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When an entity is marked with both dllimport and
exclude_from_explicit_instantiation,
the compiler should not assume that the entity will be provided in another TU.
Fixes https://github.com/llvm/llvm-project/issues/40363
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D155713
Files:
clang/lib/AST/ASTContext.cpp
clang/lib/CodeGen/CodeGenModule.cpp
clang/lib/Sema/Sema.cpp
clang/test/CodeGenCXX/attr-exclude_from_explicit_instantiation.dllimport.cpp
clang/test/SemaCXX/attr-exclude_from_explicit_instantiation.dllimport.cpp
Index: clang/test/SemaCXX/attr-exclude_from_explicit_instantiation.dllimport.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/attr-exclude_from_explicit_instantiation.dllimport.cpp
@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-windows -fms-extensions -verify %s
+
+// Test that an entity marked as both dllimport and exclude_from_explicit_instantiation
+// isn't instantiated.
+
+#define DLLIMPORT __declspec(dllimport)
+#define EXCLUDE_FROM_EXPLICIT_INSTANTIATION __attribute__((exclude_from_explicit_instantiation))
+
+template <class T>
+struct DLLIMPORT Foo {
+ EXCLUDE_FROM_EXPLICIT_INSTANTIATION void x();
+};
+
+template <class T>
+struct Bar {
+ DLLIMPORT EXCLUDE_FROM_EXPLICIT_INSTANTIATION inline void x();
+};
+
+template <class T>
+void Foo<T>::x() { using Fail = typename T::fail; }
+
+template <class T>
+DLLIMPORT inline void Bar<T>::x() { using Fail = typename T::fail; }
+
+// expected-no-diagnostics
+template struct Foo<int>;
+template struct Bar<int>;
Index: clang/test/CodeGenCXX/attr-exclude_from_explicit_instantiation.dllimport.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/attr-exclude_from_explicit_instantiation.dllimport.cpp
@@ -0,0 +1,32 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-windows -fms-extensions -emit-llvm -O0 -o - %s | FileCheck %s
+
+// Test that dllimport and exclude_from_explicit_instantiation work properly
+// together. Specifically, we check that when exclude_from_explicit_instantiation
+// is used on a method, the compiler doesn't expect it to be provided externally
+// even if it is marked with dllimport.
+//
+// https://github.com/llvm/llvm-project/issues/40363
+
+#define DLLIMPORT __declspec(dllimport)
+#define EXCLUDE_FROM_EXPLICIT_INSTANTIATION __attribute__((exclude_from_explicit_instantiation))
+
+template <class T>
+struct DLLIMPORT Foo {
+ EXCLUDE_FROM_EXPLICIT_INSTANTIATION void x() {}
+};
+
+template <class T>
+struct Bar {
+ DLLIMPORT EXCLUDE_FROM_EXPLICIT_INSTANTIATION void x() {}
+};
+
+extern template struct Foo<int>;
+extern template struct Bar<int>;
+
+void test(Foo<int>& foo, Bar<int>& bar) {
+ // CHECK-DAG: define linkonce_odr dso_local void @"?x@?$Foo@H@@QEAAXXZ"
+ foo.x();
+
+ // CHECK-DAG: define linkonce_odr dso_local void @"?x@?$Bar@H@@QEAAXXZ"
+ bar.x();
+}
Index: clang/lib/Sema/Sema.cpp
===================================================================
--- clang/lib/Sema/Sema.cpp
+++ clang/lib/Sema/Sema.cpp
@@ -818,10 +818,13 @@
if (isa<CXXDeductionGuideDecl>(ND))
continue;
- if (ND->hasAttr<DLLImportAttr>() || ND->hasAttr<DLLExportAttr>()) {
+ if ((ND->hasAttr<DLLImportAttr>() || ND->hasAttr<DLLExportAttr>()) &&
+ !ND->hasAttr<ExcludeFromExplicitInstantiationAttr>()) {
// An exported function will always be emitted when defined, so even if
// the function is inline, it doesn't have to be emitted in this TU. An
- // imported function implies that it has been exported somewhere else.
+ // imported function implies that it has been exported somewhere else,
+ // except if it is marked with exclude_from_explicit_instantiation, in
+ // which case there might not be a definition elsewhere.
continue;
}
Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -1512,7 +1512,7 @@
void CodeGenModule::setDLLImportDLLExport(llvm::GlobalValue *GV,
const NamedDecl *D) const {
- if (D && D->isExternallyVisible()) {
+ if (D && D->isExternallyVisible() && !D->hasAttr<ExcludeFromExplicitInstantiationAttr>()) {
if (D->hasAttr<DLLImportAttr>())
GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
else if ((D->hasAttr<DLLExportAttr>() ||
Index: clang/lib/AST/ASTContext.cpp
===================================================================
--- clang/lib/AST/ASTContext.cpp
+++ clang/lib/AST/ASTContext.cpp
@@ -11696,7 +11696,7 @@
const Decl *D, GVALinkage L) {
// See http://msdn.microsoft.com/en-us/library/xa0d9ste.aspx
// dllexport/dllimport on inline functions.
- if (D->hasAttr<DLLImportAttr>()) {
+ if (D->hasAttr<DLLImportAttr>() && !D->hasAttr<ExcludeFromExplicitInstantiationAttr>()) {
if (L == GVA_DiscardableODR || L == GVA_StrongODR)
return GVA_AvailableExternally;
} else if (D->hasAttr<DLLExportAttr>()) {
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