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C++: Support macro flow when the macro generates a child expression o… #306

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Merged
MathiasVP merged 1 commit into from
Dec 8, 2025
Merged

C++: Support macro flow when the macro generates a child expression o… #306

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19 changes: 14 additions & 5 deletions cpp/ql/lib/semmle/code/cpp/macroflow/MacroFlow.qll
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Original file line number Diff line number Diff line change
Expand Up @@ -38,8 +38,10 @@ module MacroFlow {
* based on the given configuration.
*/
module Make<ConfigSig Config> {
private predicate hasChildSink(Expr e) { Config::isSink(e.getAChild*()) }

private predicate rev(MacroInvocation mi) {
Config::isSink(mi.getExpr())
hasChildSink(mi.getExpr())
or
exists(MacroInvocation mi1 | rev(mi1) | mi.getParentInvocation() = mi1)
}
Expand All @@ -61,7 +63,7 @@ module MacroFlow {
private newtype TNode =
TMacroInvocationNode(MacroInvocation mi) { fwd(mi) } or
TExprNode(Expr e) {
Config::isSink(e) and
hasChildSink(e) and
(
exists(MacroInvocation mi |
fwd(mi) and
Expand Down Expand Up @@ -138,7 +140,7 @@ module MacroFlow {
)
}

private predicate isSinkNode(Node n) { Config::isSink(n.(ExprNode).getExpr()) }
private predicate isSinkNode(Node n) { hasChildSink(n.(ExprNode).getExpr()) }

private predicate isSourceNode(Node n) {
isSource(n.(MacroInvocationNode).getMacroInvocation())
Expand All @@ -159,9 +161,16 @@ module MacroFlow {
isSinkNode(n2)
}

predicate flowsTo(Node n, ExprNode n2, Expr e) {
predicate flowsTo(Node n, ExprNode n2, Expr e, boolean exact) {
stepsStar(n, n2) and
n2.getExpr() = e
Config::isSink(e) and
(
n2.getExpr() = e and
exact = true
or
n2.getExpr().getAChild+() = e and
exact = false
)
}

/**
Expand Down