[all-commits] [llvm/llvm-project] 21fb19: [clang-repl] : Fix clang-repl crash with --cuda fl...

[Anutosh Bhat via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 21fb19f3b5d572f608e959af895d781b9b24fbbd
      https://github.com/llvm/llvm-project/commit/21fb19f3b5d572f608e959af895d781b9b24fbbd
  Author: Anutosh Bhat <andersonbhat491 at gmail.com>
  Date:   2025-04-26 (Sat, 26 Apr 2025)

  Changed paths:
    M clang/include/clang/Interpreter/Interpreter.h
    M clang/lib/Interpreter/DeviceOffload.cpp
    M clang/lib/Interpreter/DeviceOffload.h
    M clang/lib/Interpreter/Interpreter.cpp

  Log Message:
  -----------
  [clang-repl] : Fix clang-repl crash with --cuda flag (#136404)

`clang-repl --cuda` was previously crashing with a segmentation fault,
instead of reporting a clean error
```
(base) anutosh491 at Anutoshs-MacBook-Air bin % ./clang-repl --cuda
#0 0x0000000111da4fbc llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/local/libexec/llvm-20/lib/libLLVM.dylib+0x150fbc)
#1 0x0000000111da31dc llvm::sys::RunSignalHandlers() (/opt/local/libexec/llvm-20/lib/libLLVM.dylib+0x14f1dc)
#2 0x0000000111da5628 SignalHandler(int) (/opt/local/libexec/llvm-20/lib/libLLVM.dylib+0x151628)
#3 0x000000019b242de4 (/usr/lib/system/libsystem_platform.dylib+0x180482de4)
#4 0x0000000107f638d0 clang::IncrementalCUDADeviceParser::IncrementalCUDADeviceParser(std::__1::unique_ptr<clang::CompilerInstance, std::__1::default_delete<clang::CompilerInstance>>, clang::CompilerInstance&, llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem>, llvm::Error&, std::__1::list<clang::PartialTranslationUnit, std::__1::allocator<clang::PartialTranslationUnit>> const&) (/opt/local/libexec/llvm-20/lib/libclang-cpp.dylib+0x216b8d0)
#5 0x0000000107f638d0 clang::IncrementalCUDADeviceParser::IncrementalCUDADeviceParser(std::__1::unique_ptr<clang::CompilerInstance, std::__1::default_delete<clang::CompilerInstance>>, clang::CompilerInstance&, llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem>, llvm::Error&, std::__1::list<clang::PartialTranslationUnit, std::__1::allocator<clang::PartialTranslationUnit>> const&) (/opt/local/libexec/llvm-20/lib/libclang-cpp.dylib+0x216b8d0)
#6 0x0000000107f6bac8 clang::Interpreter::createWithCUDA(std::__1::unique_ptr<clang::CompilerInstance, std::__1::default_delete<clang::CompilerInstance>>, std::__1::unique_ptr<clang::CompilerInstance, std::__1::default_delete<clang::CompilerInstance>>) (/opt/local/libexec/llvm-20/lib/libclang-cpp.dylib+0x2173ac8)
#7 0x000000010206f8a8 main (/opt/local/libexec/llvm-20/bin/clang-repl+0x1000038a8)
#8 0x000000019ae8c274 
Segmentation fault: 11
```


The underlying issue was that the `DeviceCompilerInstance` (used for
device-side CUDA compilation) was never initialized with a `Sema`, which
is required before constructing the `IncrementalCUDADeviceParser`.


https://github.com/llvm/llvm-project/blob/89687e6f383b742a3c6542dc673a84d9f82d02de/clang/lib/Interpreter/DeviceOffload.cpp#L32


https://github.com/llvm/llvm-project/blob/89687e6f383b742a3c6542dc673a84d9f82d02de/clang/lib/Interpreter/IncrementalParser.cpp#L31

Unlike the host-side `CompilerInstance` which runs `ExecuteAction`
inside the Interpreter constructor (thereby setting up Sema), the
device-side CI was passed into the parser uninitialized, leading to an
assertion or crash when accessing its internals.

To fix this, I refactored the `Interpreter::create` method to include an
optional `DeviceCI` parameter. If provided, we know we need to take care
of this instance too. Only then do we construct the
`IncrementalCUDADeviceParser`.



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