[clang] [C++20] [Moduels] Correct the linkage of const variable in language linkage from module interfaces (PR #102574)
Chuanqi Xu via cfe-commits
cfe-commits at lists.llvm.org
Thu Aug 8 23:16:41 PDT 2024
https://github.com/ChuanqiXu9 created https://github.com/llvm/llvm-project/pull/102574
Close https://github.com/llvm/llvm-project/issues/99825
The root cause of the issue is that I didn't realize the things in implicit global module (the language linkage in module interfaces) should be considered in module purview.
>From cb862a139cc2a3e987b37092a9a03bb05fa060ea Mon Sep 17 00:00:00 2001
From: Chuanqi Xu <yedeng.yd at linux.alibaba.com>
Date: Fri, 9 Aug 2024 14:14:08 +0800
Subject: [PATCH] [C++20] [Moduels] Correct the linkage of const variable in
language linkage from module interfaces
---
clang/lib/AST/Decl.cpp | 14 +++++++-------
clang/test/Modules/pr99825.cppm | 8 ++++++++
2 files changed, 15 insertions(+), 7 deletions(-)
create mode 100644 clang/test/Modules/pr99825.cppm
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index d832ce4190ff1a..e125143bc1b270 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -583,12 +583,6 @@ static bool isSingleLineLanguageLinkage(const Decl &D) {
return false;
}
-static bool isDeclaredInModuleInterfaceOrPartition(const NamedDecl *D) {
- if (auto *M = D->getOwningModule())
- return M->isInterfaceOrPartition();
- return false;
-}
-
static LinkageInfo getExternalLinkageFor(const NamedDecl *D) {
return LinkageInfo::external();
}
@@ -642,7 +636,13 @@ LinkageComputer::getLVForNamespaceScopeDecl(const NamedDecl *D,
// (There is no equivalent in C99.)
if (Context.getLangOpts().CPlusPlus && Var->getType().isConstQualified() &&
!Var->getType().isVolatileQualified() && !Var->isInline() &&
- !isDeclaredInModuleInterfaceOrPartition(Var) &&
+ ![Var]() {
+ // Check if it is module purview except private module fragment
+ // and implementation unit.
+ if (auto *M = Var->getOwningModule())
+ return M->isInterfaceOrPartition() || M->isImplicitGlobalModule();
+ return false;
+ }() &&
!isa<VarTemplateSpecializationDecl>(Var) &&
!Var->getDescribedVarTemplate()) {
const VarDecl *PrevVar = Var->getPreviousDecl();
diff --git a/clang/test/Modules/pr99825.cppm b/clang/test/Modules/pr99825.cppm
new file mode 100644
index 00000000000000..fe6541c6e68e50
--- /dev/null
+++ b/clang/test/Modules/pr99825.cppm
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -std=c++20 %s -fsyntax-only -verify
+// expected-no-diagnostics
+export module mod;
+
+extern "C++"
+{
+ export constexpr auto x = 10;
+}
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