Double-free of exported global string on program exit

[mordante]

The following code is a reduction of a c++20 module application that crashes.
The easiest way to reproduce the crash is by using ASAN.
When the application terminates, it gives a double-free error.

data.cppm

module;
#include <string>                                                               
export module data;
export std::string global;

main.cpp

import data;
int main() { global = "A long string that does not fit in the SSO buffer"; }

[llvmbot]

@llvm/issue-subscribers-clang-modules

[ChuanqiXu9]

Currently, when we use global variables from modules, clang will call the corresponding constructor/destructor for these global variables in the importee. This should be wrong clearly.

As a workaround (if you need), you can add inline keywords in the declaration for the global variable.

[ChuanqiXu9]

Sent https://reviews.llvm.org/D140867

[llvmbot]

@llvm/issue-subscribers-clang-codegen