$PWD ends up in IDxcIncludeHandler::LoadSource when compiling DXIL on Linux

[MarijnS95]

While compiling DXIL on Linux through the COM API (of libdxcompiler.so) we get strange IDxcIncludeHandler callbacks with the current working directory as file path - which is definitely not a header file to be included. It seems to be happening while retrieving information about the current working directory, following the stacktrace below:

..
load_source (.cargo/registry/src/github.com-1ecc6299db9ec823/hassle-rs-0.7.0/src/wrapper.rs:187)
dxcutil::DxcArgsFileSystemImpl::TryFindOrOpen(wchar_t const*, unsigned long&) (@dxcutil::DxcArgsFileSystemImpl::TryFindOrOpen(wchar_t const*, unsigned long&):45)
dxcutil::DxcArgsFileSystemImpl::GetFileAttributesW(wchar_t const*) (@dxcutil::DxcArgsFileSystemImpl::GetFileAttributesW(wchar_t const*):74)
dxcutil::DxcArgsFileSystemImpl::Stat(char const*, stat*) (@dxcutil::DxcArgsFileSystemImpl::Stat(char const*, stat*):48)
llvm::sys::fs::status(llvm::Twine const&, llvm::sys::fs::file_status&) (@llvm::sys::fs::status(llvm::Twine const&, llvm::sys::fs::file_status&):24)
llvm::sys::fs::current_path(llvm::SmallVectorImpl<char>&) (@llvm::sys::fs::current_path(llvm::SmallVectorImpl<char>&):48)
clang::CodeGen::CGDebugInfo::getCurrentDirname() (@clang::CodeGen::CGDebugInfo::getCurrentDirname():29)
clang::CodeGen::CGDebugInfo::CreateCompileUnit() (@clang::CodeGen::CGDebugInfo::CreateCompileUnit():125)
clang::CodeGen::CGDebugInfo::CGDebugInfo(clang::CodeGen::CodeGenModule&) (@clang::CodeGen::CGDebugInfo::CGDebugInfo(clang::CodeGen::CodeGenModule&):87)
clang::CodeGen::CodeGenModule::CodeGenModule(clang::ASTContext&, clang::HeaderSearchOptions const&, clang::PreprocessorOptions const&, clang::CodeGenOptions const&, llvm::Module&, llvm::DataLayout const&, clang::DiagnosticsEngine&, clang::CoverageSourceInfo*) (@clang::CodeGen::CodeGenModule::CodeGenModule(clang::ASTContext&, clang::HeaderSearchOptions const&, clang::PreprocessorOptions const&, clang::CodeGenOptions const&, llvm::Module&, llvm::DataLayout const&, clang::DiagnosticsEngine&, clang::CoverageSourceInfo*):305)
(anonymous namespace)::CodeGeneratorImpl::Initialize(clang::ASTContext&) (@(anonymous namespace)::CodeGeneratorImpl::Initialize(clang::ASTContext&):60)
clang::BackendConsumer::Initialize(clang::ASTContext&) (@clang::BackendConsumer::Initialize(clang::ASTContext&):24)
clang::Sema::Initialize() (@clang::Sema::Initialize():13)
clang::Parser::Initialize() (@clang::Parser::Initialize():66)
clang::ParseAST(clang::Sema&, bool, bool) (@clang::ParseAST(clang::Sema&, bool, bool):56)
clang::FrontendAction::Execute() (@clang::FrontendAction::Execute():22)
DxcCompiler::Compile(DxcBuffer const*, wchar_t const**, unsigned int, IDxcIncludeHandler*, _GUID const&, void**) (@DxcCompiler::Compile(DxcBuffer const*, wchar_t const**, unsigned int, IDxcIncludeHandler*, _GUID const&, void**):2882)
hlsl::DxcCompilerAdapter::WrapCompile(bool, IDxcBlob*, wchar_t const*, wchar_t const*, wchar_t const*, wchar_t const**, unsigned int, DxcDefine const*, unsigned int, IDxcIncludeHandler*, IDxcOperationResult**, wchar_t**, IDxcBlob**) (@hlsl::DxcCompilerAdapter::WrapCompile(bool, IDxcBlob*, wchar_t const*, wchar_t const*, wchar_t const*, wchar_t const**, unsigned int, DxcDefine const*, unsigned int, IDxcIncludeHandler*, IDxcOperationResult**, wchar_t**, IDxcBlob**):288)

Related: Traverse-Research/hassle-rs#27