From 5ef4fe7d8ee31c83c4ebc118b21402e7ea14c9f2 Mon Sep 17 00:00:00 2001
From: David Majnemer <david.majnemer@gmail.com>
Date: Fri, 13 Jun 2014 06:43:46 +0000
Subject: MS ABI: Fix inheritance model calculation in CRTP

CRTP-like patterns involve a class which inherits from another class
using itself as a template parameter.

However, the base class itself may try to create a pointer-to-member
which involves the derived class.  This is problematic because we
may not have finished parsing the most derived classes' base specifiers
yet.

It turns out that MSVC simply uses the unspecified inheritance model
instead of doing anything fancy.

This fixes PR19987.

llvm-svn: 210886
---
 clang/lib/AST/DeclCXX.cpp         | 9 +++++++--
 clang/lib/AST/MicrosoftCXXABI.cpp | 2 +-
 clang/lib/Sema/SemaDeclCXX.cpp    | 3 +++
 3 files changed, 11 insertions(+), 3 deletions(-)

(limited to 'clang/lib')

diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index 0ac8b73e306..43d0fca9f92 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -70,7 +70,8 @@ CXXRecordDecl::DefinitionData::DefinitionData(CXXRecordDecl *D)
     ImplicitCopyAssignmentHasConstParam(true),
     HasDeclaredCopyConstructorWithConstParam(false),
     HasDeclaredCopyAssignmentWithConstParam(false),
-    IsLambda(false), NumBases(0), NumVBases(0), Bases(), VBases(),
+    IsLambda(false), IsParsingBaseSpecifiers(false), NumBases(0), NumVBases(0),
+    Bases(), VBases(),
     Definition(D), FirstFriend() {
 }
 
@@ -334,8 +335,10 @@ CXXRecordDecl::setBases(CXXBaseSpecifier const * const *Bases,
     addedClassSubobject(BaseClassDecl);
   }
   
-  if (VBases.empty())
+  if (VBases.empty()) {
+    data().IsParsingBaseSpecifiers = false;
     return;
+  }
 
   // Create base specifier for any direct or indirect virtual bases.
   data().VBases = new (C) CXXBaseSpecifier[VBases.size()];
@@ -346,6 +349,8 @@ CXXRecordDecl::setBases(CXXBaseSpecifier const * const *Bases,
       addedClassSubobject(Type->getAsCXXRecordDecl());
     data().getVBases()[I] = *VBases[I];
   }
+
+  data().IsParsingBaseSpecifiers = false;
 }
 
 void CXXRecordDecl::addedClassSubobject(CXXRecordDecl *Subobj) {
diff --git a/clang/lib/AST/MicrosoftCXXABI.cpp b/clang/lib/AST/MicrosoftCXXABI.cpp
index 359e8648278..6870315b216 100644
--- a/clang/lib/AST/MicrosoftCXXABI.cpp
+++ b/clang/lib/AST/MicrosoftCXXABI.cpp
@@ -93,7 +93,7 @@ static bool usesMultipleInheritanceModel(const CXXRecordDecl *RD) {
 }
 
 MSInheritanceAttr::Spelling CXXRecordDecl::calculateInheritanceModel() const {
-  if (!hasDefinition())
+  if (!hasDefinition() || isParsingBaseSpecifiers())
     return MSInheritanceAttr::Keyword_unspecified_inheritance;
   if (getNumVBases() > 0)
     return MSInheritanceAttr::Keyword_virtual_inheritance;
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 57e6550cec5..ed7908dfc92 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -1431,6 +1431,9 @@ Sema::ActOnBaseSpecifier(Decl *classdecl, SourceRange SpecifierRange,
   if (!Class)
     return true;
 
+  // We haven't yet attached the base specifiers.
+  Class->setIsParsingBaseSpecifiers();
+
   // We do not support any C++11 attributes on base-specifiers yet.
   // Diagnose any attributes we see.
   if (!Attributes.empty()) {
-- 
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