Add new `ignore-backends` tests annotations

5 files changed, 80 insertions, 2 deletions

diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index 98f11116279..44bcdeacc1e 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -1757,6 +1757,10 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
         cmd.arg("--host").arg(&*compiler.host.triple);
         cmd.arg("--llvm-filecheck").arg(builder.llvm_filecheck(builder.config.host_target));
 
+        if let Some(codegen_backend) = builder.config.default_codegen_backend(compiler.host) {
+            cmd.arg("--codegen-backend").arg(&codegen_backend);
+        }
+
         if builder.build.config.llvm_enzyme {
             cmd.arg("--has-enzyme");
         }
diff --git a/src/doc/rustc-dev-guide/src/tests/directives.md b/src/doc/rustc-dev-guide/src/tests/directives.md
index 6685add461e..15655d1bb2c 100644
--- a/src/doc/rustc-dev-guide/src/tests/directives.md
+++ b/src/doc/rustc-dev-guide/src/tests/directives.md
@@ -205,6 +205,7 @@ settings:
   on `wasm32-unknown-unknown` target because the target does not support the
   `proc-macro` crate type.
 - `needs-target-std` — ignores if target platform does not have std support.
+- `ignore-backends` — ignores the listed backends, separated by whitespace characters.
 
 The following directives will check LLVM support:
 
diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index c83070aaba7..12084fa0b15 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -175,6 +175,36 @@ pub enum Sanitizer {
     Hwaddress,
 }
 
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum CodegenBackend {
+    Cranelift,
+    Gcc,
+    Llvm,
+}
+
+impl<'a> TryFrom<&'a str> for CodegenBackend {
+    type Error = &'static str;
+
+    fn try_from(value: &'a str) -> Result<Self, Self::Error> {
+        match value.to_lowercase().as_str() {
+            "cranelift" => Ok(Self::Cranelift),
+            "gcc" => Ok(Self::Gcc),
+            "llvm" => Ok(Self::Llvm),
+            _ => Err("unknown backend"),
+        }
+    }
+}
+
+impl CodegenBackend {
+    pub fn as_str(self) -> &'static str {
+        match self {
+            Self::Cranelift => "cranelift",
+            Self::Gcc => "gcc",
+            Self::Llvm => "llvm",
+        }
+    }
+}
+
 /// Configuration for `compiletest` *per invocation*.
 ///
 /// In terms of `bootstrap`, this means that `./x test tests/ui tests/run-make` actually correspond
@@ -651,6 +681,9 @@ pub struct Config {
     /// need `core` stubs in cross-compilation scenarios that do not otherwise want/need to
     /// `-Zbuild-std`. Used in e.g. ABI tests.
     pub minicore_path: Utf8PathBuf,
+
+    /// Current codegen backend used.
+    pub codegen_backend: CodegenBackend,
 }
 
 impl Config {
@@ -753,6 +786,7 @@ impl Config {
             profiler_runtime: Default::default(),
             diff_command: Default::default(),
             minicore_path: Default::default(),
+            codegen_backend: CodegenBackend::Llvm,
         }
     }
 
diff --git a/src/tools/compiletest/src/directives.rs b/src/tools/compiletest/src/directives.rs
index 513716357f4..b773956c69f 100644
--- a/src/tools/compiletest/src/directives.rs
+++ b/src/tools/compiletest/src/directives.rs
@@ -9,7 +9,7 @@ use camino::{Utf8Path, Utf8PathBuf};
 use semver::Version;
 use tracing::*;
 
-use crate::common::{Config, Debugger, FailMode, PassMode, RunFailMode, TestMode};
+use crate::common::{CodegenBackend, Config, Debugger, FailMode, PassMode, RunFailMode, TestMode};
 use crate::debuggers::{extract_cdb_version, extract_gdb_version};
 use crate::directives::auxiliary::{AuxProps, parse_and_update_aux};
 use crate::directives::needs::CachedNeedsConditions;
@@ -818,6 +818,7 @@ const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "ignore-arm-unknown-linux-musleabihf",
     "ignore-auxiliary",
     "ignore-avr",
+    "ignore-backends",
     "ignore-beta",
     "ignore-cdb",
     "ignore-compare-mode-next-solver",
@@ -1669,6 +1670,7 @@ pub(crate) fn make_test_description<R: Read>(
             decision!(cfg::handle_only(config, ln));
             decision!(needs::handle_needs(&cache.needs, config, ln));
             decision!(ignore_llvm(config, path, ln));
+            decision!(ignore_backends(config, path, ln));
             decision!(ignore_cdb(config, ln));
             decision!(ignore_gdb(config, ln));
             decision!(ignore_lldb(config, ln));
@@ -1795,6 +1797,26 @@ fn ignore_lldb(config: &Config, line: &str) -> IgnoreDecision {
     IgnoreDecision::Continue
 }
 
+fn ignore_backends(config: &Config, path: &Utf8Path, line: &str) -> IgnoreDecision {
+    if let Some(backends_to_ignore) = config.parse_name_value_directive(line, "ignore-backends") {
+        for backend in backends_to_ignore.split_whitespace().map(|backend| {
+            match CodegenBackend::try_from(backend) {
+                Ok(backend) => backend,
+                Err(error) => {
+                    panic!("Invalid ignore-backends value `{backend}` in `{path}`: {error}")
+                }
+            }
+        }) {
+            if config.codegen_backend == backend {
+                return IgnoreDecision::Ignore {
+                    reason: format!("{} backend is marked as ignore", backend.as_str()),
+                };
+            }
+        }
+    }
+    IgnoreDecision::Continue
+}
+
 fn ignore_llvm(config: &Config, path: &Utf8Path, line: &str) -> IgnoreDecision {
     if let Some(needed_components) =
         config.parse_name_value_directive(line, "needs-llvm-components")
diff --git a/src/tools/compiletest/src/lib.rs b/src/tools/compiletest/src/lib.rs
index f3b3605a120..41bed8ed8a0 100644
--- a/src/tools/compiletest/src/lib.rs
+++ b/src/tools/compiletest/src/lib.rs
@@ -39,7 +39,7 @@ use walkdir::WalkDir;
 
 use self::directives::{EarlyProps, make_test_description};
 use crate::common::{
-    CompareMode, Config, Debugger, PassMode, TestMode, TestPaths, UI_EXTENSIONS,
+    CodegenBackend, CompareMode, Config, Debugger, PassMode, TestMode, TestPaths, UI_EXTENSIONS,
     expected_output_path, output_base_dir, output_relative_path,
 };
 use crate::directives::DirectivesCache;
@@ -203,6 +203,12 @@ pub fn parse_config(args: Vec<String>) -> Config {
             "debugger",
             "only test a specific debugger in debuginfo tests",
             "gdb | lldb | cdb",
+        )
+        .optopt(
+            "",
+            "codegen-backend",
+            "the codegen backend currently used",
+            "CODEGEN BACKEND NAME",
         );
 
     let (argv0, args_) = args.split_first().unwrap();
@@ -264,6 +270,15 @@ pub fn parse_config(args: Vec<String>) -> Config {
             || directives::extract_llvm_version_from_binary(&matches.opt_str("llvm-filecheck")?),
         );
 
+    let codegen_backend = match matches.opt_str("codegen-backend").as_deref() {
+        Some(backend) => match CodegenBackend::try_from(backend) {
+            Ok(backend) => backend,
+            Err(error) => panic!("invalid value `{backend}` for `--codegen-backend`: {error}"),
+        },
+        // By default, it's always llvm.
+        None => CodegenBackend::Llvm,
+    };
+
     let run_ignored = matches.opt_present("ignored");
     let with_rustc_debug_assertions = matches.opt_present("with-rustc-debug-assertions");
     let with_std_debug_assertions = matches.opt_present("with-std-debug-assertions");
@@ -449,6 +464,8 @@ pub fn parse_config(args: Vec<String>) -> Config {
         diff_command: matches.opt_str("compiletest-diff-tool"),
 
         minicore_path: opt_path(matches, "minicore-path"),
+
+        codegen_backend,
     }
 }