[PATCH] D157201: [Clang] Support qualified name as member designator in offsetof

[Yichi Lee via Phabricator via cfe-commits]

yichi170 updated this revision to Diff 547703.
yichi170 added a comment.

updated ReleaseNotes and applied suggestions. The related issue #63443 <https://github.com/llvm/llvm-project/issues/63443> is still not fixed.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D157201/new/

https://reviews.llvm.org/D157201

Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Sema/Sema.h
  clang/lib/Parse/ParseExpr.cpp
  clang/lib/Sema/SemaExpr.cpp
  clang/test/Sema/offsetof.c


Index: clang/test/Sema/offsetof.c
===================================================================
--- clang/test/Sema/offsetof.c
+++ clang/test/Sema/offsetof.c
@@ -73,3 +73,8 @@
   return __builtin_offsetof(Array, array[*(int*)0]); // expected-warning{{indirection of non-volatile null pointer}} expected-note{{__builtin_trap}}
 }
 
+// https://github.com/llvm/llvm-project/issues/64154
+struct X2 { int a; };
+int x2[__builtin_offsetof(struct X2, X2::a) == 0 ? 1 : -1];
+int x3[__builtin_offsetof(struct X2, X2::X2) == 0 ? 1 : -1]; // expected-error{{no member named 'X2'}}
+
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -16663,6 +16663,9 @@
                        << CurrentType);
     RecordDecl *RD = RC->getDecl();
 
+    if (OC.isQualifier && RD->getIdentifier() == OC.U.IdentInfo)
+      continue;
+
     // C++ [lib.support.types]p5:
     //   The macro offsetof accepts a restricted set of type arguments in this
     //   International Standard. type shall be a POD structure or a POD union
Index: clang/lib/Parse/ParseExpr.cpp
===================================================================
--- clang/lib/Parse/ParseExpr.cpp
+++ clang/lib/Parse/ParseExpr.cpp
@@ -2641,10 +2641,13 @@
 
     // FIXME: This loop leaks the index expressions on error.
     while (true) {
-      if (Tok.is(tok::period)) {
+      if (Tok.is(tok::period) || Tok.is(tok::coloncolon)) {
         // offsetof-member-designator: offsetof-member-designator '.' identifier
+        if (Tok.is(tok::coloncolon))
+          Comps.back().isQualifier = true;
         Comps.push_back(Sema::OffsetOfComponent());
         Comps.back().isBrackets = false;
+        Comps.back().isQualifier = false;
         Comps.back().LocStart = ConsumeToken();
 
         if (Tok.isNot(tok::identifier)) {
@@ -2661,6 +2664,7 @@
         // offsetof-member-designator: offsetof-member-design '[' expression ']'
         Comps.push_back(Sema::OffsetOfComponent());
         Comps.back().isBrackets = true;
+        Comps.back().isQualifier = false;
         BalancedDelimiterTracker ST(*this, tok::l_square);
         ST.consumeOpen();
         Comps.back().LocStart = ST.getOpenLocation();
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -6036,6 +6036,7 @@
   struct OffsetOfComponent {
     SourceLocation LocStart, LocEnd;
     bool isBrackets;  // true if [expr], false if .ident
+    bool isQualifier;
     union {
       IdentifierInfo *IdentInfo;
       Expr *E;
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -56,6 +56,7 @@
 
 C++ Language Changes
 --------------------
+- Improved `__builtin_offsetof` support, allowing qualified name in member designator.
 
 C++20 Feature Support
 ^^^^^^^^^^^^^^^^^^^^^


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