C++: Share some code by introducing a parameterized module to construct reasons.

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/rangeanalysis/new/internal/semantic/analysis/RangeAnalysisConstantSpecific.qll

@@ -3,60 +3,23 @@
  */
 
 private import semmle.code.cpp.rangeanalysis.new.internal.semantic.Semantic
+private import codeql.util.Unit
+private import Reason as Reason
 private import RangeAnalysisStage
 private import semmle.code.cpp.rangeanalysis.new.internal.semantic.analysis.FloatDelta
 
 module CppLangImplConstant implements LangSig<FloatDelta> {
-  private newtype TSemReason =
-    TSemNoReason() or
-    TSemCondReason(SemGuard guard) or
-    TSemTypeReason()
-
-  /**
-   * A reason for an inferred bound. This can either be `CondReason` if the bound
-   * is due to a specific condition, or `NoReason` if the bound is inferred
-   * without going through a bounding condition.
-   */
-  abstract class SemReason extends TSemReason {
-    /** Gets a textual representation of this reason. */
-    abstract string toString();
-
-    bindingset[this, reason]
-    abstract SemReason combineWith(SemReason reason);
-  }
-
-  /**
-   * A reason for an inferred bound that indicates that the bound is inferred
-   * without going through a bounding condition.
-   */
-  class SemNoReason extends SemReason, TSemNoReason {
-    override string toString() { result = "NoReason" }
-
-    override SemReason combineWith(SemReason reason) { result = reason }
+  private module Param implements Reason::ParamSig {
+    class TypeReasonImpl = Unit;
   }
 
-  /** A reason for an inferred bound pointing to a condition. */
-  class SemCondReason extends SemReason, TSemCondReason {
-    /** Gets the condition that is the reason for the bound. */
-    SemGuard getCond() { this = TSemCondReason(result) }
+  class SemReason = Reason::Make<Param>::SemReason;
 
-    override string toString() { result = this.getCond().toString() }
+  class SemNoReason = Reason::Make<Param>::SemNoReason;
 
-    bindingset[this, reason]
-    override SemReason combineWith(SemReason reason) {
-      if reason instanceof SemTypeReason then result instanceof SemTypeReason else result = this
-    }
-  }
+  class SemCondReason = Reason::Make<Param>::SemCondReason;
 
-  /**
-   * A reason for an inferred bound that indicates that the bound is inferred
-   * based on type-information.
-   */
-  class SemTypeReason extends SemReason, TSemTypeReason {
-    override string toString() { result = "TypeReason" }
-
-    override SemReason combineWith(SemReason reason) { result = this and exists(reason) }
-  }
+  class SemTypeReason = Reason::Make<Param>::SemTypeReason;
 
   /**
    * Holds if the specified expression should be excluded from the result of `ssaRead()`.

cpp/ql/lib/semmle/code/cpp/rangeanalysis/new/internal/semantic/analysis/RangeAnalysisRelativeSpecific.qll

@@ -7,60 +7,24 @@ private import RangeAnalysisStage
 private import semmle.code.cpp.rangeanalysis.new.internal.semantic.analysis.FloatDelta
 private import semmle.code.cpp.rangeanalysis.new.internal.semantic.analysis.IntDelta
 private import RangeAnalysisImpl
+private import codeql.util.Unit
+private import Reason as Reason
 private import semmle.code.cpp.rangeanalysis.RangeAnalysisUtils
 
 module CppLangImplRelative implements LangSig<FloatDelta> {
-  private newtype TSemReason =
-    TSemNoReason() or
-    TSemCondReason(SemGuard guard)
-
-  /**
-   * A reason for an inferred bound. This can either be `CondReason` if the bound
-   * is due to a specific condition, or `NoReason` if the bound is inferred
-   * without going through a bounding condition.
-   */
-  abstract class SemReason extends TSemReason {
-    /** Gets a textual representation of this reason. */
-    abstract string toString();
-
-    bindingset[this, reason]
-    abstract SemReason combineWith(SemReason reason);
-  }
-
-  /**
-   * A reason for an inferred boudn that indicates that the bound is inferred
-   * based on type-information.
-   *
-   * NOTE: The relative stage does not infer any bounds based on type-information.
-   */
-  class SemTypeReason extends SemReason {
-    SemTypeReason() { none() }
-
-    override string toString() { result = "TypeReason" }
-
-    override SemReason combineWith(SemReason reason) { none() }
+  private module Param implements Reason::ParamSig {
+    class TypeReasonImpl extends Unit {
+      TypeReasonImpl() { none() }
+    }
   }
 
-  /**
-   * A reason for an inferred bound that indicates that the bound is inferred
-   * without going through a bounding condition.
-   */
-  class SemNoReason extends SemReason, TSemNoReason {
-    override string toString() { result = "NoReason" }
-
-    override SemReason combineWith(SemReason reason) { result = reason }
-  }
+  class SemReason = Reason::Make<Param>::SemReason;
 
-  /** A reason for an inferred bound pointing to a condition. */
-  class SemCondReason extends SemReason, TSemCondReason {
-    /** Gets the condition that is the reason for the bound. */
-    SemGuard getCond() { this = TSemCondReason(result) }
+  class SemNoReason = Reason::Make<Param>::SemNoReason;
 
-    override string toString() { result = this.getCond().toString() }
+  class SemCondReason = Reason::Make<Param>::SemCondReason;
 
-    bindingset[this, reason]
-    override SemReason combineWith(SemReason reason) { result = reason }
-  }
+  class SemTypeReason = Reason::Make<Param>::SemTypeReason;
 
   /**
    * Holds if the specified expression should be excluded from the result of `ssaRead()`.

cpp/ql/lib/semmle/code/cpp/rangeanalysis/new/internal/semantic/analysis/Reason.qll

@@ -0,0 +1,73 @@
+/**
+ * Provides a `Make` parameterized module for constructing a `Reason` type that is used
+ * when implementing the `LangSig` module.
+ */
+
+private import semmle.code.cpp.rangeanalysis.new.internal.semantic.Semantic
+
+/** The necessary parameters that must be implemented to instantiate `Make`. */
+signature module ParamSig {
+  class TypeReasonImpl;
+}
+
+/**
+ * The module that constructs a `Reason` type when provided with an implementation
+ * of `ParamSig`.
+ */
+module Make<ParamSig Param> {
+  private import Param
+
+  private newtype TSemReason =
+    TSemNoReason() or
+    TSemCondReason(SemGuard guard) or
+    TSemTypeReason(TypeReasonImpl trc)
+
+  /**
+   * A reason for an inferred bound. This can either be `CondReason` if the bound
+   * is due to a specific condition, or `NoReason` if the bound is inferred
+   * without going through a bounding condition.
+   */
+  abstract class SemReason extends TSemReason {
+    /** Gets a textual representation of this reason. */
+    abstract string toString();
+
+    bindingset[this, reason]
+    abstract SemReason combineWith(SemReason reason);
+  }
+
+  /**
+   * A reason for an inferred bound that indicates that the bound is inferred
+   * without going through a bounding condition.
+   */
+  class SemNoReason extends SemReason, TSemNoReason {
+    override string toString() { result = "NoReason" }
+
+    override SemReason combineWith(SemReason reason) { result = reason }
+  }
+
+  /** A reason for an inferred bound pointing to a condition. */
+  class SemCondReason extends SemReason, TSemCondReason {
+    /** Gets the condition that is the reason for the bound. */
+    SemGuard getCond() { this = TSemCondReason(result) }
+
+    override string toString() { result = this.getCond().toString() }
+
+    bindingset[this, reason]
+    override SemReason combineWith(SemReason reason) {
+      if reason instanceof SemTypeReason then result instanceof SemTypeReason else result = this
+    }
+  }
+
+  /**
+   * A reason for an inferred bound that indicates that the bound is inferred
+   * based on type-information.
+   */
+  class SemTypeReason extends SemReason, TSemTypeReason {
+    TypeReasonImpl impl;
+
+    override string toString() { result = "TypeReason" }
+
+    bindingset[this, reason]
+    override SemReason combineWith(SemReason reason) { result = this and exists(reason) }
+  }
+}