angr.analyses.decompiler.optimization_passes.code_motion

class angr.analyses.decompiler.optimization_passes.code_motion.CodeMotionOptimization

Bases: OptimizationPass

Moves common statements out of blocks that share the same predecessors or the same successors. This is done to reduce the number of statements in a block and to make the blocks more similar to each other.

As an example:

if (x) {
    b = 2;
    a = 1;
    c = 3;
} else {
    b = 2;
    c = 3;
}

Will be turned into:

if (x) {
    a = 1;
}
b = 2;
c = 3;

Current limitations (for very conservative operations):

  • moving statements above conditional jumps is not supported

  • only immediate children and parents are considered for moving statements

  • when moving statements down, a block is only considered if already has a matching statement at the end

ARCHES = None
PLATFORMS = None
NAME = 'Merge common statements in sub-scopes'
STAGE: OptimizationPassStage = 6
DESCRIPTION = '\n    Moves common statements out of blocks that share the same predecessors or the same\n    successors. This is done to reduce the number of statements in a block and to make the\n    blocks more similar to each other.\n\n    As an example::\n\n        if (x) {\n            b = 2;\n            a = 1;\n            c = 3;\n        } else {\n            b = 2;\n            c = 3;\n        }\n\n    Will be turned into::\n\n        if (x) {\n            a = 1;\n        }\n        b = 2;\n        c = 3;\n\n    Current limitations (for very conservative operations):\n\n    - moving statements above conditional jumps is not supported\n    - only immediate children and parents are considered for moving statements\n    - when moving statements down, a block is only considered if already has a matching statement at the end\n    '
__init__(*args, max_iters=10, node_idx_start=0, **kwargs)
Parameters:

node_idx_start (int)

static update_graph_with_super_edits(original_graph, super_graph, updated_blocks)

This function updates an graph when doing block edits on a supergraph version of that same graph. The updated blocks must be provided as a dictionary where the keys are original block in the supergraph and the values are the new blocks that should replace them.

The supergraph MUST be generated using the to_ail_supergraph function, since it stores the original nodes each super node represents. This is necessary to update the original graph with the new super nodes.

Return type:

bool

Parameters:

  • original_graph (DiGraph)

  • super_graph (DiGraph)

  • updated_blocks (dict[Block, Block])