[llvm-branch-commits] [clang] 863b2e5 - [C++20] [Modules] Fix the duplicated static initializer problem (#114193)
Tobias Hieta via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Mon Nov 18 08:00:17 PST 2024
Author: Chuanqi Xu
Date: 2024-11-15T09:32:03+01:00
New Revision: 863b2e599016ada8b2f4cc4d8c59eb7d8f61ee7f
URL: https://github.com/llvm/llvm-project/commit/863b2e599016ada8b2f4cc4d8c59eb7d8f61ee7f
DIFF: https://github.com/llvm/llvm-project/commit/863b2e599016ada8b2f4cc4d8c59eb7d8f61ee7f.diff
LOG: [C++20] [Modules] Fix the duplicated static initializer problem (#114193)
Reproducer:
```
//--- a.cppm
export module a;
int func();
static int a = func();
//--- a.cpp
import a;
```
The `func()` should only execute once. However, before this patch we
will somehow import `static int a` from a.cppm incorrectly and
initialize that again.
This is super bad and can introduce serious runtime behaviors.
And also surprisingly, it looks like the root cause of the problem is
simply some oversight choosing APIs.
(cherry picked from commit 259eaa6878ead1e2e7ef572a874dc3d885c1899b)
Added:
clang/test/Modules/static-initializer.cppm
Modified:
clang/lib/CodeGen/CodeGenModule.cpp
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 151505baf38db1..2a5d5f9083ae65 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -7080,8 +7080,8 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
// For C++ standard modules we are done - we will call the module
// initializer for imported modules, and that will likewise call those for
// any imports it has.
- if (CXX20ModuleInits && Import->getImportedOwningModule() &&
- !Import->getImportedOwningModule()->isModuleMapModule())
+ if (CXX20ModuleInits && Import->getImportedModule() &&
+ Import->getImportedModule()->isNamedModule())
break;
// For clang C++ module map modules the initializers for sub-modules are
diff --git a/clang/test/Modules/static-initializer.cppm b/clang/test/Modules/static-initializer.cppm
new file mode 100644
index 00000000000000..10d4854ee67fa6
--- /dev/null
+++ b/clang/test/Modules/static-initializer.cppm
@@ -0,0 +1,18 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: split-file %s %t
+//
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 %t/a.cppm -emit-module-interface -o %t/a.pcm
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 %t/a.cpp -fmodule-file=a=%t/a.pcm -emit-llvm -o - | FileCheck %t/a.cpp
+
+//--- a.cppm
+export module a;
+int func();
+static int a = func();
+
+//--- a.cpp
+import a;
+
+// CHECK-NOT: internal global
+// CHECK-NOT: __cxx_global_var_init
+
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