`for` loop crashes the kernel

[Vipul-Cariappa]

EDITED:
Any for loop crashes the kernel. Example:

In [1]: for (int i = 0; i < 5; i++) {}

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ORIGINAL ISSUE FILED:

The following code snippet crashes the kernel with 11, 14 & 17 stdc++:

In [1]: #include <iostream>
   ...: #include <string>
   ...: #include <vector>

In [2]: std::vector<std::string> strs;
   ...: strs.push_back("xeus");
   ...: strs.push_back("clang");
   ...: strs.push_back("repl");

In [3]: for (size_t i = 0; i < strs.size(); i++) {
   ...:     std::cout << strs.at(i) << std::endl;
   ...: }

But the following runs fine:

In [1]: #include <iostream>
   ...: #include <string>
   ...: #include <vector>

In [2]: std::vector<std::string> strs;
   ...: strs.push_back("xeus");
   ...: strs.push_back("clang");
   ...: strs.push_back("repl");

In [3]: std::cout << strs.at(0) << std::endl;
   ...: std::cout << strs.at(1) << std::endl;
   ...: std::cout << strs.at(2) << std::endl;

[Vipul-Cariappa]

clang-repl (LLVM 18) also crashes while executing any for loop.

❯ ./clang-repl
clang-repl> for (int i = 0; i < 5; i++) {}
clang-repl: /home/vipul/Workspace/cpp-py/compiler-research/llvm-project/clang/lib/CodeGen/CGDecl.cpp:160: void clang::CodeGen::CodeGenFunction::EmitDecl(const clang::Decl&): Assertion `VD.isLocalVarDecl() && "Should not see file-scope variables inside a function!"' failed.

[vgvassilev]

Please open a bug against upstream llvm. I remember fixing similar problems upstream

[Vipul-Cariappa]

LLVM 19 does not crash with the for loop example I specified above. I am trying to compile xeus-clang-repl with LLVM 19 but cannot. I get the following error:

CMake Error at CMakeLists.txt:105 (message):
  Found unsupported version: LLVM 19.1.2;

  Please set LLVM_DIR pointing to the llvm version 8.0 to 18.1.x build or
  installation folder

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Please open a bug against upstream llvm.

Not required till we test with LLVM 19, I guess.

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EDITED

The for loop bug is fixed with LLVM 19. I got it compiled.

[Vipul-Cariappa]

@vgvassilev I guess we can close this issue. And put a remake saying only LLVM 19 is supported. And update the README.
But then we may not be able to use clad.

[vgvassilev]

I am not sure I understand how this is an issue for clad?

[Vipul-Cariappa]

If we use LLVM 19 and compile xeus-clang-repl, the for loop bug will be fixed. But as clad does not support LLVM 19 yet, we will remove support for clad.