Support breakpoint intrinsic

Author: syvb

src/shims/intrinsics.rs

@@ -654,6 +654,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
             "try" => return this.handle_try(args, dest, ret),
 
+            "breakpoint" => {
+                // normally this would raise a SIGTRAP, which aborts if no debugger is connected
+                throw_machine_stop!(TerminationInfo::Abort("Trace/breakpoint trap".to_string()))
+            }
+
             name => throw_unsup_format!("unimplemented intrinsic: {}", name),
         }
 

tests/compile-fail/breakpoint.rs

@@ -0,0 +1,7 @@
+#![feature(core_intrinsics)]
+
+fn main() {
+    unsafe {
+        core::intrinsics::breakpoint() //~ ERROR Trace/breakpoint trap
+    };
+}