C++: Revert semmle.code.cpp.dataflow to its old state

While here make sure all queries and tests use IR dataflow when appropriate.

cpp/ql/lib/semmle/code/cpp/dataflow/DataFlow.qll

@@ -4,7 +4,10 @@
  * _sink_.
  *
  * Unless configured otherwise, _flow_ means that the exact value of
- * the source may reach the sink.
+ * the source may reach the sink. We do not track flow across pointer
+ * dereferences or array indexing. To track these types of flow, where the
+ * exact value may not be preserved, import
+ * `semmle.code.cpp.dataflow.TaintTracking`.
  *
  * To use global (interprocedural) data flow, extend the class
  * `DataFlow::Configuration` as documented on that class. To use local
@@ -14,4 +17,12 @@
  * `DataFlow::Node`.
  */
 
-import semmle.code.cpp.ir.dataflow.DataFlow
+import cpp
+
+/**
+ * Provides classes for performing local (intra-procedural) and
+ * global (inter-procedural) data flow analyses.
+ */
+module DataFlow {
+  import semmle.code.cpp.dataflow.internal.DataFlowImpl
+}

cpp/ql/lib/semmle/code/cpp/dataflow/DataFlow2.qll

@@ -9,4 +9,12 @@
  * See `semmle.code.cpp.dataflow.DataFlow` for the full documentation.
  */
 
-import semmle.code.cpp.ir.dataflow.DataFlow2
+import cpp
+
+/**
+ * Provides classes for performing local (intra-procedural) and
+ * global (inter-procedural) data flow analyses.
+ */
+module DataFlow2 {
+  import semmle.code.cpp.dataflow.internal.DataFlowImpl2
+}

cpp/ql/lib/semmle/code/cpp/dataflow/DataFlow3.qll

@@ -9,4 +9,12 @@
  * See `semmle.code.cpp.dataflow.DataFlow` for the full documentation.
  */
 
-import semmle.code.cpp.ir.dataflow.DataFlow3
+import cpp
+
+/**
+ * Provides classes for performing local (intra-procedural) and
+ * global (inter-procedural) data flow analyses.
+ */
+module DataFlow3 {
+  import semmle.code.cpp.dataflow.internal.DataFlowImpl3
+}

cpp/ql/lib/semmle/code/cpp/dataflow/DataFlow4.qll

@@ -9,4 +9,12 @@
  * See `semmle.code.cpp.dataflow.DataFlow` for the full documentation.
  */
 
-import semmle.code.cpp.ir.dataflow.DataFlow4
+import cpp
+
+/**
+ * Provides classes for performing local (intra-procedural) and
+ * global (inter-procedural) data flow analyses.
+ */
+module DataFlow4 {
+  import semmle.code.cpp.dataflow.internal.DataFlowImpl4
+}

cpp/ql/lib/semmle/code/cpp/dataflow/TaintTracking.qll

@@ -15,4 +15,13 @@
  * `TaintTracking::localTaintStep` with arguments of type `DataFlow::Node`.
  */
 
-import semmle.code.cpp.ir.dataflow.TaintTracking
+import semmle.code.cpp.dataflow.DataFlow
+import semmle.code.cpp.dataflow.DataFlow2
+
+/**
+ * Provides classes for performing local (intra-procedural) and
+ * global (inter-procedural) taint-tracking analyses.
+ */
+module TaintTracking {
+  import semmle.code.cpp.dataflow.internal.tainttracking1.TaintTrackingImpl
+}

cpp/ql/lib/semmle/code/cpp/dataflow/TaintTracking2.qll

@@ -11,4 +11,10 @@
  * See `semmle.code.cpp.dataflow.TaintTracking` for the full documentation.
  */
 
-import semmle.code.cpp.ir.dataflow.TaintTracking2
+/**
+ * Provides classes for performing local (intra-procedural) and
+ * global (inter-procedural) taint-tracking analyses.
+ */
+module TaintTracking2 {
+  import semmle.code.cpp.dataflow.internal.tainttracking2.TaintTrackingImpl
+}

cpp/ql/lib/semmle/code/cpp/dataflow/TaintTracking3.qll

@@ -1,14 +0,0 @@
-/**
- * Provides a `TaintTracking3` module, which is a copy of the `TaintTracking`
- * module. Use this class when data-flow configurations or taint-tracking
- * configurations must depend on each other. Two classes extending
- * `DataFlow::Configuration` should never depend on each other, but one of them
- * should instead depend on a `DataFlow2::Configuration`, a
- * `DataFlow3::Configuration`, or a `DataFlow4::Configuration`. The
- * `TaintTracking::Configuration` class extends `DataFlow::Configuration`, and
- * `TaintTracking2::Configuration` extends `DataFlow2::Configuration`.
- *
- * See `semmle.code.cpp.dataflow.TaintTracking` for the full documentation.
- */
-
-import semmle.code.cpp.ir.dataflow.TaintTracking3

cpp/ql/lib/semmle/code/cpp/dataflow/internal/tainttracking1/TaintTrackingParameter.qll

@@ -0,0 +1,5 @@
+import semmle.code.cpp.dataflow.internal.TaintTrackingUtil as Public
+
+module Private {
+  import semmle.code.cpp.dataflow.DataFlow::DataFlow as DataFlow
+}

cpp/ql/lib/semmle/code/cpp/dataflow/internal/tainttracking2/TaintTrackingParameter.qll

@@ -0,0 +1,5 @@
+import semmle.code.cpp.dataflow.internal.TaintTrackingUtil as Public
+
+module Private {
+  import semmle.code.cpp.dataflow.DataFlow2::DataFlow2 as DataFlow
+}

cpp/ql/lib/semmle/code/cpp/dataflow/old/DataFlow.qll

@@ -1,25 +0,0 @@
-/**
- * Provides a library for local (intra-procedural) and global (inter-procedural)
- * data flow analysis: deciding whether data can flow from a _source_ to a
- * _sink_.
- *
- * Unless configured otherwise, _flow_ means that the exact value of
- * the source may reach the sink.
- *
- * To use global (interprocedural) data flow, extend the class
- * `DataFlow::Configuration` as documented on that class. To use local
- * (intraprocedural) data flow between expressions, call
- * `DataFlow::localExprFlow`. For more general cases of local data flow, call
- * `DataFlow::localFlow` or `DataFlow::localFlowStep` with arguments of type
- * `DataFlow::Node`.
- */
-
-import cpp
-
-/**
- * Provides classes for performing local (intra-procedural) and
- * global (inter-procedural) data flow analyses.
- */
-module DataFlow {
-  import semmle.code.cpp.dataflow.old.internal.DataFlowImpl
-}

cpp/ql/lib/semmle/code/cpp/dataflow/old/DataFlow2.qll

@@ -1,20 +0,0 @@
-/**
- * Provides a `DataFlow2` module, which is a copy of the `DataFlow` module. Use
- * this class when data-flow configurations must depend on each other. Two
- * classes extending `DataFlow::Configuration` should never depend on each
- * other, but one of them should instead depend on a
- * `DataFlow2::Configuration`, a `DataFlow3::Configuration`, or a
- * `DataFlow4::Configuration`.
- *
- * See `semmle.code.cpp.dataflow.old.DataFlow` for the full documentation.
- */
-
-import cpp
-
-/**
- * Provides classes for performing local (intra-procedural) and
- * global (inter-procedural) data flow analyses.
- */
-module DataFlow2 {
-  import semmle.code.cpp.dataflow.old.internal.DataFlowImpl2
-}

cpp/ql/lib/semmle/code/cpp/dataflow/old/DataFlow3.qll

@@ -1,20 +0,0 @@
-/**
- * Provides a `DataFlow3` module, which is a copy of the `DataFlow` module. Use
- * this class when data-flow configurations must depend on each other. Two
- * classes extending `DataFlow::Configuration` should never depend on each
- * other, but one of them should instead depend on a
- * `DataFlow2::Configuration`, a `DataFlow3::Configuration`, or a
- * `DataFlow4::Configuration`.
- *
- * See `semmle.code.cpp.dataflow.old.DataFlow` for the full documentation.
- */
-
-import cpp
-
-/**
- * Provides classes for performing local (intra-procedural) and
- * global (inter-procedural) data flow analyses.
- */
-module DataFlow3 {
-  import semmle.code.cpp.dataflow.old.internal.DataFlowImpl3
-}

cpp/ql/lib/semmle/code/cpp/dataflow/old/DataFlow4.qll

@@ -1,20 +0,0 @@
-/**
- * Provides a `DataFlow4` module, which is a copy of the `DataFlow` module. Use
- * this class when data-flow configurations must depend on each other. Two
- * classes extending `DataFlow::Configuration` should never depend on each
- * other, but one of them should instead depend on a
- * `DataFlow2::Configuration`, a `DataFlow3::Configuration`, or a
- * `DataFlow4::Configuration`.
- *
- * See `semmle.code.cpp.dataflow.old.DataFlow` for the full documentation.
- */
-
-import cpp
-
-/**
- * Provides classes for performing local (intra-procedural) and
- * global (inter-procedural) data flow analyses.
- */
-module DataFlow4 {
-  import semmle.code.cpp.dataflow.old.internal.DataFlowImpl4
-}

cpp/ql/lib/semmle/code/cpp/dataflow/old/RecursionPrevention.qll

@@ -1,39 +0,0 @@
-/**
- * DEPRECATED: Recursion through `DataFlow::Configuration` is impossible in
- * any supported tooling. There is no need for this module because it's
- * impossible to accidentally depend on recursion through
- * `DataFlow::Configuration` in current releases.
- *
- * When this module is imported, recursive use of `DataFlow::Configuration` is
- * disallowed. Importing this module will guarantee the absence of such
- * recursion, which is unsupported and will be unconditionally disallowed in a
- * future release.
- *
- * Recursive use of `DataFlow{2..4}::Configuration` is always disallowed, so no
- * import is needed for those.
- */
-
-import cpp
-private import semmle.code.cpp.dataflow.DataFlow
-
-/**
- * This class exists to prevent mutual recursion between the user-overridden
- * member predicates of `Configuration` and the rest of the data-flow library.
- * Good performance cannot be guaranteed in the presence of such recursion, so
- * it should be replaced by using more than one copy of the data flow library.
- * Four copies are available: `DataFlow` through `DataFlow4`.
- */
-abstract private class ConfigurationRecursionPrevention extends DataFlow::Configuration {
-  bindingset[this]
-  ConfigurationRecursionPrevention() { any() }
-
-  override predicate hasFlow(DataFlow::Node source, DataFlow::Node sink) {
-    strictcount(DataFlow::Node n | this.isSource(n)) < 0
-    or
-    strictcount(DataFlow::Node n | this.isSink(n)) < 0
-    or
-    strictcount(DataFlow::Node n1, DataFlow::Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
-    or
-    super.hasFlow(source, sink)
-  }
-}

cpp/ql/lib/semmle/code/cpp/dataflow/old/TaintTracking.qll

@@ -1,27 +0,0 @@
-/**
- * Provides classes for performing local (intra-procedural) and
- * global (inter-procedural) taint-tracking analyses.
- *
- * We define _taint propagation_ informally to mean that a substantial part of
- * the information from the source is preserved at the sink. For example, taint
- * propagates from `x` to `x + 100`, but it does not propagate from `x` to `x >
- * 100` since we consider a single bit of information to be too little.
- *
- * To use global (interprocedural) taint tracking, extend the class
- * `TaintTracking::Configuration` as documented on that class. To use local
- * (intraprocedural) taint tracking between expressions, call
- * `TaintTracking::localExprTaint`. For more general cases of local taint
- * tracking, call `TaintTracking::localTaint` or
- * `TaintTracking::localTaintStep` with arguments of type `DataFlow::Node`.
- */
-
-import semmle.code.cpp.dataflow.old.DataFlow
-import semmle.code.cpp.dataflow.old.DataFlow2
-
-/**
- * Provides classes for performing local (intra-procedural) and
- * global (inter-procedural) taint-tracking analyses.
- */
-module TaintTracking {
-  import semmle.code.cpp.dataflow.old.internal.tainttracking1.TaintTrackingImpl
-}

cpp/ql/lib/semmle/code/cpp/dataflow/old/TaintTracking2.qll

@@ -1,20 +0,0 @@
-/**
- * Provides a `TaintTracking2` module, which is a copy of the `TaintTracking`
- * module. Use this class when data-flow configurations or taint-tracking
- * configurations must depend on each other. Two classes extending
- * `DataFlow::Configuration` should never depend on each other, but one of them
- * should instead depend on a `DataFlow2::Configuration`, a
- * `DataFlow3::Configuration`, or a `DataFlow4::Configuration`. The
- * `TaintTracking::Configuration` class extends `DataFlow::Configuration`, and
- * `TaintTracking2::Configuration` extends `DataFlow2::Configuration`.
- *
- * See `semmle.code.cpp.dataflow.old.TaintTracking` for the full documentation.
- */
-
-/**
- * Provides classes for performing local (intra-procedural) and
- * global (inter-procedural) taint-tracking analyses.
- */
-module TaintTracking2 {
-  import semmle.code.cpp.dataflow.old.internal.tainttracking2.TaintTrackingImpl
-}

cpp/ql/lib/semmle/code/cpp/dataflow/old/internal/tainttracking1/TaintTrackingParameter.qll

@@ -1,5 +0,0 @@
-import semmle.code.cpp.dataflow.old.internal.TaintTrackingUtil as Public
-
-module Private {
-  import semmle.code.cpp.dataflow.old.DataFlow::DataFlow as DataFlow
-}

cpp/ql/lib/semmle/code/cpp/dataflow/old/internal/tainttracking2/TaintTrackingParameter.qll

@@ -1,5 +0,0 @@
-import semmle.code.cpp.dataflow.old.internal.TaintTrackingUtil as Public
-
-module Private {
-  import semmle.code.cpp.dataflow.old.DataFlow2::DataFlow2 as DataFlow
-}