From f8e8b5f5c29678288f1a71bd2f14a3ba6843b112 Mon Sep 17 00:00:00 2001
From: Nico Rieck <nico.rieck@gmail.com>
Date: Tue, 21 Jan 2014 23:54:36 +0000
Subject: [PATCH] Delay attribute checking until auto types are deduced

Checking in ActOnVariableDeclarator computes and caches the linkage using
the non-deduced auto type which defaults to external linkage. Depending on
how the auto type is deduced linkage can change and conflict with the
cached linkage, hitting asserts.

llvm-svn: 199774
---
 clang/lib/Sema/SemaDecl.cpp           | 7 ++++++-
 clang/test/SemaCXX/attr-selectany.cpp | 5 ++++-
 clang/test/SemaCXX/attr-weak.cpp      | 6 ++++--
 clang/test/SemaCXX/attr-weakref.cpp   | 4 +++-
 4 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f7b7ac87ec98..c08d87d59a89 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -4816,6 +4816,10 @@ bool Sema::inferObjCARCLifetime(ValueDecl *decl) {
 }
 
 static void checkAttributesAfterMerging(Sema &S, NamedDecl &ND) {
+  // Ensure that an auto decl is deduced otherwise the checks below might cache
+  // the wrong linkage.
+  assert(S.ParsingInitForAutoVars.count(&ND) == 0);
+
   // 'weak' only applies to declarations with external linkage.
   if (WeakAttr *Attr = ND.getAttr<WeakAttr>()) {
     if (!ND.isExternallyVisible()) {
@@ -5431,7 +5435,6 @@ Sema::ActOnVariableDeclarator(Scope *S, Declarator &D, DeclContext *DC,
   }
 
   ProcessPragmaWeak(S, NewVD);
-  checkAttributesAfterMerging(*this, *NewVD);
 
   // If this is the first declaration of an extern C variable, update
   // the map of such variables.
@@ -8892,6 +8895,8 @@ Sema::FinalizeDeclaration(Decl *ThisDecl) {
   if (!VD)
     return;
 
+  checkAttributesAfterMerging(*this, *VD);
+
   if (UsedAttr *Attr = VD->getAttr<UsedAttr>()) {
     if (!Attr->isInherited() && !VD->isThisDeclarationADefinition()) {
       Diag(Attr->getLocation(), diag::warn_attribute_ignored) << Attr;
diff --git a/clang/test/SemaCXX/attr-selectany.cpp b/clang/test/SemaCXX/attr-selectany.cpp
index 0f9776dbf5db..c27a9159215f 100644
--- a/clang/test/SemaCXX/attr-selectany.cpp
+++ b/clang/test/SemaCXX/attr-selectany.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fms-extensions -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fms-extensions -fsyntax-only -verify -std=c++11 %s
 // MSVC produces similar diagnostics.
 
 __declspec(selectany) void foo() { } // expected-error{{'selectany' can only be applied to data items with external linkage}}
@@ -31,3 +31,6 @@ class X {
 };
 
 __declspec(selectany) X x(1);
+
+namespace { class Internal {}; }
+__declspec(selectany) auto x8 = Internal(); // expected-error {{'selectany' can only be applied to data items with external linkage}}
diff --git a/clang/test/SemaCXX/attr-weak.cpp b/clang/test/SemaCXX/attr-weak.cpp
index 2000e7fc683b..8ba3a954282d 100644
--- a/clang/test/SemaCXX/attr-weak.cpp
+++ b/clang/test/SemaCXX/attr-weak.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fsyntax-only -verify -std=c++11 %s
 
 static int test0 __attribute__((weak)); // expected-error {{weak declaration cannot have internal linkage}}
 static void test1() __attribute__((weak)); // expected-error {{weak declaration cannot have internal linkage}}
@@ -31,8 +31,10 @@ template <class T> struct Test7 {
 };
 template <class T>
 int Test7<T>::var;
-namespace { class Internal; }
+namespace { class Internal {}; }
 template struct Test7<Internal>;
 template struct Test7<int>;
 
 class __attribute__((weak)) Test8 {}; // OK
+
+__attribute__((weak)) auto Test9 = Internal(); // expected-error {{weak declaration cannot have internal linkage}}
diff --git a/clang/test/SemaCXX/attr-weakref.cpp b/clang/test/SemaCXX/attr-weakref.cpp
index 0c3f1d20e7f7..46ca5ab20682 100644
--- a/clang/test/SemaCXX/attr-weakref.cpp
+++ b/clang/test/SemaCXX/attr-weakref.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fsyntax-only -verify -std=c++11 %s
 
 // GCC will accept anything as the argument of weakref. Should we
 // check for an existing decl?
@@ -34,3 +34,5 @@ static int a10();
 int a10() __attribute__((weakref ("foo")));
 
 static int v __attribute__((weakref(a1), alias("foo"))); // expected-error {{'weakref' attribute requires a string}}
+
+__attribute__((weakref ("foo"))) auto a11 = 1; // expected-error {{weakref declaration must have internal linkage}}