C++: fix escape test failures

Robert Marsh · Robert Marsh · commit a72cd23d1d34 · 2019-03-07T13:14:51.000-08:00
diff --git a/cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/internal/AliasAnalysis.qll b/cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/internal/AliasAnalysis.qll
@@ -71,7 +71,8 @@ predicate operandEscapesDomain(Operand operand) {
   not operandIsConsumedWithoutEscaping(operand) and
   not operandIsPropagated(operand, _) and
   not isArgumentForParameter(_, operand, _) and
-  not isOnlyEscapesViaReturnArgument(operand)
+  not isOnlyEscapesViaReturnArgument(operand) and
+  not operand.getUseInstruction() instanceof ReturnValueInstruction
 }
 
 /**
diff --git a/cpp/ql/src/semmle/code/cpp/ir/implementation/unaliased_ssa/internal/AliasAnalysis.qll b/cpp/ql/src/semmle/code/cpp/ir/implementation/unaliased_ssa/internal/AliasAnalysis.qll
@@ -71,7 +71,8 @@ predicate operandEscapesDomain(Operand operand) {
   not operandIsConsumedWithoutEscaping(operand) and
   not operandIsPropagated(operand, _) and
   not isArgumentForParameter(_, operand, _) and
-  not isOnlyEscapesViaReturnArgument(operand)
+  not isOnlyEscapesViaReturnArgument(operand) and
+  not operand.getUseInstruction() instanceof ReturnValueInstruction
 }
 
 /**
@@ -208,21 +209,21 @@ predicate isArgumentForParameter(CallInstruction ci, Operand operand, Instructio
   )
 }
 
-predicate isAlwaysReturnedArgument(Operand operand) {
+private predicate isAlwaysReturnedArgument(Operand operand) {
   exists(AliasFunction f |
     f = operand.getUseInstruction().(CallInstruction).getStaticCallTarget() and
     f.parameterIsAlwaysReturned(operand.(PositionalArgumentOperand).getIndex())
   )
 }
 
-predicate isOnlyEscapesViaReturnArgument(Operand operand) {
+private predicate isOnlyEscapesViaReturnArgument(Operand operand) {
   exists(AliasFunction f |
     f = operand.getUseInstruction().(CallInstruction).getStaticCallTarget() and
     f.parameterEscapesOnlyViaReturn(operand.(PositionalArgumentOperand).getIndex())
   )
 }
 
-predicate isNeverEscapesArgument(Operand operand) {
+private predicate isNeverEscapesArgument(Operand operand) {
   exists(AliasFunction f |
     f = operand.getUseInstruction().(CallInstruction).getStaticCallTarget() and
     f.parameterNeverEscapes(operand.(PositionalArgumentOperand).getIndex())

Original file line number	Diff line number	Diff line change
`@@ -71,7 +71,8 @@ predicate operandEscapesDomain(Operand operand) {`
`71`	`71`	`not operandIsConsumedWithoutEscaping(operand) and`
`72`	`72`	`not operandIsPropagated(operand, _) and`
`73`	`73`	`not isArgumentForParameter(_, operand, _) and`
`74`		`- not isOnlyEscapesViaReturnArgument(operand)`
	`74`	`+ not isOnlyEscapesViaReturnArgument(operand) and`
	`75`	`+ not operand.getUseInstruction() instanceof ReturnValueInstruction`
`75`	`76`	`}`
`76`	`77`
`77`	`78`	`/**`