def set_empty_dst_to_next(self, block, ir_blocks):
for index, irblock in enumerate(ir_blocks):
if irblock.dst is not None:
continue
next_loc_key = block.get_next()
if next_loc_key is None:
loc_key = None
if block.lines:
line = block.lines[-1]
if line.offset is not None:
loc_key = self.loc_db.get_or_create_offset_location(
line.offset + line.l)
if loc_key is None:
loc_key = self.loc_db.add_location()
block.add_cst(loc_key, AsmConstraint.c_next)
else:
loc_key = next_loc_key
dst = m2_expr.ExprLoc(loc_key, self.pc.size)
if irblock.assignblks:
instr = irblock.assignblks[-1].instr
else:
instr = None
assignblk = AssignBlock({self.IRDst: dst}, instr)
ir_blocks[index] = IRBlock(irblock.loc_key,
list(irblock.assignblks) + [assignblk])
def gen_loc_key_and_expr(self, size):
"""
Return a loc_key and it's corresponding ExprLoc
@size: size of expression
"""
loc_key = self.loc_db.add_location()
return loc_key, m2_expr.ExprLoc(loc_key, size)
def gen_loc_key_and_expr(self, size):
"""
Return a loc_key and it's corresponding ExprLoc
@size: size of expression
"""
loc_key = self.symbol_pool.gen_loc_key()
return loc_key, m2_expr.ExprLoc(loc_key, size)
def block2assignblks(self, block):
irblocks_list = super(mipsCGen, self).block2assignblks(block)
for irblocks in irblocks_list:
for blk_idx, irblock in enumerate(irblocks):
has_breakflow = any(assignblock.instr.breakflow() for assignblock in irblock)
if not has_breakflow:
continue
irs = []
for assignblock in irblock:
if self.ir_arch.pc not in assignblock:
irs.append(AssignBlock(assignments, assignblock.instr))
continue
assignments = dict(assignblock)
# Add internal branch destination
assignments[self.delay_slot_dst] = assignblock[
self.ir_arch.pc]
assignments[self.delay_slot_set] = m2_expr.ExprInt(1, 32)
# Replace IRDst with next instruction
dst_loc_key = self.ir_arch.get_next_instr(assignblock.instr)
assignments[self.ir_arch.IRDst] = m2_expr.ExprLoc(dst_loc_key, 32)
irs.append(AssignBlock(assignments, assignblock.instr))
irblocks[blk_idx] = IRBlock(irblock.loc_key, irs)
return irblocks_list
def tbnz(arg1, arg2, arg3):
bitmask = m2_expr.ExprInt(1, arg1.size) << arg2
dst = arg3 if arg1 & bitmask else m2_expr.ExprLoc(
ir.get_next_loc_key(instr),
64
)
PC = dst
ir.IRDst = dst
def _gen_graph(self):
"""
Gen irbloc digraph
"""
self._graph = DiGraphIR(self.blocks, self.loc_db)
for lbl, block in self.blocks.iteritems():
assert isinstance(lbl, m2_expr.LocKey)
self._graph.add_node(lbl)
for dst in self.dst_trackback(block):
if dst.is_int():
dst_lbl = self.loc_db.get_or_create_offset_location(int(dst))
dst = m2_expr.ExprLoc(dst_lbl.loc_key, self.pc.size)
if dst.is_loc():
self._graph.add_edge(lbl, dst.loc_key)
def add_irblock(self, irblock):
"""
Add the @irblock to the current IRCFG
@irblock: IRBlock instance
"""
self.blocks[irblock.loc_key] = irblock
self.add_node(irblock.loc_key)
for dst in self.dst_trackback(irblock):
if dst.is_int():
dst_loc_key = self.loc_db.get_or_create_offset_location(int(dst))
dst = m2_expr.ExprLoc(dst_loc_key, irblock.dst.size)
if dst.is_loc():
self.add_uniq_edge(irblock.loc_key, dst.loc_key)
def teq(ir, instr, arg1, arg2):
e = []
loc_except, loc_except_expr = ir.gen_loc_key_and_expr(ir.IRDst.size)
loc_next = ir.get_next_loc_key(instr)
loc_next_expr = m2_expr.ExprLoc(loc_next, ir.IRDst.size)
do_except = []
do_except.append(
m2_expr.ExprAssign(
exception_flags,
m2_expr.ExprInt(EXCEPT_DIV_BY_ZERO, exception_flags.size)))
do_except.append(m2_expr.ExprAssign(ir.IRDst, loc_next_expr))
blk_except = IRBlock(loc_except.index, [AssignBlock(do_except, instr)])
cond = arg1 - arg2
e = []
e.append(
m2_expr.ExprAssign(
ir.IRDst, m2_expr.ExprCond(cond, loc_next_expr, loc_except_expr)))
return e, [blk_except]
def remove_jmp_blocks(self):
"""
Remove irblock with only IRDst set, by linking it's parent destination to
the block destination.
"""
# Find candidates
jmp_blocks = set()
for block in self.blocks.itervalues():
if len(block) != 1:
continue
assignblk = block[0]
if len(assignblk) > 1:
continue
assert set(assignblk.keys()) == set([self.IRDst])
if len(self.graph.successors(block.loc_key)) != 1:
continue
if not assignblk[self.IRDst].is_loc():
continue
dst = assignblk[self.IRDst].loc_key
if dst == block.loc_key:
# Infinite loop block
continue
jmp_blocks.add(block.loc_key)
# Remove them, relink graph
modified = False
for loc_key in jmp_blocks:
block = self.blocks[loc_key]
dst_loc_key = block.dst
parents = self.graph.predecessors(block.loc_key)
for lbl in parents:
parent = self.blocks.get(lbl, None)
if parent is None:
continue
dst = parent.dst
if dst.is_id(block.loc_key):
dst = m2_expr.ExprLoc(dst_loc_key, dst.size)
self.graph.discard_edge(lbl, block.loc_key)
self.graph.discard_edge(block.loc_key, dst_loc_key)
self.graph.add_uniq_edge(lbl, dst_loc_key)
modified = True
elif dst.is_cond():
src1, src2 = dst.src1, dst.src2
if src1.is_id(block.loc_key):
dst = m2_expr.ExprCond(dst.cond, m2_expr.ExprLoc(dst_loc_key, dst.size), dst.src2)
self.graph.discard_edge(lbl, block.loc_key)
self.graph.discard_edge(block.loc_key, dst_loc_key)
self.graph.add_uniq_edge(lbl, dst_loc_key)
modified = True
if src2.is_id(block.loc_key):
dst = m2_expr.ExprCond(dst.cond, dst.src1, m2_expr.ExprLoc(dst_loc_key, dst.size))
self.graph.discard_edge(lbl, block.loc_key)
self.graph.discard_edge(block.loc_key, dst_loc_key)
self.graph.add_uniq_edge(lbl, dst_loc_key)
modified = True
if dst.src1 == dst.src2:
dst = dst.src1
else:
continue
new_parent = parent.set_dst(dst)
self.blocks[parent.loc_key] = new_parent
# Remove unlinked useless nodes
for loc_key in jmp_blocks:
if (len(self.graph.predecessors(loc_key)) == 0 and
len(self.graph.successors(loc_key)) == 0):
self.graph.del_node(loc_key)
del self.blocks[loc_key]
return modified
def blr(arg1):
PC = arg1
ir.IRDst = arg1
LR = m2_expr.ExprLoc(ir.get_next_loc_key(instr), 64)
def b_lt(arg1):
cond = cond2expr['LT']
dst = arg1 if cond else m2_expr.ExprLoc(ir.get_next_loc_key(instr), 64)
PC = dst
ir.IRDst = dst
def b_eq(arg1):
dst = arg1 if zf else m2_expr.ExprLoc(ir.get_next_loc_key(instr), 64)
PC = dst
ir.IRDst = dst
def b_ne(arg1):
dst = m2_expr.ExprLoc(ir.get_next_loc_key(instr), 64) if zf else arg1
PC = dst
ir.IRDst = dst
def cbnz(arg1, arg2):
dst = arg2 if arg1 else m2_expr.ExprLoc(ir.get_next_loc_key(instr), 64)
PC = dst
ir.IRDst = dst
def cbz(arg1, arg2):
dst = m2_expr.ExprLoc(ir.get_next_loc_key(instr), 64) if arg1 else arg2
PC = dst
ir.IRDst = dst