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C++: Speed up primitive basic block calculation #285

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Merged
merged 2 commits into from
Oct 6, 2018
Merged

C++: Speed up primitive basic block calculation #285

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2658520
C++: Faster implementation of BB entry node
jbj Oct 5, 2018
11e03b3
C++: Fix primitive_basic_block_member join order
jbj Oct 5, 2018
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17 changes: 13 additions & 4 deletions cpp/ql/src/semmle/code/cpp/controlflow/internal/PrimitiveBasicBlocks.qll
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Original file line number Diff line number Diff line change
Expand Up @@ -31,8 +31,11 @@ private cached module Cached {
// or the node's predecessor has more than one successor,
// then the node is the start of a new primitive basic block.
or
strictcount (Node pred, Node other
| successors_extended(pred,node) and successors_extended(pred,other)) > 1
strictcount(Node pred | successors_extended(pred, node)) > 1
or
exists(ControlFlowNode pred | successors_extended(pred, node) |
strictcount(ControlFlowNode other | successors_extended(pred, other)) > 1
)

// If the node has zero predecessors then it is the start of
// a BB. However, the C++ AST contains many nodes with zero
Expand Down Expand Up @@ -63,8 +66,14 @@ private cached module Cached {
/** Holds if `node` is the `pos`th control-flow node in primitive basic block `bb`. */
cached
predicate primitive_basic_block_member(Node node, PrimitiveBasicBlock bb, int pos) {
pos = getMemberIndex(node) and
member_step*(bb, node)
primitive_basic_block_entry_node(bb) and
(
pos = 0 and
node = bb
or
pos = getMemberIndex(node) and
member_step+(bb, node)
)
}

/** Gets the number of control-flow nodes in the primitive basic block `bb`. */
Expand Down