From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Wed, 1 Jul 2015 23:19:58 +0000 (+0000)
Subject: [modules] Merging support for specializations of a function template. This very
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4107de1e702486e7f06c9622b2343ccfa4d0661a;p=clang

[modules] Merging support for specializations of a function template. This very
rarely matters, but can affect whether two dependent types are canonically
equivalent.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@241207 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index c89140dcaf..b23c33c551 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -810,14 +810,14 @@ void ASTDeclReader::VisitFunctionDecl(FunctionDecl *FD) {
       FunctionTemplateSpecializationInfo::Profile(ID, TemplArgs, C);
       void *InsertPos = nullptr;
       FunctionTemplateDecl::Common *CommonPtr = CanonTemplate->getCommonPtr();
-      CommonPtr->Specializations.FindNodeOrInsertPos(ID, InsertPos);
+      FunctionTemplateSpecializationInfo *ExistingInfo =
+          CommonPtr->Specializations.FindNodeOrInsertPos(ID, InsertPos);
       if (InsertPos)
         CommonPtr->Specializations.InsertNode(FTInfo, InsertPos);
       else {
         assert(Reader.getContext().getLangOpts().Modules &&
                "already deserialized this template specialization");
-        // FIXME: This specialization is a redeclaration of one from another
-        // module. Merge it.
+        mergeRedeclarable(FD, ExistingInfo->Function, Redecl);
       }
     }
     break;
@@ -839,8 +839,8 @@ void ASTDeclReader::VisitFunctionDecl(FunctionDecl *FD) {
     
     FD->setDependentTemplateSpecialization(Reader.getContext(),
                                            TemplDecls, TemplArgs);
-
-    // FIXME: Merging.
+    // These are not merged; we don't need to merge redeclarations of dependent
+    // template friends.
     break;
   }
   }
diff --git a/test/Modules/Inputs/submodules-merge-defs/defs.h b/test/Modules/Inputs/submodules-merge-defs/defs.h
index bf720aaba3..bda0567c93 100644
--- a/test/Modules/Inputs/submodules-merge-defs/defs.h
+++ b/test/Modules/Inputs/submodules-merge-defs/defs.h
@@ -86,3 +86,11 @@ namespace SeparateInline {
 namespace TrailingAttributes {
   template<typename T> struct X {} __attribute__((aligned(8)));
 }
+
+namespace MergeFunctionTemplateSpecializations {
+  template<typename T> T f();
+  template<typename T> struct X {
+    template<typename U> using Q = decltype(f<T>() + U());
+  };
+  using xiq = X<int>::Q<int>;
+}
diff --git a/test/Modules/submodules-merge-defs.cpp b/test/Modules/submodules-merge-defs.cpp
index 2e771c1562..92c784440b 100644
--- a/test/Modules/submodules-merge-defs.cpp
+++ b/test/Modules/submodules-merge-defs.cpp
@@ -100,6 +100,8 @@ J<> post_j2;
 FriendDefArg::Y<int> friend_def_arg;
 FriendDefArg::D<> friend_def_arg_d;
 
+MergeFunctionTemplateSpecializations::X<int>::Q<char> xiqc;
+
 #ifdef TEXTUAL
 #include "use-defs.h"
 void use_static_inline() { StaticInline::g({}); }