return_values.append(o)
o = LLLnode.from_list(['seq_unchecked'] + pre_init + push_local_vars +
push_args + jump_to_func + pop_return_values +
pop_local_vars + [returner],
typ=sig.output_type,
location='memory',
pos=getpos(stmt_expr),
annotation='Internal Call: %s' % method_name,
add_gas_estimate=sig.gas)
o.gas += sig.gas
return o