r312306 - Reland r312224 - [ItaniumCXXABI] Always use linkonce_odr linkage for RTTI data on MinGW

[Martin Storsjo via cfe-commits]

Author: mstorsjo
Date: Thu Aug 31 23:41:55 2017
New Revision: 312306

URL: http://llvm.org/viewvc/llvm-project?rev=312306&view=rev
Log:
Reland r312224 - [ItaniumCXXABI] Always use linkonce_odr linkage for RTTI data on MinGW

This fixes cases where dynamic classes produced RTTI data with
external linkage, producing linker errors about duplicate symbols.

This touches code close to what was changed in SVN r244266, but
this change doesn't break the tests added in that revision.

The previous version had missed to update CodeGenCXX/virt-dtor-key.cpp,
which had a behaviour change only when running the testsuite on windows.

Differential revision: https://reviews.llvm.org/D37327

Modified:
    cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
    cfe/trunk/test/CodeGenCXX/rtti-mingw64.cpp
    cfe/trunk/test/CodeGenCXX/virt-dtor-key.cpp

Modified: cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp?rev=312306&r1=312305&r2=312306&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp (original)
+++ cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp Thu Aug 31 23:41:55 2017
@@ -2998,15 +2998,13 @@ static llvm::GlobalVariable::LinkageType
         if (RD->hasAttr<DLLImportAttr>() &&
             ShouldUseExternalRTTIDescriptor(CGM, Ty))
           return llvm::GlobalValue::ExternalLinkage;
-      if (RD->isDynamicClass()) {
-        llvm::GlobalValue::LinkageTypes LT = CGM.getVTableLinkage(RD);
-        // MinGW won't export the RTTI information when there is a key function.
-        // Make sure we emit our own copy instead of attempting to dllimport it.
-        if (RD->hasAttr<DLLImportAttr>() &&
-            llvm::GlobalValue::isAvailableExternallyLinkage(LT))
-          LT = llvm::GlobalValue::LinkOnceODRLinkage;
-        return LT;
-      }
+      // MinGW always uses LinkOnceODRLinkage for type info.
+      if (RD->isDynamicClass() &&
+          !CGM.getContext()
+               .getTargetInfo()
+               .getTriple()
+               .isWindowsGNUEnvironment())
+        return CGM.getVTableLinkage(RD);
     }
 
     return llvm::GlobalValue::LinkOnceODRLinkage;

Modified: cfe/trunk/test/CodeGenCXX/rtti-mingw64.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/rtti-mingw64.cpp?rev=312306&r1=312305&r2=312306&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/rtti-mingw64.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/rtti-mingw64.cpp Thu Aug 31 23:41:55 2017
@@ -2,7 +2,12 @@
 struct A { int a; };
 struct B : virtual A { int b; };
 B b;
+class C {
+  virtual ~C();
+};
+C::~C() {}
 
+// CHECK: @_ZTI1C = linkonce_odr
 // CHECK: @_ZTI1B = linkonce_odr constant { i8*, i8*, i32, i32, i8*, i64 }
 // CHECK-SAME:  i8* bitcast (i8** getelementptr inbounds (i8*, i8** @_ZTVN10__cxxabiv121__vmi_class_type_infoE, i64 2) to i8*),
 // CHECK-SAME:  i8* getelementptr inbounds ([3 x i8], [3 x i8]* @_ZTS1B, i32 0, i32 0),

Modified: cfe/trunk/test/CodeGenCXX/virt-dtor-key.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/virt-dtor-key.cpp?rev=312306&r1=312305&r2=312306&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/virt-dtor-key.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/virt-dtor-key.cpp Thu Aug 31 23:41:55 2017
@@ -1,5 +1,7 @@
-// RUN: %clang_cc1 -triple %itanium_abi_triple -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple i386-linux -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple i386-windows-gnu -emit-llvm %s -o - | FileCheck %s -check-prefix CHECK-MINGW
 // CHECK: @_ZTI3foo = constant
+// CHECK-MINGW: @_ZTI3foo = linkonce_odr
 class foo {
    foo();
    virtual ~foo();