From 52604ab71a74b8ec481255dfeea7dc9dba63b1a5 Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Fri, 11 Sep 2009 21:19:12 +0000
Subject: Slight improvement for extern templates, so that an explicit
 instantiation definition can follow an explicit instantiation declaration.
 This is as far as I want to go with extern templates now, but they will still
 need quite a bit more work to get all of the C++0x semantics right.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@81573 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaTemplateInstantiate.cpp | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

(limited to 'lib/Sema/SemaTemplateInstantiate.cpp')

diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index 6a5235229a..adc8a94e51 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -820,11 +820,28 @@ Sema::InstantiateClassTemplateSpecialization(
   ClassTemplateSpec = cast<ClassTemplateSpecializationDecl>(
                                          ClassTemplateSpec->getCanonicalDecl());
 
-  // We can only instantiate something that hasn't already been
-  // instantiated or specialized. Fail without any diagnostics: our
-  // caller will provide an error message.
-  if (ClassTemplateSpec->getSpecializationKind() != TSK_Undeclared)
+  // Check whether we have already instantiated or specialized this class
+  // template specialization.
+  if (ClassTemplateSpec->getSpecializationKind() != TSK_Undeclared) {
+    if (ClassTemplateSpec->getSpecializationKind() == 
+          TSK_ExplicitInstantiationDeclaration &&
+        TSK == TSK_ExplicitInstantiationDefinition) {
+      // An explicit instantiation definition follows an explicit instantiation
+      // declaration (C++0x [temp.explicit]p10); go ahead and perform the
+      // explicit instantiation.
+      ClassTemplateSpec->setSpecializationKind(TSK);
+      InstantiateClassTemplateSpecializationMembers(
+                        /*FIXME?*/ClassTemplateSpec->getPointOfInstantiation(), 
+                                  ClassTemplateSpec,
+                                  TSK);
+      return false;
+    }
+    
+    // We can only instantiate something that hasn't already been
+    // instantiated or specialized. Fail without any diagnostics: our
+    // caller will provide an error message.    
     return true;
+  }
 
   ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate();
   CXXRecordDecl *Pattern = 0;
-- 
cgit v1.2.3-70-g09d2