Extract undef directives

tamasvajk · tamasvajk · commit 3740aba4a800 · 2021-02-04T08:42:38.000+01:00
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/PreprocessorDirectives/UndefineDirective.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/PreprocessorDirectives/UndefineDirective.cs
@@ -0,0 +1,18 @@
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using System.IO;
+
+namespace Semmle.Extraction.CSharp.Entities
+{
+    internal class UndefineDirective : PreprocessorDirective<UndefDirectiveTriviaSyntax>
+    {
+        public UndefineDirective(Context cx, UndefDirectiveTriviaSyntax trivia)
+            : base(cx, trivia)
+        {
+        }
+
+        protected override void PopulatePreprocessor(TextWriter trapFile)
+        {
+            trapFile.directive_undefines(this, trivia.Name.ToString());
+        }
+    }
+}
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Populators/DirectiveVisitor.cs b/csharp/extractor/Semmle.Extraction.CSharp/Populators/DirectiveVisitor.cs
@@ -27,5 +27,10 @@ public override void VisitDefineDirectiveTrivia(DefineDirectiveTriviaSyntax node
         {
             new Entities.DefineDirective(cx, node);
         }
+
+        public override void VisitUndefDirectiveTrivia(UndefDirectiveTriviaSyntax node)
+        {
+            new Entities.UndefineDirective(cx, node);
+        }
     }
 }
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Tuples.cs b/csharp/extractor/Semmle.Extraction.CSharp/Tuples.cs
@@ -625,5 +625,10 @@ internal static void directive_defines(this TextWriter trapFile, DefineDirective
         {
             trapFile.WriteTuple("directive_defines", directive, name);
         }
+
+        internal static void directive_undefines(this TextWriter trapFile, UndefineDirective directive, string name)
+        {
+            trapFile.WriteTuple("directive_undefines", directive, name);
+        }
     }
 }
diff --git a/csharp/ql/src/semmle/code/csharp/Preprocessor.qll b/csharp/ql/src/semmle/code/csharp/Preprocessor.qll
@@ -58,3 +58,15 @@ class DefineDirective extends PreprocessorDirective, @directive_define {
 
   override string getAPrimaryQlClass() { result = "DefineDirective" }
 }
+
+/**
+ * An `#undef` directive.
+ */
+class UndefineDirective extends PreprocessorDirective, @directive_undefine {
+  /** Gets the name of the preprocessor symbol that is being unset by this directive. */
+  string getName() { directive_undefines(this, result) }
+
+  override string toString() { result = "#undef ..." }
+
+  override string getAPrimaryQlClass() { result = "UndefineDirective" }
+}
diff --git a/csharp/ql/src/semmlecode.csharp.dbscheme b/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 | @directive_define;
+@preprocessor_directive = @pragma_warning | @pragma_checksum | @directive_define | @directive_undefine;
+
+directive_undefines(
+  unique int id: @directive_undefine,
+  string name: string ref);
 
 directive_defines(
   unique int id: @directive_define,
diff --git a/csharp/ql/test/library-tests/comments/UndefineDirectives.expected b/csharp/ql/test/library-tests/comments/UndefineDirectives.expected
@@ -0,0 +1 @@
+| trivia.cs:6:1:6:12 | #undef ... | DEBUG |
diff --git a/csharp/ql/test/library-tests/comments/UndefineDirectives.ql b/csharp/ql/test/library-tests/comments/UndefineDirectives.ql
@@ -0,0 +1,4 @@
+import csharp
+
+from UndefineDirective d
+select d, d.getName()

Original file line number	Diff line number	Diff line change
`@@ -27,5 +27,10 @@ public override void VisitDefineDirectiveTrivia(DefineDirectiveTriviaSyntax node`
`27`	`27`	`{`
`28`	`28`	`new Entities.DefineDirective(cx, node);`
`29`	`29`	`}`
	`30`	`+`
	`31`	`+ public override void VisitUndefDirectiveTrivia(UndefDirectiveTriviaSyntax node)`
	`32`	`+ {`
	`33`	`+ new Entities.UndefineDirective(cx, node);`
	`34`	`+ }`
`30`	`35`	`}`
`31`	`36`	`}`
Original file line number	Diff line number	Diff line change
`@@ -625,5 +625,10 @@ internal static void directive_defines(this TextWriter trapFile, DefineDirective`
`625`	`625`	`{`
`626`	`626`	`trapFile.WriteTuple("directive_defines", directive, name);`
`627`	`627`	`}`
	`628`	`+`
	`629`	`+ internal static void directive_undefines(this TextWriter trapFile, UndefineDirective directive, string name)`
	`630`	`+ {`
	`631`	`+ trapFile.WriteTuple("directive_undefines", directive, name);`
	`632`	`+ }`
`628`	`633`	`}`
`629`	`634`	`}`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+\| trivia.cs:6:1:6:12 \| #undef ... \| DEBUG \|`