From: Yaron Keren <yaron.keren@gmail.com>
Date: Fri, 22 Jan 2016 19:03:27 +0000 (+0000)
Subject: Merge templated static member variables, fixes http://llvm.org/pr26179.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ea5b0ddd89b0b681d410714cbcd20fcd713dcf05;p=clang

Merge templated static member variables, fixes http://llvm.org/pr26179.

Patch by Vassil Vassilev!
Reviewed by Richard Smith.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@258524 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index 5bf95f878d..9bcd9a0164 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -2595,8 +2595,24 @@ static bool isSameEntity(NamedDecl *X, NamedDecl *Y) {
   // Variables with the same type and linkage match.
   if (VarDecl *VarX = dyn_cast<VarDecl>(X)) {
     VarDecl *VarY = cast<VarDecl>(Y);
-    return (VarX->getLinkageInternal() == VarY->getLinkageInternal()) &&
-      VarX->getASTContext().hasSameType(VarX->getType(), VarY->getType());
+    if (VarX->getLinkageInternal() == VarY->getLinkageInternal()) {
+      ASTContext &C = VarX->getASTContext();
+      if (C.hasSameType(VarX->getType(), VarY->getType()))
+        return true;
+
+      // We can get decls with different types on the redecl chain. Eg.
+      // template <typename T> struct S { static T Var[]; }; // #1
+      // template <typename T> T S<T>::Var[sizeof(T)]; // #2
+      // Only? happens when completing an incomplete array type. In this case
+      // when comparing #1 and #2 we should go through their elements types.
+      const ArrayType *VarXTy = C.getAsArrayType(VarX->getType());
+      const ArrayType *VarYTy = C.getAsArrayType(VarY->getType());
+      if (!VarXTy || !VarYTy)
+        return false;
+      if (VarXTy->isIncompleteArrayType() || VarYTy->isIncompleteArrayType())
+        return C.hasSameType(VarXTy->getElementType(), VarYTy->getElementType());
+    }
+    return false;
   }
 
   // Namespaces with the same name and inlinedness match.
diff --git a/test/Modules/Inputs/PR26179/A.h b/test/Modules/Inputs/PR26179/A.h
new file mode 100644
index 0000000000..ce95fafb4b
--- /dev/null
+++ b/test/Modules/Inputs/PR26179/A.h
@@ -0,0 +1,4 @@
+#include "basic_string.h"
+#include "B.h"
+
+int *p = a;
diff --git a/test/Modules/Inputs/PR26179/B.h b/test/Modules/Inputs/PR26179/B.h
new file mode 100644
index 0000000000..eb8d1c29e7
--- /dev/null
+++ b/test/Modules/Inputs/PR26179/B.h
@@ -0,0 +1,2 @@
+#include "basic_string.h"
+extern int a[5];
diff --git a/test/Modules/Inputs/PR26179/basic_string.h b/test/Modules/Inputs/PR26179/basic_string.h
new file mode 100644
index 0000000000..afd1e0d3b3
--- /dev/null
+++ b/test/Modules/Inputs/PR26179/basic_string.h
@@ -0,0 +1,14 @@
+#ifndef _GLIBCXX_STRING
+#define _GLIBCXX_STRING 1
+
+template<typename T>
+struct basic_string {
+  static T _S_empty_rep_storage[];
+};
+
+template<typename T>
+T basic_string<T>::_S_empty_rep_storage[sizeof(T)];
+
+extern int a[];
+
+#endif
diff --git a/test/Modules/Inputs/PR26179/module.modulemap b/test/Modules/Inputs/PR26179/module.modulemap
new file mode 100644
index 0000000000..49374181d7
--- /dev/null
+++ b/test/Modules/Inputs/PR26179/module.modulemap
@@ -0,0 +1,9 @@
+module A {
+  header "A.h"
+  export *
+}
+
+module B {
+  header "B.h"
+  export *
+}
diff --git a/test/Modules/pr26179.cpp b/test/Modules/pr26179.cpp
new file mode 100644
index 0000000000..f25f1ce24b
--- /dev/null
+++ b/test/Modules/pr26179.cpp
@@ -0,0 +1,7 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -I%S/Inputs/PR26179 -verify %s
+// RUN: %clang_cc1 -fmodules -fmodule-map-file=%S/Inputs/PR26179/module.modulemap -fmodules-cache-path=%t -I%S/Inputs/PR26179 -verify %s
+
+#include "A.h"
+
+// expected-no-diagnostics