cli: Add frust-extern optiondevel/rust/master

Add a new option to gather extern crates location.

gcc/rust/ChangeLog:

	* lang.opt: Add frust-extern option.
	* rust-session-manager.cc (Session::handle_extern_option): Add
	frust-extern option handler.
	* rust-session-manager.h (struct Session): Add an unordered map
	to store library name and locations.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/gcc/rust/rust-session-manager.cc b/gcc/rust/rust-session-manager.cc
index e537b413d16..5d1326e5aca 100644
--- a/gcc/rust/rust-session-manager.cc
+++ b/gcc/rust/rust-session-manager.cc
@@ -190,6 +190,11 @@ Session::handle_option (
       }
       break;
 
+      case OPT_frust_extern_: {
+	std::string input (arg);
+	ret = handle_extern_option (input);
+      }
+      break;
     case OPT_frust_crate_:
       // set the crate name
       if (arg != nullptr)
@@ -250,6 +255,20 @@ Session::handle_option (
 }
 
 bool
+Session::handle_extern_option (std::string &input)
+{
+  auto pos = input.find ('=');
+  if (std::string::npos == pos)
+    return false;
+
+  std::string libname = input.substr (0, pos);
+  std::string path = input.substr (pos + 1);
+
+  extern_crates.insert ({libname, path});
+  return true;
+}
+
+bool
 Session::handle_cfg_option (std::string &input)
 {
   std::string key;