run-make: audit the ignore-{windows,msvc,windows-msvc} tests
#128602
Labels
A-run-make
Area: port run-make Makefiles to rmake.rs
A-testsuite
Area: The testsuite used to check the correctness of rustc
C-bug
Category: This is a bug.
O-windows
Operating system: Windows
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
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jieyouxu
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A-testsuite
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rustbot
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needs-triage
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If the Windows experts could take a look when they have time, it would be very helpful :3 |
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Hey Windows Group! This bug has been identified as a good "Windows candidate". cc @albertlarsan68 @arlosi @ChrisDenton @danielframpton @gdr-at-ms @kennykerr @luqmana @lzybkr @nico-abram @retep998 @sivadeilra @wesleywiser |
jieyouxu
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needs-triage
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You can find the current run-make tests that have I'm happy to help answer questions about the rmake.rs setup :3 |
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I very quickly did one in #128603. It uses a library function rather than |
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I don't have time to fix it atm but zero-extend-abi-param-passing looks like another easy one. It just needs two things. A version of
Or the |
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Ok I've done the above now as well as the other non-Makefile tests. I've not looked at the Makefile tests yet since I'd prefer to wait until they've been ported to pure Rust as I find it much easier to work on Rust tests without the added layer of emulation. |
jieyouxu
changed the title
ignore-msvc testsignore-{windows,msvc,windows-msvc} tests
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Somewhat related, do you have an idea how to make test run on windows-gnullvm and msvc only? Then gnullvm will be also excluded. There are few things (like CFGuad) that will probsbly never work with mingw-w64+GNU targets but are supported on mingw-w64+LLVM (not yet within Rust). |
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@mati865 I think this is a problem with how the windows-gnu matcher in compiletest works, do you mind filing a new issue (i.e. windows-gnu also means ignore gnullvm and there's no way to specifiy running windows-gnu but skipping gnu-llvm)? |
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Sure, I'll do it later today. |
GuillaumeGomez
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Jun 7, 2025
Change __rust_no_alloc_shim_is_unstable to be a function This fixes a long sequence of issues: 1. A customer reported that building for Arm64EC was broken: rust-lang#138541 2. This was caused by a bug in my original implementation of Arm64EC support, namely that only functions on Arm64EC need to be decorated with `#` but Rust was decorating statics as well. 3. Once I corrected Rust to only decorate functions, I started linking failures where the linker couldn't find statics exported by dylib dependencies. This was caused by the compiler not marking exported statics in the generated DEF file with `DATA`, thus they were being exported as functions not data. 4. Once I corrected the way that the DEF files were being emitted, the linker started failing saying that it couldn't find `__rust_no_alloc_shim_is_unstable`. This is because the MSVC linker requires the declarations of statics imported from other dylibs to be marked with `dllimport` (whereas it will happily link to functions imported from other dylibs whether they are marked `dllimport` or not). 5. I then made a change to ensure that `__rust_no_alloc_shim_is_unstable` was marked as `dllimport`, but the MSVC linker started emitting warnings that `__rust_no_alloc_shim_is_unstable` was marked as `dllimport` but was declared in an obj file. This is a harmless warning which is a performance hint: anything that's marked `dllimport` must be indirected via an `__imp` symbol so I added a linker arg in the target to suppress the warning. 6. A customer then reported a similar warning when using `lld-link` (<rust-lang#140176 (comment)>). I don't think it was an implementation difference between the two linkers but rather that, depending on the obj that the declaration versus uses of `__rust_no_alloc_shim_is_unstable` landed in we would get different warnings, so I suppressed that warning as well: rust-lang#140954. 7. Another customer reported that they weren't using the Rust compiler to invoke the linker, thus these warnings were breaking their build: <rust-lang#140176 (comment)>. At that point, my original change was reverted (rust-lang#141024) leaving Arm64EC broken yet again. Taking a step back, a lot of these linker issues arise from the fact that `__rust_no_alloc_shim_is_unstable` is marked as `extern "Rust"` in the standard library and, therefore, assumed to be a foreign item from a different crate BUT the Rust compiler may choose to generate it either in the current crate, some other crate that will be statically linked in OR some other crate that will by dynamically imported. Worse yet, it is impossible while building a given crate to know if `__rust_no_alloc_shim_is_unstable` will statically linked or dynamically imported: it might be that one of its dependent crates is the one with an allocator kind set and thus that crate (which is compiled later) will decide depending if it has any dylib dependencies or not to import `__rust_no_alloc_shim_is_unstable` or generate it. Thus, there is no way to know if the declaration of `__rust_no_alloc_shim_is_unstable` should be marked with `dllimport` or not. There is a simple fix for all this: there is no reason `__rust_no_alloc_shim_is_unstable` must be a static. It needs to be some symbol that must be linked in; thus, it could easily be a function instead. As a function, there is no need to mark it as `dllimport` when dynamically imported which avoids the entire mess above. There may be a perf hit for changing the `volatile load` to be a `tail call`, so I'm happy to change that part back (although I question what the codegen of a `volatile load` would look like, and if the backend is going to try to use load-acquire semantics). Build with this change applied BEFORE rust-lang#140176 was reverted to demonstrate that there are no linking issues with either MSVC or MinGW: <https://github.com/rust-lang/rust/actions/runs/15078657205> Incidentally, I fixed `tests/run-make/no-alloc-shim` to work with MSVC as I needed it to be able to test locally (FYI for rust-lang#128602) r? `@bjorn3` cc `@jieyouxu`
workingjubilee
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Jun 10, 2025
Change __rust_no_alloc_shim_is_unstable to be a function This fixes a long sequence of issues: 1. A customer reported that building for Arm64EC was broken: rust-lang#138541 2. This was caused by a bug in my original implementation of Arm64EC support, namely that only functions on Arm64EC need to be decorated with `#` but Rust was decorating statics as well. 3. Once I corrected Rust to only decorate functions, I started linking failures where the linker couldn't find statics exported by dylib dependencies. This was caused by the compiler not marking exported statics in the generated DEF file with `DATA`, thus they were being exported as functions not data. 4. Once I corrected the way that the DEF files were being emitted, the linker started failing saying that it couldn't find `__rust_no_alloc_shim_is_unstable`. This is because the MSVC linker requires the declarations of statics imported from other dylibs to be marked with `dllimport` (whereas it will happily link to functions imported from other dylibs whether they are marked `dllimport` or not). 5. I then made a change to ensure that `__rust_no_alloc_shim_is_unstable` was marked as `dllimport`, but the MSVC linker started emitting warnings that `__rust_no_alloc_shim_is_unstable` was marked as `dllimport` but was declared in an obj file. This is a harmless warning which is a performance hint: anything that's marked `dllimport` must be indirected via an `__imp` symbol so I added a linker arg in the target to suppress the warning. 6. A customer then reported a similar warning when using `lld-link` (<rust-lang#140176 (comment)>). I don't think it was an implementation difference between the two linkers but rather that, depending on the obj that the declaration versus uses of `__rust_no_alloc_shim_is_unstable` landed in we would get different warnings, so I suppressed that warning as well: rust-lang#140954. 7. Another customer reported that they weren't using the Rust compiler to invoke the linker, thus these warnings were breaking their build: <rust-lang#140176 (comment)>. At that point, my original change was reverted (rust-lang#141024) leaving Arm64EC broken yet again. Taking a step back, a lot of these linker issues arise from the fact that `__rust_no_alloc_shim_is_unstable` is marked as `extern "Rust"` in the standard library and, therefore, assumed to be a foreign item from a different crate BUT the Rust compiler may choose to generate it either in the current crate, some other crate that will be statically linked in OR some other crate that will by dynamically imported. Worse yet, it is impossible while building a given crate to know if `__rust_no_alloc_shim_is_unstable` will statically linked or dynamically imported: it might be that one of its dependent crates is the one with an allocator kind set and thus that crate (which is compiled later) will decide depending if it has any dylib dependencies or not to import `__rust_no_alloc_shim_is_unstable` or generate it. Thus, there is no way to know if the declaration of `__rust_no_alloc_shim_is_unstable` should be marked with `dllimport` or not. There is a simple fix for all this: there is no reason `__rust_no_alloc_shim_is_unstable` must be a static. It needs to be some symbol that must be linked in; thus, it could easily be a function instead. As a function, there is no need to mark it as `dllimport` when dynamically imported which avoids the entire mess above. There may be a perf hit for changing the `volatile load` to be a `tail call`, so I'm happy to change that part back (although I question what the codegen of a `volatile load` would look like, and if the backend is going to try to use load-acquire semantics). Build with this change applied BEFORE rust-lang#140176 was reverted to demonstrate that there are no linking issues with either MSVC or MinGW: <https://github.com/rust-lang/rust/actions/runs/15078657205> Incidentally, I fixed `tests/run-make/no-alloc-shim` to work with MSVC as I needed it to be able to test locally (FYI for rust-lang#128602) r? `@bjorn3` cc `@jieyouxu`
workingjubilee
added a commit
to workingjubilee/rustc
that referenced
this issue
Jun 10, 2025
Change __rust_no_alloc_shim_is_unstable to be a function This fixes a long sequence of issues: 1. A customer reported that building for Arm64EC was broken: rust-lang#138541 2. This was caused by a bug in my original implementation of Arm64EC support, namely that only functions on Arm64EC need to be decorated with `#` but Rust was decorating statics as well. 3. Once I corrected Rust to only decorate functions, I started linking failures where the linker couldn't find statics exported by dylib dependencies. This was caused by the compiler not marking exported statics in the generated DEF file with `DATA`, thus they were being exported as functions not data. 4. Once I corrected the way that the DEF files were being emitted, the linker started failing saying that it couldn't find `__rust_no_alloc_shim_is_unstable`. This is because the MSVC linker requires the declarations of statics imported from other dylibs to be marked with `dllimport` (whereas it will happily link to functions imported from other dylibs whether they are marked `dllimport` or not). 5. I then made a change to ensure that `__rust_no_alloc_shim_is_unstable` was marked as `dllimport`, but the MSVC linker started emitting warnings that `__rust_no_alloc_shim_is_unstable` was marked as `dllimport` but was declared in an obj file. This is a harmless warning which is a performance hint: anything that's marked `dllimport` must be indirected via an `__imp` symbol so I added a linker arg in the target to suppress the warning. 6. A customer then reported a similar warning when using `lld-link` (<rust-lang#140176 (comment)>). I don't think it was an implementation difference between the two linkers but rather that, depending on the obj that the declaration versus uses of `__rust_no_alloc_shim_is_unstable` landed in we would get different warnings, so I suppressed that warning as well: rust-lang#140954. 7. Another customer reported that they weren't using the Rust compiler to invoke the linker, thus these warnings were breaking their build: <rust-lang#140176 (comment)>. At that point, my original change was reverted (rust-lang#141024) leaving Arm64EC broken yet again. Taking a step back, a lot of these linker issues arise from the fact that `__rust_no_alloc_shim_is_unstable` is marked as `extern "Rust"` in the standard library and, therefore, assumed to be a foreign item from a different crate BUT the Rust compiler may choose to generate it either in the current crate, some other crate that will be statically linked in OR some other crate that will by dynamically imported. Worse yet, it is impossible while building a given crate to know if `__rust_no_alloc_shim_is_unstable` will statically linked or dynamically imported: it might be that one of its dependent crates is the one with an allocator kind set and thus that crate (which is compiled later) will decide depending if it has any dylib dependencies or not to import `__rust_no_alloc_shim_is_unstable` or generate it. Thus, there is no way to know if the declaration of `__rust_no_alloc_shim_is_unstable` should be marked with `dllimport` or not. There is a simple fix for all this: there is no reason `__rust_no_alloc_shim_is_unstable` must be a static. It needs to be some symbol that must be linked in; thus, it could easily be a function instead. As a function, there is no need to mark it as `dllimport` when dynamically imported which avoids the entire mess above. There may be a perf hit for changing the `volatile load` to be a `tail call`, so I'm happy to change that part back (although I question what the codegen of a `volatile load` would look like, and if the backend is going to try to use load-acquire semantics). Build with this change applied BEFORE rust-lang#140176 was reverted to demonstrate that there are no linking issues with either MSVC or MinGW: <https://github.com/rust-lang/rust/actions/runs/15078657205> Incidentally, I fixed `tests/run-make/no-alloc-shim` to work with MSVC as I needed it to be able to test locally (FYI for rust-lang#128602) r? ``@bjorn3`` cc ``@jieyouxu``
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There are several
ignore-msvc/ignore-windows/ignore-windows-msvcMakefile and rmake.rs (tests that are ported to pure Rust files) run-make tests that have thoseignore-*s because of several common challenges:It would be great and super helpful if Windows experts could take a look at them, and see if some of the
ignore-*s can be resolved or otherwise how we can expand the tests to cover msvc as well, or have proper reasons why they must beignore-*'d. The test suite is quite tricky to run on Windows, see https://rustc-dev-guide.rust-lang.org/tests/running.html?highlight=run-make#windows, seems to require msys2 + make, binutils, diffutils for the remaining Makefiles.ignore-msvc:any_symbol_contains#128603)no-duplicate-libsandzero-extend-abi-param-passing#128649)link-dedup#128638)no-duplicate-libsandzero-extend-abi-param-passing#128649)ignore-windows-msvc:objectinrun-make/symbols-visibility#128607)ignore-windows:needs-symlink, unsure about reproducible paths)no_stdtest) (run-make: explaing why fmt-write-bloat is ignore-windows #128807)The text was updated successfully, but these errors were encountered: