[PATCH] D151732: [clang][docs] document __attribute__((cleanup())) GNU C extension

[Nick Desaulniers via Phabricator via cfe-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG8dc13957cb17: [clang][docs] document __attribute__((cleanup())) GNU C extension (authored by nickdesaulniers).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D151732/new/

https://reviews.llvm.org/D151732

Files:
  clang/include/clang/Basic/Attr.td
  clang/include/clang/Basic/AttrDocs.td


Index: clang/include/clang/Basic/AttrDocs.td
===================================================================
--- clang/include/clang/Basic/AttrDocs.td
+++ clang/include/clang/Basic/AttrDocs.td
@@ -7023,3 +7023,30 @@
 its underlying representation to be a WebAssembly ``funcref``.
   }];
 }
+
+def CleanupDocs : Documentation {
+  let Category = DocCatType;
+  let Content = [{
+This attribute allows a function to be run when a local variable goes out of
+scope. The attribute takes the identifier of a function with a parameter type
+that is a pointer to the type with the attribute.
+
+.. code-block:: c
+
+  static void foo (int *) { ... }
+  static void bar (int *) { ... }
+  void baz (void) {
+    int x __attribute__((cleanup(foo)));
+    {
+      int y __attribute__((cleanup(bar)));
+    }
+  }
+
+The above example will result in a call to ``bar`` being passed the address of
+`y`` when ``y`` goes out of scope, then a call to ``foo`` being passed the
+address of ``x`` when ``x`` goes out of scope. If two or more variables share
+the same scope, their ``cleanup`` callbacks are invoked in the reverse order
+the variables were declared in. It is not possible to check the return value
+(if any) of these ``cleanup`` callback functions.
+}];
+}
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -1097,7 +1097,7 @@
   let Spellings = [GCC<"cleanup">];
   let Args = [DeclArgument<Function, "FunctionDecl">];
   let Subjects = SubjectList<[LocalVar]>;
-  let Documentation = [Undocumented];
+  let Documentation = [CleanupDocs];
 }
 
 def CmseNSEntry : InheritableAttr, TargetSpecificAttr<TargetARM> {


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