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GeezerVison is showing github.com — C++: Use the optimized version of getAnUltimateDefinition for iterato… · github/codeql@891f2e1

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  • cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal
    • DataFlowPrivate.qll
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‎cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowPrivate.qll‎

Copy file name to clipboardExpand all lines: cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowPrivate.qll
+41-25Lines changed: 41 additions & 25 deletions
Original file line numberDiff line numberDiff line change
@@ -1977,13 +1977,23 @@ module IteratorFlow {
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}
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/**
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* Gets an ultimate definition of `def`.
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*
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* Note: Unlike `def.getAnUltimateDefinition()` this predicate also
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* traverses back through iterator increment and decrement operations.
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* Holds if `write` is an instruction that writes to address `address`
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*/
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private Ssa::Definition getAnUltimateDefinition(Ssa::Definition def) {
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result = def.getAnUltimateDefinition()
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private predicate isIteratorWrite(Instruction write, Operand address) {
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exists(Ssa::DefImpl writeDef, IRBlock bb, int i |
1984+
writeDef.hasIndexInBlock(_, bb, i) and
1985+
bb.getInstruction(i) = write and
1986+
address = writeDef.getAddressOperand()
1987+
)
1988+
}
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private module GetAnUltimateDefinitionInput implements Ssa::GetAnUltimateDefinitionSig {
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predicate isRelevantUltimateDefinition(Ssa::Definition def) { fwd(_, def) }
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}
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private Ssa::Definition getAnUltimateDefinitionStep(Ssa::Definition def) {
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result =
1996+
Ssa::GetAnUltimateDefinition<GetAnUltimateDefinitionInput>::getAnUltimateDefinition(def)
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or
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exists(IRBlock bb, int i, IteratorCrementCall crementCall, Ssa::SourceVariable sv |
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crementCall = def.getValue().asInstruction().(StoreInstruction).getSourceValue() and
@@ -1993,14 +2003,28 @@ module IteratorFlow {
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)
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}
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/**
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* Holds if `write` is an instruction that writes to address `address`
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*/
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private predicate isIteratorWrite(Instruction write, Operand address) {
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exists(Ssa::DefImpl writeDef, IRBlock bb, int i |
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writeDef.hasIndexInBlock(_, bb, i) and
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bb.getInstruction(i) = write and
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address = writeDef.getAddressOperand()
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private predicate isSource(GetsIteratorCall beginCall, Ssa::Definition def) {
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exists(StoreInstruction beginStore |
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beginStore = def.getValue().asInstruction() and
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operandForFullyConvertedCall(beginStore.getSourceValueOperand(), beginCall)
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)
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}
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private predicate isSink(Instruction writeToDeref, Ssa::Definition def) {
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exists(IteratorPointerDereferenceCall starCall, Operand address, IRBlock bbStar, int iStar |
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isIteratorWrite(writeToDeref, address) and
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operandForFullyConvertedCall(address, starCall) and
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bbStar.getInstruction(iStar) = starCall and
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Ssa::ssaDefReachesRead(_, def, bbStar, iStar)
2019+
)
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}
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private predicate fwd(GetsIteratorCall beginCall, Ssa::Definition def) {
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isSource(beginCall, def)
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or
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exists(Ssa::Definition def0 |
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fwd(beginCall, def0) and
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def0 = getAnUltimateDefinitionStep(def)
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)
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}
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@@ -2016,17 +2040,9 @@ module IteratorFlow {
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private predicate isIteratorStoreInstruction(
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GetsIteratorCall beginCall, Instruction writeToDeref
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) {
2019-
exists(
2020-
StoreInstruction beginStore, IRBlock bbStar, int iStar, Ssa::Definition def,
2021-
IteratorPointerDereferenceCall starCall, Ssa::Definition ultimate, Operand address
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|
2023-
isIteratorWrite(writeToDeref, address) and
2024-
operandForFullyConvertedCall(address, starCall) and
2025-
bbStar.getInstruction(iStar) = starCall and
2026-
Ssa::ssaDefReachesRead(_, def, bbStar, iStar) and
2027-
ultimate = getAnUltimateDefinition*(def) and
2028-
beginStore = ultimate.getValue().asInstruction() and
2029-
operandForFullyConvertedCall(beginStore.getSourceValueOperand(), beginCall)
2043+
exists(Ssa::Definition def |
2044+
fwd(beginCall, def) and
2045+
isSink(writeToDeref, def)
20302046
)
20312047
}
20322048

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