Revert r217995 and follow-ups:

r218053: Use exceptions() instead of getNumExceptions()/getExceptionType() to avoid
r218011: Work around MSVC parser bug by putting redundant braces around the body of
r217997: Skip parens when detecting whether we're instantiating a function declaration.
r217995: Instantiate exception specifications when instantiating function types (other

The Windows build was broken for 16 hours and no one had any good ideas of how to
fix it. Reverting for now to make the builders green. See the cfe-commits thread [1] for
more info.

This was the build error (from [2]):

C:\bb-win7\ninja-clang-i686-msc17-R\llvm-project\clang\lib\Sema\SemaTemplateInstantiate.cpp(1590) : error C2668: '`anonymous-namespace'::TemplateInstantiator::TransformFunctionProtoType' : ambiguous call to overloaded function
        C:\bb-win7\ninja-clang-i686-msc17-R\llvm-project\clang\lib\Sema\SemaTemplateInstantiate.cpp(1313): could be 'clang::QualType `anonymous-namespace'::TemplateInstantiator::TransformFunctionProtoType<clang::Sema::SubstFunctionDeclType::<lambda_756edcbe7bd5c7584849a6e3a1491735>>(clang::TypeLocBuilder &,clang::FunctionProtoTypeLoc,clang::CXXRecordDecl *,unsigned int,Fn)'
        with
        [
            Fn=clang::Sema::SubstFunctionDeclType::<lambda_756edcbe7bd5c7584849a6e3a1491735>
        ]
        c:\bb-win7\ninja-clang-i686-msc17-r\llvm-project\clang\lib\sema\TreeTransform.h(4532): or       'clang::QualType clang::TreeTransform<Derived>::TransformFunctionProtoType<clang::Sema::SubstFunctionDeclType::<lambda_756edcbe7bd5c7584849a6e3a1491735>>(clang::TypeLocBuilder &,clang::FunctionProtoTypeLoc,clang::CXXRecordDecl *,unsigned int,Fn)'
        with
        [
            Derived=`anonymous-namespace'::TemplateInstantiator,
            Fn=clang::Sema::SubstFunctionDeclType::<lambda_756edcbe7bd5c7584849a6e3a1491735>
        ]
        while trying to match the argument list '(clang::TypeLocBuilder, clang::FunctionProtoTypeLoc, clang::CXXRecordDecl *, unsigned int, clang::Sema::SubstFunctionDeclType::<lambda_756edcbe7bd5c7584849a6e3a1491735>)'

 1. http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20140915/115011.html
 2. http://bb.pgr.jp/builders/ninja-clang-i686-msc17-R/builds/10515/steps/build_clang_tools_1/logs/stdio

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@218058 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 133 insertions, 35 deletions

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index ddd47ee1e3..62a3e11ac9 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2988,7 +2988,7 @@ TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,
 /// Introduce the instantiated function parameters into the local
 /// instantiation scope, and set the parameter names to those used
 /// in the template.
-static bool addInstantiatedParametersToScope(Sema &S, FunctionDecl *Function,
+static void addInstantiatedParametersToScope(Sema &S, FunctionDecl *Function,
                                              const FunctionDecl *PatternDecl,
                                              LocalInstantiationScope &Scope,
                            const MultiLevelTemplateArgumentList &TemplateArgs) {
@@ -2999,22 +2999,15 @@ static bool addInstantiatedParametersToScope(Sema &S, FunctionDecl *Function,
       // Simple case: not a parameter pack.
       assert(FParamIdx < Function->getNumParams());
       ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
-      FunctionParam->setDeclName(PatternParam->getDeclName());
       // If the parameter's type is not dependent, update it to match the type
       // in the pattern. They can differ in top-level cv-qualifiers, and we want
       // the pattern's type here. If the type is dependent, they can't differ,
-      // per core issue 1668. Substitute into the type from the pattern, in case
-      // it's instantiation-dependent.
+      // per core issue 1668.
       // FIXME: Updating the type to work around this is at best fragile.
-      if (!PatternDecl->getType()->isDependentType()) {
-        QualType T = S.SubstType(PatternParam->getType(), TemplateArgs,
-                                 FunctionParam->getLocation(),
-                                 FunctionParam->getDeclName());
-        if (T.isNull())
-          return true;
-        FunctionParam->setType(T);
-      }
+      if (!PatternDecl->getType()->isDependentType())
+        FunctionParam->setType(PatternParam->getType());
 
+      FunctionParam->setDeclName(PatternParam->getDeclName());
       Scope.InstantiatedLocal(PatternParam, FunctionParam);
       ++FParamIdx;
       continue;
@@ -3026,27 +3019,136 @@ static bool addInstantiatedParametersToScope(Sema &S, FunctionDecl *Function,
       = S.getNumArgumentsInExpansion(PatternParam->getType(), TemplateArgs);
     assert(NumArgumentsInExpansion &&
            "should only be called when all template arguments are known");
-    QualType PatternType =
-        PatternParam->getType()->castAs<PackExpansionType>()->getPattern();
     for (unsigned Arg = 0; Arg < *NumArgumentsInExpansion; ++Arg) {
       ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
+      if (!PatternDecl->getType()->isDependentType())
+        FunctionParam->setType(PatternParam->getType());
+
       FunctionParam->setDeclName(PatternParam->getDeclName());
-      if (!PatternDecl->getType()->isDependentType()) {
-        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(S, Arg);
-        QualType T = S.SubstType(PatternType, TemplateArgs,
-                                 FunctionParam->getLocation(),
-                                 FunctionParam->getDeclName());
+      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
+      ++FParamIdx;
+    }
+  }
+}
+
+static void InstantiateExceptionSpec(Sema &SemaRef, FunctionDecl *New,
+                                     const FunctionProtoType *Proto,
+                           const MultiLevelTemplateArgumentList &TemplateArgs) {
+  assert(Proto->getExceptionSpecType() != EST_Uninstantiated);
+
+  // C++11 [expr.prim.general]p3:
+  //   If a declaration declares a member function or member function 
+  //   template of a class X, the expression this is a prvalue of type 
+  //   "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq
+  //   and the end of the function-definition, member-declarator, or 
+  //   declarator.    
+  CXXRecordDecl *ThisContext = nullptr;
+  unsigned ThisTypeQuals = 0;
+  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(New)) {
+    ThisContext = Method->getParent();
+    ThisTypeQuals = Method->getTypeQualifiers();
+  }
+  Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, ThisTypeQuals,
+                                   SemaRef.getLangOpts().CPlusPlus11);
+
+  // The function has an exception specification or a "noreturn"
+  // attribute. Substitute into each of the exception types.
+  SmallVector<QualType, 4> Exceptions;
+  for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
+    // FIXME: Poor location information!
+    if (const PackExpansionType *PackExpansion
+          = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
+      // We have a pack expansion. Instantiate it.
+      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+      SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
+                                              Unexpanded);
+      assert(!Unexpanded.empty() &&
+             "Pack expansion without parameter packs?");
+
+      bool Expand = false;
+      bool RetainExpansion = false;
+      Optional<unsigned> NumExpansions = PackExpansion->getNumExpansions();
+      if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(),
+                                                  SourceRange(),
+                                                  Unexpanded,
+                                                  TemplateArgs,
+                                                  Expand,
+                                                  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
+        // type.
+        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
+        QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
+                                       TemplateArgs,
+                                     New->getLocation(), New->getDeclName());
         if (T.isNull())
-          return true;
-        FunctionParam->setType(T);
+          break;
+
+        T = SemaRef.Context.getPackExpansionType(T, NumExpansions);
+        Exceptions.push_back(T);
+        continue;
       }
 
-      Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);
-      ++FParamIdx;
+      // Substitute into the pack expansion pattern for each template
+      bool Invalid = false;
+      for (unsigned ArgIdx = 0; ArgIdx != *NumExpansions; ++ArgIdx) {
+        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
+
+        QualType T = SemaRef.SubstType(PackExpansion->getPattern(),
+                                       TemplateArgs,
+                                     New->getLocation(), New->getDeclName());
+        if (T.isNull()) {
+          Invalid = true;
+          break;
+        }
+
+        Exceptions.push_back(T);
+      }
+
+      if (Invalid)
+        break;
+
+      continue;
+    }
+
+    QualType T
+      = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
+                          New->getLocation(), New->getDeclName());
+    if (T.isNull() ||
+        SemaRef.CheckSpecifiedExceptionType(T, New->getLocation()))
+      continue;
+
+    Exceptions.push_back(T);
+  }
+  Expr *NoexceptExpr = nullptr;
+  if (Expr *OldNoexceptExpr = Proto->getNoexceptExpr()) {
+    EnterExpressionEvaluationContext Unevaluated(SemaRef,
+                                                 Sema::ConstantEvaluated);
+    ExprResult E = SemaRef.SubstExpr(OldNoexceptExpr, TemplateArgs);
+    if (E.isUsable())
+      E = SemaRef.CheckBooleanCondition(E.get(), E.get()->getLocStart());
+
+    if (E.isUsable()) {
+      NoexceptExpr = E.get();
+      if (!NoexceptExpr->isTypeDependent() &&
+          !NoexceptExpr->isValueDependent())
+        NoexceptExpr
+          = SemaRef.VerifyIntegerConstantExpression(NoexceptExpr,
+              nullptr, diag::err_noexcept_needs_constant_expression,
+              /*AllowFold*/ false).get();
     }
   }
 
-  return false;
+  FunctionProtoType::ExceptionSpecInfo ESI;
+  ESI.Type = Proto->getExceptionSpecType();
+  ESI.Exceptions = Exceptions;
+  ESI.NoexceptExpr = NoexceptExpr;
+
+  SemaRef.UpdateExceptionSpec(New, ESI);
 }
 
 void Sema::InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
@@ -3073,14 +3175,11 @@ void Sema::InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
     getTemplateInstantiationArgs(Decl, nullptr, /*RelativeToPrimary*/true);
 
   FunctionDecl *Template = Proto->getExceptionSpecTemplate();
-  if (addInstantiatedParametersToScope(*this, Decl, Template, Scope,
-                                       TemplateArgs)) {
-    UpdateExceptionSpec(Decl, EST_None);
-    return;
-  }
+  addInstantiatedParametersToScope(*this, Decl, Template, Scope, TemplateArgs);
 
-  SubstExceptionSpec(Decl, Template->getType()->castAs<FunctionProtoType>(),
-                     TemplateArgs);
+  ::InstantiateExceptionSpec(*this, Decl,
+                             Template->getType()->castAs<FunctionProtoType>(),
+                             TemplateArgs);
 }
 
 /// \brief Initializes the common fields of an instantiation function
@@ -3149,7 +3248,7 @@ TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
       New->setType(SemaRef.Context.getFunctionType(
           NewProto->getReturnType(), NewProto->getParamTypes(), EPI));
     } else {
-      SemaRef.SubstExceptionSpec(New, Proto, TemplateArgs);
+      ::InstantiateExceptionSpec(SemaRef, New, Proto, TemplateArgs);
     }
   }
 
@@ -3339,9 +3438,8 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
     MultiLevelTemplateArgumentList TemplateArgs =
       getTemplateInstantiationArgs(Function, nullptr, false, PatternDecl);
 
-    if (addInstantiatedParametersToScope(*this, Function, PatternDecl, Scope,
-                                         TemplateArgs))
-      return;
+    addInstantiatedParametersToScope(*this, Function, PatternDecl, Scope,
+                                     TemplateArgs);
 
     // If this is a constructor, instantiate the member initializers.
     if (const CXXConstructorDecl *Ctor =