Controlling Test Execution: Ignore, Only, and Target-Specific Directives

where the test binary's stdout and stderr gets concatenated and then `error-pattern`s are matched on this combined output, which is ??? slightly questionable to say the least. ### Controlling when tests are run These directives are used to ignore the test in some situations, which means the test won't be compiled or run. * `ignore-X` where `X` is a target detail or other criteria on which to ignore the test (see below) * `only-X` is like `ignore-X`, but will *only* run the test on that target or stage * `ignore-auxiliary` is intended for files that *participate* in one or more other main test files but that `compiletest` should not try to build the file itself. Please backlink to which main test is actually using the auxiliary file. * `ignore-test` always ignores the test. This can be used to temporarily disable a test if it is currently not working, but you want to keep it in tree to re-enable it later. Some examples of `X` in `ignore-X` or `only-X`: - A full target triple: `aarch64-apple-ios` - Architecture: `aarch64`, `arm`, `mips`, `wasm32`, `x86_64`, `x86`, ... - OS: `android`, `emscripten`, `freebsd`, `ios`, `linux`, `macos`, `windows`, ... - Environment (fourth word of the target triple): `gnu`, `msvc`, `musl` - WASM: `wasm32-bare` matches `wasm32-unknown-unknown`. `emscripten` also matches that target as well as the emscripten targets. - Pointer width: `32bit`, `64bit` - Endianness: `endian-big` - Stage: `stage1`, `stage2` - Binary format: `elf` - Channel: `stable`, `beta` - When cross compiling: `cross-compile` - When [remote testing] is used: `remote` - When particular debuggers are being tested: `cdb`, `gdb`, `lldb` - When particular debugger versions are matched: `ignore-gdb-version` `compare-mode-split-dwarf`, `compare-mode-split-dwarf-single` - The two different test modes used by coverage tests: `ignore-coverage-map`, `ignore-coverage-run` - When testing a dist toolchain: `dist` - This needs to be enabled with `COMPILETEST_ENABLE_DIST_TESTS=1` - The `rustc_abi` of the target: e.g. `rustc_abi-x86_64-sse2` The following directives will check rustc build settings and target settings: - `needs-asm-support` — ignores if it is running on a target that doesn't have stable support for `asm!` - `needs-profiler-runtime` — ignores the test if the profiler runtime was not enabled for the target (`build.profiler = true` in rustc's `bootstrap.toml`) - `needs-sanitizer-support` — ignores if the sanitizer support was not enabled for the target (`sanitizers = true` in rustc's `bootstrap.toml`) - `needs-sanitizer-{address,hwaddress,leak,memory,thread}` — ignores if the corresponding sanitizer is not enabled for the target (AddressSanitizer, hardware-assisted AddressSanitizer, LeakSanitizer, MemorySanitizer or ThreadSanitizer respectively) - `needs-run-enabled` — ignores if it is a test that gets executed, and running has been disabled. Running tests can be disabled with the `x test --run=never` flag, or running on fuchsia. - `needs-unwind` — ignores if the target does not support unwinding - `needs-rust-lld` — ignores if the rust lld support is not enabled (`rust.lld = true` in `bootstrap.toml`) - `needs-threads` — ignores if the target does not have threading support - `needs-subprocess` — ignores if the target does not have subprocess support - `needs-symlink` — ignores if the target does not support symlinks. This can be the case on Windows if the developer did not enable privileged symlink permissions. - `ignore-std-debug-assertions` — ignores if std was built with debug assertions. - `needs-std-debug-assertions` — ignores if std was not built with debug assertions. - `ignore-rustc-debug-assertions` — ignores if rustc was built with debug assertions. - `needs-rustc-debug-assertions` — ignores if rustc was not built with debug assertions. - `needs-target-has-atomic` — ignores if target does not have support for all specified atomic widths, e.g. the test with `//@ needs-target-has-atomic: 8,

This section details directives that control when tests are executed, including `ignore-X` and `only-X` for target-specific exclusions or inclusions, `ignore-auxiliary` for excluding auxiliary files from direct compilation, and `ignore-test` for temporarily disabling tests. It lists examples of `X` such as target triples, architectures, operating systems, environments, WASM targets, pointer widths, endianness, stages, binary formats, channels, cross-compilation, remote testing, debuggers, coverage test modes, dist toolchains and rustc ABIs. The section also covers directives that check rustc build settings and target settings like `needs-asm-support`, `needs-profiler-runtime`, `needs-sanitizer-support`, `needs-run-enabled`, `needs-unwind`, `needs-rust-lld`, `needs-threads`, `needs-subprocess`, `needs-symlink`, and others related to debug assertions and atomic support.