[PATCH] D92141: Fix noderef for AddrOf on MemberExpr

[Jann Horn via Phabricator via cfe-commits]

thejh updated this revision to Diff 307728.
thejh added a comment.

Removed duplicate tests as suggested by leonardchan


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D92141/new/

https://reviews.llvm.org/D92141

Files:
  clang/lib/Sema/SemaExprMember.cpp
  clang/test/Frontend/noderef.c


Index: clang/test/Frontend/noderef.c
===================================================================
--- clang/test/Frontend/noderef.c
+++ clang/test/Frontend/noderef.c
@@ -70,6 +70,12 @@
   x = sizeof(s->a + (s->b)); // ok
   x = sizeof(int[++s->a]);   // expected-warning{{dereferencing s; was declared with a 'noderef' type}}
 
+  // Struct member access should carry NoDeref type information through to an
+  // enclosing AddrOf.
+  p2 = &s->a;   // expected-warning{{casting to dereferenceable pointer removes 'noderef' attribute}}
+  p2 = &(*s).a; // expected-warning{{casting to dereferenceable pointer removes 'noderef' attribute}}
+  x = *&s->a;   // expected-warning{{dereferencing expression marked as 'noderef'}}
+
   // Nested struct access
   struct S2 NODEREF *s2_noderef;    // expected-note 5 {{s2_noderef declared here}}
   p = s2_noderef->a;  // ok since result is an array in a struct
@@ -113,7 +119,7 @@
 
   p = s2_arr[1]->a;
   p = s2_arr[1]->b; // expected-warning{{dereferencing expression marked as 'noderef'}}
-  int **bptr = &s2_arr[1]->b;
+  int *NODEREF *bptr = &s2_arr[1]->b;
 
   x = s2->s2->a;        // expected-warning{{dereferencing expression marked as 'noderef'}}
   x = s2_noderef->a[1]; // expected-warning{{dereferencing s2_noderef; was declared with a 'noderef' type}}
Index: clang/lib/Sema/SemaExprMember.cpp
===================================================================
--- clang/lib/Sema/SemaExprMember.cpp
+++ clang/lib/Sema/SemaExprMember.cpp
@@ -1810,6 +1810,14 @@
     Qualifiers Combined = BaseQuals + MemberQuals;
     if (Combined != MemberQuals)
       MemberType = Context.getQualifiedType(MemberType, Combined);
+
+    // Pick up NoDeref from the base in case we end up using AddrOf on the
+    // result. E.g. the expression
+    //     &someNoDerefPtr->pointerMember
+    // should be a noderef pointer again.
+    if (BaseType->hasAttr(attr::NoDeref))
+      MemberType =
+          Context.getAttributedType(attr::NoDeref, MemberType, MemberType);
   }
 
   auto *CurMethod = dyn_cast<CXXMethodDecl>(CurContext);


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