Rollup merge of #119034 - Zalathar:ignore-mode, r=davidtwco

Allow coverage tests to ignore test modes, and to enable color in coverage reports

This PR adds two new header directives to compiletest, intended for use by coverage tests (and by #119033 in particular).

The new headers are:

- `// ignore-mode-{mode}` causes a test to not be run in a particular compiletest mode (e.g. `ignore-mode-coverage-run`).
  - This can theoretically be used by any test, but coverage tests are currently the only ones that automatically run in multiple modes, so it's not very useful for other kinds of test.
- `// llvm-cov-flags: --use-color` makes `coverage-run` tests pass the flag `--use-color` when generating coverage reports.
  - For most tests, non-coloured reports are easier to read and more portable across platforms. But for #119033 specifically, we want to test that `llvm-cov` slices up source text correctly, which only happens when colour output is enabled.

src/bootstrap/src/core/build_steps/test.rs

@@ -1976,7 +1976,7 @@ fn run(self, builder: &Builder<'_>) {
         }
 
         if builder.config.profiler_enabled(target) {
-            cmd.env("RUSTC_PROFILER_SUPPORT", "1");
+            cmd.arg("--profiler-support");
         }
 
         cmd.env("RUST_TEST_TMPDIR", builder.tempdir());

src/tools/compiletest/src/common.rs

@@ -387,6 +387,10 @@ pub struct Config {
     // Needed both to construct build_helper::git::GitConfig
     pub git_repository: String,
     pub nightly_branch: String,
+
+    /// True if the profiler runtime is enabled for this target.
+    /// Used by the "needs-profiler-support" header in test files.
+    pub profiler_support: bool,
 }
 
 impl Config {

src/tools/compiletest/src/header.rs

@@ -178,6 +178,9 @@ pub struct TestProps {
     // Whether to tell `rustc` to remap the "src base" directory to a fake
     // directory.
     pub remap_src_base: bool,
+    /// Extra flags to pass to `llvm-cov` when producing coverage reports.
+    /// Only used by the "coverage-run" test mode.
+    pub llvm_cov_flags: Vec<String>,
 }
 
 mod directives {
@@ -216,6 +219,7 @@ mod directives {
     pub const MIR_UNIT_TEST: &'static str = "unit-test";
     pub const REMAP_SRC_BASE: &'static str = "remap-src-base";
     pub const COMPARE_OUTPUT_LINES_BY_SUBSET: &'static str = "compare-output-lines-by-subset";
+    pub const LLVM_COV_FLAGS: &'static str = "llvm-cov-flags";
     // This isn't a real directive, just one that is probably mistyped often
     pub const INCORRECT_COMPILER_FLAGS: &'static str = "compiler-flags";
 }
@@ -265,6 +269,7 @@ pub fn new() -> Self {
             stderr_per_bitwidth: false,
             mir_unit_test: None,
             remap_src_base: false,
+            llvm_cov_flags: vec![],
         }
     }
 
@@ -321,16 +326,23 @@ fn load_from(&mut self, testfile: &Path, cfg: Option<&str>, config: &Config) {
                     |r| r,
                 );
 
-                if let Some(flags) = config.parse_name_value_directive(ln, COMPILE_FLAGS) {
-                    self.compile_flags.extend(
-                        flags
-                            .split("'")
-                            .enumerate()
-                            .flat_map(|(i, f)| {
+                fn split_flags(flags: &str) -> Vec<String> {
+                    // Individual flags can be single-quoted to preserve spaces; see
+                    // <https://github.com/rust-lang/rust/pull/115948/commits/957c5db6>.
+                    flags
+                        .split("'")
+                        .enumerate()
+                        .flat_map(
+                            |(i, f)| {
                                 if i % 2 == 1 { vec![f] } else { f.split_whitespace().collect() }
-                            })
-                            .map(|s| s.to_owned()),
-                    );
+                            },
+                        )
+                        .map(move |s| s.to_owned())
+                        .collect::<Vec<_>>()
+                }
+
+                if let Some(flags) = config.parse_name_value_directive(ln, COMPILE_FLAGS) {
+                    self.compile_flags.extend(split_flags(&flags));
                 }
                 if config.parse_name_value_directive(ln, INCORRECT_COMPILER_FLAGS).is_some() {
                     panic!("`compiler-flags` directive should be spelled `compile-flags`");
@@ -488,6 +500,10 @@ fn load_from(&mut self, testfile: &Path, cfg: Option<&str>, config: &Config) {
                     COMPARE_OUTPUT_LINES_BY_SUBSET,
                     &mut self.compare_output_lines_by_subset,
                 );
+
+                if let Some(flags) = config.parse_name_value_directive(ln, LLVM_COV_FLAGS) {
+                    self.llvm_cov_flags.extend(split_flags(&flags));
+                }
             });
         }
 

src/tools/compiletest/src/header/cfg.rs

@@ -1,4 +1,4 @@
-use crate::common::{CompareMode, Config, Debugger};
+use crate::common::{CompareMode, Config, Debugger, Mode};
 use crate::header::IgnoreDecision;
 use std::collections::HashSet;
 
@@ -208,6 +208,17 @@ macro_rules! condition {
         },
         message: "when comparing with {name}",
     }
+    // Coverage tests run the same test file in multiple modes.
+    // If a particular test should not be run in one of the modes, ignore it
+    // with "ignore-mode-coverage-map" or "ignore-mode-coverage-run".
+    condition! {
+        name: format!("mode-{}", config.mode.to_str()),
+        allowed_names: ContainsPrefixed {
+            prefix: "mode-",
+            inner: Mode::STR_VARIANTS,
+        },
+        message: "when the test mode is {name}",
+    }
 
     if prefix == "ignore" && outcome == MatchOutcome::Invalid {
         // Don't error out for ignore-tidy-* diretives, as those are not handled by compiletest.

src/tools/compiletest/src/header/needs.rs

@@ -238,7 +238,7 @@ pub(super) fn load(config: &Config) -> Self {
             sanitizer_memtag: sanitizers.contains(&Sanitizer::Memtag),
             sanitizer_shadow_call_stack: sanitizers.contains(&Sanitizer::ShadowCallStack),
             sanitizer_safestack: sanitizers.contains(&Sanitizer::Safestack),
-            profiler_support: std::env::var_os("RUSTC_PROFILER_SUPPORT").is_some(),
+            profiler_support: config.profiler_support,
             xray: config.target_cfg().xray,
 
             // For tests using the `needs-rust-lld` directive (e.g. for `-Clink-self-contained=+linker`),

src/tools/compiletest/src/header/tests.rs

@@ -1,7 +1,8 @@
 use std::io::Read;
 use std::path::Path;
+use std::str::FromStr;
 
-use crate::common::{Config, Debugger};
+use crate::common::{Config, Debugger, Mode};
 use crate::header::{parse_normalization_string, EarlyProps, HeadersCache};
 
 fn make_test_description<R: Read>(
@@ -55,6 +56,7 @@ fn test_parse_normalization_string() {
 
 #[derive(Default)]
 struct ConfigBuilder {
+    mode: Option<String>,
     channel: Option<String>,
     host: Option<String>,
     target: Option<String>,
@@ -62,9 +64,15 @@ struct ConfigBuilder {
     llvm_version: Option<String>,
     git_hash: bool,
     system_llvm: bool,
+    profiler_support: bool,
 }
 
 impl ConfigBuilder {
+    fn mode(&mut self, s: &str) -> &mut Self {
+        self.mode = Some(s.to_owned());
+        self
+    }
+
     fn channel(&mut self, s: &str) -> &mut Self {
         self.channel = Some(s.to_owned());
         self
@@ -100,10 +108,16 @@ fn system_llvm(&mut self, s: bool) -> &mut Self {
         self
     }
 
+    fn profiler_support(&mut self, s: bool) -> &mut Self {
+        self.profiler_support = s;
+        self
+    }
+
     fn build(&mut self) -> Config {
         let args = &[
             "compiletest",
-            "--mode=ui",
+            "--mode",
+            self.mode.as_deref().unwrap_or("ui"),
             "--suite=ui",
             "--compile-lib-path=",
             "--run-lib-path=",
@@ -142,6 +156,9 @@ fn build(&mut self) -> Config {
         if self.system_llvm {
             args.push("--system-llvm".to_owned());
         }
+        if self.profiler_support {
+            args.push("--profiler-support".to_owned());
+        }
 
         args.push("--rustc-path".to_string());
         // This is a subtle/fragile thing. On rust-lang CI, there is no global
@@ -340,6 +357,15 @@ fn sanitizers() {
     assert!(check_ignore(&config, "// needs-sanitizer-thread"));
 }
 
+#[test]
+fn profiler_support() {
+    let config: Config = cfg().profiler_support(false).build();
+    assert!(check_ignore(&config, "// needs-profiler-support"));
+
+    let config: Config = cfg().profiler_support(true).build();
+    assert!(!check_ignore(&config, "// needs-profiler-support"));
+}
+
 #[test]
 fn asm_support() {
     let asms = [
@@ -530,3 +556,17 @@ fn families() {
         assert!(!check_ignore(&config, &format!("// ignore-{other}")));
     }
 }
+
+#[test]
+fn ignore_mode() {
+    for &mode in Mode::STR_VARIANTS {
+        // Indicate profiler support so that "coverage-run" tests aren't skipped.
+        let config: Config = cfg().mode(mode).profiler_support(true).build();
+        let other = if mode == "coverage-run" { "coverage-map" } else { "coverage-run" };
+        assert_ne!(mode, other);
+        assert_eq!(config.mode, Mode::from_str(mode).unwrap());
+        assert_ne!(config.mode, Mode::from_str(other).unwrap());
+        assert!(check_ignore(&config, &format!("// ignore-mode-{mode}")));
+        assert!(!check_ignore(&config, &format!("// ignore-mode-{other}")));
+    }
+}

src/tools/compiletest/src/lib.rs

@@ -142,6 +142,7 @@ pub fn parse_config(args: Vec<String>) -> Config {
         .optflag("", "force-rerun", "rerun tests even if the inputs are unchanged")
         .optflag("", "only-modified", "only run tests that result been modified")
         .optflag("", "nocapture", "")
+        .optflag("", "profiler-support", "is the profiler runtime enabled for this target")
         .optflag("h", "help", "show this message")
         .reqopt("", "channel", "current Rust channel", "CHANNEL")
         .optflag("", "git-hash", "run tests which rely on commit version being compiled into the binaries")
@@ -315,6 +316,8 @@ fn make_absolute(path: PathBuf) -> PathBuf {
 
         git_repository: matches.opt_str("git-repository").unwrap(),
         nightly_branch: matches.opt_str("nightly-branch").unwrap(),
+
+        profiler_support: matches.opt_present("profiler-support"),
     }
 }
 

src/tools/compiletest/src/runtest.rs

@@ -575,6 +575,8 @@ fn run_coverage_run_test(&self) {
                 cmd.arg("--object");
                 cmd.arg(bin);
             }
+
+            cmd.args(&self.props.llvm_cov_flags);
         });
         if !proc_res.status.success() {
             self.fatal_proc_rec("llvm-cov show failed!", &proc_res);

tests/coverage/color.coverage

@@ -0,0 +1,13 @@
+   LL|       |// edition: 2021
+   LL|       |// ignore-mode-coverage-map
+   LL|       |// ignore-windows
+   LL|       |// llvm-cov-flags: --use-color
+   LL|       |
+   LL|       |// Verify that telling `llvm-cov` to use colored output actually works.
+   LL|       |// Ignored on Windows because we can't tell the tool to use ANSI escapes.
+   LL|       |
+   LL|      1|fn main() {
+   LL|      1|    for _i in 0..0 {}
+                      ^0         ^0
+   LL|      1|}
+

tests/coverage/color.rs

@@ -0,0 +1,11 @@
+// edition: 2021
+// ignore-mode-coverage-map
+// ignore-windows
+// llvm-cov-flags: --use-color
+
+// Verify that telling `llvm-cov` to use colored output actually works.
+// Ignored on Windows because we can't tell the tool to use ANSI escapes.
+
+fn main() {
+    for _i in 0..0 {}
+}

tests/coverage/ignore_map.coverage

@@ -0,0 +1,4 @@
+   LL|       |// ignore-mode-coverage-map
+   LL|       |
+   LL|      1|fn main() {}
+

tests/coverage/ignore_map.rs

@@ -0,0 +1,3 @@
+// ignore-mode-coverage-map
+
+fn main() {}

tests/coverage/ignore_run.cov-map

@@ -0,0 +1,8 @@
+Function name: ignore_run::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 03, 01, 00, 0d]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 3, 1) to (start + 0, 13)
+

tests/coverage/ignore_run.rs

@@ -0,0 +1,3 @@
+// ignore-mode-coverage-run
+
+fn main() {}