Merge pull request #11074 from github/revert-10576-ssa/consistency-queries

Revert "SSA: Turn consistency predicates into `query` predicates"

csharp/ql/consistency-queries/SsaConsistency.ql

@@ -1,8 +1,8 @@
 import csharp
-import semmle.code.csharp.dataflow.internal.SsaImpl::Consistency
+import semmle.code.csharp.dataflow.internal.SsaImpl::Consistency as Consistency
 import Ssa
 
-class MyRelevantDefinition extends RelevantDefinition, Ssa::Definition {
+class MyRelevantDefinition extends Consistency::RelevantDefinition, Ssa::Definition {
   override predicate hasLocationInfo(
     string filepath, int startline, int startcolumn, int endline, int endcolumn
   ) {
@@ -10,6 +10,14 @@ class MyRelevantDefinition extends RelevantDefinition, Ssa::Definition {
   }
 }
 
+query predicate nonUniqueDef = Consistency::nonUniqueDef/4;
+
+query predicate readWithoutDef = Consistency::readWithoutDef/3;
+
+query predicate deadDef = Consistency::deadDef/2;
+
+query predicate notDominatedByDef = Consistency::notDominatedByDef/4;
+
 query predicate localDeclWithSsaDef(LocalVariableDeclExpr d) {
   // Local variables in C# must be initialized before every use, so uninitialized
   // local variables should not have an SSA definition, as that would imply that

ruby/ql/consistency-queries/SsaConsistency.ql

@@ -1,10 +1,18 @@
 import codeql.ruby.dataflow.SSA
-import codeql.ruby.dataflow.internal.SsaImpl::Consistency
+import codeql.ruby.dataflow.internal.SsaImpl::Consistency as Consistency
 
-class MyRelevantDefinition extends RelevantDefinition, Ssa::Definition {
+class MyRelevantDefinition extends Consistency::RelevantDefinition, Ssa::Definition {
   override predicate hasLocationInfo(
     string filepath, int startline, int startcolumn, int endline, int endcolumn
   ) {
     this.getLocation().hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
   }
 }
+
+query predicate nonUniqueDef = Consistency::nonUniqueDef/4;
+
+query predicate readWithoutDef = Consistency::readWithoutDef/3;
+
+query predicate deadDef = Consistency::deadDef/2;
+
+query predicate notDominatedByDef = Consistency::notDominatedByDef/4;

shared/ssa/codeql/ssa/Ssa.qll

@@ -9,10 +9,7 @@ signature module InputSig {
    * A basic block, that is, a maximal straight-line sequence of control flow nodes
    * without branches or joins.
    */
-  class BasicBlock {
-    /** Gets a textual representation of this basic block. */
-    string toString();
-  }
+  class BasicBlock;
 
   /**
    * Gets the basic block that immediately dominates basic block `bb`, if any.
@@ -46,10 +43,7 @@ signature module InputSig {
   class ExitBasicBlock extends BasicBlock;
 
   /** A variable that can be SSA converted. */
-  class SourceVariable {
-    /** Gets a textual representation of this variable. */
-    string toString();
-  }
+  class SourceVariable;
 
   /**
    * Holds if the `i`th node of basic block `bb` is a (potential) write to source
@@ -852,6 +846,8 @@ module Make<InputSig Input> {
   }
 
   /** Provides a set of consistency queries. */
+  // TODO: Make these `query` predicates once class signatures are supported
+  // (`SourceVariable` and `BasicBlock` must have `toString`)
   module Consistency {
     /** A definition that is relevant for the consistency queries. */
     abstract class RelevantDefinition extends Definition {
@@ -862,19 +858,19 @@ module Make<InputSig Input> {
     }
 
     /** Holds if a read can be reached from multiple definitions. */
-    query predicate nonUniqueDef(RelevantDefinition def, SourceVariable v, BasicBlock bb, int i) {
+    predicate nonUniqueDef(RelevantDefinition def, SourceVariable v, BasicBlock bb, int i) {
       ssaDefReachesRead(v, def, bb, i) and
       not exists(unique(Definition def0 | ssaDefReachesRead(v, def0, bb, i)))
     }
 
     /** Holds if a read cannot be reached from a definition. */
-    query predicate readWithoutDef(SourceVariable v, BasicBlock bb, int i) {
+    predicate readWithoutDef(SourceVariable v, BasicBlock bb, int i) {
       variableRead(bb, i, v, _) and
       not ssaDefReachesRead(v, _, bb, i)
     }
 
     /** Holds if a definition cannot reach a read. */
-    query predicate deadDef(RelevantDefinition def, SourceVariable v) {
+    predicate deadDef(RelevantDefinition def, SourceVariable v) {
       v = def.getSourceVariable() and
       not ssaDefReachesRead(_, def, _, _) and
       not phiHasInputFromBlock(_, def, _) and
@@ -882,7 +878,7 @@ module Make<InputSig Input> {
     }
 
     /** Holds if a read is not dominated by a definition. */
-    query predicate notDominatedByDef(RelevantDefinition def, SourceVariable v, BasicBlock bb, int i) {
+    predicate notDominatedByDef(RelevantDefinition def, SourceVariable v, BasicBlock bb, int i) {
       exists(BasicBlock bbDef, int iDef | def.definesAt(v, bbDef, iDef) |
         ssaDefReachesReadWithinBlock(v, def, bb, i) and
         (bb != bbDef or i < iDef)