def init_declarator(tokens,
symbol_table,
base_type=CType(''),
storage_class=None):
# : declarator ('=' assignment_expression or initializer)?
decl = set_core_type(
symbol_table['__ declarator __'](tokens, symbol_table), base_type)
if peek_or_terminal(tokens) == TOKENS.EQUAL and consume(tokens):
decl = Definition(name(decl), c_type(decl),
EmptyExpression(c_type(decl)), loc(decl),
storage_class)
symbol_table[name(
decl
)] = decl # we have to add it to the symbol table for things like `int a = a;`
expr = initializer_or_assignment_expression(tokens, symbol_table)
# if declaration is an array type and the expression is of string_type then convert to initializer for parsing
if isinstance(c_type(decl), ArrayType) and isinstance(
c_type(expr), StringType):
expr = Initializer(
enumerate(exp(expr)),
ArrayType(c_type(c_type(expr)), len(c_type(expr)), loc(expr)),
loc(expr))
decl.initialization = parse_initializer(expr, decl) if isinstance(
expr, Initializer) else expr
else:
symbol_table[name(decl)] = decl = Declaration(name(decl), c_type(decl),
loc(decl))
return decl
def definition(dec, symbol_table): # Global definition.
assert not isinstance(c_type(dec), FunctionType)
symbol_table[name(dec)] = bind_load_instructions(dec)
symbol_table[name(dec)].symbol = Data( # Add reference of symbol to definition to keep track of references
# static binaries, (packed binaries since machine may require alignment ...)
name(dec), static_def_binaries(dec), size(c_type(dec)), dec.storage_class, loc(dec),
)
return symbol_table[name(dec)].symbol
def declaration(stmnt, symbol_table):
# This are non-global declarations they don't require any space
# but they could be referenced (extern, or function type)
symbol_type = Code if isinstance(c_type(stmnt), FunctionType) else Data
stmnt.symbol = symbol_type(declarations.name(stmnt), (), None, stmnt.storage_class, loc(stmnt))
stmnt.symbol.size = size(c_type(stmnt), overrides={FunctionType: None})
symbol_table[declarations.name(stmnt)] = stmnt
yield Pass(loc(stmnt))
def get_declaration_or_definition(decl, storage_class):
_ = initialization(decl) and isinstance(storage_class, Extern) and raise_error(
'{l} {ident} has both initialization expr and extern storage class'.format(l=loc(decl), ident=name(decl)))
if isinstance(c_type(decl), (FunctionType, StructType)) and not name(decl) or isinstance(storage_class, Extern):
return Declaration(name(decl), c_type(decl), loc(decl), storage_class)
return Definition(name(decl), c_type(decl), initialization(decl), loc(decl), storage_class or Auto(loc(decl)))
def function_definition(dec, symbol_table):
"""
Function Call Convention:
Allocate enough space on the stack for the return type.
Push a new Frame (saves (base & stack ptr))
Push all parameters on the stack from right to left. (The values won't be pop but referenced on stack (+) ...)
Calculate & Push pointer where to return value.
Push pointer where to store return value.
Push the return Address so the callee knows where to return to.
(Reset Base pointer) creating a new Frame.
Jump to callee code segment
callee references values passed on the stack by pushing the base_stack_pointer,
(+offsets) for previous frame and (-offset) for current frame ...
Callee will place the return value in the specified pointer.
Caller Pops frame, and uses the set (returned) value.
"""
symbol = Code(name(dec), None, None, dec.storage_class, loc(dec))
symbol_table[name(dec)] = bind_load_instructions(dec) # bind load/reference instructions, add to symbol table.
symbol_table[name(dec)].symbol = symbol
def binaries(body, symbol_table):
symbol_table = push(symbol_table)
symbol_table['__ stack __'] = Stack() # Each function call has its own Frame which is nothing more than a stack
# Skip return address ...
offset = size_arrays_as_pointers(void_pointer_type) + (
# if function has zero return size then the return pointer will be omitted ...
size_arrays_as_pointers(void_pointer_type) *
bool(size_arrays_as_pointers(c_type(c_type(dec)), overrides={VoidType: 0}))
)
for parameter in c_type(dec):
# monkey patch declarator objects add Load commands according to stack state; add to symbol table.
symbol_table[name(parameter)] = bind_instructions(parameter, offset)
assert not type(parameter) is ArrayType # TODO: fix this.
offset += size_arrays_as_pointers(c_type(parameter))
symbol_table.update(
izip(('__ CURRENT FUNCTION __', '__ LABELS __', '__ GOTOS __'), (dec, SymbolTable(), defaultdict(list)))
)
def pop_symbol_table(symbol_table, location=loc(dec)): # pop symbol table once all binaries have being emitted
yield (pop(symbol_table) or 1) and Pass(location)
return chain( # body of function ...
chain.from_iterable(imap(symbol_table['__ statement __'], chain.from_iterable(body), repeat(symbol_table))),
return_instrs(loc(dec)), # default return instructions, in case one was not giving ...
pop_symbol_table(symbol_table) # pop symbol_table once complete ...
)
symbol.binaries = binaries(initialization(dec), symbol_table)
return symbol
def get_declaration_or_definition(decl, storage_class):
_ = initialization(decl) and isinstance(
storage_class, Extern) and raise_error(
'{l} {ident} has both initialization expr and extern storage class'
.format(l=loc(decl), ident=name(decl)))
if isinstance(c_type(decl),
(FunctionType, StructType)) and not name(decl) or isinstance(
storage_class, Extern):
return Declaration(name(decl), c_type(decl), loc(decl), storage_class)
return Definition(name(decl), c_type(decl), initialization(decl),
loc(decl), storage_class or Auto(loc(decl)))
def definition(dec, symbol_table): # Global definition.
assert not isinstance(c_type(dec), FunctionType)
symbol_table[name(dec)] = bind_load_instructions(dec)
symbol_table[name(
dec
)].symbol = Data( # Add reference of symbol to definition to keep track of references
# static binaries, (packed binaries since machine may require alignment ...)
name(dec),
static_def_binaries(dec),
size(c_type(dec)),
dec.storage_class,
loc(dec),
)
return symbol_table[name(dec)].symbol
def declarations(tokens, symbol_table):
# storage_class_specifier? type_name? init_declarator_list (';' or compound_statement) # declaration
storage_class_specifier, specifier_qualifier_list, statement = imap(
symbol_table.__getitem__,
('__ storage_class_specifier __', '__ specifier_qualifier_list __',
'__ statement __'))
storage_class = storage_class_specifier(tokens, symbol_table)
base_type = specifier_qualifier_list(tokens, symbol_table)
expecting_token = TOKENS.SEMICOLON
if peek_or_terminal(tokens) == TOKENS.SEMICOLON:
yield EmptyDeclaration(loc(consume(tokens)), storage_class)
elif peek_or_terminal(tokens) is terminal:
raise_error(
'{l} Expected TOKENS.COMMA TOKENS.EQUAL TOKENS.SEMICOLON TOKENS.LEFT_BRACE got `{got}`'
.format(l=loc(peek(tokens, EOFLocation)), got=peek(tokens, '')))
else:
for dec in init_declarator_list(tokens,
symbol_table,
base_type=base_type,
storage_class=storage_class):
dec.storage_class = storage_class
if isinstance(
storage_class, TypeDef
): # init_declarator_list adds the symbol as a decl to symbol_table
symbol_table[name(dec)] = (symbol_table.pop(
name(dec)) or 1) and c_type(dec) # replace dec by ctype
elif peek_or_terminal(
tokens) == TOKENS.LEFT_BRACE and not error_if_not_type(
c_type(dec), FunctionType):
symbol_table = push(symbol_table)
symbol_table.update(
chain(
imap(
lambda a: (
name(a), a
), # add non variable list parameters to the symbol table ...
ifilterfalse(
lambda c: isinstance(c_type(c), VAListType),
c_type(dec))),
(('__ RETURN_TYPE __', c_type(c_type(dec))),
('__ LABELS __', SymbolTable()))))
yield FunctionDefinition(dec,
next(statement(tokens, symbol_table)))
expecting_token = (pop(symbol_table) or 1) and ''
else:
yield dec
expecting_token = TOKENS.SEMICOLON
_ = expecting_token and error_if_not_value(tokens, expecting_token)
def label_statement(stmnt, symbol_table):
instr = Pass(loc(stmnt))
labels, gotos, stack, statement = imap(
symbol_table.__getitem__, ('__ LABELS __', '__ GOTOS __', '__ stack __', '__ statement __')
)
labels[name(stmnt)] = (instr, symbol_table['__ stack __'].stack_pointer)
# update all previous gotos referring to this lbl
for alloc_instr, rel_jump_instr, goto_stack_pointer in gotos[name(stmnt)]:
# TODO: bug! set_address uses obj.address.
alloc_instr[0].obj.address = alloc_instr.address + (stack.stack_pointer - goto_stack_pointer)
rel_jump_instr[0].obj = instr
del gotos[name(stmnt)][:]
return chain((instr,), statement(stmnt.statement, symbol_table))
def binaries(body, symbol_table):
symbol_table = push(symbol_table)
symbol_table['__ stack __'] = Stack() # Each function call has its own Frame which is nothing more than a stack
# Skip return address ...
offset = size_arrays_as_pointers(void_pointer_type) + (
# if function has zero return size then the return pointer will be omitted ...
size_arrays_as_pointers(void_pointer_type) *
bool(size_arrays_as_pointers(c_type(c_type(dec)), overrides={VoidType: 0}))
)
for parameter in c_type(dec):
# monkey patch declarator objects add Load commands according to stack state; add to symbol table.
symbol_table[name(parameter)] = bind_instructions(parameter, offset)
assert not type(parameter) is ArrayType # TODO: fix this.
offset += size_arrays_as_pointers(c_type(parameter))
symbol_table.update(
izip(('__ CURRENT FUNCTION __', '__ LABELS __', '__ GOTOS __'), (dec, SymbolTable(), defaultdict(list)))
)
def pop_symbol_table(symbol_table, location=loc(dec)): # pop symbol table once all binaries have being emitted
yield (pop(symbol_table) or 1) and Pass(location)
return chain( # body of function ...
chain.from_iterable(imap(symbol_table['__ statement __'], chain.from_iterable(body), repeat(symbol_table))),
return_instrs(loc(dec)), # default return instructions, in case one was not giving ...
pop_symbol_table(symbol_table) # pop symbol_table once complete ...
)
def composite_specifier(
tokens,
symbol_table,
obj_type=StructType,
member_parse_func=parse_struct_members,
terminal=object()
):
"""
: 'composite type' IDENTIFIER
| 'composite type' IDENTIFIER '{' members '}'
| 'composite type' '{' members '}'
"""
location = loc(consume(tokens))
if peek_or_terminal(tokens) == TOKENS.LEFT_BRACE: # anonymous composite ...
return obj_type(None, member_parse_func(tokens, symbol_table), location)
if isinstance(peek_or_terminal(tokens), IDENTIFIER):
obj = symbol_table.get(obj_type.get_name(peek(tokens)), obj_type(consume(tokens), None, location))
# some composites are bit tricky such as Struct/Union ...
# since any of its members may contain itself as a reference, so we'll add the type to
# the symbol table before adding the members ...
# TODO: make types immutable, right now they are being shared.
if symbol_table.get(obj.name, terminal) is terminal:
symbol_table[name(obj)] = obj
if peek_or_terminal(tokens) == TOKENS.LEFT_BRACE:
obj.members = member_parse_func(tokens, symbol_table)
return obj
raise ValueError('{l} Expected IDENTIFIER or LEFT_BRACE got {got}'.format(
l=loc(peek(tokens, EOFLocation)), got=peek(tokens, '')
))
def init_declarator(tokens, symbol_table, base_type=CType(''), storage_class=None):
# : declarator ('=' assignment_expression or initializer)?
decl = set_core_type(symbol_table['__ declarator __'](tokens, symbol_table), base_type)
if peek_or_terminal(tokens) == TOKENS.EQUAL and consume(tokens):
decl = Definition(name(decl), c_type(decl), EmptyExpression(c_type(decl)), loc(decl), storage_class)
symbol_table[name(decl)] = decl # we have to add it to the symbol table for things like `int a = a;`
expr = initializer_or_assignment_expression(tokens, symbol_table)
# if declaration is an array type and the expression is of string_type then convert to initializer for parsing
if isinstance(c_type(decl), ArrayType) and isinstance(c_type(expr), StringType):
expr = Initializer(
enumerate(exp(expr)), ArrayType(c_type(c_type(expr)), len(c_type(expr)), loc(expr)), loc(expr)
)
decl.initialization = parse_initializer(expr, decl) if isinstance(expr, Initializer) else expr
else:
symbol_table[name(decl)] = decl = Declaration(name(decl), c_type(decl), loc(decl))
return decl
def composite_specifier(tokens,
symbol_table,
obj_type=StructType,
member_parse_func=parse_struct_members,
terminal=object()):
"""
: 'composite type' IDENTIFIER
| 'composite type' IDENTIFIER '{' members '}'
| 'composite type' '{' members '}'
"""
location = loc(consume(tokens))
if peek_or_terminal(
tokens) == TOKENS.LEFT_BRACE: # anonymous composite ...
return obj_type(None, member_parse_func(tokens, symbol_table),
location)
if isinstance(peek_or_terminal(tokens), IDENTIFIER):
obj = symbol_table.get(obj_type.get_name(peek(tokens)),
obj_type(consume(tokens), None, location))
# some composites are bit tricky such as Struct/Union ...
# since any of its members may contain itself as a reference, so we'll add the type to
# the symbol table before adding the members ...
# TODO: make types immutable, right now they are being shared.
if symbol_table.get(obj.name, terminal) is terminal:
symbol_table[name(obj)] = obj
if peek_or_terminal(tokens) == TOKENS.LEFT_BRACE:
obj.members = member_parse_func(tokens, symbol_table)
return obj
raise ValueError('{l} Expected IDENTIFIER or LEFT_BRACE got {got}'.format(
l=loc(peek(tokens, EOFLocation)), got=peek(tokens, '')))
def __init__(self, c_decl, body):
_ = error_if_not_type(c_type(c_decl), FunctionType)
if not all(isinstance(arg, Declarator) for arg in c_type(c_decl)):
raise ValueError('{l} FunctionDef must have concrete declarators as params'.format(l=loc(c_type(c_decl))))
if not isinstance(body, CompoundStatement):
raise ValueError('{l} FunctionDef body is not a compound statement, got {g}'.format(l=loc(c_decl), g=body))
super(FunctionDefinition, self).__init__(name(c_decl), c_type(c_decl), body, loc(c_decl), c_decl.storage_class)
def parse_struct_members(tokens, symbol_table):
declarator = symbol_table['__ declarator __']
location, members = loc(consume(tokens)), OrderedDict()
while peek(tokens, TOKENS.RIGHT_BRACE) != TOKENS.RIGHT_BRACE:
type_spec = specifier_qualifier_list(tokens, symbol_table)
while peek(tokens, TOKENS.SEMICOLON) != TOKENS.SEMICOLON:
decl = declarator(tokens, symbol_table)
set_core_type(decl, type_spec)
if name(decl) in members:
raise ValueError('{l} Duplicate struct member {name} previous at {at}'.format(
l=loc(decl), name=name(decl), at=loc(members[name(decl)])
))
members[name(decl)] = decl
_ = peek_or_terminal(tokens) != TOKENS.SEMICOLON and error_if_not_value(tokens, TOKENS.COMMA)
_ = error_if_not_value(tokens, TOKENS.SEMICOLON)
_ = error_if_not_value(tokens, TOKENS.RIGHT_BRACE)
return members
def identifier_expression(expr, symbol_table):
# Defaults to Load, assignment expression will update it to set.
dec = symbol_table[name(expr)]
if isinstance(
c_type(dec),
(FunctionType,
ArrayType)): # Function/Array Types are nothing more than addresses.
return dec.load_address(loc(expr))
return load(dec.load_address(loc(expr)),
size_arrays_as_pointers(c_type(expr)), loc(expr))
def convert_declaration_to_definition(decl):
_ = isinstance(decl, FunctionDefinition) and raise_error(
'{l} Nested function definitions are not allowed.'.format(l=loc(decl)))
# Non Function declaration without storage class is set to auto
if type(decl) is Declaration and not isinstance(
c_type(decl), FunctionType) and decl.storage_class is not Extern:
decl = Definition( # all non-function-declarations within compound statements are definitions ...
name(decl), c_type(decl), EmptyExpression(c_type(decl), loc(decl)),
loc(decl), decl.storage_class or Auto(loc(decl)))
return decl
def static_definition(stmnt, symbol_table):
def load_address(self, location):
return push(Address(self._initial_data, location), location)
data = static_def_binaries(stmnt, (Pass(loc(stmnt)),))
stmnt._initial_data = peek(data)
stmnt.end_of_data = Pass(loc(stmnt))
stmnt.load_address = bind_load_address_func(load_address, stmnt)
symbol_table[declarations.name(stmnt)] = stmnt
return chain( # jump over embedded data ...
relative_jump(Offset(stmnt.end_of_data, loc(stmnt)), loc(stmnt)), consume_all(data), (stmnt.end_of_data,)
)
def parse_struct_members(tokens, symbol_table):
declarator = symbol_table['__ declarator __']
location, members = loc(consume(tokens)), OrderedDict()
while peek(tokens, TOKENS.RIGHT_BRACE) != TOKENS.RIGHT_BRACE:
type_spec = specifier_qualifier_list(tokens, symbol_table)
while peek(tokens, TOKENS.SEMICOLON) != TOKENS.SEMICOLON:
decl = declarator(tokens, symbol_table)
set_core_type(decl, type_spec)
if name(decl) in members:
raise ValueError(
'{l} Duplicate struct member {name} previous at {at}'.
format(l=loc(decl),
name=name(decl),
at=loc(members[name(decl)])))
members[name(decl)] = decl
_ = peek_or_terminal(
tokens) != TOKENS.SEMICOLON and error_if_not_value(
tokens, TOKENS.COMMA)
_ = error_if_not_value(tokens, TOKENS.SEMICOLON)
_ = error_if_not_value(tokens, TOKENS.RIGHT_BRACE)
return members
def __init__(self, c_decl, body):
_ = error_if_not_type(c_type(c_decl), FunctionType)
if not all(isinstance(arg, Declarator) for arg in c_type(c_decl)):
raise ValueError(
'{l} FunctionDef must have concrete declarators as params'.
format(l=loc(c_type(c_decl))))
if not isinstance(body, CompoundStatement):
raise ValueError(
'{l} FunctionDef body is not a compound statement, got {g}'.
format(l=loc(c_decl), g=body))
super(FunctionDefinition,
self).__init__(name(c_decl), c_type(c_decl), body, loc(c_decl),
c_decl.storage_class)
def convert_declaration_to_definition(decl):
_ = isinstance(decl, FunctionDefinition) and raise_error(
'{l} Nested function definitions are not allowed.'.format(l=loc(decl)))
# Non Function declaration without storage class is set to auto
if type(decl) is Declaration and not isinstance(c_type(decl), FunctionType) and decl.storage_class is not Extern:
decl = Definition( # all non-function-declarations within compound statements are definitions ...
name(decl),
c_type(decl),
EmptyExpression(c_type(decl), loc(decl)),
loc(decl),
decl.storage_class or Auto(loc(decl))
)
return decl
def declarations(tokens, symbol_table):
# storage_class_specifier? type_name? init_declarator_list (';' or compound_statement) # declaration
storage_class_specifier, specifier_qualifier_list, statement = imap(
symbol_table.__getitem__,
('__ storage_class_specifier __', '__ specifier_qualifier_list __', '__ statement __')
)
storage_class = storage_class_specifier(tokens, symbol_table)
base_type = specifier_qualifier_list(tokens, symbol_table)
expecting_token = TOKENS.SEMICOLON
if peek_or_terminal(tokens) == TOKENS.SEMICOLON:
yield EmptyDeclaration(loc(consume(tokens)), storage_class)
elif peek_or_terminal(tokens) is terminal:
raise_error('{l} Expected TOKENS.COMMA TOKENS.EQUAL TOKENS.SEMICOLON TOKENS.LEFT_BRACE got `{got}`'.format(
l=loc(peek(tokens, EOFLocation)), got=peek(tokens, '')
))
else:
for dec in init_declarator_list(tokens, symbol_table, base_type=base_type, storage_class=storage_class):
dec.storage_class = storage_class
if isinstance(storage_class, TypeDef): # init_declarator_list adds the symbol as a decl to symbol_table
symbol_table[name(dec)] = (symbol_table.pop(name(dec)) or 1) and c_type(dec) # replace dec by ctype
elif peek_or_terminal(tokens) == TOKENS.LEFT_BRACE and not error_if_not_type(c_type(dec), FunctionType):
symbol_table = push(symbol_table)
symbol_table.update(chain(
imap(
lambda a: (name(a), a), # add non variable list parameters to the symbol table ...
ifilterfalse(lambda c: isinstance(c_type(c), VAListType), c_type(dec))
),
(('__ RETURN_TYPE __', c_type(c_type(dec))), ('__ LABELS __', SymbolTable()))
))
yield FunctionDefinition(dec, next(statement(tokens, symbol_table)))
expecting_token = (pop(symbol_table) or 1) and ''
else:
yield dec
expecting_token = TOKENS.SEMICOLON
_ = expecting_token and error_if_not_value(tokens, expecting_token)
def call_function(function_call_expr, symbol_table):
l, expr = loc(function_call_expr), left_exp(function_call_expr)
return chain( # if expression is a simple identifier of function type, no need for AbsoluteJump, use RelativeJump
set_base_stack_pointer(load_stack_pointer(l), l),
relative_jump(Offset(symbol_table[name(expr)].get_address_obj(l).obj, l), l),
) if isinstance(expr, IdentifierExpression) and isinstance(c_type(expr), FunctionType) else absolute_jump(
chain(
symbol_table['__ expression __'](expr, symbol_table), # load callee address
# calculate new base stack pointer excluding the callees address ...
# give the callee a new frame... if we where to reset the base stack ptr before evaluating the left_expr
# we run the risk of failing to properly load function address if it was store as a local function pointer
set_base_stack_pointer(add(load_stack_pointer(l), push(size(void_pointer_type), l), l), l)
),
l
)
def executable(symbols,
symbol_table=None,
entry_point=default_entry_point,
libraries=(),
linker=static):
location = '__SOP__' # Start of Program
symbol_table = SymbolTable() if symbol_table is None else symbol_table
__end__ = Word(0, location)
libs = tuple(imap(Library, libraries))
symbols = chain(
symbols, # add heap pointer(s) ...
(
object_file.Data('__base_heap_ptr__',
(Address(__end__, location), ),
size(void_pointer_type), None, location),
object_file.Data('__heap_ptr__', (Address(__end__, location), ),
size(void_pointer_type), None, location),
))
def declarations(symbol_table):
# iterate over all symbols withing symbol_table that do not have binaries (they should be declarations)
for v in chain.from_iterable(
imap(
set_binaries,
ifilterfalse(lambda s: s.binaries,
symbol_table.itervalues()))):
yield v # emit default binaries for declarations ...
# inject declaration into temp symbol_table to generate entry point function call instructions ...
st = {'__ expression __': expression}
_ = declaration(entry_point, st)
instr_seq = chain(
statement( # call entry point ...
FunctionCallExpression(
IdentifierExpression(name(entry_point),
c_type(entry_point), location), (),
c_type(c_type(entry_point)), location), st),
halt(location), # Halt machine on return ...
chain.from_iterable(
starmap(binaries, izip(symbols, repeat(symbol_table)))),
) # link all foreign symbols and emit binaries for declarations ...
return chain(linker(instr_seq, symbol_table, libs),
declarations(symbol_table), (__end__, ))
def call_function(function_call_expr, symbol_table):
l, expr = loc(function_call_expr), left_exp(function_call_expr)
return chain( # if expression is a simple identifier of function type, no need for AbsoluteJump, use RelativeJump
set_base_stack_pointer(load_stack_pointer(l), l),
relative_jump(
Offset(symbol_table[name(expr)].get_address_obj(l).obj, l), l),
) if isinstance(expr, IdentifierExpression) and isinstance(
c_type(expr), FunctionType
) else absolute_jump(
chain(
symbol_table['__ expression __'](
expr, symbol_table), # load callee address
# calculate new base stack pointer excluding the callees address ...
# give the callee a new frame... if we where to reset the base stack ptr before evaluating the left_expr
# we run the risk of failing to properly load function address if it was store as a local function pointer
set_base_stack_pointer(
add(load_stack_pointer(l), push(size(void_pointer_type), l),
l), l)),
l)
def __setitem__(self, key, value):
# C allows multiple declarations, so long as long they are all consistent, with previous declarations
# AND a single definition.
# possible scenarios
# 1) Giving a declaration, check its consistent with previous declaration or definition if any.
# 2) Giving a definition, check its consistent with previous declaration and its consistent with previous
# declaration if any.
if isinstance(value, Declaration) and key in self: # check declarations/definitions ...
# either function definition, definition or declaration or constant_expression(for enums) ...
# check for consistency.
prev = self[key]
if isinstance(prev, Declaration) and c_type(value) == c_type(prev) and name(value) == name(prev):
# TODO: check storage class, extern vs static declarations/definitions ...
# if previous is declaration pop it and insert new either def or dec
_ = type(prev) is Declaration and self.pop(key) # pop previous declaration otherwise do nothing ...
else:
raise ValueError('{l} inconsistent def/dec with previous at {a}'.format(l=loc(value), a=loc(self[key])))
super(SymbolTable, self).__setitem__(key, value)
def executable(symbols, symbol_table=None, entry_point=default_entry_point, libraries=(), linker=static):
location = '__SOP__' # Start of Program
symbol_table = SymbolTable() if symbol_table is None else symbol_table
__end__ = Word(0, location)
libs = tuple(imap(Library, libraries))
symbols = chain(
symbols, # add heap pointer(s) ...
(
object_file.Data(
'__base_heap_ptr__', (Address(__end__, location),), size(void_pointer_type), None, location
),
object_file.Data(
'__heap_ptr__', (Address(__end__, location),), size(void_pointer_type), None, location
),
)
)
def declarations(symbol_table):
# iterate over all symbols withing symbol_table that do not have binaries (they should be declarations)
for v in chain.from_iterable(imap(set_binaries, ifilterfalse(lambda s: s.binaries, symbol_table.itervalues()))):
yield v # emit default binaries for declarations ...
# inject declaration into temp symbol_table to generate entry point function call instructions ...
st = {'__ expression __': expression}
_ = declaration(entry_point, st)
instr_seq = chain(
statement( # call entry point ...
FunctionCallExpression(
IdentifierExpression(name(entry_point), c_type(entry_point), location),
(),
c_type(c_type(entry_point)),
location
),
st
),
halt(location), # Halt machine on return ...
chain.from_iterable(starmap(binaries, izip(symbols, repeat(symbol_table)))),
) # link all foreign symbols and emit binaries for declarations ...
return chain(linker(instr_seq, symbol_table, libs), declarations(symbol_table), (__end__,))
def binaries(body, symbol_table):
symbol_table = push(symbol_table)
symbol_table['__ stack __'] = Stack(
) # Each function call has its own Frame which is nothing more than a stack
# Skip return address ...
offset = size_arrays_as_pointers(void_pointer_type) + (
# if function has zero return size then the return pointer will be omitted ...
size_arrays_as_pointers(void_pointer_type) * bool(
size_arrays_as_pointers(c_type(c_type(dec)),
overrides={VoidType: 0})))
for parameter in c_type(dec):
# monkey patch declarator objects add Load commands according to stack state; add to symbol table.
symbol_table[name(parameter)] = bind_instructions(
parameter, offset)
assert not type(parameter) is ArrayType # TODO: fix this.
offset += size_arrays_as_pointers(c_type(parameter))
symbol_table.update(
izip(('__ CURRENT FUNCTION __', '__ LABELS __', '__ GOTOS __'),
(dec, SymbolTable(), defaultdict(list))))
def pop_symbol_table(symbol_table, location=loc(
dec)): # pop symbol table once all binaries have being emitted
yield (pop(symbol_table) or 1) and Pass(location)
return chain( # body of function ...
chain.from_iterable(
imap(symbol_table['__ statement __'],
chain.from_iterable(body), repeat(symbol_table))),
return_instrs(
loc(dec)
), # default return instructions, in case one was not giving ...
pop_symbol_table(
symbol_table) # pop symbol_table once complete ...
)
def identifier_expression(expr, symbol_table):
# Defaults to Load, assignment expression will update it to set.
dec = symbol_table[name(expr)]
if isinstance(c_type(dec), (FunctionType, ArrayType)): # Function/Array Types are nothing more than addresses.
return dec.load_address(loc(expr))
return load(dec.load_address(loc(expr)), size_arrays_as_pointers(c_type(expr)), loc(expr))
def function_definition(dec, symbol_table):
"""
Function Call Convention:
Allocate enough space on the stack for the return type.
Push a new Frame (saves (base & stack ptr))
Push all parameters on the stack from right to left. (The values won't be pop but referenced on stack (+) ...)
Calculate & Push pointer where to return value.
Push pointer where to store return value.
Push the return Address so the callee knows where to return to.
(Reset Base pointer) creating a new Frame.
Jump to callee code segment
callee references values passed on the stack by pushing the base_stack_pointer,
(+offsets) for previous frame and (-offset) for current frame ...
Callee will place the return value in the specified pointer.
Caller Pops frame, and uses the set (returned) value.
"""
symbol = Code(name(dec), None, None, dec.storage_class, loc(dec))
symbol_table[name(dec)] = bind_load_instructions(
dec) # bind load/reference instructions, add to symbol table.
symbol_table[name(dec)].symbol = symbol
def binaries(body, symbol_table):
symbol_table = push(symbol_table)
symbol_table['__ stack __'] = Stack(
) # Each function call has its own Frame which is nothing more than a stack
# Skip return address ...
offset = size_arrays_as_pointers(void_pointer_type) + (
# if function has zero return size then the return pointer will be omitted ...
size_arrays_as_pointers(void_pointer_type) * bool(
size_arrays_as_pointers(c_type(c_type(dec)),
overrides={VoidType: 0})))
for parameter in c_type(dec):
# monkey patch declarator objects add Load commands according to stack state; add to symbol table.
symbol_table[name(parameter)] = bind_instructions(
parameter, offset)
assert not type(parameter) is ArrayType # TODO: fix this.
offset += size_arrays_as_pointers(c_type(parameter))
symbol_table.update(
izip(('__ CURRENT FUNCTION __', '__ LABELS __', '__ GOTOS __'),
(dec, SymbolTable(), defaultdict(list))))
def pop_symbol_table(symbol_table, location=loc(
dec)): # pop symbol table once all binaries have being emitted
yield (pop(symbol_table) or 1) and Pass(location)
return chain( # body of function ...
chain.from_iterable(
imap(symbol_table['__ statement __'],
chain.from_iterable(body), repeat(symbol_table))),
return_instrs(
loc(dec)
), # default return instructions, in case one was not giving ...
pop_symbol_table(
symbol_table) # pop symbol_table once complete ...
)
symbol.binaries = binaries(initialization(dec), symbol_table)
return symbol
def declaration(dec, symbol_table):
symbol_table[name(dec)] = bind_load_instructions(dec)
symbol_table[name(dec)].symbol = Code(name(dec), (), None, dec.storage_class, loc(dec)) \
if isinstance(c_type(dec), FunctionType) \
else Data(name(dec), (), size(c_type(dec)), dec.storage_class, loc(dec))
return symbol_table[name(dec)].symbol
def non_static_definition(stmnt, symbol_table):
stmnt = stack_allocation(symbol_table['__ stack __'], stmnt)
symbol_table[declarations.name(stmnt)] = stmnt
return rules(non_static_definition)[type(c_type(stmnt))](stmnt, symbol_table)
def declaration(dec, symbol_table):
symbol_table[name(dec)] = bind_load_instructions(dec)
symbol_table[name(dec)].symbol = Code(name(dec), (), None, dec.storage_class, loc(dec)) \
if isinstance(c_type(dec), FunctionType) \
else Data(name(dec), (), size(c_type(dec)), dec.storage_class, loc(dec))
return symbol_table[name(dec)].symbol
