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C++: simplify cpp/guarded-free

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This new form is more declarative by use of the `GuardCondition`. Thanks to the tireless effort of @MathiasVP!
This commit is contained in:
Mario Campos
2024-05-01 10:59:16 -05:00
parent 3195f0c828
commit c480431ec0
1 changed files with 5 additions and 28 deletions
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33
cpp/ql/src/experimental/Best Practices/GuardedFree.ql
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@@ -17,32 +17,9 @@ class FreeCall extends FunctionCall {
FreeCall() { this.getTarget().hasGlobalName("free") }
}
from IfStmt stmt, FreeCall fc, Variable v
from GuardCondition gc, FreeCall fc, Variable v, BasicBlock bb
where
stmt.getThen() = fc.getEnclosingStmt() and
(
stmt.getCondition() = v.getAnAccess() and
fc.getArgument(0) = v.getAnAccess()
or
exists(PointerDereferenceExpr cond, PointerDereferenceExpr arg |
fc.getArgument(0) = arg and
stmt.getCondition() = cond and
cond.getOperand+() = v.getAnAccess() and
arg.getOperand+() = v.getAnAccess()
)
or
exists(ArrayExpr cond, ArrayExpr arg |
fc.getArgument(0) = arg and
stmt.getCondition() = cond and
cond.getArrayBase+() = v.getAnAccess() and
arg.getArrayBase+() = v.getAnAccess()
)
or
exists(NEExpr eq |
fc.getArgument(0) = v.getAnAccess() and
stmt.getCondition() = eq and
eq.getAnOperand() = v.getAnAccess() and
eq.getAnOperand().getValue() = "0"
)
)
select stmt, "unnecessary NULL check before call to $@", fc, "free"
gc.ensuresEq(v.getAnAccess(), 0, bb, false) and
fc.getArgument(0) = v.getAnAccess() and
bb = fc.getEnclosingStmt()
select gc, "unnecessary NULL check before call to $@", fc, "free"