Java: Replace SSA wrapper classes with shared implementation.

java/ql/lib/semmle/code/java/controlflow/Guards.qll

@@ -141,7 +141,7 @@ private predicate isNonFallThroughPredecessor(SwitchCase sc, ControlFlowNode pre
 
 private module GuardsInput implements SharedGuards::InputSig<Location, ControlFlowNode, BasicBlock> {
   private import java as J
-  private import semmle.code.java.dataflow.internal.BaseSSA
+  private import semmle.code.java.dataflow.internal.BaseSSA as Base
   private import semmle.code.java.dataflow.NullGuards as NullGuards
 
   class NormalExitNode = ControlFlow::NormalExitNode;
@@ -211,10 +211,10 @@ private module GuardsInput implements SharedGuards::InputSig<Location, ControlFl
         f.getInitializer() = NullGuards::baseNotNullExpr()
       )
       or
-      exists(CatchClause cc, LocalVariableDeclExpr decl, BaseSsaUpdate v |
+      exists(CatchClause cc, LocalVariableDeclExpr decl, Base::SsaExplicitWrite v |
         decl = cc.getVariable() and
         decl = v.getDefiningExpr() and
-        this = v.getAUse()
+        this = v.getARead()
       )
     }
   }
@@ -407,30 +407,8 @@ private module LogicInputCommon {
 }
 
 private module LogicInput_v1 implements GuardsImpl::LogicInputSig {
-  private import semmle.code.java.dataflow.internal.BaseSSA
-
-  final private class FinalBaseSsaVariable = BaseSsaVariable;
-
-  class SsaDefinition extends FinalBaseSsaVariable {
-    GuardsInput::Expr getARead() { result = this.getAUse() }
-  }
-
-  class SsaExplicitWrite extends SsaDefinition instanceof BaseSsaUpdate {
-    GuardsInput::Expr getValue() {
-      super.getDefiningExpr().(VariableAssign).getSource() = result or
-      super.getDefiningExpr().(AssignOp) = result
-    }
-  }
-
-  class SsaPhiDefinition extends SsaDefinition instanceof BaseSsaPhiNode {
-    predicate hasInputFromBlock(SsaDefinition inp, BasicBlock bb) {
-      super.hasInputFromBlock(inp, bb)
-    }
-  }
-
-  class SsaParameterInit extends SsaDefinition instanceof BaseSsaImplicitInit {
-    Parameter getParameter() { super.isParameterDefinition(result) }
-  }
+  private import semmle.code.java.dataflow.internal.BaseSSA as Base
+  import Base::Ssa
 
   predicate additionalNullCheck = LogicInputCommon::additionalNullCheck/4;
 

java/ql/lib/semmle/code/java/dataflow/TypeFlow.qll

@@ -12,7 +12,7 @@ module;
 
 import java as J
 private import semmle.code.java.dispatch.VirtualDispatch
-private import semmle.code.java.dataflow.internal.BaseSSA
+private import semmle.code.java.dataflow.internal.BaseSSA as Base
 private import semmle.code.java.controlflow.Guards
 private import codeql.typeflow.TypeFlow
 private import codeql.typeflow.UniversalFlow as UniversalFlow
@@ -27,7 +27,7 @@ private RefType boxIfNeeded(J::Type t) {
 module FlowStepsInput implements UniversalFlow::UniversalFlowInput<Location> {
   private newtype TFlowNode =
     TField(Field f) { not f.getType() instanceof PrimitiveType } or
-    TSsa(BaseSsaVariable ssa) { not ssa.getSourceVariable().getType() instanceof PrimitiveType } or
+    TSsa(Base::SsaDefinition ssa) { not ssa.getSourceVariable().getType() instanceof PrimitiveType } or
     TExpr(Expr e) or
     TMethod(Method m) { not m.getReturnType() instanceof PrimitiveType }
 
@@ -55,7 +55,7 @@ module FlowStepsInput implements UniversalFlow::UniversalFlowInput<Location> {
     Field asField() { this = TField(result) }
 
     /** Gets the SSA variable corresponding to this node, if any. */
-    BaseSsaVariable asSsa() { this = TSsa(result) }
+    Base::SsaDefinition asSsa() { this = TSsa(result) }
 
     /** Gets the expression corresponding to this node, if any. */
     Expr asExpr() { this = TExpr(result) }
@@ -107,7 +107,7 @@ module FlowStepsInput implements UniversalFlow::UniversalFlowInput<Location> {
       not e.(FieldAccess).getField() = f
     )
     or
-    n2.asSsa().(BaseSsaPhiNode).getAnUltimateLocalDefinition() = n1.asSsa()
+    n2.asSsa().(Base::SsaPhiDefinition).getAnUltimateDefinition() = n1.asSsa()
     or
     exists(ReturnStmt ret |
       n2.asMethod() = ret.getEnclosingCallable() and ret.getResult() = n1.asExpr()
@@ -118,24 +118,24 @@ module FlowStepsInput implements UniversalFlow::UniversalFlowInput<Location> {
     exists(Argument arg, Parameter p |
       privateParamArg(p, arg) and
       n1.asExpr() = arg and
-      n2.asSsa().(BaseSsaImplicitInit).isParameterDefinition(p) and
+      n2.asSsa().(Base::SsaParameterInit).getParameter() = p and
       // skip trivial recursion
-      not arg = n2.asSsa().getAUse()
+      not arg = n2.asSsa().getARead()
     )
     or
     n2.asExpr() = n1.asField().getAnAccess()
     or
-    n2.asExpr() = n1.asSsa().getAUse()
+    n2.asExpr() = n1.asSsa().getARead()
     or
     n2.asExpr().(CastingExpr).getExpr() = n1.asExpr() and
     not n2.asExpr().getType() instanceof PrimitiveType
     or
     n2.asExpr().(AssignExpr).getSource() = n1.asExpr() and
     not n2.asExpr().getType() instanceof PrimitiveType
     or
-    n2.asSsa().(BaseSsaUpdate).getDefiningExpr().(VariableAssign).getSource() = n1.asExpr()
+    n2.asSsa().(Base::SsaExplicitWrite).getDefiningExpr().(VariableAssign).getSource() = n1.asExpr()
     or
-    n2.asSsa().(BaseSsaImplicitInit).captures(n1.asSsa())
+    n2.asSsa().(Base::SsaCapturedDefinition).captures(n1.asSsa())
     or
     n2.asExpr().(NotNullExpr).getExpr() = n1.asExpr()
   }
@@ -147,7 +147,7 @@ module FlowStepsInput implements UniversalFlow::UniversalFlowInput<Location> {
     n.asExpr() instanceof NullLiteral
     or
     exists(LocalVariableDeclExpr decl |
-      n.asSsa().(BaseSsaUpdate).getDefiningExpr() = decl and
+      n.asSsa().(Base::SsaExplicitWrite).getDefiningExpr() = decl and
       not decl.hasImplicitInit() and
       not exists(decl.getInitOrPatternSource())
     )
@@ -216,7 +216,9 @@ private module Input implements TypeFlowInput<Location> {
     )
   }
 
-  private predicate upcastEnhancedForStmtAux(BaseSsaUpdate v, RefType t, RefType t1, RefType t2) {
+  private predicate upcastEnhancedForStmtAux(
+    Base::SsaExplicitWrite v, RefType t, RefType t1, RefType t2
+  ) {
     exists(EnhancedForStmt for |
       for.getVariable() = v.getDefiningExpr() and
       v.getSourceVariable().getType().getErasure() = t2 and
@@ -230,17 +232,17 @@ private module Input implements TypeFlowInput<Location> {
    * the type of the elements being iterated over, and this type is more precise
    * than the type of `v`.
    */
-  private predicate upcastEnhancedForStmt(BaseSsaUpdate v, RefType t) {
+  private predicate upcastEnhancedForStmt(Base::SsaExplicitWrite v, RefType t) {
     exists(RefType t1, RefType t2 |
       upcastEnhancedForStmtAux(v, t, t1, t2) and
       t1.getASourceSupertype+() = t2
     )
   }
 
   private predicate downcastSuccessorAux(
-    CastingExpr cast, BaseSsaVariable v, RefType t, RefType t1, RefType t2
+    CastingExpr cast, Base::SsaDefinition v, RefType t, RefType t1, RefType t2
   ) {
-    cast.getExpr() = v.getAUse() and
+    cast.getExpr() = v.getARead() and
     t = cast.getType() and
     t1 = t.getErasure() and
     t2 = v.getSourceVariable().getType().getErasure()
@@ -250,10 +252,10 @@ private module Input implements TypeFlowInput<Location> {
    * Holds if `va` is an access to a value that has previously been downcast to `t`.
    */
   private predicate downcastSuccessor(VarAccess va, RefType t) {
-    exists(CastingExpr cast, BaseSsaVariable v, RefType t1, RefType t2 |
+    exists(CastingExpr cast, Base::SsaDefinition v, RefType t1, RefType t2 |
       downcastSuccessorAux(pragma[only_bind_into](cast), v, t, t1, t2) and
       t1.getASourceSupertype+() = t2 and
-      va = v.getAUse() and
+      va = v.getARead() and
       dominates(cast.getControlFlowNode(), va.getControlFlowNode()) and
       dominates(cast.getControlFlowNode().getANormalSuccessor(), va.getControlFlowNode())
     )
@@ -263,9 +265,9 @@ private module Input implements TypeFlowInput<Location> {
    * Holds if `va` is an access to a value that is guarded by `instanceof t` or `case e t`.
    */
   private predicate typeTestGuarded(VarAccess va, RefType t) {
-    exists(Guard typeTest, BaseSsaVariable v |
-      typeTest.appliesTypeTest(v.getAUse(), t, _) and
-      va = v.getAUse() and
+    exists(Guard typeTest, Base::SsaDefinition v |
+      typeTest.appliesTypeTest(v.getARead(), t, _) and
+      va = v.getARead() and
       guardControls_v1(typeTest, va.getBasicBlock(), true)
     )
   }
@@ -274,12 +276,12 @@ private module Input implements TypeFlowInput<Location> {
    * Holds if `aa` is an access to a value that is guarded by `instanceof t` or `case e t`.
    */
   private predicate arrayTypeTestGuarded(ArrayAccess aa, RefType t) {
-    exists(Guard typeTest, BaseSsaVariable v1, BaseSsaVariable v2, ArrayAccess aa1 |
+    exists(Guard typeTest, Base::SsaDefinition v1, Base::SsaDefinition v2, ArrayAccess aa1 |
       typeTest.appliesTypeTest(aa1, t, _) and
-      aa1.getArray() = v1.getAUse() and
-      aa1.getIndexExpr() = v2.getAUse() and
-      aa.getArray() = v1.getAUse() and
-      aa.getIndexExpr() = v2.getAUse() and
+      aa1.getArray() = v1.getARead() and
+      aa1.getIndexExpr() = v2.getARead() and
+      aa.getArray() = v1.getARead() and
+      aa.getIndexExpr() = v2.getARead() and
       guardControls_v1(typeTest, aa.getBasicBlock(), true)
     )
   }
@@ -321,14 +323,14 @@ private module Input implements TypeFlowInput<Location> {
    * Holds if `ioe` checks `v`, its true-successor is `bb`, and `bb` has multiple
    * predecessors.
    */
-  private predicate instanceofDisjunct(InstanceOfExpr ioe, BasicBlock bb, BaseSsaVariable v) {
-    ioe.getExpr() = v.getAUse() and
+  private predicate instanceofDisjunct(InstanceOfExpr ioe, BasicBlock bb, Base::SsaDefinition v) {
+    ioe.getExpr() = v.getARead() and
     strictcount(bb.getAPredecessor()) > 1 and
     exists(ConditionBlock cb | cb.getCondition() = ioe and cb.getTestSuccessor(true) = bb)
   }
 
   /** Holds if `bb` is disjunctively guarded by multiple `instanceof` tests on `v`. */
-  private predicate instanceofDisjunction(BasicBlock bb, BaseSsaVariable v) {
+  private predicate instanceofDisjunction(BasicBlock bb, Base::SsaDefinition v) {
     strictcount(InstanceOfExpr ioe | instanceofDisjunct(ioe, bb, v)) =
       strictcount(bb.getAPredecessor())
   }
@@ -338,10 +340,10 @@ private module Input implements TypeFlowInput<Location> {
    * `instanceof t_i` where `t` is one of those `t_i`.
    */
   predicate instanceofDisjunctionGuarded(TypeFlowNode n, RefType t) {
-    exists(BasicBlock bb, InstanceOfExpr ioe, BaseSsaVariable v, VarAccess va |
+    exists(BasicBlock bb, InstanceOfExpr ioe, Base::SsaDefinition v, VarAccess va |
       instanceofDisjunction(bb, v) and
       bb.dominates(va.getBasicBlock()) and
-      va = v.getAUse() and
+      va = v.getARead() and
       instanceofDisjunct(ioe, bb, v) and
       t = ioe.getSyntacticCheckedType() and
       n.asExpr() = va