From: David Majnemer <david.majnemer@gmail.com>
Date: Tue, 21 Jun 2016 03:40:16 +0000 (+0000)
Subject: [CodeGen] Do not run initializers for imported variables
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5112212e3b8f5e8f8ea29c97ec42b8f78adae866;p=clang

[CodeGen] Do not run initializers for imported variables

The export side is responsible for running any initializers, they are
run when the module is first loaded.  Attempting to run an initializer
for the import side is not possible.

This fixes PR28216.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@273237 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGDeclCXX.cpp b/lib/CodeGen/CGDeclCXX.cpp
index 89d142e44b..8f8ffe66b6 100644
--- a/lib/CodeGen/CGDeclCXX.cpp
+++ b/lib/CodeGen/CGDeclCXX.cpp
@@ -323,6 +323,10 @@ CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
        D->hasAttr<CUDASharedAttr>()))
     return;
 
+  // DLL imported variables will be initialized by the export side.
+  if (D->hasAttr<DLLImportAttr>())
+    return;
+
   // Check if we've already initialized this decl.
   auto I = DelayedCXXInitPosition.find(D);
   if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
diff --git a/test/CodeGenCXX/PR28216.cpp b/test/CodeGenCXX/PR28216.cpp
new file mode 100644
index 0000000000..6262c87de2
--- /dev/null
+++ b/test/CodeGenCXX/PR28216.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 %s -triple i686-pc-win32 -fms-extensions -emit-llvm -o - | FileCheck %s
+
+template <typename>
+struct __declspec(dllimport) S {
+  S();
+};
+
+template <typename T>
+struct __declspec(dllimport) U {
+  static S<T> u;
+};
+
+template <typename T>
+S<T> U<T>::u;
+
+template S<int> U<int>::u;
+// CHECK-NOT: define internal void @"\01??__Eu@?$U@H@@2U?$S@H@@A@YAXXZ"(
+
+S<int> &i = U<int>::u;