[AST] Fix a crash on invalid bitwidth exprs when preserving the recoveryexprs.

Summary:
If the bitwith expr contains errors, we mark the field decl invalid.

This patch also tweaks the behavior of ObjCInterfaceDecl to be consistent with
existing RecordDecl -- getObjCLayout method is only called with valid decls.

Reviewers: sammccall

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76953
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 19f67fc..461b155 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -2161,6 +2161,11 @@
     return getTypeInfo(cast<AdjustedType>(T)->getAdjustedType().getTypePtr());
   case Type::ObjCInterface: {
     const auto *ObjCI = cast<ObjCInterfaceType>(T);
+    if (ObjCI->getDecl()->isInvalidDecl()) {
+      Width = 8;
+      Align = 8;
+      break;
+    }
     const ASTRecordLayout &Layout = getASTObjCInterfaceLayout(ObjCI->getDecl());
     Width = toBits(Layout.getSize());
     Align = toBits(Layout.getAlignment());
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index 9a21732..028e82a 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -3222,7 +3222,8 @@
   if (D->hasExternalLexicalStorage() && !D->getDefinition())
     getExternalSource()->CompleteType(const_cast<ObjCInterfaceDecl*>(D));
   D = D->getDefinition();
-  assert(D && D->isThisDeclarationADefinition() && "Invalid interface decl!");
+  assert(D && !D->isInvalidDecl() && D->isThisDeclarationADefinition() &&
+         "Invalid interface decl!");
 
   // Look up this layout, if already laid out, return what we have.
   const ObjCContainerDecl *Key =
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 9319f4e..ea3a0c2 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -16172,6 +16172,10 @@
                                 IdentifierInfo *FieldName,
                                 QualType FieldTy, bool IsMsStruct,
                                 Expr *BitWidth, bool *ZeroWidth) {
+  assert(BitWidth);
+  if (BitWidth->containsErrors())
+    return ExprError();
+
   // Default to true; that shouldn't confuse checks for emptiness
   if (ZeroWidth)
     *ZeroWidth = true;