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C#: Avoid recomputation in last data flow stage

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Avoid recomputing the `ControlFlowReachabilityConfiguration` predicates, as well
as `DispatchCall::getStaticTarget()`.
This commit is contained in:
Tom Hvitved
2019-08-19 17:12:56 +02:00
parent d1755500e4
commit 2a2e07d2fc
2 changed files with 50 additions and 48 deletions
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93
csharp/ql/src/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll
View File

@@ -608,6 +608,16 @@ private module ParameterNodes {
}
import ParameterNodes
/** A data flow node that represents a call argument. */
abstract class ArgumentNode extends Node {
/** Holds if this argument occurs at the given position in the given call. */
cached
abstract predicate argumentOf(DataFlowCall call, int pos);
/** Gets the call in which this node is an argument. */
final DataFlowCall getCall() { this.argumentOf(result, _) }
}
private module ArgumentNodes {
class DelegateArgumentConfiguration extends ControlFlowReachabilityConfiguration {
DelegateArgumentConfiguration() { this = "DelegateArgumentConfiguration" }
@@ -625,9 +635,9 @@ private module ArgumentNodes {
}
/**
* Holds if `arg` is an argument of the call `call`, which resolves to a
* library callable that is known to forward `arg` into the `i`th parameter
* of a supplied delegate `delegate`.
* Holds if `arg` is an argument of a call, which resolves to a library callable
* that is known to forward `arg` into the `i`th parameter of a supplied
* delegate `delegate`.
*
* For example, in
*
@@ -638,9 +648,9 @@ private module ArgumentNodes {
* `arg = x`, `i = 0`, `call = x.Select(Foo)`, and `delegate = Foo`.
*/
private predicate flowIntoCallableLibraryCall(
DataFlowCall call, Node arg, ImplicitDelegateDataFlowCall delegate, int i
ExplicitArgumentNode arg, ImplicitDelegateDataFlowCall delegate, int i
) {
exists(int j, boolean preservesValue |
exists(DataFlowCall call, int j, boolean preservesValue |
preservesValue = true and i = j
or
preservesValue = false and i = j + delegate.getNumberOfDelegateParameters()
@@ -678,43 +688,34 @@ private module ArgumentNodes {
}
}
/** A data flow node that represents a call argument. */
abstract class ArgumentNode extends Node {
/** Holds if this argument occurs at the given position in the given call. */
cached
abstract predicate argumentOf(DataFlowCall call, int pos);
/** Gets the call in which this node is an argument. */
final DataFlowCall getCall() { this.argumentOf(result, _) }
}
/** A data flow node that represents an explicit call argument. */
private class ExplicitArgumentNode extends ArgumentNode {
private DataFlowCall c;
private int i;
ExplicitArgumentNode() {
exists(ArgumentConfiguration x, Expr call, Argument arg |
arg = this.asExpr() and
call = c.getExpr() and
arg.isArgumentOf(call, i) and
x.hasExprPath(_, this.getControlFlowNode(), _, c.getControlFlowNode())
)
this.asExpr() instanceof Argument
or
exists(CIL::Call call, CIL::Expr arg |
arg = this.asExpr() and
call = c.getExpr() and
arg = call.getArgument(i)
)
this.asExpr() = any(CIL::Call call).getAnArgument()
or
flowIntoCallableLibraryCall(_, this, c, i)
libraryFlowDelegateCallIn(_, _, this.asExpr(), _, _, _)
or
this.(ImplicitDelegateOutNode).isArgumentOf(_, _)
}
override predicate argumentOf(DataFlowCall call, int pos) {
Stages::DataFlowStage::forceCachingInSameStage() and
call = c and
pos = i
exists(ArgumentConfiguration x, Expr c, Argument arg |
arg = this.asExpr() and
c = call.getExpr() and
arg.isArgumentOf(c, pos) and
x.hasExprPath(_, this.getControlFlowNode(), _, call.getControlFlowNode())
)
or
exists(CIL::Call c, CIL::Expr arg |
arg = this.asExpr() and
c = call.getExpr() and
arg = c.getArgument(pos)
)
or
flowIntoCallableLibraryCall(this, call, pos)
}
}
@@ -849,13 +850,13 @@ private module ArgumentNodes {
}
import ArgumentNodes
private module ReturnNodes {
/** A data flow node that represents a value returned by a callable. */
abstract class ReturnNode extends Node {
/** Gets the kind of this return node. */
abstract ReturnKind getKind();
}
/** A data flow node that represents a value returned by a callable. */
abstract class ReturnNode extends Node {
/** Gets the kind of this return node. */
abstract ReturnKind getKind();
}
private module ReturnNodes {
/**
* A data flow node that represents an expression returned by a callable,
* either using a (`yield`) `return` statement or an expression body (`=>`).
@@ -962,14 +963,14 @@ private module ReturnNodes {
}
import ReturnNodes
private module OutNodes {
/** A data flow node that represents the output of a call. */
abstract class OutNode extends Node {
/** Gets the underlying call. */
cached
abstract DataFlowCall getCall();
}
/** A data flow node that represents the output of a call. */
abstract class OutNode extends Node {
/** Gets the underlying call. */
cached
abstract DataFlowCall getCall();
}
private module OutNodes {
private DataFlowCall csharpCall(Expr e, ControlFlow::Node cfn) {
e = any(DispatchCall dc | result = TNonDelegateCall(cfn, dc)).getCall() or
result = TExplicitDelegateCall(cfn, e)

5
csharp/ql/src/semmle/code/csharp/dispatch/Dispatch.qll
View File

@@ -83,6 +83,9 @@ private module Internal {
cached
Expr getQualifier(DispatchCall dc) { result = dc.(DispatchCallImpl).getQualifier() }
cached
Callable getAStaticTarget(DispatchCall dc) { result = dc.(DispatchCallImpl).getAStaticTarget() }
cached
RuntimeCallable getADynamicTarget(DispatchCall dc) {
result = dc.(DispatchCallImpl).getADynamicTarget()
@@ -90,8 +93,6 @@ private module Internal {
}
import Cached
Callable getAStaticTarget(DispatchCall dc) { result = dc.(DispatchCallImpl).getAStaticTarget() }
/**
* Holds if `mc` is a reflection call to a method named `name`, where
* `object` is the object on which to invoke the method (`null` if a