Hi rnk, majnemer,
This patch makes us emit dllexported in-class initialized static data members
(which are treated as definitions in the MS ABI), even when they're not
referenced.
It also makes their special linkage reflected in the GVA linkage instead of
getting massaged in CodeGen.
Please take a look!
http://reviews.llvm.org/D4563
Files:
include/clang/AST/ASTContext.h
lib/AST/ASTContext.cpp
lib/CodeGen/CGCXXABI.h
lib/CodeGen/CodeGenModule.cpp
lib/CodeGen/MicrosoftCXXABI.cpp
lib/CodeGen/ModuleBuilder.cpp
test/CodeGenCXX/ms-integer-static-data-members-exported.cpp
Index: include/clang/AST/ASTContext.h
===================================================================
--- include/clang/AST/ASTContext.h
+++ include/clang/AST/ASTContext.h
@@ -2283,6 +2283,10 @@
void getObjCEncodingForMethodParameter(Decl::ObjCDeclQualifier QT,
QualType T, std::string& S,
bool Extended) const;
+
+ /// \brief Returns true if this is an inline-initialized static data member
+ /// which the MS ABI treats as a definition.
+ bool isMSStaticDataMemberInlineDefinition(const VarDecl *VD) const;
private:
const ASTRecordLayout &
Index: lib/AST/ASTContext.cpp
===================================================================
--- lib/AST/ASTContext.cpp
+++ lib/AST/ASTContext.cpp
@@ -4781,6 +4781,14 @@
return sz;
}
+bool ASTContext::isMSStaticDataMemberInlineDefinition(const VarDecl *VD) const {
+ return VD->isStaticDataMember() &&
+ VD->getType()->isIntegralOrEnumerationType() &&
+ getTargetInfo().getCXXABI().isMicrosoft() &&
+ !VD->getFirstDecl()->isOutOfLine() &&
+ VD->getFirstDecl()->hasInit();
+}
+
static inline
std::string charUnitsToString(const CharUnits &CU) {
return llvm::itostr(CU.getQuantity());
@@ -7849,6 +7857,12 @@
: StaticLocalLinkage;
}
+ // MSVC treats in-class initialized static data members as definitions.
+ // By giving them non-strong linkage, out-of-line definitions won't
+ // cause link errors.
+ if (Context.isMSStaticDataMemberInlineDefinition(VD))
+ return GVA_DiscardableODR;
+
switch (VD->getTemplateSpecializationKind()) {
case TSK_Undeclared:
case TSK_ExplicitSpecialization:
@@ -7934,7 +7948,8 @@
const VarDecl *VD = cast<VarDecl>(D);
assert(VD->isFileVarDecl() && "Expected file scoped var");
- if (VD->isThisDeclarationADefinition() == VarDecl::DeclarationOnly)
+ if (VD->isThisDeclarationADefinition() == VarDecl::DeclarationOnly &&
+ !isMSStaticDataMemberInlineDefinition(VD))
return false;
// Variables that can be needed in other TUs are required.
Index: lib/CodeGen/CGCXXABI.h
===================================================================
--- lib/CodeGen/CGCXXABI.h
+++ lib/CodeGen/CGCXXABI.h
@@ -403,10 +403,6 @@
/// Gets the deleted virtual member call name.
virtual StringRef GetDeletedVirtualCallName() = 0;
- /// \brief Returns true iff static data members that are initialized in the
- /// class definition should have linkonce linkage.
- virtual bool isInlineInitializedStaticDataMemberLinkOnce() { return false; }
-
/**************************** Array cookies ******************************/
/// Returns the extra size required in order to store the array
Index: lib/CodeGen/CodeGenModule.cpp
===================================================================
--- lib/CodeGen/CodeGenModule.cpp
+++ lib/CodeGen/CodeGenModule.cpp
@@ -1256,7 +1256,8 @@
const auto *VD = cast<VarDecl>(Global);
assert(VD->isFileVarDecl() && "Cannot emit local var decl as global.");
- if (VD->isThisDeclarationADefinition() != VarDecl::Definition)
+ if (VD->isThisDeclarationADefinition() != VarDecl::Definition &&
+ !Context.isMSStaticDataMemberInlineDefinition(VD))
return;
}
@@ -1592,18 +1593,6 @@
return true;
}
-static bool isVarDeclInlineInitializedStaticDataMember(const VarDecl *VD) {
- if (!VD->isStaticDataMember())
- return false;
- const VarDecl *InitDecl;
- const Expr *InitExpr = VD->getAnyInitializer(InitDecl);
- if (!InitExpr)
- return false;
- if (InitDecl->isThisDeclarationADefinition())
- return false;
- return true;
-}
-
/// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module,
/// create and return an llvm GlobalVariable with the specified type. If there
/// is something in the module with the specified name, return it potentially
@@ -1666,9 +1655,9 @@
// If required by the ABI, treat declarations of static data members with
// inline initializers as definitions.
- if (getCXXABI().isInlineInitializedStaticDataMemberLinkOnce() &&
- isVarDeclInlineInitializedStaticDataMember(D))
+ if (getContext().isMSStaticDataMemberInlineDefinition(D)) {
EmitGlobalVarDefinition(D);
+ }
// Handle XCore specific ABI requirements.
if (getTarget().getTriple().getArch() == llvm::Triple::xcore &&
@@ -2087,18 +2076,6 @@
return !Context.getLangOpts().AppleKext ? llvm::Function::WeakODRLinkage
: llvm::Function::ExternalLinkage;
- // If required by the ABI, give definitions of static data members with inline
- // initializers at least linkonce_odr linkage.
- auto const VD = dyn_cast<VarDecl>(D);
- if (getCXXABI().isInlineInitializedStaticDataMemberLinkOnce() &&
- VD && isVarDeclInlineInitializedStaticDataMember(VD)) {
- if (VD->hasAttr<DLLImportAttr>())
- return llvm::GlobalValue::AvailableExternallyLinkage;
- if (VD->hasAttr<DLLExportAttr>())
- return llvm::GlobalValue::WeakODRLinkage;
- return llvm::GlobalValue::LinkOnceODRLinkage;
- }
-
// C++ doesn't have tentative definitions and thus cannot have common
// linkage.
if (!getLangOpts().CPlusPlus && isa<VarDecl>(D) &&
Index: lib/CodeGen/MicrosoftCXXABI.cpp
===================================================================
--- lib/CodeGen/MicrosoftCXXABI.cpp
+++ lib/CodeGen/MicrosoftCXXABI.cpp
@@ -55,8 +55,6 @@
// arbitrary.
StringRef GetDeletedVirtualCallName() override { return "_purecall"; }
- bool isInlineInitializedStaticDataMemberLinkOnce() override { return true; }
-
llvm::Value *adjustToCompleteObject(CodeGenFunction &CGF,
llvm::Value *ptr,
QualType type) override;
Index: lib/CodeGen/ModuleBuilder.cpp
===================================================================
--- lib/CodeGen/ModuleBuilder.cpp
+++ lib/CodeGen/ModuleBuilder.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "clang/CodeGen/ModuleBuilder.h"
+#include "CGCXXABI.h"
#include "CGDebugInfo.h"
#include "CodeGenModule.h"
#include "clang/AST/ASTContext.h"
@@ -128,6 +129,19 @@
return;
Builder->UpdateCompletedType(D);
+
+ // If required by the ABI, treat declarations of static data members with
+ // inline initializers as definitions.
+ if (Ctx->getTargetInfo().getCXXABI().isMicrosoft()) {
+ for (Decl *Member : D->decls()) {
+ if (VarDecl *VD = dyn_cast<VarDecl>(Member)) {
+ if (Ctx->isMSStaticDataMemberInlineDefinition(VD) &&
+ Ctx->DeclMustBeEmitted(VD)) {
+ Builder->EmitGlobal(VD);
+ }
+ }
+ }
+ }
}
void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
Index: test/CodeGenCXX/ms-integer-static-data-members-exported.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/ms-integer-static-data-members-exported.cpp
@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -emit-llvm -triple=i386-pc-win32 %s -o - | FileCheck %s
+
+enum Enum { zero, one, two };
+
+struct __declspec(dllexport) S {
+ // In the MS ABI, this counts as a definition.
+ // Since it is exported, it must be emitted even if it's unreferenced.
+ static const short x = 42;
+
+ // This works for enums too.
+ static const Enum y = two;
+
+ struct NonExported {
+ // dllexport is not inherited by this nested class.
+ // Since z is not referenced, it should not be emitted.
+ static const int z = 42;
+ };
+};
+
+// CHECK: @"\01?x@S@@2FB" = weak_odr dllexport constant i16 42, align 2
+// CHECK: @"\01?y@S@@2W4Enum@@B" = weak_odr dllexport constant i32 2, align 4
+// CHECK-NOT: NonExported
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