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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

llvm-svn: 312306
This commit is contained in:
Martin Storsjo 2017-09-01 06:41:55 +00:00
parent 18821b60b0
commit c6c5af75f2
3 changed files with 15 additions and 10 deletions
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16
clang/lib/CodeGen/ItaniumCXXABI.cpp
View File

@ -2998,15 +2998,13 @@ static llvm::GlobalVariable::LinkageTypes getTypeInfoLinkage(CodeGenModule &CGM,
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;

5
clang/test/CodeGenCXX/rtti-mingw64.cpp
View File

@ -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),

4
clang/test/CodeGenCXX/virt-dtor-key.cpp
View File

@ -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();