Propagate the new exception information to FunctionProtoType.
Change the interface to expose the new information and deal with the enormous fallout.
Introduce the new ExceptionSpecificationType value EST_DynamicNone to more easily deal with empty throw specifications.
Update the tests for noexcept and fix the various bugs uncovered, such as lack of tentative parsing support.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@127537 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index fcfd230..c128ce5 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -1909,7 +1909,7 @@
   // Unique functions, to guarantee there is only one function of a particular
   // structure.
   llvm::FoldingSetNodeID ID;
-  FunctionProtoType::Profile(ID, ResultTy, ArgArray, NumArgs, EPI);
+  FunctionProtoType::Profile(ID, ResultTy, ArgArray, NumArgs, EPI, this);
 
   void *InsertPos = 0;
   if (FunctionProtoType *FTP =
@@ -1953,14 +1953,20 @@
 
   // FunctionProtoType objects are allocated with extra bytes after them
   // for two variable size arrays (for parameter and exception types) at the
-  // end of them.
+  // end of them. Instead of the exception types, there could be a noexcept
+  // expression and a context pointer.
   size_t Size = sizeof(FunctionProtoType) +
-                NumArgs * sizeof(QualType) +
-                EPI.NumExceptions * sizeof(QualType);
+                NumArgs * sizeof(QualType);
+  if (EPI.ExceptionSpecType == EST_Dynamic)
+    Size += EPI.NumExceptions * sizeof(QualType);
+  else if (EPI.ExceptionSpecType == EST_ComputedNoexcept) {
+    Size += sizeof(Expr*) + sizeof(ASTContext*);
+  }
   FunctionProtoType *FTP = (FunctionProtoType*) Allocate(Size, TypeAlignment);
   FunctionProtoType::ExtProtoInfo newEPI = EPI;
   newEPI.ExtInfo = EPI.ExtInfo.withCallingConv(CallConv);
-  new (FTP) FunctionProtoType(ResultTy, ArgArray, NumArgs, Canonical, newEPI);
+  new (FTP) FunctionProtoType(ResultTy, ArgArray, NumArgs, Canonical, newEPI,
+                              this);
   Types.push_back(FTP);
   FunctionProtoTypes.InsertNode(FTP, InsertPos);
   return QualType(FTP, 0);
diff --git a/lib/AST/ASTImporter.cpp b/lib/AST/ASTImporter.cpp
index b00c788..895f442 100644
--- a/lib/AST/ASTImporter.cpp
+++ b/lib/AST/ASTImporter.cpp
@@ -521,16 +521,21 @@
     }
     if (Proto1->isVariadic() != Proto2->isVariadic())
       return false;
-    if (Proto1->hasExceptionSpec() != Proto2->hasExceptionSpec())
+    if (Proto1->getExceptionSpecType() != Proto2->getExceptionSpecType())
       return false;
-    if (Proto1->hasAnyExceptionSpec() != Proto2->hasAnyExceptionSpec())
-      return false;
-    if (Proto1->getNumExceptions() != Proto2->getNumExceptions())
-      return false;
-    for (unsigned I = 0, N = Proto1->getNumExceptions(); I != N; ++I) {
+    if (Proto1->getExceptionSpecType() == EST_Dynamic) {
+      if (Proto1->getNumExceptions() != Proto2->getNumExceptions())
+        return false;
+      for (unsigned I = 0, N = Proto1->getNumExceptions(); I != N; ++I) {
+        if (!IsStructurallyEquivalent(Context,
+                                      Proto1->getExceptionType(I),
+                                      Proto2->getExceptionType(I)))
+          return false;
+      }
+    } else if (Proto1->getExceptionSpecType() == EST_ComputedNoexcept) {
       if (!IsStructurallyEquivalent(Context,
-                                    Proto1->getExceptionType(I),
-                                    Proto2->getExceptionType(I)))
+                                    Proto1->getNoexceptExpr(),
+                                    Proto2->getNoexceptExpr()))
         return false;
     }
     if (Proto1->getTypeQuals() != Proto2->getTypeQuals())
diff --git a/lib/AST/DeclPrinter.cpp b/lib/AST/DeclPrinter.cpp
index c6ae128..2781632 100644
--- a/lib/AST/DeclPrinter.cpp
+++ b/lib/AST/DeclPrinter.cpp
@@ -412,22 +412,32 @@
       if (TypeQuals & Qualifiers::Restrict)
         Proto += " restrict";
     }
-    
-    if (FT && FT->hasExceptionSpec()) {
+
+    if (FT && FT->hasDynamicExceptionSpec()) {
       Proto += " throw(";
-      if (FT->hasAnyExceptionSpec())
+      if (FT->getExceptionSpecType() == EST_MSAny)
         Proto += "...";
       else 
         for (unsigned I = 0, N = FT->getNumExceptions(); I != N; ++I) {
           if (I)
             Proto += ", ";
-          
-          
+
           std::string ExceptionType;
           FT->getExceptionType(I).getAsStringInternal(ExceptionType, SubPolicy);
           Proto += ExceptionType;
         }
       Proto += ")";
+    } else if (FT && isNoexceptExceptionSpec(FT->getExceptionSpecType())) {
+      Proto += " noexcept";
+      if (FT->getExceptionSpecType() == EST_ComputedNoexcept) {
+        Proto += "(";
+        llvm::raw_string_ostream EOut(Proto);
+        FT->getNoexceptExpr()->printPretty(EOut, Context, 0, SubPolicy,
+                                           Indentation);
+        EOut.flush();
+        Proto += EOut.str();
+        Proto += ")";
+      }
     }
 
     if (D->hasAttr<NoReturnAttr>())
diff --git a/lib/AST/DumpXML.cpp b/lib/AST/DumpXML.cpp
index 9d828fc..9a34722 100644
--- a/lib/AST/DumpXML.cpp
+++ b/lib/AST/DumpXML.cpp
@@ -975,15 +975,16 @@
       dispatch(*I);
     pop();
 
-    if (T->hasExceptionSpec()) {
+    if (T->hasDynamicExceptionSpec()) {
       push("exception_specifiers");
-      setFlag("any", T->hasAnyExceptionSpec());
+      setFlag("any", T->getExceptionSpecType() == EST_MSAny);
       completeAttrs();
       for (FunctionProtoType::exception_iterator
              I = T->exception_begin(), E = T->exception_end(); I != E; ++I)
         dispatch(*I);
       pop();
     }
+    // FIXME: noexcept specifier
   }
 
   void visitTemplateSpecializationTypeChildren(TemplateSpecializationType *T) {
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 4793b11..1c7807e 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -1659,7 +1659,7 @@
   if (!FT)
     return Expr::CT_Can;
 
-  return FT->hasEmptyExceptionSpec() ? Expr::CT_Cannot : Expr::CT_Can;
+  return FT->isNothrow() ? Expr::CT_Cannot : Expr::CT_Can;
 }
 
 static Expr::CanThrowResult CanDynamicCastThrow(const CXXDynamicCastExpr *DC) {
diff --git a/lib/AST/ExprCXX.cpp b/lib/AST/ExprCXX.cpp
index 966c1fe..fd94dd1 100644
--- a/lib/AST/ExprCXX.cpp
+++ b/lib/AST/ExprCXX.cpp
@@ -102,7 +102,7 @@
 
 bool CXXNewExpr::shouldNullCheckAllocation() const {
   return getOperatorNew()->getType()->
-    castAs<FunctionProtoType>()->hasNonThrowingExceptionSpec();
+    castAs<FunctionProtoType>()->isNothrow();
 }
 
 // CXXDeleteExpr
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index eea08f6..eb5254e 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -21,6 +21,7 @@
 #include "clang/AST/PrettyPrinter.h"
 #include "clang/AST/TypeVisitor.h"
 #include "clang/Basic/Specifiers.h"
+#include "llvm/ADT/APSInt.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
@@ -1165,7 +1166,8 @@
 
 FunctionProtoType::FunctionProtoType(QualType result, const QualType *args,
                                      unsigned numArgs, QualType canonical,
-                                     const ExtProtoInfo &epi)
+                                     const ExtProtoInfo &epi,
+                                     const ASTContext *context)
   : FunctionType(FunctionProto, result, epi.Variadic, epi.TypeQuals, 
                  epi.RefQualifier, canonical,
                  result->isDependentType(),
@@ -1173,8 +1175,7 @@
                  result->containsUnexpandedParameterPack(),
                  epi.ExtInfo),
     NumArgs(numArgs), NumExceptions(epi.NumExceptions),
-    HasExceptionSpec(isDynamicExceptionSpec(epi.ExceptionSpecType)),
-    HasAnyExceptionSpec(epi.ExceptionSpecType == EST_DynamicAny)
+    ExceptionSpecType(epi.ExceptionSpecType)
 {
   // Fill in the trailing argument array.
   QualType *argSlot = reinterpret_cast<QualType*>(this+1);
@@ -1187,20 +1188,54 @@
 
     argSlot[i] = args[i];
   }
-  
-  // Fill in the exception array.
-  QualType *exnSlot = argSlot + numArgs;
-  for (unsigned i = 0, e = epi.NumExceptions; i != e; ++i) {
-    if (epi.Exceptions[i]->isDependentType())
-      setDependent();
 
-    if (epi.Exceptions[i]->containsUnexpandedParameterPack())
-      setContainsUnexpandedParameterPack();
+  if (getExceptionSpecType() == EST_Dynamic) {
+    // Fill in the exception array.
+    QualType *exnSlot = argSlot + numArgs;
+    for (unsigned i = 0, e = epi.NumExceptions; i != e; ++i) {
+      if (epi.Exceptions[i]->isDependentType())
+        setDependent();
 
-    exnSlot[i] = epi.Exceptions[i];
+      if (epi.Exceptions[i]->containsUnexpandedParameterPack())
+        setContainsUnexpandedParameterPack();
+
+      exnSlot[i] = epi.Exceptions[i];
+    }
+  } else if (getExceptionSpecType() == EST_ComputedNoexcept) {
+    // Store the noexcept expression and context.
+    Expr **noexSlot = reinterpret_cast<Expr**>(argSlot + numArgs);
+    *noexSlot = epi.NoexceptExpr;
+    const ASTContext **contextSlot = const_cast<const ASTContext**>(
+        reinterpret_cast<ASTContext**>(noexSlot + 1));
+    *contextSlot = context;
   }
 }
 
+FunctionProtoType::NoexceptResult
+FunctionProtoType::getNoexceptSpec() const {
+  ExceptionSpecificationType est = getExceptionSpecType();
+  if (est == EST_BasicNoexcept)
+    return NR_Nothrow;
+
+  if (est != EST_ComputedNoexcept)
+    return NR_NoNoexcept;
+
+  Expr *noexceptExpr = getNoexceptExpr();
+  if (!noexceptExpr)
+    return NR_BadNoexcept;
+  if (noexceptExpr->isValueDependent())
+    return NR_Dependent;
+
+  llvm::APSInt value;
+  ASTContext& ctx = const_cast<ASTContext&>(*getContext());
+  bool isICE = noexceptExpr->isIntegerConstantExpr(value, ctx, 0,
+                                                   /*evaluated*/false);
+  (void)isICE;
+  assert(isICE && "AST should not contain bad noexcept expressions.");
+
+  return value.getBoolValue() ? NR_Nothrow : NR_Throw;
+}
+
 bool FunctionProtoType::isTemplateVariadic() const {
   for (unsigned ArgIdx = getNumArgs(); ArgIdx; --ArgIdx)
     if (isa<PackExpansionType>(getArgType(ArgIdx - 1)))
@@ -1211,23 +1246,27 @@
 
 void FunctionProtoType::Profile(llvm::FoldingSetNodeID &ID, QualType Result,
                                 const QualType *ArgTys, unsigned NumArgs,
-                                const ExtProtoInfo &epi) {
+                                const ExtProtoInfo &epi,
+                                const ASTContext *Context) {
   ID.AddPointer(Result.getAsOpaquePtr());
   for (unsigned i = 0; i != NumArgs; ++i)
     ID.AddPointer(ArgTys[i].getAsOpaquePtr());
   ID.AddBoolean(epi.Variadic);
   ID.AddInteger(epi.TypeQuals);
   ID.AddInteger(epi.RefQualifier);
-  if (isDynamicExceptionSpec(epi.ExceptionSpecType)) {
-    ID.AddBoolean(epi.ExceptionSpecType == EST_DynamicAny);
+  ID.AddInteger(epi.ExceptionSpecType);
+  if (epi.ExceptionSpecType == EST_Dynamic) {
     for (unsigned i = 0; i != epi.NumExceptions; ++i)
       ID.AddPointer(epi.Exceptions[i].getAsOpaquePtr());
+  } else if (epi.ExceptionSpecType == EST_ComputedNoexcept && epi.NoexceptExpr){
+    epi.NoexceptExpr->Profile(ID, *Context, true);
   }
   epi.ExtInfo.Profile(ID);
 }
 
 void FunctionProtoType::Profile(llvm::FoldingSetNodeID &ID) {
-  Profile(ID, getResultType(), arg_type_begin(), NumArgs, getExtProtoInfo());
+  Profile(ID, getResultType(), arg_type_begin(), NumArgs, getExtProtoInfo(),
+          getContext());
 }
 
 QualType TypedefType::desugar() const {
diff --git a/lib/AST/TypePrinter.cpp b/lib/AST/TypePrinter.cpp
index 254f463..d0267ca 100644
--- a/lib/AST/TypePrinter.cpp
+++ b/lib/AST/TypePrinter.cpp
@@ -421,12 +421,12 @@
     S += " &&";
     break;
   }
-  
-  if (T->hasExceptionSpec()) {
+
+  if (T->hasDynamicExceptionSpec()) {
     S += " throw(";
-    if (T->hasAnyExceptionSpec())
+    if (T->getExceptionSpecType() == EST_MSAny)
       S += "...";
-    else 
+    else
       for (unsigned I = 0, N = T->getNumExceptions(); I != N; ++I) {
         if (I)
           S += ", ";
@@ -436,6 +436,16 @@
         S += ExceptionType;
       }
     S += ")";
+  } else if (isNoexceptExceptionSpec(T->getExceptionSpecType())) {
+    S += " noexcept";
+    if (T->getExceptionSpecType() == EST_ComputedNoexcept) {
+      S += "(";
+      llvm::raw_string_ostream EOut(S);
+      T->getNoexceptExpr()->printPretty(EOut, 0, Policy);
+      EOut.flush();
+      S += EOut.str();
+      S += ")";
+    }
   }
 
   print(T->getResultType(), S);
diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index ca7469f..8d27c0c 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -1128,7 +1128,7 @@
   const FunctionType *FT = Ty->getAs<FunctionType>();
   if (FT) {
     if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
-      if (Proto->hasEmptyExceptionSpec())
+      if (Proto->isNothrow())
         return false;
   }
   return true;
diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 158e3a3..d72e6dc 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -709,7 +709,7 @@
       FuncAttrs |= llvm::Attribute::NoUnwind;
     else if (const FunctionDecl *Fn = dyn_cast<FunctionDecl>(TargetDecl)) {
       const FunctionProtoType *FPT = Fn->getType()->getAs<FunctionProtoType>();
-      if (FPT && FPT->hasEmptyExceptionSpec())
+      if (FPT && FPT->isNothrow())
         FuncAttrs |= llvm::Attribute::NoUnwind;
     }
 
diff --git a/lib/CodeGen/CGException.cpp b/lib/CodeGen/CGException.cpp
index 0b248bd..f05bc70 100644
--- a/lib/CodeGen/CGException.cpp
+++ b/lib/CodeGen/CGException.cpp
@@ -449,9 +449,8 @@
   if (Proto == 0)
     return;
 
-  assert(!Proto->hasAnyExceptionSpec() && "function with parameter pack");
-
-  if (!Proto->hasExceptionSpec())
+  // FIXME: What about noexcept?
+  if (!Proto->hasDynamicExceptionSpec())
     return;
 
   unsigned NumExceptions = Proto->getNumExceptions();
@@ -477,7 +476,7 @@
   if (Proto == 0)
     return;
 
-  if (!Proto->hasExceptionSpec())
+  if (!Proto->hasDynamicExceptionSpec())
     return;
 
   EHStack.popFilter();
diff --git a/lib/CodeGen/CGExprCXX.cpp b/lib/CodeGen/CGExprCXX.cpp
index 0ca0240..c9c8a6a 100644
--- a/lib/CodeGen/CGExprCXX.cpp
+++ b/lib/CodeGen/CGExprCXX.cpp
@@ -982,7 +982,7 @@
   // exception spec; for this part, we inline
   // CXXNewExpr::shouldNullCheckAllocation()) and we have an
   // interesting initializer.
-  bool nullCheck = allocatorType->hasNonThrowingExceptionSpec() &&
+  bool nullCheck = allocatorType->isNothrow() &&
     !(allocType->isPODType() && !E->hasInitializer());
 
   llvm::BasicBlock *nullCheckBB = 0;
diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index 7b11e92..2cd2398 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -2042,6 +2042,11 @@
     SourceLocation LParenLoc = ConsumeParen();
     NoexceptType = EST_ComputedNoexcept;
     NoexceptExpr = ParseConstantExpression();
+    // The argument must be contextually convertible to bool. We use
+    // ActOnBooleanCondition for this purpose.
+    if (!NoexceptExpr.isInvalid())
+      NoexceptExpr = Actions.ActOnBooleanCondition(getCurScope(), KeywordLoc,
+                                                   NoexceptExpr.get());
     SourceLocation RParenLoc = MatchRHSPunctuation(tok::r_paren, LParenLoc);
     NoexceptRange = SourceRange(KeywordLoc, RParenLoc);
   } else {
@@ -2090,7 +2095,7 @@
   if (!Tok.is(tok::l_paren)) {
     Diag(Tok, diag::err_expected_lparen_after) << "throw";
     SpecificationRange.setEnd(SpecificationRange.getBegin());
-    return EST_Dynamic;
+    return EST_DynamicNone;
   }
   SourceLocation LParenLoc = ConsumeParen();
 
@@ -2102,7 +2107,7 @@
       Diag(EllipsisLoc, diag::ext_ellipsis_exception_spec);
     SourceLocation RParenLoc = MatchRHSPunctuation(tok::r_paren, LParenLoc);
     SpecificationRange.setEnd(RParenLoc);
-    return EST_DynamicAny;
+    return EST_MSAny;
   }
 
   // Parse the sequence of type-ids.
@@ -2132,7 +2137,7 @@
   }
 
   SpecificationRange.setEnd(MatchRHSPunctuation(tok::r_paren, LParenLoc));
-  return EST_Dynamic;
+  return Exceptions.empty() ? EST_DynamicNone : EST_Dynamic;
 }
 
 /// ParseTrailingReturnType - Parse a trailing return type on a new-style
diff --git a/lib/Parse/ParseTentative.cpp b/lib/Parse/ParseTentative.cpp
index 1099327..68b599b 100644
--- a/lib/Parse/ParseTentative.cpp
+++ b/lib/Parse/ParseTentative.cpp
@@ -1238,6 +1238,16 @@
     if (!SkipUntil(tok::r_paren))
       return TPResult::Error();
   }
+  if (Tok.is(tok::kw_noexcept)) {
+    ConsumeToken();
+    // Possibly an expression as well.
+    if (Tok.is(tok::l_paren)) {
+      // Find the matching rparen.
+      ConsumeParen();
+      if (!SkipUntil(tok::r_paren))
+        return TPResult::Error();
+    }
+  }
 
   return TPResult::Ambiguous();
 }
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index c967864..3b2a062 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1552,8 +1552,8 @@
     mergeParamDeclAttributes(*ni, *oi, Context);    
 }
 
-/// MergeVarDecl - We parsed a variable 'New' which has the same name and scope
-/// as a previous declaration 'Old'.  Figure out how to merge their types,
+/// MergeVarDeclTypes - We parsed a variable 'New' which has the same name and
+/// scope as a previous declaration 'Old'.  Figure out how to merge their types,
 /// emitting diagnostics as appropriate.
 ///
 /// Declarations using the auto type specifier (C++ [decl.spec.auto]) call back
@@ -1570,8 +1570,10 @@
     if (AT && !AT->isDeduced()) {
       // We don't know what the new type is until the initializer is attached.
       return;
-    } else if (Context.hasSameType(New->getType(), Old->getType()))
-      return;
+    } else if (Context.hasSameType(New->getType(), Old->getType())) {
+      // These could still be something that needs exception specs checked.
+      return MergeVarDeclExceptionSpecs(New, Old);
+    }
     // C++ [basic.link]p10:
     //   [...] the types specified by all declarations referring to a given
     //   object or function shall be identical, except that declarations for an
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 2bce585..f655105 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -383,6 +383,48 @@
   return Invalid;
 }
 
+/// \brief Merge the exception specifications of two variable declarations.
+///
+/// This is called when there's a redeclaration of a VarDecl. The function
+/// checks if the redeclaration might have an exception specification and
+/// validates compatibility and merges the specs if necessary.
+void Sema::MergeVarDeclExceptionSpecs(VarDecl *New, VarDecl *Old) {
+  // Shortcut if exceptions are disabled.
+  if (!getLangOptions().CXXExceptions)
+    return;
+
+  assert(Context.hasSameType(New->getType(), Old->getType()) &&
+         "Should only be called if types are otherwise the same.");
+
+  QualType NewType = New->getType();
+  QualType OldType = Old->getType();
+
+  // We're only interested in pointers and references to functions, as well
+  // as pointers to member functions.
+  if (const ReferenceType *R = NewType->getAs<ReferenceType>()) {
+    NewType = R->getPointeeType();
+    OldType = OldType->getAs<ReferenceType>()->getPointeeType();
+  } else if (const PointerType *P = NewType->getAs<PointerType>()) {
+    NewType = P->getPointeeType();
+    OldType = OldType->getAs<PointerType>()->getPointeeType();
+  } else if (const MemberPointerType *M = NewType->getAs<MemberPointerType>()) {
+    NewType = M->getPointeeType();
+    OldType = OldType->getAs<MemberPointerType>()->getPointeeType();
+  }
+
+  if (!NewType->isFunctionProtoType())
+    return;
+
+  // There's lots of special cases for functions. For function pointers, system
+  // libraries are hopefully not as broken so that we don't need these
+  // workarounds.
+  if (CheckEquivalentExceptionSpec(
+        OldType->getAs<FunctionProtoType>(), Old->getLocation(),
+        NewType->getAs<FunctionProtoType>(), New->getLocation())) {
+    New->setInvalidDecl();
+  }
+}
+
 /// CheckCXXDefaultArguments - Verify that the default arguments for a
 /// function declaration are well-formed according to C++
 /// [dcl.fct.default].
@@ -2978,53 +3020,101 @@
   /// implicitly-declared special member functions.
   class ImplicitExceptionSpecification {
     ASTContext &Context;
-    bool AllowsAllExceptions;
+    // We order exception specifications thus:
+    // noexcept is the most restrictive, but is only used in C++0x.
+    // throw() comes next.
+    // Then a throw(collected exceptions)
+    // Finally no specification.
+    // throw(...) is used instead if any called function uses it.
+    ExceptionSpecificationType ComputedEST;
     llvm::SmallPtrSet<CanQualType, 4> ExceptionsSeen;
     llvm::SmallVector<QualType, 4> Exceptions;
-    
+
+    void ClearExceptions() {
+      ExceptionsSeen.clear();
+      Exceptions.clear();
+    }
+
   public:
     explicit ImplicitExceptionSpecification(ASTContext &Context) 
-      : Context(Context), AllowsAllExceptions(false) { }
-    
-    /// \brief Whether the special member function should have any
-    /// exception specification at all.
-    bool hasExceptionSpecification() const {
-      return !AllowsAllExceptions;
+      : Context(Context), ComputedEST(EST_BasicNoexcept) {
+      if (!Context.getLangOptions().CPlusPlus0x)
+        ComputedEST = EST_DynamicNone;
     }
-    
-    /// \brief Whether the special member function should have a
-    /// throw(...) exception specification (a Microsoft extension).
-    bool hasAnyExceptionSpecification() const {
-      return false;
+
+    /// \brief Get the computed exception specification type.
+    ExceptionSpecificationType getExceptionSpecType() const {
+      assert(ComputedEST != EST_ComputedNoexcept &&
+             "noexcept(expr) should not be a possible result");
+      return ComputedEST;
     }
-    
+
     /// \brief The number of exceptions in the exception specification.
     unsigned size() const { return Exceptions.size(); }
-    
+
     /// \brief The set of exceptions in the exception specification.
     const QualType *data() const { return Exceptions.data(); }
-    
-    /// \brief Note that 
+
+    /// \brief Integrate another called method into the collected data.
     void CalledDecl(CXXMethodDecl *Method) {
-      // If we already know that we allow all exceptions, do nothing.
-      if (AllowsAllExceptions || !Method)
+      // If we have an MSAny spec already, don't bother.
+      if (!Method || ComputedEST == EST_MSAny)
         return;
-      
+
       const FunctionProtoType *Proto
         = Method->getType()->getAs<FunctionProtoType>();
-      
+
+      ExceptionSpecificationType EST = Proto->getExceptionSpecType();
+
       // If this function can throw any exceptions, make a note of that.
-      if (!Proto->hasExceptionSpec() || Proto->hasAnyExceptionSpec()) {
-        AllowsAllExceptions = true;
-        ExceptionsSeen.clear();
-        Exceptions.clear();
+      if (EST == EST_MSAny || EST == EST_None) {
+        ClearExceptions();
+        ComputedEST = EST;
         return;
       }
-        
+
+      // If this function has a basic noexcept, it doesn't affect the outcome.
+      if (EST == EST_BasicNoexcept)
+        return;
+
+      // If we have a throw-all spec at this point, ignore the function.
+      if (ComputedEST == EST_None)
+        return;
+
+      // If we're still at noexcept(true) and there's a nothrow() callee,
+      // change to that specification.
+      if (EST == EST_DynamicNone) {
+        if (ComputedEST == EST_BasicNoexcept)
+          ComputedEST = EST_DynamicNone;
+        return;
+      }
+
+      // Check out noexcept specs.
+      if (EST == EST_ComputedNoexcept) {
+        FunctionProtoType::NoexceptResult NR = Proto->getNoexceptSpec();
+        assert(NR != FunctionProtoType::NR_NoNoexcept &&
+               "Must have noexcept result for EST_ComputedNoexcept.");
+        assert(NR != FunctionProtoType::NR_Dependent &&
+               "Should not generate implicit declarations for dependent cases, "
+               "and don't know how to handle them anyway.");
+
+        // noexcept(false) -> no spec on the new function
+        if (NR == FunctionProtoType::NR_Throw) {
+          ClearExceptions();
+          ComputedEST = EST_None;
+        }
+        // noexcept(true) won't change anything either.
+        return;
+      }
+
+      assert(EST == EST_Dynamic && "EST case not considered earlier.");
+      assert(ComputedEST != EST_None &&
+             "Shouldn't collect exceptions when throw-all is guaranteed.");
+      ComputedEST = EST_Dynamic;
       // Record the exceptions in this function's exception specification.
       for (FunctionProtoType::exception_iterator E = Proto->exception_begin(),
                                               EEnd = Proto->exception_end();
-           E != EEnd; ++E) 
+           E != EEnd; ++E)
         if (ExceptionsSeen.insert(Context.getCanonicalType(*E)))
           Exceptions.push_back(*E);
     }
@@ -4672,7 +4762,7 @@
   //   exception-specification. [...]
   ImplicitExceptionSpecification ExceptSpec(Context);
 
-  // Direct base-class destructors.
+  // Direct base-class constructors.
   for (CXXRecordDecl::base_class_iterator B = ClassDecl->bases_begin(),
                                        BEnd = ClassDecl->bases_end();
        B != BEnd; ++B) {
@@ -4688,8 +4778,8 @@
         ExceptSpec.CalledDecl(Constructor);
     }
   }
-  
-  // Virtual base-class destructors.
+
+  // Virtual base-class constructors.
   for (CXXRecordDecl::base_class_iterator B = ClassDecl->vbases_begin(),
                                        BEnd = ClassDecl->vbases_end();
        B != BEnd; ++B) {
@@ -4702,8 +4792,8 @@
         ExceptSpec.CalledDecl(Constructor);
     }
   }
-  
-  // Field destructors.
+
+  // Field constructors.
   for (RecordDecl::field_iterator F = ClassDecl->field_begin(),
                                FEnd = ClassDecl->field_end();
        F != FEnd; ++F) {
@@ -4720,9 +4810,7 @@
   }
 
   FunctionProtoType::ExtProtoInfo EPI;
-  EPI.ExceptionSpecType = ExceptSpec.hasExceptionSpecification() ?
-    (ExceptSpec.hasAnyExceptionSpecification() ? EST_DynamicAny : EST_Dynamic) :
-    EST_None;
+  EPI.ExceptionSpecType = ExceptSpec.getExceptionSpecType();
   EPI.NumExceptions = ExceptSpec.size();
   EPI.Exceptions = ExceptSpec.data();
 
@@ -4997,16 +5085,14 @@
       ExceptSpec.CalledDecl(
                     LookupDestructor(cast<CXXRecordDecl>(RecordTy->getDecl())));
   }
-  
+
   // Create the actual destructor declaration.
   FunctionProtoType::ExtProtoInfo EPI;
-  EPI.ExceptionSpecType = ExceptSpec.hasExceptionSpecification() ?
-    (ExceptSpec.hasAnyExceptionSpecification() ? EST_DynamicAny : EST_Dynamic) :
-    EST_None;
+  EPI.ExceptionSpecType = ExceptSpec.getExceptionSpecType();
   EPI.NumExceptions = ExceptSpec.size();
   EPI.Exceptions = ExceptSpec.data();
   QualType Ty = Context.getFunctionType(Context.VoidTy, 0, 0, EPI);
-  
+
   CanQualType ClassType
     = Context.getCanonicalType(Context.getTypeDeclType(ClassDecl));
   SourceLocation ClassLoc = ClassDecl->getLocation();
@@ -5014,9 +5100,9 @@
     = Context.DeclarationNames.getCXXDestructorName(ClassType);
   DeclarationNameInfo NameInfo(Name, ClassLoc);
   CXXDestructorDecl *Destructor
-    = CXXDestructorDecl::Create(Context, ClassDecl, ClassLoc, NameInfo, Ty, 0,
-                                /*isInline=*/true,
-                                /*isImplicitlyDeclared=*/true);
+      = CXXDestructorDecl::Create(Context, ClassDecl, ClassLoc, NameInfo, Ty, 0,
+                                  /*isInline=*/true,
+                                  /*isImplicitlyDeclared=*/true);
   Destructor->setAccess(AS_public);
   Destructor->setImplicit();
   Destructor->setTrivial(ClassDecl->hasTrivialDestructor());
@@ -5396,13 +5482,11 @@
         ExceptSpec.CalledDecl(CopyAssign);      
     }      
   }
-  
+
   //   An implicitly-declared copy assignment operator is an inline public
   //   member of its class.
   FunctionProtoType::ExtProtoInfo EPI;
-  EPI.ExceptionSpecType = ExceptSpec.hasExceptionSpecification() ?
-    (ExceptSpec.hasAnyExceptionSpecification() ? EST_DynamicAny : EST_Dynamic) :
-    EST_None;
+  EPI.ExceptionSpecType = ExceptSpec.getExceptionSpecType();
   EPI.NumExceptions = ExceptSpec.size();
   EPI.Exceptions = ExceptSpec.data();
   DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(OO_Equal);
@@ -5860,13 +5944,11 @@
         ExceptSpec.CalledDecl(CopyConstructor);
     }
   }
-  
+
   //   An implicitly-declared copy constructor is an inline public
   //   member of its class.
   FunctionProtoType::ExtProtoInfo EPI;
-  EPI.ExceptionSpecType = ExceptSpec.hasExceptionSpecification() ?
-    (ExceptSpec.hasAnyExceptionSpecification() ? EST_DynamicAny : EST_Dynamic) :
-    EST_None;
+  EPI.ExceptionSpecType = ExceptSpec.getExceptionSpecType();
   EPI.NumExceptions = ExceptSpec.size();
   EPI.Exceptions = ExceptSpec.data();
   DeclarationName Name
diff --git a/lib/Sema/SemaExceptionSpec.cpp b/lib/Sema/SemaExceptionSpec.cpp
index dce4c6e..01ee712 100644
--- a/lib/Sema/SemaExceptionSpec.cpp
+++ b/lib/Sema/SemaExceptionSpec.cpp
@@ -105,7 +105,8 @@
                                     New->getType()->getAs<FunctionProtoType>(),
                                     New->getLocation(),
                                     &MissingExceptionSpecification,
-                                    &MissingEmptyExceptionSpecification))
+                                    &MissingEmptyExceptionSpecification,
+                                    /*AllowNoexceptAllMatchWithNoSpec=*/true))
     return false;
 
   // The failure was something other than an empty exception
@@ -129,8 +130,7 @@
        Context.getSourceManager().isInSystemHeader(Old->getLocation())) &&
       Old->isExternC()) {
     FunctionProtoType::ExtProtoInfo EPI = NewProto->getExtProtoInfo();
-    EPI.ExceptionSpecType = EST_Dynamic;
-    EPI.NumExceptions = 0;
+    EPI.ExceptionSpecType = EST_DynamicNone;
     QualType NewType = Context.getFunctionType(NewProto->getResultType(),
                                                NewProto->arg_type_begin(),
                                                NewProto->getNumArgs(),
@@ -144,11 +144,14 @@
       = Old->getType()->getAs<FunctionProtoType>();
 
     FunctionProtoType::ExtProtoInfo EPI = NewProto->getExtProtoInfo();
-    EPI.ExceptionSpecType = OldProto->hasExceptionSpec() ?
-      (OldProto->hasAnyExceptionSpec() ? EST_DynamicAny : EST_Dynamic) :
-      EST_None;
-    EPI.NumExceptions = OldProto->getNumExceptions();
-    EPI.Exceptions = OldProto->exception_begin();
+    EPI.ExceptionSpecType = OldProto->getExceptionSpecType();
+    if (EPI.ExceptionSpecType == EST_Dynamic) {
+      EPI.NumExceptions = OldProto->getNumExceptions();
+      EPI.Exceptions = OldProto->exception_begin();
+    } else if (EPI.ExceptionSpecType == EST_ComputedNoexcept) {
+      // FIXME: We can't just take the expression from the old prototype. It
+      // likely contains references to the old prototype's parameters.
+    }
 
     // Update the type of the function with the appropriate exception
     // specification.
@@ -178,20 +181,43 @@
     // Warn about the lack of exception specification.
     llvm::SmallString<128> ExceptionSpecString;
     llvm::raw_svector_ostream OS(ExceptionSpecString);
-    OS << "throw(";
-    bool OnFirstException = true;
-    for (FunctionProtoType::exception_iterator E = OldProto->exception_begin(),
-                                            EEnd = OldProto->exception_end();
-         E != EEnd;
-         ++E) {
-      if (OnFirstException)
-        OnFirstException = false;
-      else
-        OS << ", ";
-      
-      OS << E->getAsString(Context.PrintingPolicy);
+    switch (OldProto->getExceptionSpecType()) {
+    case EST_DynamicNone:
+      OS << "throw()";
+      break;
+
+    case EST_Dynamic: {
+      OS << "throw(";
+      bool OnFirstException = true;
+      for (FunctionProtoType::exception_iterator E = OldProto->exception_begin(),
+                                              EEnd = OldProto->exception_end();
+           E != EEnd;
+           ++E) {
+        if (OnFirstException)
+          OnFirstException = false;
+        else
+          OS << ", ";
+        
+        OS << E->getAsString(Context.PrintingPolicy);
+      }
+      OS << ")";
+      break;
     }
-    OS << ")";
+
+    case EST_BasicNoexcept:
+      OS << "noexcept";
+      break;
+
+    case EST_ComputedNoexcept:
+      OS << "noexcept(";
+      OldProto->getNoexceptExpr()->printPretty(OS, Context, 0,
+                                               Context.PrintingPolicy);
+      OS << ")";
+      break;
+
+    default:
+      assert(false && "This spec type is compatible with none.");
+    }
     OS.flush();
 
     SourceLocation FixItLoc;
@@ -236,18 +262,17 @@
                                       Old, OldLoc, New, NewLoc);
 }
 
-/// CheckEquivalentExceptionSpec - Check if the two types have equivalent
-/// exception specifications. Exception specifications are equivalent if
-/// they allow exactly the same set of exception types. It does not matter how
-/// that is achieved. See C++ [except.spec]p2.
-bool Sema::CheckEquivalentExceptionSpec(const PartialDiagnostic &DiagID, 
+/// CheckEquivalentExceptionSpec - Check if the two types have compatible
+/// exception specifications. See C++ [except.spec]p3.
+bool Sema::CheckEquivalentExceptionSpec(const PartialDiagnostic &DiagID,
                                         const PartialDiagnostic & NoteID,
-                                        const FunctionProtoType *Old, 
+                                        const FunctionProtoType *Old,
                                         SourceLocation OldLoc,
-                                        const FunctionProtoType *New, 
+                                        const FunctionProtoType *New,
                                         SourceLocation NewLoc,
                                         bool *MissingExceptionSpecification,
-                                     bool *MissingEmptyExceptionSpecification)  {
+                                        bool*MissingEmptyExceptionSpecification,
+                                        bool AllowNoexceptAllMatchWithNoSpec) {
   // Just completely ignore this under -fno-exceptions.
   if (!getLangOptions().CXXExceptions)
     return false;
@@ -258,29 +283,109 @@
   if (MissingEmptyExceptionSpecification)
     *MissingEmptyExceptionSpecification = false;
 
-  bool OldAny = !Old->hasExceptionSpec() || Old->hasAnyExceptionSpec();
-  bool NewAny = !New->hasExceptionSpec() || New->hasAnyExceptionSpec();
-  if (getLangOptions().Microsoft) {
-    // Treat throw(whatever) as throw(...) to be compatible with MS headers.
-    if (New->hasExceptionSpec() && New->getNumExceptions() > 0)
-      NewAny = true;
-    if (Old->hasExceptionSpec() && Old->getNumExceptions() > 0)
-      OldAny = true;
+  // C++0x [except.spec]p3: Two exception-specifications are compatible if:
+  //   - both are non-throwing, regardless of their form,
+  //   - both have the form noexcept(constant-expression) and the constant-
+  //     expressions are equivalent,
+  //   - one exception-specification is a noexcept-specification allowing all
+  //     exceptions and the other is of the form throw(type-id-list), or
+  //   - both are dynamic-exception-specifications that have the same set of
+  //     adjusted types.
+  //
+  // C++0x [except.spec]p12: An exception-specifcation is non-throwing if it is
+  //   of the form throw(), noexcept, or noexcept(constant-expression) where the
+  //   constant-expression yields true.
+  //
+  // CWG 1073 Proposed resolution: Strike the third bullet above.
+  //
+  // C++0x [except.spec]p4: If any declaration of a function has an exception-
+  //   specifier that is not a noexcept-specification allowing all exceptions,
+  //   all declarations [...] of that function shall have a compatible
+  //   exception-specification.
+  //
+  // That last point basically means that noexcept(false) matches no spec.
+  // It's considered when AllowNoexceptAllMatchWithNoSpec is true.
+
+  ExceptionSpecificationType OldEST = Old->getExceptionSpecType();
+  ExceptionSpecificationType NewEST = New->getExceptionSpecType();
+
+  // Shortcut the case where both have no spec.
+  if (OldEST == EST_None && NewEST == EST_None)
+    return false;
+
+  FunctionProtoType::NoexceptResult OldNR = Old->getNoexceptSpec();
+  FunctionProtoType::NoexceptResult NewNR = New->getNoexceptSpec();
+  if (OldNR == FunctionProtoType::NR_BadNoexcept ||
+      NewNR == FunctionProtoType::NR_BadNoexcept)
+    return false;
+
+  // Dependent noexcept specifiers are compatible with each other, but nothing
+  // else.
+  // One noexcept is compatible with another if the argument is the same
+  if (OldNR == NewNR &&
+      OldNR != FunctionProtoType::NR_NoNoexcept &&
+      NewNR != FunctionProtoType::NR_NoNoexcept)
+    return false;
+  if (OldNR != NewNR &&
+      OldNR != FunctionProtoType::NR_NoNoexcept &&
+      NewNR != FunctionProtoType::NR_NoNoexcept) {
+    Diag(NewLoc, DiagID);
+    if (NoteID.getDiagID() != 0)
+      Diag(OldLoc, NoteID);
+    return true;
   }
 
-  if (OldAny && NewAny)
+  if (getLangOptions().Microsoft) {
+    // Treat throw(whatever) as throw(...) to be compatible with MS headers.
+    if (OldEST == EST_Dynamic)
+      OldEST = EST_MSAny;
+    if (NewEST == EST_Dynamic)
+      NewEST = EST_MSAny;
+  }
+
+  // The MS extension throw(...) is compatible with itself.
+  if (OldEST == EST_MSAny && NewEST == EST_MSAny)
     return false;
-  if (OldAny || NewAny) {
+
+  // It's also compatible with no spec.
+  if ((OldEST == EST_None && NewEST == EST_MSAny) ||
+      (OldEST == EST_MSAny && NewEST == EST_None))
+    return false;
+
+  // It's also compatible with noexcept(false).
+  if (OldEST == EST_MSAny && NewNR == FunctionProtoType::NR_Throw)
+    return false;
+  if (NewEST == EST_MSAny && OldNR == FunctionProtoType::NR_Throw)
+    return false;
+
+  // As described above, noexcept(false) matches no spec only for functions.
+  if (AllowNoexceptAllMatchWithNoSpec) {
+    if (OldEST == EST_None && NewNR == FunctionProtoType::NR_Throw)
+      return false;
+    if (NewEST == EST_None && OldNR == FunctionProtoType::NR_Throw)
+      return false;
+  }
+
+  // Any non-throwing specifications are compatible.
+  bool OldNonThrowing = OldNR == FunctionProtoType::NR_Nothrow ||
+                        OldEST == EST_DynamicNone;
+  bool NewNonThrowing = NewNR == FunctionProtoType::NR_Nothrow ||
+                        NewEST == EST_DynamicNone;
+  if (OldNonThrowing && NewNonThrowing)
+    return false;
+
+  // At this point, the only remaining valid case is two matching dynamic
+  // specifications. We return here unless both specifications are dynamic.
+  if (OldEST != EST_Dynamic || NewEST != EST_Dynamic) {
     if (MissingExceptionSpecification && Old->hasExceptionSpec() &&
         !New->hasExceptionSpec()) {
       // The old type has an exception specification of some sort, but
       // the new type does not.
       *MissingExceptionSpecification = true;
 
-      if (MissingEmptyExceptionSpecification && 
-          !Old->hasAnyExceptionSpec() && Old->getNumExceptions() == 0) {
-        // The old type has a throw() exception specification and the
-        // new type has no exception specification, and the caller asked
+      if (MissingEmptyExceptionSpecification && OldNonThrowing) {
+        // The old type has a throw() or noexcept(true) exception specification
+        // and the new type has no exception specification, and the caller asked
         // to handle this itself.
         *MissingEmptyExceptionSpecification = true;
       }
@@ -294,8 +399,11 @@
     return true;
   }
 
+  assert(OldEST == EST_Dynamic && NewEST == EST_Dynamic &&
+      "Exception compatibility logic error: non-dynamic spec slipped through.");
+
   bool Success = true;
-  // Both have a definite exception spec. Collect the first set, then compare
+  // Both have a dynamic exception spec. Collect the first set, then compare
   // to the second.
   llvm::SmallPtrSet<CanQualType, 8> OldTypes, NewTypes;
   for (FunctionProtoType::exception_iterator I = Old->exception_begin(),
@@ -340,19 +448,66 @@
   if (!SubLoc.isValid())
     SubLoc = SuperLoc;
 
+  ExceptionSpecificationType SuperEST = Superset->getExceptionSpecType();
+
   // If superset contains everything, we're done.
-  if (!Superset->hasExceptionSpec() || Superset->hasAnyExceptionSpec())
+  if (SuperEST == EST_None || SuperEST == EST_MSAny)
     return CheckParamExceptionSpec(NoteID, Superset, SuperLoc, Subset, SubLoc);
 
+  // If there are dependent noexcept specs, assume everything is fine. Unlike
+  // with the equivalency check, this is safe in this case, because we don't
+  // want to merge declarations. Checks after instantiation will catch any
+  // omissions we make here.
+  // We also shortcut checking if a noexcept expression was bad.
+
+  FunctionProtoType::NoexceptResult SuperNR =Superset->getNoexceptSpec();
+  if (SuperNR == FunctionProtoType::NR_BadNoexcept ||
+      SuperNR == FunctionProtoType::NR_Dependent)
+    return false;
+
+  // Another case of the superset containing everything.
+  if (SuperNR == FunctionProtoType::NR_Throw)
+    return CheckParamExceptionSpec(NoteID, Superset, SuperLoc, Subset, SubLoc);
+
+  ExceptionSpecificationType SubEST = Subset->getExceptionSpecType();
+
   // It does not. If the subset contains everything, we've failed.
-  if (!Subset->hasExceptionSpec() || Subset->hasAnyExceptionSpec()) {
+  if (SubEST == EST_None || SubEST == EST_MSAny) {
     Diag(SubLoc, DiagID);
     if (NoteID.getDiagID() != 0)
       Diag(SuperLoc, NoteID);
     return true;
   }
 
-  // Neither contains everything. Do a proper comparison.
+  FunctionProtoType::NoexceptResult SubNR = Subset->getNoexceptSpec();
+  if (SubNR == FunctionProtoType::NR_BadNoexcept ||
+      SubNR == FunctionProtoType::NR_Dependent)
+    return false;
+
+  // Another case of the subset containing everything.
+  if (SubNR == FunctionProtoType::NR_Throw) {
+    Diag(SubLoc, DiagID);
+    if (NoteID.getDiagID() != 0)
+      Diag(SuperLoc, NoteID);
+    return true;
+  }
+
+  // If the subset contains nothing, we're done.
+  if (SubEST == EST_DynamicNone || SubNR == FunctionProtoType::NR_Nothrow)
+    return CheckParamExceptionSpec(NoteID, Superset, SuperLoc, Subset, SubLoc);
+
+  // Otherwise, if the superset contains nothing, we've failed.
+  if (SuperEST == EST_DynamicNone || SuperNR == FunctionProtoType::NR_Nothrow) {
+    Diag(SubLoc, DiagID);
+    if (NoteID.getDiagID() != 0)
+      Diag(SuperLoc, NoteID);
+    return true;
+  }
+
+  assert(SuperEST == EST_Dynamic && SubEST == EST_Dynamic &&
+         "Exception spec subset: non-dynamic case slipped through.");
+
+  // Neither contains everything or nothing. Do a proper comparison.
   for (FunctionProtoType::exception_iterator SubI = Subset->exception_begin(),
        SubE = Subset->exception_end(); SubI != SubE; ++SubI) {
     // Take one type from the subset.
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 25f042c..a1cd43a 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -1501,10 +1501,12 @@
   }
 
   FunctionProtoType::ExtProtoInfo EPI;
-  EPI.ExceptionSpecType = EST_Dynamic;
   if (HasBadAllocExceptionSpec) {
+    EPI.ExceptionSpecType = EST_Dynamic;
     EPI.NumExceptions = 1;
     EPI.Exceptions = &BadAllocType;
+  } else {
+    EPI.ExceptionSpecType = EST_DynamicNone;
   }
 
   QualType FnType = Context.getFunctionType(Return, &Argument, 1, EPI);
@@ -2421,7 +2423,7 @@
             FoundAssign = true;
             const FunctionProtoType *CPT
                 = Operator->getType()->getAs<FunctionProtoType>();
-            if (!CPT->hasEmptyExceptionSpec()) {
+            if (!CPT->isNothrow()) {
               AllNoThrow = false;
               break;
             }
@@ -2461,9 +2463,9 @@
           FoundConstructor = true;
           const FunctionProtoType *CPT
               = Constructor->getType()->getAs<FunctionProtoType>();
-          // TODO: check whether evaluating default arguments can throw.
+          // FIXME: check whether evaluating default arguments can throw.
           // For now, we'll be conservative and assume that they can throw.
-          if (!CPT->hasEmptyExceptionSpec() || CPT->getNumArgs() > 1) {
+          if (!CPT->isNothrow() || CPT->getNumArgs() > 1) {
             AllNoThrow = false;
             break;
           }
@@ -2498,7 +2500,7 @@
               = Constructor->getType()->getAs<FunctionProtoType>();
           // TODO: check whether evaluating default arguments can throw.
           // For now, we'll be conservative and assume that they can throw.
-          return CPT->hasEmptyExceptionSpec() && CPT->getNumArgs() == 0;
+          return CPT->isNothrow() && CPT->getNumArgs() == 0;
         }
       }
     }
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index e60882d..441149f 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2085,8 +2085,7 @@
   const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();
   assert(Proto && "Function template without prototype?");
 
-  if (Proto->hasExceptionSpec() || Proto->hasAnyExceptionSpec() ||
-      Proto->getNoReturnAttr()) {
+  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {
     // The function has an exception specification or a "noreturn"
     // attribute. Substitute into each of the exception types.
     llvm::SmallVector<QualType, 4> Exceptions;
@@ -2100,7 +2099,7 @@
                                                 Unexpanded);
         assert(!Unexpanded.empty() && 
                "Pack expansion without parameter packs?");
-        
+
         bool Expand = false;
         bool RetainExpansion = false;
         llvm::Optional<unsigned> NumExpansions
@@ -2114,7 +2113,7 @@
                                                     RetainExpansion,
                                                     NumExpansions))
           break;
-                      
+
         if (!Expand) {
           // We can't expand this pack expansion into separate arguments yet;
           // just substitute into the pattern and create a new pack expansion 
@@ -2130,7 +2129,7 @@
           Exceptions.push_back(T);
           continue;
         }
-        
+
         // Substitute into the pack expansion pattern for each template
         bool Invalid = false;
         for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
@@ -2143,13 +2142,13 @@
             Invalid = true;
             break;
           }
-          
+
           Exceptions.push_back(T);
         }
-        
+
         if (Invalid)
           break;
-        
+
         continue;
       }
       
@@ -2166,9 +2165,8 @@
     // Rebuild the function type 
 
     FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
-    EPI.ExceptionSpecType = Proto->hasExceptionSpec() ?
-      (Proto->hasAnyExceptionSpec() ? EST_DynamicAny : EST_Dynamic) :
-      EST_None;
+    // FIXME: Handle noexcept
+    EPI.ExceptionSpecType = Proto->getExceptionSpecType();
     EPI.NumExceptions = Exceptions.size();
     EPI.Exceptions = Exceptions.data();
     EPI.ExtInfo = Proto->getExtInfo();
diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index 62bf8e6..f49a49c 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -1901,7 +1901,22 @@
           EPI.NumExceptions = Exceptions.size();
           EPI.Exceptions = Exceptions.data();
         } else if (FTI.getExceptionSpecType() == EST_ComputedNoexcept) {
-          EPI.NoexceptExpr = FTI.NoexceptExpr;
+          // If an error occurred, there's no expression here.
+          if (Expr *NoexceptExpr = FTI.NoexceptExpr) {
+            assert((NoexceptExpr->isTypeDependent() ||
+                    NoexceptExpr->getType()->getCanonicalTypeUnqualified() ==
+                        Context.BoolTy) &&
+                 "Parser should have made sure that the expression is boolean");
+            SourceLocation ErrLoc;
+            llvm::APSInt Dummy;
+            if (!NoexceptExpr->isValueDependent() &&
+                !NoexceptExpr->isIntegerConstantExpr(Dummy, Context, &ErrLoc,
+                                                     /*evaluated*/false))
+              Diag(ErrLoc, diag::err_noexcept_needs_constant_expression)
+                  << NoexceptExpr->getSourceRange();
+            else
+              EPI.NoexceptExpr = NoexceptExpr;
+          }
         }
 
         T = Context.getFunctionType(T, ArgTys.data(), ArgTys.size(), EPI);
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 1283525..b34b62a 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -3117,15 +3117,18 @@
     EPI.Variadic = Record[Idx++];
     EPI.TypeQuals = Record[Idx++];
     EPI.RefQualifier = static_cast<RefQualifierKind>(Record[Idx++]);
-    bool HasExceptionSpec = Record[Idx++];
-    bool HasAnyExceptionSpec = Record[Idx++];
-    EPI.ExceptionSpecType = HasExceptionSpec ?
-        (HasAnyExceptionSpec ? EST_DynamicAny : EST_Dynamic) : EST_None;
-    EPI.NumExceptions = Record[Idx++];
-    llvm::SmallVector<QualType, 2> Exceptions;
-    for (unsigned I = 0; I != EPI.NumExceptions; ++I)
-      Exceptions.push_back(GetType(Record[Idx++]));
-    EPI.Exceptions = Exceptions.data();
+    ExceptionSpecificationType EST =
+        static_cast<ExceptionSpecificationType>(Record[Idx++]);
+    EPI.ExceptionSpecType = EST;
+    if (EST == EST_Dynamic) {
+      EPI.NumExceptions = Record[Idx++];
+      llvm::SmallVector<QualType, 2> Exceptions;
+      for (unsigned I = 0; I != EPI.NumExceptions; ++I)
+        Exceptions.push_back(GetType(Record[Idx++]));
+      EPI.Exceptions = Exceptions.data();
+    } else if (EST == EST_ComputedNoexcept) {
+      EPI.NoexceptExpr = ReadExpr(*Loc.F);
+    }
     return Context->getFunctionType(ResultType, ParamTypes.data(), NumParams,
                                     EPI);
   }
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index 5f83097..877650f 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -178,11 +178,14 @@
   Record.push_back(T->isVariadic());
   Record.push_back(T->getTypeQuals());
   Record.push_back(static_cast<unsigned>(T->getRefQualifier()));
-  Record.push_back(T->hasExceptionSpec());
-  Record.push_back(T->hasAnyExceptionSpec());
-  Record.push_back(T->getNumExceptions());
-  for (unsigned I = 0, N = T->getNumExceptions(); I != N; ++I)
-    Writer.AddTypeRef(T->getExceptionType(I), Record);
+  Record.push_back(T->getExceptionSpecType());
+  if (T->getExceptionSpecType() == EST_Dynamic) {
+    Record.push_back(T->getNumExceptions());
+    for (unsigned I = 0, N = T->getNumExceptions(); I != N; ++I)
+      Writer.AddTypeRef(T->getExceptionType(I), Record);
+  } else if (T->getExceptionSpecType() == EST_ComputedNoexcept) {
+    Writer.AddStmt(T->getNoexceptExpr());
+  }
   Code = TYPE_FUNCTION_PROTO;
 }