Check for profiler support via a flag, instead of an environment var

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

@@ -1976,7 +1976,7 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
         }
 
         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/needs.rs

@@ -238,7 +238,7 @@ impl CachedNeedsConditions {
             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

@@ -62,6 +62,7 @@ struct ConfigBuilder {
     llvm_version: Option<String>,
     git_hash: bool,
     system_llvm: bool,
+    profiler_support: bool,
 }
 
 impl ConfigBuilder {
@@ -100,6 +101,11 @@ impl ConfigBuilder {
         self
     }
 
+    fn profiler_support(&mut self, s: bool) -> &mut Self {
+        self.profiler_support = s;
+        self
+    }
+
     fn build(&mut self) -> Config {
         let args = &[
             "compiletest",
@@ -142,6 +148,9 @@ impl ConfigBuilder {
         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 +349,15 @@ 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 = [

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 @@ pub fn parse_config(args: Vec<String>) -> Config {
 
         git_repository: matches.opt_str("git-repository").unwrap(),
         nightly_branch: matches.opt_str("nightly-branch").unwrap(),
+
+        profiler_support: matches.opt_present("profiler-support"),
     }
 }