Merge pull request #21268 from aschackmull/java/view-cfg

Java: Add support for "View CFG" in VSCode.

Author: aschackmull

java/ql/lib/printCfg.ql

@@ -0,0 +1,45 @@
+/**
+ * @name Print CFG
+ * @description Produces a representation of a file's Control Flow Graph.
+ *              This query is used by the VS Code extension.
+ * @id java/print-cfg
+ * @kind graph
+ * @tags ide-contextual-queries/print-cfg
+ */
+
+import java
+
+external string selectedSourceFile();
+
+private predicate selectedSourceFileAlias = selectedSourceFile/0;
+
+external int selectedSourceLine();
+
+private predicate selectedSourceLineAlias = selectedSourceLine/0;
+
+external int selectedSourceColumn();
+
+private predicate selectedSourceColumnAlias = selectedSourceColumn/0;
+
+module ViewCfgQueryInput implements ViewCfgQueryInputSig<File> {
+  predicate selectedSourceFile = selectedSourceFileAlias/0;
+
+  predicate selectedSourceLine = selectedSourceLineAlias/0;
+
+  predicate selectedSourceColumn = selectedSourceColumnAlias/0;
+
+  predicate cfgScopeSpan(
+    Callable callable, File file, int startLine, int startColumn, int endLine, int endColumn
+  ) {
+    file = callable.getFile() and
+    callable.getLocation().getStartLine() = startLine and
+    callable.getLocation().getStartColumn() = startColumn and
+    exists(Location loc |
+      loc.getEndLine() = endLine and
+      loc.getEndColumn() = endColumn and
+      loc = callable.getBody().getLocation()
+    )
+  }
+}
+
+import ViewCfgQuery<File, ViewCfgQueryInput>

java/ql/lib/semmle/code/java/ControlFlowGraph.qll

@@ -1775,3 +1775,17 @@ class ConditionNode extends ControlFlow::Node {
   /** Gets the condition of this `ConditionNode`. */
   ExprParent getCondition() { result = this.asExpr() or result = this.asStmt() }
 }
+
+private import codeql.controlflow.PrintGraph as PrintGraph
+
+private module PrintGraphInput implements PrintGraph::InputSig<Location> {
+  private import java as J
+
+  class Callable = J::Callable;
+
+  class ControlFlowNode = J::ControlFlowNode;
+
+  ControlFlowNode getASuccessor(ControlFlowNode n, SuccessorType t) { result = n.getASuccessor(t) }
+}
+
+import PrintGraph::PrintGraph<Location, PrintGraphInput>

shared/controlflow/codeql/controlflow/Cfg.qll

@@ -1122,6 +1122,9 @@ module MakeWithSplitting<
     /** Gets the scope of this node. */
     CfgScope getScope() { result = getNodeCfgScope(this) }
 
+    /** Gets the enclosing callable of this node. */
+    CfgScope getEnclosingCallable() { result = this.getScope() }
+
     /** Gets a successor node of a given type, if any. */
     Node getASuccessor(SuccessorType t) { result = getASuccessor(this, t) }
 
@@ -1310,160 +1313,19 @@ module MakeWithSplitting<
     }
   }
 
-  /** A node to be included in the output of `TestOutput`. */
-  signature class RelevantNodeSig extends Node;
-
-  /**
-   * Import this module into a `.ql` file to output a CFG. The
-   * graph is restricted to nodes from `RelevantNode`.
-   */
-  module TestOutput<RelevantNodeSig RelevantNode> {
-    /** Holds if `pred -> succ` is an edge in the CFG. */
-    query predicate edges(RelevantNode pred, RelevantNode succ, string label) {
-      label =
-        strictconcat(SuccessorType t, string s |
-          succ = getASuccessor(pred, t) and
-          if t instanceof DirectSuccessor then s = "" else s = t.toString()
-        |
-          s, ", " order by s
-        )
-    }
-
-    /**
-     * Provides logic for representing a CFG as a [Mermaid diagram](https://mermaid.js.org/).
-     */
-    module Mermaid {
-      private string nodeId(RelevantNode n) {
-        result =
-          any(int i |
-            n =
-              rank[i](RelevantNode p, string filePath, int startLine, int startColumn, int endLine,
-                int endColumn |
-                p.getLocation()
-                    .hasLocationInfo(filePath, startLine, startColumn, endLine, endColumn)
-              |
-                p order by filePath, startLine, startColumn, endLine, endColumn, p.toString()
-              )
-          ).toString()
-      }
-
-      private string nodes() {
-        result =
-          concat(RelevantNode n, string id, string text |
-            id = nodeId(n) and
-            text = n.toString()
-          |
-            id + "[\"" + text + "\"]", "\n" order by id
-          )
-      }
+  private import PrintGraph as Pp
 
-      private string edge(RelevantNode pred, RelevantNode succ) {
-        edges(pred, succ, _) and
-        exists(string label |
-          edges(pred, succ, label) and
-          if label = ""
-          then result = nodeId(pred) + " --> " + nodeId(succ)
-          else result = nodeId(pred) + " -- " + label + " --> " + nodeId(succ)
-        )
-      }
+  private module PrintGraphInput implements Pp::InputSig<Location> {
+    class Callable = CfgScope;
 
-      private string edges() {
-        result =
-          concat(RelevantNode pred, RelevantNode succ, string edge, string filePath, int startLine,
-            int startColumn, int endLine, int endColumn |
-            edge = edge(pred, succ) and
-            pred.getLocation().hasLocationInfo(filePath, startLine, startColumn, endLine, endColumn)
-          |
-            edge, "\n"
-            order by
-              filePath, startLine, startColumn, endLine, endColumn, pred.toString()
-          )
-      }
+    class ControlFlowNode = Node;
 
-      /** Holds if the Mermaid representation is `s`. */
-      query predicate mermaid(string s) { s = "flowchart TD\n" + nodes() + "\n\n" + edges() }
+    ControlFlowNode getASuccessor(ControlFlowNode n, SuccessorType t) {
+      result = n.getASuccessor(t)
     }
   }
 
-  /** Provides the input to `ViewCfgQuery`. */
-  signature module ViewCfgQueryInputSig<FileSig File> {
-    /** The source file selected in the IDE. Should be an `external` predicate. */
-    string selectedSourceFile();
-
-    /** The source line selected in the IDE. Should be an `external` predicate. */
-    int selectedSourceLine();
-
-    /** The source column selected in the IDE. Should be an `external` predicate. */
-    int selectedSourceColumn();
-
-    /**
-     * Holds if CFG scope `scope` spans column `startColumn` of line `startLine` to
-     * column `endColumn` of line `endLine` in `file`.
-     */
-    predicate cfgScopeSpan(
-      CfgScope scope, File file, int startLine, int startColumn, int endLine, int endColumn
-    );
-  }
-
-  /**
-   * Provides an implementation for a `View CFG` query.
-   *
-   * Import this module into a `.ql` that looks like
-   *
-   * ```ql
-   * @name Print CFG
-   * @description Produces a representation of a file's Control Flow Graph.
-   *              This query is used by the VS Code extension.
-   * @id <lang>/print-cfg
-   * @kind graph
-   * @tags ide-contextual-queries/print-cfg
-   * ```
-   */
-  module ViewCfgQuery<FileSig File, ViewCfgQueryInputSig<File> ViewCfgQueryInput> {
-    private import ViewCfgQueryInput
-
-    bindingset[file, line, column]
-    private CfgScope smallestEnclosingScope(File file, int line, int column) {
-      result =
-        min(CfgScope scope, int startLine, int startColumn, int endLine, int endColumn |
-          cfgScopeSpan(scope, file, startLine, startColumn, endLine, endColumn) and
-          (
-            startLine < line
-            or
-            startLine = line and startColumn <= column
-          ) and
-          (
-            endLine > line
-            or
-            endLine = line and endColumn >= column
-          )
-        |
-          scope order by startLine desc, startColumn desc, endLine, endColumn
-        )
-    }
-
-    private import IdeContextual<File>
-
-    private class RelevantNode extends Node {
-      RelevantNode() {
-        this.getScope() =
-          smallestEnclosingScope(getFileBySourceArchiveName(selectedSourceFile()),
-            selectedSourceLine(), selectedSourceColumn())
-      }
-
-      string getOrderDisambiguation() { result = "" }
-    }
-
-    private module Output = TestOutput<RelevantNode>;
-
-    import Output::Mermaid
-
-    /** Holds if `pred` -> `succ` is an edge in the CFG. */
-    query predicate edges(RelevantNode pred, RelevantNode succ, string attr, string val) {
-      attr = "semmle.label" and
-      Output::edges(pred, succ, val)
-    }
-  }
+  import Pp::PrintGraph<Location, PrintGraphInput>
 
   /** Provides a set of consistency queries. */
   module Consistency {