[clang] 18f3bcb - [C++20] [Modules] Correct the linkage for template instantiations in
Chuanqi Xu via cfe-commits
cfe-commits at lists.llvm.org
Mon Jul 1 20:44:42 PDT 2024
Author: Chuanqi Xu
Date: 2024-07-02T11:43:26+08:00
New Revision: 18f3bcbb13ca83d33223b00761d8cddf463e9ffb
URL: https://github.com/llvm/llvm-project/commit/18f3bcbb13ca83d33223b00761d8cddf463e9ffb
DIFF: https://github.com/llvm/llvm-project/commit/18f3bcbb13ca83d33223b00761d8cddf463e9ffb.diff
LOG: [C++20] [Modules] Correct the linkage for template instantiations in
named modules
Close https://github.com/llvm/llvm-project/issues/97313
In the previous patch (https://github.com/llvm/llvm-project/pull/75912),
I made an oversight that I ignored the templates in named module when
calculating the linkage for the vtables. In this patch, I tried to
correct the behavior by merging the logics to calculate the linkage with
key functions with named modules.
Added:
clang/test/Modules/pr97313.cppm
Modified:
clang/lib/CodeGen/CGVTables.cpp
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CGVTables.cpp b/clang/lib/CodeGen/CGVTables.cpp
index 3e88cd73e8c1f..10d972ec8a362 100644
--- a/clang/lib/CodeGen/CGVTables.cpp
+++ b/clang/lib/CodeGen/CGVTables.cpp
@@ -1079,33 +1079,38 @@ CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) {
if (!RD->isExternallyVisible())
return llvm::GlobalVariable::InternalLinkage;
- // V-tables for non-template classes with an owning module are always
- // uniquely emitted in that module.
- if (RD->isInNamedModule())
- return llvm::GlobalVariable::ExternalLinkage;
-
- // We're at the end of the translation unit, so the current key
- // function is fully correct.
- const CXXMethodDecl *keyFunction = Context.getCurrentKeyFunction(RD);
- if (keyFunction && !RD->hasAttr<DLLImportAttr>()) {
+ bool IsInNamedModule = RD->isInNamedModule();
+ // If the CXXRecordDecl are not in a module unit, we need to get
+ // its key function. We're at the end of the translation unit, so the current
+ // key function is fully correct.
+ const CXXMethodDecl *keyFunction =
+ IsInNamedModule ? nullptr : Context.getCurrentKeyFunction(RD);
+ if (IsInNamedModule || (keyFunction && !RD->hasAttr<DLLImportAttr>())) {
// If this class has a key function, use that to determine the
// linkage of the vtable.
const FunctionDecl *def = nullptr;
- if (keyFunction->hasBody(def))
+ if (keyFunction && keyFunction->hasBody(def))
keyFunction = cast<CXXMethodDecl>(def);
- switch (keyFunction->getTemplateSpecializationKind()) {
- case TSK_Undeclared:
- case TSK_ExplicitSpecialization:
+ bool IsExternalDefinition =
+ IsInNamedModule ? RD->shouldEmitInExternalSource() : !def;
+
+ TemplateSpecializationKind Kind =
+ IsInNamedModule ? RD->getTemplateSpecializationKind()
+ : keyFunction->getTemplateSpecializationKind();
+
+ switch (Kind) {
+ case TSK_Undeclared:
+ case TSK_ExplicitSpecialization:
assert(
- (def || CodeGenOpts.OptimizationLevel > 0 ||
+ (IsInNamedModule || def || CodeGenOpts.OptimizationLevel > 0 ||
CodeGenOpts.getDebugInfo() != llvm::codegenoptions::NoDebugInfo) &&
- "Shouldn't query vtable linkage without key function, "
- "optimizations, or debug info");
- if (!def && CodeGenOpts.OptimizationLevel > 0)
+ "Shouldn't query vtable linkage without the class in module units, "
+ "key function, optimizations, or debug info");
+ if (IsExternalDefinition && CodeGenOpts.OptimizationLevel > 0)
return llvm::GlobalVariable::AvailableExternallyLinkage;
- if (keyFunction->isInlined())
+ if (keyFunction && keyFunction->isInlined())
return !Context.getLangOpts().AppleKext
? llvm::GlobalVariable::LinkOnceODRLinkage
: llvm::Function::InternalLinkage;
@@ -1124,7 +1129,7 @@ CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) {
case TSK_ExplicitInstantiationDeclaration:
llvm_unreachable("Should not have been asked to emit this");
- }
+ }
}
// -fapple-kext mode does not support weak linkage, so we must use
diff --git a/clang/test/Modules/pr97313.cppm b/clang/test/Modules/pr97313.cppm
new file mode 100644
index 0000000000000..ebbd0ee4e2c65
--- /dev/null
+++ b/clang/test/Modules/pr97313.cppm
@@ -0,0 +1,118 @@
+// REQUIRES: !system-windows
+//
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: split-file %s %t
+//
+// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple %t/Base.cppm \
+// RUN: -emit-module-interface -o %t/Base.pcm
+// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple %t/Sub.cppm \
+// RUN: -emit-module-interface -o %t/Sub.pcm -fprebuilt-module-path=%t
+// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple %t/Sub.pcm \
+// RUN: -emit-llvm -o %t/Sub.pcm -o - -fprebuilt-module-path=%t | \
+// RUN: FileCheck %t/Sub.cppm
+// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple %t/main.cpp \
+// RUN: -emit-llvm -fprebuilt-module-path=%t -o - | FileCheck %t/main.cpp
+//
+// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple %t/Mod.cppm \
+// RUN: -emit-module-interface -o %t/Mod.pcm
+// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple %t/Mod.pcm \
+// RUN: -emit-llvm -o - | FileCheck %t/Mod.cppm
+// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple %t/Use.cpp \
+// RUN: -emit-llvm -fprebuilt-module-path=%t -o - | \
+// RUN: FileCheck %t/Use.cpp
+
+//--- Base.cppm
+export module Base;
+
+export template <class>
+class Base
+{
+public:
+ constexpr Base();
+ constexpr virtual ~Base();
+};
+
+template <class X>
+constexpr Base<X>::Base() = default;
+
+template <class X>
+constexpr Base<X>::~Base() = default;
+
+//--- Sub.cppm
+export module Sub;
+export import Base;
+
+export class Sub : public Base<int>
+{
+};
+
+// CHECK: @_ZTIW4Base4BaseIiE = {{.*}}linkonce_odr
+
+//--- main.cpp
+import Sub;
+
+int main()
+{
+ Base<int> *b = new Sub();
+ delete b;
+}
+
+// CHECK: @_ZTIW4Base4BaseIiE = {{.*}}linkonce_odr
+
+//--- Mod.cppm
+export module Mod;
+
+export class NonTemplate {
+public:
+ virtual ~NonTemplate();
+};
+
+// CHECK: @_ZTIW3Mod11NonTemplate = {{.*}}constant
+
+export template <class C>
+class Template {
+public:
+ virtual ~Template();
+};
+
+export template<>
+class Template<char> {
+public:
+ virtual ~Template();
+};
+
+// CHECK: @_ZTIW3Mod8TemplateIcE = {{.*}}constant
+
+export template class Template<unsigned>;
+
+// CHECK: @_ZTIW3Mod8TemplateIjE = {{.*}}weak_odr
+
+export extern template class Template<double>;
+
+auto v = new Template<signed int>();
+
+// CHECK: @_ZTIW3Mod8TemplateIiE = {{.*}}linkonce_odr
+
+//--- Use.cpp
+import Mod;
+
+auto v1 = new NonTemplate();
+auto v2 = new Template<char>();
+auto v3 = new Template<unsigned>();
+auto v4 = new Template<double>();
+auto v5 = new Template<signed int>();
+auto v6 = new Template<NonTemplate>();
+
+// CHECK: @_ZTVW3Mod11NonTemplate = {{.*}}external
+// CHECK: @_ZTVW3Mod8TemplateIcE = {{.*}}external
+// CHECK: @_ZTVW3Mod8TemplateIjE = {{.*}}weak_odr
+// CHECK: @_ZTSW3Mod8TemplateIjE = {{.*}}weak_odr
+// CHECK: @_ZTIW3Mod8TemplateIjE = {{.*}}weak_odr
+// CHECK: @_ZTVW3Mod8TemplateIdE = {{.*}}external
+// CHECK: @_ZTVW3Mod8TemplateIiE = {{.*}}linkonce_odr
+// CHECK: @_ZTSW3Mod8TemplateIiE = {{.*}}linkonce_odr
+// CHECK: @_ZTIW3Mod8TemplateIiE = {{.*}}linkonce_odr
+// CHECK: @_ZTVW3Mod8TemplateIS_11NonTemplateE = {{.*}}linkonce_odr
+// CHECK: @_ZTSW3Mod8TemplateIS_11NonTemplateE = {{.*}}linkonce_odr
+// CHECK: @_ZTIW3Mod8TemplateIS_11NonTemplateE = {{.*}}linkonce_odr
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