[C++20] [Modules] Fix the duplicated static initializer problem #114193
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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.
ChuanqiXu9
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clang:modules
llvmbot
added
clang
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@llvm/pr-subscribers-clang-codegen @llvm/pr-subscribers-clang-modules Author: Chuanqi Xu (ChuanqiXu9) ChangesReproducer: The 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. Full diff: https://github.com/llvm/llvm-project/pull/114193.diff 2 Files Affected:
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 2bcca5e85bdfeb..ba376f9ecfacde 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -7146,8 +7146,8 @@ 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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Given the problem is very serious and the solution is pretty simple, I'd like to backport this to 19.x. |
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/cherry-pick 259eaa6 |
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/pull-request #114197 |
NoumanAmir657
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Nov 4, 2024
…#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.
tru
pushed a commit
to llvmbot/llvm-project
that referenced
this pull request
Nov 15, 2024
…#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 259eaa6)
nikic
pushed a commit
to rust-lang/llvm-project
that referenced
this pull request
Nov 20, 2024
…#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 259eaa6)
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Reproducer:
The
func()should only execute once. However, before this patch we will somehow importstatic int afrom 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.