Index: cfe/trunk/include/clang/AST/DeclBase.h
===================================================================
--- cfe/trunk/include/clang/AST/DeclBase.h
+++ cfe/trunk/include/clang/AST/DeclBase.h
@@ -70,8 +70,15 @@
 /// Decl - This represents one declaration (or definition), e.g. a variable,
 /// typedef, function, struct, etc.
 ///
+/// Note: There are objects tacked on before the *beginning* of Decl
+/// (and its subclasses) in its Decl::operator new(). Proper alignment
+/// of all subclasses (not requiring more than DeclObjAlignment) is
+/// asserted in DeclBase.cpp.
 class Decl {
 public:
+  /// \brief Alignment guaranteed when allocating Decl and any subtypes.
+  enum { DeclObjAlignment = llvm::AlignOf<uint64_t>::Alignment };
+
   /// \brief Lists the kind of concrete classes of Decl.
   enum Kind {
 #define DECL(DERIVED, BASE) DERIVED,
Index: cfe/trunk/include/clang/AST/DeclTemplate.h
===================================================================
--- cfe/trunk/include/clang/AST/DeclTemplate.h
+++ cfe/trunk/include/clang/AST/DeclTemplate.h
@@ -43,7 +43,7 @@
 
 /// \brief Stores a list of template parameters for a TemplateDecl and its
 /// derived classes.
-class TemplateParameterList {
+class LLVM_ALIGNAS(/*alignof(void*)*/ LLVM_PTR_SIZE) TemplateParameterList {
   /// The location of the 'template' keyword.
   SourceLocation TemplateLoc;
 
@@ -542,27 +542,20 @@
 ///     friend void foo<>(T);
 ///   };
 /// \endcode
-class DependentFunctionTemplateSpecializationInfo {
-  struct CA {
-    /// The number of potential template candidates.
-    unsigned NumTemplates;
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8)
+    DependentFunctionTemplateSpecializationInfo {
+  /// The number of potential template candidates.
+  unsigned NumTemplates;
 
-    /// The number of template arguments.
-    unsigned NumArgs;
-  };
-
-  union {
-    // Force sizeof to be a multiple of sizeof(void*) so that the
-    // trailing data is aligned.
-    void *Aligner;
-    struct CA d;
-  };
+  /// The number of template arguments.
+  unsigned NumArgs;
 
   /// The locations of the left and right angle brackets.
   SourceRange AngleLocs;
 
   FunctionTemplateDecl * const *getTemplates() const {
-    return reinterpret_cast<FunctionTemplateDecl*const*>(this+1);
+    return reinterpret_cast<FunctionTemplateDecl *const *>(
+        &getTemplateArgs()[NumArgs]);
   }
 
 public:
@@ -572,9 +565,7 @@
 
   /// \brief Returns the number of function templates that this might
   /// be a specialization of.
-  unsigned getNumTemplates() const {
-    return d.NumTemplates;
-  }
+  unsigned getNumTemplates() const { return NumTemplates; }
 
   /// \brief Returns the i'th template candidate.
   FunctionTemplateDecl *getTemplate(unsigned I) const {
@@ -584,14 +575,11 @@
 
   /// \brief Returns the explicit template arguments that were given.
   const TemplateArgumentLoc *getTemplateArgs() const {
-    return reinterpret_cast<const TemplateArgumentLoc*>(
-                                            &getTemplates()[getNumTemplates()]);
+    return reinterpret_cast<const TemplateArgumentLoc *>(this + 1);
   }
 
   /// \brief Returns the number of explicit template arguments that were given.
-  unsigned getNumTemplateArgs() const {
-    return d.NumArgs;
-  }
+  unsigned getNumTemplateArgs() const { return NumArgs; }
 
   /// \brief Returns the nth template argument.
   const TemplateArgumentLoc &getTemplateArg(unsigned I) const {
Index: cfe/trunk/include/clang/AST/EvaluatedExprVisitor.h
===================================================================
--- cfe/trunk/include/clang/AST/EvaluatedExprVisitor.h
+++ cfe/trunk/include/clang/AST/EvaluatedExprVisitor.h
@@ -88,8 +88,8 @@
 
   void VisitLambdaExpr(PTR(LambdaExpr) LE) {
     // Only visit the capture initializers, and not the body.
-    for (LambdaExpr::capture_init_iterator I = LE->capture_init_begin(),
-                                           E = LE->capture_init_end();
+    for (LambdaExpr::const_capture_init_iterator I = LE->capture_init_begin(),
+                                                 E = LE->capture_init_end();
          I != E; ++I)
       if (*I)
         this->Visit(*I);
Index: cfe/trunk/include/clang/AST/Expr.h
===================================================================
--- cfe/trunk/include/clang/AST/Expr.h
+++ cfe/trunk/include/clang/AST/Expr.h
@@ -897,7 +897,7 @@
 ///   DeclRefExprBits.RefersToEnclosingVariableOrCapture
 ///       Specifies when this declaration reference expression (validly)
 ///       refers to an enclosed local or a captured variable.
-class DeclRefExpr : public Expr {
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) DeclRefExpr : public Expr {
   /// \brief The declaration that we are referencing.
   ValueDecl *D;
 
@@ -1051,13 +1051,17 @@
     if (!hasTemplateKWAndArgsInfo())
       return nullptr;
 
-    if (hasFoundDecl())
+    if (hasFoundDecl()) {
       return reinterpret_cast<ASTTemplateKWAndArgsInfo *>(
-        &getInternalFoundDecl() + 1);
+          llvm::alignAddr(&getInternalFoundDecl() + 1,
+                          llvm::alignOf<ASTTemplateKWAndArgsInfo>()));
+    }
 
-    if (hasQualifier())
+    if (hasQualifier()) {
       return reinterpret_cast<ASTTemplateKWAndArgsInfo *>(
-        &getInternalQualifierLoc() + 1);
+          llvm::alignAddr(&getInternalQualifierLoc() + 1,
+                          llvm::alignOf<ASTTemplateKWAndArgsInfo>()));
+    }
 
     return reinterpret_cast<ASTTemplateKWAndArgsInfo *>(this + 1);
   }
@@ -2301,9 +2305,9 @@
 
 /// MemberExpr - [C99 6.5.2.3] Structure and Union Members.  X->F and X.F.
 ///
-class MemberExpr : public Expr {
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) MemberExpr : public Expr {
   /// Extra data stored in some member expressions.
-  struct MemberNameQualifier {
+  struct LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) MemberNameQualifier {
     /// \brief The nested-name-specifier that qualifies the name, including
     /// source-location information.
     NestedNameSpecifierLoc QualifierLoc;
Index: cfe/trunk/include/clang/AST/ExprCXX.h
===================================================================
--- cfe/trunk/include/clang/AST/ExprCXX.h
+++ cfe/trunk/include/clang/AST/ExprCXX.h
@@ -1401,25 +1401,39 @@
       ExplicitResultType(false), HasArrayIndexVars(true) { 
     getStoredStmts()[NumCaptures] = nullptr;
   }
-  
-  Stmt **getStoredStmts() const {
-    return reinterpret_cast<Stmt **>(const_cast<LambdaExpr *>(this) + 1);
+
+  Stmt **getStoredStmts() { return reinterpret_cast<Stmt **>(this + 1); }
+
+  Stmt *const *getStoredStmts() const {
+    return reinterpret_cast<Stmt *const *>(this + 1);
   }
-  
+
   /// \brief Retrieve the mapping from captures to the first array index
   /// variable.
-  unsigned *getArrayIndexStarts() const {
+  unsigned *getArrayIndexStarts() {
     return reinterpret_cast<unsigned *>(getStoredStmts() + NumCaptures + 1);
   }
 
+  const unsigned *getArrayIndexStarts() const {
+    return reinterpret_cast<const unsigned *>(getStoredStmts() + NumCaptures +
+                                              1);
+  }
+
   /// \brief Retrieve the complete set of array-index variables.
-  VarDecl **getArrayIndexVars() const {
+  VarDecl **getArrayIndexVars() {
     unsigned ArrayIndexSize = llvm::RoundUpToAlignment(
         sizeof(unsigned) * (NumCaptures + 1), llvm::alignOf<VarDecl *>());
     return reinterpret_cast<VarDecl **>(
         reinterpret_cast<char *>(getArrayIndexStarts()) + ArrayIndexSize);
   }
 
+  VarDecl *const *getArrayIndexVars() const {
+    unsigned ArrayIndexSize = llvm::RoundUpToAlignment(
+        sizeof(unsigned) * (NumCaptures + 1), llvm::alignOf<VarDecl *>());
+    return reinterpret_cast<VarDecl *const *>(
+        reinterpret_cast<const char *>(getArrayIndexStarts()) + ArrayIndexSize);
+  }
+
 public:
   /// \brief Construct a new lambda expression.
   static LambdaExpr *Create(const ASTContext &C,
@@ -1501,31 +1515,54 @@
   /// arguments.
   typedef Expr **capture_init_iterator;
 
+  /// \brief Const iterator that walks over the capture initialization
+  /// arguments.
+  typedef Expr *const *const_capture_init_iterator;
+
   /// \brief Retrieve the initialization expressions for this lambda's captures.
-  llvm::iterator_range<capture_init_iterator> capture_inits() const {
+  llvm::iterator_range<capture_init_iterator> capture_inits() {
     return llvm::iterator_range<capture_init_iterator>(capture_init_begin(),
                                                        capture_init_end());
   }
 
+  /// \brief Retrieve the initialization expressions for this lambda's captures.
+  llvm::iterator_range<const_capture_init_iterator> capture_inits() const {
+    return llvm::iterator_range<const_capture_init_iterator>(
+        capture_init_begin(), capture_init_end());
+  }
+
   /// \brief Retrieve the first initialization argument for this
   /// lambda expression (which initializes the first capture field).
-  capture_init_iterator capture_init_begin() const {
+  capture_init_iterator capture_init_begin() {
     return reinterpret_cast<Expr **>(getStoredStmts());
   }
 
+  /// \brief Retrieve the first initialization argument for this
+  /// lambda expression (which initializes the first capture field).
+  const_capture_init_iterator capture_init_begin() const {
+    return reinterpret_cast<Expr *const *>(getStoredStmts());
+  }
+
   /// \brief Retrieve the iterator pointing one past the last
   /// initialization argument for this lambda expression.
-  capture_init_iterator capture_init_end() const {
-    return capture_init_begin() + NumCaptures;    
+  capture_init_iterator capture_init_end() {
+    return capture_init_begin() + NumCaptures;
   }
 
-  /// \brief Retrieve the set of index variables used in the capture 
+  /// \brief Retrieve the iterator pointing one past the last
+  /// initialization argument for this lambda expression.
+  const_capture_init_iterator capture_init_end() const {
+    return capture_init_begin() + NumCaptures;
+  }
+
+  /// \brief Retrieve the set of index variables used in the capture
   /// initializer of an array captured by copy.
   ///
-  /// \param Iter The iterator that points at the capture initializer for 
+  /// \param Iter The iterator that points at the capture initializer for
   /// which we are extracting the corresponding index variables.
-  ArrayRef<VarDecl *> getCaptureInitIndexVars(capture_init_iterator Iter) const;
-  
+  ArrayRef<VarDecl *>
+  getCaptureInitIndexVars(const_capture_init_iterator Iter) const;
+
   /// \brief Retrieve the source range covering the lambda introducer,
   /// which contains the explicit capture list surrounded by square
   /// brackets ([...]).
@@ -2302,7 +2339,7 @@
 
 /// \brief A reference to an overloaded function set, either an
 /// \c UnresolvedLookupExpr or an \c UnresolvedMemberExpr.
-class OverloadExpr : public Expr {
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) OverloadExpr : public Expr {
   /// \brief The common name of these declarations.
   DeclarationNameInfo NameInfo;
 
@@ -2606,7 +2643,8 @@
 /// qualifier (X<T>::) and the name of the entity being referenced
 /// ("value"). Such expressions will instantiate to a DeclRefExpr once the
 /// declaration can be found.
-class DependentScopeDeclRefExpr : public Expr {
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) DependentScopeDeclRefExpr
+    : public Expr {
   /// \brief The nested-name-specifier that qualifies this unresolved
   /// declaration name.
   NestedNameSpecifierLoc QualifierLoc;
@@ -2951,7 +2989,8 @@
 /// Like UnresolvedMemberExprs, these can be either implicit or
 /// explicit accesses.  It is only possible to get one of these with
 /// an implicit access if a qualifier is provided.
-class CXXDependentScopeMemberExpr : public Expr {
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) CXXDependentScopeMemberExpr
+    : public Expr {
   /// \brief The expression for the base pointer or class reference,
   /// e.g., the \c x in x.f.  Can be null in implicit accesses.
   Stmt *Base;
@@ -3206,7 +3245,8 @@
 /// In the final AST, an explicit access always becomes a MemberExpr.
 /// An implicit access may become either a MemberExpr or a
 /// DeclRefExpr, depending on whether the member is static.
-class UnresolvedMemberExpr : public OverloadExpr {
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) UnresolvedMemberExpr
+    : public OverloadExpr {
   /// \brief Whether this member expression used the '->' operator or
   /// the '.' operator.
   bool IsArrow : 1;
@@ -3330,6 +3370,17 @@
   }
 };
 
+inline ASTTemplateKWAndArgsInfo *OverloadExpr::getTemplateKWAndArgsInfo() {
+  if (!HasTemplateKWAndArgsInfo)
+    return nullptr;
+  if (isa<UnresolvedLookupExpr>(this))
+    return reinterpret_cast<ASTTemplateKWAndArgsInfo *>(
+        cast<UnresolvedLookupExpr>(this) + 1);
+  else
+    return reinterpret_cast<ASTTemplateKWAndArgsInfo *>(
+        cast<UnresolvedMemberExpr>(this) + 1);
+}
+
 /// \brief Represents a C++11 noexcept expression (C++ [expr.unary.noexcept]).
 ///
 /// The noexcept expression tests whether a given expression might throw. Its
@@ -3451,15 +3502,6 @@
   }
 };
 
-inline ASTTemplateKWAndArgsInfo *OverloadExpr::getTemplateKWAndArgsInfo() {
-  if (!HasTemplateKWAndArgsInfo) return nullptr;
-  if (isa<UnresolvedLookupExpr>(this))
-    return reinterpret_cast<ASTTemplateKWAndArgsInfo*>
-      (cast<UnresolvedLookupExpr>(this) + 1);
-  else
-    return reinterpret_cast<ASTTemplateKWAndArgsInfo*>
-      (cast<UnresolvedMemberExpr>(this) + 1);
-}
 
 /// \brief Represents an expression that computes the length of a parameter
 /// pack.
Index: cfe/trunk/include/clang/AST/ExprObjC.h
===================================================================
--- cfe/trunk/include/clang/AST/ExprObjC.h
+++ cfe/trunk/include/clang/AST/ExprObjC.h
@@ -341,6 +341,8 @@
   child_range children() { 
     // Note: we're taking advantage of the layout of the KeyValuePair struct
     // here. If that struct changes, this code will need to change as well.
+    static_assert(sizeof(KeyValuePair) == sizeof(Stmt *) * 2,
+                  "KeyValuePair is expected size");
     return child_range(reinterpret_cast<Stmt **>(this + 1),
                        reinterpret_cast<Stmt **>(this + 1) + NumElements * 2);
   }
Index: cfe/trunk/include/clang/AST/Stmt.h
===================================================================
--- cfe/trunk/include/clang/AST/Stmt.h
+++ cfe/trunk/include/clang/AST/Stmt.h
@@ -2076,8 +2076,10 @@
   /// \brief Construct an empty captured statement.
   CapturedStmt(EmptyShell Empty, unsigned NumCaptures);
 
-  Stmt **getStoredStmts() const {
-    return reinterpret_cast<Stmt **>(const_cast<CapturedStmt *>(this) + 1);
+  Stmt **getStoredStmts() { return reinterpret_cast<Stmt **>(this + 1); }
+
+  Stmt *const *getStoredStmts() const {
+    return reinterpret_cast<Stmt *const *>(this + 1);
   }
 
   Capture *getStoredCaptures() const;
@@ -2096,14 +2098,12 @@
 
   /// \brief Retrieve the statement being captured.
   Stmt *getCapturedStmt() { return getStoredStmts()[NumCaptures]; }
-  const Stmt *getCapturedStmt() const {
-    return const_cast<CapturedStmt *>(this)->getCapturedStmt();
-  }
+  const Stmt *getCapturedStmt() const { return getStoredStmts()[NumCaptures]; }
 
   /// \brief Retrieve the outlined function declaration.
   CapturedDecl *getCapturedDecl() { return CapDeclAndKind.getPointer(); }
   const CapturedDecl *getCapturedDecl() const {
-    return const_cast<CapturedStmt *>(this)->getCapturedDecl();
+    return CapDeclAndKind.getPointer();
   }
 
   /// \brief Set the outlined function declaration.
@@ -2164,18 +2164,36 @@
   typedef Expr **capture_init_iterator;
   typedef llvm::iterator_range<capture_init_iterator> capture_init_range;
 
-  capture_init_range capture_inits() const {
+  /// \brief Const iterator that walks over the capture initialization
+  /// arguments.
+  typedef Expr *const *const_capture_init_iterator;
+  typedef llvm::iterator_range<const_capture_init_iterator>
+      const_capture_init_range;
+
+  capture_init_range capture_inits() {
     return capture_init_range(capture_init_begin(), capture_init_end());
   }
 
+  const_capture_init_range capture_inits() const {
+    return const_capture_init_range(capture_init_begin(), capture_init_end());
+  }
+
   /// \brief Retrieve the first initialization argument.
-  capture_init_iterator capture_init_begin() const {
+  capture_init_iterator capture_init_begin() {
     return reinterpret_cast<Expr **>(getStoredStmts());
   }
 
+  const_capture_init_iterator capture_init_begin() const {
+    return reinterpret_cast<Expr *const *>(getStoredStmts());
+  }
+
   /// \brief Retrieve the iterator pointing one past the last initialization
   /// argument.
-  capture_init_iterator capture_init_end() const {
+  capture_init_iterator capture_init_end() {
+    return capture_init_begin() + NumCaptures;
+  }
+
+  const_capture_init_iterator capture_init_end() const {
     return capture_init_begin() + NumCaptures;
   }
 
Index: cfe/trunk/include/clang/AST/Type.h
===================================================================
--- cfe/trunk/include/clang/AST/Type.h
+++ cfe/trunk/include/clang/AST/Type.h
@@ -3118,11 +3118,13 @@
     assert(hasAnyConsumedParams());
 
     // Find the end of the exceptions.
-    Expr *const *eh_end = reinterpret_cast<Expr *const *>(param_type_end());
-    if (getExceptionSpecType() != EST_ComputedNoexcept)
-      eh_end += NumExceptions;
-    else
+    Expr *const *eh_end = reinterpret_cast<Expr *const *>(exception_end());
+    if (getExceptionSpecType() == EST_ComputedNoexcept)
       eh_end += 1; // NoexceptExpr
+    // The memory layout of these types isn't handled here, so
+    // hopefully this is never called for them?
+    assert(getExceptionSpecType() != EST_Uninstantiated &&
+           getExceptionSpecType() != EST_Unevaluated);
 
     return reinterpret_cast<const bool*>(eh_end);
   }
@@ -3295,7 +3297,6 @@
                       const ExtProtoInfo &EPI, const ASTContext &Context);
 };
 
-
 /// \brief Represents the dependent type named by a dependently-scoped
 /// typename using declaration, e.g.
 ///   using typename Base<T>::foo;
@@ -3936,8 +3937,9 @@
 /// TemplateArguments, followed by a QualType representing the
 /// non-canonical aliased type when the template is a type alias
 /// template.
-class TemplateSpecializationType
-  : public Type, public llvm::FoldingSetNode {
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) TemplateSpecializationType
+    : public Type,
+      public llvm::FoldingSetNode {
   /// The name of the template being specialized.  This is
   /// either a TemplateName::Template (in which case it is a
   /// ClassTemplateDecl*, a TemplateTemplateParmDecl*, or a
@@ -4328,8 +4330,9 @@
 /// Represents a template specialization type whose template cannot be
 /// resolved, e.g.
 ///   A<T>::template B<T>
-class DependentTemplateSpecializationType :
-  public TypeWithKeyword, public llvm::FoldingSetNode {
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) DependentTemplateSpecializationType
+    : public TypeWithKeyword,
+      public llvm::FoldingSetNode {
 
   /// The nested name specifier containing the qualifier.
   NestedNameSpecifier *NNS;
Index: cfe/trunk/include/clang/AST/TypeLoc.h
===================================================================
--- cfe/trunk/include/clang/AST/TypeLoc.h
+++ cfe/trunk/include/clang/AST/TypeLoc.h
@@ -206,6 +206,7 @@
 
 /// \brief Return the TypeLoc for a type source info.
 inline TypeLoc TypeSourceInfo::getTypeLoc() const {
+  // TODO: is this alignment already sufficient?
   return TypeLoc(Ty, const_cast<void*>(static_cast<const void*>(this + 1)));
 }
 
Index: cfe/trunk/include/clang/Sema/AttributeList.h
===================================================================
--- cfe/trunk/include/clang/Sema/AttributeList.h
+++ cfe/trunk/include/clang/Sema/AttributeList.h
@@ -137,11 +137,9 @@
   AttributeList *NextInPool;
 
   /// Arguments, if any, are stored immediately following the object.
-  ArgsUnion *getArgsBuffer() {
-    return reinterpret_cast<ArgsUnion*>(this+1);
-  }
+  ArgsUnion *getArgsBuffer() { return reinterpret_cast<ArgsUnion *>(this + 1); }
   ArgsUnion const *getArgsBuffer() const {
-    return reinterpret_cast<ArgsUnion const *>(this+1);
+    return reinterpret_cast<ArgsUnion const *>(this + 1);
   }
 
   enum AvailabilitySlot {
Index: cfe/trunk/lib/AST/Decl.cpp
===================================================================
--- cfe/trunk/lib/AST/Decl.cpp
+++ cfe/trunk/lib/AST/Decl.cpp
@@ -3116,8 +3116,8 @@
                              const TemplateArgumentListInfo &TemplateArgs) {
   assert(TemplateOrSpecialization.isNull());
   size_t Size = sizeof(DependentFunctionTemplateSpecializationInfo);
-  Size += Templates.size() * sizeof(FunctionTemplateDecl*);
   Size += TemplateArgs.size() * sizeof(TemplateArgumentLoc);
+  Size += Templates.size() * sizeof(FunctionTemplateDecl *);
   void *Buffer = Context.Allocate(Size);
   DependentFunctionTemplateSpecializationInfo *Info =
     new (Buffer) DependentFunctionTemplateSpecializationInfo(Templates,
@@ -3132,8 +3132,8 @@
   static_assert(sizeof(*this) % llvm::AlignOf<void *>::Alignment == 0,
                 "Trailing data is unaligned!");
 
-  d.NumTemplates = Ts.size();
-  d.NumArgs = TArgs.size();
+  NumTemplates = Ts.size();
+  NumArgs = TArgs.size();
 
   FunctionTemplateDecl **TsArray =
     const_cast<FunctionTemplateDecl**>(getTemplates());
Index: cfe/trunk/lib/AST/DeclBase.cpp
===================================================================
--- cfe/trunk/lib/AST/DeclBase.cpp
+++ cfe/trunk/lib/AST/DeclBase.cpp
@@ -45,10 +45,19 @@
   getASTContext().getExternalSource()->updateOutOfDateIdentifier(II);
 }
 
+#define DECL(DERIVED, BASE)                                                    \
+  static_assert(Decl::DeclObjAlignment >=                                      \
+                    llvm::AlignOf<DERIVED##Decl>::Alignment,                   \
+                "Alignment sufficient after objects prepended to " #DERIVED);
+#define ABSTRACT_DECL(DECL)
+#include "clang/AST/DeclNodes.inc"
+
 void *Decl::operator new(std::size_t Size, const ASTContext &Context,
                          unsigned ID, std::size_t Extra) {
   // Allocate an extra 8 bytes worth of storage, which ensures that the
-  // resulting pointer will still be 8-byte aligned. 
+  // resulting pointer will still be 8-byte aligned.
+  static_assert(sizeof(unsigned) * 2 >= DeclObjAlignment,
+                "Decl won't be misaligned");
   void *Start = Context.Allocate(Size + Extra + 8);
   void *Result = (char*)Start + 8;
 
@@ -69,7 +78,13 @@
   // With local visibility enabled, we track the owning module even for local
   // declarations.
   if (Ctx.getLangOpts().ModulesLocalVisibility) {
-    void *Buffer = ::operator new(sizeof(Module *) + Size + Extra, Ctx);
+    // Ensure required alignment of the resulting object by adding extra
+    // padding at the start if required.
+    size_t ExtraAlign =
+        llvm::OffsetToAlignment(sizeof(Module *), DeclObjAlignment);
+    char *Buffer = reinterpret_cast<char *>(
+        ::operator new(ExtraAlign + sizeof(Module *) + Size + Extra, Ctx));
+    Buffer += ExtraAlign;
     return new (Buffer) Module*(nullptr) + 1;
   }
   return ::operator new(Size + Extra, Ctx);
Index: cfe/trunk/lib/AST/Expr.cpp
===================================================================
--- cfe/trunk/lib/AST/Expr.cpp
+++ cfe/trunk/lib/AST/Expr.cpp
@@ -399,10 +399,15 @@
     Size += sizeof(NestedNameSpecifierLoc);
   if (FoundD)
     Size += sizeof(NamedDecl *);
-  if (TemplateArgs)
+  if (TemplateArgs) {
+    Size = llvm::RoundUpToAlignment(Size,
+                                    llvm::alignOf<ASTTemplateKWAndArgsInfo>());
     Size += ASTTemplateKWAndArgsInfo::sizeFor(TemplateArgs->size());
-  else if (TemplateKWLoc.isValid())
+  } else if (TemplateKWLoc.isValid()) {
+    Size = llvm::RoundUpToAlignment(Size,
+                                    llvm::alignOf<ASTTemplateKWAndArgsInfo>());
     Size += ASTTemplateKWAndArgsInfo::sizeFor(0);
+  }
 
   void *Mem = Context.Allocate(Size, llvm::alignOf<DeclRefExpr>());
   return new (Mem) DeclRefExpr(Context, QualifierLoc, TemplateKWLoc, D,
@@ -420,8 +425,11 @@
     Size += sizeof(NestedNameSpecifierLoc);
   if (HasFoundDecl)
     Size += sizeof(NamedDecl *);
-  if (HasTemplateKWAndArgsInfo)
+  if (HasTemplateKWAndArgsInfo) {
+    Size = llvm::RoundUpToAlignment(Size,
+                                    llvm::alignOf<ASTTemplateKWAndArgsInfo>());
     Size += ASTTemplateKWAndArgsInfo::sizeFor(NumTemplateArgs);
+  }
 
   void *Mem = Context.Allocate(Size, llvm::alignOf<DeclRefExpr>());
   return new (Mem) DeclRefExpr(EmptyShell());
@@ -3939,7 +3947,8 @@
                            SourceLocation ColonOrEqualLoc,
                            bool UsesColonSyntax, Expr *Init) {
   void *Mem = C.Allocate(sizeof(DesignatedInitExpr) +
-                         sizeof(Stmt *) * (IndexExprs.size() + 1), 8);
+                             sizeof(Stmt *) * (IndexExprs.size() + 1),
+                         llvm::alignOf<DesignatedInitExpr>());
   return new (Mem) DesignatedInitExpr(C, C.VoidTy, NumDesignators, Designators,
                                       ColonOrEqualLoc, UsesColonSyntax,
                                       IndexExprs, Init);
Index: cfe/trunk/lib/AST/ExprCXX.cpp
===================================================================
--- cfe/trunk/lib/AST/ExprCXX.cpp
+++ cfe/trunk/lib/AST/ExprCXX.cpp
@@ -1070,15 +1070,15 @@
   return capture_range(implicit_capture_begin(), implicit_capture_end());
 }
 
-ArrayRef<VarDecl *> 
-LambdaExpr::getCaptureInitIndexVars(capture_init_iterator Iter) const {
+ArrayRef<VarDecl *>
+LambdaExpr::getCaptureInitIndexVars(const_capture_init_iterator Iter) const {
   assert(HasArrayIndexVars && "No array index-var data?");
   
   unsigned Index = Iter - capture_init_begin();
   assert(Index < getLambdaClass()->getLambdaData().NumCaptures &&
          "Capture index out-of-range");
-  VarDecl **IndexVars = getArrayIndexVars();
-  unsigned *IndexStarts = getArrayIndexStarts();
+  VarDecl *const *IndexVars = getArrayIndexVars();
+  const unsigned *IndexStarts = getArrayIndexStarts();
   return llvm::makeArrayRef(IndexVars + IndexStarts[Index],
                             IndexVars + IndexStarts[Index + 1]);
 }
@@ -1099,9 +1099,13 @@
 }
 
 CompoundStmt *LambdaExpr::getBody() const {
+  // FIXME: this mutation in getBody is bogus. It should be
+  // initialized in ASTStmtReader::VisitLambdaExpr, but for reasons I
+  // don't understand, that doesn't work.
   if (!getStoredStmts()[NumCaptures])
-    getStoredStmts()[NumCaptures] = getCallOperator()->getBody();
-    
+    *const_cast<clang::Stmt **>(&getStoredStmts()[NumCaptures]) =
+        getCallOperator()->getBody();
+
   return reinterpret_cast<CompoundStmt *>(getStoredStmts()[NumCaptures]);
 }
 
Index: cfe/trunk/lib/AST/Stmt.cpp
===================================================================
--- cfe/trunk/lib/AST/Stmt.cpp
+++ cfe/trunk/lib/AST/Stmt.cpp
@@ -822,7 +822,7 @@
 CXXTryStmt *CXXTryStmt::Create(const ASTContext &C, SourceLocation tryLoc,
                                Stmt *tryBlock, ArrayRef<Stmt*> handlers) {
   std::size_t Size = sizeof(CXXTryStmt);
-  Size += ((handlers.size() + 1) * sizeof(Stmt));
+  Size += ((handlers.size() + 1) * sizeof(Stmt *));
 
   void *Mem = C.Allocate(Size, llvm::alignOf<CXXTryStmt>());
   return new (Mem) CXXTryStmt(tryLoc, tryBlock, handlers);
@@ -831,7 +831,7 @@
 CXXTryStmt *CXXTryStmt::Create(const ASTContext &C, EmptyShell Empty,
                                unsigned numHandlers) {
   std::size_t Size = sizeof(CXXTryStmt);
-  Size += ((numHandlers + 1) * sizeof(Stmt));
+  Size += ((numHandlers + 1) * sizeof(Stmt *));
 
   void *Mem = C.Allocate(Size, llvm::alignOf<CXXTryStmt>());
   return new (Mem) CXXTryStmt(Empty, numHandlers);
@@ -2250,4 +2250,3 @@
       C.Allocate(Size + sizeof(OMPClause *) * NumClauses + sizeof(Stmt *));
   return new (Mem) OMPTeamsDirective(NumClauses);
 }
-
Index: cfe/trunk/lib/CodeGen/CGCleanup.h
===================================================================
--- cfe/trunk/lib/CodeGen/CGCleanup.h
+++ cfe/trunk/lib/CodeGen/CGCleanup.h
@@ -216,7 +216,7 @@
 };
 
 /// A cleanup scope which generates the cleanup blocks lazily.
-class EHCleanupScope : public EHScope {
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) EHCleanupScope : public EHScope {
   /// The nearest normal cleanup scope enclosing this one.
   EHScopeStack::stable_iterator EnclosingNormal;
 
@@ -396,6 +396,15 @@
     return (Scope->getKind() == Cleanup);
   }
 };
+// NOTE: there's a bunch of different data classes tacked on after an
+// EHCleanupScope. It is asserted (in EHScopeStack::pushCleanup*) that
+// they don't require greater alignment than ScopeStackAlignment. So,
+// EHCleanupScope ought to have alignment equal to that -- not more
+// (would be misaligned by the stack allocator), and not less (would
+// break the appended classes).
+static_assert(llvm::AlignOf<EHCleanupScope>::Alignment ==
+                  EHScopeStack::ScopeStackAlignment,
+              "EHCleanupScope expected alignment");
 
 /// An exceptions scope which filters exceptions thrown through it.
 /// Only exceptions matching the filter types will be permitted to be
@@ -472,27 +481,27 @@
   EHScope &operator*() const { return *get(); }
 
   iterator &operator++() {
+    size_t Size;
     switch (get()->getKind()) {
     case EHScope::Catch:
-      Ptr += EHCatchScope::getSizeForNumHandlers(
-          static_cast<const EHCatchScope*>(get())->getNumHandlers());
+      Size = EHCatchScope::getSizeForNumHandlers(
+          static_cast<const EHCatchScope *>(get())->getNumHandlers());
       break;
 
     case EHScope::Filter:
-      Ptr += EHFilterScope::getSizeForNumFilters(
-          static_cast<const EHFilterScope*>(get())->getNumFilters());
+      Size = EHFilterScope::getSizeForNumFilters(
+          static_cast<const EHFilterScope *>(get())->getNumFilters());
       break;
 
     case EHScope::Cleanup:
-      Ptr += static_cast<const EHCleanupScope*>(get())
-        ->getAllocatedSize();
+      Size = static_cast<const EHCleanupScope *>(get())->getAllocatedSize();
       break;
 
     case EHScope::Terminate:
-      Ptr += EHTerminateScope::getSize();
+      Size = EHTerminateScope::getSize();
       break;
     }
-
+    Ptr += llvm::RoundUpToAlignment(Size, ScopeStackAlignment);
     return *this;
   }
 
@@ -528,7 +537,7 @@
 
   EHCatchScope &scope = cast<EHCatchScope>(*begin());
   InnermostEHScope = scope.getEnclosingEHScope();
-  StartOfData += EHCatchScope::getSizeForNumHandlers(scope.getNumHandlers());
+  deallocate(EHCatchScope::getSizeForNumHandlers(scope.getNumHandlers()));
 }
 
 inline void EHScopeStack::popTerminate() {
@@ -536,7 +545,7 @@
 
   EHTerminateScope &scope = cast<EHTerminateScope>(*begin());
   InnermostEHScope = scope.getEnclosingEHScope();
-  StartOfData += EHTerminateScope::getSize();
+  deallocate(EHTerminateScope::getSize());
 }
 
 inline EHScopeStack::iterator EHScopeStack::find(stable_iterator sp) const {
Index: cfe/trunk/lib/CodeGen/CGCleanup.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGCleanup.cpp
+++ cfe/trunk/lib/CodeGen/CGCleanup.cpp
@@ -96,6 +96,7 @@
 
 /// Push an entry of the given size onto this protected-scope stack.
 char *EHScopeStack::allocate(size_t Size) {
+  Size = llvm::RoundUpToAlignment(Size, ScopeStackAlignment);
   if (!StartOfBuffer) {
     unsigned Capacity = 1024;
     while (Capacity < Size) Capacity *= 2;
@@ -125,6 +126,10 @@
   return StartOfData;
 }
 
+void EHScopeStack::deallocate(size_t Size) {
+  StartOfData += llvm::RoundUpToAlignment(Size, ScopeStackAlignment);
+}
+
 bool EHScopeStack::containsOnlyLifetimeMarkers(
     EHScopeStack::stable_iterator Old) const {
   for (EHScopeStack::iterator it = begin(); stabilize(it) != Old; it++) {
@@ -166,7 +171,6 @@
 
 
 void *EHScopeStack::pushCleanup(CleanupKind Kind, size_t Size) {
-  assert(((Size % sizeof(void*)) == 0) && "cleanup type is misaligned");
   char *Buffer = allocate(EHCleanupScope::getSizeForCleanupSize(Size));
   bool IsNormalCleanup = Kind & NormalCleanup;
   bool IsEHCleanup = Kind & EHCleanup;
@@ -194,7 +198,7 @@
   EHCleanupScope &Cleanup = cast<EHCleanupScope>(*begin());
   InnermostNormalCleanup = Cleanup.getEnclosingNormalCleanup();
   InnermostEHScope = Cleanup.getEnclosingEHScope();
-  StartOfData += Cleanup.getAllocatedSize();
+  deallocate(Cleanup.getAllocatedSize());
 
   // Destroy the cleanup.
   Cleanup.Destroy();
@@ -224,7 +228,7 @@
   assert(!empty() && "popping exception stack when not empty");
 
   EHFilterScope &filter = cast<EHFilterScope>(*begin());
-  StartOfData += EHFilterScope::getSizeForNumFilters(filter.getNumFilters());
+  deallocate(EHFilterScope::getSizeForNumFilters(filter.getNumFilters()));
 
   InnermostEHScope = filter.getEnclosingEHScope();
 }
Index: cfe/trunk/lib/CodeGen/CGExprCXX.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGExprCXX.cpp
+++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp
@@ -1844,8 +1844,8 @@
       MakeAddrLValue(Slot.getAddr(), E->getType(), Slot.getAlignment());
 
   CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin();
-  for (LambdaExpr::capture_init_iterator i = E->capture_init_begin(),
-                                         e = E->capture_init_end();
+  for (LambdaExpr::const_capture_init_iterator i = E->capture_init_begin(),
+                                               e = E->capture_init_end();
        i != e; ++i, ++CurField) {
     // Emit initialization
     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
Index: cfe/trunk/lib/CodeGen/CGStmt.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGStmt.cpp
+++ cfe/trunk/lib/CodeGen/CGStmt.cpp
@@ -2156,8 +2156,8 @@
       CreateMemTemp(RecordTy, "agg.captured"), RecordTy);
 
   RecordDecl::field_iterator CurField = RD->field_begin();
-  for (CapturedStmt::capture_init_iterator I = S.capture_init_begin(),
-                                           E = S.capture_init_end();
+  for (CapturedStmt::const_capture_init_iterator I = S.capture_init_begin(),
+                                                 E = S.capture_init_end();
        I != E; ++I, ++CurField) {
     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
     if (CurField->hasCapturedVLAType()) {
Index: cfe/trunk/lib/CodeGen/EHScopeStack.h
===================================================================
--- cfe/trunk/lib/CodeGen/EHScopeStack.h
+++ cfe/trunk/lib/CodeGen/EHScopeStack.h
@@ -96,6 +96,8 @@
 /// and catch blocks.
 class EHScopeStack {
 public:
+  enum { ScopeStackAlignment = llvm::AlignOf<uint64_t>::Alignment };
+
   /// A saved depth on the scope stack.  This is necessary because
   /// pushing scopes onto the stack invalidates iterators.
   class stable_iterator {
@@ -248,6 +250,7 @@
   SmallVector<BranchFixup, 8> BranchFixups;
 
   char *allocate(size_t Size);
+  void deallocate(size_t Size);
 
   void *pushCleanup(CleanupKind K, size_t DataSize);
 
@@ -259,6 +262,8 @@
 
   /// Push a lazily-created cleanup on the stack.
   template <class T, class... As> void pushCleanup(CleanupKind Kind, As... A) {
+    static_assert(llvm::AlignOf<T>::Alignment <= ScopeStackAlignment,
+                  "Cleanup's alignment is too large.");
     void *Buffer = pushCleanup(Kind, sizeof(T));
     Cleanup *Obj = new (Buffer) T(A...);
     (void) Obj;
@@ -267,6 +272,8 @@
   /// Push a lazily-created cleanup on the stack. Tuple version.
   template <class T, class... As>
   void pushCleanupTuple(CleanupKind Kind, std::tuple<As...> A) {
+    static_assert(llvm::AlignOf<T>::Alignment <= ScopeStackAlignment,
+                  "Cleanup's alignment is too large.");
     void *Buffer = pushCleanup(Kind, sizeof(T));
     Cleanup *Obj = new (Buffer) T(std::move(A));
     (void) Obj;
@@ -287,6 +294,8 @@
   /// stack is modified.
   template <class T, class... As>
   T *pushCleanupWithExtra(CleanupKind Kind, size_t N, As... A) {
+    static_assert(llvm::AlignOf<T>::Alignment <= ScopeStackAlignment,
+                  "Cleanup's alignment is too large.");
     void *Buffer = pushCleanup(Kind, sizeof(T) + T::getExtraSize(N));
     return new (Buffer) T(N, A...);
   }
Index: cfe/trunk/lib/Sema/SemaExceptionSpec.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaExceptionSpec.cpp
+++ cfe/trunk/lib/Sema/SemaExceptionSpec.cpp
@@ -973,8 +973,9 @@
   case Expr::LambdaExprClass: {
     const LambdaExpr *Lambda = cast<LambdaExpr>(E);
     CanThrowResult CT = CT_Cannot;
-    for (LambdaExpr::capture_init_iterator Cap = Lambda->capture_init_begin(),
-                                        CapEnd = Lambda->capture_init_end();
+    for (LambdaExpr::const_capture_init_iterator
+             Cap = Lambda->capture_init_begin(),
+             CapEnd = Lambda->capture_init_end();
          Cap != CapEnd; ++Cap)
       CT = mergeCanThrow(CT, canThrow(*Cap));
     return CT;