1 files changed, 97 insertions, 7 deletions

diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 2ce8fa9..8405b44 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -3288,6 +3288,19 @@ void Parser::ParseAlignmentSpecifier(ParsedAttributes &Attrs,
   }
 }
 
+void Parser::DistributeCLateParsedAttrs(Decl *Dcl,
+                                        LateParsedAttrList *LateAttrs) {
+  assert(Dcl && "Dcl cannot be null");
+
+  if (!LateAttrs)
+    return;
+
+  for (auto *LateAttr : *LateAttrs) {
+    if (LateAttr->Decls.empty())
+      LateAttr->addDecl(Dcl);
+  }
+}
+
 /// Bounds attributes (e.g., counted_by):
 ///   AttrName '(' expression ')'
 void Parser::ParseBoundsAttribute(IdentifierInfo &AttrName,
@@ -4825,13 +4838,14 @@ static void DiagnoseCountAttributedTypeInUnnamedAnon(ParsingDeclSpec &DS,
 ///
 void Parser::ParseStructDeclaration(
     ParsingDeclSpec &DS,
-    llvm::function_ref<void(ParsingFieldDeclarator &)> FieldsCallback) {
+    llvm::function_ref<Decl *(ParsingFieldDeclarator &)> FieldsCallback,
+    LateParsedAttrList *LateFieldAttrs) {
 
   if (Tok.is(tok::kw___extension__)) {
     // __extension__ silences extension warnings in the subexpression.
     ExtensionRAIIObject O(Diags);  // Use RAII to do this.
     ConsumeToken();
-    return ParseStructDeclaration(DS, FieldsCallback);
+    return ParseStructDeclaration(DS, FieldsCallback, LateFieldAttrs);
   }
 
   // Parse leading attributes.
@@ -4896,10 +4910,12 @@ void Parser::ParseStructDeclaration(
     }
 
     // If attributes exist after the declarator, parse them.
-    MaybeParseGNUAttributes(DeclaratorInfo.D);
+    MaybeParseGNUAttributes(DeclaratorInfo.D, LateFieldAttrs);
 
     // We're done with this declarator;  invoke the callback.
-    FieldsCallback(DeclaratorInfo);
+    Decl *Field = FieldsCallback(DeclaratorInfo);
+    if (Field)
+      DistributeCLateParsedAttrs(Field, LateFieldAttrs);
 
     // If we don't have a comma, it is either the end of the list (a ';')
     // or an error, bail out.
@@ -4910,6 +4926,69 @@ void Parser::ParseStructDeclaration(
   }
 }
 
+/// Finish parsing an attribute for which parsing was delayed.
+/// This will be called at the end of parsing a class declaration
+/// for each LateParsedAttribute. We consume the saved tokens and
+/// create an attribute with the arguments filled in. We add this
+/// to the Attribute list for the decl.
+void Parser::ParseLexedCAttribute(LateParsedAttribute &LA,
+                                  ParsedAttributes *OutAttrs) {
+  // Create a fake EOF so that attribute parsing won't go off the end of the
+  // attribute.
+  Token AttrEnd;
+  AttrEnd.startToken();
+  AttrEnd.setKind(tok::eof);
+  AttrEnd.setLocation(Tok.getLocation());
+  AttrEnd.setEofData(LA.Toks.data());
+  LA.Toks.push_back(AttrEnd);
+
+  // Append the current token at the end of the new token stream so that it
+  // doesn't get lost.
+  LA.Toks.push_back(Tok);
+  PP.EnterTokenStream(LA.Toks, /*DisableMacroExpansion=*/true,
+                      /*IsReinject=*/true);
+  // Drop the current token and bring the first cached one. It's the same token
+  // as when we entered this function.
+  ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
+
+  ParsedAttributes Attrs(AttrFactory);
+
+  assert(LA.Decls.size() <= 1 &&
+         "late field attribute expects to have at most one declaration.");
+
+  // Dispatch based on the attribute and parse it
+  const AttributeCommonInfo::Form ParsedForm = ParsedAttr::Form::GNU();
+  IdentifierInfo *ScopeName = nullptr;
+  const ParsedAttr::Kind AttrKind =
+      ParsedAttr::getParsedKind(&LA.AttrName, /*ScopeName=*/ScopeName,
+                                /*SyntaxUsed=*/ParsedForm.getSyntax());
+  switch (AttrKind) {
+  case ParsedAttr::Kind::AT_CountedBy:
+    ParseBoundsAttribute(LA.AttrName, LA.AttrNameLoc, Attrs,
+                         /*ScopeName=*/ScopeName, SourceLocation(),
+                         /*Form=*/ParsedForm);
+    break;
+  default:
+    llvm_unreachable("Unhandled late parsed attribute");
+  }
+
+  for (auto *D : LA.Decls)
+    Actions.ActOnFinishDelayedAttribute(getCurScope(), D, Attrs);
+
+  // Due to a parsing error, we either went over the cached tokens or
+  // there are still cached tokens left, so we skip the leftover tokens.
+  while (Tok.isNot(tok::eof))
+    ConsumeAnyToken();
+
+  // Consume the fake EOF token if it's there
+  if (Tok.is(tok::eof) && Tok.getEofData() == AttrEnd.getEofData())
+    ConsumeAnyToken();
+
+  if (OutAttrs) {
+    OutAttrs->takeAllFrom(Attrs);
+  }
+}
+
 /// ParseStructUnionBody
 ///       struct-contents:
 ///         struct-declaration-list
@@ -4933,6 +5012,11 @@ void Parser::ParseStructUnionBody(SourceLocation RecordLoc,
   ParseScope StructScope(this, Scope::ClassScope|Scope::DeclScope);
   Actions.ActOnTagStartDefinition(getCurScope(), TagDecl);
 
+  // `LateAttrParseExperimentalExtOnly=true` requests that only attributes
+  // marked with `LateAttrParseExperimentalExt` are late parsed.
+  LateParsedAttrList LateFieldAttrs(/*PSoon=*/false,
+                                    /*LateAttrParseExperimentalExtOnly=*/true);
+
   // While we still have something to read, read the declarations in the struct.
   while (!tryParseMisplacedModuleImport() && Tok.isNot(tok::r_brace) &&
          Tok.isNot(tok::eof)) {
@@ -4983,18 +5067,19 @@ void Parser::ParseStructUnionBody(SourceLocation RecordLoc,
     }
 
     if (!Tok.is(tok::at)) {
-      auto CFieldCallback = [&](ParsingFieldDeclarator &FD) {
+      auto CFieldCallback = [&](ParsingFieldDeclarator &FD) -> Decl * {
         // Install the declarator into the current TagDecl.
         Decl *Field =
             Actions.ActOnField(getCurScope(), TagDecl,
                                FD.D.getDeclSpec().getSourceRange().getBegin(),
                                FD.D, FD.BitfieldSize);
         FD.complete(Field);
+        return Field;
       };
 
       // Parse all the comma separated declarators.
       ParsingDeclSpec DS(*this);
-      ParseStructDeclaration(DS, CFieldCallback);
+      ParseStructDeclaration(DS, CFieldCallback, &LateFieldAttrs);
     } else { // Handle @defs
       ConsumeToken();
       if (!Tok.isObjCAtKeyword(tok::objc_defs)) {
@@ -5035,7 +5120,12 @@ void Parser::ParseStructUnionBody(SourceLocation RecordLoc,
 
   ParsedAttributes attrs(AttrFactory);
   // If attributes exist after struct contents, parse them.
-  MaybeParseGNUAttributes(attrs);
+  MaybeParseGNUAttributes(attrs, &LateFieldAttrs);
+
+  // Late parse field attributes if necessary.
+  assert(!getLangOpts().CPlusPlus);
+  for (auto *LateAttr : LateFieldAttrs)
+    ParseLexedCAttribute(*LateAttr);
 
   SmallVector<Decl *, 32> FieldDecls(TagDecl->fields());