Extract define directives

csharp/extractor/Semmle.Extraction.CSharp/Entities/PreprocessorDirectives/DefineDirective.cs

@@ -0,0 +1,18 @@
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using System.IO;
+
+namespace Semmle.Extraction.CSharp.Entities
+{
+    internal class DefineDirective : PreprocessorDirective<DefineDirectiveTriviaSyntax>
+    {
+        public DefineDirective(Context cx, DefineDirectiveTriviaSyntax trivia)
+            : base(cx, trivia)
+        {
+        }
+
+        protected override void PopulatePreprocessor(TextWriter trapFile)
+        {
+            trapFile.directive_defines(this, trivia.Name.ToString());
+        }
+    }
+}

csharp/extractor/Semmle.Extraction.CSharp/Populators/DirectiveVisitor.cs

@@ -22,5 +22,10 @@ namespace Semmle.Extraction.CSharp.Populators
         {
             new Entities.PragmaChecksumDirective(cx, node);
         }
+
+        public override void VisitDefineDirectiveTrivia(DefineDirectiveTriviaSyntax node)
+        {
+            new Entities.DefineDirective(cx, node);
+        }
     }
 }

csharp/extractor/Semmle.Extraction.CSharp/Tuples.cs

@@ -620,5 +620,10 @@ namespace Semmle.Extraction.CSharp
         {
             trapFile.WriteTuple("pragma_checksums", pragma, file, guid, bytes);
         }
+
+        internal static void directive_defines(this TextWriter trapFile, DefineDirective directive, string name)
+        {
+            trapFile.WriteTuple("directive_defines", directive, name);
+        }
     }
 }

csharp/ql/src/semmle/code/csharp/Preprocessor.qll

@@ -46,3 +46,15 @@ class PragmaChecksumDirective extends PreprocessorDirective, @pragma_checksum {
 
   override string getAPrimaryQlClass() { result = "PragmaChecksumDirective" }
 }
+
+/**
+ * An `#define` directive.
+ */
+class DefineDirective extends PreprocessorDirective, @directive_define {
+  /** Gets the name of the preprocessor symbol that is being set by this directive. */
+  string getName() { directive_defines(this, result) }
+
+  override string toString() { result = "#define ..." }
+
+  override string getAPrimaryQlClass() { result = "DefineDirective" }
+}

csharp/ql/src/semmlecode.csharp.dbscheme

@@ -331,7 +331,11 @@ using_directive_location(
   unique int id: @using_directive ref,
   int loc: @location ref);
 
-@preprocessor_directive = @pragma_warning | @pragma_checksum;
+@preprocessor_directive = @pragma_warning | @pragma_checksum | @directive_define;
+
+directive_defines(
+  unique int id: @directive_define,
+  string name: string ref);
 
 pragma_checksums(
   unique int id: @pragma_checksum,

csharp/ql/test/library-tests/comments/DefineDirectives.expected

@@ -0,0 +1 @@
+| trivia.cs:4:1:4:13 | #define ... | DEBUG |

csharp/ql/test/library-tests/comments/DefineDirectives.ql

@@ -0,0 +1,4 @@
+import csharp
+
+from DefineDirective d
+select d, d.getName()