From c8c1a1961a459f5f79ba8dfb08a2d53d5443bf32 Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Tue, 20 Dec 2016 21:35:28 +0000
Subject: [c++1z] P0195R2: Support pack-expansion of using-declarations.

This change introduces UsingPackDecl as a marker for the set of UsingDecls
produced by pack expansion of a single (unresolved) using declaration. This is
not strictly necessary (we just need to be able to map from the original using
declaration to its expansions somehow), but it's useful to maintain the
invariant that each declaration reference instantiates to refer to one
declaration.

This is a re-commit of r290080 (reverted in r290092) with a fix for a
use-after-lifetime bug.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@290203 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/AST/DeclCXX.cpp | 36 ++++++++++++++++++++++++++++++------
 1 file changed, 30 insertions(+), 6 deletions(-)

(limited to 'lib/AST/DeclCXX.cpp')

diff --git a/lib/AST/DeclCXX.cpp b/lib/AST/DeclCXX.cpp
index 8563416a48..1860b948d6 100644
--- a/lib/AST/DeclCXX.cpp
+++ b/lib/AST/DeclCXX.cpp
@@ -2250,15 +2250,37 @@ SourceRange UsingDecl::getSourceRange() const {
   return SourceRange(Begin, getNameInfo().getEndLoc());
 }
 
+void UsingPackDecl::anchor() { }
+
+UsingPackDecl *UsingPackDecl::Create(ASTContext &C, DeclContext *DC,
+                                     NamedDecl *InstantiatedFrom,
+                                     ArrayRef<NamedDecl *> UsingDecls) {
+  size_t Extra = additionalSizeToAlloc<NamedDecl *>(UsingDecls.size());
+  return new (C, DC, Extra) UsingPackDecl(DC, InstantiatedFrom, UsingDecls);
+}
+
+UsingPackDecl *UsingPackDecl::CreateDeserialized(ASTContext &C, unsigned ID,
+                                                 unsigned NumExpansions) {
+  size_t Extra = additionalSizeToAlloc<NamedDecl *>(NumExpansions);
+  auto *Result = new (C, ID, Extra) UsingPackDecl(nullptr, nullptr, None);
+  Result->NumExpansions = NumExpansions;
+  auto *Trail = Result->getTrailingObjects<NamedDecl *>();
+  for (unsigned I = 0; I != NumExpansions; ++I)
+    new (Trail + I) NamedDecl*(nullptr);
+  return Result;
+}
+
 void UnresolvedUsingValueDecl::anchor() { }
 
 UnresolvedUsingValueDecl *
 UnresolvedUsingValueDecl::Create(ASTContext &C, DeclContext *DC,
                                  SourceLocation UsingLoc,
                                  NestedNameSpecifierLoc QualifierLoc,
-                                 const DeclarationNameInfo &NameInfo) {
+                                 const DeclarationNameInfo &NameInfo,
+                                 SourceLocation EllipsisLoc) {
   return new (C, DC) UnresolvedUsingValueDecl(DC, C.DependentTy, UsingLoc,
-                                              QualifierLoc, NameInfo);
+                                              QualifierLoc, NameInfo,
+                                              EllipsisLoc);
 }
 
 UnresolvedUsingValueDecl *
@@ -2266,7 +2288,8 @@ UnresolvedUsingValueDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
   return new (C, ID) UnresolvedUsingValueDecl(nullptr, QualType(),
                                               SourceLocation(),
                                               NestedNameSpecifierLoc(),
-                                              DeclarationNameInfo());
+                                              DeclarationNameInfo(),
+                                              SourceLocation());
 }
 
 SourceRange UnresolvedUsingValueDecl::getSourceRange() const {
@@ -2283,17 +2306,18 @@ UnresolvedUsingTypenameDecl::Create(ASTContext &C, DeclContext *DC,
                                     SourceLocation TypenameLoc,
                                     NestedNameSpecifierLoc QualifierLoc,
                                     SourceLocation TargetNameLoc,
-                                    DeclarationName TargetName) {
+                                    DeclarationName TargetName,
+                                    SourceLocation EllipsisLoc) {
   return new (C, DC) UnresolvedUsingTypenameDecl(
       DC, UsingLoc, TypenameLoc, QualifierLoc, TargetNameLoc,
-      TargetName.getAsIdentifierInfo());
+      TargetName.getAsIdentifierInfo(), EllipsisLoc);
 }
 
 UnresolvedUsingTypenameDecl *
 UnresolvedUsingTypenameDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
   return new (C, ID) UnresolvedUsingTypenameDecl(
       nullptr, SourceLocation(), SourceLocation(), NestedNameSpecifierLoc(),
-      SourceLocation(), nullptr);
+      SourceLocation(), nullptr, SourceLocation());
 }
 
 void StaticAssertDecl::anchor() { }
-- 
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