Provide option for specifying the profiler runtime

Currently, if `-Zinstrument-coverage` is enabled, the target is linked
against the `library/profiler_builtins` crate (which pulls in LLVM's
compiler-rt runtime).

This option enables backends to specify an alternative runtime crate for
handling injected instrumentation calls.

1 files changed, 21 insertions, 17 deletions

diff --git a/compiler/rustc_metadata/src/creader.rs b/compiler/rustc_metadata/src/creader.rs
index e9ae22f8ced..8108470e3d3 100644
--- a/compiler/rustc_metadata/src/creader.rs
+++ b/compiler/rustc_metadata/src/creader.rs
@@ -769,27 +769,31 @@ impl<'a> CrateLoader<'a> {
     }
 
     fn inject_profiler_runtime(&mut self, krate: &ast::Crate) {
-        if (self.sess.instrument_coverage()
+        if self.sess.instrument_coverage()
             || self.sess.opts.debugging_opts.profile
-            || self.sess.opts.cg.profile_generate.enabled())
-            && !self.sess.opts.debugging_opts.no_profiler_runtime
+            || self.sess.opts.cg.profile_generate.enabled()
         {
-            info!("loading profiler");
-
-            if self.sess.contains_name(&krate.attrs, sym::no_core) {
-                self.sess.err(
-                    "`profiler_builtins` crate (required by compiler options) \
-                               is not compatible with crate attribute `#![no_core]`",
-                );
-            }
+            if let Some(name) =
+                self.sess.opts.debugging_opts.profiler_runtime.as_deref().map(Symbol::intern)
+            {
+                info!("loading profiler");
+
+                if name == sym::profiler_builtins
+                    && self.sess.contains_name(&krate.attrs, sym::no_core)
+                {
+                    self.sess.err(
+                        "`profiler_builtins` crate (required by compiler options) \
+                                is not compatible with crate attribute `#![no_core]`",
+                    );
+                }
 
-            let name = sym::profiler_builtins;
-            let cnum = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit, None);
-            let data = self.cstore.get_crate_data(cnum);
+                let cnum = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit, None);
+                let data = self.cstore.get_crate_data(cnum);
 
-            // Sanity check the loaded crate to ensure it is indeed a profiler runtime
-            if !data.is_profiler_runtime() {
-                self.sess.err("the crate `profiler_builtins` is not a profiler runtime");
+                // Sanity check the loaded crate to ensure it is indeed a profiler runtime
+                if !data.is_profiler_runtime() {
+                    self.sess.err(&format!("the crate `{}` is not a profiler runtime", name));
+                }
             }
         }
     }