After #146018 was landed, we start seeing rustc panics on Windows when we build rustc from source. As the compiler failed to locate the `rc.exe` The rust revision we test on is eec6bd9d69832f57341c6de6a93fa7b9f47e2111 . We did a small instrumentation for debugging purpose: ``` diff --git a/compiler/rustc_windows_rc/src/lib.rs b/compiler/rustc_windows_rc/src/lib.rs index caa5e5ef276..ea3759dd3ae 100644 --- a/compiler/rustc_windows_rc/src/lib.rs +++ b/compiler/rustc_windows_rc/src/lib.rs @@ -145,6 +145,7 @@ fn find_windows_sdk_tool(arch_or_target: &str, tool_name: &str) -> Option<path:: // cc does include the Windows SDK tools in the PATH environment of MSVC tools. let msvc_linker = windows_registry::find_tool(arch_or_target, "link.exe")?; + eprintln!("tool: {:?}", msvc_linker); let path = &msvc_linker.env().iter().find(|(k, _)| k == "PATH")?.1; find_tool_in_path(tool_name, path) } ``` Steps we run: * Assume VS2022 Community or VS2022 build tools is installed. * Assume a recent clang-cl is available. Either built from source or from LLVM release. In our case, we built from source and it is located in `C:/src/llvm-prebuilt/clang/windows-amd64` * Checkout rust with submodules to `C:\src\rust` , to revision `eec6bd9d69832f57341c6de6a93fa7b9f47e2111` which includes the PR #146018 . * Start `x64 Native Tools Command Prompt for VS 2022` terminal from the start menu * Navigate to C:\src\rust. create `config.toml` * Start the build with `python x.py install -v` Failure message with RUST_BACKTRACE=1 ``` Compiling rustc_span v0.0.0 (C:\src\rust\compiler\rustc_span) error: failed to run custom build command for `rustc_driver v0.0.0 (C:\src\rust\compiler\rustc_driver)` note: To improve backtraces for build dependencies, set the CARGO_PROFILE_RELEASE_BUILD_OVERRIDE_DEBUG=true environment variable to enable debug information generation. Caused by: process didn't exit successfully: `C:\src\rust\fuchsia-build\x86_64-pc-windows-msvc\stage1-rustc\release\build\rustc_driver-388d58225b8919fc\build-script-build` (exit code: 101) --- stderr tool: Tool { path: "C:\\Program Files (x86)\\Microsoft Visual Studio\\2022\\BuildTools\\VC\\Tools\\MSVC\\14.38.33130\\bin\\HostX64\\x64\\link.exe", cc_wrapper_path: None, cc_wrapper_args: [], args: [], env: [], family: Msvc { clang_cl: false }, cuda: false, removed_args: [], has_internal_target_arg: false } thread 'main' panicked at compiler\rustc_windows_rc\src\lib.rs:39:77: found rc.exe stack backtrace: 0: std::panicking::begin_panic_handler at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\panicking.rs:697 1: core::panicking::panic_fmt at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\core\src\panicking.rs:75 2: core::panicking::panic_display at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\core\src\panicking.rs:268 3: core::option::expect_failed at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\core\src\option.rs:2139 4: core::option::Option<T>::expect 5: rustc_windows_rc::compile_windows_resource_file 6: build_script_build::main 7: build_script_build::main 8: std::rt::lang_start 9: std::rt::lang_start 10: std::rt::lang_start 11: std::rt::lang_start_internal::closure$0 at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\rt.rs:175 12: std::panicking::catch_unwind::do_call at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\panicking.rs:589 13: std::panicking::catch_unwind at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\panicking.rs:552 14: std::panic::catch_unwind at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\panic.rs:359 15: std::rt::lang_start_internal at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\rt.rs:171 16: std::rt::lang_start 17: main 18: invoke_main at D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:78 19: __scrt_common_main_seh at D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288 20: BaseThreadInitThunk 21: RtlUserThreadStart note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace. warning: build failed, waiting for other jobs to finish... error: failed to run custom build command for `rustc-main v0.0.0 (C:\src\rust\compiler\rustc)` note: To improve backtraces for build dependencies, set the CARGO_PROFILE_RELEASE_BUILD_OVERRIDE_DEBUG=true environment variable to enable debug information generation. Caused by: process didn't exit successfully: `C:\src\rust\fuchsia-build\x86_64-pc-windows-msvc\stage1-rustc\release\build\rustc-main-12e8bac0d7cbd909\build-script-build` (exit code: 101) --- stderr tool: Tool { path: "C:\\Program Files (x86)\\Microsoft Visual Studio\\2022\\BuildTools\\VC\\Tools\\MSVC\\14.38.33130\\bin\\HostX64\\x64\\link.exe", cc_wrapper_path: None, cc_wrapper_args: [], args: [], env: [], family: Msvc { clang_cl: false }, cuda: false, removed_args: [], has_internal_target_arg: false } thread 'main' panicked at compiler\rustc_windows_rc\src\lib.rs:39:77: found rc.exe stack backtrace: 0: std::panicking::begin_panic_handler at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\panicking.rs:697 1: core::panicking::panic_fmt at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\core\src\panicking.rs:75 2: core::panicking::panic_display at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\core\src\panicking.rs:268 3: core::option::expect_failed at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\core\src\option.rs:2139 4: core::option::Option<T>::expect 5: rustc_windows_rc::compile_windows_resource_file 6: build_script_build::main 7: build_script_build::main 8: build_script_build::main 9: std::rt::lang_start 10: std::rt::lang_start 11: std::rt::lang_start 12: std::rt::lang_start_internal::closure$0 at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\rt.rs:175 13: std::panicking::catch_unwind::do_call at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\panicking.rs:589 14: std::panicking::catch_unwind at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\panicking.rs:552 15: std::panic::catch_unwind at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\panic.rs:359 16: std::rt::lang_start_internal at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library\std\src\rt.rs:171 17: std::rt::lang_start 18: main 19: invoke_main at D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:78 20: __scrt_common_main_seh at D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288 21: BaseThreadInitThunk 22: RtlUserThreadStart note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace. command did not execute successfully: "C:\\src\\rust\\fuchsia-build\\x86_64-pc-windows-msvc\\stage0\\bin\\cargo.exe" "build" "--target" "x86_64-pc-windows-msvc" "-Zbinary-dep-depinfo" "-j" "64" "-Zroot-dir=C:\\src\\rust" "--release" "--features" "llvm max_level_info" "--manifest-path" "C:\\src\\rust\\compiler/rustc/Cargo.toml" "--message-format" "json-render-diagnostics" (failure_mode=Exit) expected success, got: exit code: 101 Traceback (most recent call last): File "C:\src\rust\x.py", line 53, in <module> bootstrap.main() File "C:\src\rust\src\bootstrap\bootstrap.py", line 1393, in main bootstrap(args) File "C:\src\rust\src\bootstrap\bootstrap.py", line 1368, in bootstrap run(args, env=env, verbose=build.verbose, is_bootstrap=True) File "C:\src\rust\src\bootstrap\bootstrap.py", line 237, in run raise RuntimeError(err) RuntimeError: failed to run: C:\src\rust\fuchsia-build\bootstrap\debug\bootstrap.exe install -v ``` As you can see the rc.exe failed to be found (with a unclear "found rc.exe" message in stderr) and caused a panic. The `msvc_linker` object has an empty `env` map, which is why it eventually the following step to find rc.exe from env['PATH'] failed and triggered the panic. The bug is probably in `find_msvc_environment` function in https://github.com/rust-lang/cc-rs/blob/ac2192ced40bc82d69dd500bd561aa65c186610e/find-msvc-tools/src/find_tools.rs#L464 as it returned a tool object with empty env map. The config.toml we used is ``` change-id = 146435 [llvm] download-ci-llvm = true #optimize = true #thin-lto = false #ninja = true #targets = "X86" #build-config = { CMAKE_SYSROOT="C:/src/winsdk" } #use-libcxx = true # TODO(https://github.com/rust-lang/rust/issues/94983) # We shouldn't have to set this to false to enable statically linking libc++ #static-libstdcpp = false [build] ccache = false target = ["x86_64-pc-windows-msvc"] build = "x86_64-pc-windows-msvc" build-dir = "fuchsia-build" submodules = false docs = false extended = true cargo-native-static = true tools = ["cargo", "rustfmt", "cargo-fmt", "clippy", "src", "llvm-tools", "rustdoc", "rust-analyzer-proc-macro-srv"] [install] prefix = "C:/src/rust/install_prefix" sysconfdir = "etc" [rust] download-rustc = false optimize = true codegen-units = 1 codegen-units-std = 1 channel = "nightly" lld = false llvm-libunwind = "in-tree" jemalloc = false verbose-tests = true # Enable full debuginfo for libstd. debuginfo-level-std = 2 [dist] [target.x86_64-pc-windows-msvc] cc = "C:/src/llvm-prebuilt/clang/windows-amd64/bin/clang-cl.exe" cxx = "C:/src/llvm-prebuilt/clang/windows-amd64/bin/clang-cl.exe" ar = "C:/src/llvm-prebuilt/clang/windows-amd64/bin/llvm-lib.exe" ranlib = "C:/src/llvm-prebuilt/clang/windows-amd64/bin/llvm-ranlib.exe" linker = "C:/src/llvm-prebuilt/clang/windows-amd64/bin/lld-link.exe" profiler = true llvm-has-rust-patches = true ```
