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Shared: Refactor the shared BasicBlock lib slightly and cache the successor relation.

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This commit is contained in:
Anders Schack-Mulligen
2025-05-16 11:31:40 +02:00
parent f202586f5e
commit 13c5906e7e
1 changed files with 20 additions and 17 deletions
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37
shared/controlflow/codeql/controlflow/BasicBlock.qll
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@@ -51,16 +51,6 @@ signature module InputSig<LocationSig Location> {
module Make<LocationSig Location, InputSig<Location> Input> {
private import Input
private Node nodeGetAPredecessor(Node node, SuccessorType s) {
nodeGetASuccessor(result, s) = node
}
/** Holds if this node has more than one predecessor. */
private predicate nodeIsJoin(Node node) { strictcount(nodeGetAPredecessor(node, _)) > 1 }
/** Holds if this node has more than one successor. */
private predicate nodeIsBranch(Node node) { strictcount(nodeGetASuccessor(node, _)) > 1 }
/**
* A basic block, that is, a maximal straight-line sequence of control flow nodes
* without branches or joins.
@@ -76,9 +66,7 @@ module Make<LocationSig Location, InputSig<Location> Input> {
BasicBlock getASuccessor() { result = this.getASuccessor(_) }
/** Gets an immediate successor of this basic block of a given type, if any. */
BasicBlock getASuccessor(SuccessorType t) {
result.getFirstNode() = nodeGetASuccessor(this.getLastNode(), t)
}
BasicBlock getASuccessor(SuccessorType t) { bbSuccessor(this, result, t) }
/** Gets an immediate predecessor of this basic block, if any. */
BasicBlock getAPredecessor() { result.getASuccessor(_) = this }
@@ -287,6 +275,16 @@ module Make<LocationSig Location, InputSig<Location> Input> {
cached
private module Cached {
private Node nodeGetAPredecessor(Node node, SuccessorType s) {
nodeGetASuccessor(result, s) = node
}
/** Holds if this node has more than one predecessor. */
private predicate nodeIsJoin(Node node) { strictcount(nodeGetAPredecessor(node, _)) > 1 }
/** Holds if this node has more than one successor. */
private predicate nodeIsBranch(Node node) { strictcount(nodeGetASuccessor(node, _)) > 1 }
/**
* Internal representation of basic blocks. A basic block is represented
* by its first CFG node.
@@ -343,11 +341,19 @@ module Make<LocationSig Location, InputSig<Location> Input> {
cached
Node getNode(BasicBlock bb, int pos) { bbIndex(bb.getFirstNode(), result, pos) }
/** Holds if `bb` is an entry basic block. */
private predicate entryBB(BasicBlock bb) { nodeIsDominanceEntry(bb.getFirstNode()) }
cached
predicate bbSuccessor(BasicBlock bb1, BasicBlock bb2, SuccessorType t) {
bb2.getFirstNode() = nodeGetASuccessor(bb1.getLastNode(), t)
}
/**
* Holds if the first node of basic block `succ` is a control flow
* successor of the last node of basic block `pred`.
*/
private predicate succBB(BasicBlock pred, BasicBlock succ) { pred.getASuccessor(_) = succ }
private predicate succBB(BasicBlock pred, BasicBlock succ) { bbSuccessor(pred, succ, _) }
/** Holds if `dom` is an immediate dominator of `bb`. */
cached
@@ -367,7 +373,4 @@ module Make<LocationSig Location, InputSig<Location> Input> {
}
private import Cached
/** Holds if `bb` is an entry basic block. */
private predicate entryBB(BasicBlock bb) { nodeIsDominanceEntry(bb.getFirstNode()) }
}