Add initial mapping of CFG nodes to AST nodes

Author: hvitved

ql/consistency-queries/SsaConsistency.ql

@@ -3,20 +3,20 @@ import codeql_ruby.dataflow.SSA
 import codeql_ruby.controlflow.ControlFlowGraph
 
 query predicate nonUniqueDef(CfgNode read, Ssa::Definition def) {
-  read = def.getARead(_) and
-  exists(Ssa::Definition other | read = other.getARead(_) and other != def)
+  read = def.getARead() and
+  exists(Ssa::Definition other | read = other.getARead() and other != def)
 }
 
 query predicate readWithoutDef(LocalVariableReadAccess read) {
   exists(CfgNode node |
     node = read.getAControlFlowNode() and
-    not node = any(Ssa::Definition def).getARead(_)
+    not node = any(Ssa::Definition def).getARead()
   )
 }
 
 query predicate deadDef(Ssa::Definition def, LocalVariable v) {
   v = def.getSourceVariable() and
   not v.isCaptured() and
-  not exists(def.getARead(_)) and
+  not exists(def.getARead()) and
   not def = any(Ssa::PhiNode phi).getAnInput()
 }

ql/src/codeql_ruby/CFG.qll

@@ -0,0 +1,5 @@
+/** Provides classes representing the control flow graph. */
+
+import controlflow.ControlFlowGraph
+import controlflow.CfgNodes as CfgNodes
+import controlflow.BasicBlocks

ql/src/codeql_ruby/ast/Expr.qll

@@ -1,5 +1,5 @@
 private import codeql_ruby.AST
-private import codeql_ruby.controlflow.ControlFlowGraph
+private import codeql_ruby.CFG
 private import internal.Expr
 private import internal.Variable
 private import codeql_ruby.controlflow.internal.ControlFlowGraphImpl

ql/src/codeql_ruby/ast/Parameter.qll

@@ -22,10 +22,10 @@ class Parameter extends AstNode {
   final int getPosition() { result = pos }
 
   /** Gets a variable introduced by this parameter. */
-  Variable getAVariable() { none() }
+  LocalVariable getAVariable() { none() }
 
   /** Gets the variable named `name` introduced by this parameter. */
-  final Variable getVariable(string name) {
+  final LocalVariable getVariable(string name) {
     result = this.getAVariable() and
     result.getName() = name
   }
@@ -37,7 +37,7 @@ class Parameter extends AstNode {
  * This includes both simple parameters and tuple parameters.
  */
 class PatternParameter extends Parameter, Pattern {
-  override Variable getAVariable() { result = Pattern.super.getAVariable() }
+  override LocalVariable getAVariable() { result = Pattern.super.getAVariable() }
 }
 
 /** A parameter defined using a tuple pattern. */
@@ -53,9 +53,9 @@ class NamedParameter extends Parameter {
   string getName() { none() }
 
   /** Gets the variable introduced by this parameter. */
-  Variable getVariable() { none() }
+  LocalVariable getVariable() { none() }
 
-  override Variable getAVariable() { result = this.getVariable() }
+  override LocalVariable getAVariable() { result = this.getVariable() }
 
   /** Gets an access to this parameter. */
   final VariableAccess getAnAccess() { result = this.getVariable().getAnAccess() }
@@ -65,9 +65,9 @@ class NamedParameter extends Parameter {
 class SimpleParameter extends NamedParameter, PatternParameter, VariablePattern {
   final override string getName() { result = range.getVariableName() }
 
-  final override Variable getVariable() { result = TLocalVariable(_, _, this) }
+  final override LocalVariable getVariable() { result = TLocalVariable(_, _, this) }
 
-  final override Variable getAVariable() { result = this.getVariable() }
+  final override LocalVariable getAVariable() { result = this.getVariable() }
 
   final override string getAPrimaryQlClass() { result = "SimpleParameter" }
 
@@ -85,7 +85,7 @@ class SimpleParameter extends NamedParameter, PatternParameter, VariablePattern
 class BlockParameter extends @block_parameter, NamedParameter {
   final override Generated::BlockParameter generated;
 
-  final override Variable getVariable() { result = TLocalVariable(_, _, generated.getName()) }
+  final override LocalVariable getVariable() { result = TLocalVariable(_, _, generated.getName()) }
 
   final override string getAPrimaryQlClass() { result = "BlockParameter" }
 
@@ -106,7 +106,7 @@ class BlockParameter extends @block_parameter, NamedParameter {
 class HashSplatParameter extends @hash_splat_parameter, NamedParameter {
   final override Generated::HashSplatParameter generated;
 
-  final override Variable getVariable() { result = TLocalVariable(_, _, generated.getName()) }
+  final override LocalVariable getVariable() { result = TLocalVariable(_, _, generated.getName()) }
 
   final override string getAPrimaryQlClass() { result = "HashSplatParameter" }
 
@@ -129,7 +129,7 @@ class HashSplatParameter extends @hash_splat_parameter, NamedParameter {
 class KeywordParameter extends @keyword_parameter, NamedParameter {
   final override Generated::KeywordParameter generated;
 
-  final override Variable getVariable() { result = TLocalVariable(_, _, generated.getName()) }
+  final override LocalVariable getVariable() { result = TLocalVariable(_, _, generated.getName()) }
 
   final override string getAPrimaryQlClass() { result = "KeywordParameter" }
 
@@ -164,7 +164,7 @@ class KeywordParameter extends @keyword_parameter, NamedParameter {
 class OptionalParameter extends @optional_parameter, NamedParameter {
   final override Generated::OptionalParameter generated;
 
-  final override Variable getVariable() { result = TLocalVariable(_, _, generated.getName()) }
+  final override LocalVariable getVariable() { result = TLocalVariable(_, _, generated.getName()) }
 
   final override string getAPrimaryQlClass() { result = "OptionalParameter" }
 
@@ -191,7 +191,7 @@ class OptionalParameter extends @optional_parameter, NamedParameter {
 class SplatParameter extends @splat_parameter, NamedParameter {
   final override Generated::SplatParameter generated;
 
-  final override Variable getVariable() { result = TLocalVariable(_, _, generated.getName()) }
+  final override LocalVariable getVariable() { result = TLocalVariable(_, _, generated.getName()) }
 
   final override string getAPrimaryQlClass() { result = "SplatParameter" }
 

ql/src/codeql_ruby/ast/Variable.qll

@@ -50,13 +50,6 @@ class Variable extends TVariable {
 
   /** Gets an access to this variable. */
   VariableAccess getAnAccess() { result.getVariable() = this }
-
-  /**
-   * Gets the access where this variable is first introduced, if any.
-   *
-   * Global variables do not have a defining access.
-   */
-  VariableAccess getDefiningAccess() { result = range.getDefiningAccess() }
 }
 
 /** A local variable. */
@@ -65,6 +58,9 @@ class LocalVariable extends Variable, TLocalVariable {
 
   final override LocalVariableAccess getAnAccess() { result.getVariable() = this }
 
+  /** Gets the access where this local variable is first introduced. */
+  VariableAccess getDefiningAccess() { result = range.getDefiningAccess() }
+
   /**
    * Holds if this variable is captured. For example in
    *

ql/src/codeql_ruby/ast/internal/Variable.qll

@@ -378,8 +378,6 @@ module Variable {
     abstract Location getLocation();
 
     abstract VariableScope getDeclaringScope();
-
-    abstract VariableAccess getDefiningAccess();
   }
 }
 
@@ -397,7 +395,7 @@ module LocalVariable {
 
     final override VariableScope getDeclaringScope() { result = scope }
 
-    final override VariableAccess getDefiningAccess() { result = i }
+    final VariableAccess getDefiningAccess() { result = i }
   }
 }
 
@@ -412,8 +410,6 @@ module GlobalVariable {
     final override Location getLocation() { none() }
 
     final override VariableScope getDeclaringScope() { result = TGlobalScope() }
-
-    final override VariableAccess getDefiningAccess() { none() }
   }
 }
 

ql/src/codeql_ruby/controlflow/BasicBlocks.qll

@@ -4,6 +4,7 @@ private import codeql.Locations
 private import codeql_ruby.ast.internal.TreeSitter::Generated
 private import codeql_ruby.controlflow.ControlFlowGraph
 private import internal.ControlFlowGraphImpl
+private import CfgNodes
 private import SuccessorTypes
 
 /**
@@ -286,9 +287,7 @@ private module Cached {
   private predicate predBB(BasicBlock succ, BasicBlock pred) { succBB(pred, succ) }
 
   /** Holds if `bb` is an exit basic block that represents normal exit. */
-  private predicate normalExitBB(BasicBlock bb) {
-    bb.getANode().(CfgNodes::AnnotatedExitNode).isNormal()
-  }
+  private predicate normalExitBB(BasicBlock bb) { bb.getANode().(AnnotatedExitNode).isNormal() }
 
   /** Holds if `dom` is an immediate post-dominator of `bb`. */
   cached
@@ -313,7 +312,7 @@ private module Cached {
 private import Cached
 
 /** Holds if `bb` is an entry basic block. */
-private predicate entryBB(BasicBlock bb) { bb.getFirstNode() instanceof CfgNodes::EntryNode }
+private predicate entryBB(BasicBlock bb) { bb.getFirstNode() instanceof EntryNode }
 
 /**
  * An entry basic block, that is, a basic block whose first node is
@@ -333,7 +332,7 @@ class AnnotatedExitBasicBlock extends BasicBlock {
   private boolean normal;
 
   AnnotatedExitBasicBlock() {
-    exists(CfgNodes::AnnotatedExitNode n |
+    exists(AnnotatedExitNode n |
       n = this.getANode() and
       if n.isNormal() then normal = true else normal = false
     )
@@ -348,12 +347,10 @@ class AnnotatedExitBasicBlock extends BasicBlock {
  * an exit node.
  */
 class ExitBasicBlock extends BasicBlock {
-  ExitBasicBlock() { this.getLastNode() instanceof CfgNodes::ExitNode }
+  ExitBasicBlock() { this.getLastNode() instanceof ExitNode }
 }
 
 private module JoinBlockPredecessors {
-  private import CfgNodes
-
   private predicate id(AstNode x, AstNode y) { x = y }
 
   private predicate idOf(AstNode x, int y) = equivalenceRelation(id/2)(x, y)