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C++: Reduce number of SubBasicBlocks in FlowVar

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by cutting basic blocks at the same place for the `x.a` partial
definition in `x.a = ...` as they were already cut for assignment to
`a`.
This commit is contained in:
Jonas Jensen
2019-08-12 15:58:35 +02:00
parent 0507d51f0c
commit 3f531380d1
1 changed files with 11 additions and 10 deletions
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21
cpp/ql/src/semmle/code/cpp/dataflow/internal/FlowVar.qll
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@@ -89,31 +89,34 @@ cached class FlowVar extends TFlowVar {
*/ */
private module PartialDefinitions { private module PartialDefinitions {
private newtype TPartialDefinition = private newtype TPartialDefinition =
TExplicitFieldStoreQualifier(Expr qualifier, FieldAccess fa) { TExplicitFieldStoreQualifier(Expr qualifier, ControlFlowNode node) {
isInstanceFieldWrite(fa) and qualifier = fa.getQualifier() exists(FieldAccess fa |
isInstanceFieldWrite(fa, node) and qualifier = fa.getQualifier()
)
} or } or
TExplicitCallQualifier(Expr qualifier, Call call) { qualifier = call.getQualifier() } or TExplicitCallQualifier(Expr qualifier, Call call) { qualifier = call.getQualifier() } or
TReferenceArgument(Expr arg, VariableAccess va) { definitionByReference(va, arg) } TReferenceArgument(Expr arg, VariableAccess va) { definitionByReference(va, arg) }
private predicate isInstanceFieldWrite(FieldAccess fa) { private predicate isInstanceFieldWrite(FieldAccess fa, ControlFlowNode node) {
not fa.getTarget().isStatic() and not fa.getTarget().isStatic() and
assignmentLikeOperation(_, fa.getTarget(), fa, _) assignmentLikeOperation(node, fa.getTarget(), fa, _)
} }
class PartialDefinition extends TPartialDefinition { class PartialDefinition extends TPartialDefinition {
Expr definedExpr; Expr definedExpr;
ControlFlowNode node;
PartialDefinition() { PartialDefinition() {
this = TExplicitFieldStoreQualifier(definedExpr, _) or this = TExplicitFieldStoreQualifier(definedExpr, node) or
this = TExplicitCallQualifier(definedExpr, _) or this = TExplicitCallQualifier(definedExpr, _) and node = definedExpr or
this = TReferenceArgument(definedExpr, _) this = TReferenceArgument(definedExpr, node)
} }
predicate partiallyDefines(Variable v) { definedExpr = v.getAnAccess() } predicate partiallyDefines(Variable v) { definedExpr = v.getAnAccess() }
predicate partiallyDefinesThis(ThisExpr e) { definedExpr = e } predicate partiallyDefinesThis(ThisExpr e) { definedExpr = e }
ControlFlowNode getSubBasicBlockStart() { result = definedExpr } ControlFlowNode getSubBasicBlockStart() { result = node }
Expr getDefinedExpr() { result = definedExpr } Expr getDefinedExpr() { result = definedExpr }
@@ -141,8 +144,6 @@ private module PartialDefinitions {
VariableAccess getVariableAccess() { result = va } VariableAccess getVariableAccess() { result = va }
override predicate partiallyDefines(Variable v) { va = v.getAnAccess() } override predicate partiallyDefines(Variable v) { va = v.getAnAccess() }
override ControlFlowNode getSubBasicBlockStart() { result = va }
} }
} }
import PartialDefinitions import PartialDefinitions