Expose pretty print routines that accept just mir (no need for a NodeId).

src/librustc_mir/pretty.rs

@@ -269,6 +269,29 @@ fn write_scope_tree(tcx: TyCtxt,
     Ok(())
 }
 
+pub fn write_mir_named(tcx: &ty::TyCtxt, name: &str, mir: &Mir, w: &mut Write, auxiliary: Option<&ScopeAuxiliaryVec>)
+-> io::Result<()> {
+
+    let annotations = scope_entry_exit_annotations(auxiliary);
+    write_mir_intro_named(tcx, name, mir, w)?;
+    for block in mir.all_basic_blocks() {
+        write_basic_block(tcx, block, mir, w, &annotations)?;
+    }
+    writeln!(w, "}}")
+}
+
+/// Write out a human-readable textual representation of the MIR's
+/// `fn` type and the types of its local variables (both user-defined
+/// bindings and compiler temporaries). Assumes the function
+/// represented by `mir` is named `name`. Note: Generated output
+/// introduces an open curly that needs to be closed.
+pub fn write_mir_intro_named(tcx: &ty::TyCtxt, name: &str, mir: &Mir, w: &mut Write)
+-> io::Result<()> {
+    write_mir_fn_sig(tcx, name, mir, w)?;
+    writeln!(w, " {{")?;
+    write_mir_fn_decls(tcx, mir, w)
+}
+
 /// Write out a human-readable textual representation of the MIR's `fn` type and the types of its
 /// local variables (both user-defined bindings and compiler temporaries).
 fn write_mir_intro<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,