diff options
Diffstat (limited to 'miasm2/analysis/data_flow.py')
| -rw-r--r-- | miasm2/analysis/data_flow.py | 28 |
1 files changed, 16 insertions, 12 deletions
diff --git a/miasm2/analysis/data_flow.py b/miasm2/analysis/data_flow.py index dc72d06a..2201a088 100644 --- a/miasm2/analysis/data_flow.py +++ b/miasm2/analysis/data_flow.py @@ -900,10 +900,9 @@ class PropagateThroughExprMem(object): for dst, src in out.iteritems(): if dst.is_mem(): write_mem = True - if dst != mem_dst and mem_dst in dst: - dst = dst.replace_expr({mem_dst:mem_src}) - if mem_dst in src: - src = src.replace_expr({mem_dst:mem_src}) + ptr = dst.ptr.replace_expr({mem_dst:mem_src}) + dst = ExprMem(ptr, dst.size) + src = src.replace_expr({mem_dst:mem_src}) out_new[dst] = src if out != out_new: assignblk_modified = True @@ -990,15 +989,15 @@ def check_expr_below_stack(ir_arch_a, expr): return True -def retrieve_stack_accesses(ir_arch_a, ssa): +def retrieve_stack_accesses(ir_arch_a, ircfg): """ Walk the ssa graph and find stack based variables. Return a dictionary linking stack base address to its size/name @ir_arch_a: ira instance - @ssa: SSADiGraph instance + @ircfg: IRCFG instance """ stack_vars = set() - for block in ssa.graph.blocks.itervalues(): + for block in ircfg.blocks.itervalues(): for assignblk in block: for dst, src in assignblk.iteritems(): stack_vars.update(get_stack_accesses(ir_arch_a, dst)) @@ -1064,18 +1063,23 @@ def replace_mem_stack_vars(expr, base_to_info): return expr.visit(lambda expr:fix_stack_vars(expr, base_to_info)) -def replace_stack_vars(ir_arch_a, ssa): +def replace_stack_vars(ir_arch_a, ircfg): """ Try to replace stack based memory accesses by variables. + + Hypothesis: the input ircfg must have all it's accesses to stack explicitly + done through the stack register, ie every aliases on those variables is + resolved. + WARNING: may fail @ir_arch_a: ira instance - @ssa: SSADiGraph instance + @ircfg: IRCFG instance """ - base_to_info = retrieve_stack_accesses(ir_arch_a, ssa) + base_to_info = retrieve_stack_accesses(ir_arch_a, ircfg) modified = False - for block in ssa.graph.blocks.itervalues(): + for block in ircfg.blocks.itervalues(): assignblks = [] for assignblk in block: out = {} @@ -1090,7 +1094,7 @@ def replace_stack_vars(ir_arch_a, ssa): out = AssignBlock(out, assignblk.instr) assignblks.append(out) new_block = IRBlock(block.loc_key, assignblks) - ssa.graph.blocks[block.loc_key] = new_block + ircfg.blocks[block.loc_key] = new_block return modified |